Hospitalists and internists are frequently called upon to perform preoperative medical consultations, and cardiac risk assessment is what is most often requested. Preoperative evaluation is now part of the core curriculum for Hospital Medicine, but when surveyed a number of years ago, many hospitalists felt inadequately trained to do this.
Preoperative cardiac risk assessment has evolved over the past 40 years from a simple global assessment of a patient's physical status (the ASA classification) to multivariate risk analyses (Goldman, Detsky) to a simplified scoring system (Lee RCRI) to guidelines from the American College of Cardiology/American Heart Association, American College of Physicians (ACC/AHA, ACP). The most current of these is the ACC/AHA guidelines for perioperative cardiac evaluation and management, originally published in 1996 and updated in 2007 to incorporate the RCRI factors. Using these guidelines and selective cardiac testing (pharmacologic stress tests), physicians are now better able to provide a more accurate assessment of perioperative risk, and the focus has turned to risk reduction strategies. These include revascularization by coronary artery bypass grafting (CABG) or percutaneous coronary intervention (PCI), medical therapy (beta-blockers, alpha-agonists, statins), and other intraoperative measures (normothermia, anesthetic technique). Although surgical and anesthetic techniques have improved and perioperative cardiac events have decreased, operative mortality and cardiac morbidity remain significant, especially among high-risk patients or high-risk procedures.
This chapter reviews the current state of the art for perioperative risk assessment and risk reduction in patients with cardiac disease.
Goldman and colleagues published the first large prospective multivariate analysis of preoperative cardiac risk. They identified nine independent predictors of death or major postoperative cardiac complications. These risk factors were assigned points based on their relative importance, and the event rates were correlated with the point total in this risk index. Detsky and colleagues modified this risk index by expanding the list of risk factors and combining this with the pretest probability of complications based on the risk of the surgery itself. Eagle and colleagues identified five factors—age, diabetes mellitus (DM), angina, myocardial infarction (MI), and heart failure—associated with perioperative cardiac events and used these to stratify risk and decide when to do further cardiac testing. Most recently Lee and colleagues identified and validated six factors associated with increased risk of perioperative complications. These factors were high-risk surgery, coronary artery disease (CAD), heart failure, cerebrovascular disease (stroke or transient ischemic attack), DM requiring insulin, and renal insufficiency (creatinine > 2.0 mg/dL). These studies, using simple clinical evaluation (history, physical examination, and basic laboratory studies) found many similar factors predicting increased risk of perioperative cardiac complications and helped refine preoperative risk stratification.
- Active clinical conditions are unstable coronary syndromes (MI < 30 days, unstable or severe angina), decompensated heart failure, hemodynamically significant arrhythmias, or severe (symptomatic) valvular heart disease.
A detailed history and focused physical examination are key in clinical risk assessment, and a few ...