Venous thromboembolism and hypercoagulability in splenectomized patients with thalassaemia intermedia

Thromboembolic phenomena have been described in patients with thalassaemia intermedia and major, although there are relatively few epidemiological dat a on the overall frequency of these complications. To obtain more insight i nto the risk and mechanism of venous thromboembolism in thalassaemia, the a ims of this study were: (i) to establish retrospectively the prevalence of thromboembolic events in a large group of adults with thalassaemia intermed ia and major during a follow up period of 10 years; (ii) to measure in subg roups of these patients sensitive markers of activation of coagulation and fibrinolysis enzymes; and (iii) to look for possible procoagulant mechanism s. A high prevalence of thromboembolic events was found, particularly in sp lenectomized patients with thalassaemia intermedia (29%). These patients ha d high plasma levels of markers of coagulation and fibrinolysis activation. Furthermore, thalassaemic red cells and erythroid precursors from splenect omized patients with thalassaemia intermedia had an enhanced capacity to ge nerate thrombin. To evaluate the role of splenectomy per se on procoagulant activity, we evaluated the capacity to form thrombin in healthy individual s who had been splenectomized for trauma. They produced the same amount of thrombin as non-splenectomized controls. In conclusion, the results of this study show the existence of a hypercoagulable state in splenectomized pati ents with thalassaemia intermedia and that their red and erythroid cells ar e capable of acting as activated platelets in thrombin generation.