Chronic thromboembolic pulmonary hypertension: A comprehensive review of pathogenesis, diagnosis, and treatment strategies.

Chronic thromboembolic pulmonary hypertension (CTEPH) is part of group 4 of the pulmonary hypertension (PH) classification and generally affects more than a third of patients referred to PH centers. It is a three-compartment disease involving proximal (lobar-to-segmental) and distal (subsegmental) pulmonary arteries that are obstructed by persistent fibrothrombotic material, and precapillary pulmonary arteries that can be affected as in pulmonary arterial hypertension. It is a rare complication of pulmonary embolism (PE), with an incidence of around 3% in PE survivors. The observed incidence of CTEPH in the general population is around six cases per million but could be three times higher than this, as estimated from PE incidence. However, a previous venous thromboembolic episode is not always documented. With advances in multimodality imaging and therapeutic management, survival for CTEPH has improved for both operable and inoperable patients. Advanced imaging with pulmonary angiography helps distinguish proximal from distal obstructive disease. However, right heart catheterization is of utmost importance to establish the diagnosis and hemodynamic severity of PH. The therapeutic strategy relies on a stepwise approach, starting with an operability assessment. Pulmonary endarterectomy (PEA), also known as pulmonary thromboendarterectomy, is the first-line treatment for operable patients. Growing experience and advances in surgical technique have enabled expansion of the distal limits of PEA and significant improvements in perioperative and mid- to long-term mortality. In patients who are inoperable or who have persistent/recurrent PH after PEA, medical therapy and/or balloon pulmonary angioplasty (BPA) are effective treatment options with favorable outcomes that are increasingly used. All treatment decisions should be made with a multidisciplinary team that includes a PEA surgeon, a BPA expert, and a chest radiologist.