Figure 1.

The multifactorial etiopathogenesis of PAH. The pathogenesis of PAH implicates several molecular and cellular factors such as an increased proliferation of SMCs and ECs in the tunica intima and media. Risk factors (e.g., drugs) and genetic factors (e.g., dysfunctions in BMPR2) are also discussed to be involved in pathogenesis. PAH is characterized by an increased PVR and mean PAP ≥ 20 mmHg at rest, progressively leading to right ventricular hypertrophy (RVH), further resulting in right heart failure, loss of functional capacity and premature death. BMPR2, bone morphogenetic protein receptor type II; EC, endothelial cell; HIV, human immunodeficiency viruses, QoL, quality of life; SMC, smooth muscle cells; PAP, pulmonary arterial pressure; PVR, pulmonary vascular resistance (↑ = increased; ↓ = decreased).