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INTRAOPERATIVE HEMODYNAMIC PERFORMANCE AND
TRANSESOPHAGEAL ECHOCARDIOGRAPHIC (TEE)
CHARACTERISTICS EVALUATION OF CHITRA HEART VALVE
PROSTHESIS (CHVP) IMPLANTED AT AORTIC POSITION
THESIS PROJECT
BY
DR. M. S. SARAVANA BABU
DM CARDIOTHORACIC AND VASCULAR ANAESTHESIA
2014 – 2016
DEPARTMENT OF ANAESTHESIOLOGY
SREE CHITRA TIRUNAL INSTITUTE FOR MEDICAL
SCIENCES AND TECHNOLOGY, TRIVANDRUM,
KERALA,
INDIA – 695011
ii
DECLARATION
I hereby declare that this thesis entitled, “INTRAOPERATIVE HEMODYNAMIC
PERFORMANCE AND TRANSESOPHAGEAL ECHOCARDIOGRAPHIC (TEE)
CHARACTERISTICS EVALUATION OF CHITRA HEART VALVE PROSTHESIS
(CHVP) IMPLANTED AT AORTIC POSITION” has been prepared by me under the capable
supervision and guidance of
Dr. Rupa Sreedhar,
Professor and Head,
Division of Cardiothoracic and Vascular Anesthesiology,
Department of Anesthesiology,
Sree Chitra Tirunal Institute for Medical Sciences & Technology, Thiruvananthapuram, Kerala.
Place: Thiruvananthapuram
Date: 29.09.2016
Dr. M. S. Saravana Babu
DM Cardiothoracic and Vascular
Anesthesiology Resident,
Department of Anesthesiology,
SCTIMST, Thiruvananthapuram.
iii
CERTIFICATE
This is to certify that this thesis entitled, “INTRAOPERATIVE
HEMODYNAMIC PERFORMANCE AND TRANSESOPHAGEAL
ECHOCARDIOGRAPHIC (TEE) CHARACTERISTICS EVALUATION OF CHITRA
HEART VALVE PROSTHESIS (CHVP) IMPLANTED AT AORTIC POSITION” has
been prepared by Dr. M. S. SARAVANA BABU, DM Cardiothoracic and Vascular
Anesthesiology Resident, Division of Cardiothoracic and Vascular Anesthesiology, at Sree
Chitra Tirunal Institute for Medical Sciences & Technology, Thiruvananthapuram. He has shown
keen interest in preparing this project.
(GUIDE)
Dr. Rupa Sreedhar, MD, DNBE, PDCC
Professor of Anesthesiology, SCTIMST, Thiruvananthapuram
(COGUIDE)
Dr. Shrinivas V. Gadhinglajkar, MD, PDCC
Professor of Anesthesiology, SCTIMST, Thiruvananthapuram
(COGUIDE)
Dr. Prasanta Kumar Dash, MD, PDCC
Professor of Anesthesiology, SCTIMST, Thiruvananthapuram
iv
(COGUIDE)
Dr. Vivek V. Pillai, MS, MCh, Additional Professor of CVTS,
SCTIMST, Thiruvananthapuram.
(COGUIDE)
Dr. Vargheese T. Panicker, MS, MCh, Additional Professor of CVTS,
SCTIMST, Thiruvananthapuram.
v
CERTIFICATE
This is to certify that this thesis entitled, “INTRAOPERATIVE HEMODYNAMIC
PERFORMANCE AND TRANSESOPHAGEAL ECHOCARDIOGRAPHIC (TEE)
CHARACTERISTICS EVALUATION OF CHITRA HEART VALVE PROSTHESIS
(CHVP) IMPLANTED AT AORTIC POSITION” has been prepared by
Dr. M. S. SARAVANA BABU, DM Cardiothoracic and Vascular Anesthesiology Resident,
Division of Cardiothoracic and Vascular Anesthesiology, at Sree Chitra Tirunal Institute for
Medical Sciences & Technology, Thiruvananthapuram. He has shown keen interest in preparing
this project.
Place: Thiruvananthapuram Dr. Rupa Sreedhar,
Date: 29.09.2016 Professor and Head,
Division of Cardiothoracic and Vascular Anesthesiology,
Department of Anesthesiology, SCTIMST,
Thiruvananthapuram.
vi
ACKNOWLEDGEMENT
I would like to express my gratitude to all those who have contributed towards the
completion of this thesis.
First and foremost, I offer my sincere acknowledgement and gratitude to
Professor, Dr. Rupa Sreedhar, my chief guide and Head of the Division of Cardiothoracic
and Vascular Anesthesia, who created a congenial atmosphere at the workplace to enable
me to complete this thesis by providing me all the requisite infrastructure of the Institute.
Needless to say, she continues to be a source of strength for all the residents in the
Department, each and every one of whom cherishes her motherly care.
I would like to express my deep sense of gratitude to Dr. Shrinivas V.
Gadhinglajkar, my co-guide in this endeavor; he was instrumental in framing the idea of
the project, he inspired and supported me during the study, and tirelessly guided me
throughout the course of this herculean effort. A clinician par excellence, he never fails to
inspire anybody who is privileged to be associated with him. He has been a true pillar of
support during my DM course and has been my mentor over the past three years. I am
truly honored to have him as my co-guide.
I would also like to acknowledge the guidance and support of my co-guides in this
project Dr. Prasanta Kumar Dash, Dr. Vivek V. Pillai and Dr. Vargheese T. Panicker.
I am also deeply indebted to my teachers, Dr. Thomas Koshy, Dr. Unni Krishnan
and Dr. Suneel who constantly supported and encouraged me during the past 3 years. I
am grateful to Dr. Subin Sukesan for his constant help, support and encouragement
throughout the duration of my course.
vii
I am thankful to my fellow residents Dr. Neelam Aggarwal, Dr. Deepak Mathew
Gregory, Dr. Keerthi Chigurupati, Dr. Lovhale Pravin Shriram and Dr. Rajesh for their
constant help and support throughout the study. My senior colleagues Dr. Uvaraj and Dr.
Jagadeesh deserves special mention for their support and guidance.
I would be failing in my duty if I do not acknowledge my deep gratitude to my
junior colleagues, Dr. Muthu Kumar, Dr. Balaji, Dr. Indranil Biswas, Dr. Kirubanand,
Dr. Kappian and Dr. Manjusha Pillai for their invaluable efforts in bringing out this
study.
My gratitude and sincere thanks to all the patients who willingly agreed to be a
part of the study.
I express my heartiest gratitude and sincere regards to my parents and family for
their support and encouragement throughout my educational career.
Last, but not the least, I would like to thank the Almighty God for giving me the wisdom
and health to make this thesis a reality.
Place: Thiruvananthapuram Dr. M.S. Saravana Babu Date: 29.09.2016
viii
DEDICATION
My humble effort I dedicate to my loving mother & father,
Dear mom and dad,
Many things have changed in my life over time, but your constant love, support
and encouragement has never failed me. Thank you for backing my every decision,
Thanks for being there always………….
Along with all hard working and respected
TEACHERS.
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CONTENTS
Sl. No Topic Page No
1 Introduction 1
2 Review of Literature 7
3 Aims and Objectives 29
4 Materials and Methods 32
5 Results and Observations 39
6 Discussion 58
7 Limitation of the study 69
8 Conclusion 71
9 Bibliography 74
Annexures
A List of abbreviations 86
B Consent form 88
C Observation chart 95
D TAC approval 99
E IEC approval 100
F Plagiarism originality report 102
G Master Chart 103
1
INTRODUCTION
2
INTRODUCTION
The history of Chitra heart valve prosthesis (CHVP) started with an ardent clinical
and social necessity in India, where the incidence of rheumatic fever and rheumatic heart disease
were high among the young population. In early 1970’s, nearly 2-2.5 million patients were
suffering from rheumatic heart disease in India. This was the foremost reason for the structural
damage of the heart valves resulting in heart failure and death. For many years, India relied on
imports of costly artificial valves to meet the national need. But many poor families in India
could not afford even the profoundly discounted price of imported artificial valves. To address
this domestic health challenge, search for an affordable, high quality, indigenous artificial heart
valve to meet international standards was commenced in 1976 by Dr. M.S. Valiathan through a
project funded by the Ministry of Science and Technology.
The mechanical heart valve must resist the stress of opening and closing some
forty million times a year. The raw materials used for manufacturing the valve should be bio-
compatible. In open position, blood should flow through the valve smoothly without any
turbulence or shear and tear to the valve leaflets. When closed, the regurgitation of blood should
be minimal. Design related features and drawbacks of mechanical heart valves which are most
commonly implanted in patients with valvular heart disease1 are portrayed in Table 1.
3
Table1:- Characteristics and drawbacks of different valve types1
VALVE TYPE
CHARACTERISTICS
DRAWBACKS
Caged ball valve
Time tested
Structurally complete built-in
redundancy in the strut design
Low levels of regurgitation in
the closed stage.
Comparatively large valve
height
Flow separation at
downstream of the valve,
may lead to thrombus
formation
Tilting
disc valve
Better hemodynamic features
than the caged ball valve
design
Lower height and hence
appropriate for all anatomical
sites
Large number of tilting disc
valves have been implanted till
date
The redundancy in the
cage strut structure is low
Low flow across the
minor orifice can lead to
tissue over growth and
thrombosis
Strut fracture and other
related complications
Bileaflet valve
Flow profiles across the
orifices are uniform
Low structural problems
Hinge design is
susceptible to
thrombus formation and
valve dysfunction
Escapement of leaflets
was reported in some
models
TTK Chitra heart valve prosthesis (CHVP) is a homegrown tilting disc artificial
heart valve designed and developed by Sree Chitra Tirunal Institute for Medical Sciences and
Technology (SCTIMST), India which was subjected to repetitive testing for improvising the
design. It has almost more than 90,000 implantations to date across the globe. On the whole
about 250 health centers and more than 300 surgeons were using the CHVP as of 2015 statistics.
Many patients with valvular heart diseases have been benefited after implantation of CHVP.
4
Chitra heart valve prosthesis has three main components (Figure 1)
1. Frame
2. Disc
3. Sewing ring
Figure 1:- Chitra heart valve prosthesis (CHVP)
Chitra heart valve prosthesis is routinely implanted in many hospitals all over the
globe. It is a single leaflet tilting-disc valve with an annular metallic stent, which is stitched to
the innate valve annulus with a sewing ring. The circular disc acts as an occluder, which is
suspended from the annular metallic ring by a single strut. The disc gets attached to the strut
eccentrically in such a way that the back pressure on the larger portion of the disc will tend to
close the valve. The disc occluder hinges open at 60 to 75 degrees. The eccentric location of the
5
disc produces two openings of different size and shape; a major orifice and a minor orifice
(Figure 1). The valve has an intricate flow pattern, wherein 70% of flow goes through the major
orifice and the remaining 30% passes through the minor orifice. This complex flow generates
resistance to forward flow and a larger zone of stagnation on the downstream surface of the disc.
Transesophageal echocardiography (TEE) is a valuable monitoring device during
cardiac surgery2. Studies have reported that TEE assessment of the prosthetic valve after
weaning the patient from cardiopulmonary bypass (CPB) has guided surgeons on many
occasions to alter the course of surgery3. Since TEE is now being used as a routine during valve
surgeries, cardiac surgeons depend on the post-CPB TEE observations to take surgical decisions
on the operation table. So it has become necessary for a perioperative physician to get well
acquainted with the normal echo-characteristics of the CHVP. However, till date there are no
intraoperative studies depicting the echocardiographic characteristics and hemodynamic flow
profile of the CHVP at aortic position.
Major complications associated with prosthetic valve implantation are prosthetic
valve regurgitation, stenosis and patient- prosthesis mismatch (PPM) 4
. This should be detected
and addressed as early as possible for preventing hemodynamic worsening5. Post-CPB period is
the most suitable time to deal with these complications.
However, the Doppler features of prosthetic valve observed in the post-CPB
period may not be similar to those noted in the postoperative follow up. This is because the
Doppler assessment is influenced by multiple factors in the intraoperative period including use of
inotropes, changing preload conditions, CPB-induced myocardial edema and inadequate
myocardial preservation.
6
Even though numerous studies have proven the long-term safety and efficacy of
CHVP implanted at aortic position6-8
, none of them had defined its normal intra-operative TEE
characteristics in the immediate post-CPB period, which are necessary in making important
intraoperative surgical decisions. Therefore, we conducted this study to evaluate the
intraoperative TEE characteristics of CHVP implanted at aortic position and also to assess the
utility of TEE in prediction of PPM in the perioperative period.
7
REVIEW OF LITERATURE
8
REVIEW OF LITERATURE
Degenerative and rheumatic disease remain the most common etiological factors
for the significant aortic valvular lesions. The treatment modalities include valve repair or
replacement. Although repair techniques for mitral and tricuspid valvular lesions are well
established, aortic valve repairs are still in the emerging phase. So valve replacement with a
mechanical valve or a bio-prosthesis is the most common choice for many patients suffering
from aortic valve disease. The diagnosis of prosthetic valve dysfunction may be difficult at times
because their presenting features are non-specific and mimic other cardiac pathologies such as
ventricular failure, pulmonary artery hypertension or other valvular diseases. So various imaging
modalities are always necessary along with clinical examination to confirm the prosthetic valve
dysfunction. In addition, the detection of prosthetic valve dysfunction may be confounded by
their variable intrinsic properties depending upon their design and type. For example, central
trivial regurgitation is a regular feature in stented bio-prosthetic and Medtronic-Hall tilting disc
valves unlike the bileaflet mechanical valves. The pressure drop across the valve orifices varies
among the bileaflet, tilting-disc and bio-prosthetic valve. Among the imaging modalities such as
cine-fluoroscopy, computed tomography and magnetic resonance imaging, the two dimensional
(2D) echocardiographic Doppler evaluation is the method of choice for the non-invasive
evaluation of the prosthetic valve function9.
