Prognostic Value of Echocardiographic Variables Prior to and Following Initiation of Parenteral Prostacyclin Therapy: An Observational Study

Background: Echocardiographic parameters are used as prognostic markers in patients with pulmonary arterial hypertension (PAH) receiving parenteral (IV or subcutaneous [IV/SC]) prostacyclin therapy. However, data on how posttreatment echocardiographic results associate with outcomes are limited. Research Question: Are echocardiographic parameters pre- and post-parenteral prostacyclin therapy in patients with PAH associated with long-term outcomes? Study Design and Methods: In this retrospective cohort study, patients with PAH initiated on IV epoprostenol or IV/SC treprostinil therapy between 2007 and 2016 were included and followed up through May 31, 2020. Survival free from transplant was assessed from the time of IV/SC prostacyclin therapy initiation and from first follow-up echocardiogram following at least 90 days of therapy. Results: Patients with PAH initiated on IV/SC prostacyclin therapy (N = 118) were followed up for a median of 7.3 years. Survival was 86%, 79%, and 69% at 1, 2, and 3 years, respectively. Follow-up echocardiogram in 101 patients (median, 178 days; interquartile range, 140-273 days) showed improvement in five echocardiographic measures: right ventricular function, right ventricular systolic pressure, right ventricular diastolic diameter, left ventricular diastolic diameter, and tricuspid regurgitation (TR) severity. TR severity and pericardial effusion were associated with survival from IV/SC therapy initiation, whereas right ventricular diastolic diameter, right atrial (RA) size, TR severity, and inferior vena cava characteristics were associated with survival from first follow-up. In a multivariable analysis incorporating other prognostic measures at first follow-up, walk distance, functional class, N-terminal pro-B-type natriuretic peptide, and RA size resulted in the best fit model for survival. Interpretation: Echocardiographic variables improved following IV/SC therapy, and multiple echocardiographic measures associated significantly with survival, particularly when reassessed after at least 90 days of therapy. RA size in particular may be useful in prognostication in follow-up of patients with PAH on IV/SC therapy.