Extent, Location, and Clinical Significance ? of Non-Infarct-Related Coronary Artery Disease Among Patimts With ST-Elevation Myocardial Infarction

IMPORTANCE Little information exists about the anatomical characteristics and clinical relevance of non-infarct-related artery (IRA) disease among patients with ST-segment elevation myocardial infarction (STEM1). OBJECTIVES To investigate the incidence, extent, and location of obstructive non-IRA disease and compare 30-day mortality according to the presence of non-IRA disease in patients with STEMI. DESIGN, SETTING, AND PARTICIPANTS Retrospective study of patients pooled from a convenience sample of 8 independent, international, randomized STEMI clinical trials published between 1993 and 2007. Follow-up varied from 1 month to 1year. Among 68 765 patients enrolled in the trials, 28 282 patients with valid angiographic information were included in this analysis. Obstructive coronary artery disease was defined as stenosis of 50% or more of the diameter of a major epicardial artery. To assess the generalizability of trial-based results, external validation was performed using observational data for patients with STEMI from the Korea Acute Myocardial Infarction Registry (KAMIR) (between November 1, 2005, and December 31, 2013; n = 18 217) and the Duke Cardiovascular Databank (between January 1, 2005, and December 31, 2012; n = 1812). MAIN OUTCOMES AND MEASURES Thirty-day mortality following STEMI. RESULTS Overall, 52.8% (14 929 patients) had obstructive non-IRA disease; 29.6% involved 1 vessel and 18.8% involved 2 vessels. There was no substantial difference in the extent and distribution of non-IRA disease according to the IRA territory. Unadjusted and adjusted rates of 30-day mortality were significantly higher in patients with non-IRA disease than in those without non-IRA disease (unadjusted, 4.3% vs 1.7%, respectively; risk difference, 2.7% [95% Cl, 2.3% to 3.0%], P < .001; and adjusted, 3.3% vs 1.9%, respectively; risk difference, 1.4% [95% Cl, 1.0% to 1.8%], P < .001). The overall prevalence and association of non-IRA disease with 30-day mortality was consistent with findings from the KAMIR registry (adjusted, 3.6% for patients with non-IRA disease vs 2.5% in those without it; risk difference, 1.1% [95% Cl, 0.6% to 1.7%]; P < .001), but not with the Duke database (adjusted, 4.7% with non-IRA disease vs 4.3% without it; risk difference, 0.4% [95% Cl, -1.4% to 2.2%], P =.65). CONCLUSIONS AND RELEVANCE In a retrospective pooled analysis of 8 clinical trials, obstructive non-IRA disease was common among patients presenting with STEMI, and was associated with a modest statistically significant increase in 30-day mortality. These findings require confirmation in prospectively designed studies, but raise questions about the appropriateness and timing of non-IRA revascularization in patients with STEMI.