Coronary Revascularization Without Cardiopulmonary Bypass Versus the Conventional Approach in High-Risk Patients

Background: The premise of coronary revascularization without cardiopulmonary bypass (off-pump coronary artery bypass graft [CABG]) proposes that patient morbidity and, potentially, mortality can be reduced without compromising the excellent results of conventional revascularization techniques (on-pump CABG). High-risk patients may benefit the most from off-pump CABG. The aim of this study was to compare early and mid-term clinical outcomes after off-pump CABG with on-pump CABG in a subset of high-risk patients.

Methods: Between January 1, 2000 and December 31, 2000, 513 high-risk patients with a Parsonnet’s risk scores of 20 or higher underwent CABG; 38.6% (n = 198) underwent on-pump CABG, and 61.4% (n = 315) had off-pump CABG. Logistic regression was used to calculate the probability of being selected for on-pump CABG given a set of preoperative risk factors. Propensity scores or the probability of being selected for on-pump CABG were computed. Relative risks, heterogeneity among strata, and interactions between surgery type and the propensity score were assessed by a multivariate Cox proportional-hazards regression for the outcomes mortality and major adverse cardiac events (death, acute myocardial infarction, stroke, reoperative CABG, percutaneous coronary intervention).

Results: Operative mortality was lower after off-pump versus on-pump CABG between the two groups after controlling for preoperative risk factors using the propensity score (odds ratio = 2.10; 95% confidence intervals = 1.02 to 4.36, p = 0.04). In the Cox-regression analysis, off-pump CABG was associated with an improved survival rate compared with on-pump CABG (p = 0.03). Off-pump CABG was associated with a comparable event-free survival (p = 0.14) compared with on-pump CABG.

Conclusions: Off-pump CABG can be performed with a reasonably low morbidity and lower early and late mortality in high-risk patients. Off-pump CABG may be a better operative strategy in this subset of patients.