Higher rates of coronary angiography and revascularization following myocardial infarction may be associated with greater survival in the United States than in Canada. The CARS Investigators (Coumadin/Aspirin Reinfarction Study).
Significant differences are known to exist between the United States and Canada with respect to coronary catheterization and intervention. In a post hoc analysis, it was hypothesized that these differences may have the greatest impact on outcome in patients at risk for recurrent events such as those following myocardial infarction (MI).
The hypothesis was tested in a nonrandomized comparison of the catheterization and revascularization patterns for patients following acute MI in 7029 patients in the United States and 1774 patients in Canada who participated in the Coumadin/Aspirin Reinfarction Study (CARS). CARS tested the effectiveness of low dose warfarin in combination with acetylsalicylic acid (ASA) versus ASA alone in reducing cardiovascular morbidity and mortality.
Before study enrollment (median day 7 to 8), 84.5% of the American patients underwent coronary angiography compared with only 7.7% in Canada (P