Best Bypass Surgery trial - BBS
The goal of the trial was to evaluate coronary artery bypass graft surgery (CABG) performed off-pump versus on-pump in patients with coronary artery disease.
Off-pump CABG would be associated with improved adverse outcomes in high-risk patients.
Patients Screened: 2,578
Patients Enrolled: 341
NYHA Class: NYHA class III or IV: 29%
Mean Follow Up: 30 days
Mean Patient Age: 76 years
Mean Ejection Fraction: 51% with ejection fraction >50%
- Patients at least 54 years of age with EuroSCORE ≥5 and three-vessel coronary disease involving a marginal artery
- Elective or subacute indication for surgery
- Previous heart surgery
- Left ventricular ejection fraction
- Inability to provide informed consent
- Unstable preoperative condition
- Composite of all-cause mortality, acute myocardial infarction, resuscitated cardiac arrest, low cardiac output/cardiogenic shock, stroke, or coronary re-intervention at 30 days
- Hyperdynamic shock
- New-onset atrial fibrillation
- Need for pacing more than 24 hours
- Renal failure
- Respiratory failure requiring re-intubation
- Length of stay in the intensive care unit and the hospital
High-risk patients (EuroSCORE ≥5) with three-vessel coronary disease were randomized to off-pump CABG (n = 177) versus on-pump CABG (n = 164).
Patients in the off-pump group were given 100 U/kg of unfractionated heparin to achieve an activated clotting time >200 seconds. Patients in the on-pump group were given 300 U/kg to achieve an activated clotting time >480 seconds, which was reversed with protamine sulfate at the end of the procedure.
Overall, 341 patients were randomized. There was no difference in baseline characteristics between the groups. In the off-pump arm, the mean age was 76 years, 35% were women, body mass index was 26.3 kg/m2, 18% had diabetes, 11% had chronic obstructive pulmonary disease, 21% were current smokers, 51% had an ejection fraction >50%, and the mean EuroSCORE was 6.9. The predicted 30-day mortality was approximately 3%.
In the off-pump group, 4.5% of patients crossed over to on-pump CABG (mainly due to hemodynamic instability). In the on-pump group, 3.7% of patients crossed over to off-pump CABG (mainly due to severe aortic calcification). The mean number of grafts per patient was 3.22 in the off-pump group versus 3.34 in the on-pump group (p = 0.11), whereas the mean number of grafts to the lateral wall of the heart was 0.97 versus 1.14 (p = 0.01), respectively.
The 30-day composite primary outcome occurred in 15% of the off-pump group versus 18% of the on-pump group (p = 0.47). Death was 3.4% versus 6.7%, myocardial infarction was 5.1% versus 9.2%, stroke was 4.0% versus 3.7%, coronary re-intervention was 0.6% versus 1.8%, new-onset atrial fibrillation was 43% versus 44%, re-operation for bleeding was 5.1% versus 2.4%, and hemodialysis was 4.0% versus 4.9%, respectively for off-pump versus on-pump (p = NS, for all comparisons).
Among patients with three-vessel coronary artery disease and elevated clinical risk, the use of off-pump CABG is feasible. This method of revascularization is associated with similar short-term adverse events compared with on-pump CABG. While the mean number of grafts was similar between the groups, fewer grafts were placed to the lateral wall of the heart with off-pump CABG. This might affect long-term outcomes, which were shown to be worse with off-pump CABG in the larger ROOBY trial. The current trial was conducted at a single center and only reported outcomes to 30 days.
Moller CH, Perko MJ, Lund JT, et al. No major differences in 30-day outcomes in high-risk patients randomized to off-pump versus on-pump coronary bypass surgery. The Best Bypass Surgery Trial. Circulation 2010;121:498-504.
Clinical Topics: Cardiac Surgery, Invasive Cardiovascular Angiography and Intervention
Keywords: Renal Dialysis, Pulmonary Disease, Chronic Obstructive, Myocardial Infarction, Stroke, Body Mass Index, Cardiopulmonary Bypass, Coronary Artery Bypass, Hemodynamics, Diabetes Mellitus
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