A 57-year-old woman undergoes mitral valve replacement with a mechanical valve for mitral stenosis. Preoperative angiogram shows no evidence of coronary artery disease. The postoperative course is uncomplicated. Transthoracic echocardiogram shows a moderately enlarged left atrium, left ventricular ejection fraction of 60%, and a normally functioning mechanical mitral valve. Which of the following is the best long-term treatment option for this patient?

Question

A 57-year-old woman undergoes mitral valve replacement with a mechanical valve for mitral stenosis.  Preoperative angiogram shows no evidence of coronary artery disease.  The postoperative course is uncomplicated.  Transthoracic echocardiogram shows a moderately enlarged left atrium, left ventricular ejection fraction of 60%, and a normally functioning mechanical mitral valve.  Which of the following is the best long-term treatment option for this patient?

Quizplus · Accepted Answer

11ec193a_976c_7e7c_853d_1f7678576f9b_MD0002_00 The risk of systemic thromboembolism (eg, stroke) is approximately 4% per patient per year in those with mechanical prosthetic valves with no anticoagulation, compared to about 2% in patients treated with aspirin and <1% in patients treated with warfarin. Patients with mechanical mitral valves have twice the risk compared to those with aortic valve prostheses. Therefore, long-term treatment with aspirin and warfarin is recommended for all patients with mechanical aortic or mitral valve replacement to reduce the rates of systemic thromboembolism. Current guidelines on the target International Normalized Ratio (INR) vary with the valve position (aortic vs mitral), type of mechanical valve, and associated comorbid conditions. In patients with a mechanical aortic valve and no other risk factors (eg, atrial fibrillation, severe left ventricular dysfunction [ejection fraction <30%], prior thromboembolism, presence of hypercoagulable state), guidelines recommend long-term treatment with aspirin and warfarin to achieve a goal INR of 2.0-3.0 (Choice A). INR goal of 2.5-3.5 is recommended in patients with mechanical mitral valves as well as those who have mechanical aortic valves and additional risk factors. < (Choice C) Patients who cannot take warfarin due to bleeding complications may benefit from aspirin therapy alone. (Choices D and E) Combined antiplatelet (aspirin) and anticoagulant (warfarin) therapy significantly reduces the risk of thromboembolism and mortality compared to anticoagulant therapy alone. Educational objective: Antithrombotic therapy with aspirin and warfarin is recommended for all patients with mechanical aortic or mitral valve replacement to reduce the rate of systemic thromboembolism. Target International Normalized Ratio (INR) for aortic valves without risk factors is 2.0-3.0. Target INR for mechanical aortic valves with high-risk features (eg, atrial fibrillation, left ventricular dysfunction [ejection fraction <30%], prior thromboembolism, presence of hypercoagulable state) and mechanical mitral valves is 2.5-3.5. < __________ References: Antithrombotic and thrombolytic therapy for valvular disease: antithrombotic therapy and prevention of thrombosis, 9th ed: American College of Chest Physicians evidence-based clinical practice guidelines. (http://www.ncbi.nlm.nih.gov/pubmed/22315272)

A 57-Year-Old Woman Undergoes Mitral Valve Replacement with a Mechanical