ABSTRACT
Chronic thromboembolic pulmonary hypertension (CTEPH) is a distinct and potentially curable form of pulmonary hypertension that develops following incomplete resolution of acute pulmonary embolism, leading to persistent fibrotic obstruction of the pulmonary arteries and progressive microvascular disease. Although CTEPH has traditionally been assessed using steady-flow hemodynamic parameters such as mean pulmonary arterial pressure and pulmonary vascular resistance, growing evidence suggests that pulmonary artery stiffness and altered vascular biomechanics are critical contributors to disease severity, right ventricular dysfunction, and patient outcomes. This narrative review summarizes current knowledge on the structural remodeling and biomechanical behavior of pulmonary arteries in CTEPH, with emphasis on changes affecting arterial compliance, impedance, and right ventricle–pulmonary artery coupling. Key mechanisms include thrombus organization, endothelial dysfunction, smooth muscle cell proliferation, extracellular matrix deposition, and mechanobiological feedback loops that reinforce vascular stiffening. The review further discusses available experimental and computational approaches used to characterize pulmonary vascular mechanics and highlights the clinical relevance of biomechanical markers in improving prognostic stratification and therapeutic decision-making. Finally, it outlines gaps in current evidence regarding reversibility of vascular stiffness and the long-term impact of surgical, interventional, and medical therapies, supporting the need for integrated biomechanical assessment in future CTEPH research and management.