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Cardiovascular disease, commonly encountered in the perioperative setting, is the leading cause of death in the United States. Patients with cardiovascular disease in the perioperative setting have elevated catecholamine levels associated with the stress response to surgery. The stress response increases myocardial oxygen demand and the risk for myocardial ischemia.
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The first step in applying the risk stratification approach recommended by the American College of Cardiology and the American Heart Association (ACC/AHA) Guidelines on Perioperative Cardiovascular Evaluation and Care for Noncardiac Surgery is to determine if a patient possesses specific medical conditions identified as high risk for noncardiac surgery (Figure 52-1). The guidelines separate this assessment into active cardiac conditions, comorbid diseases, and functional status. The active cardiac conditions identified include unstable coronary syndromes, decompensated heart failure, significant arrhythmias, and severe valvular heart disease (Table 52-1). Patients with active cardiac conditions require further evaluation prior to undergoing elective, noncardiac surgery. Comorbid diseases that increase perioperative cardiovascular event risk are defined as peripheral vascular disease, cerebrovascular disease, diabetes, renal impairment, and chronic pulmonary disease. A thorough history includes inquiries into the presence and severity of these associated conditions. Finally, an assessment of functional status correlates tolerance for daily activities with metabolic capacity for oxygen uptake (Figure 52-2). Functional status is measured in metabolic equivalents (METs) with 1 MET representing the oxygen consumption of an average person at rest (3–5 mL/kg/min). In general, a patient with cardiac risk factors tolerating > 4 METs of activity is less likely to need further evaluation than a sedentary patient with the same risk factors.
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