Mitral Mechanical Prosthetic Valve Thrombosis Four Years After Discontinuing Anticoagulation: A Case Report

Abstract

A 40 years lady who underwent a mitral valve replacement with a mechancial prosthesis nine years ago, stopped oral anticoagulants totally. She was asymptomatic and doing her field job with good exercise tolerance for 4 years without any anticoagulation or follow-up and presented now with acute pulmonary edema due to prosthetic valve thrombosis. Echocardiography revealed a large clot on the mitral valve and increased Doppler gradients across the valve. She was given intravenous streptokinase for 28 hours with relief of symptoms, re-appearance of prosthetic valve click and normalisation of flow velocities. She was prescribed oral acenocoumarol and discharged in a stable condition. CASE:Mrs. N, a 40 years lady was admitted with a two day history of Class IV dyspnea and was diagnosed to have mitral prosthetic valve thrombosis. She had undergone mitral valve replacement with a 27mm Medtronic Hall prosthesis for severe rheumatic mitral regurgitation in 2005; a permanent pacemaker was implanted when she developed complete heart block postoperatively. She was put on acenocoumarol and was on follow-up until 2011with an INR between 2 and 2.5. She discontinued oral anticoagulants and all drugs from August 2011 but reported no complaints -she had fair exercise tolerance and worked as a health worker which entailed field visits. She noticed mild dyspnea, but continued her work for the past 3 weeks, and was admitted now with acute pulmonary edema. The prosthetic valve click was muffled and the ECG showed a paced rhythm. Echocardiogram revealed decreased mobility of the mitral prosthesis with a large clot attached to it. The mitral flow gradients were very much increased with a peak gradient of 60 mm.Hg. And a mean gradient of 40 mm. Hg. She also had moderate aortic regurgitation and pulmonary hypertension with tricuspid regurgitation. The ejection fraction was 61.A diagnosis of prosthetic valve thrombosis was made and she was given intravenous streptokinase -2.5 lakh units as an intravenous bolus followed by an infusion of 1 lakh units per hour (for 28 hours). She was administered IV frusemide and sedation on admission in the ICCU. Acenocoumarol was also started at a dose of 2mg daily. By next day morning, she was better, the mitral valve click was well heard and echocardiography revealed a well-functioning mitral prosthesis with acceptable flow gradient -a peak of 8 and a mean of 3. Thrombus was not visible. She was administered enoxaparin 0.6mg bid for 5 days for the oral anticoagulant to take effect. The patient was discharged, in an asymptomatic condiction, and with fair effort tolerance, after 9 days, on acenocoumarol 2mg. daily and aspirin 75 mg.