Peripheral Arterial Disease
Peripheral arterial disease (PAD) is narrowing or blockage of the arteries that supply blood to the limbs—most often the legs—usually due to atherosclerosis. PAD is a common condition that often goes unrecognized; it ranges from silent disease found on imaging to leg pain with walking (claudication), non-healing wounds, and, in severe cases, critical limb ischemia. PAD is also a marker of widespread atherosclerosis and increases the risk of heart attack, stroke, and other cardiovascular events. Ankle-brachial index testing, ultrasound, CT angiography, and MR angiography are the main tools used to identify and characterize PAD.
What is it?
Peripheral arterial disease, often called PAD, is a condition in which the arteries supplying blood to parts of the body outside the heart and brain—most commonly the legs—become narrowed or blocked. The most common underlying cause is atherosclerosis, the same process that causes coronary artery disease. Cholesterol-rich plaque builds up in the artery walls over time, narrowing the channel through which blood flows and reducing the supply of oxygen and nutrients to the tissues downstream. When demand for blood increases—such as during walking or other exertion—the affected limb may not receive enough blood, leading to pain or other symptoms.
PAD affects different parts of the arterial tree. The aortoiliac segment (the lower aorta and arteries in the pelvis), the femoral arteries (in the thighs), the popliteal arteries (behind the knees), and the smaller arteries below the knee (such as the tibial and peroneal arteries) can all be involved. Patients with diabetes often have particularly significant disease in the smaller arteries below the knee. PAD can also affect arteries supplying the arms (subclavian and other upper-extremity arteries), although this is less common.
Major risk factors for PAD include smoking (which is one of the strongest contributors), diabetes, high blood pressure, high cholesterol, older age, chronic kidney disease, obesity, and a family history of cardiovascular disease. Other contributors include certain inflammatory conditions, prior radiation, and rare hereditary or vasculitic conditions. PAD often coexists with disease in other arterial territories—including the coronary arteries (causing coronary artery disease) and the arteries to the brain (causing carotid artery disease and increased stroke risk)—and is itself an important marker of overall cardiovascular risk.
Symptoms vary widely. Many people with mild or moderate PAD have no symptoms or only minor changes that they may not attribute to circulation problems. The classic symptom is intermittent claudication—pain, cramping, aching, or fatigue in the calves, thighs, or buttocks that occurs predictably with walking, improves quickly with rest, and recurs on similar activity. Other symptoms can include reduced exercise tolerance, cold or pale feet, hair loss on the legs, slow-healing wounds, weak or absent pulses on examination, or pain at rest in advanced disease. Critical limb ischemia—the most severe form of PAD—is associated with rest pain, non-healing wounds, ulcers, and gangrene, and represents a serious threat to the limb. Acute limb ischemia, in which blood supply to a limb is suddenly cut off (such as by a clot from the heart or another artery), is a medical emergency that requires immediate evaluation.
Evaluation typically begins with a careful history, examination of the legs and pulses, and ankle-brachial index (ABI) testing—a simple, noninvasive measurement comparing blood pressures at the ankle and arm. A low ABI suggests PAD, while a high ABI may indicate non-compressible arteries (often seen in diabetes or kidney disease). Arterial ultrasound provides detailed information about specific segments of the arteries and is widely used. CT angiography (CTA) and MR angiography (MRA) produce detailed three-dimensional images of the arteries and are particularly useful for planning interventions. Invasive angiography is typically used when endovascular treatment is anticipated or when noninvasive imaging is inconclusive. Toe pressures and transcutaneous oxygen measurements may be helpful when there is wound healing concern or non-compressible arteries.
Important to Know
Management of PAD is highly individualized and combines aggressive risk factor management with treatment of leg symptoms or limb-threatening disease. Because PAD is also a strong marker of overall cardiovascular risk, treatment focuses both on improving leg circulation and on preventing heart attack and stroke.
Smoking cessation is the single most important step for smokers and significantly improves outcomes. Other foundational measures include regular physical activity (particularly structured walking programs and supervised exercise therapy for claudication), a heart-healthy diet, weight management, treatment of sleep apnea, limited alcohol, and stress reduction.
Medications play a central role. Statins and other lipid-lowering therapies are typically recommended to reduce LDL cholesterol, stabilize plaque, and lower cardiovascular event risk. Antiplatelet therapy (such as aspirin or clopidogrel) is generally recommended in symptomatic PAD. A specific anticoagulant–antiplatelet combination (low-dose rivaroxaban plus aspirin) has been shown to further reduce cardiovascular and limb events in selected patients with PAD. Blood pressure control and diabetes management (often including newer agents with cardiovascular benefit such as SGLT2 inhibitors and GLP-1 receptor agonists when appropriate) are important. Medications specifically aimed at improving walking distance, such as cilostazol, can help selected patients with claudication.
For patients with limb-threatening ischemia—including critical limb ischemia or significant symptoms despite optimal medical and exercise therapy—revascularization is often needed. Endovascular treatments use catheters, balloons, stents, and other devices to open narrowed arteries. Surgical bypass operations create new pathways around blocked segments using veins or synthetic grafts. Treatment plans depend on the location and pattern of disease, overall health, anatomy, and patient preferences. Wound care, foot care, and infection management are essential parts of treatment for patients with ulcers or tissue loss.
Acute limb ischemia is a medical emergency. Rapid evaluation and treatment—often with anticoagulation, catheter-directed therapies, or surgery—are essential to save the limb and minimize damage.
Care is typically coordinated by primary care clinicians, cardiologists, vascular medicine specialists, vascular and endovascular surgeons, interventional radiologists, wound care specialists, podiatrists, and other relevant providers. Imaging findings are interpreted alongside symptoms, examination, and other test results.
Even when PAD is mild and asymptomatic, identifying it provides an opportunity for aggressive risk factor management that can substantially reduce future cardiovascular events. Patient education about foot care, exercise, smoking cessation, and recognition of warning signs is an important part of long-term care.
Red flag symptoms include sudden severe leg pain with coolness, paleness, numbness, or weakness (which may indicate acute limb ischemia); non-healing wounds or ulcers on the feet or legs; signs of infection of the feet or legs; foot pain at rest, especially at night; severe chest pain or shortness of breath; signs of stroke; or signs of shock. These warrant prompt or urgent medical evaluation.