High risk populations
Peripheral arterial disease is more common in these populations:
All people who have leg symptoms with exertion (suggestive of claudication) or ischemic rest pain
All people aged 65 years and over regardless of risk factor status
All people between 50 and 69 and who have a cardiovascular risk factor (particularly diabetes or smoking)
Age less than 50 years, with diabetes and one other atherosclerosis risk factor (smoking, dyslipidemia, hypertension, or hyperhomocysteinemia)
Individuals with an abnormal lower extremity pulse examination
Those with known atherosclerotic coronary, carotid, or renal artery disease
All people with a Framingham risk score of 10%–20%
All people who have previously experienced chest pain

Mechanism
As previously mentioned, the most common cause of peripheral artery disease, especially in patients over 40 years old, is atherosclerosis. Atherosclerosis is a narrowing of the arteries caused by lipid or fat build up and calcium deposition in the wall of the affected arteries. The most commonly affected site occurs at arterial branch points, because there is an increase in turbulence and stress on the artery at these areas where the artery branches to supply distant structures. Disease of distant structures, including feet and toes, are usually caused by diabetes and seen in the elderly population.Additional mechanisms of peripheral artery disease including arterial spasm, thrombosis, and fibromuscular dysplasia. The mechanism of arterial spasm is still being studied, but it can occur secondary to trauma. The symptoms of claudication ensue when the artery spasms, or clamps down on itself, creating an obstruction. Similar to atherosclerosis, this leads to decreased blood flow to the tissue downstream of the obstruction.
The prevalence of PAD varies considerably depending on how PAD is defined, and the age of the population being studied. Diagnosis is critical, as people with PAD have a four- to five-fold higher risk of heart attack or stroke.The Diabetes Control and Complications Trial, and the U.K. Prospective Diabetes Study trials, in people with type 1 and type 2 diabetes, respectively, demonstrated that glycemic control is more strongly associated with microvascular disease than macrovascular disease. Pathologic changes occurring in small vessels may be more sensitive to chronically elevated glucose levels than is atherosclerosis occurring in larger arteries. Research
Research is being done on therapies to prevent progression of PAD. In those who have developed critically poor blood flow to the legs, the benefit of autotransplantation of autologous mononuclear cells is unclear.Only one randomized controlled trial has been conducted comparing vascular bypass to angioplasty for the treatment of severe PAD. The trial found no difference in amputation-free survival between vascular bypass and angioplasty at the planned clinical endpoint, but the trial has been criticized as being underpowered, limiting endovascular options, and comparing inappropriate endpoints.