The Correct Answer is B!
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A 67 year-old man with hypertension, hyperlipidemia, type 2 diabetes, and a 60-pack year smoking history presents to clinic complaining of progressively worsening bilateral leg pain that occurs when walking briskly on the treadmill over the last 3 months. The pain is located in the posterior distal thigh and calf and is worse on the right side. He notes that the pain is relieved by rest. His medications are enalapril, hydrochlorthiazide, metformin, aspirin, and atorvastatin. On exam, the blood pressure is 149/80 mm Hg, heart rate is 74 beats per minute. Cardiac exam reveals normal S1 and S2 with no extra heart sounds or murmurs. The lungs are clear. There is a right femoral artery bruit with diminished pulses. The extremities are cool with mild dependent rubor, but no edema.
What should be the next step in the management of this patient?
- Obtain an exercise treadmill test with ABI
- Obtain resting ankle-brachial index (ABI)
- Obtain magnetic resonance angiography (MRA) of the lower extremities
- Schedule the patient for contrast angiography of the lower extremities
In this patient with suspected peripheral arterial disease (PAD) of the lower extremities, non-invasive testing should be the first choice to establish a diagnosis. A resting arterial Doppler evaluation to calculate the ankle-brachial index (ABI) is the most appropriate test here. According to the ACC/AHA guidelines, lower extremity PAD should be suspected in individuals with 1 or more of the following: exertional leg symptoms, nonhealing wounds, age 65 or older, or 50 years and older with a history of smoking or diabetes. ABI should be measured in both extremities. ABI results are interpreted as follows: normal 1.00-1.40, borderline 0.91-0.99, abnormal 0.9 or less, and greater than 1.40 noncompressible (suggesting calcified vessels). Exercise treadmill tests with ABI can also be used to confirm PAD. However, it is not a first line test, rather, it is performed in patients who are at risk for lower extremity PAD but have a normal ABI, have no classical claudication symptoms, and have no other evidence of atherosclerosis. Other indications for exercise treadmill testing include assessment of functional limitations of claudication, functional capacity prior to exercise training/rehabilitation, and response to therapy. MRA of the extremities can be useful in the diagnosis of PAD but typically is not used as an initial screening exam. It is useful for identifying anatomic location and degree of PAD and thus is useful in selecting patients who may be candidates for endovascular intervention or surgical bypass. Contrast angiography would not be indicated for this patient at this time. After establishing a diagnosis of PAD, angiography can be used characterize arterial anatomy and is recommended for evaluation of patients that are candidates for revascularization.
1. Source: "Comparative Analysis of Pre/Post Assessments of Live/Didactic Course Attendees when compared to Mico-Learning/Online Course Users., "Knowledge to Practice, 2017.