Prospective Randomized Comparison of Off-Pump and On-Pump Multi-vessel Coronary Artery Bypass Surgery - PROMISS

Jul 06, 2010
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Author/Summarized by Author:
Anthony A. Bavry, MD, MPH, FACC
Summary Reviewer:
Deepak L. Bhatt, MD, MPH, MBA, FACC
Trial Sponsor:
Merck Foundation, and Sociedade de Gestão Hospitalar Cruz Vermelha Portuguesa SA
Date Published:
01/01/2010
Date Updated:
07/06/2010
Original Posted Date:
07/06/2010
References

Description:

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

Hypothesis:

Off-pump CABG would result in similar graft patency.

Study Design

  • Randomized
  • Blinded
  • Parallel

Patient Populations:

  • Screened applicants: 196
  • Enrollees: 150
  • Duration of follow-up: mean 498 days
  • Age range: mean 66 years
  • Percentage female: 18%
  • Ejection fraction: 93% with LVEF ≥50%
  • Patients between the ages of 30 and 90 years with multi-vessel coronary artery disease undergoing CABG with at least three distal coronary anastomoses

Exclusions:

  • Patients requiring inotropes
  • Use of intra-aortic balloon pump
  • Intubation
  • Serum creatinine >1.5 x the upper limit of normal
  • Atrial fibrillation
  • Allergy to contrast dye
  • Premenopausal women
  • Inability to provide informed consent

Primary Endpoints:

  • Coronary artery bypass graft patency at 5 weeks

Secondary Endpoints:

  • Clinical outcomes at 30 days and 1 year

Drug/Procedures Used:

Patients undergoing CABG were randomized to off-pump (n = 75) versus on-pump (n = 75) surgery.

Concomitant Medications:

Patients in the off-pump group received heparin 200 U/kg to achieve an activated clotting time >250 seconds, whereas patients in the on-pump group received heparin 300 U/kg to achieve an activated clotting time >400 seconds.

At the conclusion of surgery, patients in both groups were reversed with 1.3 mg/100 U protamine.

Principal Findings:

There was no difference in baseline characteristics between the groups. Among off-pump patients, the mean age was 66 years, 18% were women, 18% had a body mass index ≥30 kg/m2, 36% had diabetes, 49% had previous myocardial infarction, and 67% had an acute coronary syndrome.

One patient crossed over from off-pump to on-pump, whereas two patients crossed over from on-pump to off-pump due to porcelain aorta. The mean dose of heparin was 15,000 U in the off-pump group and 23,000 U in the on-pump group (p < 0.001). The mean number of grafts performed per patient was 3.5 in both groups. All patients received a left internal mammary artery graft and 37% versus 41%, respectively, received bilateral mammary artery grafts.

The primary outcome, graft patency (by computed tomography angiography) at 5 weeks was 90% in the off-pump group versus 95% in the on-pump group (p = 0.03). There was no significant interaction based on type of graft or the grafted vessel. After controlling for dose of intraoperative heparin, the difference was no longer significant (p = 0.83).

At 30 days, there were no deaths or strokes in either group. Transient ischemic attacks occurred in zero versus two patients, for the off-pump versus on-pump groups. At a mean of 498 days, there were one versus three deaths, respectively.

Interpretation:

Among patients with multi-vessel coronary artery disease undergoing CABG, the use of the off-pump technique resulted in lower graft patency at 5 weeks. Both groups received the same number of grafts per patient, although the off-pump group received less total intraoperative heparin. When the dose of heparin was accounted for, there was no longer a difference in graft patency between the groups. Short- and long-term clinical outcomes appeared to be similar between the groups.

An accumulating body of evidence is revealing that while off-pump CABG is feasible, graft patency appears to be slightly compromised with this technique. In addition to inferior graft patency, the much larger ROOBY trial also revealed worse clinical outcomes including cardiac death with off-pump CABG. This surgical technique might be a reasonable option for patients with a severely calcified aorta, and it remains understudied in women.

References:

Uva MS, Cavaco S, Oliveira AG, et al. Early graft patency after off-pump and on-pump coronary bypass surgery: a prospective randomized study. Eur Heart J 2010;Jul 1:[Epub ahead of print].

Keywords: Coronary Artery Disease, Stroke, Acute Coronary Syndrome, Myocardial Infarction, Ischemic Attack, Transient, Dental Porcelain, Follow-Up Studies, Angina, Stable, Heparin, Body Mass Index, Tomography, Mammary Arteries, Coronary Artery Bypass, Diabetes Mellitus


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