Randomized On/Off Bypass trial (ROOBY)

Anthony A. Bavry, M.D., M.P.H., F.A.C.C.; Deepak L. Bhatt, M.D., F.A.C.C.



Description: The goal of the trial was to evaluate coronary artery revascularization with off-pump compared with on-pump coronary artery bypass grafting (CABG).

Hypothesis: Off-pump CABG would be associated with similar outcomes as on-pump procedures.

Drugs/Procedures Used: Patients scheduled for elective or urgent CABG were randomized to off-pump (n = 1,104) versus on-pump (n = 1,099) procedures.

Principal Findings

Overall, 2,203 patients were randomized. There was no difference in baseline characteristics between the groups. In the off-pump group, the mean age was 63 years, 0.6% were women, 84% were Caucasian, 0.8% had previous CABG, 16% had peripheral arterial disease, 59% had an ejection fraction >54%, 33% were current smokers, and the estimated risk of death before discharge or 30 days was 1.9%.

The off-pump group received 2.9 grafts per patient, while the on-pump group received 3.0 grafts per patient (p = 0.002). Transfusion was needed in 52% versus 56% (p = 0.05), hours in the operating room were 4.5 versus 4.4 (p = 0.05), and length of stay in the hospital was 8.2 days versus 7.8 days (p = 0.22), respectively for off-pump versus on-pump.

The primary short-term composite outcome occurred in 7.0% of the off-pump versus 5.6% of the on-pump group (p = 0.19), while the primary long-term composite outcome occurred in 9.9% versus 7.4% (p = 0.04), respectively. Death within 30 days was 1.6% versus 1.2% (p = 0.47), all-cause death within 1 year was 4.1% versus 2.9% (p = 0.15), and cardiac death within 1 year was 2.7% versus 1.3% (p = 0.03), respectively for off-pump versus on-pump. Neuropsychological outcomes were similar between the groups.

Overall graft patency was 82.6% versus 87.8% (p < 0.001), saphenous vein graft patency was 76.6% versus 83.8% (p < 0.001), and at least one occluded graft was 36.5% versus 28.7% (p = 0.002), respectively for off-pump versus on-pump.


Among patients undergoing elective or urgent CABG, the use of off-pump procedures does not result in similar clinical outcomes as on-pump procedures. Off-pump CABG was associated with worse outcomes, including higher cardiac death and lower graft patency at 1 year. Off-pump patients also received slightly fewer grafts (2.9 vs. 3.0). Outcomes were the same when analyzed according to high-volume or low-volume surgeons. Cognitive function appeared to be similar in both groups. It is possible that worse long-term clinical outcomes with off-pump procedures may be due to a lower rate of graft patency.

This study does not provide any insight into the preferred surgical approach in women, so further study is needed.


  • Coronary heart disease

  • Coronary heart disease / Angina pectoris

  • Coronary heart disease / Angina pectoris / Stable


  • CABG

Study Design

Randomized. Parallel.

Patients Screened: 9,663

Patients Enrolled: 2,203

Mean Follow-Up: 1 year

Mean Patient Age: 63 years

% Female: < 1

Mean Ejection Fraction: 58% of participants had an ejection fraction > 54%

Primary Endpoints

Primary short-term outcome within 30 days: composite of death or major complications (reoperation, new mechanical support, cardiac arrest, coma, stroke, or renal failure requiring dialysis)

Primary long-term outcome within 1 year: composite of death, nonfatal myocardial infarction, or repeat revascularization

Secondary Endpoints

Completeness of revascularization

Graft patency at 1 year

Neuropsychological testing

Patient Population

Patients undergoing elective or urgent CABG


Significant valve disease

Need for immediate surgery

Small target vessels

Diffuse coronary artery disease

Patients with high-risk for adverse events

Inability of the patient to provide informed consent

Patient Population

Patients undergoing elective or urgent CABG


Comments on Medscape are moderated and should be professional in tone and on topic. You must declare any conflicts of interest related to your comments and responses. Please see our Commenting Guide for further information. We reserve the right to remove posts at our sole discretion.