Responders included more IPAH patients (81.5 vs. 51.7%), shorter PAH history, lower NT-proBNP levels [947 (334, 1,736) vs. 1,840 (957, 2,588) pg/mL] and smaller RAA [24 (19, 33) vs. 28 (22, 37) cm2]. This evidence concerns the gene NPPB and idiopathic pulmonary arterial hypertension.