Long-term outcomes in pulmonary arterial hypertension in the first-line epoprostenol or first-line bosentan era

Background: The aim of this study was to describe the long-term outcomes in idiopathic pulmonary arterial hypertension (IPAH) treated with first-line bosentan or intravenous (IV) epoprostenol, and additional therapy as needed.

Methods: In a single-center, retrospective, longitudinal cohort, data on right heart catheterization, 6-minute walk distance (6MWD), disease progression and mortality were collected. Outcomes were assessed in first-line bosentan and first-line epoprostenol patients. To reduce selection bias due to differences between groups, two independent analyses were performed. First, a comparison was made of World Health Organization (WHO) Functional Class (FC) III patients. Second, to control for disease severity, a matched-pairs analysis was performed, with matching according to baseline cardiac output and exercise capacity and irrespective of FC at baseline.

Results: Thirty-seven IPAH patients initiated first-line bosentan treatment and 37 first-line IV epoprostenol. Twenty-nine of the bosentan patients and 16 of the IV epoprostenol patients were in WHO FC III; demographic profiles were similar, although hemodynamic measurements and 6MWD suggested more severe disease in the IV epoprostenol group at treatment initiation. At 1 and 3 years, median change in 6MWD for patients initiating bosentan was +54 m (95% confidence interval: -3 to 76) and +71 m (-123 to 116), respectively, and +92 m (17 to 128) and +142 m (-6 to 242) for those on IV epoprostenol. Absence of disease progression of WHO FC III at 1 and 3 years was 72% and 45% with bosentan and 75% and 44% with IV epoprostenol, respectively. Survival at 1 and 3 years was 93% and 89% with bosentan and 94% and 75% with IV epoprostenol, respectively. Results were confirmed in matched-pairs analysis of 16 bosentan and 16 IV epoprostenol patients with similar disease severity.

Conclusions: First-line epoprostenol treatment may lead to greater improvement in exercise capacity than first-line bosentan. However, these greater exercise improvements did not translate into longer time to disease progression or survival.