Two dimensional transthoracic and TTE are the most common echocardiographic
imaging modalities used for the assessment of prosthetic valve function10
. Although transthoracic
echocardiography (TTE) is non-invasive and easy to perform, it has many limitations including
poor image quality due to thoracic tissues shielding the heart, multiple artefacts, need for
9
multiple probe angulations and off axis views. Also TTE cannot be used in the perioperative
period to assess the prosthetic valve function, because the presence of pericardial drains and air
may degrade the image quality. Therefore, TEE being less invasive and being capable of
producing good quality images, has become a mandatory tool in the intraoperative period for the
assessment of mechanical valves in the aortic position.
TEE is indicated in all open-heart procedures performed for valvular heart
diseases2. Perioperative TEE plays a pivotal role in surgical decision making and to evaluate the
success of surgical repair11
. In our study, we define the utility of intraoperative TEE in
evaluating the function of CHVP implanted at aortic position. The intraoperative
echocardiographic characteristics and hemodynamic performance of CHVP was studied and the
values were compared with the echocardiographic parameters of other aortic mechanical heart
valves in common practise. The intraoperative echocardiographic Doppler parameters of CHVP
was also compared with the data obtained by the TTE in the postoperative period.
Doppler evaluation of prosthetic valves
Rosenhek et al 12
analyzed the normal Doppler echocardiographic data for the
aortic and mitral prosthetic valves available in the literature and provided a comprehensive
overview for accurate interpretation of Doppler parameters. In this study, they concluded that the
normal values for peak velocity, mean gradient and effective orifice area (EOA) across the aortic
and mitral valve prosthesis are attributed to their flow rates and require correlation with the valve
type and size. Therefore, the normal Doppler values for the prosthetic valves should be defined
based on the specific flow rate.
10
Published studies on CHVP
Kumar et al 13
did an evaluative study on the Doppler and hemodynamic
characteristics of CHVP implanted at aortic and mitral position during the follow up period. Out
of 547 patients, 238 patients were examined for Doppler evaluation of transvalvular gradients
and estimation of effective orifice area. For CHVP implanted in aortic position, the valve sizes
21 and 23 mm produced the mean gradients (in mm Hg) of 10±5 and 9±4, and EOAs (in cm2) of
1.5±0.5 and 1.8±0.3 respectively. In the mitral position, the valve sizes 25, 27 and 29 mm
produced the mean gradients (in mm Hg) of 5±3, 4±2 and 4±2, and effective orifice areas (in
cm2) of 2.8±0.8, 3.1±0.7 and 2.9±0.7 respectively. Their study gave a conclusion that TTK
CHVP is hemodynamically comparable with other mechanical heart valves and their
complication rates are similar.
Namboodiri et al 14
studied the Doppler parameters of CHVP in aortic position to
establish normal reference values for them. The peak gradient and mean gradients across the
valve ranged from 7.7 to 66 mm Hg, and from 3.6 to 37 mm Hg, respectively. The peak velocity
and the peak and mean gradients showed a negative correlation with the increase in valve size (r
= − 0.71, r = − 0.69, and r = − 0.68 respectively; p value < 0.001). A significant positive
correlation was seen between the EOA and the valve size (r = 0.81, p value < 0.001). DVI
showed a poor correlation with valve size (r = − 0.05, p value 0.73). The Doppler parameters
such as velocity and gradients were flow dependent and Doppler velocity index (DVI) was
relatively flow independent. The authors also found that the Doppler parameters of CHVP
measured in the study were comparable to other prosthetic aortic valves in common practise.
These Doppler parameters should act as reference for the prosthetic valve assessment in clinical
practice.
11
Namboodiri et al 15
, in another study described the Doppler echocardiographic
parameters of mitral CHVP in 40 patients. The study aim was to determine the normal Doppler
parameters of CHVP in mitral position and to assess whether the mitral valve area derived by
continuity equation (CE) and pressure half time were comparable. The valve sizes included in
the study were 25, 27 and 29 mm. They drew a conclusion that mitral CHVP is associated with
normal hemodynamic parameters and Doppler profile which are comparable with those of other
different mechanical valves in common use. Calculated valve areas by CE and pressure half time
methods were similar in all three groups of patients. Mitral valve area calculated by both of these
methods is smaller than that of the actual orifice area provided by the manufacturer of the
CHVP.
Doppler evaluation of prosthetic valves as recommended by ASE
Zoghbi et al5, 16
in their American society of Echocardiography recommended
guidelines describe the echocardiographic assessment of patients with prosthetic valves. The
recommendation states that almost all prosthetic valves are inherently mild stenotic in nature in
comparison with normally functioning native valves. The degree of obstruction is determined by
the size and type of the valve implanted. Therefore it would be necessary to distinguish the mild
inherent stenosis of the prosthesis from that of pathological stenosis and PPM. The pattern of
physiological regurgitation associated with the prosthetic valve also varies with the design of the
valve. TEE is strongly indicated for the evaluation of prosthetic valve function and detection of
any complications such as PPM and pathologic regurgitation. Apart from valve assessment, it
also focuses on the cardiac evaluation such as measurement of size of cardiac chambers, Left
ventricular (LV) wall thickness and mass, and evaluation of LV systolic and diastolic function.
Valves are imaged in multiple views. The principles of Doppler interrogation of the prosthetic
12
valves are similar to those used in evaluating native valve stenosis or regurgitation. In patients
with aortic prosthesis, measurements of the aortic root and ascending aorta are recommended
(Table 2)
Table 2: Essential parameters in the complete assessment of prosthetic valve function
as recommended by ASE5
Information Parameter
Clinical information
Valve replacement date
Size and type of the valve
Weight, height and body surface area
Symptoms and sings
heart rate and Blood pressure
2D Imaging
Leaflets motion or occluder mechanism
Leaflets calcification or abnormal echo densities on the
prosthesis components
Integrity and motion of the sewing ring
Doppler echocardiography
Contour of the velocity jet
Peak velocity and peak gradient
Mean gradient
Velocity time integral of the jet
DVI (LVOT VTI/ AVprosthesis VTI)
Effective orifice area
Presence, location and severity of valvular regurgitation
Other echocardiographic data Biventricular size, function, and hypertrophy
Left and right atrial size
Concomitant valvular lesions
Assessment of pulmonary artery pressure
Size of aortic root and ascending aorta
Previous postoperative
studies
Particularly helpful in suspected prosthetic valvular
dysfunction
13
EXAMINATION OF THE PROSTHETIC AORTIC VALVE IN THE
INTRAOPERATIVE PERIOD5
Echocardiographic imaging considerations
As per the recommendations by the ASE, echocardiographic imaging should
evaluate the valve seating, motion of leaflets, occluder mechanism, angle of opening and the
surrounding area. Sometimes it may be essential to magnify the real time images using zoom
mode to have a clear view. Manipulation of the imaging plane may be needed until the occluder
mechanism of a tilting disc valve is visualized. The tilting disc is indistinctly imaged due to
reverberations artifacts, whereas the leaflets of normal tissue valves show an unrestricted motion.
In case of aortic valve prosthesis, left ventricular outflow tract (LVOT) should be delineated well
for the measurement of LVOT diameter and EOA. A 10% error in the measurement of LVOT
diameter will produce 19% error in the EOA and cardiac output measurement 17
.
Doppler echocardiography of prosthetic aortic valve
A complete Doppler evaluation comprises of color Doppler, pulse wave Doppler
(PWD) and continuous wave (CWD) Doppler examination in multiple imaging views.
Manipulation of TEE probe may be necessary to align the Doppler beam at a minimal angulation
with the flow. Doppler examination of aortic valve prosthesis includes an estimation of peak
velocity, peak and mean pressure gradients, acceleration time (AT), acceleration time/ejection
time ratio (AT/ET), DVI, cardiac output and EOA. The simplified Bernoulli equation is utilized
in calculating the pressure gradients across the valves. The pressure gradients are flow-dependent
and are overestimated in presence of inotropes and high cardiac output states. For prosthetic
aortic valves, EOA is calculated using CE. Many studies have proven that EOA is a valuable
14
parameter for evaluation of prosthetic valves and it correlates well with the size of the
prosthesis18, 19
. However, estimation of EOA is influenced by the site of measurement of LVOT
diameter and the site of placement of sample volume for measuring the LVOT velocity time
integral (VTI). Bileaflet prosthetic heart valves show a pressure recovery phenomenon
characterized by a high velocity jet and pressure drop limited to the small central orifice. This
localized pressure drop is recovered once the flow from the two lateral orifices joins with the
central flow. Unlike the bileaflet prosthesis, the phenomenon of pressure drop and recovery is
not significantly observed in tilting disc valves due to the presence of relatively larger orifices.
Patient prosthetic mismatch (PPM) occurs in a normally functioning prosthetic valve when EOA
is inadequate with respect to the patient’s body surface area resulting in high velocity and
pressure gradients across the valve. PPM has been related to reduce the long term survival,
deterioration of functional class, poor regression of LV and acute cardiac events. To define
adequate patient prosthesis match, the indexed orifice area (IOA) should be more than or equal to
0.85 cm2/m
2 for aortic valve prosthesis
20. The other flow independent parameters that were used
to assess the aortic prosthetic valve function are contour of the velocity jet, AT, AT/ET and DVI.
Doppler measurements should be obtained in sinus rhythm at a sweep speed of 100 mm/sec over
1 to 5 cardiac cycles. For the calculation of DVI and EOA by CE, a double envelope
CWDwaveform is preferred over separate measurements of LVOT and prosthetic valve VTI
because the values are obtained from the same cardiac cycle and the chances of error are less21
.
Prosthetic aortic valve regurgitation
Prosthetic valve regurgitation jets may be physiological or pathological. The
physiologic regurgitation jets are usually mild and classified as: 1) Washing jets – seen where the
leaflets meet the strut at hinge points 2) Closing jet – jet originating at the site of contact between
15
the occluder and the annular metallic stent. Both are located inside the sewing ring and are
thought to prevent thrombi formation within the sewing ring and on the LV surface of the disc.
They are located within the sewing ring, usually of low velocity, homogeneous in color, less than
5 cm in length and regurgitant fraction will be < 15%. They vary depending on the type of
prosthesis. The pathological regurgitation jets can be intravalvular or paravalvular. The location
of paravalvular regurgitation is outside the sewing ring. Biological valves commonly have mild
degree of central regurgitation. The prevalence of paravalvular regurgitation jets ranges from 5 to
20 % immediately in the post-CPB period. Majority of them are benign in nature, are not
associated with hemodynamic instability and usually disappear after the administration of
protamine. The large central intravalvular jets are invariably pathological and originate due to
occluder mechanism malfunction attributed to different etiologies. Identification of exact
location and classification of the severity of pathological regurgitation jets requires multiplane
TEE imaging and Doppler evaluation. The integration of qualitative, quantitative and semi-
quantitative parameters should be used to assess and grade the severity of prosthetic valve
regurgitation (Table 3).
16
Table 3: Parameters for assessment of the severity of prosthetic aortic valve regurgitation5
ECHOCARDIOGRAPHIC PARAMETER
MILD AR
MODERATE AR
SEVERE AR
Prosthetic valve structure and motion
Biological or Mechanical
normal
Abnormal
Abnormal
LV size Normal mildly dilated Dilated
QUALITATIVE OR SEMI-QUANTITATIVE
DOPPLER PARAMETERS
AR Jet width to % LVOT diameter
AR jet density
AR Jet PHT (ms)
LVOT flow versus pulmonary blood flow
Flow reversal in the descending aorta during
diastole
≤ 25% 26 – 64% ≥ 65%
Faint Dense Very dense
> 500 200-500 < 200
Mild ↑ Intermediate Highly ↑
Absent or
early
diastolic
Intermediate holodiastolic
QUANTITATIVE DOPPLER PARAMETER
Regurgitant volume (ml/beat)
Regurgitant fraction (%)
< 30 ml 30 – 59 ml > 60 ml
< 30 % 30-50 % >50 %
Abbreviations: AR- Aortic regurgitation; PHT- Pressure half time; LVOT – Left ventricular
outflow tract
17
Prosthetic aortic valve stenosis
Prosthetic valve stenosis is usually detected during follow up period after the
surgery. Valve stenosis may occur due to thrombus, pannus formation or infective endocarditis.
Isolated prosthetic valve stenosis is rare in the intraoperative period. However, prosthetic valve
stenosis may sometimes be observed in the post-CPB period due to occluder malfunction
attributed to suture or tissue tag entrapment or structural manufacturing defects. TEE has become
an essential imaging modality for the intraoperative detection of prosthetic valve malfunction,
PPM and suboptimal surgical repair. Various factors such as mechanical ventilation, changing
loading conditions, inotropic and chronotropic medications and pacing of the heart may interfere
with the assessment of prosthetic valve function. Therefore, assessment of prosthetic valve
function in the perioperative period is a unique challenge for the echocardiographer. The
diagnosis of prosthetic valve stenosis should not be based on detection of high velocity and
pressure gradient because high flow rates or PPM may also produce significantly high velocity
flows. Conversely, false low gradients may occur in a patient with severe prosthetic valve
stenosis if there is a low cardiac output state. Therefore, the diagnosis and grading of prosthetic
valve stenosis should be made in an integrated and sequential way by analyzing various
echocardiographic parameters (Table 4) (Figure 2).
