A 50-year-old man comes to the physician for a preventive visit. He has no chest pain or shortness of breath but does complain of occasional left posterior calf pain. The pain occurs most often with walking in the course of his job as a postal carrier, but he occasionally has leg cramps at rest. His other medical problems include diet-controlled diabetes mellitus and hypertension, but he does not take any medication regularly. The patient was hospitalized for chest pain 2 years ago. Cardiac stress test at that time was negative and he has had no recurrence. The patient has a 30-pack-year smoking history but does not use alcohol or illicit drugs. His father died suddenly at age 60, and his mother had a stroke in her 70s. His blood pressure is 138/92 mm Hg, pulse is 88/min, and body mass index is 28 kg/m². Heart and lung examinations show no abnormalities. Popliteal, dorsalis pedis, and posterior tibial pulses are palpable bilaterally. An electrocardiogram shows normal sinus rhythm. His hemoglobin A1c level is 7.2%. Which of the following is the most appropriate next step in management of this patient?

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11ec25c8_d8af_f626_bc81_53fdd9142950_MD0003_00 This patient has multiple risk factors for atherosclerosis (diabetes, hypertension, and smoking) and symptoms consistent with intermittent claudication. The next step in management should be to obtain physiologic testing with ankle-brachial index (ABI) to confirm the presence of peripheral arterial disease (PAD) as a cause of his symptoms. ABI is an inexpensive and noninvasive vascular test used to confirm the diagnosis of PAD in such patients. It is defined as the ratio of resting systolic blood pressure at the ankle to the systolic brachial blood pressure. An ABI of <0.90 is considered diagnostic of occlusive PAD with a 90% sensitivity and 95% specificity in symptomatic patients. (Choice A) Abdominal ultrasound is a highly sensitive screening test for abdominal aortic aneurysm. Routine one-time screening for abdominal aortic aneurysm with abdominal ultrasound is recommended for men age 65-75 with a history of smoking, but it is otherwise not needed in patients without suspicious symptoms. (Choice C) Arterial ultrasound of the lower extremities is another noninvasive modality for diagnosing PAD. Arterial duplex ultrasound can be used to localize the site and severity of vascular obstruction. However, it is less sensitive and specific than ABI for the initial diagnosis of PAD. It is generally performed in symptomatic patients with abnormal ABI who are being considered for interventional procedures. (Choice D) This patient walks regularly as part of his job and has no symptoms suggestive of coronary artery disease. Exercise stress testing is not recommended for routine screening in asymptomatic patients. (Choice E) This patient's symptoms are not suggestive of peripheral neuropathy, and nerve conduction studies are not indicated. Educational objective: Ankle-brachial index is a noninvasive test that is highly sensitive and specific for peripheral arterial disease in symptomatic patients. It is the preferred first step to confirm the diagnosis in most cases. References: Peripheral artery disease: current insight into the disease and its diagnosis and management. (http://www.ncbi.nlm.nih.gov/pubmed/20592174) Peripheral arterial disease: identification and implications. (http://www.ncbi.nlm.nih.gov/pubmed/14581250)

A 50-Year-Old Man Comes to the Physician for a Preventive