Randomized On/Off Bypass trial - ROOBY

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.

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%

Patient Populations:

  • Patients undergoing elective or urgent CABG

Exclusions:

  • 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

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

Drug/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.

Interpretation:

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.

References:

Shroyer AL, Grover FL, Hattler B, et al. On-pump versus off-pump coronary-artery bypass surgery. N Engl J Med 2009;361:1827-37.

Keywords: Cognition, Coronary Artery Disease, Angina, Stable, Saphenous Vein, Peripheral Arterial Disease, Coronary Artery Bypass, Length of Stay


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