What pre-operative cardiac evaluation of patients undergoing intermediate-risk surgery is most appropriate?
Case
The orthopedic service asks you to evaluate a 76-year-old woman with a hip fracture. She has diabetes, hypertension, and hyperlipidemia but no known coronary artery disease (CAD). She says she can carry a bag of groceries up one flight of stairs without chest symptoms.
Her physical exam is significant only for a shortened, internally rotated right hip. Her blood pressure is 160/88 mm/hg, her pulse is 75 beats per minute, and her respiratory rate is 16 breaths a minute with an oxygen saturation of 95% on one liter. Her creatinine is 1.2 mg/dL, and her fasting glucose is 106 mg/dL. An electrocardiogram reveals normal sinus rhythm without evidence of prior myocardial infarction (MI).
Her medications are lisinopril, atorvastatin, aspirin, fluoxetine, and diazepam. She is scheduled for the operating room tomorrow. What is the best strategy to evaluate and minimize her perioperative cardiac risk, and does it include a beta-blocker?
Overview
There are many ways to identify patients at risk for perioperative cardiac complications—but few simple, safe, evidence-based means of mitigating risk.1
Over the past 10 years, the general approach has been that preoperative revascularization is beneficial in a limited number of clinical scenarios. Further, beta-blockers reduce risk in nearly all other high- and intermediate-risk patients. Unfortunately, routine perioperative administration of beta-blockers to intermediate-risk patients is not supported by trial evidence and may expose these patients to increased risk of adverse outcomes—including death and stroke.
Review of the Data
Intermediate-risk patients: Inter-mediate risk patients have recently been redefined as patients with a Revised Cardiac Risk Index (RCRI) score of two or one (See Table 1, p. 27).2,3 Older guidelines suggested noninvasive testing for such patients if they had poor functional capacity (less than four metabolic equivalents [METS]) and were undergoing intermediate-risk surgery, including orthopedic, peritoneal, and thoracic procedures.
Unfortunately, this situation is common, leading to frequent testing and unclear benefit to patients. Omission of a noninvasive evaluation in intermediate-risk orthopedic surgery patients is not associated with an increase in perioperative cardiac events.4 Most events occur in patients who did not meet criteria for preoperative testing.
The 2007 ACC/AHA Guidelines for Perioperative Evaluation and Care address this by recommending noninvasive testing only “if it will change management.” But they offer little guidance in unclear clinical situations, such as the urgent hip-fracture repair needed by our patient.