18
Table 4: Doppler parameters of prosthetic aortic valve function5
Doppler Parameter
Normal
Stenosis possible
Stenosis
significant
Peak velocity
< 3 m/s
3-4 m/s
> 4 m/s
Gradient mean
< 20 mm Hg
20 – 35 mm Hg
> 35 mm Hg
Doppler velocity index
≥ 0.3
0.29 – 0.25
< 0.25
Effective orifice area
>1.2 cm2
1.2 – 0.8 cm2
< 0.8 cm2
Acceleration time
<80 ms
80 – 100 ms
> 100 ms
Contour of velocity jet
early peaking,
triangular
Triangular to
intermediate
Symmetrical
rounded contour
19
Figure 2: Algorithm for evaluation of elevated peak prosthetic aortic jet velocity5
DVI ≥ 0.30 DVI 0.25 - 0.29 DVI< 0.25
Consider Prosthetic Aortic
valve stenosis with
1. Sub-valvular narrowing
2. Gradient underestimated
3. LVOT velocity improper
Normal Prosthetic
aortic valve
Prosthetic aortic
valve stenosis Improper
LVOT
velocity
Indexed orifice area
High flow
across valve
Patient Prosthesis
Mismatch
> 100 <100 > 100 <100
Jet Contour
AT
(ms)
))
PEAK VELOCITY OF PROSTHETIC AORTIC VALVE > 3 m/s
20
The prosthetic valves are assessed using TTE in the post-operative period.
However, the prosthesis is closely inspected with TEE during surgery. The intraoperative
Doppler measurement should serve as the reference guide for the evaluation of prosthesis during
the follow up studies.
Shapira et al 2studied the impact of post-CPB intraoperative TEE in valve
replacement surgeries. About 417 patient’s data, who underwent valve replacement surgeries
(bio-prosthetic or mechanical valves), was studied in a retrospective manner. About 501 heart
valves were inserted which included: 237 mitral, 221 aortic and 43 tricuspid. In 15 patients
(3.6%), post-CPB TEE has detected unanticipated pathologic findings and demanded immediate
surgical correction. The other findings picked up by post-CPB TEE were peri-valvular leak (8
patients), immobilized leaflets (4 patients), coronary ostia obstruction by aortic valve (2 patients)
and incompetent xenograft (1 patient). In 47 patients (11.3%), who were difficult to wean from
CPB, intraoperative TEE contributed to the evaluation of the problem and to its therapeutic
management. Prolonged removal of air under intraoperative TEE imaging was needed in 45
patients (10.8%). From the results, they came to a conclusion, that immediate post-CPB TEE has
an important diagnostic and therapeutic role in patients undergoing valve replacement surgeries
and it should be widely applied.
Qizilbash et al 22
had an updated review on the impact of perioperative TEE in
aortic valve replacement. They found that many studies have shown that intraoperative TEE has
made alterations in therapy from 10 % to more than 40%. Pre-CPB TEE can provide predictive
information, guide optimize hemodynamics and diagnose the prediction of PPM. Placement of
various CPB cannulae can be performed under the guidance of TEE. Post-CPB TEE verifies the
surgical repair and monitor the hemodynamics. The authors suggested that although according to
21
current guidelines TEE is a class IIa indication for aortic valve surgeries, it should be routinely
used in aortic valve replacements (AVR).
Daniel et al 23
did a retrospective study on 140 prosthetic valves implanted at
mitral (89), aortic (45) and tricuspid (6) positions in 116 patients using transthoracic and
transesophageal echocardiography. TEE was found to be consistently better than the TTE during
the evaluation of structural abnormalities of tissue valves in the mitral and aortic positions and
localization and quantification of prosthetic valve regurgitation. Six patients had left atrial or left
atrial appendage thrombus and it was detected only by TEE in 5 patients. The authors concluded
that TEE should be complimentary to TTE during the evaluation of patients with prosthetic valve
dysfunction or during the follow-up of older tissue valves.
Daniel et al 24
compared the transthoracic and transesophageal echocardiography
for detection of prosthetic and bio-prosthetic valve abnormalities in the mitral and aortic
positions. They studied 148 prosthetic valves in 126 patients by TTE and TEE for detection of
abnormalities. Prosthetic valve endocarditis and thrombi were diagnosed by TTE in 36% and
13% respectively. But TEE identified these lesions in 82% and 100% respectively. Overall, they
found that TTE had 57% sensitivity and 63% specificity, whereas TEE had 86% sensitivity and
88% specificity in detecting the prosthetic valve endocarditis, thrombi and other morphologic
abnormalities.
Alton et al25
studied the normal characteristics of 47 Starr-Edwards prosthetic
heart valve implanted in 37 patients using TEE. Using this data, they compared usefulness of
TEE with TTE in detecting the valve abnormalities. They found that TEE is superior to TTE in
detection of thrombus, severity of mitral regurgitation and vegetation and abscess formation in
infective endocarditis. They concluded that TEE has a unique efficacy in detection of prosthetic
22
valve dysfunction and it is also of great value in assessing the severity of prosthetic valve
regurgitation and response to treatment when TTE becomes inadequate.
Levy et al26
compared the Doppler profile in patients undergoing AVR between
post-CPB intraoperative TEE and post-operative TTE (after two to four months of surgery).
Thirty one patients were included in the study. The valves studied were Freestyle stentless aortic
root bio-prosthesis (23 patients), Medtronic-Hall tilting disc mechanical valve (4 patients),
mosaic bio-prosthesis (3 patients) and Carpentier Edwards Perimount pericardial valve (1
patient). On echocardiographic evaluation of these patients, they reported that there were no
significant differences in Doppler pressure gradients or LVEF among these patients at the two
time intervals as mentioned above. However, there was no obvious correlation in the Doppler
mean gradients at the two time periods (R2 = 0.09; p = 0.11); for peak gradient the correlation
was extremely weak but statistically significant (R2 = 0.17; p = 0.02). The prediction of high
mean gradient obtained on TTE during follow up period based on reference values provided by
intraoperative TEE was also poor (0.63-area under curve). They concluded that gradients
measured by intraoperative TEE do not correlate with those measured by TTE during the follow-
up period. The intraoperative TEE also has no utility in predicting a high mean gradient observed
2-4 months after the surgery.
The functioning of a prosthetic aortic valve in the intraoperative period is assessed
by TEE using M mode, 2 dimensional echo, color Doppler and spectral Doppler methods.
Assessment of flow across the prosthetic valve using spectral Doppler interrogation remains an
invaluable component of complete prosthetic valve examination.
23
Weinstein et al27
analyzed the M-mode, 2DE and Doppler characteristics of St.
Jude medical valves implanted at aortic and mitral position in 23 asymptomatic patients.
Findings were compared with the echocardiographic characteristics of native valves. The
outcome of the study suggested that the morphological spectra of mitral and Doppler flow were
analogous between the native and the prosthetic valves, unlike the values of the peak and mean
velocities, which were higher in prosthetic valves. M mode and 2D echocardiography were of no
value in quantitative estimation of prosthetic valve function. Color Doppler studies of prosthetic
valves demonstrated 4 cases of paravalvular leaks which were not identified by M mode or 2D
echo. The authors concluded that Doppler echocardiography is reliable and helpful in providing
quantitative data about the flow profiles across the St. Jude prosthetic valves and is valuable for
discovering the prosthetic valve dysfunction.
Different parameters ascertained on spectral Doppler interrogation of prosthetic
aortic valve include peak velocity, peak gradient, mean gradients, EOA, stroke volume, DVI and
AT. Studies differ in their conclusion regarding which Doppler parameter can provide precise
information on prosthetic valve function and which among them can be more pertinent in the
perioperative period.
Panidis et al28
performed Doppler echocardiography in 136 patients with
normally functioning prosthetic valves at aortic, mitral and tricuspid positions. The valves
studied include St. Jude (82), Bjork Shiley (18), Beall (13), Starr Edwards (7) and tissue valve
(16). The results showed that in aortic position, St. Jude valve had a lower peak velocity, lower
peak and mean gradient than other valves whereas in mitral position, the St. Jude valves
provided a larger EOA in comparison to other prosthetic valves. Insignificant regurgitation was
detected in all the implanted valves in both mitral and aortic position. They also included 17
24
patients with proven malfunctioning prosthetic valves in their study. The malfunctioning valves
consisted of St. Jude (4), Bjork-Shiley (2), Beall (4) and tissue valves (7). They found that
Doppler echocardiography correctly identified the malfunctioning valve in all patients, except 2
who had a Beall valve. They concluded that Doppler echocardiography is a useful technique for
the detection of prosthetic valve dysfunction and the St. Jude medical prosthesis appears to be
associated with ideal hemodynamic parameters and valve features compared to Bjork-Shiley and
other tissue valves.
Badano et al29
prospectively studied 76 consecutive patients implanted with
Bicarbon bileaflet prosthetic valves at mitral and aortic positions to describe the normal Doppler
flow characteristics of these valves and compared them with those obtained from St. Jude
medical valves. They did not find any significant difference in the trans-prosthetic gradients,
pressure half time and EOA among the valves implanted at mitral position. But in aortic valve
prosthesis, they observed a significant decrease in the transprosthetic gradients and increase in
the effective orifice areas as the size of the prosthetic valves increased. EOA estimated by
continuity equation was found to have statistically significant correlation with the sizes of the
prosthetic valves than the peak and mean gradients. Also the trans-prosthetic gradients and EOA
did not differ significantly between Bicarbon and St. Jude Medical prosthetic valves among
different sizes of aortic prosthetic valves.
Rajani et al30
in their updated review summarized the normal Doppler
echocardiographic parameters of mechanical valve, bio-prosthetic valve and homograft
implanted in aortic position. About 129 studies were reviewed and Doppler parameters such as
peak velocity, peak and mean pressure gradient and EOA calculated by CE were noted. They
found that in the order of degree of obstructive nature, caged-ball valve prosthesis occupied the
25
top-most position which was trailed by the stented porcine and single tilting-disc valves. The
stented bovine pericardial valves and intraannular bileaflet mechanical valves were slightly less
obstructive. Stentless valves and reduced-cuff bileaflet valves were similar and appeared less
obstructive than the valves mentioned above. Homo-grafts were found to be least obstructive.
They suggested that every study designed to evaluate the prosthetic valves should provide details
of peak velocity, peak and mean pressure gradients using the modified Bernoulli equation, and
also the EOA using the standard form of CE. If any new valve design is introduced, normal
echocardiographic ranges should be published as a reference guide to the clinicians. A baseline
echocardiogram should be done in every case as soon as the valve is implanted to create a
‘finger-print’ as a reference for future studies.
Chafizadeh et al 18
studied 67 patients receiving St. Jude Medical valves in aortic
position. The objective of the study was to evaluate the utility of CE for the noninvasive
assessment of prosthetic aortic valve function. The maximal gradients derived by the Doppler
ranged from 9 to 71 mm Hg. The continuity equation derived EOA of the prosthetic aortic valve
ranged between 0.73 cm2 and 4.23 cm
2 for 19-mm and 31-mm valves respectively and it
described the flow characteristics of various sizes of valves better than the gradients alone. The
mean DVI 0.41±0.09 and it was independent of the valve size. They came to a conclusion that
CE can be used for the assessment of prosthetic St. Jude valves implanted at aortic position. It
provides a better assessment than the use of gradients alone for the evaluation of prosthetic valve
function.
PPM is a frequent problem in patients undergoing aortic valve replacement when
the EOA of the implanted prosthetic valve is less than that of a native valve with respect to body
surface area (BSA). It produces hemodynamic consequences in the form of high trans-prosthetic
26
flow gradients in a normally functioning prosthetic valve. The severity of PPM is classified
based on indexed orifice area of the prosthetic valve with iEOA ≥ 0.85 cm2/m
2 as normal, 0.65-
0.85 cm2/m
2 as moderate PPM and < 0.65 cm
2/m
2 as severe PPM
31, 32. The presence of PPM has
a major short term as well long term impact on the hemodynamics, recovery from left ventricular
hypertrophy, functional capacity, morbidity and mortality.
Tasca et al33
studied the midterm impact of PPM on cardiac events and overall
mortality after aortic valve replacement. About 315 patients with isolated aortic stenosis were
studied consecutively and the indexed EOA for each size and type of prosthesis was calculated
after aortic valve replacement. Forty seven per cent of patients had PPM that correlated well with
cardiac events and overall mortality. Patients with PPM had significantly less overall survival
and cardiac-event free survival rates than those with no PPM. They concluded that PPM is an
independent predictor of midterm mortality and cardiac events in patients undergoing AVR It
can be avoided by taking preventive measures at the time of surgery.
Mohty et al 34
studied the impact of PPM on long-term survival in 388 patients
who underwent AVR with small (19 or 21 mm) St. Jude Medical prosthetic valves. They found
that patients with severe PPM (iEOA ≤ 0.60 cm2/m
2) had a significantly less 5-year and 8-year
survival rates than those moderate (iEOA 0.60 – 0.85 cm2/m
2) or no PPM (iEOA ≥ 0.60 cm
2/m
2).
Also the mortality rate and the incidence of congestive heart failure were higher in patients with
severe PPM compared to those with moderate or no PPM.
Mohty et al35
in another study evaluated the effect of PPM on late survival and the
survival modulation by age, body mass index (BMI) and pre-operative LV function. About 2,576
patients who underwent AVR were included in the study. They found that severe PPM increases
the late mortality only in patients < 70 yrs of age or BMI < 30 kg/m2 or an LV ejection fraction
27
(LVEF)< 50%. In patients with moderate PPM the late mortality was increased with poor LV
function whereas the prognosis was normal with preserved LV function.
Head et al36
performed a meta-analysis of observational studies to study the
impact of PPM on long-term survival after AVR. Thirty four studies were included comprising
27,186 patients and 133,141 patient-years. Analysis by severity of PPM demonstrated that both
moderate and severe PPM increased all-cause mortality and cardiac-related mortality. They
concluded that PPM is associated with an increase in all-cause and cardiac-related mortality over
long-term follow-up.
Pibarot et al37
did a study on 396 patients to predict the PPM at the time of
surgery using three indices, viz. indexed internal geometric area, valve size and projected
indexed orifice area. The results were compared with the Doppler derived mean gradients and
IOAafter surgery. Their results showed that PPM as well as resting and exercise postoperative
gradients can be accurately predicted by the projected indexed orifice area calculated at the time
of surgery.
