Abstract
BackgroundAnticoagulation therapy for mechanical prosthetic valves is limited to vitamin K antagonists, unfractionated heparin and low-molecular-weight-heparin. Other forms of anticoagulation are either contraindicated or have not been well studied. Hence, anticoagulation for preexisting mechanical valves is controversial if vitamin K antagonists are contraindicated. We present a case involving an end-stage-renal disease patient with both mitral and aortic mechanical valves who developed warfarin-induced calciphylaxis.Case presentationA 72-year-old male with history of end-stage renal disease, chronic atrial fibrillation and rheumatic heart disease status post mitral and aortic valve replacements presented with complaints of left thigh erythema with skin induration. Despite multiple antibiotic regimens for presumed cellulitis, the skin lesions progressed to necrotic ulcers. A biopsy revealed evidence of calciphylaxis; a lethal condition typically associated with renal disease. The patient was on warfarin for anticoagulation of his mechanical heart valves as well as prophylactically for atrial fibrillation. Warfarin contributes to the development of calciphylaxis and needed to be exchanged to avoid progression of the ulceration. The only other acceptable option for long-term anticoagulation was subcutaneous unfractionated heparin but this approach was not taken. The patient suffered from further sequelae of calciphylaxis and eventually expired.ConclusionCalciphylaxis is a rare, serious disorder that presents with skin ischemia and necrosis mainly in end-stage renal disease patients. The pathogenesis and treatment are poorly understood and the prognosis remains grave. It is proposed that certain medications, including warfarin, contribute to its evolution. The optimal anticoagulation therapy in those with concomitant warfarin-induced calciphylaxis and mechanical valves is undetermined. Further studies are essential to establish new anticoagulation regimens in these devastating circumstances.
Highlights
Anticoagulation therapy for mechanical prosthetic valves is limited to vitamin K antagonists, unfractionated heparin and low-molecular-weight-heparin
We present a case involving an end-stage-renal disease (ESRD) patient with both mitral and aortic mechanical valves who developed Vitamin K antagonist (VKA)-induced calciphylaxis
Dabigatran is the sole direct oral anticoagulant (DOAC) that was compared to warfarin in a population of patients with mechanical valves
Summary
Antithrombotic therapy in patients with mechanical heart valves continues to be a serious challenge. The choices are limited and problems may appear when patients have contraindications to the currently approved agents. In ESRD patients suffering from calciphylaxis, warfarin and enoxaparin cannot be used as warfarin intensifies the disease burden and enoxaparin at therapeutic dosing was not studied in patients with low CrCl. Newer LMWH agents seem promising since they do not bioaccumulate in renal patients. Further studies involving new LMWH agents and patients with CrCl < 30 mL/min are needed to determine the utility of LMWH in ESRD. Research exploring the effect of other DOACs on the anticoagulation of mechanical heart valves are imperative for determining the optimal antithrombotic regimen in the future. All authors read and approved the final manuscript. Ethics approval and consent to participate Not applicable. Springer Nature remains neutral with regard to jurisdictional claims in published maps and institutional affiliations
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