Antithrombin (AT) III deficiency (now simply called antithrombin deficiency) refers to a congenital lack of the endogenous anticoagulant antithrombin.
Antithrombin deficiency is considered the least common of the three main anticoagulant deficiencies (the other two being protein C deficiency and protein S deficiency). Its incidence is thought to be ~1:2000-5000 1.
Antithrombin is a vitamin K-independent glycoprotein in the coagulation pathway. It is a major inhibitor of thrombin and other coagulation serine proteases, including factors Xa and IXa. The deficiency of antithrombin leads to a procoagulant state which is associated with an increased risk of thrombotic and embolic situations such as:
Radiology mainly plays a role in identifying thrombotic and embolic complications (see above). It is useful for the radiologist to be aware of the thrombotic risk associated with this deficiency.
Treatment and prognosis
Some publications favour the introduction of long-term oral anticoagulation treatment after the first thrombotic event 4.
- 1 Lipe B, Ornstein DL. Deficiencies of natural anticoagulants, protein C, protein S, and antithrombin. Circulation. 2011;124 (14): e365-8. doi:10.1161/circulationHA.111.044412 - Pubmed citation
- 2. Pabinger I, Brücker S, Kyrle PA et-al. Hereditary deficiency of antithrombin III, protein C and protein S: prevalence in patients with a history of venous thrombosis and criteria for rational patient screening. Blood Coagul. Fibrinolysis. 1993;3 (5): 547-53. Pubmed citation
- 3. Vittore CP, Demos TC. Hereditary deficiency of protein C, protein S and antithrombin III. Can Assoc Radiol J. 1996;47 (4): 251-6. Pubmed citation
- 4. Pabinger I, Schneider B. Thrombotic risk in hereditary antithrombin III, protein C, or protein S deficiency. A cooperative, retrospective study. Gesellschaft fur Thrombose- und Hamostaseforschung (GTH) Study Group on Natural Inhibitors. Arterioscler. Thromb. Vasc. Biol. 1996;16 (6): 742-8. Pubmed citation