CABG: To CBP or Not To CBP - A Propensity Score Matched Survival.

Introduction: Over the past 3 decades two main strategies have been employed for surgical coronary revascularization (CABG): on- pump CABG with cardioplegia (ONCAB) and off-pump CABG (OPCAB). The objective of this study is to evaluate the short-term and long-term survival of the two strategies.

Methods: This study consists of 8-year cohort, retrospective single-center analysis with an intention-to-treat design. 2954 patients underwent CABG (OPCAB n=2123; ONCAB= 831) for CAD. As these two groups were statistically different regarding several parameters, a propensity score model was applied and a more homogeneous cohort (n= 1441; OPCAB= 885; ONCAB=556) was analyzed. Univariate analysis, Kaplan-Meier curves and when appropriate a multivariate analysis was applied to the overall group and 6 subgroups: 2 vessel disease, 3 vessel disease, left stem disease, diabetic patients; patients with creatinin clearance bellow 50ml/min; and patients with body mass index above 30 kg/m2.

Results: Our study show: No difference in 30-days mortality, long-term survival (mean 71 months follow-up), AKY and stroke rates; Higher rates of bypass per patient (2.3% vs 2.8%, p<0,001) and complete revascularization (76% vs 83%) in the ONCAB group; Fewer re-operation for bleeding (0.8 vs 3.8%, p<0.001), fewer peak troponin>19mg/ dl (4.7% vs 9.9%, p<0,001), and fewer IABP use (1.5% vs 3.3%, p=0,027) in the OPCAB group. Sub-group analysis showed no difference between the two groups with exception of a higher rate of troponin peak >19mg/dl adjusted for CAD extension in the left-main stem disease group undergoing ONCAB (OR=2,3 +-0.8 p=0,018).

Conclusion: The major randomized controlled trials comparing the two strategies show: No difference in 30-days mortality, 1-year survival, AKY and stroke rates; Less re-revascularization rates and higher bypass per patient and bypass patency with ONCAB. Despite the large volume of evidence generated around both on-pump and off-pump CABG strategies, studies fail to demonstrate clear benefit of either strategy regarding mortality and most common complications. Our results are similar of those found in the literature as neither strategy has unequivocal superior results. ONCAB shows consistently higher rates of complete revascularization and higher number of grafts. OPCAB shows lesser troponin levels suggestive of less myocardial damage. Major limitations include: analysis not matched for surgeon performance; cardiac related events, re-revascularization need and graft patency not evaluated; isolated use of troponin levels for evaluation myocardial damage.