The available options to avoid or reduce the severity of PPM during aortic valve
replacement include (1) Implanting an another type of prosthetic valve with larger EOA (2)
Aortic root enlargement and placing a larger valve (3) accepting PPM by consideration of other
clinical conditions
Ardal et al38
evaluatedthe long-term results of posterior aortic root enlargement
(ARE) in 124 patients who underwent AVR with ARE. The overall operative mortality was
6.4%. Late deaths were 5.4%. The predictors for late mortality were infective endocarditis and
low cardiac output syndrome. Permanent pacemaker was needed in 3.2% patients. They
28
concluded that posterior ARE has no additional risk and the long-term survival rates as well as
complication-free survival rates are acceptable.
Coutinho et al 39
analyzed the short-term outcome of ARE with adverse events
and death as end points. About 218 patients with small aortic root who underwent AVR with
ARE were compared with those with small aortic root with AVR alone. There was no much
significant difference in hospital mortality, need of inotropic support, chest tube drainage and
complication rates. The peak and mean pressure gradients were significantly lower in patients
with root enlargement. About 11% of patients who underwent ARE had moderate PPM but
severe PPM was not present in any of them. The authors suggested that ARE does not affect the
operative risk or short-term outcome and it can be done in a safe and reproducible manner.
The sensitivity and specificity of PPM detection by intraoperative TEE has not
been reported. If studies prove that PPM can be detected accurately by intraoperative TEE, then
the further decisions whether to accept the PPM or to perform ARE or to select appropriate size
and type of prosthesis can be taken on the operation table in the pre-CPB period. Also the
sensitivity and specificity of preoperative TEE in detecting PPM can be ascertained in a
retrospective manner in the post-CPB period by the calculating EOA using TEE.
29
AIMS AND OBJECTIVES
30
AIMS AND OBJECTIVES
Hypothesis
We hypothesize that:
1. AVR using CHVP provides satisfactory hemodynamic conditions after termination of CPB.
2. Examination of tilting disc CHVP with TEE in the post-CPB intraoperative period will reveal
echo characteristics and Doppler flow profile which are compliant with the criteria set by the
ASE to describe a normal functioning aortic valve prosthesis.
Aims and objectives
Our primary objectives were:
1. To analyze the intraoperative hemodynamic performance of CHVP at aortic position using
clinical parameters and TEE.
2. To define the intraoperative echocardiographic characteristics and flow profile of CHVP on
2D and color Doppler examination.
3. To study the intraoperative spectral Doppler parameters of CHVP.
4. To compare the intraoperative Doppler parameters among different sizes of CHVP.
Our secondary objectives were:
1. To compare the intraoperative TEE Doppler profile with postoperative TTE Doppler profile
performed 48 hours after surgery and 3 months after surgery
31
2. To compare the Doppler profile of CHVP in our study with the published data of St. Jude
Medical Bileaflet mechanical valve prosthesis in common use
3. To analyze the detection of PPM of CHVP by intraoperative TEE.
32
MATERIALS AND
METHODS
33
MATERIALS AND METHODS
After obtaining approval from the Technical Advisory Committee (TAC) [SCT-
/S/2014/311], Institutional Ethics Committee (IEC) [IEC registration no - ECR/189/Inst
/KL/2013], and after registering the trial in Clinical Trials Registry – India (CTRI)[Reg no -
CTRI/2016/08/007141] this prospective, observational study was carried out in a tertiary referral
Centre (SCTIMST) which annually performs more than 300 heart valve replacements.
Inclusion Criteria
Adult patients subjected to elective AVR using CHVP without repair or replacement of
other valves.
Exclusion Criteria
Patients < 18 years of age and > 60 years of age
LVEF< 40%
Mitral regurgitation – moderate-to-severe or severe
Mitral stenosis - moderate-to-severe or severe
After weaning from CPB in first attempt, patients requiring re-institution of CPB, due to
inadequate surgical results like severe prosthetic aortic valve regurgitation and inadequate
motion of occluder disc.
Concomitant repair or replacement of other valves
Patients having significant coronary artery disease with or without requirement for
coronary artery bypass grafting; atrial septal defect; ventricular septal defect; or any
34
significant pathology that would affect hemodynamic parameters and echocardiographic
profile of the prosthetic valve.
Re-do aortic valve replacement
Contraindication to TEE probe placement like esophageal strictures, esophageal varices,
esophageal tumors, gastric ulcer,previous esophageal surgery, esophageal diverticulum,
tracheoesophageal fistula, previous bariatric surgery, hiatus hernia, large descending
thoracic aortic aneurysm, unilateral vocal cord paralysis, post‑ radiation therapy
Patient refusal to participate in the study
Inability to image the prosthesis satisfactorily to interpret the results
Emergency surgeries.
STUDY PROTOCOL
A total of 40 consecutive patients fulfilling the inclusion criteria were selected as
subjects for the study. Patients were educated about the study in presence of a witness. The
witness was permitted to counter question the patient whether he/she really understood the
proposed study, of which he/she would be a participant. An informed consent form was signed
by patient or relative of the patient as per the Institute protocol.
In the operation room (OR), an adult-size TEE probe was inserted after induction
of general anesthesia and the heart was inspected using an ultrasound system (IE 33, Philips
Ultrasound, Bothell, USA). In the pre-CPB period, hemodynamic parameters and
echocardiographic data were recorded which included peak velocity, peak and mean pressure
gradients, aortic valve area by planimetry and CE, aortic regurgitation severity.
35
Left atrial (LA) anteroposterior diameter was measured in Midesophageal long
axis view (ME LAX) view. LV chamber dimensions were measured in systole and diastole at the
level of insertion of chords onto the mitral valve leaflets, using 2D-TEE in Transgastric 2
Chamber (TG 2C) view. LV wall thickness was measured in systole and diastole using
Transgastric mid-papillary short axis view. LVEF was measured by Simpson’s method using X-
plane view. The aortic valve was examined for the presence of calcification of the leaflets and
annulus. The aortic annulus was measured using Midesophageal aortic valve long axis view (ME
AV LAX). The size of ascending aorta at the level of right pulmonary artery was also measured.
Other valves were examined to rule out any concomitant disease.
CPB was established after adequate heparinisation and aorta was cross-clamped.
Antegrade blood cardioplegia was infused into the aortic root or into the coronary ostia (in the
presence of severe AR) to achieve diastolic arrest of the heart. Diseased aortic valve was excised
and appropriate Chitra heart valve prosthesis (CHVP) was implanted. After implantation of the
CHVP in aortic position, cross clamp was removed and the patients were weaned off from CPB.
Patients were adequately re-warmed and inotropic infusions (as per the Institute protocol) were
commenced before weaning the patient. Heart was examined using TEE before and after the
administration of protamine. Echo data was archived in the hard disc of the echo machine, which
was retrieved later on compact disc. CHVP was re-evaluated using transthoracic
echocardiography 48 hours after the surgery (TTE1) when inotropes were weaned off and stable
hemodynamic condition was achieved. Peak velocity, peak gradient, mean gradient and heart
rate were noted. The patients were kept on follow-up and the above mentioned Doppler
echocardiographic parameters were once again measured by TTE after 3 months (TTE2).
36
EVALUATION OF CHVP AT AORTIC POSITION.
Two dimensional and color Doppler evaluation.
The prosthetic valve was evaluated for valve seating, free leaflet motion, and
angle of opening using intraoperative 2D TEE. The prosthesis was subjected to color Doppler
imaging to detect the presence of any paravalvular leaks and to ascertain the degree of
intravalvular regurgitation before and after the administration of protamine (Figure 3A, 3B& 4).
Spectral Doppler evaluation of aortic valve prosthesis
TEE view in which the Doppler beam could be aligned parallel to the flow of the
prosthetic valve was selected for Doppler evaluation [Transgastric long axis view (TG LAX) and
deep transgastric 5 chamber view (deep TG 5C)]. The following parameters were assessed to
evaluate the prosthetic valve in the aortic position: peak velocity, peak gradient, mean gradient,
AT, AT/ET ratio, contour of the velocity jet, EOA by CE, and DVI.
Major aperture was identified on Color Doppler in TG LAX as well as deep TG
5C views and CWD profile was obtained across the aperture. CWD produced a classical double
envelope VTI pattern across the prosthetic outflow, from which maximal velocity, peak gradient,
mean gradient, acceleration time, ejection time, LVOT VTI, prosthetic valve VTI, were
measured(Figure 5A &5B). EOA of the prosthetic aortic valve was calculated using the CE, as
stroke volume through the LVOT divided by the VTI of the prosthetic aortic valve. Regular R-R
intervals were confirmed whenever EOA or DVI were measured using more than one cardiac
cycle. Peak velocity, peak gradient and mean gradient were obtained in the post-operative period
on TTE in apical 5C view and then these values were compared with the parameters obtained in
37
the intraoperative period. The actual (geometric) orifice area (AOA) published by the
manufacturer was noted.
Projected EOA, projected IOA and required valve size
To avoid PPM, projected EOA was calculated by multiplying BSA of the patient
with 0.85 before surgery. The required size of CHVP to provide the projected EOAwas derived
in the pre-CPB period from the results published by Namboodiri et al14
which were used as
reference values. Projected indexed orifice area (IOA) was calculated from the mean EOA of the
implanted CHVP valves (taken from the published study by Namboodiri et al14
)divided by the
BSA of the patient.
38
STATISTICAL ANALYSIS
All data were entered in Microsoft excel version 2010.The statistical mean and
standard deviation were derived for the continuous variables. The prosthetic valves were divided
into five groups based on their size. Pearson’s correlation coefficient was used for all correlation
evaluations (1. between a Doppler parameter and the size of the CHVP; 2. between
intraoperative TEE and postoperative TTE gradients; 3. between TEE IOA and projected IOA) [r
value: 0 to 0.35 - poor/weak correlation, 0.36 to 0.55 - good correlation and > 0.55 -
significant correlation]. Doppler parameters of post-CPB intraoperative TEE were compared
with TTE parameters obtained 48 hours after surgery and 3 months after surgery, using the
Paired t- test and a p-value < 0.05 was considered significant. Intraoperative TEE CHVP
Doppler parameters were compared with TTE parameters of other mechanical valves from
published data using independent t-test with unequal variances. Fisher’s exact test was used to
compare the non-parametric data for the prediction of PPM by intraoperative TEE.
All statistical analysis were performed using Graphpad Instat software
39
RESULTS AND
OBSERVATIONS
40
RESULTS AND OBSERVATIONS
A total of 40 patients who underwent aorticCHVP replacement without
concomitant repair or replacement of other heart valves were included in the study. They were
divided into 5 groups based on the various sizes of replaced valves. The valve sizes and the
number of patients in each group were 19, 21, 23, 25, 27 mm and 8, 15, 9, 3 and 5 respectively.
The demographic profile and preoperative clinical features of all the patients are portrayed in
Table 5
Table 5: Demographic profile and preoperative clinical features of patients
Abbreviations: BSA:–Body Surface Area; NYHA: - New York Heart Association;
AS: - aortic stenosis; AR: - aortic regurgitation
Total number of patients (n = 40)
Age (years) 42.02 ± 11.85
Sex Male
Female
33 (82.5%)
7 (17.5%)
Height (cm) 163.79 ± 8.93
Weight (kg) 62.50 ± 10.46
BSA (m2) 1.67 ± 0.15
Diagnosis
Degenerative
Rheumatic
Bicuspid
21 (52.5%)
10 (25%)
9 (22.5%)
Predominant AS
Predominant AR
21 (52.5%)
19 (47.5%)
NYHA Class
Class II
Class III
23 (57.5%)
17 (42.5%)
Rhythm Sinus 40
41
Table 5 shows that the average age of the study subjects involved in the study was 42.02 ± 11.85
years. Males were in a larger proportion (82.5%) compared to the females (17.5%). The most
common pathology was degenerative disease (52.5%), followed by rheumatic and bicuspid aortic
valve. Both stenosis and regurgitation lesions were prevalent among the patients. Majority of the
patients presented with NYHA class II symptoms (57.5%), whereas 42.5% patients presented
with NYHA class III symptoms. All the 40 study subjects were in normal sinus rhythm.
Table 6:- Distribution of valve sizes and the number of patients in each group.
Table 6 shows distribution of five different sizes of CHVP implanted at aortic position. Majority
of the patients were implanted with 21 mm valve (37.5%). The 19 mm and 23mm valves
wereimplanted in 20% and 22.5% of patients respectively. This was followed by 27 mm valve
(12.5%). A small proportion of patients (7.5%) received 25 mm valve.
Valve Size
Number of patients
Percentage
19 mm 8 20 %
21 mm 15 37.5 %
23 mm 9 22.5 %
25 mm 3 7.5 %
27 mm 5 12.5 %
Total 40
42
Table 7:Pre-CPB TEE observations
Echocardiographic parameters (intraoperative pre-CPB TEE)
LVID (mm)
Diastole
50.96 ± 10.63
LVID (mm)
Systole
35.73 ± 9.00
Ejection fraction (%)
58.47 ± 7.73
LA size (mm)
40.61 ± 8.22
Aorta size (mm)
28.83 ± 3.58
Septal wall
(mm)
Systole
18.69 ± 3.63
Diastole
15.97 ± 3.44
Inferior wall
(mm)
Systole
17.24 ± 2.99
Diastole
14.62 ± 2.93
Abbreviations: TEE: – Transesophageal echocardiography; CPB: – Cardiopulmonary bypass;
LVID: – Left ventricular internal diameter; LA: – left atrium; LV: – Left ventricle
Table 7 shows the intraoperative TEE observations during the pre-CPB period. LV function was
found to be good in the study subjects with an average ejection fraction of 58.47 ± 7.73 %.
Average LV dimensions were suggestive of mild LV dilatation. None of the patients had dilated
ascending aorta. Septal wall thickness > 20 mm was found in 14 patients; however, none had any
Systolic anterior motion (SAM) potential and hence septal resection was not needed.
43
All prosthetic valves were evaluated by TEE in the post-CPB period after the
administration of protamine. 2D TEE for degree of leaflet mobility, angle of leaflet opening, and
stability of valve seating; color Doppler examination for any paravalvular or intravalvular leaks;
and spectral Doppler assessment for peak velocity, peak and mean gradients, AT, AT/ET, DVI
and EOA by continuity equation were performed (Figure 3A, 3B,4,5A and 5B).
