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.