Chronic Thromboembolic Pulmonary Hypertension-Therapeutic Options

Approximately 4% of all individuals that develop pulmonary embolism will go on to have chronic thromboembolic pulmonary hypertension (CTEPH). Patients with severe CTEPH will eventually be evaluated for thrombendarterectomy, the only curative treatment for this disease. However, only a subgroup of these patients is eligible for this invasive procedure. In addition, a number of patients will not benefit tremendously from thrombendarterectomy. Finally, thrombendarterectomy may not be possible for functional reasons. In these situations medical treatment, i.e. diuretics, oxygen and anticoagulation remains and is recommended. However, no proven specific e.g. vasodilating medical treatment has been demonstrated in CTEPH. Patients with CTEPH exhibit the same symptoms and a comparable prognosis compared with pulmonary arterial hypertension (PAH) patients. Although the occlusion of pulmonary vessels in CTEPH is caused by repetitive embolism histological similarities to PAH were observed in the pulmonary vascular bed, possibly a reaction to the developing high vascular pressure. Considering these similarities it would certainly make sense to study medical PAH treatment in patients with CTEPH. A few smaller studies exist, which do suggest beneficial effects of endothelin receptor antagonists, prostanoids and phosphodiesterase-5 antagonists in CTEPH. The evidence for the various forms of treatment of for CTEPH will be reviewed.