Evolution of Off-Pump Coronary Artery Bypass Grafting over 15 Years

Abstract

Background Off-pump coronary artery bypass grafting for multivessel disease is an important alternative to conventional myocardial revascularization using cardiopulmonary bypass. The development of exposure and stabilization techniques has made this surgery simple, safe, and routine. Experience with the technique, its evolution, the learning curve, and the pitfalls is presented. Methods A retrospective analysis was made of 28,216 patients who underwent elective coronary artery bypass grafting over a 15-year period from January 1990 through December 2004. Isolated off-pump coronary artery bypass grafting was performed in 14,030 patients and on-pump coronary artery bypass grafting in 14,186 patients. The overall period was divided into 3 groups of 5 years each: group I (1990–1994), group II (1995–1999), and group III (2000–2004). Initially, off-pump coronary artery bypass grafting was performed selectively in high-risk patients (eg, atheromatous aorta, severe systemic impairment, chronic obstructive pulmonary disease, octogenarian). Recently (2000–2004), multivessel off-pump coronary artery bypass grafting has been performed electively in 96% to 98% of patients undergoing coronary artery bypass grafting. Patients’ medical charts were reviewed for age, preoperative risk factors, operative findings, intraoperative conversion rate to cardiopulmonary bypass, postoperative complications, and length of hospital stay. Results In the years 1990–1994 (group I), mostly high-risk cases and cases with left anterior descending coronary artery lesions were included for off-pump coronary artery surgery. In the years 1995–1999 (group II), patients with double and triple vessel disease presenting for coronary artery bypass surgery were accepted for off-pump surgery irrespective of preoperative risk factors. However, in the years 2000–2004 (group III), off-pump coronary artery bypass surgery was the first choice of approach for any patient presenting for coronary artery bypass surgery. The mean number of grafts was lower in off-pump cases than in on-pump cases in group I (2.0 ± 0.4 vs. 3.2 ± 0.80) and group II (2.6 ± 0.6 vs. 3.3 ± 0.4), whereas the mean number of grafts was higher in off-pump cases than in on-pump cases in group III (3.5 ± 0.2 vs. 3.4 ± 0.8). In groups I and II, the conversion to cardiopulmonary bypass was 5.2% and 5.9%, respectively. The conversion to cardiopulmonary bypass decreased to 1.7% in group III, which was statistically significant. Perioperative myocardial infarction was 5.2% in group I, 1.7% in group II, and 1.5% in group III. The difference between groups II and III was not statistically significant. Hospital mortality was higher in group I (5.2%) than in group II (1.2%) or III (1.1%). The difference between groups II and III was not statistically significant. Length of intensive care unit stay was 36 ± 8 hours in group I, 28 ± 7 hours in group II, and 20 ± 8 hours in group III. These differences were statistically significant. Length of postoperative hospital stay was 8 ± 2 days in group I, 7 ± 2 days in group II, and 5 ± 2 days in group III These differences were statistically significant. Conclusions As surgeons’ experience matures, off-pump coronary artery bypass surgery permits total myocardial revascularization in virtually all patients with multivessel coronary artery disease. Despite a significant learning curve, evolution to routine off-pump coronary artery bypass with good patient outcomes can be achieved with careful patient selection during the “learning curve.” The method is safe and reproducible, and patients benefit with shorter intensive care unit and hospital stays.