Catheterization after myocardial infarction and the mismeasure of un-American inactivity.

In this issue of the Journal, Batchelor et al. (1) compare the diagnostic yield of coronary angiography in the U.S. and Canadian patients enrolled in the Global Use of Strategies to Open Occluded Arteries in Acute Coronary Syndromes (GUSTO-1) trial. They defined yield as severe coronary artery disease (CAD), more specifically left-main or threevessel disease. The rates of angiography on the index hospital admission in the U.S. were 71%, as compared with only 27% in Canada. They expected that conservative use of angiography in Canada would lead to greater selectivity and higher diagnostic yield. It did not. The two-and-a-half-fold higher rates of angiography in the U.S. resulted in a two and a half-fold difference in the number of patients identified with severe CAD (i.e., 12 vs. 4.6 cases of severe CAD per 100 post-MI (myocardial infarction) patients in the U.S. and Canada, respectively). Using estimates from a meta-analysis of survival after coronary surgery versus medical therapy (2), Batchelor et al. (1) projected that the increased absolute detection rate of severe CAD could result in a marginal survival benefit of 5 per 1,000 patients at five years, assuming equivalent rates of surgical revascularization in both groups. The authors concluded that adopting more aggressive U.S. strategies could result in modest but meaningful improvements in long-term post-MI outcomes. Batchelor et al. (1) have conducted an important and innovative study. However, we have some concerns about their methods, results and conclusions.