1. Division of General Internal Medicine; McGill University Health Center; Montreal QC Canada
2. Population Health Research Institute's Perioperative Medicine and Surgical Research Unit; Hamilton ON Canada
3. Department of Anesthesia; University of Toronto; Toronto ON Canada
4. Departments of Clinical Epidemiology and Biostatistics and Medicine; McMaster University; Hamilton ON Canada
5. Cardiology Department; Hospital de la Santa Creu i Sant Pau; Universidad Autónoma de Barcelona; Barcelona Spain
6. Iberoamerican Cochrane Center; Biomedical Research Institute (CIBERESP-IIB-Sant Pau); Barcelona Spain