Myocardial Infarction Classification on Outcomes in Nonemergent Coronary Artery Bypass Grafting

Background: Although patients with ST elevation myocardial infarctions (STEMIs) are known to have worse outcomes than patients with non-ST elevation myocardial infarctions (NSTEMIs), such differences are not well described in the subset of patients undergoing coronary artery bypass grafting. The purpose of this study is to compare postoperative outcomes of patients undergoing nonemergent coronary artery bypass grafting within 1 week after an STEMI versus NSTEMI.

Methods: A retrospective study was performed on patients undergoing isolated coronary artery bypass grafting between 1 and 7 days from an MI from 2008 to 2012. Postoperative outcomes, including mortality and composite postoperative morbidity for patients with STEMI versus NSTEMI, were compared within each group.

Results: Of the 446 patients undergoing nonemergent isolated coronary artery bypass grafting between 1 and 7 days after an MI, 122 patients (27.3%) had an STEMI. The STEMI cohort was younger with less incidence of hypertension than the NSTEMI cohort. However, aside from having a lower incidence of congestive heart failure, STEMI patients had an overall poorer cardiac status than NSTEMI patients. No differences were found in mortality, rates of major complication, length of intensive care unit stay, and length of hospital stay between STEMI and NSTEMI patients.

Conclusion: Despite differences in preoperative characteristics and pathophysiology of patients undergoing coronary artery bypass grafting between 1 and 7 days after NSTEMI versus STEMI, no difference was found in early surgical outcome. The classification of MI should therefore not influence surgical decision making in such patients.