Hypercoagulability in splenectomized thalassemic patients detected by whole-blood thromboelastometry, but not by thrombin generation in platelet-poor plasma

Abstract

BackgroundThe mechanisms responsible for the increased thrombotic risk associated with thalassemia are still unclear. They might be related to the effects of red blood cell or endothelial cell derangements, increased numbers of platelets as well as abnormal plasma coagulation. Design and MethodsTo evaluate the relative role played by cells and plasma we investigated 169 patients with thalassemia by means of thromboelastometry and thrombin generation tests. Thromboelastometry measures indices of the viscoelastic properties of whole blood after activation of coagulation and is characterized by the clotting time, which may be considered as a conventional coagulation time, clot formation time, defined as the time needed for the clot to reach a fixed firmness, and the maximum clot firmness, defined as the maximal amplitude of the tracing. ResultsAll the thromboelastometry parameters determined in whole blood (including shortened clotting time and clot formation time, and increased maximum clot firmness), were consistent with hypercoagulability, especially in splenectomized patients. Conversely, thrombin generation as determined in platelet-poor plasma was not. ConclusionsThese findings point to blood cells and/or platelets rather than to plasma abnormalities as the most important determinants of the thrombotic risk observed in thalassemic patients who had been splenectomized. These results might have important diagnostic and therapeutic implications.

Hypercoagulability and thrombotic complications in hemolytic anemias

“…36 All the thromboelastometry parameters determined in whole blood, including shortened clotting time and clot formation time, and increased maximum clot firmness, were consistent with hypercoagulability, especially in splenectomized patients. However, thrombin generation determined in platelet-poor plasma was not significantly different from that in healthy individuals.…”

Alloimmunization to Red Cells and the Association of Alloantibodies Formation with Splenectomy Among Transfusion-Dependent β-Thalassemia Major/HbE Patients

“…Other negative effects include a raised risk of thrombotic complications and pulmonary hypertension, possibly due to the raised number of circulating platelets and immature red blood cells with alteration of the endothelial function, enhanced platelet activation, decreased levels of proteins C and S [16,17] Then, a progressive increase of awareness of these negative effects may have contributed to lower the tendency to perform splenectomy in these b-TM patients. Many studies have suggested that the rate of alloimmunization is higher after splenectomy [18].…”

Hypercoagulability in β-thalassemia: a status quo

“…Such risk-assessment models should be established for patients with thalassemia and could be used to identify high-risk patients and to target them for further testing and close follow-up. Several diagnostic tests are under investigation and could help further identify patients at highest risk, approaching an evidence-based medicine model [58]. Finally, evidence from observational studies should be carried forward to clinical trials, evaluating the role of transfusion, antiplatelet and anticoagulant therapy for the prevention of thrombotic events in thalassemia patients.…”