Determinants of myocardial infarction following emergency coronary artery bypass for failed percutaneous coronary angioplasty.

Acute myocardial ischemia during percutaneous transluminal coronary angioplasty (PTCA) often necessitates emergency coronary artery bypass grafting (CABG) and can result in myocardial infarction (MI). This study was undertaken to determine what factors might predispose to MI following emergency CABG for failed PTCA. Since 1980, 24 patients at Boston University Medical Center have undergone emergency CABG following failed PTCA. In 15 patients (63%), there was postoperative evidence of an MI shown by either ECG or enzyme criteria. Variables that predisposed to a perioperative MI (p less than 0.05) included multivessel PTCA, the presence of multiple vessels with 50% stenosis or more, multivessel CABG, and the presence of new ECG changes immediately following failed PTCA. Variables that did not discriminate between the two groups included age, sex, the specific vessel involved during PTCA, or a previous history of MI. The presence of coronary collaterals did not decrease the incidence of MI. This study suggests that patients with multiple major coronary stenoses in whom acute ECG changes develop following failed PTCA are more likely to sustain a perioperative MI following emergency CABG.