Figure 1.

Current classification of PAH. Abbreviations: CCB, calcium channel blocker; mPAP, mean pulmonary arterial pressure; PVOD, pulmonary veno-occlusive disease; PCH, pulmonary capillary hemangiomatosis; DLCO, diffusing capacity of the lung for carbon monoxide; HRCT, high-resolution computed tomography; BMPR, bone morphogenic protein receptor type II.; ALK1, activin receptor-like kinase 1; ENG, endoglin; CAV1, caveolin-1; KCNK3, potassium channel, two-pore domain subfamily K member 3; and EIF2AK4, eukaryotic translation initiation factor 2α kinase 4 [2,4,5,6,8,10].