Thrombotic Complications in Hemophilia: An Intricate Conundrum

Hemophilia A and hemophilia B are rare genetic disorders characterized by low plasma levels of coagulation factor VIII or factor IX, resulting in a bleeding tendency with a clinical severity proportional to the degree of the clotting factor deficiency. Although rare, hemophilia patients can paradoxically experience thrombotic events that complicate the clinical picture and the management by physicians operating at hemophilia treatment centers. Such thromboembolic complications, which can involve either the arterial or the venous districts, recognize various causes, including aging (due to the progress of care during the last three decades) and inherited and acquired (treatment-related) risk factors. These determinants often interact with each other to increase patients' susceptibility to thrombosis. In this narrative review, we summarize the current knowledge on the mechanisms, clinical presentation, and management of thrombotic complications in hemophilia patients.