Optimal timing of revascularization: transmural versus nontransmural acute myocardial infarction

Abstract

Background. Higher mortality for emergency coronary artery bypass grafting (CABG) after an acute myocardial infarction (AMI) is well established. Whether it applies to both transmural and nontransmural AMI is unclear. This information may have different therapeutic implications for each cohort of patients. Methods. A retrospective multicenter analysis of 44,365 patients who underwent CABG after myocardial infarction between 1993 and 1996 by 179 surgeons at 32 hospitals in New York State was performed. Results. Overall hospital mortality for all patients with or without AMI was 2.5% versus 3.1% for patients who underwent CABG with history of myocardial infarction. Hospital mortality decreased with increasing time interval between CABG and AMI; 11.8%, 9.5%, and 2.8% ( p < 0.001 for all values) for less than 6 hours, 6 hours to 1 day, and greater than 1 day, respectively. Patients with transmural and nontransmural AMI had identical mortality of 3.1%. However, different patterns emerged when comparing these two groups of patients with respect to time of operation. Mortality was higher in the transmural group if CABG was performed within 7 days after AMI. Multivariate analysis confirmed that CABG within 1 day and 6 hours of AMI are independent risk factors for mortality in the transmural and nontransmural groups, respectively. Conclusions. Early operation after transmural AMI has a significantly higher risk, and surgeons should be prepared to provide aggressive cardiac support including left ventricular assist devices in this ailing population. Waiting in some may be warranted.