Perioperative Cardiovascular Evaluation and Preparation for Noncardiac Surgery
The prevalence of cardiovascular disease increases progressively with advancing age. Moreover, the number of patients over 65 years of age is expected to increase by 25% to 35% over the next two decades. Cardiovascular complications account for 25% to 50% of deaths following noncardiac surgery.Perioperative myocardial infarction (MI), pul-monary edema, systolic and diastolic heart failure, arrhythmias, and thromboembolism are the most common diagnoses in patients with preexisting car-diovascular disease. The incidence of postoperative cardiogenic pulmonary edema is approximately 2% in all patients over 40 years of age, but it is 6% in patients with a history of heart failure and 16% in patients with poorly compensated heart failure. The relatively high prevalence of cardiovascular disorders in surgical patients has given rise to attempts to define cardiacrisk or the likelihood of intraoperative or postopera-tive fatal or life-threatening cardiac complications.
In 2007, the ACC/AHA Task Force Report pro-duced revised guidelines for perioperative evaluation. The revised guidelines stated that the patient’s medi-cal history is critical in determining the requirements for preoperative cardiac evaluation and that certain conditions (eg, unstable coronary syndromes and decompensated heart failure) warrant cardiology intervention prior to all but emergency procedures (Table 21–1). The history should also review any past procedures, such as cardioverter defibrillator implants, coronary stents, and other interventions.
Additionally, the patient’s ability to perform the tasks of daily living should be assessed as a guide to deter-mine functional capacity. A patient with a history of cardiac disease and advanced age, but good exercise tolerance, will likely have a lower perioperative risk than a similar individual with dyspnea after minimal physical activity (Table 21–2).The patient’s history should also seek signs of other disease processes that frequently accom-pany heart disease. Cardiac patients often present with obstructive pulmonary disease, reduced renal function, and diabetes mellitus.A physical examination should be performed on all patients, and the heart and lungs should be aus-cultated. The physical examination is especially use-ful in patients with certain conditions. For example, if a murmur suggestive of aortic stenosis is detected, additional ultrasound evaluation will likely be war-ranted, as aortic stenosis substantially increases the risks in patients undergoing noncardiac surgery.
The following conditions are associated with increased risk:
· Ischemic heart disease (history of MI, evidence on electrocardiogram [ECG], chest pain)
· Congestive heart failure (dyspnea, pulmonary edema)
· Cerebral vascular disease (stroke)
· High-risk surgery (vascular, thoracic, abdominal, orthopedic)
· Diabetes mellitus
· Preoperative creatinine >2 mg/dL
Recent ACC/AHA guidelines identify con-ditions that are a major cardiac risk and warrant intensive management prior to all but emergent surgery. These conditions include: unstable coro-nary syndromes (recent MI, unstable angina), decompensated heart failure, significant arrhyth-mias, and severe valvular heart disease. The ACC/ AHA guidelines identify an MI within 7 days, or one within 1 month with myocardium at risk for ischemia, as “active” cardiac conditions. On the other hand, evidence of past MI with no myocar-dium thought at ischemic risk is considered a low risk for perioperative infarction after noncardiac surgery.
The ACC/AHA guidelines suggest a stepwise approach to preoperative cardiac evaluation. Their recommendations are classified as follows:
· Class I: Benefits >> risk
· Class IIa: Benefits >> risk, but scientific evidence incomplete
· Class IIb: Benefits ≥ risk, and scientific evidence incomplete
· Class III: Risks >>benefits
Class I recommendations are as follows:
· Patients who have a need for emergency noncardiac surgery should proceed to the operating room with perioperative surveillance and postoperative risk factor management
· Patients with active cardiac conditions should be evaluated by a cardiologist and treated according to ACC/AHA guidelines
· Patients undergoing low-risk procedures should proceed to surgery
· Patients with poor exercise tolerance (<4 metabolic equivalents [METs]) and no known risk factors should proceed to surgery
Class IIa recommendations are as follows:
· Patients with a functional capacity >4 METs and without symptoms should proceed to surgery
· Patients with a functional capacity <4 METs or those with an unknown functional capacity with three or more clinical risk factors scheduled for vascular surgery should be tested, if management is likely to change based on the results
· Patients with a functional capacity <4 METs or those with an unknown functional capacity with three or more clinical risk factors scheduled for intermediate-risk surgery should proceed to surgery with heart rate control
· Patients with a functional capacity <4 METs or those with an unknown functional capacity with one or two clinical risk factors who are scheduled for vascular or intermediate-risk surgery should proceed to surgery with heart rate control
The ACC/AHA guidelines also note, as class IIb recommendations, that noninvasive testing might be considered if patient management changes in patients with poor or unknown functional capacity or in patients undergoing intermediate-risk surgery
with three clinical risk factors. Likewise, such test-ing might be indicated in patients with one or two clinical risk factors scheduled for vascular or inter-mediate-risk surgery. Table 21–3 classifies surgical procedures according to risk.
The ACC/AHA guidelines also provide specific recommendations regarding various conditions likely to be encountered perioperatively.
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