A Difficult Case of Calciphylaxis: Continuous Warfarin Use in a Patient with Calciphylaxis

Introduction: Calciphylaxis, or calcific uremic arteriolopathy (CUA), is a poorly understood, challenging complication of end-stage renal disease (ESRD) whose incidence has been increasing in the United States. Several risk factors have been associated with CUA, including warfarin. This article presents a difficult case of calciphylaxis that requires continued warfarin use in a patient with a history of antiphospholipid antibody syndrome with 50-60 episodes of deep venous thrombosis (DVTs), given unsuccessful trials with other anticoagulants in this patient. Case Description: A 46-year-old male with PMH of ESRD on peritoneal dialysis for 4 months, p-ANCA vasculitis, antiphospholipid syndrome with recurrent DVTs on warfarin, and hypertension presented with violaceous plaques and central eschar-like necrosis in bilateral distal upper inner thighs associated with significant tenderness. The clinical presentation raised suspicions of Calciphylaxis; treatment was initiated with sodium thiosulfate and sevelamer while continuing peritoneal dialysis. A skin biopsy revealed patchy, mild small-vessel vasculitis with calcification and epidermal ischemic necrosis, consistent with CUA. Initially, warfarin was temporarily halted. However, given the patient's unsuccessful trials with Eliquis in the past and his extensive history of venous thromboembolism, ongoing warfarin therapy was deemed necessary, particularly considering his history of heparin-induced thrombocytopenia and allergy to rivaroxaban. Following education on the risks and benefits associated with calciphylaxis and warfarin, the decision was made to continue warfarin. The patient was recommended to follow up with hematology at a tertiary facility for further recommendations on anticoagulation. Discussion: Once thought to be an uncommon condition, calciphylaxis has increased in frequency as more people require hemodialysis or peritoneal dialysis for ESRD. Given the poorer prognosis of CUA, which includes over 80% mortality in cases of severe CUA, prompt identification and treatment initiation are crucial. As anticoagulants, especially warfarin, have been linked with calciphylaxis, more research is required to understand the pathophysiology and to develop substitute interventions in a complex scenario such as this one where the risk of stopping warfarin outweighs the benefit.