Venous thromboembolism in hematopoietic stem cell transplantation: Incidence, pathogenesis, risk stratification, and management strategies

Venous thromboembolism (VTE) is an important but often underestimated complication in patients undergoing hematopoietic stem cell transplantation (HSCT), with a multifactorial pathogenesis involving endothelial injury, systemic inflammation, and venous stasis. This review provides a comprehensive overview of the current knowledge on VTE in the context of HSCT, including incidence patterns in autologous and allogeneic transplantation, underlying mechanisms, and key risk factors such as graft-versus-host disease (GVHD), central venous catheterization (CVC), prolonged hospitalization, and a history of thrombosis. We also summarize existing VTE and bleeding risk assessment models, and highlight the limitations of general VTE and bleeding risk when applied to transplant recipients. The review discusses emerging HSCT-specific models such as the HIGH-2-LOW and VTE and Bleeding in Marrow Transplant (VBMT) scores, and examines practical strategies for managing anticoagulation, particularly during chemotherapy-induced thrombocytopenia. Given the delicate balance between bleeding and thrombosis in this population, the review underscores the need for validated, transplant-specific clinical tools and evidence-based guidelines. By synthesizing recent advances and identifying knowledge gaps, this work aims to support more precise, individualized approaches to thrombosis prevention and management in HSCT recipients.