Prognostic Significance of Echocardiographic Parameters in Predicting Early Decline in Patients with Pulmonary Arterial Hypertension

Abstract

Echocardiography is routinely used for screening and longitudinal monitoring of patients with pulmonary arterial hypertension (PAH). While several echocardiographic parameters have been explored to predict outcomes in PAH, they may be discrepant with other clinical findings. We sought to determine if echocardiographic parameters can predict early decline in PAH. We identified patients from the Houston Methodist PAH Clinic with WHO Group 1 PAH with an "Event," defined by initiation of IV prostacyclins, referral for transplant, or death between January 2016 and September 2019. We reviewed their echocardiographic parameters six months prior to the Event when they were clinically stable. We also reviewed these parameters in Group 1 PAH patients who remained stable during the study period as controls. Differences between groups were determined by Fisher's exact tests for categorical variables and Wilcoxon rank-sum test for continuous variables. We included 41 patients: 12 with an Event (3 died, 3 were referred for transplant, 6 were started on IV prostacyclins) and 29 without an Event. Of the 41 patients, 34 were women and 7 were men. Of the 12 with an Event, 11 were women and one was a man. Of the 29 without an Event, 26 were women and 3 were men. The average age was 46 in the Event group and 52 in the control group, p=0.50. The echocardiogram in the Event group was obtained an average of 197 days prior to the Event. The WHO functional class (FC) and six minute walk distance (6MWD) (420m vs. 393m, p=0.46) did not differ significantly between groups. The B type natriuretic peptide was significantly higher in the Event group (142 pg/ml vs. 42 pg/ml, p=0.01). Right atrial (RA) volume index (54ml/m2 vs. 29ml/m2, p=0.01), end diastolic left ventricular eccentricity index (LVEI) (1.3 vs. 1.0, p=0.001), end systolic LVEI (1.5 vs. 1.1, p=0.001), estimated pulmonary artery systolic pressure (PASP) (74mmHg vs. 52mmHg, p=0.02) and right ventricular (RV) basal dimension (5.0cm vs. 4.3cm, p=0.049) were significantly higher in the Event group. Left ventricular stroke volume (LVSV) (51ml vs. 69ml, p=0.045) was significantly lower in the Event group. RA volume index, end diastolic/systolic LVEI, PASP, RV basal dimension and LVSV predict early decline in Group 1 PAH patients even when they are deemed clinically stable based on FC and 6MWD.