Figure 27-13a Coronary risk assessment. Risk stratification strategies for determining a patient's candidacy for preoperative noninvasive testing before elective surgery. CHF, congestive heart failure; ECG, electrocardiogram; MET, metabolic equivalent; MI, myocardial infarction. (Redrawn from Eagle KA, Berger PB, et al: ACC/AHA guideline update for perioperative cardiovascular evaluation for noncardiac surgery—executive summary: A report of the American College of Cardiology/American Heart Association Task Force on Practice Guidelines [Committee to Update the 1996 Guidelines on Perioperative Cardiovascular Evaluation for Noncardiac Surgery]. J Am Coll Cardiol 39:542–553, 2002.)