Longitudinal echocardiographic evaluation predicts transplant-free survival better than baseline evaluation among PAH patients

Abstract

In pulmonary arterial hypertension (PAH), patients are serially investigated to stratify their risk of death and pulmonary transplantation with better discrimination at follow-up than baseline. The question whether right ventricular (RV) function by transthoracic echocardiography (TTE) is of prognostic significance at baseline or during follow-up is unanswered. To investigate the prognosis of PAH patients with several indices of RV size and function determined both at baseline and follow-up. Between 2002 and 2019, 126 PAH patients were included and treated in a single PAH center according to guidelines. In addition to regular risk stratification parameters, the following RV echocardiographic indices were measured at baseline and at 1-y follow-up: Tricuspid Annular Plane Systolic Excursion by M-mode (TAPSE, mm), RV annular peak systolic tissue Doppler S wave (S-TDI, cm/s), RV fractional area change (RV-FAC), RV end-diastolic area (RV-EDA), and the ratio of TAPSE/systolic pulmonary arterial pressure. Primary endpoints were death from all-cause or pulmonary transplantation. A majority (63%) were female, mean age 59 ± 18 yo. Baseline mean PAP was 42 (33, 52) mmHg from mainly due to idiopathic (28%) and connectivite tissue disease (24%). Under PAH treatment, NYHA (P < 0.01), NT-proBNP (P < 0.001) significantly improved. TAPSE (P < 0.01), S-TDI (P < 0.01), RV-FAC (P < 0.01) as well as TAPSE/systolic pulmonary arterial pressure (P = 0.03) were also improved. 24 patients died while 1 patient were transplanted at 3y F/U. At baseline, none of the echocardiographic indices were associated with the primary endpoint whereas TAPSE, S-TDI, RV-EDA as well as TAPSE/systolic pulmonary arterial pressure but not RV-FAC were of prognostic significance from Cox proportional hazard (Table 1). Right ventricular function by transthoracic echocardiography must be investigated at follow-up rather than baseline for PAH risk stratification.