Background: The benefits of off-pump coronary artery bypass graft (OPCAB) compared with conventional on-pump coronary artery bypass graft (CCAB) remain controversial. Thus, it is important to investigate which patient subgroups may benefit the most from OPCAB rather than CCAB.
Methods and results: Among the patients undergoing first coronary revascularization enrolled in the CREDO-Kyoto Registry (a registry of first-time percutaneous coronary intervention and coronary artery bypass graft patients in Japan), 2468 patients undergoing coronary artery bypass graft were entered into the study (mean age, 67 ± 9 years). Predicted risk of operative mortality (PROM) of each patient was calculated by logistic EuroSCORE. Patients were divided into tertile based on their PROM. Mortality rates and the incidences of cardiovascular events were compared between CCAB and OPCAB within each PROM tertile using propensity score analysis. A total of 1377 patients received CCAB whereas 1091 received OPCAB. Adjusted 30-day mortality was not significantly different between CCAB and OPCAB patients regardless of their PROM range. However, the odds ratio of 30-day stroke in CCAB compared with OPCAB in the high-risk tertile was 8.30 (95% confidence interval, 2.25-30.7; P<0.01). Regarding long-term outcomes, hazard ratio of stroke in CCAB compared with OPCAB in the high-risk tertile was 1.80 (95% confidence interval, 1.07-3.02; P=0.03). Nevertheless, hazard ratio of overall mortality in the high-risk tertile was 1.44 (95% confidence interval, 0.98-2.11; P=0.06), indicating no statistically significant difference between the 2 procedures.
Conclusions: OPCAB as opposed to CCAB is associated with short-term and long-term benefits in stroke prevention in patients at higher risk as estimated by EuroSCORE. No survival benefit of OPCAB was shown regardless of preoperative risk level.