Platelet survival in patients with beta-thalassemia

Thromboembolic events associated with significant morbidity and mortality have been observed in patients with beta-thalassemia major (TM). These include arterial as well as venous thrombosis and the development of early arteriosclerosis. To elucidate the possibility that TM patients may develop a hypercoagulable state we carried out a study of platelet kinetics on ten patients with TM and four patients with thalassemia intermedia (TI). Autologous platelets were labeled with indium-111-oxine, and the platelet lifespan (PLS) was determined. A significant shortening of PLS was observed in 13 out of 14 patients examined. The mean PLS (+/- 1 SD) in ten patients (8 TM, 2 TI) who underwent splenectomy was 107 +/- 36 hr (control splenectomized 248 + 51 hr) (P less than .001) and in four nonsplenectomized patients (2 TM, 2 TI) was 102 +/- 64 hr (control 224 + 23 hr) (P less than .01). The short PLS in addition to reported findings of increased circulating platelet aggregates and the decreased response of TM platelets to aggregating agents suggests in vivo platelet activation in thalassemic patients.