Timing of coronary artery bypass surgery in patients with non-ST-segment elevation myocardial infarction and postoperative outcomes

Abstract

Introduction: The aim of the study was to assess whether a cardiac troponin T (cTnT) level 1 ng/ml or below threshold is safe and to evaluate mid-term follow-up results in stable patients with non-ST-segment elevation after acute myocardial infarction. Material and methods: Among cTnT positive patients who presented to the emergency unit with chest pain and received coronary angiography, 100 patients who underwent isolated coronary artery bypass grafting (CABG) constituted the study group (group 1). The same number of patients (n = 100) who were cTnT negative and underwent an isolated CABG operation under elective conditions were selected as the control group (group 2). Results: Among preoperative criteria, group 1 had significantly higher smoking rates (74% vs. 41%, p = 0.0001), and significantly lower ejection fraction values (47.1 +/- 8.25, 54.69 +/- 8.73, p = 0.0001). There were no significant differences between the groups with respect to operative parameters. Postoperative follow-up periods were significantly longer in group 1 (23.25 +/- 14 vs. 17.55 +/- 7.95 months, p = 0.001). Average waiting time for cTnT to drop below the 1 ng/ml threshold value was 5.73 +/- 2.95 (1-12) days. Intra-aortic balloon pump use in Groups 1 and 2 was 3% and 1%, respectively. There were no hospital mortalities in either group. Mortality rates at mid term were 6% in both groups. Conclusions: This study compared two groups positive and negative for preoperative cTnT. The findings show that it is safe to wait until cTnT levels decrease to the 1 ng/ml threshold value in cTnT positive patients having a stable course. This waiting period is not very long, which is significant with respect to potential complications.