Aspirin Unneeded With Anticoagulation/Clopidogrel After MI, PCI in AF

June 07, 2013

COPENHAGEN, Denmark — The addition of one antiplatelet agent to oral anticoagulation is sufficient in patients with atrial fibrillation (AF) who experience an MI or PCI, and the antiplatelet agent probably should be clopidogrel instead of aspirin, concluded a study of >12 000 patients from nationwide registries in Denmark[1].

Despite the common recommendation for triple antithrombotic therapy in patients with multiple indications for antithrombotic therapy, which would have added aspirin into the mix, "Our data suggest that triple-therapy-management regimens might be replaced with oral anticoagulation and clopidogrel without any additional risk of recurrent thrombotic events and a lower risk of bleeding," according to the authors, led by Dr Morten Lamberts (Copenhagen University Hospital Gentofte, Hellerup, Denmark).

Their findings, published online June 4, 2013 in the Journal of the American College of Cardiology, are based on data from 2001–2009, when oral anticoagulation meant vitamin-K antagonists like warfarin and clopidogrel was the state-of-the-art oral antiplatelet.

Therefore, "these results cannot necessarily be extrapolated to the newer direct thrombin and factor Xa inhibitors," notes Dr Steven M Markowitz (Cornell University Medical Center, New York, NY) in an accompanying editorial[2]. "It is probable that combining these new agents with dual antiplatelets would cause more bleeding than benefit," he writes.

"For patients with both AF and coronary disease, there is a paucity of information to guide rational decisions and very little evidence to support intensive anticoagulation with triple therapy." The current study, Markowitz writes, means that "physicians should have confidence to curtail triple therapy when oral anticoagulation is needed for AF."

The current study tracked 12 165 patients with AF who were hospitalized for MI or PCI in nationwide registries; about 61% were men, and the mean age was 75. Nearly two-thirds were treated with multiple antithrombotic drugs at baseline, and 38.3% received oral anticoagulation therapy.

Hazard Ratio (95% CI) for Outcomes Compared With Triple Therapy, by Antithrombotic-Therapy Group

End point Oral anticoagulation plus aspirin Oral anticoagulation plus clopidogrel Aspirin plus clopidogrel
All-cause mortality 1.52 (1.17–1.99) 0.87 (0.56–1.34) 1.60 (1.25–2.05)
MI/coronary death 0.96 (0.77–1.19) 0.69 (0.48–1.00) 1.17 (0.96–1.42)
Bleeding complications 0.69 (0.53–0.90) 0.78 (0.55–1.12) 0.48 (0.38–0.61)

Triple therapy=warfarin or phenprocoumon plus both clopidogrel and aspirin

The only significant hazard ratio for the end point of ischemic stroke was for dual antiplatelet therapy: 1.50 (95% CI 1.03-2.20).

The findings are consistent with those of the What is the Optimal Antiplatelet and Anticoagulant Therapy in Patients with Oral Anticoagulation and Coronary Stenting (WOEST) trial, which involved far fewer patients but was prospective and randomized. In the 573-patient trial, those who received oral anticoagulation plus clopidogrel after PCI with stents had significantly fewer bleeds than those also receiving aspirin. They also may have had fewer clinical events, although the trial was underpowered for those outcomes.

"In composite," writes Markowitz, "these two studies suggest dual anticoagulation with oral anticoagulation plus clopidogrel as a safer and perhaps equally effective strategy compared with triple therapy."

Neither Lamberts et al nor Markowitz had disclosures.

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