Thrombophilia, Thromboembolic Disease, and Antithrombotic Therapy

Abstract

Patients with a tendency to thrombosis are defined as having thrombophilia. The term “inherited thrombophilia” should be used for individuals with predisposing genetic defects. Hypercoagulability and thrombophilia are synonymous. Thrombophilia is usually suspected in patients with one or more of the following clinical features: idiopathic thrombosis, thrombosis at a young age, recurrent thrombosis, and thrombosis at an unusual site. Individuals who have laboratory abnormalities or clinical disorders that are known to predispose to thrombosis, but have not had an episode of thrombosis, are potentially thrombophilic. Prior to 1993, the diagnosis of a hereditary disorder could be established in only 10– 15% of younger patients presenting with venous thromboembolism (VTE). The only disorders known at this time were deficiencies of antithrombin (AT), protein C, and protein S. With the discovery of the factor V Leiden mutation (activated protein C [APC] resistance; see “Inherited Hypercoagulable States”) and, more recently, the prothrombin gene mutation, it is currently possible to define genetic risk factors in many younger patients with idiopathic venous thrombosis.