Low Pulmonary Artery Pulsatility Index by Echocardiography Is Associated With Increased Mortality in Pulmonary Hypertension

Abstract

Pulmonary hypertension (PH) is a progressive pulmonary vascular disorder with elevated mortality risk. The pulmonary artery (PA) pulsatility index (PAPi) based on invasively acquired parameters has emerged as a hemodynamic risk predictor. Whether noninvasively derived PAPi (PA pulse pressure divided by right atrial pressure) is valuable is unclear. Consecutive patients undergoing transthoracic echocardiography for known or suspected PH were included with conventional echocardiographic measures of PA systolic, PA diastolic, and estimated right atrial pressures. In those patients with PH (mean PA pressure > 20mm Hg), PAPi was divided into 3 groups: <1.5, 1.5 to 3, and >3. Mortality was assessed over 5years. Of 1,045 patients enrolled, 64% had PH. Patients with the lowest PAPi had higher N-terminal-pro hormone B-type natriuretic peptide levels, larger right ventricles (RVs), worse RV systolic function, and greater degrees of tricuspid regurgitation. In patients with PH, PAPi was inversely proportional to the risk of death, with PAPi <3 associated with a 1.96-fold increased risk of death (95% CI, 1.45-2.64, P<.0001). At multivariate analysis, RV longitudinal systolic strain (hazard ratio [HR]=1.45, 1.24-1.71; P<.0001), PAPi <3 (HR=1.76, 1.31-2.37; P=.0002), and the presence of a pericardial effusion (HR=1.64, 1.20-2.26 P=.003) were independently associated with increased mortality. In age- and sex-adjusted models, PAPi was incremental to PA compliance. In patients with PH, low PAPi derived noninvasively by transthoracic echocardiography is associated with markers of right heart failure, RV dysfunction, and worse survival. PAPi could be incorporated into the conventional echo parameters reported in patients with PH and may be a useful predictor of outcome.