Tbil and Dbil had a negative correlation with PVR in the POPH group (r = −0.394, P=0.031; r = −0.364, P=0.048, respectively) but positive correlation in the IPAH group (r = 0.218, P=0.003; r = 0.178, P=0.018, respectively). The gene discussed is PVR; the disease is idiopathic pulmonary arterial hypertension.