The insulin cardioplegia trial: myocardial protection for urgent coronary artery bypass grafting.
BACKGROUND
Small, nonrandomized clinical trials have demonstrated a beneficial effect of solutions containing insulin and glucose on the recovery of myocardial metabolism and ventricular function after cardioplegic arrest and reperfusion. However, no large, blinded, randomized study has yet determined the effects of insulin-enhanced cardioplegia on clinical outcomes after coronary artery bypass grafting.


METHODS
The Insulin Cardioplegia Trial was designed to evaluate the clinical impact of insulin-enhanced cardioplegia on patients at high risk undergoing isolated coronary artery bypass grafting for unstable angina. A total of 1127 patients were randomly assigned at operation to receive cardioplegic solution supplemented with 10 IU/L insulin (n = 557) or placebo (n = 570). All personnel with direct patient contact were blinded to randomization group.


RESULTS
Overall operative mortality was 2.2%, with no significant differences between groups. The prevalences of postoperative low output syndrome (insulin 10.4%, placebo 9.7%, P =.7) and enzymatic myocardial infarction (insulin 21.0%, placebo 18.8%, P =.3) were not different between groups. The primary composite outcome of low output syndrome and/or enzymatic myocardial infarction revealed no difference between groups (insulin 30.0%, placebo 26.3%, P =.2).


CONCLUSIONS
Despite encouraging results from smaller, nonrandomized studies, the Insulin Cardioplegia Trial failed to demonstrate a clinical benefit of insulin-enhanced cardioplegic solution for patients undergoing high-risk isolated coronary artery bypass grafting.
Rao
Vivek
V
Division of Cardiovascular Surgery, Toronto General Hospital, University of Toronto, Toronto, Ontario, Canada. Vivek.Rao@uhn.on.ca
Christakis
George T
GT
Weisel
Richard D
RD
Ivanov
Joan
J
Borger
Michael A
MA
Cohen
Gideon
G
D000328:Adult; D000368:Aged; D000789:Angina, Unstable / Q000175:diagnosis / Q000601:surgery*; D002314:Cardioplegic Solutions / Q000008:administration & dosage*; D016001:Confidence Intervals; D001026:Coronary Artery Bypass / Q000379:methods; D004311:Double-Blind Method; D005260:Female; D005500:Follow-Up Studies; D006324:Heart Arrest, Induced / Q000379:methods*; D006801:Humans; D007328:Insulin / Q000008:administration & dosage*; D016015:Logistic Models; D008297:Male; D008875:Middle Aged; D009203:Myocardial Infarction / Q000517:prevention & control*; D011300:Preoperative Care; D011336:Probability; D012016:Reference Values; D016896:Treatment Outcome
D002314:Cardioplegic Solutions; D007328:Insulin