Six-Month Outcomes after Restrictive or Liberal Transfusion for Cardiac Surgery
C David Mazer1, Richard P Whitlock1, Dean A Fergusson1
1From the Department of Anesthesia (C.D.M., G.M.T.H., N.M.) and the Department of Surgery, Division of Cardiac Surgery (S.V.), St. Michael's Hospital, Keenan Research Centre for Biomedical Science, the Li Ka Shing Knowledge Institute of St. Michael's Hospital (C.D.M., G.M.T.H., K.T., S.V., P.J.), Applied Health Research Centre (J.H., D.D., K.T., S.V., P.J.), Sunnybrook Health Sciences Centre (S.F.), Division of Hematology, Mount Sinai Hospital (N.S.), the Departments of Medicine (P.J., N.S.), Physiology (C.D.M., G.M.T.H), and Laboratory Medicine and Pathobiology (N.S.), Dalla Lana School of Public Health (K.T.), and Institute of Health Policy, Management and Evaluation, University of Toronto, and Canadian Blood Services (N.S.), Toronto, the Population Health Research Institute (R.P.W., E.B.-C.), Hamilton Health Sciences Center (R.P.W., E.B.-C., K.C., S.S.), McMaster University (R.P.W., E.B.-C., K.C., S.S.), Hamilton, ON, the Ottawa Hospital Research Institute, University of Ottawa, Ottawa (D.A.F.), the Cumming School of Medicine and Libin Cardiovascular Institute, University of Calgary, Calgary (A.J.G.), and the Department of Critical Care Medicine, Faculty of Medicine and Dentistry, University of Alberta, Edmonton (S.M.B.), CHUS-Centre Hospitalier Universitaire de Sherbrooke, Sherbrooke (É.M.), and the Department of Anesthesiology and Critical Care Medicine, Institut Universitaire de Cardiologie et de Pneumologie de Québec, Laval University, Laval (F.L.), QC, the Departments of Anesthesia and Medicine, Division of Critical Care, Centre Hospitalier de l'Université de Montréal, Montreal (F.M.C.), and the Department of Anesthesia, Perioperative and Pain Medicine, St. Boniface Hospital, University of Manitoba, Winnipeg (H.P.G.) - all in Canada; the Department of Cardiothoracic Anesthesia, Rigshospitalet, Copenhagen University Hospital, Copenhagen (B.K.); Medical Research Institute of New Zealand, Wellington (S.M., P.J.Y.), and Waikato Hospital, Hamilton (K.B.) - both in New Zealand; Fundación Cardioinfantil-Instituto de Cardiología and Universidad Autónoma de Bucaramanga, Bucaramanga, Colombia (J.C.V.); the Department of Surgery, University of Melbourne (A.R., C.R.), and the Department of Anaesthesia and Pain Management, Royal Melbourne Hospital (C.R.), Melbourne, VIC, and the Department of Anaesthesia, Royal Adelaide Hospital, and the Discipline of Acute Care Medicine, University of Adelaide, Adelaide, SA (T.W.P.) - all in Australia; University of Basel, Department of Anesthesia, Surgical Intensive Care, Prehospital Emergency Medicine and Pain Therapy, University Hospital Basel, Basel, and Klinik Hirslanden Zurich, Zurich - both in Switzerland (M.D.S.); Heart Care Associates, SAL Hospital, Gujarat, India (C.M.); and the Department of Cardiothoracic Anaesthesia, National Heart Center, and the Department of Anaesthesiology, Singapore General Hospital - both in Singapore (N.-C.H.).
Background:
We reported previously that, in patients undergoing cardiac surgery who were at moderate-to-high risk for death, a restrictive transfusion strategy was noninferior to a liberal strategy with respect to the composite outcome of death from any cause, myocardial infarction, stroke, or new-onset renal failure with dialysis by hospital discharge or 28 days after surgery, whichever came first. We now report the clinical outcomes at 6 months after surgery.
Methods:
We randomly assigned 5243 adults undergoing cardiac surgery to a restrictive red-cell transfusion strategy (transfusion if the hemoglobin concentration was <7.5 g per deciliter intraoperatively or postoperatively) or a liberal red-cell transfusion strategy (transfusion if the hemoglobin concentration was <9.5 g per deciliter intraoperatively or postoperatively when the patient was in the intensive care unit [ICU] or was <8.5 g per deciliter when the patient was in the non-ICU ward). The primary composite outcome was death from any cause, myocardial infarction, stroke, or new-onset renal failure with dialysis occurring within 6 months after the initial surgery. An expanded secondary composite outcome included all the components of the primary outcome as well as emergency department visit, hospital readmission, or coronary revascularization occurring within 6 months after the index surgery. The secondary outcomes included the individual components of the two composite outcomes.
Results:
At 6 months after surgery, the primary composite outcome had occurred in 402 of 2317 patients (17.4%) in the restrictive-threshold group and in 402 of 2347 patients (17.1%) in the liberal-threshold group (absolute risk difference before rounding, 0.22 percentage points; 95% confidence interval [CI], -1.95 to 2.39; odds ratio, 1.02; 95% CI, 0.87 to 1.18; P=0.006 for noninferiority). Mortality was 6.2% in the restrictive-threshold group and 6.4% in the liberal-threshold group (odds ratio, 0.95; 95% CI, 0.75 to 1.21). There were no significant between-group differences in the secondary outcomes.
Conclusions:
In patients undergoing cardiac surgery who were at moderate-to-high risk for death, a restrictive strategy for red-cell transfusion was noninferior to a liberal strategy with respect to the composite outcome of death from any cause, myocardial infarction, stroke, or new-onset renal failure with dialysis at 6 months after surgery. (Funded by the Canadian Institutes of Health Research and others; TRICS III ClinicalTrials.gov number, NCT02042898 .).
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