Comparing the U.S. and Canadian approaches to coronary angiography: what have we learned?

Coronary angiography after myocardial infarction is one of the most well-studied procedures in contemporary medical care (1), yet substantial geographic variability persists in the use of this procedure both within the U.S. (2,3) and between the U.S. and Canada (4–6). In this issue of the Journal, Batchelor et al. (7) described the effect of this variability on the detection of severe coronary artery disease (CAD), and they attempted to assess its implications for patients’ outcomes (7). Using data from the Global Use of Strategies to Open Occluded Arteries in Acute Coronary Syndromes (GUSTO-1) trial, Batchelor et al. (7) compared the frequency with which patients with severe (left-main or threevessel) CAD were detected in the U.S. and Canada. On the basis of earlier randomized clinical trials, these patients were