What is a normal pulmonary regurgitation end-diastolic velocity?

Normal Pulmonary Regurgitation End-Diastolic Velocity

The normal pulmonary regurgitation end-diastolic velocity is less than 20 cm/s (0.2 m/s). Values exceeding this threshold suggest hemodynamically significant pulmonary regurgitation 1.

Understanding Pulmonary Regurgitation

• Pulmonary regurgitation (PR) is the backward flow of blood from the pulmonary artery into the right ventricle during diastole 2
• Mild PR is common, occurring in 40-78% of patients with normal pulmonary valves, and is often considered a normal variant on echocardiography 1, 2
• Severe PR is uncommon and usually observed in patients with anatomic abnormalities of the valve or after valvulotomy 1

Echocardiographic Assessment of PR

Doppler Evaluation

• Detection of PR relies almost exclusively on color flow imaging, diagnosed by documenting a diastolic jet in the right ventricular outflow tract directed toward the RV 1
• Continuous wave Doppler provides important information about PR severity through the end-diastolic velocity measurement 1, 3
• End-diastolic velocity >20 cm/s is indicative of severe pulmonary regurgitation 1

Pressure Half-Time Assessment

• Pressure half-time (PHT) is another important parameter in assessing PR severity 3
• PHT <100 milliseconds indicates hemodynamically significant regurgitation 3
• In patients with repaired Tetralogy of Fallot, a pulmonary regurgitant fraction ≥20% is associated with significant increases in right ventricular end-diastolic volumes 3, 4

Clinical Significance

• Mild PR is generally well-tolerated and does not require specific treatment 2
• Isolated mild PR rarely causes right ventricular enlargement or dysfunction 2
• Severe PR can lead to right ventricular dilatation and diminished RV systolic performance, potentially resulting in exercise intolerance and heart failure 1
• In patients with repaired Tetralogy of Fallot, significant PR can be associated with ventricular arrhythmias and late sudden death 1

Monitoring and Follow-up

• Patients with mild PR without symptoms or structural heart disease typically need only periodic echocardiographic follow-up every 3-5 years 2
• More frequent monitoring may be warranted if there are associated valve abnormalities 2
• Cardiac magnetic resonance (CMR) is useful for evaluating pulmonary regurgitant fraction, RV end-diastolic and end-systolic volumes, and RV ejection fraction in cases of significant PR 1, 4

Pitfalls in Assessment

• The evaluation of pulmonary valve anatomy is more difficult than for other valves due to limited acoustic access 1
• Transesophageal echocardiography (TEE) has limited utility in PR assessment since the pulmonary valve is difficult to image (far from the probe) 1
• In patients with minimal PR, the maximum velocity typically does not exceed 1.5 m/s, with the highest diastolic transpulmonary pressure gradient estimated at no more than 9 mm Hg 5
• Doppler-measured pulmonary regurgitation index (PRi) correlates closely with CMR regurgitant fraction and can help identify significant PR 4

Remember that while end-diastolic velocity is an important parameter, a comprehensive assessment should include multiple echocardiographic parameters to accurately determine PR severity 1, 4.