Morbidity but not mortality is decreased after off-pump coronary artery bypass surgery

Off-pump coronary bypass surgery (CABG) has been advocated to avoid the physiologic perturbations related to cardiopulmonary bypass and improve outcomes compared with on-pump CABG. Previous reports have been inconsistent, and thus its benefits remain uncertain. This retrospective study compared outcomes between on-pump and off-pump CABG from a large multicenter cohort of propensity-matched patients.

The study consisted of 21,640 patients (19,639 [90.8%] on-pump, 2,001 [9.2%] off-pump) who underwent isolated CABG between January 1, 2008, and June 30, 2011, and were entered into a statewide collaborative database. Univariate analysis compared 37 baseline characteristics between on-pump and off-pump procedures. Patients were matched 1:1 based on similarities in propensity scores derived from statistically significant baseline characteristics. Propensity scores and surgery type were used in conditional logistic regression models for predicting each of 14 postoperative outcomes using the sample of 3,898 matched procedures.

Patients undergoing off-pump CABG had significantly fewer complications overall, including decreased red blood cell transfusion, stroke, intensive care unit and ventilator time, reoperation for bleeding, and length of stay. There was no difference in renal failure, wound infection, discharge location, or 30-day readmission rate. Although off-pump patients received fewer bypass grafts per patient (2.5 ± 1.2 versus 3.0 ± 1.1; p < 0.001), operative mortality was similar for the two groups (1.8% on-pump versus 2.3% off-pump; p = 0.30).

Off-pump CABG was associated with less morbidity, shorter length of stay, and similar mortality compared with on-pump procedures, suggesting that it can be a safe and effective alternative to standard on-pump CABG. However, the limited use of off-pump CABG in this multicenter analysis may restrict the generalizability of these results, and realistically defines the limited degree of acceptance of this technique in a real-world environment.