DOPPLER EVALUATION OF BLOOD FLOW

THROUGH ANATOMICALLY NORMAL TRICUSPID

VALVE OF THE FETUS

• Tricuspid valve connects the right atrium and the right ventricle.

• It consists of 3 cusps; anterior, posterior and septal leaflets.

• The anterior, also called the infundibular or anterosuperior, leaflet is typically the largest.

• The posterior leaflet is also referred to as the inferior or marginal leaflet and the septal leaflet is also referred to as the medial leaflet.

• Terminating on the ventricular side of the tricuspid valve leaflets, the chordae tendinae are connected to three papillary muscles in the right ventricle. The anterior papillary muscle is usually the most prominent, with the moderator band terminating at its head.

ANATOMY AND DEVELOPEMENT

• The tricuspid valve is formed in

weeks 5-6 of embryonic

development.

• After the atrioventricular (AV)

endocardial cushions fuse, each

atrioventricular orifice is

surrounded by local proliferations

of mesenchymal tissue, from

which the AV valves form and are

attached to the ventricular wall

by muscular cords.

• Finally, muscular tissue in the

cords degenerates and is

replaced by dense connective

tissue.

1. Screening for aneuploidies

in the at 11-14 weeks.

2. Cases with intra-uterine

growth restriction.

3. During fetal

echocardiogram.

INDICATIONS FOR TRICUSPID VALVE

ASSESSMENT

NORMAL FLOW PATTERN IN THE TRICUSPID

VALVE

• It is viewed in the 4 chamber

view of the heart.

• This view is obtained by placing

the probe just above the

diaphragm.

• The heart is viewed at the level

of the crux , If imaging just below

this level, the coronary sinus is

seen, if imaging just above the

crux, the left ventricular outflow

tract comes into view.

• The most anterior chamber is the

right ventricle, connected by the

tricuspid valve to the right atrium.

• Unidirectional.

• Biphasic

1. E- Wave.

2. A-Wave.

• E wave corresponds to early diastole flow of blood by pressure gradient from right atrium to right ventricle.

• A wave corresponds to atrial contraction in late diastole to actively push blood from the atrium to the ventricle.

• As the fetus ages, the E wave

form increases in height,

representing an increase in

speed as blood enters the

ventricular chambers during the

early filling phase of diastole.

• The A wave form does not

increase in speed as the fetus

ages. This suggests that the

speed of blood resulting from

atrial contraction remains

unchanged, irrespective of the

age of the fetus.

CHANGES IN E AND A WAVES THROUGHOUT

GESTATION

TEMPORAL RELATIONSHIP OF FLOW IN

TRICUSPID VALVE AND DUCTUS VENOSUS

ASSESSMENT OF ANEUPLOIDY

DURING FIRST TRIMESTER SCAN

• The gestational period must

be 11 to 13+6 weeks

• A four-chamber view of the

fetal heart should be

obtained

• A pulsed-wave Doppler

sample volume of 2.0 to 3.0

mm should be positioned

across the tricuspid valve

PROTOCOL FOR THE ASSESSMENT OF FETAL

TRICUSPID FLOW

• It should be kept in

mind that not all of the

leaflets of the TCV are

necessarily

incompetent. Therefore,

at least three Doppler

evaluations should be

obtained.

POINTS TO REMEMBER

• Tricuspid regurgitation

is diagnosed if it is

found during at least

half of the systole and

with a velocity of over

60 cm/s, since aortic or

pulmonary arterial

blood flow at this

gestation can produce a

maximum velocity of 50

cm/s.

A] Doppler flow profile in the

tricuspid valve with no

regurgitation during systole

B]Regurgitation during

approximately half of systole and

with a velocity more than 60 cm/s

C] The short reverse generated

by closure of the valve cusp

D] Jet produced by aortic or

pulmonary arterial blood flow,

which at this gestation can

produce a maximum velocity of

50 cm/s

11-14 week scan:

• 55% of cases of trisomy 21

• 30% of cases of trisomy 18

• 30% in cases of trisomy 13.

• 38% in cases of monosmy X

Other ultrasonographic markers

must also be evaluated for complete

risk assessment.

SIGNIFICANCE OF TRICUSPID VALVE REGURGE

AT 11-14 WEEKS

REGURGITATION IN ANATOMICALLY NORMAL

HEART WITH NO OTHER MARKERS OF

ANEUPOLIDY

1. increased preload [e.g. congestive

heart failure]

2. Increased afterload [e.g. pre-

eclampsia or indomethacin exposure]

3. Myocardial impairment

4. Dysrhythmia.

In the majority of cases (92%) the

possible cause may be established. In

other cases (8%) there may be "idiopathic"

tricuspid valve regurgitation.

CAUSES

ASSESSMENT OF TRICUSPID VALVE IN CASES

OF INTRAUTERINE GROWTH RESTRICTION

• E/A ratio is higher than normal fetuses of similar gestational age.

• This is due to preload impairment [not enough blood supply reaches the fetal circulation] without impairment in fetal myocardial diastolic function.

•

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