Updated guidelines for perioperative cardiovascular evaluation for noncardiac surgery - Practice Guidelines

American Family Physician,  Sept 15, 2002  by Barrett M. Schroeder

• E-mail
• Print
• Link

A committee for the American College of Cardiology/ American Heart Association (ACC/AHA) Task Force on Practice Guidelines recently updated the 1996 guidelines on perioperative cardiovascular evaluation for noncardiac surgery. The executive summary of the revised guidelines was published in the March 12, 2002 issue of Circulation.

Beyond providing medical clearance for surgery, the preoperative cardiac evaluation has these purposes:

* To evaluate the patient's current medical status.

* To make recommendations on the risk, evaluation, and management of cardiac problems during the perioperative period.

* To provide a clinical risk profile for use in making treatment decisions that may affect short- and long-term cardiac outcomes.

The goals of the perioperative evaluation are to assess cardiac risk, determine the most appropriate tests and treatments for optimal patient care, and contain costs by avoiding unnecessary testing.

The predominant theme of the ACC/AHA updated guidelines is that preoperative intervention is rarely required for the sole purpose of lowering surgical risk. The classifications of evidence used in summarizing the indications for specific treatments are provided in Table 1. (1)

Preoperative Evaluation

The history, physical examination, and electrocardiogram (ECG) are directed at identifying preexisting cardiac disease and other conditions that may increase perioperative risk. Disease severity and stability, as well as previous treatments, also need to be determined.

Functional capacity, which can be expressed in metabolic equivalent (MET) levels, can be an important factor. A patient who cannot meet a 4-MET demand with most normal daily activities has increased perioperative cardiac and long-term risks. Energy requirements for various activities can be estimated using a questionnaire (Table 2). (1-3)

Other factors that can help determine cardiac risk include the patient's age and comorbid conditions. Significant comorbid conditions include chronic pulmonary disease, diabetes mellitus, renal dysfunction, and peripheral vascular disease. Cardiac risk is also higher with certain surgeries, such as vascular procedures and complicated, prolonged abdominal, thoracic, and head and neck procedures.

Conditions that have been associated with an increased risk of perioperative morbidity include coronary artery disease, heart failure, a history of cerebrovascular disease, an elevated creatinine level (greater than or equal to 2 mg per dL [180 [micro]mol per L]), diabetes requiring insulin treatment, and high-risk surgery. Based on consensus, the ACC/AHA committee divided markers (predictors) of clinical risk into three categories (Table 3). (1,4)

STEPWISE APPROACH TO PERIOPERATIVE CARDIAC ASSESSMENT

A proposed stepwise approach for determining which patients are most likely to benefit from preoperative coronary assessment and treatment is provided in Figure 1. (1) This approach depends on assessment of clinical predictors, previous coronary evaluation and treatment, functional capacity, and surgery-specific risk. Steps corresponding to the algorithm are described in Table 4. (1,5)

Specific Preoperative Cardiovascular Conditions hypertension

Stage 3 hypertension (180/110 mm Hg or higher) should be controlled preoperatively. Effective control often can be achieved with outpatient treatment for several days to weeks before surgery. For more urgent surgery, blood pressure can be lowered with rapid-acting agents. Antihypertensive therapy is continued through the perioperative period.

VALVULAR HEART DISEASE

To lower the risk of perioperative heart failure or shock, symptomatic stenotic lesions often require percutaneous valvotomy or valve replacement before noncardiac surgery. Patients with symptomatic regurgitant valvular disease may be stabilized with intensive medical therapy and monitoring before surgery, with definitive treatment given later.

When delaying noncardiac surgery may have serious consequences, medical therapy and monitoring are appropriate. Exceptions may include severe valvular regurgitation with a reduction in left ventricular function. In these patients, limited hemodynamic reserve increases the likelihood of destabilization during perioperative stresses.

MYOCARDIAL DISEASE

Patients with dilated and hypertrophic cardiomyopathy are at increased risk for perioperative heart failure. In these patients, preoperative management is directed at maximizing hemodynamic status. An estimate of hemodynamic reserve can be helpful in anticipating potential complications. Intensive medical therapy and monitoring are provided after surgery.

ARRHYTHMIAS

Patients with arrhythmias or cardiac conduction disturbance should be evaluated for underlying cardiopulmonary disease, metabolic abnormality, or drug toxicity. Treatment for the underlying cause of a symptomatic or hemodynamically significant rhythm disturbance should be initiated; the arrhythmia should also be treated.

Aggressive perioperative monitoring or treatment of frequent premature ventricular beats and asymptomatic nonsustained ventricular tachycardia generally is not necessary. These rhythm disturbances have not been associated with an increased risk of nonfatal myocardial infarction or cardiac death.