Extent, Location, and Clinical Significance of Non–Infarct-Related Coronary Artery Disease Among Patients With ST-Elevation Myocardial Infarction
What is the incidence, extent, and location of obstructive non–infarct-related artery (IRA) disease in patients with ST-segment elevation myocardial infarction (STEMI), and how does that impact 30-day mortality?
The authors pooled data from a sample of eight independent, international, randomized STEMI clinical trials published between 1993 and 2007. These trials enrolled a total of 68,765 Patients, of whom 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).
Obstructive non-IRA disease was present in nearly half (52.8%, n = 14,929) of the patients. The majority of these cases were one-vessel (29.6% of all) and the rest involved two vessels. There was no clinically important difference in the extent and distribution of non-IRA disease according to the IRA territory. Unadjusted (4.3% vs. 1.7%) and adjusted rates (3.3% vs. 1.9%; risk difference, 1.4%, 95% confidence interval, 1.0%-1.8%, p < 0.001).) of 30-day mortality were significantly higher in patients with non-IRA disease than in those without non-IRA disease. 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%), but not with the Duke database (adjusted, 4.7% vs. 4.3%).
The authors concluded that obstructive non-IRA disease was common among patients presenting with STEMI, and was associated with a modest statistically significant increase in 30-day mortality.
The findings of this study will not be news to clinicians caring for patients with STEMI. Non-IRA disease is widely prevalent in patients undergoing primary percutaneous coronary intervention (PCI) (or other reperfusion strategies), and the association with slightly worse 30-day mortality is to be expected. It is, however, not clear whether this association is causal and can be altered by earlier complete revascularization. The PRAMI study (N Engl J Med 2013;369:1115-23) suggests a benefit of preventive PCI of non-IRA lesions ,but the study was underpowered to demonstrate a survival difference. Based on the totality of current evidence, significant non-IRA lesions should be revascularized early, although it is not clear if this is best done at the time of primary PCI or staged during the index hospitalization.
Keywords: Coronary Artery Disease, Myocardial Infarction, Republic of Korea, Constriction, Pathologic, Confidence Intervals, Percutaneous Coronary Intervention, AHA Annual Scientific Sessions
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