Dabigatranへの変更後に生じた僧帽弁位機械弁の血栓弁

Mitral Mechanical Valve Thrombosis after Switching to Dabigatran

近年，直接経口抗凝固薬（direct oral anticoagulants：DOAC）が注目され，その適応症も広がりつつあるが，機械弁（mechanical heart valve：MHV）使用例に対してはいまだにwarfarinしか推奨されていない．MHVは生体弁に比べ耐久性に優れているが，弁の開閉部に血栓ができやすいデメリットがある．そのため，MHV使用例ではwarfarinを生涯服用する必要がある．しかしながら，再手術を望まない若い男性患者で本人の希望によりMHVを使用する機会はまだまだ多い．

The patient is a 76-year-old man who underwent aortic and mitral valve replacement 30 years ago, both with mechanical valves. He had been on anticoagulant therapy with warfarin, which was switched to dabigatran two years ago by his primary care physician. He developed shortness of breath afterward and was taken to the hospital with heart failure. Fluoroscopy of the valve revealed that one leaflet of the prosthetic mitral valve was immobile. The patient was diagnosed with a thrombosed valve and underwent an urgency repeat mitral valve replacement. He recovered uneventfully and was discharged without complication. During long years, some patients may have comorbidities and get frail. Medical principle may change, and various treatment methods with more and more complex indications may emerge. But in patients with mechanical heart valves, warfarin still remains the only choice for anticoagulation therapy.