rose protocol transcatheter pressure...
TRANSCRIPT
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Rose Protocol: Transcatheter pressure monitoring to assure hemodynamic effect
and to quantify a hemodynamic endpoint for embolization
Steven C. Rose ∙ Rachel Schrader
1 OVERVIEW
This protocol provides set‐up instructions for
the transcatheter pressure monitoring
configuration shown in Figure 1. Additionally,
this protocol explains how pressure
measurements are taken and interpreted.
With this transcatheter pressure monitoring
method, one can accurately compare systemic
blood pressure (BP) with the pressure at the tip
of the microcatheter with balloon occlusion to
determine:
1) if the microcatheter is adequately
occlusive
2) if blood flow will be directed into the
downstream vascular compartment from
adjacent vascular compartments to
provide antegrade protection from
nontarget embolization and likely
increase the proportion of embolic
delivery into the tumor
3) a potential hemodynamic endpoint for
embolization
This method uses two transducers to allow for
simultaneous comparison of the systemic
blood pressure with the pressure at the tip of
the microcatheter with balloon occlusion.
Given the patient’s BP will change moment to
moment, simultaneous comparison is
important for accuracy and to mitigate
measurement artifacts.
Keywords Chemoembolization ∙
Radioembolization ∙ Embolization Endpoint ∙
Embolization ∙ Pressure‐directed ∙ Balloon
occlusion
S. C. Rose () ∙ R. Schrader
Department of Radiology 8756, UCSD Medical Center,
University of California, San Diego Health Sciences, 200
West Arbor Drive, San Diego, CA 92103‐8756, USA
e‐mail: [email protected]
©Embolx, Inc. 2019. MK‐0327‐03 Rev. A
Figure 1: Transcatheter pressure monitoring configuration
7 11
11
10
1. Microcatheter balloon
2. Microcatheter
3. Microcatheter hub
4. Base Catheter
5. Introducer sheath
6. Rotating Hemostasis Valve
7. Saline lines packaged with transducer
8. 20 ml syringe, introducer sheath flush
9. 20 ml syringe, microcatheter flush
10. 20 ml syringe, transducer flush
11. 3‐way stopcock, packaged with transducer
12. 3‐way stopcock, stand‐alone
13. Embolic agent injection line
Tran
sducer 2
MICROCATH
Tran
sducer 1
SHEA
TH
8
7
9
11
1
2
5
6
11
3
11
10
4
13
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2 SET‐UP
2.1 ITEMS NEEDED FOR SET‐UP QUANTY ITEM
1 Embolx Sniper® Balloon Occlusion Microcatheter
2 Edwards LifeSciences™ TruWave™ Disposable Pressure Transducer (PX272)
2 Reusable Edwards LifeSciences Transducer to bedside monitor cable (PX1800). Contact Edwards Lifesciences for the specific cable version to connect a TruWave transducer to your bedside monitor model
1 Reusable IV pole mount for Edwards LifeSciences TruWave Disposable Pressure Transducer (TCLIP05)
1 3‐way stopcock
4 20 ml syringe filled with saline
1 Laser level
2.2 SET‐UP PROCEDURE 1. Set‐up two (2) Edwards LifeSciences TruWave Disposable Pressure Transducers (Figure 2):
a. Open on the sterile field two (2) TruWave Pressure Transducers.
b. Disconnect tubing lines from transducers. Each transducer is packaged with two (2) lines connected: one line
has a vent spike; the other line has a 3‐way stopcock.
c. Discard two (2) spike vent lines.
d. Save two (2) transducers for later use.
e. Save two (2) saline lines with 3‐way stopcocks for later use.
Figure 2: Pressure Transducer Set‐up
Tran
sducer 1
Save
Tran
sducer 2
Transducers from packages
Discard
Lines connected Lines disconnected
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2. Set‐up two (2) 20 ml syringes (Figure 3):
a. Open on the sterile field two (2) 20 ml syringes.
b. Fill both syringes with saline, label one SHEATH and the other MICROCATH.
c. Attach the first 20 ml syringe filled with saline to a 3‐way stopcock on a saline line from step 1e.
d. Attach the second 20 ml syringe filled with saline to the remaining 3‐way stopcock on the other saline line
from step 1e.
Figure 3: 20 ml flush syringe set‐up
3. Set‐up two (2) transducers (Figure 4):
a. Clip the transducer mount firmly onto IV pole.