None of the patients had restriction of leaflet mobility or abnormal seating of the
valve. Angle of leaflet opening was 60 to 70 degrees in all patients. A trivial paravalvular leak
was noticed in two patients which disappeared after the administration of protamine.
Figure 3:(A) ME AV short axis view showing normal seating of CHVP, (B) Color Doppler in
ME AV long axis view showing free flow across the CHVP in open position (yellow arrow)
44
Figure 4: Color Doppler across the CHVP in deep TG 5C view showing washing jets at hinge
points (white arrow)
Figure 5: (A) The CHVP evaluated in TG 5-Ch view using CWD depicts double envelope
pattern of VTI; the inner dense and outer semi-dense envelope representing the LVOT and
prosthetic valve VTI respectively. Measured parameters including peak velocity, peak and mean
pressure gradients, DVI and effective orifice area are shown in the figure (B) measurement of
acceleration time (AT) which is the time required for the flow to reach the peak velocity from
baseline
45
Doppler parameters evaluated from intraoperative TEE showed that the flow
dependent parameters such as peak velocity, peak and mean gradient decreased with increase in
the valve size while the flow independent parameters such as AT, DVI, AT/ET remained
constant and within the normal range. EOA which is a flow independent parameter increased
with increase in valve size. (Table 8 and Figure 6)
Figure 6:-Spectral Doppler parameters of various sizes of CHVP studied
Figure 6:depicts Doppler parameter values (Y-axis) obtained for varioussizes of CHVP (X-axis).
Peak velocity, peak gradient and mean gradient decreased significantly with increase in the valve
size, whereas the flow independent parameters such as DVI, AT and AT/ET ratio showed no
significant change with increase in the valve size. EOA by CE increased with increase in valve
size. The peak velocity and the pressure gradients were in higher normal range for small-sized
valves(19 and 21 mm).
46
Table 8:-Intraoperative post-CPB Doppler parameters of various sizes of aortic CHVP and their
correlation with the valve size
Table 8: peak velocity, peak and mean gradients showed significant negative correlation with
increase in the size of CHVP; EOA and IOA had significant positive correlation with the size of
the prosthesis; DVI, AT and AT/ET had a weak correlation with the size of the prosthesis; Heart
rate among the groups did not vary significantly. [Abbreviations: - DVI: - Doppler velocity
index; AT: – Acceleration time; AT/ET: -Acceleration time/ Ejection time ratio; EOA: -
effective valve area; IOA: - Indexed orifice area; CE: - continuity equation]
Pearson correlation co-efficient [r]:- positive value denotes direct correlation whereas negative
value signifies inverse correlation. (0 to 0.35-poor/weak correlation, 0.36 to 0.55- good
correlation, > 0.55 significant correlation).
19 mm
21mm
23 mm
25 mm
27 mm
#CORRELATION
Peak velocity
(m/sec)
2.91±0.13
(2.78 – 3.2)
2.56±0.32
(1.58 – 2.9)
2.47±0.30
(1.87 – 2.78)
2.19±0.28
(1.87 – 2.4)
1.86±0.24
(1.6 – 2.03)
r = - 0.7610
p <0.0001
Peak Gradient
(mm Hg)
34.10±3.08
(31 – 41)
26.92±5.93
(10.1 –35.2)
24.93±5.61
(14 – 30.92)
19.33±4.72
(14 – 23.1)
13.3±3.69
(10.2 –17.6)
r = - 0.7714
p <0.0001
Mean Gradient
(mm Hg)
19.97±1.53
(18.1 – 23)
15.43±3.86
(5 – 20.2)
13.85±3.18
(8.1 – 18.6)
9.66±1.52
(8 – 11)
7.3±1.86
(5.1 – 9.6)
r = - 0.7888
p < 0.0001
Heart rate 85.12±10.97
(64 – 103)
84.8±8.58
(69 – 90)
87.77±9.85
(74 – 100)
87.33±8.08
(80 – 96)
87.8±4.14
(84 – 94)
r = 0.1310
p = 0.4203
AT
(msec)
69.87±12.28
(52 – 95)
66.4±9.14
(40 – 77)
63.44±15.03
(41 – 78)
63.33±4.72
(58 – 67)
62.6±6.98
(52 – 70)
r = - 0.2170
p = 0.1787
AT/ET
0.28±0.04
(0.21 – 0.34)
0.26±0.04
(0.17 –0.38)
0.26±0.02
(0.2 – 0.31)
0.25±0.04
(0.21 -0.28)
0.25±0.03
(0.21 – 0.3)
r = - 0.2084
p = 0.1968
DVI
0.38±0.08
(0.3 -0.5)
0.42±0.06
(0.34 -0.5)
0.40±0.08
(0.3 -0.5)
0.46±0.05
(0.4 -0.5)
0.46±0.14
(0.4 -0.5)
r = 0.3493
p = 0.0271
EOA by CE
(cm2)
1.35±0.21
(0.96 – 1.61)
1.61±0.19
(1.22 –1.98)
2.04±0.14
(1.75 – 2.24)
2.19±0.13
(2.12 –2.35)
2.44±0.04
(2.4 -2.51)
r = 0.9010
p = <0.0001
IOA (cm2)
0.87±0.08
(0.78 – 0.95)
0.94±01
(0.73 – 1.1)
1.16±0.08
(1.08 – 1.3)
1.19±0.11
(1.1 – 1.3)
1.38±0.12
(1.2 – 1.5)
r = 0.8381
p = <0.0001
47
Figure 7: Correlation between peak velocity, peak gradient and mean gradient with the different
sizes of aortic CHVP
The flow dependent parameters such as peak velocity (r = -0.7610), peak gradient
(r = -0.7714) and mean gradient (r = -0.7888) showed significant inverse relation with the
increase in the size of the prosthesis. Smaller sized valves (19 and 21 mm) in some patients
displayed higher mean gradients (> 20 mm Hg) without affecting hemodynamic condition.
-10
0
10
20
30
40
1
1.5
2
2.5
3
3.5
4
4.5
5
5.5
6
17 19 21 23 25 27 29
Pea
k a
nd
Mea
n G
rad
ien
t (m
m H
g)
Pea
k V
eloci
ty (
m/s
ec)
Size of Chitra Heart Valve Prosthesis
Peak Velocity (m/sec) Peak Gradient (mm Hg) Mean Gradient (mm Hg)
Linear (Peak Velocity (m/sec)) Linear (Peak Gradient (mm Hg)) Linear (Mean Gradient (mm Hg))
r = - 0.7610
p < 0.0001
r = -0.7714
p < 0.0001
r = - 0.7888
p < 0.0001
48
Figure 8: Correlation between Doppler velocity index, AT/ET, Acceleration time and heart
rate with the different sizes of aortic CHVP
DVI (r = 0.3493), AT/ET ratio (r = -0.2084), acceleration time (r = - 0.2170) and
heart rate (r = 0.1310) displayed poor correlation with the increase in valve size. Heart rate was
maintained within the average range of 70 to 85 per minute during the measurement of Doppler
parameters.
0
20
40
60
80
100
120
0.1
0.3
0.5
0.7
0.9
1.1
1.3
1.5
17 19 21 23 25 27 29
Acc
eler
ati
on
Tim
e (m
s) &
Hea
rt R
ate
per
min
Dop
ple
r V
eloci
ty I
nd
ex &
AT
/ET
Size of Chitra Heart Valve Prosthesis
Doppler velocity index AT/ET Acceleration Time (ms)
Heart Rate Linear (Doppler velocity index) Linear (AT/ET)
Linear (Acceleration Time (ms)) Linear (Heart Rate)
r = 0.1310
p = 0.4203
r = - 0.2170
p = 0.1787
r = 0.3493
p = 0.0271
r = -0.2084
p = 0.1968
49
Figure 9: Correlation between the effective orifice area and indexed orifice area with the
different sizes of aortic CHVP
The effective orifice area and the indexed orifice area calculated by continuity equation
increased significantly with increase in the size of the CHVP depicting a significant positive
correlation (r = 0.9010 and r = 0.8381 respectively).
[r – Pearson correlation co-efficient: positive value signifies direct correlation and values close
to 1 indicates significant correlation.]
0
0.5
1
1.5
2
2.5
3
3.5
4
0
0.5
1
1.5
2
2.5
3
17 19 21 23 25 27 29
Ind
exe
d O
rifi
ce A
rea
(cm
2/m
2 )
Effe
ctiv
e O
rifi
ce A
rea
(cm
2)
Size of Chitra Heart Valve ProsthesisEffective Orifice Area (cm2) Indexed Orifice Area (cm2/m2)
Linear (Effective Orifice Area (cm2)) Linear (Indexed Orifice Area (cm2/m2))
r = 0.9010
p < 0.0001
r = 0.8381
p < 0.0001
50
Table 9:- Comparison of Doppler parameters between intraoperative TEE and postoperativeTTE
on 3rd
post-operative day (TTE1).
Table 9: The intraoperative TEE Doppler parameters and heart rate were compared with the TTE
data (TTE1) on 3rd
postoperative day. The intraoperative peak velocity and pressure gradients
were slightly higher with all valve sizes except for 27 mm valve where the postoperative
gradients were higher, although there was no statistical difference among the parameters. Heart
rate obtained at different time periods had no statistically significant difference.
CHVP
Peak velocity
(m/sec)
Peak gradient
(mm Hg)
Mean gradient
(mm Hg)
Heart rate
per min
19 mm
TEE 2.91±0.13 34.10±3.08 19.97±1.53 85.12±10.97
TTE1 2.81±0.21 30.25±6.29 18.12±4.15 84.12±10.17
p value 0.2567 0.1298 0.2498 0.8328
21mm
TEE 2.56±0.32 26.92±5.93 15.43±3.86 84.8±8.58
TTE1 2.46±0.27 25.2±5.21 14.8±3.18 84.13±8.15
p value 0.1821 0.2083 0.5198 0.8309
23 mm
TEE 2.47±0.30 24.93±5.61 13.85±3.18 87.77±9.85
TTE1 2.23±0.35 20.88±6.64 12.17±4.26 84.33±9.05
p value 0.0680 0.0949 0.2775 0.2950
25 mm
TEE 2.19±0.28 19.33±4.72 9.66±1.52 87.33±8.08
TTE1 2.06±0.15 18.0±2.64 10±1.73 87±3.00
p value 0.2490 0.3828 0.4226 0.9388
27 mm
TEE 1.80±0.24 13.3±3.69 7.3±1.86 87.8±4.14
TTE1 2.02±0.13 16.8±2.58 10.12±1.33 79.4±9.58
p value 0.2582 0.2696 0.1087 0.2190
51
Figure 10:Correlation between the intraoperative TEE and 3rd
postoperative day TTE1
Doppler parameters of CHVP
Peak velocity (r = 0.7154), peak gradient (r = 0.6883) and mean gradient (0.6436) assessed by
transthoracic echocardiography on 3rd
postoperative day (TTE 1) showed a significant direct
correlation with the intraoperative Doppler parameters measured by transesophageal
echocardiography, suggesting that the values of Doppler parameters obtained on intraoperative
TEE strongly predict the postoperative values of Doppler parameters on TTE examination.
[r – Pearson correlation co-efficient: positive value signifies direct correlation and values close
to 1 indicates significant correlation.]
5
10
15
20
25
30
35
40
1.5
3
1 2 4 8 16 32 64
3rd
Po
sto
pe
rati
ve d
ay (
TTE1
) -
Pe
ak a
nd
me
an g
rad
ien
t
3rd
Po
sto
pe
rati
ve d
ay (
TTE1
) -
Pe
ak v
elo
city
Intraoperative TEE
Peak Velocity (m/sec) Peak gradient (mm Hg)
Mean Gradient (mm Hg) Linear (Peak Velocity (m/sec))
Linear (Peak gradient (mm Hg)) Linear (Mean Gradient (mm Hg))
r = 0.7154
p < 0.0001
r = 0.6883
p < 0.0001
r = 0.6436
p < 0.0001
52
Table 10:- Comparison of Doppler parameters between intraoperative TEE and postoperative
TTE after 3 months of surgery (TTE2)
Table 10 reveals that the values for peak velocity, peak gradient and mean gradient reduced as
the size of CHVP increased from 19 mm to 27 mm. Doppler parameters were not statistically
different for the same size valves when measured in the intraoperative period and 3 months after
the surgery. Heart rate remained in the same range among these patients in the post-CPB period
and 3 months after surgery.
CHVP
Peak velocity
(m/sec)
Peak gradient
(mm Hg)
Mean gradient
(mm Hg)
Heart rate
per min
19 mm
TEE 2.91±0.13 34.10±3.08 19.97±1.53 85.12±10.97
TTE2 2.9±0.41 34.62±9.29 20.12±5.69 87.87±13.94
p value 0.9871 0.8829 0.9448 0.5816
21mm
TEE 2.56±0.32 26.92±5.93 15.43±3.86 84.8±8.58
TTE2 2.64±0.39 28.33±8.25 16±5.02 83.20±12.37
p value 0.4577 0.5340 0.7063 0.5732
23 mm
TEE 2.47±0.30 24.93±5.61 13.85±3.18 87.77±9.85
TTE2 2.35±0.25 22.22±4.58 12.67±2.40 82.33±18.11
p value 0.3680 0.2918 0.4504 0.3660
25 mm
TEE 2.19±0.28 19.33±4.72 9.66±1.52 87.33±8.08
TTE2 2.19±0.17 19.33±2.89 10.00±0.87 79±4.58
p value 0.9900 0.9999 0.8218 0.2863
27 mm
TEE 1.80±0.24 13.3±3.69 7.3±1.86 87.8±4.14
TTE2 2.02±0.29 16.8±4.55 9.4±3.21 79.40±8.20
p value 0.3864 0.3711 0.3777 0.0839
53
Figure 11:Correlation between the intraoperative TEE and postoperative TTE (TTE2)
Doppler parameters of CHVP
Peak velocity (r = 0.5426), peak gradient (r = 0.5393) and mean gradient (0.5286) assessed by
TTE after 3 months of surgery (TTE2) showed a good and statistically significant direct
correlation with the intraoperative Doppler parameters measured by TEE.
