Diagnosis of chronic thromboembolic pulmonary hypertension.

Chronic thromboembolic pulmonary hypertension (CTEPH) is a severe complication of acute pulmonary embolism (PE), affecting approximately 2.7% of PE survivors. CTEPH results from persistent obstruction of the proximal pulmonary arteries by organized fibrotic clots, in combination with a secondary microvasculopathy, leading to increased pulmonary vascular resistance and progressive right heart failure. The mechanisms precluding a complete resolution of PE are not yet fully understood and include chronic inflammation, impaired fibrinolysis and coagulation abnormalities. Chronic thromboembolic pulmonary disease is the broader term for symptomatic patients with mismatched perfusion defects and signs of chronic thrombi on pulmonary vascular imaging, after at least 3 months of therapeutic anticoagulation, with CTEPH specifically referring to those with pulmonary hypertension. In patients with persistent dyspnea after PE or with PH, the diagnosis of CTEPH is suspected when ventilation/perfusion lung scan shows mismatched perfusion defects and is confirmed by comprehensive right heart catheterization and imaging with CT pulmonary angiography and/or digital subtraction angiography, which ought to be performed at centers with CTEPH expertise. Indeed, early referral to expert centers with experienced multidisciplinary teams ensures accurate diagnosis and tailored treatment, ultimately improving outcomes for CTEPH patients.