IMPORTANT! Use an IV pole originating on the procedure
table because when the patient table moves up or down, it
is important that the transducer location relative to the
patient is maintained.
b. Label one transducer “SHEATH” and other
“MICROCATH”
c. Fill two (2) 20 ml syringes with saline.
d. Attach the first 20 ml syringe filled with saline to a
transducer from step 1d.
e. Attach the second 20 ml syringe filled with saline to the
remaining transducer from step 1d.
f. Mount two (2) transducers with 20 ml syringe filled
with saline to transducer holder on IV pole with the
transducer connection cables hanging down.
g. Connect two (2) sterile saline lines from step 2 to both
transducers.
h. Discard the white caps on both transducer 3‐way
stopcocks.
i. Connect both transducer connection cables to two bedside monitor cables. Connect the bedside monitor
cables to the appropriate bedside monitor ports.
Figure 4: Transducer set‐up
SHEA
TH
MICR
OCAT
H
SHEA
TH
MICR
OCAT
H
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4. Position and level the two transducers to the patient’s mid‐axillary line and 4th intercostal space (Figure 5):
a. Move IV pole forward or backward on the patient’s table until the transducers are positioned at the patient’s
4th intercostal space.
b. Using a laser level, slide the transducers up or down on the IV pole into position so that they are level to the
patient's mid‐axillary line while maintaining position at the patient’s 4th intercostal space.
IMPORTANT! The laser level should be aligned with the top of the 3‐way stopcocks on the transducers.
IMPORTANT! The transducers must be exactly positioned to ensure accurate pressure readings.
Figure 5: Exact positioning of the two transducers*
5. Figure 6):
a. Turn 3‐way
stopcocks on both transducers open to air
(pointed up as shown in Figure 4)
b. Label the transducers on the monitor:
“MICROCATH” and “SHEATH”.
c. ZERO both transducers by pressing the ZERO
on the monitor.
d. Set the scale on the monitor for both the
MICROCATH and the SHEATH pressure
measurements to a 150 scale or slightly
greater than systolic blood pressure as
measured on the noninvasive system.
* Edwards Lifesciences TruWave Transducer Setup. https://www.edwards.com/devices/pressure‐monitoring/transducer
Figure 6: Bedside monitor set‐up
Set‐up bedside monitor (
Raise or lower transducers until level with mid-axillary line
Move the IV pole until transducers are positioned at the patient’s 4th intercostal space
Noninvasive BP measurement
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6. Connect the stand‐alone 3‐way stopcock, V5, to
the end of the microcatheter saline line as
shown in Figure 7.
7. Flush the saline lines from the transducers to a
point just beyond valves V3 and V5 creating an
air and bubble free continuous fluid column
(Figure 7):
a. With valves V3 and V4 in the "syringe
off" position and V5 in the “embolic
agent inject off” position, pull the snap
tab on the transducer while
simultaneously filling the saline lines
using syringes S1 and S2. Tap the lines
while holding them upright to work out
any air bubbles.
b. Move the 3‐way stopcock to the
"transducer off" position on valves V3
and V4 per motion marked A. This action
keeps air from entering the lines
towards the transducers.
c. Use syringes S3 and S4 to flush residual
air out of the open end of the saline
lines. Tap the lines to work out air
bubbles.
d. Move the 3‐way stopcock to the "saline line off" position on valve V5 per in motion marked B. This action
keeps air from entering the microcatheter saline line.
IMPORANT! Check the entire configuration for air bubbles and line kinks which are the most‐common problem
when measuring pressure and can result in inaccurate readings. Pressure measurement requires a continuous
fluid column.
8. Connect the saline lines to both the introducer sheath and the microcatheter (Figure 8).
a. Connect sheath line to the introducer sheath per configuration shown in Figure 8.
b. Connect microcatheter line to the microcatheter 3‐way stopcock per configuration shown in Figure 8.
