Medium-term outcomes of coronary artery bypass graft surgery on pump versus off pump: Results from a randomized controlled trial

Background: Despite the proposed advantages of off-pump coronary artery bypass graft (CABG) surgery, some controversy remains as to its advantages compared with on-pump CABG. The present study evaluates medium-term outcomes from patients that have been randomized to CABG surgery performed on pump versus off pump. Methods: All consecutive patients enrolled into a previously completed randomized trial comparing CABG surgery performed on (n = 150) versus off (n = 150) pump were included. The analysis was performed on an intention-to-treat basis. The outcomes of interest were all-cause mortality and readmission to hospital for cardiac reason. Results: The in-hospital outcomes were excellent in both groups with a mortality rate of 0.7% in the on-pump versus 1.3% in the off-pump group (P = .56). Median follow-up was 3.8 years (interquartile range, 3.4-4.4 years) with 1 patient lost to follow-up (99% complete). There were 12 late deaths, 8 in the off-pump group and 4 in the on-pump group, which were not statistically different between groups (P = .23) and resulted in a greater than 90% survival at 4 years. Freedom from readmission to hospital for cardiac cause was not statistical different between the 2 groups with 70% event-free survival at 4 years. Multivariate analysis failed to identify the type of procedure (on vs off pump) as an independent predictor of adverse cardiovascular event (mortality + readmission to hospital). Conclusions: We have shown that in patients randomized to CABG surgery performed on pump versus off pump, excellent medium-term results can be obtained with either technique. We have been unable to demonstrate that one technique is superior to the other.