Chronic oral anticoagulation after acute MI reduces stroke risk
MedWire News: Chronic oral anticoagulation (OAC) with warfarin, with or without aspirin, after acute myocardial infarction (MI) reduces the risk for stroke but is associated with increased major bleeding, researchers report.
Chronic OAC does not reduce mortality or re-infarction compared with placebo or aspirin, however, report Sorin Brener and colleagues from New York Methodist Hospital, Brooklyn, USA.
Brener et al explain in The American Journal of Medicine that they pooled 10 randomized clinical trials comparing warfarin-containing regimens (OAC) with or without aspirin with non-OAC regimens with or without aspirin for patients with recent acute MI.
Among 24,452 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 in total. Deaths occurred in 2424 patients (9.9%), 1279 patients on OAC compared with 1145 in the no-OAC group, a non-significant difference. Similarly, there was no difference in the rate of recurrent infarction between these groups.
Stroke occurred in 271 patients in the OAC group versus 307 in the no OAC group, giving a significant OR of 0.75. There was significantly more major bleeding in the OAC group, at an OR of 1.83.
Subanalysis of 11,920 patients randomly assigned to aspirin versus aspirin and OAC yielded very similar results.
Brener and co-authors comment: “While our data are derived from a large cohort of patients, we did not have access to patient-specific data and could not identify subsets of patients in whom OAC may be beneficial.”
They add: “Dedicated clinical trials may be able to identify selected subsets of patients who could still benefit from OAC in the current era. These results do not exclude the possibility that carefully monitored INR at a moderate intensity may prevent the combination of ischemic events analyzed separately in this study.
“We see a need, based on our findings, for revisiting the American College of Cardiology/American Heart Association guidelines for postinfarction care with respect to OAC.”
MedWire (www.medwire-news.md) is an independent clinical news service provided by Current Medicine Group, a trading division of Springer Healthcare Limited. © Springer Healthcare Ltd; 2010
By James Taylor