The hypercoagulable state in thalassemia.

Thalassemia is a congenital hemolytic disorder caused by a partial or complete deficiency of alpha- or beta-globin chain synthesis. Homozygous carriers of beta-globin gene defects suffer from severe anemia and other serious complications from early childhood. The disease is treated by chronic blood transfusion. However, this can cause severe iron overload resulting in progressive organ failure. Some forms of alpha thalassemia are also associated with a similar clinical picture. Despite the difficulties associated with treatment, standards of care for thalassemic patients have improved in recent years, resulting in almost doubling of the average life expectancy. As a consequence, additional previously undescribed, complications are now being recognized. In particular, profound hemostatic changes have been observed in patients with beta-thalassemia major (beta-TM) and beta-thalassemia intermedia (beta-TI) and also in patients with alpha thalassemia (hemoglobin H disease). The presence of a higher than normal incidence of thromboembolic events, mainly in beta-TI, and the existence of prothrombotic hemostatic anomalies in the majority of the patients, even from a very young age, have led to the recognition of the existence of a chronic hypercoagulable state in thalassemic patients. Despite the appearance of numerous publications on the frequent occurrence of thromboembolic complications in thalassemia, this complication has not been emphasized or comprehensively reviewed. This review summarizes the current literature and discusses possible mechanisms of the lifelong hypercoagulable state that exists in thalassemia.