Pulmonary (pulmonic) regurgitation (PR) is incomplete closure of the pulmonary valve causing backflow of blood from the pulmonary artery into the right ventricle during diastole. The most common cause is pulmonary hypertension. PR is usually asymptomatic. Signs include a decrescendo diastolic murmur. Diagnosis is by echocardiography. Usually, no specific treatment is necessary except for management of pulmonary hypertension.
(See also Overview of Cardiac Valvular Disorders.)
In adults, the most common cause by far of pulmonary regurgitation, also called pulmonic regurgitation or pulmonary insufficiency, is:
Secondary pulmonary hypertension
Less common causes are:
Idiopathic pulmonary artery dilation
Surgical repair of tetralogy of Fallot or other congenital heart disease involving the pulmonary valve
Rare causes are:
Following intervention for valvular pulmonary stenosis (early or late)
Congenital heart disease such as absent pulmonary valve syndrome and severe Ebstein anomaly
Severe pulmonary regurgitation is rare and most often results from an isolated congenital defect involving dilation of the pulmonary artery and pulmonary valve annulus.
PR may contribute to development of right ventricular (RV) dilatation and eventually RV dysfunction–induced heart failure (HF), but in most cases, pulmonary hypertension contributes to this complication much more significantly. Rarely, acute RV dysfunction–induced HF develops when endocarditis causes acute PR.
Symptoms and Signs of Pulmonary Regurgitation
Pulmonary regurgitation is usually asymptomatic. A few patients develop symptoms and signs of RV dysfunction–induced HF (eg, dyspnea, exercise intolerance, peripheral edema, hepatic congestion).
Palpable signs are attributable to pulmonary hypertension and RV hypertrophy. They include a palpable pulmonic component (P2) of the second heart sound (S2) at the left upper sternal border and a sustained RV impulse that is increased in amplitude at the left middle and lower sternal border.
Auscultation
High-pitched, early diastolic decrescendo murmur
On auscultation, the first heart sound (S1) is normal. The S2 may be split or single. When split, P2 may be loud and audible shortly after the aortic component of S2 (A2) because of pulmonary hypertension, or P2 may be delayed because of increased RV stroke volume. S2 may be single because of prompt pulmonary valve closing with a merged A2-P2 or, rarely, because of congenital absence of the pulmonary valve. An RV third heart sound (S3), fourth heart sound (S4), or both may be audible with RV dysfunction–induced HF or RV hypertrophy; these sounds can be distinguished from left ventricular heart sounds because they are located at the left parasternal fourth intercostal space and because they grow louder with inspiration.
The murmur of PR due to pulmonary hypertension is a high-pitched, early diastolic decrescendo murmur that begins with P2 and ends before S1 and that radiates toward the mid-right sternal edge (Graham Steell murmur); it is heard best at the left upper sternal border with the diaphragm of the stethoscope while the patient holds the breath at end-expiration and sits upright.
The murmur of PR without pulmonary hypertension is shorter, lower-pitched (rougher in quality), and begins after P2. Both murmurs may resemble the murmur of aortic regurgitation but can be distinguished by inspiration (which makes the PR murmur louder) and by Valsalva release. After Valsalva release, the PR murmur immediately becomes loud (because of immediate venous return to the right side of the heart), but the aortic regurgitation murmur requires 4 or 5 beats to do so. Also, a soft PR murmur may sometimes become even softer during inspiration because this murmur is usually best heard at the second left intercostal space, where inspiration pushes the stethoscope away from the heart. In some forms of congenital heart disease, the murmur of severe PR is quite short because the pressure gradient between the pulmonary artery and the right ventricle equalizes rapidly in diastole.
Mixed pulmonary stenosis and insufficiency, as in the case of a deteriorating bioprosthetic valve or a right ventricle to pulmonary artery conduit, can be heard as a to-fro murmur in both systole and diastole.
Diagnosis of Pulmonary Regurgitation
Echocardiography
Pulmonary regurgitation is usually incidentally detected during a physical examination or Doppler echocardiography performed for other reasons. Mild PR is a common echocardiographic finding that requires no intervention.
Establishing the severity of pulmonary regurgitation by echocardiography can be challenging; criteria exist but are most useful when regurgitation is clearly severe (with diastolic flow reversal in the branch pulmonary arteries, a pressure half-time of 100 msec or less, and a wide color Doppler jet), or clearly mild (small color jet with minimal or no flow reversal in the main pulmonary artery). Cardiac MRI can be used to quantify the regurgitant fraction and more precisely grade the severity, along with quantifying the presence and degree of right ventricle dilation (1, 2).
An ECG and chest radiograph are usually also obtained. ECG may show signs of RV hypertrophy; chest radiograph may show RV enlargement and evidence of conditions underlying pulmonary hypertension.
Diagnosis references
1. Zoghbi WA, Asch FM, Bruce C, et al. Guidelines for the Evaluation of Valvular Regurgitation After Percutaneous Valve Repair or Replacement: A Report from the American Society of Echocardiography Developed in Collaboration with the Society for Cardiovascular Angiography and Interventions, Japanese Society of Echocardiography, and Society for Cardiovascular Magnetic Resonance [published correction appears in J Am Soc Echocardiogr 2019 Jul;32(7):914-917. doi: 10.1016/j.echo.2019.05.013.]. J Am Soc Echocardiogr 2019;32(4):431-475. doi:10.1016/j.echo.2019.01.003
2. Zoghbi WA, Enriquez-Sarano M, Foster E, et al. Recommendations for evaluation of the severity of native valvular regurgitation with two-dimensional and Doppler echocardiography. J Am Soc Echocardiogr 2003;16(7):777-802. doi:10.1016/S0894-7317(03)00335-3
Treatment of Pulmonary Regurgitation
Treatment of cause
Sometimes pulmonary valve replacement (PVR)
Treatment is management of the condition causing pulmonary regurgitation, particularly when pulmonary hypertension is the cause.
Pulmonary valve replacement is an option if RV dilation or dysfunction develops, particularly if the patient has symptoms. Pulmonary valve replacement is the treatment of choice for patients with moderate or greater PR after intervention for pulmonary stenosis, who have right ventricle dilation and symptoms or progressive decrease in exercise capacity. Finally, pulmonary valve replacement is commonly performed in patients after initial tetralogy of Fallot repair, particularly when a transannular patch is used (1). Surgical and transcatheter techniques are available for pulmonary valve replacement, depending upon patient characteristics and specific anatomic considerations.
Treatment reference
1. Stout KK, Daniels CJ, Aboulhosn JA, et al. 2018 AHA/ACC Guideline for the Management of Adults With Congenital Heart Disease: A Report of the American College of Cardiology/American Heart Association Task Force on Clinical Practice Guidelines [published correction appears in Circulation 2019 Apr 2;139(14):e833-e834. doi: 10.1161/CIR.0000000000000683]. Circulation 2019;139(14):e698-e800. doi:10.1161/CIR.0000000000000603
Key Points
In adults, pulmonary regurgitation (PR) is usually caused by pulmonary hypertension.
Hemodynamic consequences are usually due to the cause rather than PR itself.
Heart sounds when PR is due to pulmonary hypertension include a high-pitched, early diastolic decrescendo murmur that begins with P2 and ends before S1 and that radiates toward the mid-right sternal edge; it is heard best at the left upper sternal border while the patient holds the breath at end-expiration and sits upright. The murmur of PR without pulmonary hypertension is shorter, lower-pitched, and begins after P2.
Treatment is directed at the cause; valve replacement is usually not needed except in patients with congenital heart disease and prior pulmonary valve intervention.
