Grant: Operating Grant

There are over fifty thousand heart surgeries conducted in Canada and over one hundred thousand coronary artery bypass graft procedures in the United States yearly, and red cell transfusion rates for these patients are the highest and most variable amongst all surgical specialties. Red cells when transfused unnecessarily are associated with an increase in adverse events as are transfusions that are not administered when required as adverse events secondary to anemia may also occur. To ensure that these patients, who are at high risk of developing anemia and of receiving transfusion, receive optimal transfusion therapy, we will conduct an international multicentre controlled trial, randomizing patients having cardiac surgery to red cell transfusion using two transfusion strategies. Patients randomized to a restrictive transfusion strategy will receive red cell transfusion if their hemoglobin is less than seventy five grams per litre during and after their operation. Patients allocated to a liberal transfusion strategy will receive red cell transfusion if their hemoglobin concentration is less than ninety five grams per litre during their operation, immediately after the operation and less than eighty five grams per litre when they are transferred to the ward. Randomization will be generated by the Applied Health Research Centre at the Li KaShing Knowledge Institute of St. Michael's Hospital, the official trials unit for the University of Toronto who co-ordinated our highly successful multicentre pilot study using the same transfusion strategies. To determine if one transfusion strategy has better outcomes than the other, our primary outcome will be a combined measure of death, and major adverse events in the three vital organs that can be affected by anemia, the kidney, heart and brain.