Test your medicine knowledge with the MKSAP challenge, in partnership with the American College of Physicians.

An 81-year-old man is evaluated in the office 3 days following a percutaneous coronary intervention with placement of a bare metal stent in the left anterior descending artery for angina refractory to maximal medical therapy. He indicates that he feels well except for palpitations that were not present before the procedure. Medical history is significant for hypertension and type 2 diabetes mellitus. He has no risk factors for or history of significant bleeding. Medications are aspirin, clopidogrel, lisinopril, atorvastatin, and metformin.

On physical examination, the patient is afebrile, blood pressure is 110/60 mm Hg, pulse rate is 65/min, and respiration rate is 12/min. BMI is 32. Estimated central venous pressure is not elevated. The heart has an irregularly irregular rhythm. Lungs are clear without crackles.

An electrocardiogram shows atrial fibrillation with a heart rate of 65/min and no acute ischemic changes. An echocardiogram demonstrates a left ventricular ejection fraction of 30%.

Which of the following is the most appropriate therapeutic regimen for this patient?

A. Aspirin and clopidogrel
B. Aspirin and dabigatran
C. Aspirin and warfarin
D. Aspirin, clopidogrel, and warfarin

MKSAP Answer and Critique

The correct answer is D. Aspirin, clopidogrel, and warfarin.

This patient should be treated with aspirin, clopidogrel, and warfarin (“triple therapy”). He has new-onset atrial fibrillation in the setting of recent bare metal stent placement for medically refractory angina. Patients with a bare metal stent should be treated with dual antiplatelet therapy for at least 1 month to allow endothelialization of the stent; with drug-eluting stents, the requirement for dual antiplatelet therapy is longer and depends upon the type of stent implanted. This patient is also at high risk of thromboembolic disease associated with atrial fibrillation. He has a CHA₂DS2-VASc score of 5 (2 points for age >75 years, 1 point each for diabetes mellitus, hypertension, and vascular disease). Therefore, oral anticoagulant therapy is also indicated. Although triple therapy with two antiplatelet agents and systemic anticoagulation is associated with a significant increase in bleeding risk, this regimen is appropriate treatment in this patient for at least 1 month until stent endothelialization can be assured, at which time he can be transitioned to only aspirin and an oral anticoagulant to decrease bleeding risk but provide adequate thromboembolic prophylaxis. If warfarin is used as an anticoagulant during triple therapy, careful maintenance of the INR within the recommended range of 2.0 to 2.5 in patients without mechanical valves may reduce the overall bleeding risk.

Aspirin and clopidogrel are inferior to oral anticoagulation for the prevention of stroke in patients with an indication for anticoagulation for thromboembolism prophylaxis in atrial fibrillation.

Treatment with aspirin and dabigatran is not optimal for two reasons. First, in the Randomized Evaluation of Long Term Anticoagulant Therapy (RE-LY) trial, there was a numeric excess of myocardial infarctions observed with dabigatran. More importantly, no data are available regarding the efficacy of aspirin and dabigatran for the prevention of stent thrombosis following an acute coronary syndrome.

Treatment with dual antiplatelet therapy is indicated in all patients with a coronary stent, with the recommended duration based on the underlying condition and type of stent placed. Therefore, treatment with aspirin and warfarin does not optimally prevent acute stent occlusion in a patient with stent placement.

Key Point

• Patients with atrial fibrillation and recent stent placement should be treated with appropriate systemic anticoagulation and antiplatelet therapy as determined by risk scoring and the type of stent placed.

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