Peripheral artery disease (PAD) is an abnormal narrowing of arteries other than those that supply the heart or brain. When narrowing occurs in the heart, it is called coronary artery disease, and in the brain, it is called cerebrovascular disease. Peripheral artery disease most commonly affects the legs, but other arteries may also be involved – such as those of the arms, neck, or kidneys. The classic symptom is leg pain when walking which resolves with rest, known as intermittent claudication. Other symptoms include skin ulcers, bluish skin, cold skin, or abnormal nail and hair growth in the affected leg. Complications may include an infection or tissue death which may require amputation; coronary artery disease, or stroke. Up to 50% of people with PAD do not have symptoms.The greatest risk factor for PAD is cigarette smoking. Other risk factors include diabetes, high blood pressure, kidney problems, and high blood cholesterol. The most common underlying mechanism of peripheral artery disease is atherosclerosis, especially in individuals over 40 years old. Other mechanisms include artery spasm, blood clots, trauma, fibromuscular dysplasia, and vasculitis. PAD is typically diagnosed by finding an ankle-brachial index (ABI) less than 0.90, which is the systolic blood pressure at the ankle divided by the systolic blood pressure of the arm. Duplex ultrasonography and angiography may also be used.
PAD carries a greater than "20% risk of a coronary event in 10 years".The risk is low that an individual with claudication will develop severe ischemia and require amputation, but the risk of death from coronary events is three to four times higher than matched controls without claudication. Of patients with intermittent claudication, only "7% will undergo lower-extremity bypass surgery, 4% major amputations, and 16% worsening claudication", but stroke and heart attack events are elevated, and the "5-year mortality rate is estimated to be 30% (versus 10% in controls)". Epidemiology
The prevalence of PAD in the general population is 3–7%, affecting up to 20% of those over 70; 70%–80% of affected individuals are asymptomatic; only a minority ever require revascularisation or amputation. Peripheral artery disease affects one in three diabetics over the age of 50. In the US, it affects 12–20 percent of Americans age 65 and older. Around 10 million Americans have PAD. Despite its prevalence and cardiovascular risk implications, only 25% of PAD patients are undergoing treatment.In people aged 40 years and older in the United States in 2000, rates of PAD was 4.3%. Rates were 14.5% people aged 70 years or over. Within age groups, rates were generally higher in women than men. Non-Hispanic blacks had a rates of 7.9% compared to 4.4% in Non-Hispanic whites and 3.0% (1.4%–4.6%) in Mexican Americans.The incidence of symptomatic PAD increases with age, from about 0.3% per year for men aged 40–55 years to about 1% per year for men aged over 75 years.