Figure 7: Initial saline line flush to remove air and bubbles
MICROCATH
SH
EATH
MICR
OCAT
H SH
EATH
Snap Tab Flush
Tap lines while holding upright to work out air bubbles
Tap lines while holding upright to work out air bubbles
Air and bubbles are removed and replaced with saline
S3
S4 S1 S2
V1 V2
V3
V4 V5
Embolic agent inject
Microcatheter connect
Sheath connect
A
A
B
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3 PRESSURE MEASUREMENT AND EMBOLIC AGENT DELIVERY
1. Measure and record pressures from both the introducer sheath and the microcatheter (Figure 8):
a. Flush the sheath and microcatheter lines using syringes S3 and S4.
b. Move the 3‐way stopcock to the "syringe off" position on valves V3 and V4 per motion marked A.
c. Record sheath pressure. Record microcatheter pressure. For each pressure measurement of the sheath and
microcatheter lines, record the systolic, diastolic and mean pressures from the bedside monitor. Once embolic
agent delivery commences, wait until BP pressure readings stabilize before measuring pressures.
2. Inject Embolic agent via the microcatheter with occlusion balloon inflated (Figure 9):
a. Move the 3‐way stopcock to the "transducer off" position on valves V3 and V4.
b. Move the 3‐way stopcock to the "saline line off" position on valve V5 for embolic agent injection.
Figure 8: Pressure measurement configuration Figure 9: Embolic agent injection configuration
A
A
S3
S4
V4 V5
MICROCATH
SHEA
TH
V3
SHEA
TH
MICR
OCAT
H
S3
S4
V4 V5
MICROCATH
SHEA
TH
V3
SHEA
TH
MICR
OCAT
H
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4 PRESSURE MEASUREMENT INTERPRETATION
Studies to date on transcatheter pressure monitoring to assure hemodynamic effect and to quantify a hemodynamic
endpoint for embolization have been focused on the liver. Therefore, the following pressure measurement interpretation
guidance is based on liver experience only. While this protocol could be utilized in organs outside the scope of the liver
(e.g., kidney, prostate, pancreas, uterus), further study is to verify the hemodynamic effects of balloon occlusion in extra‐
hepatic organs, each with its own unique angioarchitecture.
As noted in the protocol, transducers are utilized to measure the systolic, diastolic, and mean systemic arterial blood
pressure (referred to as SHEATH), and the systolic, diastolic, and mean downstream vascular compartment arterial blood
pressure (referred to as MICROCATH). The systemic arterial blood pressure is measured directly through the side arm of
the femoral artery sheath. The sheath should have an inner diameter that is at least one French larger than the outer
diameter of the coaxial base catheter. Flushing the system vigorously with saline prior to each reading will help ensure
fidelity of the measurements.
The blood pressure within the vascular compartment that is downstream from the microcatheter is measured directly
through the lumen of the balloon mounted microcatheter. When the balloon is deflated, the downstream vascular
compartmental blood pressure should closely approximate the systemic arterial blood pressure unless the microcatheter
occupies a large portion of the arterial cross‐sectional area or unrecognized upstream arteriospasm has occurred. When
the balloon has been inflated to the point of arterial occlusion, the blood pressure in the downstream vascular
compartment should be reduced by 20‐50 mmHg relative to the systemic arterial blood pressure (1,2).
The systemic compartmentalized arterial pressure differential (SCAPD) = mean systemic arterial blood pressure (mmHg)
minus the mean downstream vascular compartment arterial blood pressure (mmHg). When calculating the SCAPD, using
the mean systemic and downstream blood pressures appears to be the most reliable pressure measurement. The systolic
blood pressure has excessive statistical noise (variability), and diastolic blood pressure downstream may actually be
higher than the systemic diastolic blood pressure (even before embolization) due to damping of the arterial wave form.
If the SCAPD is less than 20 mmHg, most likely the balloon is not occlusive. Additional inflation is indicated until an
appropriate SCAPD has been achieved. Once a suitable SCAPD has been attained (typically in the order of 40 mmHg),
then blood flow in hepaticoenteric arteries can be confidently assumed to flow hepatopetally, thus providing antegrade
protection from nontarget embolization in addition to the designed retrograde protection.
As a result of the 20‐50 mmHg SCAPD, blood flow enters the downstream vascular compartment not only through
hepaticoenteric arteries, but also through hepatic artery‐to‐hepatic artery connections between neighboring hepatic
segments. This results in reversal of downstream compartmental hepatic arterial blood flow due to collateral
reconstitution. Essentially embolic agent is flushed out of the nontumorous hepatic tissues. Presumably the tumor is a
separate vascular compartment, thus continues to fill with embolic agent. The net result, as supported by a number of
reported investigations (2,3,4) is increased delivery of agent to the tumor and reduced delivery to nontumorous liver. Of
note, if tumors receive competing arterial inflow from outside the downstream vascular compartment (i.e., “Watershed”
tumors), then these results may be less predictable (5).
