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Summary

Background: Coronary artery disease remains a major cause of death in Canada and consumes a significant proportion of our health care budget. Coronary artery bypass graft (CABG) surgery is a well-recognized treatment of advanced coronary artery disease. The perioperative mortality is about 2% with an additional 5% to 7% suffering complications such as myocardial infarction, stroke, renal failure, and an additional 20% to 40% of patients developing neuro-cognitive dysfunction, atrial fibrillation or receiving transfusions of blood products. The technique of operating on a beating heart (off-pump) for coronary artery bypass grafting surgery has been recently developed in an effort to decrease the above perioperative complications typically related to cardiopulmonary bypass and aortic cannulation associated with on-pump CABG. While registries suggest that off-pump CABG may be superior, these data cannot fully control for differences in patient characteristics that influence patient selection for specific procedures. The lack of clear results even in a meta-analysis of all randomized trials may be related to the small number of events resulting from the inclusion of only low risk patients, the relatively small number of patients and the lack of long term follow-up. The benefits of off-pump CABG compared with conventional on-pump CABG are unclear. In view of a lack of clear clinical benefit on major outcomes with off-pump procedures and concerns that incomplete revascularization and higher graft failure rate would lead to poorer long term prognosis, there is a real need for a trial to reliably evaluate the short and long term safety and efficacy of off-pump CABG. We, therefore, propose a large simple international multicentre randomized controlled trial to definitely evaluate the efficacy and safety of off-pump CABG in the treatment of patients undergoing coronary artery surgery.

Objectives: In patients undergoing CABG surgery (1) to determine if off-pump CABG surgery compared to on-pump CABG surgery reduces major clinical vascular events at short term (30 days) and at long term (5 years) (2) to determine if off-pump CABG surgery compared to on-pump CABG surgery reduces costs in the short term (30 days) and at long term (5 years) (cost-effectiveness analysis).

Subjects and Methods: Subjects will be patients who undergo CABG surgery with median sternotomy. They will be randomized to receive the new off-pump technique (beating heart surgery) vs. the conventional on-pump CABG surgery. This trial will recruit 4700 patients from approximately 100 cardiac surgery centers in North America, South America, Europe, Asia and South Asia. The follow-up period is 5 years. The co-primary outcomes are a composite of total mortality, MI, stroke, renal failure, at 30 days and a composite of total mortality, MI, stroke, renal failure and repeat revascularization at 5 years. The secondary outcome of CORONARY is the assessment of total costs and resources consumption at 30 days and 5 year after CABG surgery with a cost-effectiveness analysis. Other outcomes of interest include neuro-cognitive dysfunction, recurrence of angina, cardiovascular mortality, blood transfusions and quality of life. The effect of the two operative techniques on different sub-groups (i.e. patients with diabetes, cerebrovascular disease, as well as patient left ventricular function, gender, age and vessels diseased will be examined for consistency and coherence. An events adjudication committee (blind to surgical allocation) will centrally review all suspected major outcomes listed above. Expertise-based randomization will be used to avoid biases associated with a more technically demanding procedure.

Inclusion criteria:
Isolated CABG cases (urgent or elective) with one of the following inclusion criteria are eligible for the study:
  1. ≥70 age OR
  2. peripheral vascular disease OR
  3. cerebrovascular disease OR
  4. renal insufficiency (creatinine >115) OR
  5. ≥60 age with one of the following:
    1. diabetes (oral hypoglycemic agent and/or insulin)
    2. urgent revascularization (waiting in hospital)
    3. LV EF <35%
    4. current smoker
Exclusion criteria:
Participants will be excluded from the study if they:
  1. are less than 21 years of age.
  2. require CABG and a concomitant procedure.
  3. have contra-indication to either off-pump or on-pump surgery.
  4. have concomitant life-threatening disease likely to limit life expectancy to less than 2 years.
  5. were previously enrolled in this trial.
  6. require emergency CABG surgery (immediate revascularization for hemodynamic instability).
  7. previously had CABG surgery.