A 72-year-old obese woman is scheduled for right knee replacement due to osteoarthritis. She can barely walk due to severe knee pain. She has no chest pain, dyspnea, palpitations, or syncope. The patient has a history of hypertension and diet-controlled diabetes mellitus. She had an uncomplicated cholecystectomy for symptomatic gallstones 10 years ago.
Blood pressure is 152/75 mm Hg and pulse is 75/min and regular. BMI is 32 kg/m². A 3/6 late-peaking systolic murmur is heard at the right upper sternal border. S2 is soft with paradoxical splitting. The lungs are clear on auscultation. The abdomen is nontender. The right knee is deformed and tender with mild effusion. There is no peripheral edema.
ECG shows normal sinus rhythm, voltage criteria for left ventricular hypertrophy, and T-wave inversion in leads I, aVL, and V6. Serum creatinine is 1.1 mg/dL.
Which of the following is the best next step in management of this patient?

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11ec193a_9767_4e54_853d_d156efc01856_MD0002_00 The evaluation of perioperative cardiovascular risk for noncardiac surgery requires consideration of the type of surgery as well as patient-specific comorbidities and functional status. Several high-risk cardiac conditions necessitate further evaluation and/or management prior to even low-risk surgery; these include unstable coronary syndrome, decompensated heart failure, significant arrhythmia, and severe valvular disease. type of surgery prior to even low-risk surgery This patient's late-peaking 3/6 systolic murmur and paradoxical splitting of S2 (consistent with delayed closure of the aortic valve) suggest underlying severe aortic stenosis (AS). In addition, her sedentary lifestyle raises the possibility of markedly low cardiac reserve despite the lack of suggestive symptoms (eg, dyspnea, chest pain, syncope). Such patients with suspected severe AS should undergo transthoracic echocardiogram to assess left ventricular function and degree of valvular stenosis, and guide further management (eg, aortic valve replacement) prior to any noncardiac surgery. (Choice A) Cardiac catheterization prior to noncardiac surgery is indicated in patients with unstable angina or recent myocardial infarction. It may eventually be indicated in this patient if echocardiogram confirms severe AS (to assess coronary arteries prior to valve replacement surgery) or reveals left ventricular systolic dysfunction. (Choice B) Coronary calcium score is used primarily in asymptomatic patients for preventive screening of coronary atherosclerosis. It has no role in preoperative evaluation for noncardiac surgery. (Choice C) The patient's clinical presentation is suggestive of severe aortic AS, and echocardiogram should be performed prior to knee replacement surgery. Any surgery performed without additional evaluation and management likely carries very high perioperative cardiovascular risk. (Choice D) Noninvasive cardiac evaluation with exercise or pharmacologic stress test is not indicated in most asymptomatic patients undergoing noncardiac surgery. It should be considered only in patients with high perioperative risk based on the Revised Cardiac Risk Index (RCRI) and poor functional capacity (<4 METs) if the results will influence management. Although risk estimates vary, the American Board of Internal Medicine calculator uses these estimates for RCRI. Revised Cardiac Risk Index (RCRI) Educational objective: High-risk cardiac conditions that necessitate further evaluation and management prior to noncardiac surgery include unstable coronary syndrome, decompensated heart failure, significant arrhythmia, and severe valvular disease. Patients with known or suspected severe aortic stenosis should undergo transthoracic echocardiogram prior to any noncardiac surgery. __________ References: Usefulness of transthoracic echocardiography as a tool for risk stratification of patients undergoing major noncardiac surgery. (http://www.ncbi.nlm.nih.gov/pubmed/11230829) 2009 ACCF/AHA focused update on perioperative beta blockade incorporated into the ACC/AHA 2007 guidelines on perioperative cardiovascular evaluation and care for noncardiac surgery: a report of the American College of Cardiology Foundation/American Heart Association Task Force on Practice Guidelines. (http://www.ncbi.nlm.nih.gov/pubmed/19884473)

A 72-Year-Old Obese Woman Is Scheduled for Right Knee Replacement