What Peripheral Artery Disease Is
Peripheral artery disease, often called PAD, occurs when arteries that carry blood to the legs become narrowed or blocked. The most common cause is a condition called atherosclerosis, which develops when fatty deposits accumulate inside the artery wall over many years.
These deposits are called plaque. Plaque is made up of cholesterol, calcium, inflammatory cells, and fibrous scar tissue. As plaque builds up, the inside of the artery becomes narrower. This reduces the amount of blood that can flow through the vessel.
When circulation becomes limited, the muscles in the legs may not receive enough oxygen during physical activity. This can lead to symptoms such as pain or cramping when walking. PAD most often affects the arteries that supply the legs and feet, but the same disease process can also affect arteries in the heart and brain. Because of this, PAD is considered both a circulation problem in the legs and a cardiovascular disease.
Understanding PAD
How Atherosclerosis Develops
Atherosclerosis is the gradual buildup of plaque inside the artery wall.
This process typically develops over many years and is influenced by several factors, including smoking, diabetes, high cholesterol, and high blood pressure. The inner lining of a healthy artery is smooth and flexible. This allows blood to flow easily. Over time, damage to the artery lining can trigger inflammation. Cholesterol and inflammatory cells begin to accumulate in the vessel wall.
As plaque grows, the artery becomes narrower and less flexible.
In some cases, plaque may also become unstable and trigger blood clot formation, which can suddenly worsen circulation. Atherosclerosis is a progressive disease, but its progression can often be slowed with lifestyle changes, medications, and appropriate medical care.
Arteries That Supply the Legs
Blood reaches the legs through a network of arteries that begin at the heart.
The major arteries involved include:
Aorta
Blood leaves the heart through the aorta, the body’s largest artery.
Iliac Arteries
In the lower abdomen, the aorta divides into the iliac arteries, which carry blood toward each leg.
Femoral Artery
The femoral artery runs through the upper thigh and supplies blood to the muscles of the leg.
Popliteal Artery
Behind the knee, the femoral artery becomes the popliteal artery.
Tibial Arteries
Below the knee, the circulation divides into smaller arteries that travel through the calf.
Pedal and Plantar Arteries
In the foot, small arteries form a network that supplies blood to the toes and skin of the foot.
Many patients with PAD experience a symptom called intermittent claudication.
This refers to muscle pain that occurs during walking and improves with rest.
When you walk, the muscles in your legs need more oxygen to produce energy.
Healthy arteries can increase blood flow during activity.
When arteries are narrowed by plaque, they cannot deliver enough blood to meet the increased demand.
As a result, the muscles temporarily become deprived of oxygen, which causes pain or cramping. Once the person stops walking, the oxygen demand decreases and the pain improves.
Why PAD Causes Pain When Walking
Family History
A family history of cardiovascular disease may increase risk.
Age
PAD becomes more common with increasing age.
High Blood Pressure
High blood pressure places additional stress on artery walls.
Diabetes
Diabetes can damage both large arteries and the smallest blood vessels in the body.
Smoking
Smoking is the strongest risk factor for PAD. Chemicals in tobacco damage the lining of blood vessels and accelerate plaque formation.
High Cholesterol
Elevated cholesterol contributes to plaque formation in arteries.
Arteries That Supply the Legs
Blood reaches the legs through a network of arteries that begin at the heart.
The major arteries involved include:
How PAD Progresses Over Time
Peripheral artery disease develops gradually. Some people may have plaque in their arteries for many years before symptoms appear. In early stages, circulation may still be sufficient for everyday activities. As narrowing progresses, symptoms such as leg pain during walking may develop.
In more advanced cases, circulation may become severely reduced. This can lead to pain in the foot even while resting or wounds that heal slowly because tissues are not receiving enough oxygen. Advanced PAD is sometimes referred to as chronic limb‑threatening ischemia.
Peripheral artery disease is often one manifestation of a broader vascular condition. The same atherosclerosis that narrows arteries in the legs can also affect arteries that supply the heart and brain.
Because of this, people with PAD have an increased risk of heart attack and stroke. For this reason, treatment for PAD focuses not only on improving symptoms in the legs but also on protecting overall cardiovascular health.
Why PAD Is Also a Cardiovascular Disease
