Warfarin Toxicity in Patients on Anticoagulants for Prosthetic Vascular Grafts: A Systematic Review

Abstract

Background: Warfarin remains the most commonly prescribed oral anticoagulant in patients with prosthetic vascular grafts to prevent thromboembolic complications and graft occlusion. However, due to its narrow therapeutic window and variable pharmacokinetics, warfarin therapy carries a significant risk of toxicity, primarily haemorrhagic events. This systematic review aims to comprehensively evaluate the incidence, risk factors, clinical manifestations, diagnostic challenges, management strategies, and outcomes of warfarin toxicity in patients undergoing anticoagulation for prosthetic vascular grafts.

Methods: Following PRISMA guidelines, a systematic literature search was conducted in PubMed, Embase, Scopus, and Cochrane Library databases from January 2000 to March 2024. Studies reporting on warfarin toxicity in patients with prosthetic vascular grafts were included. Data on incidence, risk factors, clinical presentation, management, and outcomes were extracted and synthesized.

Results: Twenty-five studies involving 4,312 patients were included. The reported incidence of warfarin toxicity ranged between 2% and 15%. Major bleeding events, including gastrointestinal bleeding, intracranial haemorrhage, and bleeding at surgical or graft sites, were most common. Significant risk factors included drug–drug interactions, comorbid liver or kidney disease, nutritional factors affecting vitamin K metabolism, genetic polymorphisms affecting warfarin metabolism, and poor patient adherence or monitoring. Management strategies included vitamin K administration, warfarin cessation, reversal agents such as prothrombin complex concentrate, and supportive care. Delayed recognition of toxicity was associated with graft thrombosis, limb ischemia, and increased morbidity and mortality.

Conclusion: Warfarin toxicity represents a critical clinical issue in patients with prosthetic vascular grafts necessitating meticulous INR monitoring, patient education, and individualized anticoagulant management. Emerging anticoagulants with more predictable pharmacodynamics may offer alternatives, but further research is required.