A new method to estimate pulmonary vascular resistance using diastolic pulmonary artery-right ventricular pressure gradients derived from continuous-wave Doppler velocity measurements of pulmonary regurgitation

Pulmonary vascular resistance (PVR) is an important hemodynamic parameter in patients with heart failure, especially when the pulmonary arterial pressure is lower due to reduced stroke volume. Several echocardiographic methods to estimate PVR have been proposed, but their applications in patients with organic left-sided heart diseases have been limited. The aim of the present study was to examine the usefulness of our new method to estimate PVR (PVR_PR) based on the continuous-wave Doppler velocity measurements of pulmonary regurgitation in these patients. In 43 patients who underwent right heart catheterization, PVR_PR was calculated as the difference between the Doppler-derived early- and end-diastolic pulmonary artery (PA)-right ventricular (RV) pressure gradients divided by the cardiac output measured in the left ventricular outflow tract by echocardiography. The PVR_PR correlated well with invasive PVR (PVR_CATH) (r = 0.81, p < 0.001) without any fixed bias in Bland–Altman analysis. The conventional echocardiographic PVRs showed inadequate correlations with PVR_CATH, or a obvious overestimation of PVR_CATH. In the receiver operating characteristic analyses to determine the patients with abnormal elevation of PVR_CATH (>3 Wood units, WU), the area under the curve was the greatest for PVR_PR (0.964) compared to the conventional PVRs (0.649–0.839). PVR_PR had 83 % sensitivity and 100 % specificity at the optimal cut-off value of 3.10 WU in identifying patients with PVR_CATH >3 WU. Our simple and theoretical PVR_PR is useful for the noninvasive estimation of PVR.