Upfront riociguat and ambrisentan combination therapy for newly diagnosed pulmonary arterial hypertension: A prospective open-label trial.

Background: Initial combination therapy with an endothelin receptor antagonist (ERA) and riociguat in pulmonary arterial hypertension (PAH) has limited supporting data.

Methods: We performed a prospective, single-arm, open-label trial of riociguat, and ambrisentan for incident PAH patients in functional class III. The primary endpoint was pulmonary vascular resistance (PVR) at 4-months.