Preoperative cardiovascular evaluation for noncardiac surgery

Cardiovascular complications following noncardiac surgery constitute an enormous burden of perioperative morbidity and mortality. Annually, more than one million operations are complicated by adverse cardiovascular events, such as perioperative myocardial infarction or death from cardiac causes. In order to combat this problem, cardiac evaluation prior to noncardiac surgery should ask two questions about the patient: What is the risk of cardiac complications during and after surgery? How can that risk be reduced or eliminated? Risk assessment evaluates patients' co-morbidities and exercise tolerance, as well as the type of surgery to be performed, to determine the overall risk of perioperative cardiac complications. Previous or current cardiac disease, diabetes and renal insufficiency all confer higher risks for perioperative cardiac complications. Poor exercise tolerance and high-risk surgical procedures (e.g., vascular, prolonged thoracic or abdominal operations) also predict worse perioperative outcomes. Noninvasive stress testing is widely used to help predict risk of perioperative complications, but the poor predictive power of these tests hampers their usefulness. After estimating the risk of cardiac complications, one should take measures to reduce it. Beta blockade has shown clear benefits in risk reduction. At this time, there are no data suggesting benefits of percutaneous coronary intervention or coronary artery bypass grafting in reducing noncardiac surgical risk. In addition, angioplasty with stenting and its attendant need for anticoagulation can expose patients to increased risk of perioperative bleeding. Thus, the use of coronary revascularization prior to noncardiac surgery should be reserved for those patients with an independent cardiac need for the procedure, such as unstable angina or stable angina refractory to medical therapy. In summary, patients with low clinical risk factors and good functional status, undergoing a low or intermediate risk surgery, have an excellent prognosis and may proceed to surgery without further delay. In addition, stable patients who have previously undergone coronary revascularization may also safely undergo surgery. Patients requiring urgent surgery should proceed immediately, since the consequences of delay usually outweigh the benefits of preoperative risk assessment. However, elective surgery should be indefinitely deferred for those patients with unstable coronary syndromes, since consequences of the cardiac disease usually negate the benefits of surgery. Controversy involves the intermediate or high clinical risk patient considering high-risk, but elective, surgery. Noninvasive testing offers only limited assistance in estimating risk for these patients. The best risk reduction strategy for these patients is perioperative beta blockade use. The role of coronary revascularization specifically to reduce perioperative cardiac complications remains unproven.