A 57 -year-old woman undergoes aortic valve replacement with a bileaflet mechanical valve for bicuspid aortic valve stenosis after an episode of syncope. Her past medical history is also significant for hypertension. Preoperative coronary angiogram showed no evidence of coronary artery disease and postoperative course was uncomplicated. Six months later, she comes to the physician for follow-up. Her medications include aspirin, warfarin, amlodipine, and candesartan. Transthoracic echocardiogram shows a mildly enlarged left atrium, left ventricular ejection fraction of 60%, a normally functioning mechanical aortic valve, and normal aortic root size. Which of the following is the best treatment option for this patient?
- A. Continue aspirin and discontinue warfarin [6%] .,
- B. Continue aspirin and warfarin with a goaiiNR of 2.0-3.0 [40%]
- C. Continue aspirin and warfarin with a goaiiNR of 2.5-3.5 [32%]
- D. Discontinue aspirin and continue warfarin with a goaiiNR of 2.0-3.0 [8%]
- E. Discontinue aspirin and continue warfarin with a goaiiNR of 2.5-3.5 [14%]
0 voters
Explanation:
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 mechanical aortic valve and no other risk factors (eg, atrial fibrillation, severe left ventricular dysfunction [ejection fraction S30%], prior thromboembolism, presence of hypercoagulable state), guidelines recommend long-term treatment with aspirin and warfarin to achieve a goaiiNR of 2.0-3.0.
(Choice A) Patients who cannot take warfarin due to bleeding complications may benefit from aspirin therapy alone.
(Choice C) INR goal of 2.5-3.5 is recommended in patients with mechanical mitral valves and those with mechanical aortic valves and associated risk factors.
(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 rates 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 highrisk features (eg, atrial fibrillation, left ventricular dysfunction [ejection fraction S30%], prior thromboembolism, presence of hypercoagulable state) and mechanical mitral valves is 2.5-3.5.