Pearl of the Month

How thin should we go?


 

An 88-year-old man with hypertension, chronic obstructive pulmonary disease, and atrial fibrillation presents with severe cerebral palsy and is diagnosed with a non–ST-elevation MI. He is found to have 90% left anterior descending artery occlusion and receives a drug-eluting stent. His current medications include warfarin, tiotropium, amlodipine, aspirin, and lisinopril. What anticoagulant therapy should he receive?

Dr. Douglas S. Paauw, University of Washington, Seattle

Dr. Douglas S. Paauw

A) Clopidogrel, warfarin, and aspirin

B) Clopidogrel and aspirin

C) Clopidogrel and warfarin

D) Warfarin

E) Warfarin and aspirin

This issue comes up frequently with our patients with atrial fibrillation who are on anticoagulation, then have a coronary event and have a stent placed. What is the best approach to anticoagulation? I think for this patient adding clopidogrel, continuing warfarin, and stopping aspirin would be the best of the options presented.

Elderly patients have a higher risk of bleeding. They also have a greater chance of accumulating cardiovascular disease (atrial fibrillation, cardiac allograft vasculopathy, and valvular disease) that requires anticoagulation. Dewilde et al. studied the difference in bleeding risk in patients who were on oral anticoagulants who then underwent a percutaneous coronary intervention.1 Patients were assigned clopidogrel alone or clopidogrel plus aspirin in addition to their oral anticoagulant (warfarin). There was a significant increase in all-cause mortality in the patients who received clopidogrel plus aspirin (P = .027), and no significant difference in cardiac mortality between the two groups. There was a much higher risk of bleeding (44.4%) in the patients receiving triple therapy, compared with the double-therapy group (19.4%; P less than .0001).

In a large meta-analysis of over 7,000 patients by D’Ascenzo et al., there was no difference in thrombotic risk between double and triple therapy, and lower bleeding risk in patients who received double therapy.2

In a recently published article, Lopes et al. looked at the benefits and risks of antithrombotic therapy after acute coronary syndrome or percutaneous coronary intervention in patients with atrial fibrillation.3 The study included 4,614 patients, all of whom received a P2Y12 inhibitor. In addition, they received either apixaban or warfarin, and either aspirin or placebo. The patients who received apixaban had a lower risk of bleeding than those receiving warfarin (P less than .001), and those receiving aspirin had a higher risk than those receiving placebo (hazard ratio, 1.89; P less than .001). Patients using the combination of apixaban plus placebo had the lowest event rate per 100 years (16.8), followed by warfarin plus placebo (26.7), then apixaban plus aspirin (33.6), with warfarin plus aspirin having the highest event rate (49.1). The conclusion for the study was that regimens with apixaban without aspirin had less bleeding and hospitalizations without increased ischemic events, compared with regimens of warfarin with or without aspirin.

I think it is best to avoid aspirin in patients who are anticoagulated with warfarin, and likely this extends to Xa inhibitors as well.

Pearl: Avoid using triple anticoagulant therapy by eliminating aspirin.

Dr. Paauw is professor of medicine in the division of general internal medicine at the University of Washington, Seattle, and serves as third-year medical student clerkship director at the University of Washington. Contact Dr. Paauw at [email protected].

References

1. Dewilde WJ et al. Use of clopidogrel with or without aspirin in patients taking oral anticoagulant therapy and undergoing percutaneous coronary intervention: An open-label, randomised, controlled trial. Lancet. 2013 Mar 30;381(9872):1107-15.

2. D’Ascenzo F et al. Meta-analysis of randomized controlled trials and adjusted observational results of use of clopidogrel, aspirin, and oral anticoagulants in patients undergoing percutaneous coronary intervention. Am J Cardiol. 2015 May 1;115(9):1185-93.

3. Lopes RD et al. Antithrombotic therapy after acute coronary syndrome or PCI in atrial fibrillation. N Engl J Med. 2019 Apr 18;380(16):1509-24.

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