Peripheral arterial disease (PAD) is a clinical disorder leading to stenosis or occlusion of the noncardiac vessels. Atherosclerosis is the most common cause in adults over the age of 50 years. Risk factors for developing PAD include older age (affecting 10%-15% of individuals 65 years and older and 15%-20% of individuals 80 years and older), family history, smoking, diabetes, hypertension, hyperlipidemia (including elevated lipoprotein[a]), and homocysteinemia. In the United States, PAD is approximately twice as common in Black individuals as it is in non-Hispanic White individuals.

Symptoms develop when the metabolic demand of tissues is greater than vessels are able to deliver. Most patients with PAD are asymptomatic or have atypical symptoms. In those who develop symptoms, look for extremity pain with activity that is relieved with rest (claudication), limb ischemia with the development of ulcers or gangrenous lesions, or critical acute limb ischemia leading to pallor, pulselessness, paresthesia, and poikilothermia. Individuals with PAD and diabetes are at higher risk for walking impairment, below‑the‑knee atherosclerosis and limb amputation, and mortality.

Atherosclerosis is a type of arteriosclerosis that can lead to narrowing of blood vessels. When atherosclerotic plaques involve 70%-80% of the luminal diameter, blood flow may become limited, particularly during times of physical exertion and increased demand. Plaque rupture may cause occlusion of coronary vessels or cerebrovascular vessels, leading to ischemia and infarction that present as myocardial infarctions and strokes, respectively.