Abstract
Background
Antiplatelet therapy is the principal component of the antithrombotic regimen after
acute myocardial infarction. It remains unclear whether additional chronic oral anticoagulation
(OAC) improves outcomes. We set out to evaluate the risk and benefit of long-term
OAC after myocardial infarction.
Methods
We pooled 10 randomized clinical trials comparing warfarin-containing regimens (OAC)
with or without aspirin with non-OAC regimens with or without aspirin (No OAC) for
patients with recent infarction. The primary endpoint was all-cause mortality. Other
endpoints included recurrent infarction, stroke, and major bleeding. We calculated
the odds ratio (OR) (fixed effect, OR <1 indicates benefit for OAC) for death and
other ischemic and hemorrhagic complications at the longest interval of follow-up
available.
Results
Among 24,542 patients, 14,062 were assigned to OAC and 10,480 to no OAC. The patients
were followed for 3-63 months, for 89,562 patient-years. Death occurred in 2424 patients
(9.9%), 1279 OAC patients, and 1145 in the no OAC group, OR 0.97 (95% confidence interval
[CI], 0.88-1.05), P=.43. Similarly, there was no effect on recurrent infarction. Stroke occurred in 578
patients (2.4%), 271 in the OAC group and 307 in the no OAC group, OR 0.75 (95% CI,
0.63-0.89), P=.001. There was substantially more major bleeding (OR 1.83 [95% CI, 1.50-2.23], P <.001) in the OAC group. Separate analyses, performed for patients (n=11,920) randomized to aspirin versus aspirin and OAC yielded very similar results.
Conclusion
As compared with placebo or aspirin, OAC with or without aspirin does not reduce mortality
or reinfarction, reduces stroke, but is associated with significantly more major bleeding.
Keywords
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Article info
Footnotes
Funding: There were no funding sources for this manuscript.
Conflict of Interest: All authors state that they have no conflict of interest to disclose.
Authorship: All authors had complete access to the data and the analytical process. All authors contributed significantly to data collection, analysis, and manuscript review, and participated meaningfully in manuscript writing and editing.
Identification
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© 2010 Elsevier Inc. Published by Elsevier Inc. All rights reserved.
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- The ReplyThe American Journal of MedicineVol. 123Issue 11
- Anticoagulation Can Reduce Nonfatal Myocardial InfarctionThe American Journal of MedicineVol. 123Issue 11
- PreviewIn their recent meta-analysis, “Long-term Effect of Chronic Oral Anticoagulation with Warfarin after Acute Myocardial Infarction,” Haq et al1 found no effect of oral anticoagulation on myocardial infarction. In contrast, we previously found that, compared with aspirin alone, high-intensity oral anticoagulation plus aspirin resulted in a 45% reduction in myocardial infarction.2 In reconciling their results to ours, the authors suggest that they were including studies that were not available when our analysis was undertaken in 2005.
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