New developments in the treatment of chronic thromboembolic pulmonary hypertension*** Pharmacological treatment of CTEPH

Author(s): Irene M Lang

Chronic thromboembolic pulmonary hypertension (CTEPH) is characterized by pulmonary arterial obstructions that typically result from non-resolving fibrotic organized pulmonary thromboemboli, causing elevated pulmonary vascular resistance, progressive pulmonary hypertension and, eventually, right heart failure. In more than 50% of patients, particularly those with a history of venous thromboembolism, CTEPH is a ‘surgical disorder’ meaning that the treatment of choice is a pulmonary endarterectomy, which restores pulmonary hemodynamics in a great majority of patients. However, in a recent registry, 36.4% of patients in major European expert centers were classified as non-operable, mainly due to surgically inaccessible thrombi or unacceptably high risk for surgery in general. Because of the observation of a secondary pulmonary vascular disease in some patients, pulmonary arterial hypertension (PAH)-targeted pharmacotherapies have been widely used in CTEPH patients – in up to 40% of patients in Europe – regardless of their operability status. However, the only randomized controlled trial that was powered to detect a difference between PAH-targeted drugs and placebo in CTEPH demonstrated that despite a moderate effect on hemodynamics, no improvement in 6-min walking distance was achieved. These data illustrate the great need for further trials of PAH-targeted drugs in CTEPH, or (mechanical) treatments to salvage the right ventricle.