[Surgical treatment of chronic thromboembolic pulmonary hypertension]

Chronic thromboembolic pulmonary hypertension is a rare but underdiagnosed disease. The development of imaging played a crucial role for the screening and the decision of operability over the past few years. Indeed, chronic thromboembolic pulmonary hypertension is the only type of pulmonary hypertension with a potential curative treatment: pulmonary endarterectomy. It is a complexe surgical procedure performed under cardiopulmonary bypass with deep hypothermia and circulatory arrest. The aim of the procedure is to completely remove the scar tissue inside the pulmonary arteries down to the segmental and sub-segmental levels. Compared to lung transplantation, which carries a postoperative mortality of 15-20% and a 5-year survival of 50%, pulmonary endarterectomy is a curative treatment with a postoperative mortality of less than 3%. However, lung transplantation remains an option for young patients with inoperable distal disease or after pulmonary endarterectomy failure. Considering that medical history of deep venous thrombosis or pulmonary embolism is lacking in 25 to 50%, the diagnosis of chronic thromboembolic pulmonary hypertension remains challenging. The lung V/Q scan is useful for the diagnosis showing ventilation and perfusion mismatches. Lesions located at the level of the pulmonary artery, the lobar or segmental arteries may be accessible to surgical removal. The pulmonary angiogram with the lateral view and the pulmonary CT scan help to determine the level of the intravascular lesions. If there is a correlation between the vascular obstruction assessed by imaging and the pulmonary resistance, pulmonary endarterectomy carries a postoperative mortality of less than 3% and has a high rate of success. If the surgery is performed at a later stage of the disease, pulmonary arteriolitis developed mainly in unobstructed territories and participated in the elevated vascular resistance. At this stage, postoperative risk is higher.