In this issue of American Family Physician, Karnath1 discusses preoperative risk assessment based on guidelines from the American College of Cardiology/American Heart Association and the American College of Physicians. Perioperative cardiac complications, which affect a significant number of patients, cause substantial economic burden.2 Such complications are an important clinical and public health issue, and a simple, common-sense approach to this problem would be extremely useful.
A simple approach would be to remove the focus from the perioperative moment and instead focus carefully on the patient presenting for evaluation. A good starting point is to obtain a thorough and complete history, which will provide information on possible previous or current coronary artery disease (CAD), diabetes mellitus, congestive heart failure (CHF), vascular disease, and hypertension, all of which are markers of a long-term adverse prognosis. Physical examination, simple laboratory tests, such as hematocrit, renal function, and electrolytes, and electrocardiography (ECG) provide incremental information. Physical examination should include evaluation of general appearance (e.g., cyanosis, pallor, dyspnea during conversation/minimal activity, Cheyne-Stokes respiration, poor nutritional status, obesity, skeletal deformities, tremor, anxiety), examination for elevated jugular venous pressure, assessment of arterial pulses, and auscultation for a third heart sound and murmur of aortic stenosis. If functional capacity cannot be adequately assessed by a careful history, an exercise ECG may be useful for the assessment of functional capacity, which helps with further risk stratification.
For patients with intermediate cardiac risk factors (i.e., occurrence of myocardial infarction more than one month earlier, mild angina, compensated or previous CHF, diabetes mellitus, and renal insufficiency), determining functional capacity by estimation using the Duke Activity Status Index or stress testing can help to further stratify patient risk. Intermediate-risk patients with poor functional capacity undergoing any noncardiac surgery or those with moderate or excellent functional capacity undergoing high-risk surgery should have noninvasive testing to further assess cardiac risk.3
Next, after assessing the likely presence or absence of these possibilities, consider what works for each of these conditions (i.e., CAD, diabetes mellitus, CHF, hypertension, and vascular disease). Patients with vascular disease have atherosclerosis by definition and should be treated as aggressively as patients with known CAD. Recent data have shown that patients with diabetes have the same long-term risk as those with known coronary disease,4 and aggressive risk factor modification is indicated in these patients. Medications currently known to improve prognosis in patients with CAD include aspirin, beta blockers, statins, and angiotensin-converting enzyme (ACE) inhibitors. In the perioperative period, however, only beta blockers have been shown to significantly decrease cardiac events and mortality.2
Targets for blood pressure control have been clearly defined,5 and these guidelines should be followed. Beta blockers are useful in patients with new or inadequately controlled hypertension who are about to undergo noncardiac surgery and in patients with renal insufficiency that is thought to be caused by diabetes, hypertension, or both. Patients with CHF caused by systolic dysfunction benefit from the use of beta blockers and ACE inhibitors. Appropriate use of these medications will not only reduce perioperative complications but also improve long-term prognosis. Effective perioperative medicine is essentially identifying and treating the clinical conditions that a patient has. In many patients, it represents a unique opportunity to improve long-term prognosis in those who have not previously sought medical care and, therefore, are not benefiting from therapy that would have been indicated in the past and present.
Coronary revascularization in the form of coronary artery bypass grafting or percutaneous coronary revascularization should be limited to patients who have a clearly defined indication for the procedure that is independent of the need for noncardiac surgery.6 We need to ask ourselves whether we would consider revascularization if the patient were not undergoing noncardiac surgery. If the answer is yes and noncardiac surgery is elective, then revascularization is indicated.
Overall, the management of patients presenting for perioperative evaluation remains identical to that of patients presenting for a general evaluation. The goal is to modify their risk factors and institute appropriate therapy that will improve their long-term prognosis. Institution of such measures will also reduce their perioperative risk.