Pathological Process of PH

Pulmonary hypertension (PH) is a disorder of the cardiopulmonary system that affects pulmonary circulation and the right ventricle (RV). Despite diverse underlying causes, PH is generally characterized by excessive proliferation of vascular cells, extracellular matrix deposition, and accumulation of inflammatory cells within the pulmonary vessels, leading to increased pulmonary vascular resistance. Pathological features include endothelial dysfunction, abnormal cell signaling, and progressive remodeling of the arteriolar wall, with medial hypertrophy, intimal proliferation, and adventitial thickening. Metabolic changes and mitochondrial dysfunction are increasingly recognized as contributors to disease progression. As pulmonary artery pressure rises, the RV initially compensates by increasing wall thickness and output, but chronic overload eventually leads to right heart failure, making vascular remodeling and increased resistance central indicators of disease severity.