Echocardiographic prediction of pre- versus postcapillary pulmonary hypertension

Background: The differential diagnosis between pre- and postcapillary pulmonary hypertension (PH) is of major therapeutic relevance and thus requires optimal clinical probability assessment with echocardiography.

Methods: We prospectively analyzed 152 consecutive patients referred to a PH center over a 1-year period undergoing quasi-simultaneous (within 1 hour) echocardiography and right heart catheterization. Echocardiography was performed as usually recommended for the assessment of PH and left heart conditions. PH was defined as a mean pulmonary artery pressure ≥ 25 mm Hg. Postcapillary PH was diagnosed on the basis of a pulmonary capillary wedge pressure >15 mm Hg.

Results: Ten of 152 patients (7%) had no PH, 81 of 152 (53%) had precapillary PH, and 61 of 152 (40%) had postcapillary PH. The following five echocardiographic variables were found to predict precapillary PH: right heart chamber larger than the left (P = .0018), left ventricular eccentricity index > 1.2 (P = .0039), dilated inferior vena cava without inspiratory collapse (P = .0076), E/e' ratio ≤ 10 (P = .00001), and the right ventricle forming the heart apex (P = .0144). Beta coefficients from multiple logistic regression were significant for dilated inferior vena cava without inspiratory collapse (P = .0464) and E/e' ratio ≤ 10 (P = .0002). The score based on β coefficients, ranging from 3 to 34 points, resulted in optimal discrimination at >5, with a positive predictive value of 67.9% and a negative predictive value of 77.5% for precapillary PH.

Conclusion: Echocardiography enables a clinically satisfactory differential diagnosis between pre- and postcapillary PH.