Off-pump bypass surgery and postoperative stroke: California coronary bypass outcomes reporting program

Background: Coronary artery bypass surgery (CABG) is associated with a significant risk of stroke. Some studies suggest that off-pump CABG (OPCAB) may reduce postoperative stroke rate. We performed this study to evaluate the relationship between postoperative stroke and OPCAB compared with conventional on-pump CABG (CCB) in a recent, large cohort of patients. Methods: Data from the California CABG Outcomes Reporting Program were analyzed in patients who had OPCAB or CCB for isolated CABGs in 2006 to 2007. Two multivariable logistic regression models were developed for the analysis, and the "recycled predictions" method was used to compute risk-adjusted postoperative stroke rates in the two surgical groups. Results: Of 30,426 isolated CABGs, 7,720 (23.7%) were OPCAB. The model developed in the CCB subset indicated that CCB had a lower predicted stroke risk than OPCAB, yet the observed rate of stroke was higher in the CCB subset. The model using both CCB and OPCAB patients revealed that OPCAB was associated with a reduction in postoperative stroke (adjusted odds ratio: 0.76, 95% confidence interval [CI] 0.59 to 0.98). For patients with cardiogenic shock, OPCAB was also associated with a lower risk-adjusted postoperative stroke rate compared with CCB (OPCAB: 3.06%, 95% CI 2.83% to 3.28%; CCB: 4.05%, 95% CI 3.76% to 4.33%, p < 0.001). However, the 793 (11%) OPCAB patients who were converted to CCB intraoperatively had an increased postoperative stroke rate (with conversion: 2.02%, 95% CI 1.04% to 3.00% versus without conversion: 0.96%, 95% CI 0.73% to 1.20%, p < 0.001). Conclusions: The OPCAB was associated with a significantly lower postoperative stroke rate compared with CCB even for older and higher risk patients. However, intraoperative OPCAB to CCB conversion was associated with the highest postoperative stroke rate.