Background: Off-pump coronary artery bypass (OPCAB) surgery has been shown to potentially decrease perioperative morbidity of coronary revascularization. Perioperative myocardial infarction (PMI) is associated with an increased perioperative morbidity and mortality. Impact of PMI on longterm mortality and cardiac-related adverse events in OPCAB patients has not been extensively studied.
Aims of the study: To evaluate how PMI impacted on long-term survival of a cohort of patients having undergone coronary revascularization.
Methods: We used our database of 1000 consecutive prospectively followed OPCAB patients operated systematically between September 1996 and March 2004 representing 96% of all coronary revascularizations during the same time frame. Follow-up was complete in 96% of the cohort. Average follow-up was 44±26 months.
Results: Average age was 64±10 years, triple vessel disease was present in 73%, unstable angina in 69% emergency surgery in 5.3%. On average 3.2 grafts/patient were performed. Operative 30-day mortality was 1.1 %. Overall survival at 8 years was 73±3.5% and cardiac survival was 94±1.3%. Perioperative non-Q MI (NQMI) occurred in 1.3%, transmural MI (QMI) in 2.0%, and evolving MI (EMI) in 1.8%. Operative mortality was higher (p<0.05) for all perioperative MI patients. Survivors of EM1 (p<0.0001) and QMI (p=0.04) had a lower life expectancy than those who did not suffer perioperative MI. By Cox regression analysis only EMI (HR: 3.7; 95% CI: 1.5-8.7) remained a significant long-term risk factor after normalization for age, sex, diabetes, hypertension, cardiac insufficiency, peripheral vascular disease, left main stenosis, redo procedure, preoperative functional class and left ventricular ejection fi-action. CKMB (24 hours) was also a strong predictor of long-term cardiac mortality even after normalization (HR: 5.6; 95% CI: 2.4-13.3), a CKMB count >25 μg/L being the significant cut-off point.
Conclusion: PMI is a strong predictor of operative mortality. EMI and CKMB >25 μg/L are also predictors of long-term overall and cardiac mortality respectively.