CO-24 | BALANCING BLEEDING AND THROMBOSIS: SAFETY OF LOW-MOLECULAR-WEIGHT HEPARIN THROMBOPROPHYLAXIS IN PATIENTS WITH HEMOPHILIA UNDERGOING MAJOR SURGERY

S. Bergonzi^1|2|3, G. Murante^1|2|3, M. Capetta^1|2|3, F. Valeri^1|2, C. Dainese^1|2, A. Valpreda^3|4, R. Pastorino^3|4, F. Bocchi^3|4, B. Bruno^2|3, A. Borchiellini^1|2 | ¹Regional Centre for Hemorrhagic and Thrombotic Diseases, AOU Città della Salute e della Scienza, Torino, Italy; ²Division of Hematology, AOU Città della Salute e della Scienza, University of Turin, Italy; ³Department of Molecular Biotechnology and Health Sciences, University of Turin, Italy; ⁴Central Laboratory Baldi and Riberi, AOU Città della Salute e della Scienza, University of Turin, Italy

Background and Aims. In patients with hemophilia, the risk of venous thromboembolism (VTE) is traditionally considered low but may become clinically relevant in the setting of major surgery, particularly orthopedic and oncologic procedures. Current evidence is limited and heterogeneous. International guidelines recommend an individualized assessment of thrombotic and bleeding risk, favoring mechanical over pharmacological thromboprophylaxis, which should be reserved for selected patients under adequate factor replacement and without inhibitors. In this context, we aimed to retrospectively evaluate the safety of pharmacological thromboprophylaxis with low molecular-weight heparin (LMWH) in patients with hemophilia undergoing major surgery.
Materials and Methods. Medical records of 105 patients with moderate/severe hemophilia A or B followed at our center were retrospectively reviewed. Among these, 12 patients undergoing 18 major surgical procedures received postoperative LMWH thromboprophylaxis. Data were verified through comparison with the rare diseases registry.
Results. All included patients had severe hemophilia A and received perioperative factor replacement therapy. Trough factor levels during the first three postoperative days were ≥14%, and ≥11% thereafter. Patient characteristics, type of surgery, and trough levels are reported in Table 1. A single bleeding event occurred in a patient undergoing intestinal reanastomosis for previous rectal adenocarcinoma, who presented on postoperative day 4 with hematemesis and rectal bleeding, requiring LMWH discontinuation and transfusion support. No other major or minor bleeding events were observed. One patient developed a clinically evident VTE on postoperative day 8 despite LMWH thromboprophylaxis in the presence of multiple risk factors (high-risk inherited thrombophilia and smoking). No additional clinically evident thromboembolic events were observed.
Conclusions. In a setting of limited and conflicting evidence, all patients underwent individualized assessment of thrombotic and bleeding risk. They received adequate factor replacement therapy and were monitored through factor levels. In this context, LMWH thromboprophylaxis appeared safe in the vast majority of cases. These findings support the feasibility of a personalized approach to pharmacological thromboprophylaxis in patients with hemophilia undergoing major surgery, although prospective studies are warranted to confirm its safety.