[r – Pearson correlation co-efficient:positive value signifies direct correlation and values close to
1 indicates significant correlation.]
0
5
10
15
20
25
30
35
40
45
50
1
2
4
1 2 4 8 16 32 64
Foll
ow
up
aft
er 3
mon
ths
(TT
E2
) -
Pea
k a
nd
mea
n g
rad
ien
t
Foll
ow
up
aft
er 3
mon
ths
(TT
E2
) -
Pea
k v
eloci
ty
Intraoperative TEE
Peak Velocity (m/sec) Peak Gradient (mm Hg)
Mean gradient (mm Hg) Linear (Peak Velocity (m/sec))
Linear (Peak Gradient (mm Hg)) Linear (Mean gradient (mm Hg))
r = 0.5426
p = 0.0003
r = 0.5393
p = 0.0003
r = 0.5286
p = 0.0005
54
Table 11: Patient-prosthesis mismatch detection by intraoperative TEE
The IOA > 0.85 cm2/m
2 was regarded as absence of PPM and IOA < 0.85 cm
2/m
2 was regarded
as presence of PPM as per ASE guidelines. The required size of CHVP to provide IOA of > 0.85
cm2/m
2 was derived in the pre-CPB period from the results published by Namboodiri et
al14
which were used as reference values. We predicted that if the derived size of CHVP would be
implanted in aortic position, there would not be any PPM in the post-CPB period. TEE
examination was performed in the post-CPB period and IOA of the implanted CHVP was
measured. Also, the size of CHVP implanted was noted. We tested the sensitivity, specificity,
positive predictive value and negative predictive value of intraoperative TEE towards detecting
the presence of PPM (when the predicted size of CHVP was implanted, as well as when the
predicted size was not implanted). The results are mentioned in the Table 11.All the results were
statistically significant (P value < 0.0001).
Predicted-required
CHVP as per size & IOA
(n = 40)
Predicted CHVP
size not implanted
(n = 16)
[PPM present]
Predicted CHVP
size implanted
(n = 24)
[PPM absent]
Value (confidence interval)
IOA by TEE
< 0.85 cm2/m2
(n = 9)
9 (23%)
0
Sensitivity: 56.25 %
(29.88% to 80.25%)
Specificity: 100 % (85.75 %
to 100%)
Positive predictive value:
100% (66.37% to 100%)
Negative predictive value:
77.42% (58.90% to 90.41%)
IOA by TEE
≥ 0.85 cm2/m
2
(n = 31)
7 (17%)
24 (60%)
55
None of the patients in whom the predicted size of CHVP was implanted, developed PPM. All
the patients who developed PPM were those in whom the predicted CHVP size was not
implanted. Seven patients in whom the predicted size of CHVP was not implanted, had no PPM.
Figure 12:Correlation between the projected (IOA) and intraoperative TEE derived IOA
The projected indexed orifice area showed a good and statistically significant direct correlation
with the intraoperative IOA measured by transesophageal echocardiography (r = 0.4886).
(r – Pearson correlation co-efficient, positive value close to 1 indicatessignificant correlation,
whereas positive value signifies direct correlation.)(Abbreviations: - IOA – indexed orifice area,
TEE – transesophageal echocardiography)
0.5
0.7
0.9
1.1
1.3
1.5
1.7
0.5 0.7 0.9 1.1 1.3 1.5 1.7
Intr
ao
per
ati
ve
TE
E I
OA
(cm
2/m
2)
Projected IOA (cm2/m2)
r = 0.4886
p = 0.0014
56
Table 12:- Comparison of intraoperative TEE Doppler parameters of CHVP with the published
TTE data of St. Jude Medical Bileaflet mechanical valve prosthesis 18
[Abbreviations: - DVI- Doppler velocity index, SJM (BL) – St. Jude Medical Bileaflet, CHVP
– Chitra Heart Valve Prosthesis]
Valve
Size
Peak
velocity
(m/sec)
Peak
gradient
(mm Hg)
Mean
gradient
(mm Hg)
DVI
Effective
orifice
area
(cm2)
LVOT
Diameter
(cm)
19 mm
CHVP 2.91±0.13 34.10±3.08 19.97±1.53 0.38±0.08 1.35±0.21 1.97±0.10
SJM (BL) 3.0±0.6 37.10±16.06 17±7 0.37±0.07 0.99±0.20 1.85+0.07
p value 0.6726 0.2178 0.2501 0.7890 0.0029 0.0151
21mm
CHVP 2.56±0.32 26.92±5.93 15.43±3.86 0.42±0.06 1.61±0.19 2.22±0.22
SJM (BL) 2.7±0.3 30.07±6.35 14±5 0.40±0.06 1.25±0.21 2.00+0.04
p value 0.2349 0.1799 0.3995 0.3780 <0.0001 0.0019
23 mm
CHVP 2.47±0.30 24.93±5.61 13.85±3.18 0.40±0.08 2.04±0.14 2.41±0.22
SJM (BL) 2.8±0.5 31.88±11.86 16±6 0.37±0.06 1.28±0.31 2.10+0.12
p value 0.0513 0.0600 0.2543 0.3447 < 0.0001 0.0029
25 mm
CHVP 2.19±0.28 19.33±4.72 9.66±1.52 0.46±0.05 2.19±0.13 2.73±0.16
SJM (BL) 2.6±0.5 27.37±9.93 13±6 0.42±0.08 1.8±0.41 2.32+0.15
p value 0.1080 0.0790 0.0907 0.3279 0.1318 0.0608
27 mm
CHVP 1.80±0.24 13.3±3.69 7.3±1.86 0.46±0.14 2.44±0.04 2.88±0.25
SJM (BL) 2.2±0.5 21.73±9.13 11±5 0.46±0.10 2.43±0.63 2.58±0.20
p value 0.1264 0.0850 0.1442 0.9999 0.9706 0.0669
57
We observed no difference with respect to peak velocity, peak gradient, mean gradient and DVI
among CHVP and the St. Jude valve of same sizes. The LVOT diameter and EOA of CHVP
were significantly higher for 19, 21 and 23mm valves when compared to St. Jude valves of same
sizes. There was no difference with respect to LVOT diameter and EOA among CHVP and the
St. Jude valve of sizes 25 and 27 mm. The EOA measurement is significantly affected by the
LVOT diameter because any variations in the measurement are squared during calculation of
cross sectional area.
58
DISCUSSION
59
DISCUSSION
Chitra heart valve prosthesis (CHVP) is an indigenous, tilting-disc heart valve
developed by the Sree Chitra Tirunal Institute for Medical Sciences and Technology
(SCTIMST), India40
. It has gained a huge acceptance all over the nation because of its low cost,
high excellence and durability. After its first implantation in December 1990, a potential market
was established for the valve in India, neighboring countries, as well as South Africa. Till now,
CHVP has nearly 100,000 implantations to date. The clinical efficacy and the normal
postoperative transthoracic echocardiographic parameters of CHVP have been well studied and
reported in literature13, 41
. The postoperative CHVP Doppler parameters implanted at mitral and
aortic positions were comparable with those obtained with the different mechanical valves in
common practice14, 15
.
Intraoperative TEE has become an essential imaging modality during heart valve
surgeries42
. Studies have shown that post-CPB TEE has a major impact on the outcome of valve
replacement surgeries43, 44
. Current ASE/SCA guidelines have strongly endorsed the use of TEE
for the assessment of prosthetic heart valves to establish baseline reference values immediately
after valve replacement2. Therefore, it is necessary to define the intraoperative echocardiographic
characteristics and flow profile of different sizes of CHVP using 2D, color flow Doppler and
spectral Doppler examination.Although CHVP has been in use for more than 25 years and
postoperative follow up studies have reported excellent long term clinical outcomes, no reports
are available in the literature which describe the intraoperative TEE Doppler parameters of
CHVP at the aortic position.
60
Hence, we planned this study to establish a reference for the normal intraoperative
echocardiographic parameters of CHVP at aortic position using TEE in the post-CPB period. We
compared this data with the postoperative TTE Doppler parameters obtained 48 hours after
surgery when the inotropes were weaned off and later 3 months following the surgery. The
correlation of echocardiographic data between the intraoperative and postoperative follow-up
period was derived. The normal Doppler echocardiographic data of CHVP obtained in this study
was also compared with the published Doppler parameters of other prosthetic valves in common
practice. The sensitivity and specificity of intraoperative TEE to predict PPM was also evaluated.
We have obtained intraoperative TEE data in 40 patients implanted with five different sizes of
CHVP (19, 21, 23 25 and 27mm) at aortic position. Even though 17 and 29 mm size valves are
also available, they are uncommonly implanted and hence not included in our study.
Hemodynamic state during intraoperative and postoperative period
Measurement of Doppler velocities and gradients across the prosthetic valve in
the immediate post-CPB period are influenced by various confounding factors45
. During this
period, the loading conditions of the heart are altered by surgical site bleeding, infusion of intra-
venous fluids, return infusion of CPB reservoir blood,and transfusion of blood. Frequent changes
in the preloading conditions resulting from an inconsistent intravascular volume status may vary
the flow across the prosthetic valve and the measurement of flow dependent Doppler parameters.
Therefore, in order to perform an accurate Doppler evaluation of prosthetic valves, it is essential
to maintain a constant loading condition prior to Doppler examination. Increased contractility
induced by the inotropic supports in the immediate post-CPB period may increase the cardiac
output producing false high gradients across the prosthetic valves. Absence of atrial phase of LV
diastolic filling during ventricular pacing reduces the preload and stroke volume in the post-CPB
61
period. High cardiac output state may be produced by inotrope-induced tachycardia and
hemodilution from CPB prime, which elevates the peak velocity and pressure gradients.
In our study, we maintained constancy of preloading conditions by keeping the
central venous pressure (CVP) between 10 to 12 mm Hg before measuring the Doppler
parameters. Maintaining the hematocrit at around 30 % in all the patients during TEE
examination minimized the consequences of hemodilution on Doppler measurements. Since the
patients included in our study had good LV systolic function (LVEF = 58.47 ± 7.73 %),
inotropes were rarely needed in the post-CPB period.
Post-operative TTE evaluation was done twice; first on the 3rd
post-operative day
and the second after 3 months. By day 3, the inotropic support was weaned off and the patients
were hemodynamically stable. The prosthesis was also evaluated 3 months after the surgery
expecting maximum regression of the LV hypertrophy, improvement in the LV systolic function
and functional class, and resorption of paravalvular edema. The hemodynamic condition of all
the patients was stable during the postoperative follow up period.
The Doppler profiles archived during intraoperative period, 3rd
post-operative day
and 3 months after surgery were not significantly different despite the presence of high cardiac
output state and proactive hemodynamic factors such as inotropes, hemodilution, tachycardia and
cardiac pacing in the intraoperative period. It suggests that these factors have an insignificant
effect on the intraoperative Doppler characteristics, which may be treated as the reference values
for future Doppler studies conducted during the follow-up period.
62
2D and color Doppler evaluation of aortic CHVP
The two dimensional and color Doppler TEE features of CHVP were compliant
with the recommendations by ASE for prosthetic valve evaluation5. On 2D echo examination,
the sewing ring was found to be stable in all patients without any dehiscence or rocking motion.
The movement of the occluder disc was free making an angle of opening between 60 and 70
degrees. Color Doppler interrogation across the prosthetic valve revealed the major and minor
orifices occupying 70 % and 30 % of the internal geometric area respectively. Distinctive one to
two washing jets were observed in all the patients. No significant pathological transvalvular
regurgitation was noted in any of the patients. Trivial paravalvular leak at the suture sites noticed
in two patients immediately after CPB was weaned off, disappeared after administration of
protamine.
Spectral Doppler assessment of CHVP
The systematic assessment of prosthetic aortic valve has been described in the
ASE guidelines5. The Doppler parameters to be evaluated were contour of the velocity jet, peak
velocity, mean and peak gradient, DVI, AT, AT/ET ratio, EOA, IOA. When the peak velocity
exceeds 3 m/sec and the DVI remains below 0.3, then the prosthetic valve needs further
evaluation (Figure 2). The likely causes may be prosthetic valve stenosis or dysfunction, high
flow across the valve, patient prosthetic mismatch (PPM), improper Doppler insinuation of
LVOT, and sub-valvular narrowing. Tachycardia (heart rate >100/min) may also falsely raise the
pressure gradients. In our study only one patient with 19 mm valve had a peak velocity of more
than 3 m/sec (3.2m/sec).Further analysis of this patient, revealed DVI of 0.31, triangular early
peaking velocity jet, acceleration time of 76 msec and an indexed orifice area of 0.78 cm2/m
2. In
this patient, we diagnosed moderate PPM in a normally functioning prosthetic valve.
63
Doppler-derived velocity and gradients
Application of modified Bernoulli equation provides precise estimation of
pressure gradients across the normal prosthetic valves and at various degrees of valve stenosis in
the absence of sub-valvular obstruction46, 47
. Studies have demonstrated a very good correlation
between the Doppler gradients derived by Bernoulli equation and those measured by catheter
study in a recipient of a prosthetic valve. This correlation was demonstrated in the recipients of
various types of prosthetic heart valves48, 49
. However, the flow velocity and the pressure
gradients across the valve may differ among valves of different designs, sizes and at variable
flow conditions 50- 52
. In our study, we observed a significant inverse correlation of peak velocity
and pressure gradients with the increase in the valve size. There is evidence from numerous
studies that even though an inverse relation occurs between the valve size and pressure gradients,
the pressure gradients may display overlap among same sizes of different prosthetic valve
designs and also among the different sizes of the same prosthetic valve design53-55
. The high flow
conditions generate a major impact on pressure gradients produced across the valve. We also
found a significant overlap of the range of pressure gradients among different CHVP sizes which
we attribute to the high flow conditions rather than size of the valves. The Doppler gradient
observations of our study are consistent with the previous studies on aortic CHVP where the
gradients were measured after 3 months of surgery14
.
