Peripheral artery disease (PAD) is caused by atherosclerosis that leads to the narrowing or obstruction of the peripheral arteries, most commonly those that supply blood to the legs. The classic symptom is intermittent claudication—reproducible pain in the lower extremities consistently induced by exercise and relieved with rest. However, only about 10% of patients with PAD present with classic symptoms of claudication. Patients who have symptoms suggestive of PAD should undergo diagnostic testing using the ankle-brachial index (ABI). An ABI value of 0.9 or less is consistent with a diagnosis of PAD. An exercise ABI should be considered if ABI is normal and there is a high clinical suspicion for PAD. An ABI of 1.4 or greater is considered inconclusive or noncompressible and warrants further evaluation with alternative testing. This is most common in patients with diabetes and end-stage renal disease. Treatment for PAD includes structured exercise therapy, a single antiplatelet medication (clopidogrel preferred), a high-intensity statin, blood pressure control, antidiabetic agents (glucagon-like peptide-1 receptor agonists and sodium-glucose cotransporter-2 inhibitors), and smoking cessation when applicable. Patients who do not improve with initial treatment and those with chronic limb-threatening ischemia should be evaluated for revascularization, using imaging to determine the location and severity of arterial disease. Patients with acute limb ischemia require urgent evaluation to preserve limb viability.
Case 1. PM is a 62-year-old patient who has well-controlled high blood pressure and dyslipidemia. He tells you that he has recently cut back on his daily walks because of leg pain.
Peripheral artery disease (PAD) is caused by atherosclerotic obstruction of the peripheral arteries, most commonly those that supply blood to the legs. It affects approximately 8.5 million people in the United States.1 Patients with PAD have higher cardiovascular morbidity and mortality than people without PAD.2 It is clinically divided into four categories: asymptomatic PAD, chronic symptomatic PAD, chronic limb-threatening ischemia, and acute limb ischemia.3 Patients may progress between categories throughout the disease process, with estimates of progression from asymptomatic to symptomatic PAD ranging from 5% over 5 years to as high as 21% within 1 year.4
Evaluation
SCREENING
In its I statement, the US Preventive Services Task Force concluded that there is insufficient evidence to support routine PAD screening in asymptomatic patients.5,6 There is no strong evidence that diagnosing and treating asymptomatic patients leads to improvement in morbidity or mortality.6 According to the American College of Cardiology/American Heart Association guideline, clinicians may consider screening for PAD using an ankle-brachial index (ABI) in asymptomatic patients at increased risk.3 Risk factors include age 65 years or older; age 50 to 64 years with atherosclerotic risk factors, chronic kidney disease, or a family history of PAD; age younger than 50 years with diabetes and one additional atherosclerotic risk factor; or known atherosclerotic disease.3
SYMPTOMS
Claudication is the classic symptom of PAD, characterized by reproducible pain in the lower extremities (calf, thigh, or buttocks) that occurs during walking or other exercise and is typically relieved by rest within 10 minutes.3 However, only about 10% of patients with PAD experience typical symptoms of claudication.1 Patients may also present with atypical lower-extremity symptoms, including atypical pain, leg weakness, numbness, or fatigue.3 As the disease progresses to chronic limb-threatening ischemia, patients may report ischemic pain at rest, which often affects the forefoot, worsening with limb elevation and improving with dependency.3 These patients may also report a history of nonhealing or slow-healing wounds in the lower extremities.3 Acute limb ischemia is not always a progression of chronic limb-threatening ischemia; it can be caused by embolism, thrombosis, trauma, or peripheral aneurysm with distal embolization.3 In acute limb ischemia, patients may have an acute presentation (less than 2 weeks) of symptoms that can include pain, pallor, pulselessness, poikilothermia (unregulated body temperature), paresthesia (abnormal tingling, prickling, or burning sensation on the skin), and even paralysis of the affected limb.3
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