Peripheral artery disease (PAD) is a vascular condition that results in narrowing and hardening of the arteries that supply the legs and feet. While the overall prevalence of PAD ranges from 3% to 10%, PAD affects 12% to 20% of Americans aged 65 years and older.1,2 Of patients asymptomatic at baseline, 9% will develop the classic symptoms of intermittent claudication (IC) within five years.3 The prevalence of IC is 6% in persons with PAD older than age of 60 years.1 However, it is estimated only a quarter of these patients will experience a worsening of symptoms.1
Approximately 40% to 60% of patients with PAD also have coronary artery and cerebral artery disease,1 and 20% to 30% of those with IC will die within five years, mainly due to cardiovascular events.4 This is why the most vital goal of PAD treatment is the reduction of the patient’s cardiovascular risk.
Etiology
PAD is an occlusive disease of the large peripheral arteries (especially of the legs), excluding the coronary and intracranial vessels. The disease is associated with a resting ankle-brachial pressure index (ABPI) of ≤0.90, which is indicative of a hemodynamically significant arterial stenosis.1 Traditional risk factors include age, diabetes, smoking, obesity, and hypertension; nontraditional risk factors include race, chronic kidney disease, and hypercoagulable states.5
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PAD is primarily caused by atherosclerosis and results in either acute or chronic limb ischemia. The latter presents as IC, which is defined as pain in the leg muscles on walking.
Accumulated atheroma in the walls of arteries eventually leads to inadequate tissue perfusion. Atherosclerosis is a complex process involving endothelial dysfunction, thrombosis, platelet activation, lipid disturbances, oxidative stress, and genetic factors. Other less common causes of PAD include thrombus formation, emboli, and inflammatory processes resulting in vessel stenosis.1
In the late stages of the disease, long-term tissue hypoperfusion progresses to critical limb ischemia.
Classification
PAD can be categorized using the Fontaine (Table 1) or Rutherford (Table 2) classification system. Each system grades PAD from no symptoms to major tissue loss and can be used at diagnosis and to evaluate the progression or improvement of symptoms.