Contour of the velocity jet, acceleration time and AT/ET ratio
The contour of the velocity jet is a qualitative parameter that is used in
combination with quantitative indices like acceleration time and ratio of acceleration time to
ejection time (AT/ET ratio) to provide a valuable guide on prosthetic valve function. In a normal
functioning prosthetic valve, even during high flow rate, the shape of the jet is triangular with
64
early peaking and the AT is less than 100 ms. In the presence of any intrinsic valve stenosis or
obstruction, the contour becomes rounded, peaking during mid-ejection accompanied with
prolongation of AT and AT/ET ratio (AT > 100 ms and AT/ET > 0.4)56-58
. These parameters are
independent of flow and Doppler angulation. In our study the contour of the velocity jet was
triangular and early peaking in all the patients. The mean AT and AT/ET ratio were < 100 ms
and < 0.4 respectively and showed a poor correlation with the increase in the valve size. These
findings are acquiescent with ASE guidelines in differentiating a normal aortic prosthetic valve
from a stenotic one5.
Doppler velocity index
Another flow independent parameter recommended by the ASE to assess the
aortic prosthetic valve function is Doppler velocity index (DVI). It is a dimensionless index
calculated from the ratio of LVOT VTI to prosthetic valve VTI. DVI reflects the effect of flow
through the prosthetic valve on Doppler velocity18
. Therefore it may provide a guide to screen
valve dysfunction when the valve size or LVOT area is not known. In our study, DVI showed a
weak correlation with the valve sizes and the least value was 0.29 seen in two patients of 19 mm
size valve. A DVI < 0.25 suggests significant valve obstruction.DVI of a valve should be
referencedto normal values of a particular valve size59
. The DVI values of our study showed no
significant difference on comparison with the DVI of previous published studies on aortic
CHVP14
.
Effective orifice area by continuity equation
Effective orifice area (EOA), another flow independent parameter is derived from
the LVOT stroke volume using the continuity equation:
65
EOA = (LVOT area x LVOT VTI) / ProstheticAortic Valve VTI
Derived value of EOA depends on the size of the implanted valve. The EOA of a
valve should be referencedto normal values of a particular valve size. The EOA of CHVPs in our
study showed a significant direct correlation with the valve sizes. The average value for the 19
mm size valve was 1.35 cm2 and the lowest measured value was 0.96 cm
2. On comparison with
EOA values of published studyusing TTE14
, our EOA values were found to be significantly
higher. However, in our study, values of DVI were comparable with the values of DVI obtained
in the previous published TTE study14
.Studies have demonstrated that the major source of
variability in the calculation of EOA is the inconsistency in the measurement of LVOT
diameter60
. This inconsistency may be due to interference of prosthesis shadows, foreshortening
of LVOT, reverberation artifacts and the grade of septal hypertrophy below the annulus18
. The
subset of patients were different between our study and the previous published TTE study of
aortic CHVP14
, where the LVOT diameter could have differed between the two subset of
patients. This may be the reason for significant difference in EOA. In addition, the advances in
technology (X matrix vs conventional 2D phased array probes) and interrogation window (TTE
vs TEE) may also influence the LVOT measurements. It has been reported that TEE offers more
accuracy and reproducibility in the measurement of LVOT diameter than TTE, with which the
values may be underestimated61, 62
. Since there are no reported TEE studies on CHVP, we
compared our EOA values with those of previous TTE studies.
Indexed orifice area and patient prosthesis mismatch (PPM)
Patient-prosthesis mismatch is a common clinical problem in patients of aortic valve replacement
resulting in high transprosthetic gradient across a normally functioning valve63
. It is a long-term
problem having significant impact on improvement in functional capacity, hemodynamic status,
66
morbidity and mortality. According to literature, the best parameter used to describe PPM is
indexed orifice area (effective orifice area of the prosthetic valve / BSA of the patient) 20, 64
. The
severity of PPM is classified based on the IOA as65, 66
:no PPM – IOA ≥ 0.85 cm2/m
2, moderate
PPM – IOA 0.65-0.85 cm2/m
2 and severe PPM – IOA < 0.65 cm
2/m
2. Although, in our study the
mean IOA values of 19 mm and 21 mm CHVP are 0.87 cm2/m
2 and 0.94 cm
2/m
2 respectively, 4
patients in 19 mm and 5 patients in 21 mm valve group had moderate PPM according to the
above mentioned classification. However, among the 9 patients, only one patient in 19mm valve
group had peak velocity of > 3 m/sec while the others had values in higher normal range (Peak
velocities 2.8 - 3 m/sec). In our patients, moderate PPM (as assessed using IOA) detected by
intraoperative TEE was 23% which coincides well with the reported prevalence rate of previous
studies67, 68
.
Comparison of intraoperative TEE gradients with postoperative TTE gradients
Measurement of intraoperative TEE gradients is influenced by various
perioperative factors45
. We compared and correlated the TEE parameters with those of
postoperative TTE done after 48 hours (TTE1) and after 3 months of surgery (TTE2) in our
patients. The early postoperative (TTE1)gradients obtained after weaning offthe inotropes and
stabilization of hemodynamic state showed relatively lesser gradients (than TEE) except for 27
mm valves, although the differences were statistically insignificant. The late postoperative
(TTE2)gradients were found to be comparable with TEE gradients. We found a statistically
significant good positive correlation of peak velocity, peak gradient and mean gradient between
the intraoperative TEE and postoperative TTE values (TTE1 and TTE2). These findings did not
agree with those by Levy et al 26
where they assessed the TEE Doppler gradients immediately
after weaning the patient from CPB before protamine administration and compared them with
67
TTE values obtained at 2-4 months after surgery. In our study, we assessed both flow-dependent
and flow-independent parameters after the administration of protamine and optimization of
loading conditions and hematocrit. The fact that our assessment was done after protamine
administration and achieving hemodynamic stability, might have given a better correlation
between the intraoperative TEE values and postoperative TTE values in our study. Neither
assessment of flow-independent parameters in the intraoperative period, nor the re-evaluation of
Doppler parameters 48 hours after the surgery were the objectives of the study by Levy et al. In
our study, we measured flow-independent parameters AT, AT/ET, DVI and EOA which were
comparable with the published TTE studies of aortic CHVP. Flow-independent parameters
depict valve function better than the flow-dependent parameters like peak velocity and mean
gradient which may be influenced by the use of inotropes, tachycardia and high output states in
the post-operative period.
Comparison between CHVP and St. Jude Medical prosthesis
In the late 1970s, St. Jude medical prosthesis (SJM) was introduced into the
clinical practice. It is a bileaflet valve and its structure consists of a distinct hinge mechanism
where two crescent leaflets function in synchrony inside the annulus of the valve. It has an
excellent hemodynamic profile and its efficacy in aortic position has been demonstrated by
numerous clinical studies69, 70
. Since SJM implantation is most common in clinical practice, we
compared our intraoperative TEE Doppler parameters of aortic CHVP with the established
reference values of St. Jude medical (SJM) aortic prosthesis18
. The peak velocity, peak gradient,
mean gradient and DVI showed no significant difference between CHVP and SJM of same valve
sizes. On comparison between, CHVP and SJM of same valve sizes, the EOA showed a
significant difference for 19, 21 and 23 mm valve groups whereas it was comparable for 25 and
68
27 mm valves. The EOA measurement varies with the LVOT cross sectional area (CSA). Since
the calculation of DVI was independent of LVOT CSA, the DVI values among the CHVP and
St. Jude valves were not statistically different. Also, the subset of patients were different between
the two studies. Probably that could explain the observed difference in the EOA between CHVP
and SJM of same valve sizes.
Prediction of PPM by intraoperative TEE
Studies have shown that PPM can be avoided by implanting a valve that will
provide an adequate indexed EOA. The desired size and make of the prosthesis can be predicted
using the normal reference values from the published data65
. However, sometimes, the surgeon
may not be able to place the required valve due to anatomical constraints71, 72
. The prediction of
PPM by intraoperative TEE has not been studied previously. Projected indexed orifice area
calculated from the EOA of the valve to be implanted (taken from the published study14
) divided
by BSA, has reported to be the best intraoperative predictor of PPM by various studies37
. Our
reports showed that the prediction rate of PPM by intraoperative TEE was significant with
56.25% sensitivity and 100% specificity. The projected IOA had a good direct correlation with
the IOA measured by intraoperative TEE after valve implantation.
69
LIMITATIONS OF
THE STUDY
70
LIMITATIONS OF THE STUDY
Although the echocardiographic characteristics of CHVP comply with the
guidelines recommended by ASE, we acknowledge that there are certain limitations to our study.
The study subjects were selected from a single tertiary center. Probably a multicenter study
involving diverse ethnic population having different height, weight and BSA may be better in
generalizing the echocardiographic characteristics of the valve. Although we obtained
satisfactory results of performance of CHVP in 40 patients, a more conclusive evidence will be
obtained by conducting the study in large number of subjects. We did not analyzed the
interobserver and intraobserver variability in our patients. Even though the peak velocity and
mean gradients were within acceptable limits in the intraoperative period, we measured flow
independent parameters because variable preloading conditions, inotropic states, heart rate and
hemodilution may prevail in the post-CPB period that may confound the results. In the
postoperative period (after 48 hours and after 3 months), we limited the Doppler evaluation to
the measurement of velocity and gradients. Since there are no established reference values for
intraoperative TEE Doppler parameters of CHVP, we relied on the published TTE data to
compare our results. The projected IOA of our patients was also calculated from the published
TTE study.
71
CONCLUSION
72
CONCLUSION
CHVP of sizes ranging from 19 mm to 27 mm were implanted at aortic position
in the study participants and all the prosthesis were functioning well. On evaluation with 2D
echo, color Doppler and spectral Doppler, we found that TEE features of CHVP were compliant
with the criteria set by the ASE to describe a normal functioning aortic valve prosthesis. Aortic
CHVP can be adequately evaluated by intraoperative TEE.
1. The clinical parameters and echocardiographic examination suggests that the CHVP implanted
at aortic position provides satisfactory hemodynamic conditions after termination of CPB.
2. On 2D inspection, CHVP was found to have a stable valve seating and adequate occluder
motion. Color Doppler examination revealed the presence of two physiological jets (closing jet
and washing jet) in mid-esophageal views.
3. We evaluated both flow-dependent parameters (peak velocity, peak gradient and mean
gradient) and flow-independent parameters (AT, ET, AT/ET ratio, DVI and EOA) in all patients
in the intraoperative period. The Doppler parameters of CHVP were compliant with the ASE
recommendations for a normally functioning aortic valve prosthesis. Peak velocity was more
than 3 m/sec and mean gradient was more than 20 mm Hg in only one patient. Moderate PPM
(as assessed using IOA) was detected in nine (23%) patients, all of them implanted with either
size 19 mm or 21 mm prosthesis. All of them were receiving one or two inotropes in the post-
CPB period at the time of measurement of Doppler gradients. Although 2 patients in 19 mm
group had DVI of 0.29, AT and IOA in them were normal.
4. When the Doppler parameters of different sizes of CHVP were compared, the peak velocity,
peak gradient and mean gradient had strong inverse correlation with the size of the prosthesis
73
whereas the EOA and IOA had direct strong correlation with the valve size. The other
parameters such as AT, AT/ET and DVI did not appear to have any significant correlation with
the valve size.
5. The flow dependent Doppler parameters (peak velocity, peak gradient and mean gradient)
obtained by intraoperative TEE did not differ significantly from those obtained on 3rd
postoperative day and after 3 months of surgery. The TTE1 (48 hours after surgery) Doppler
parameters had a significant direct correlation and TTE2 (3 months after surgery) Doppler
parameters had a good direct correlation with the intraoperative TEE Doppler parameters
suggesting that the values of Doppler parameters obtained on intraoperative TEE predict the
postoperative values of Doppler parameters on TTE examination.
6. The published TTE data of St. Jude medical bileaflet prosthesis and intraoperative TEE
Doppler parameters of CHVP of same sized valves were comparable except for the EOA of
smaller valves (19 mm, 21mm and 23 mm).
7. We tested the specificity, positive predictive value, sensitivity and negative predictive value of
intraoperative TEE towards detecting the presence of PPM (when the predicted size of CHVP
was implanted, as well as when the predicted size was not implanted). Intraoperative TEE has
100% specificity in detecting absence of PPM. The positive predictive value of 100% suggests
that when the presence of PPM was predicted, it turned out to be true. However, the sensitivity
and negative predictive value were 56.25 % and 77.42% respectively suggesting that the role of
intraoperative TEE in detecting the presence of PPM where the predicted CHVP size was not
implanted is less. The projected IOA correlates well with IOA estimated by intraoperative TEE.