Use of an occlusion balloon during embolization confounds the visual fluoroscopic clues used to determine the end point
of embolization. Specifically, the occlusion balloon dramatically reduces the forward blood flow velocity. In addition, by
design, the occlusion balloon serves as a back stop to reversal of blood flow. As embolization progresses, particles
occlude portions of the vascular compartment compartmental microvasculature, thus raising the downstream resistance
to blood flow. This increased downstream resistance results in progressive reduction in the SCAPD (6,7). The algorithm
adopted by the UCSD team involves repeated intraprocedural measurement of SCAPD after each delivery of
approximately 10% of the intended chemoembolization or Y90 radioembolization resin microsphere dose. Of note, Y90
glass microsphere doses cannot be partitioned. When relatively large volumes of liver are at risk (e.g., lobar delivery),
data seems to support safety using a 70% relative reduction in SCAPD as an embolization end point (7). In cases with
relatively small volumes of liver at risk (e.g., segmental or subsegmental delivery), then intentional over embolization may
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be an effective means for increasing embolic penetration into tumor and dealing with “watershed” tumors. Detailed
review of hemodynamic principals and preliminary clinical evidence has been presented [8].
As an example, Figure 10 shows the bedside monitor display at the first pressure measurement when the microcatheter’s
balloon was initially inflated, balloon occlusion was achieved (e.g. 38 mmHg pressure difference), and embolic agent (drug
eluting embolic with doxorubicin) injection has not yet commenced. Figure 11 shows the first and sixth pressure
measurement recordings (see section 6 for the measurement spreadsheet) with calculated mean pressures, pressure
difference (SCAPD) and percentage reduction of the SCAPD after delivery of approximately 60% of the intended dose of
embolic dose.
5 REFERENCES
1. Rose SC, Kikolski SG, Chomas JE. Downstream hepatic arterial blood pressure changes caused by deployment of the
surefire antireflux expandable tip. Cardiovasc Intervent Radiol 2013;36:1262‐9.
2. Rose SC, Halstead GD, Narsinh KH. Pressure‐Directed Embolization of Hepatic Arteries in a Porcine Model Using a
Temporary Occlusion Balloon Microcatheter: Proof of Concept. Cardiovasc Intervent Radiol 2017.
3. Irie T, Kuramochi M, Takahashi N. Dense accumulation of lipiodol emulsion in hepatocellular carcinoma nodule during
selective balloon‐occluded transarterial chemoembolization: measurement of balloon‐occluded arterial stump
pressure. Cardiovasc Intervent Radiol 2013;36:706‐13.
4. Pasciak AS, McElmurray JH, Bourgeois AC, Heidel RE, Bradley YC. The impact of an antireflux catheter on target volume
particulate distribution in liver‐directed embolotherapy: a pilot study. J Vasc Interv Radiol 2015;26:660‐9
5. Kothary N, Takehana C, Mueller K, et al. Watershed Hepatocellular Carcinomas: The Risk of Incomplete Response
following Transhepatic Arterial Chemoembolization. J Vasc Interv Radiol 2015; 26: 1122‐1129.
6. Rose SC, Lim GM, Arellano RS, Easter DB, Roberts AC. Temporary splenic artery balloon occlusion for protection of
nonsplenic vascular beds during splenic embolization. AJR 1998;170:1186‐8.
7. Rose SC, Kikolski SG, Morshedi MM, Narsinh KH. Feasibility of Intraprocedural Transluminal Hepatic and Femoral
Artery Blood Pressure Measurements as an Alternative Embolization Safety Endpoint When Antireflux Devices Are
Used During Lobar Chemoembolization. AJR 2015;205:196‐202.
8. Rose SC, Narsinh KH, Isaacson AJ, Fischman AM, Golzarian J. The Beauty and Bane of Pressure‐Directed
Embolotherapy: Hemodynamic Principles and Preliminary Clinical Evidence. AJR 2019 Mar;212(3):686‐695.
Figure 10: Bedside monitor display at baseline measurement Figure 11: Measurement recording example
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6 APPENDIX: PRESSURE MEASUREMENT RECORDING SPREADSHEET