Pulmonary Hypertension in Left Heart Failure
Source: Enriquez-Sarano M, et al. J Am Coll Cardiol 1997;29:153-159.Although it is well known that the most common cause of pulmonary hypertension in adults is left heart failure, the genesis of pulmonary hypertension in patients with left heart disease is poorly understood. Thus, Enriquez-Sarano et al evaluated 102 patients with systolic left ventricular dysfunction (ejection fraction < 0.50) by Doppler echocardiography.
Systolic pulmonary artery pressure estimates from the tricuspid regurgitant jet velocity and inferior vena cava dynamics were 23-87 mmHg and were not independently related to ejection fraction or end systolic volume. The most powerful independent predictors of pulmonary artery systolic pressure were the mitral E wave deceleration time (r = -0.61) and the effective mitral regurgitant orifice (r = 0.50), which was based on regurgitant volume.
The authors conclude that pulmonary hypertension is common in patients with left ventricular dysfunction, but is highly variable and unrelated to the severity of left ventricular systolic dysfunction. Pulmonary hypertension is more closely related to diastolic dysfunction (shorter mitral E deceleration time) and the severity of mitral regurgitation (larger effective regurgitant orifice).
Diastolic dysfunction is believed to be important in diseases causing systolic left ventricular dysfunction but is complex and difficult to measure in humans. The short mitral E deceleration time, or the so-called "restrictive pattern," is usually indicative of high left ventricular end-diastolic pressure and reflects the global compliance of the left ventricle and atrium.
The mitral regurgitation in this study was functional and not due to leaflet disease. Such regurgitation is often difficult to detect clinically, which underscores the utility of Doppler echocardiography in patients with suspected left ventricular dysfunction. Fortunately, functional mitral regurgitation often decreases during vasodilator therapy as does pulmonary hypertension, further confirming their relationship.—mhc