Leg artery disease, also called peripheral artery disease (PAD), refers to a partial or complete blockage of the circulation to the legs and feet.
The risk factors for PAD include diabetes mellitus, smoking, high blood pressure, high blood cholesterol, male gender, advanced age, and a sedentary lifestyle.
Discomfort in a muscle group of the leg while walking, a phenomenon called intermittent claudication, is a common symptom of leg artery disease.
Leg artery disease is a partial or complete blockage of circulation through the arteries of the leg. This compromised blood flow can cause problems in the hip, buttock, thigh, knee, shin, or upper foot. Atherosclerosis, or hardening of the arteries, is considered the primary cause.
WHAT ARE THE SYMPTOMS?
Many cases of leg artery disease are 'silent,' meaning that the person with the disease does not yet experience any noticeable symptoms (asymptomatic). Asymptomatic peripheral artery disease (PAD), however, is a serious issue. Even though the patient feels well, he or she is at significantly increased risk of suffering a heart attack or stroke.
Discomfort in the legs is a common first symptom of leg artery disease. Called intermittent claudication, or IC, the discomfort usually occurs in large muscles in one or both legs during exercise, such as walking. Not every person with PAD experiences leg pain. Some people may feel a tightness, heaviness, cramping, or weakness in the leg.
When people experience intermittent claudication, the discomfort tends to occur consistently, typically each time a person walks a certain distance, and fades away within a few minutes after a person stops to rest. As leg artery disease progresses, leg pain may occur at shorter and shorter walking distances.
Eventually a person may feel pain in the arch of the foot, even at rest, when reduced blood flow prevents tissues from getting enough oxygen, a condition called critical limb ischemia. Many people with advanced leg artery disease report pain in the arches of their feet or in their toes while lying down.
In severe cases of leg artery disease, people may develop painful skin ulcers on their toes or feet.
CAUSES AND RISK FACTORS
As people age, the normal flow of blood through the legs and feet can be affected by the buildup of plaque inside the arteries. Over time, these plaques continue to grow on arterial walls as cholesterol circulates in the blood, and as the plaques enlarge the arteries become narrow and stiffened. This process is called atherosclerosis, commonly known as 'hardening of the arteries' because the plaque buildup thickens the walls of the arteries, narrowing the space through which blood flows. When this narrowing occurs in leg arteries, the circulation of blood through the leg is compromised. Poor circulation in turn can cause ischemia, or a decrease in blood flow that causes insufficient oxygen levels.
Atherosclerosis may also cause coronary heart disease (CHD) when plaque causes blockages in the arteries that bring blood to the heart muscle. Carotid artery disease, or plaque buildup that interferes with the flow of blood to the brain, is also caused by atherosclerosis. These conditions are serious because CHD can cause heart attacks, and carotid artery disease can result in stroke.
Physicians estimate that 30 to 40 percent of people with CHD or carotid artery disease also suffer from leg artery disease or another form of PAD, and that 50 to 60 percent of patients with PAD will develop either CHD or carotid artery disease.
A person's risk of developing leg artery disease increases with age, with people over age 50 being at greatest risk of developing the disease. More men than women tend to develop leg artery disease.
Other factors that contribute to the risk of developing leg artery disease are:
Hypertension, or high blood pressure;
High levels of cholesterol or triglycerides in the blood;
Being more than 30 percent over one's ideal weight; and
Having high levels of an amino acid called homocysteine in the blood.
Physicians can diagnose leg artery disease after performing a careful medical history and physical examination, which includes measuring the blood pressure in the legs, testing blood cholesterol levels, and listening to a person describe symptoms. Physicians also assess the strength of the pulse in arteries behind the knee and on the foot. Weak or absent pulses in those areas may indicate leg artery disease.
To test the blood pressure in a person's legs, physicians measure the ankle/brachial index, or ABI. This painless test combines a traditional blood-pressure device and Doppler ultrasound to compare the blood pressure in a person's arms to the blood pressure in that person's legs.
To provide more information about the extent of leg artery disease, doctors use other tests, including:
Pulse Volume Recording;
Magnetic Resonance Imaging; and/or
An endarterectomy can be performed to clear plaque from leg arteries.
Cases of leg artery disease that are detected early can be treated with exercise, weight reduction, control of blood sugar, reduction in blood pressure, cholesterol management, and the adoption of other healthy lifestyle changes.
Medications, such as those that help control blood pressure, lower cholesterol levels, and block platelets, are sometimes used to treat less-advanced cases of leg artery disease. While these drugs do not treat leg artery disease or its symptoms specifically, they can help prevent atherosclerosis from worsening, both in leg arteries and in coronary and carotid disease.
In many cases of leg artery disease, these kinds of changes and treatments are not enough. In some people, the leg artery disease is so advanced that it does not respond to lifestyle management changes.
Minimally invasive procedures such as angioplasty may be helpful for some advanced cases. For more advanced forms of leg artery disease, direct reconstruction of the circulation, usually with a surgical bypass graft or endarterectomy, may be needed to relieve symptoms.
As a last resort, when all treatments fail and the person's circulation is so severely compromised that leg tissue has become gangrenous, amputation or removal of the lower leg or foot may be required. In approximately 90 percent of the cases, however, amputation can be avoided or limited to the toes.