Echo Evaluation of PS and PR

Pulmonary valve disease is commonly encountered in congenital and adult cardiology practice. Echocardiography remains the primary tool for diagnosis, severity assessment, and follow-up of Pulmonary Stenosis (PS) and Pulmonary Regurgitation (PR). A systematic echocardiographic approach helps determine valve morphology, hemodynamic severity, and the impact on right ventricular function.

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INTRODUCTION

Pulmonary valve pathology may occur as isolated congenital disease, after surgical repair of congenital heart defects, or secondary to pulmonary hypertension and endocarditis. Echocardiography provides comprehensive evaluation through:

• Valve morphology

• Doppler hemodynamics

• Right ventricular size and function

• Associated congenital abnormalities

Both PS and PR primarily affect the right heart, making careful right-sided assessment essential.

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ECHOCARDIOGRAPHIC VIEWS FOR PULMONARY VALVE

The pulmonary valve can be visualized in several standard echocardiographic views.

Parasternal Short Axis (PSAX) at the aortic valve level

Best view for pulmonary valve morphology.

Parasternal Right Ventricular Outflow Tract (RVOT) view

Useful for Doppler interrogation.

Subcostal RVOT view

Helpful when parasternal windows are suboptimal.

Suprasternal or modified views

Used in congenital cases or difficult imaging.

Color Doppler and continuous wave Doppler are essential for evaluating gradients and regurgitation severity.

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ECHO EVALUATION OF PULMONARY STENOSIS

Pulmonary stenosis is most commonly congenital and occurs due to commissural fusion of the pulmonary valve.

Valve Morphology

Typical findings include:

• Thickened pulmonary valve leaflets

• Doming of valve in systole

• Reduced leaflet mobility

• Post-stenotic dilation of the pulmonary artery

These findings are best appreciated in the PSAX view.

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DOPPLER ASSESSMENT OF PS

Continuous wave Doppler across the pulmonary valve is used to measure the peak velocity and pressure gradient.

Peak velocity is converted to pressure gradient using the modified Bernoulli equation:

Gradient = 4V²

Severity of Pulmonary Stenosis

Mild PS

Peak velocity < 3 m/s

Peak gradient < 36 mmHg

Moderate PS

Peak velocity 3–4 m/s

Peak gradient 36–64 mmHg

Severe PS

Peak velocity > 4 m/s

Peak gradient > 64 mmHg

Doppler beam alignment should be optimized using multiple windows including parasternal, subcostal, and suprasternal views.

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ADDITIONAL FINDINGS IN PS

Right ventricular changes may include:

• Right ventricular hypertrophy

• Right atrial enlargement

• Septal flattening in severe obstruction

• Dilated pulmonary artery due to post-stenotic flow

Assessment of RV function is important for long-term management.

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ECHOCARDIOGRAPHIC EVALUATION OF PULMONARY REGURGITATION

Pulmonary regurgitation is frequently seen after repair of congenital heart disease such as Tetralogy of Fallot, but it may also occur with pulmonary hypertension, infective endocarditis, or carcinoid disease.

Echocardiographic evaluation focuses on:

• Regurgitation severity

• RV dilation

• RV function

• Pulmonary pressures

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COLOR DOPPLER FEATURES OF PR

Color Doppler in the PSAX or RVOT view demonstrates a diastolic jet from the pulmonary artery into the right ventricle.

Features suggesting more severe PR include:

• Large central jet

• Jet width occupying >50% of RVOT

• Dense continuous wave Doppler signal

• Early diastolic deceleration of the jet

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DOPPLER PARAMETERS OF PR SEVERITY

Several Doppler findings help quantify PR severity.

Pressure Half Time (PHT)

Short PHT suggests severe regurgitation due to rapid equalization of pulmonary artery and RV pressures.

PHT < 100 ms

Suggests severe PR

Diastolic flow reversal in pulmonary artery branches

Supports severe PR

Dense CW Doppler signal

Suggests significant regurgitation.

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RIGHT VENTRICULAR ASSESSMENT IN PR

Chronic pulmonary regurgitation leads to right ventricular volume overload.

Important measurements include:

RV basal diameter

RV mid diameter

RV end diastolic area

TAPSE

RV fractional area change

Progressive RV dilation is a key marker guiding intervention in congenital heart disease patients.

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SPECIAL CONSIDERATIONS

After Tetralogy of Fallot repair, PR is common and may lead to progressive RV dilation. Serial echocardiography is essential to monitor RV size and determine timing of pulmonary valve replacement.

In pulmonary hypertension, PR velocity can also be used to estimate pulmonary artery diastolic pressure.

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KEY POINTS

• Echocardiography is the primary modality for evaluating pulmonary valve disease.

• Doppler assessment determines the severity of pulmonary stenosis.

• Color and CW Doppler help quantify pulmonary regurgitation.

• Right ventricular size and function must always be assessed.

• Serial echo follow-up is essential in congenital heart disease patients.

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