74
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85
ANNEXURES
86
ABBREVIATIONS
2D – two dimensional
ARE – Aortic root enlargement
ASE – American Societyof Echocardiography
AT – Acceleration time
AT/ET – Acceleration time/ejection time
AVR – Aortic valve replacement
BMI – Body mass index
BSA – Body surface area
CE- Continuity equation
CHVP- Chitra heart valve prosthesis
CPB- Cardio-pulmonary bypass
CWD - Continuous wave Doppler
DVI- Doppler velocity index
EOA- Effective orifice area
IOA- indexed orifice area
LA- Left atrium
LV- Left ventricle
LVEF – Left ventricular ejection fraction
LVID –Left ventricular internal diameter
LVOT – Left ventricular outflow tract
ME AV LAX - Mid-esophageal aortic valve long axis view
ME LAX – Mid-esophageal long axis view
NYHA – New York Heart Association
PPM- Patient prosthesis mismatch
PWD - Pulse wave Doppler
SCA – Society of Cardiovascular Anesthesiologists
SCTIMST- Sree Chitra Tirunal institute for medical sciences and technology
TEE- Trans-esophageal echocardiography
87
TG 2C – Transgastric two chamber view
TG 5C – Transgastric five chamber view
TG LAX – Transgastric long axis view
TTE – Transthoracic echocardiography
TTE1 – Transthoracic echocardiography- 48 hours after surgery
TTE2 – Transthoracic echocardiography- 3 months after surgery
TTK - T. T. Krishnamachari (founder of TTK Conglomerate)
VTI – Velocity time integral
USA – United states of America
88
Consent form
Title of the study:
“INTRAOPERATIVEHEMODYNAMIC PERFORMANCE AND ECHOCARDIOGRAPHIC
CHARACTERISTICS EVALUATION OF CHITRA HEART VALVE PROSTHESIS IN THE
AORTIC POSITION USING TRANSESOPHAGEAL ECHOCARDIOGRAPHY”
Study numbers: We request you to participate in the study wherein we are planning to evaluate
intraoperative echocardiographic characteristics of Chitra heart valve prosthesis in the aortic
position using Trans-esophageal echocardiography. We hope to include 40 people from this
hospital in this study.
What is Aortic valve?
Heart valves lie at the exit of each of your four heart chambers and maintain one-way blood flow
through your heart. The four heart valves make sure that blood always flows freely in a forward
direction and that there is no backward leakage. Aortic valve is one of the heart valves lying
between left ventricle and aorta.The aortic valve normally opens and closes to let the blood pass
away from the left side of the heart to other parts of the body.
What is Aortic valve replacement?
Aortic valve replacement is a open heart surgery to replace the aortic valve.If the aortic valve
does not open or close correctly due to disease, blood may not flow as it should. Aortic valve
disease can develop before birth (congenital) or can be acquired sometime during one's lifetime.
Hence diseased heart valve should be replaced with an artificial one.
What is Trans-esophageal echocardiography?
Trans-esophageal echocardiography or TEE is a test that uses sound waves to create high-quality
moving pictures of the heart and its blood vessels. This can pin point the problematic areas of the
heart and helpful in assessing function of heart valves before and after valve replacement
surgery. TEE involves a flexible tube (probe) with a transducer at its tip. Your doctor will guide
the probe down your throat and into your esophagus (the passage leading from your mouth to
your stomach). This will be done when you are under anesthesia and will not cause any
discomfort. This approach allows your doctor to get more detailed pictures of your heart because
the esophagus is directly behind the heart.
What is the role of Trans-esophageal echocardiography in valve replacement surgery?
Trans-esophageal echocardiography (TEE) is a useful monitoring tool during cardiac surgery.
American society of Anesthesiology and Society of cardiovascular Anesthesiologists have
strongly recommended the use of intraoperative TEE in adult patients undergoing valve
replacement to confirm and refine the preoperative diagnosis, to detect new or unsuspected
pathology, to adjust the anesthetic and surgical plan accordingly, and to assess the results of the
surgical intervention. This can pin point the problematic areas of the heart and helpful in
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assessing function of heart valves before and after valve replacement surgery. This is of great
help in assessing the heart function during the operation.
How is Trans-esophageal echocardiography performed?
This will be done when you are under anesthesia and will not cause any discomfort. Your doctor
will insert the lubricated probe into your mouth. He or she will then gently guide it down your
throat into your esophagus. Your esophagus lies directly behind your heart. During this process,
your doctor will take care to protect your teeth and mouth from injury.
What are the risks and side-effects?
We do not expect that our study will cause any injury to you because our study protocol is a part
of routine intraoperative TEE examination. You will be under the effect of anesthesia while the
test is being performed, thus you are unlikely to experience any discomfort.
Why are we doing this study?
The purpose of our research is to find out the hemodynamic characteristics of Chitra heart valve
placed in aorticposition with the help of Trans-esophageal echocardiography. This research will
involve collection of the data obtained during intraoperative period for the purpose of research
and publication regarding the study of hemodynamic profile of the Chitra heart valve prosthesis.
Can you withdraw from this study after it starts?
Your participation in this study is entirely voluntary and you are also free to decide to withdraw
permission to participate in this study. If you do so, this will not affect your usual treatment at
this hospital in any way.
What will happen if you develop any study related injury?
We do not expect any injury to happen to you but if you do develop any side effects or problems
due to the study, these will be treated at no cost to you. We are unable to provide any monetary
compensation, however.
Will you have to pay for the study? No.
Will your personal details be kept confidential?
Your personal details will be kept confidential. The result of this study will be published in a
medical journal but you will not be identified by name in any publication or presentation of
results.
If you have any further questions, please ask:
Dr. M.S.Saravana Babu, Senior Resident, Department of Anaesthesia (Ph No: 8589086898)
Dr.Rupa Sreedhar, Professor, Department of Anaesthesia.
Dr. Shrinivas Gadhinglajkar, Professor, Department of Anaesthesia.
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DECLARATION
I , ________________________________________________ ,
Participant’s name: Date of Birth / Age (in years) son / daughter of
___________________________________ (Please tick boxes) •declare that I have read the
above information provide to me regarding the study :
“Intraoperative hemodynamic performance and echocardiographic characteristics
evaluation of Chitra heart valve prosthesis in the aortic position using transesophageal
echocardiography”.
And have clarified any doubts that I had. [ ]
I also understand that my participation in this study is entirely voluntary and that
I am free to withdraw permission to continue to participate at any time without
affecting my usual treatment or my legal rights [ ]
I understand that the study staff and institutional ethics committee members will
not need my permission to look at my health records even if I withdraw from the
trial. I agree to this access [ ]
I understand that my identity will not be revealed in any information released to
third parties or published [ ]
I voluntarily agree to take part in this study [ ]
I received a copy of this signed consent form [ ]
Name:
Signature:
Name of witness:
Relation to participant:
(Person Obtaining Consent)
I attest that the requirements for informed consent for the medical research project
described in this form have been satisfied. I have discussed the research project with the
participant and explained to him or her in nontechnical terms all of the information
contained in this informed consent form, including any risks and adverse reactions that
may reasonably be expected to occur. I further certify that I encouraged the participant to
ask questions and that all questions asked were answered.
________________________________ ___________________
Dr. M.S.Saravana Babu,
Senior Resident, CVTA,SCTIMST.
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OBSERVATION CHART
Intraoperative hemodynamic performance and echocardiographic characteristics evaluation of
Chitra heart valve prosthesis in the aortic position using transesophageal echocardiography.
Name of the patient: Weight (kg):
Age: Height (cm):
Sex: Body surface area (kg/ cm2):
Hospital number:
Diagnosis and surgery: Date of surgery:
Preoperative features:
NYHA: Heart rate and rhythm:
Transthoracic echo report:
Preoperative medication:
Intraoperative echocardiographic observations
TEE findings before CPB:
Parameter Echo finding
LVEF (%)
LVIDD (mm)
LVIDS (mm)
LV posterior wall thickness systolic/ diastolic (mm)
Septal wall thickness systolic/ diastolic (mm)
Aortic valve examination:
AVA (cm2)
AV pressure gradient (peak systolic & mean) mmHg
LA size
Calcification of annulus
Grade of AR
Associated Mitral stenosis or regurgitation (grade)
Associated TR/PR
Any other
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CPB details:
CPB duration (minutes)
Aortic cross-clamp time (minutes)
Inotropes (mcg/ kg/ min)
1.
2.
Other drug infusions
1.
2.
Number of weaning attempts
Surgical details:
Size of Aortic valve prosthesis
Aortic root augmentation
Orientation anatomical/anti-anatomical
Hemodynamic and TEE findings after weaning from CPB
Hemodynamic
Heart rate (beats/ minute)
BP systolic /diastolic/mean during assessment
1.
2.
Rhythm
Cardiac Pacing, type
Filling pressures (mmHg)
Other
LVEF (%)
LVIDD (mm)
LVIDS (mm)
Grade of MR or MS
TEE Observations on CHVP examination
2D examination of CHVP
Motion of occluder disc (free/ restricted)
Angle of opening (degree)
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Motion of CHVP sewing ring (absent/ present)
Any characteristic appearance
Color Doppler examination of CHVP
Central leakage regurgitant jet (grade and number)
Regurgitant jet at contact between disc and stent (grade,
number)
Paravalvular regurgitant jet grade (before protamine)
Paravalvular regurgitant jet grade (After protamine)
Spectral Doppler examination of CHVP
Peak velocity (cm/s)
Peak systolic gradient (mmHg)
Mean gradient (mmHg)
Contour of the jet velocity
Acceleration time (ms)
Ejection time (ms)
AT/ET
VTI of LVOT (cm)
VTI of CHVP (cm)
DVI
Diameter of LVOT (cm)
LVOT area (cm2)
EOA of CHVP (cm2)
EOAi of CHVP (cm2/ m
2)
Stroke volume (ml/ min)
Heart rate (beats/ minute)
Blood pressure(S/D mm hg)
Cardiac output (lit/ min)
Cardiac Index (lit/ min/ m2)
PPM
Size of aortic root (mm)
Any other observations
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Postoperative Transthoracic echocardiographic observations
3rd
Post-operative Day (48 hours after surgery) TTE1 Date:
CHVP Size
LVEF (%)
LVIDD (mm)
LVIDS (mm)
LV posterior wall thickness systolic/ diastolic (mm)
Septal wall thickness systolic/ diastolic (mm)
Peak velocity (cm/s)
Peak systolic gradient (mmHg)
Mean gradient (mmHg)
Heart rate (beats/ minute)
MR/AR/TR/PR
Post-operative follow up (3 months after surgery) TTE2 Date:
CHVP Size
LVEF (%)
LVIDD (mm)
LVIDS (mm)
Peak velocity (cm/s)
Peak systolic gradient (mmHg)
Mean gradient (mmHg)
Heart rate (beats/ minute)
MR/AR/TR/PR
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TECHNICAL ADVISORY COMMITTEE APPROVAL
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INSTITUTIONAL ETHICS COMMITTEE APPROVAL
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PLAGIARISM ORIGINALITY REPORT
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MASTER CHART
PROJECTED EOA PROJECTED VALVE SIZE Intra-Op Intra -Op Mean
CHVP # IOA VALVE Prediction EOA Projected IOA
placed by PLACED post cpb TEE from previous study BSA mean IOA x BSA
TEE Doppler Y/N > 0.85 C/INC of placed CHVP
1 1.51 1.28 21 19 0.94 N INC 19 1.1 1.51 0.73
2 1.38 1.2 21 19 0.81 N C 19 1.1 1.38 0.8
3 1.52 1.3 21 19 0.78 N C 19 1.1 1.52 0.73
4 1.59 1.35 21 19 0.93 N INC 19 1.1 1.59 0.7
5 1.64 1.4 23 19 0.92 N INC 19 1.1 1.64 0.68
6 1.59 1.35 21 19 1 N INC 19 1.1 1.59 0.7
7 1.72 1.46 23 19 0.81 N C 19 1.1 1.72 0.64
8 1.58 1.34 21 19 0.79 N C 19 1.1 1.58 0.64
9 1.78 1.51 23 21 1.1 N INC 21 1.38 1.78 0.78
10 1.7 1.49 23 21 0.8 N C 21 1.38 1.7 0.81
11 1.61 1.37 21 21 1.1 Y C 21 1.38 1.61 0.86
12 1.69 1.44 21 21 0.99 Y C 21 1.38 1.69 0.82
13 1.82 1.55 25 21 0.73 N C 21 1.38 1.82 0.76
14 1.67 1.41 23 21 0.82 N C 21 1.38 1.67 0.83
15 1.78 1.51 23 21 0.94 N INC 21 1.38 1.78 0.76
16 1.73 1.47 23 21 0.84 N C 21 1.38 1.73 0.8
17 1.71 1.45 21 21 0.93 Y C 21 1.38 1.71 0.81
18 1.74 1.47 21 21 0.95 Y C 21 1.38 1.74 0.8
19 1.43 1.22 21 21 1.16 Y C 21 1.38 1.43 0.96
20 1.93 1.64 25 21 0.8 N C 21 1.38 1.93 0.72
21 1.69 1.44 21 21 1 Y C 21 1.38 1.69 0.82
22 1.48 1.26 21 21 1.08 Y C 21 1.38 1.48 0.93
23 1.82 1.55 23 21 0.92 N INC 21 1.38 1.82 0.76
24 2 1.7 23 23 1.3 Y C 23 1.76 2 0.88
25 1.7 1.44 23 23 1.12 Y C 23 1.76 1.7 1.03
26 1.89 1.61 23 23 1.04 y C 23 1.76 1.89 0.93
27 1.72 1.46 23 23 1.2 Y C 23 1.76 1.72 1.02
28 1.62 1.38 23 23 1.08 Y C 23 1.76 1.62 1.08
29 1.59 1.35 23 23 1.2 Y C 23 1.76 1.59 1.1
30 1.52 1.29 21 23 1.3 y C 23 1.76 1.52 1.15
31 1.79 1.52 23 23 1.2 Y C 23 1.76 1.79 0.98
32 1.69 1.44 23 23 1.2 Y C 23 1.76 1.69 1.04
33 1.57 1.33 23 25 1.3 y C 25 2.32 1.57 1.48
34 1.81 1.54 23 25 1.1 y C 25 2.32 1.81 1.28
35 1.87 1.59 25 25 1.27 Y C 25 2.32 1.87 1.24
36 1.62 1.38 23 27 1.3 Y C 27 2.33 1.62 1.43
37 1.91 1.62 25 27 1.2 Y C 27 2.33 1.91 1.22
38 1.61 1.37 23 27 1.49 Y C 27 2.33 1.61 1.45
39 1.65 1.4 23 27 1.5 Y C 27 2.33 1.65 1.41
40 1.73 1.47 23 27 1.4 Y C 27 2.33 1.73 1.35
PATIENTno CHVP Placed
RECOMMENDED
0.85 x BSA RECOMMENDEDBSA
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