Unilateral chronic thromboembolic pulmonary disease associated with combined inherited thrombophilia.

Chronic thromboembolic pulmonary hypertension (CTEPH) is considered to be an extreme variant of pulmonary thromboembolism. The underlying mechanisms for the failure of thrombus resolution are still unclear. In looking for inherited thrombophilia, an association with a lupus anticoagulant has been described repeatedly, and single cases of anticoagulant deficiencies (ie, antithrombin [AT], protein C, and protein S) have been reported. We describe a young patient with type I AT deficiency, the heterozygous prothrombin G20210A mutation, and unilateral chronic thromboembolic pulmonary disease presenting after a single thrombotic event. Pulmonary vascular patency was restored successfully by surgical pulmonary thromboendarterectomy. This case is unique because unilateral CTEPH is extremely uncommon, and it illustrates the severe clinical sequelae of the cosegregation of inherited thrombophilic defects.