Use of Cardiopulmonary Bypass in High-Risk Patients Is a Predictor of Adverse Outcome

High-risk patients experience substantially more compli cations after coronary artery bypass grafting (CABG). We hypothesized that these patients are uniquely vulner able to cardiopulmonary bypass and compared postop erative outcomes between high-risk patients undergo ing off-pump CAB (OPCAB) and conventional CABG. Prospective provincial cardiac care registry and retro spective chart data were reviewed for 1,850 consecutive patients at our institution between January 1996 and January 1999. From this, 235 patients, 36 OPCAB and 199 CABG, were identified as high risk (modified Parson net score ≥15). Risk factor analysis showed the popula tions were equivalent in perioperative risk with mean modified Parsonnet scores of 18.1 ± 3.4 (OPCAB) and 18.7 ± 4.2 (CABG) (P = .4). In total, 6% of OPCAB and 40% of CABG patients suffered major complications leading to extended hospital/intensive care unit (ICU) stay or death ( P ≤ .001). Mean hospital stays were 7.0 ± 4.0 days (OPCAB) and 10.6 ± 10.2 days (CABG) ( P ≤ .001). Mean ICU stays were 23.9 ± 9.7 hours (OPCAB) and 64.9 ± 128.3 hours (CABG) ( P ≤ .001). Mortality was 0% in the OPCAB group and 6% in the CABG group (P = .2). Multivariate predictors of experiencing a major complication were: use of cardiopulmonary bypass (OR 5.1, 95 Cl 2.1-12.1), age > 80 (OR 2.5, 95 Cl 1.7-7.5), female (OR 3.0, 95 Cl 1.6-5.4), repeat operation (OR 2.5, 95 Cl 1.2-5.4), and ejection fraction <40% (OR 2.4, 95 Cl 1.2-4.7). Extracorporeal circulation is the most impor tant predictor of postoperative complications after CABG in high-risk patients. Off-pump surgery substantially reduces morbidity in this group, and further study of the protective effects of this emerging modality are war ranted.