When to refer a patient with chronic thromboembolic pulmonary hypertension for pulmonary endarterectomy.

Chronic thromboembolic pulmonary hypertension (CTEPH) is much more frequent than previously estimated, potentially occurring with an incidence of several thousand cases per year in Canada. Refinements in the surgical technique of pulmonary endarterectomy, the development of medical therapy and, more recently, the introduction of balloon pulmonary angioplasty have provided an increasing array of therapeutic options for this disease. CTEPH is related to the presence of chronic thromboembolic disease and the development of a secondary vasculopathy that leads to worsening pulmonary hypertension despite adequate anticoagulation, emphasizing the importance of early diagnosis and appropriate referral to achieve optimal therapeutic results. It is increasingly recognized that patients with CTEPH can present with acute on chronic pulmonary emboli. Recognition of the underlying chronic disease at the time of the acute presentation is important to ensure that these patients are adequately managed and followed with ventilation-perfusion scan and echocardiogram after their initial diagnosis of acute pulmonary emboli. Chronic thromboembolic disease should be suspected in the presence of idiopathic and/or recurrent pulmonary emboli, larger perfusion defects, longer times between symptom onset and diagnosis, a systolic pulmonary artery pressure > 50 mm Hg on echocardiogram and the presence of organized mural thrombi, mosaic parenchymal perfusion, and/or arterial web or bands on the computed tomography scan. Pulmonary endarterectomy is the treatment of choice for CTEPH. The surgery leads to major long-term clinical improvement and is curative in a large proportion of patients with resolution of the pulmonary hypertension.