Hemostatic alterations in splenectomized and non-splenectomized patients with β-thalassemia/hemoglobin E disease

Abstract

β-Thalassemia/hemoglobin (Hb) E is a hereditary hemolytic anemia with varying degrees of severity. Severely affected patients are treated with blood transfusion and/or splenectomy in order to maintain an optimum level of hemoglobin for normal growth and physical activities. As thrombosis has been observed among splenectomized patients, we have investigated alterations in coagulation and fibrinolysis in β-thalassemia/Hb E patients. Plasma levels of prothrombin, fibrinogen, factors V, VII, VIII, IX and XI, protein C, protein S, thrombin activatable fibrinolysis inhibitor (TAFI) and prothrombin fragment 1 + 2 were determined in 61 patients (21 non-severe non-splenectomized, 18 severe non-splenectomized, 22 severe splenectomized) and 28 healthy individuals. Serum levels of D-dimer, ferritin, aspartate transaminase and alanine transaminase were also measured. All severe patients received regular blood transfusion. Prothrombin fragment 1 + 2 and D-dimer were significantly elevated in splenectomized patients compared to the healthy control subjects, whereas levels of proteins C, protein S, TAFI, fibrinogen, and factors V and VIII in the splenectomized groups were statistically lower than those in control group. There are no statistical differences for the other parameters measured between patients and controls. Coagulation tests showed only significantly reduction in TAFI and factor V and VIII levels in severe splenectomized group in comparison with severe non-splenectomized patients. These results demonstrate the existence of a low grade consumptive coagulopathy among blood-transfused splenectomized patients with severe clinical manifestations, indicating that these patients may have a higher risk for thrombosis than comparable patients with intact spleen.