On or off pump coronary bypass? Insight from matched and principal component analyses of 8779 operations

The aim of this paper was to compare the clinical impact of the different myocardial protection strategies in coronary artery bypass grafting (CABG) patients to facilitate decision-making for use of on- or off-pump technique.

Prospectively collected data for primary CABG patients between April 1, 1996 and December 30, 2010 (N.=8779) were analyzed. Early adverse cardiac and cerebrovascular events (ACCE) and late survival were compared between on-pump; cardioplegia (CPA, N.=3862, 44%), cross-clamp fibrillation (XCF, N.=3751, 43%), and off-pump (N.=1166, 13%) myocardial protection. Second, clinical profiling for the risk of ACCE with each strategy was performed using principal component analysis. Finally, a 1:1 matched cohort comparison of 1055 patients was done.

There were vast differences in baseline characteristics between groups. Significantly fewer grafts per patient were constructed using off-pump. There were no remarkable differences in operative mortality and 10-year survival rates between the groups after restrictive matching. Principal component analysis identified high risk profiles; factor 1 (ejection fraction 30-50%, prior myocardial infarction, non-elective operation), and factors 4 (hypertension, hypercholesterolemia, Body Mass Index >30 kg/m2) and 5 (female, octogenarian, left main stem disease) to be strongly associated with ACCE after on-pump CABG while lower risk profiles; factors 5 and 6 (extracardiac arteriopathy, prior stroke) were associated with ACCE after off-pump CABG.

Comparatively, on-pump techniques were associated with greater risk of adverse events in "high risk" patients defined by clinical characteristics, while off-pump was associated with increased risk of adverse events in "low risk" patients.