Fig. 1.
Flow diagram illustrating selection of patients included in the analytic cohort. “High-risk surgery” and “intermediate- or low-risk surgery” refers to risk of surgery, and does not take into account patient risk. Procedures were classified as high-risk or low/intermediate-risk surgeries based on the approach used in the derivation of the Revised Cardiac Risk Index and the procedure stratification described in the American College of Cardiology/American Heart Association 2007 guidelines. ACS = American College of Surgeons; ASA PS = American Society of Anesthesiologists physical status; MI = myocardial infarction.