Impact of avoiding cardiopulmonary bypass for coronary surgery on perioperative cardiac enzyme release and survival

Objective: This study examines the association between avoiding the use of cardiopulmonary bypass (CPB) for coronary surgery and postoperative cardiac enzyme (CE) release, and its subsequent impact on survival. Methods: Between January 1999 and September 2002, 3734 consecutive patients underwent either off-pump or on-pump coronary surgery. Patient characteristics and postoperative cardiac enzyme release were collected prospectively. Logistic regression was used to assess the effect of off-pump coronary surgery on cardiac enzyme release. All analyses were adjusted for preoperative characteristics and number of grafts. All patients were followed up at 1 year to assess survival. Results: Nine hundred and sixty (25.7%) patients had off-pump coronary surgery. Seven hundred and twenty-six (19.4%) patients had cardiac enzyme release three to six times the upper limit of the reference range, while 266 (7.1%) patients had cardiac enzyme release more than six times the upper limit of the reference range. After adjusting for patient characteristics, off-pump surgery was associated with less release (cardiac enzyme release three to six times, adjusted odds ratio 0.43, p ≪ 0.001; cardiac enzyme release more than six times, adjusted odds ratio 0.59, p = 0.005). Risk adjusted survival at 1 year was 97.5% for the on-pump group and 97.0% for the off-pump group (p = 0.33). Conclusions: Avoiding cardiopulmonary bypass significantly reduces early cardiac enzyme release following coronary artery bypass grafting (CABG). However, it does not result in improved survival compared to coronary surgery using cardiopulmonary bypass. This absence of survival benefit may be due to higher mortality rates experienced by the fewer patients with high (≫6 times the upper limit of range) cardiac enzyme release following coronary artery bypass surgery without cardiopulmonary bypass.