Managing anticoagulation in a patient with Calciphylaxis and mechanical valve: a therapeutic dilemma.

Background: Calciphylaxis is a rare, life-threatening vasculopathic syndrome most commonly seen in end-stage renal disease (ESRD) and associated with high mortality. Vitamin K antagonists complicate management in patients with mechanical valves by potentially exacerbating vascular calcification while remaining essential for thromboprophylaxis. Case Presentation: A 50-year-old woman with ESRD on hemodialysis and a mechanical mitral valve on warfarin presented with severe abdominal pain and rapidly progressive necrotic ulcers. Despite broad-spectrum antibiotics and sodium thiosulfate, lesions worsened. Biopsies were nondiagnostic; however, the clinical phenotype was consistent with calciphylaxis. A multidisciplinary team transitioned anticoagulation from warfarin to subcutaneous unfractionated heparin (UFH) (333 U/kg bolus, then 250 U/kg every 12 h). Anticoagulation was monitored with serial PTTs. Over two months, wounds stabilized with interval debridements, granulation improved, and no valve-related thromboembolic or bleeding complications occurred. Conclusion: In a mechanical-valve patient with ESRD and suspected calciphylaxis, sustained, full-dose subcutaneous UFH served as a pragmatic alternative to warfarin, allowing wound stabilization without short-term valve complications. Early recognition, multidisciplinary coordination, and individualized anticoagulation strategies are critical to balance thrombotic and calciphylaxis risks.