Evaluation prior to elective total knee arthroplasty
A 63-year-old woman is evaluated in the preoperative clinic 3 weeks prior to elective total knee arthroplasty. Over the past 4 months, she has experienced progressive shortness of breath and lightheadedness when carrying laundry baskets up the basement stairs. An urgent care clinician recently attributed these symptoms to late-onset asthma and prescribed an albuterol inhaler, which provided no relief. She has knee osteoarthritis and hypertension treated with hydrochlorothiazide. She works as an archivist at a local historical society. On physical examination, blood pressure is 114/84 mm Hg, pulse is 72/min, and respirations are 15/min. The carotid upstrokes are delayed with diminished volume. Jugular venous pulsation is normal. Lungs are clear. Cardiac auscultation reveals a grade 3/6 late-peaking systolic ejection murmur heard loudest at the right second intercostal space that radiates to both carotid arteries. The second heart sound is soft and single, and an S4 is present. Electrocardiogram demonstrates sinus rhythm with voltage criteria for left ventricular hypertrophy and secondary repolarization changes. Which of the following is the most appropriate next step in management?
See the answer and explanation below:
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D
Explanation
Clinical Pearl:
Clinically suspected severe aortic stenosis, identified by a late-peaking systolic murmur, delayed carotid upstroke, and attenuated second heart sound, requires preoperative transthoracic echocardiography before elective noncardiac surgery. In symptomatic patients, elective surgery must be deferred until the valvular defect is characterized and definitively addressed.
Explanation:
The patient presents with classic signs and symptoms of symptomatic severe aortic stenosis, including exertional dyspnea, presyncope, a narrow pulse pressure, delayed and diminished carotid upstrokes (pulsus parvus et tardus), a late-peaking systolic ejection murmur radiating to the carotids, and an attenuated second heart sound. Preoperative evaluation with transthoracic echocardiography is the necessary next step, as society guidelines establish a clear indication for echocardiography to assess suspected moderate or severe valvular disease before elective noncardiac surgery, which should be postponed until the hemodynamic severity is defined. Exercise treadmill electrocardiographic stress testing is contraindicated in symptomatic severe aortic stenosis because fixed cardiac output can precipitate severe hypotension, malignant ventricular arrhythmias, or cardiac arrest during exertion. Preoperative initiation of oral metoprolol therapy is contraindicated because acute beta-blockade without careful longitudinal titration increases perioperative mortality and stroke, and decreasing inotropy in fixed outflow obstruction can precipitate acute heart failure. Proceeding directly with the planned surgery is unsafe because uncharacterized severe aortic stenosis dramatically elevates the risk of perioperative myocardial infarction and death, particularly under the vasodilation induced by anesthetic agents. Twenty-four-hour ambulatory electrocardiographic rhythm monitoring is not indicated because the patient's symptoms are reproducibly exertional and driven by a mechanical outflow obstruction rather than an underlying paroxysmal cardiac arrhythmia.
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