Pulmonary (pulmonic) regurgitation
Pulmonary regurgitation is also called pulmonic regurgitation.
The majority of all adults exhibit a small pulmonary regurgitation, which is considered a normal finding. The regurgitation results in blood flowing back from the pulmonary artery into the right ventricle during diastole. The most common cause of abnormal pulmonary regurgitation is pulmonary hypertension. Table 1 presents the causes of pulmonary regurgitation.
Mild pulmonary regurgitation is a normal echocardiographic finding that requires no further investigation.
|Table 1. Causes of pulmonary regurgitation|
|Carcinoid heart disease|
|Tetralogy of Fallot|
|Iatrogenic (e.g complication of catheterization)|
|Congenital dysplasia/aplasia of the pulmonary valve|
|Idiopathic pulmonary artery dilation|
Pulmonary regurgitation results in right ventricular volume overload, which gradually causes right ventricular failure. The ventricle and RVOT (right ventricular outflow tract) become dilated, which further agravates the regurgitation. The proximal portion of the pulmonary artery may also be dilated in patients with pulmonary hypertension.
Echocardiography in pulmonary regurgitation
Echocardiography is the modality of choice for diagnosing pulmonary regurgitation. Continuous Doppler through the pulmonary valve reveals regurgitant blood flow in the parasternal short-axis view. Pressure gradient and pressure half time (PHT) are also estimated using continuous Doppler. A dense regurgitant jet with rapid deceleration (short PHT) is suggestive of severe regurgitation; the leakage usually ends early in diastole, which is evident by the spectral curve reaching the baseline before the end of diastole.