Hypercoagulable state in five thalassemia intermedia patients.

Fifty-three patients of thalassemia intermedia and 40 controls were studied for clinical evidence of thrombosis and laboratory evidence of hypercoagulable state. Thrombotic episodes were detected in 5 (9.4%) patients. Two of these 5 patients with thrombosis were splenectomized. Laboratory evaluation showed presence of thrombocytosis in 8 (15%), 5 of these were splenectomized. Platelet hyperaggregation was detected in 12 (22.2%) patients. Although rate of aggregation was slow in 7 (13.2%) patients, degree of aggregation was normal in these 7 patients and platelet hypoaggregation was not detected in any patient. Level of coagulation inhibitors protein C and protein S, and antithrombin III were decreased in 31 (58.4%) patients. There was no correlation between low level of protein C and protein S with hepatic dysfunction and iron overload. Antithrombin III level was decreased only in 8 (15%) patients. There was a statistically significant association between the lower level of this inhibitor and hepatic dysfunction. In conclusion, this study provides evidence for the existence of a chronic hypercoagulable state in patients with beta thalassemia intermedia, and suggests that expression of a procoagulant surface by thalassemia intermedia red blood cells may be the major underlying factor giving rise to platelet and coagulation inhibitor abnormalities in these patients. These alterations are not related to iron overload or hepatic dysfunction.