Test your medicine knowledge with the MKSAP challenge, in partnership with the American College of Physicians.

A 74-year-old woman is evaluated during a routine examination. Her medical history is significant for hypertension and obesity. She is a former smoker, stopping 5 years ago. Medications are amlodipine, lisinopril, and aspirin.

On physical examination, she is afebrile, blood pressure is 136/78 mm Hg, pulse rate is 68/min, and respiration rate is 15/min. BMI is 32. The lungs are clear to auscultation, and no murmurs are noted. A bruit is heard over the left femoral artery.

The right ankle-brachial index is 1.2 and the left is 0.81.

Which of the following is the most appropriate management?

A: Initiate atorvastatin
B: Initiate cilostazol
C: Initiate warfarin
D: Obtain CT angiography
E: Obtain segmental limb pressures

MKSAP Answer and Critique

The correct answer is A: Initiate atorvastatin.

The most appropriate management is to start a moderate- or high-intensity statin. Peripheral arterial disease (PAD) is strongly associated with smoking, diabetes mellitus, and aging. PAD is defined noninvasively by calculation of the ankle-brachial index (ABI). An ABI of 0.90 or below is diagnostic of PAD. Most patients with PAD are asymptomatic; approximately 25% have symptoms referable to circulatory compromise. PAD is considered a coronary artery disease risk equivalent and statin therapy has been demonstrated to lower cardiovascular events in patients with PAD.

Exercise and cilostazol are effective therapies for patients with stable symptomatic PAD. Cilostazol significantly increases pain-free walking time and maximal walking time, although the gains with structured exercise are two- to three-fold greater than with cilostazol alone. Since this patient is asymptomatic, cilostazol is not indicated.

Antiplatelet therapy is indicated for all patients with symptomatic PAD, previous lower extremity revascularization, or amputation due to PAD. Antiplatelet therapy is reasonable in patients with asymptomatic PAD, particularly if they have evidence of atherosclerosis elsewhere (coronary or cerebral arteries). Combination treatment with an antiplatelet agent and warfarin, and warfarin monotherapy (adjusted to an INR of 2.0-3.0), is no more effective than antiplatelet therapy alone and carries a higher risk of life-threatening bleeding.

Noninvasive angiography is performed for anatomic delineation of PAD in patients requiring surgical or endovascular intervention. CT angiography (CTA) is rapid and easily available but requires the administration of intravenous contrast dye. While CTA compares favorably with digital subtraction (invasive) angiography for the detection of occlusive arterial disease, imaging is not needed at this time because the patient does not require surgical intervention.

Lower extremity segmental pressure measurement can help determine the level and extent of PAD. Using specialized equipment in the vascular laboratory, blood pressures are obtained at successive levels of the extremity, localizing the level of disease. Many vascular laboratories use air plethysmography to measure volume changes within the limb, in conjunction with segmental limb pressure measurement. Lower extremity segmental pressure measurement is not needed at this time because localization of disease is not needed to guide therapy, such as would be required if surgical intervention were being planned.

Key Point

• Patients with peripheral arterial disease should be treated with a moderate- or high-intensity statin.

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