Peripheral artery disease (PAD) is a condition where narrowed arteries reduce blood flow to your limbs, most commonly the legs. Over 113 million people worldwide have PAD, and the number is rising. It develops gradually, often goes unnoticed for years, and carries serious risks beyond just leg pain, including significantly higher chances of heart attack and stroke.
How PAD Develops in Your Arteries
PAD starts with damage to the inner lining of your arteries. Fatty deposits, cholesterol, and other substances build up in the artery wall, forming what’s called plaque. Over time, these fatty deposits become oxidized and trapped beneath the artery’s inner surface, where they trigger inflammation and attract immune cells. Those immune cells absorb the fat and swell into “foam cells,” which enlarge the plaque further and narrow the artery’s opening.
The process isn’t limited to plaque buildup alone. Calcium deposits can form in the middle layer of the artery wall, making arteries stiff and less able to expand with each heartbeat. In some cases, particularly in the arteries below the knee, blood clots account for much of the blockage even when plaque buildup is minimal. This means PAD involves more than just cholesterol clogging a pipe. It’s a combination of inflammation, clotting, and structural changes to the artery wall itself.
Who Is Most at Risk
Smoking and diabetes are the two strongest risk factors. In a large national survey, smoking carried the highest odds of developing PAD (about 4.5 times greater risk), followed by diabetes (about 2.7 times greater risk). People with diabetes have PAD rates ranging from 20% to 50%, compared to 10% to 26% in people without diabetes. High blood pressure and high cholesterol follow as the next major contributors.
Age matters too. PAD becomes far more common after 50, and rates climb steeply with each decade. In North America, the prevalence rate is roughly three times the global average, likely reflecting higher rates of obesity, diabetes, and sedentary lifestyles.
What PAD Feels Like
The hallmark symptom is called claudication: muscle pain or cramping in your legs that starts when you walk and stops when you rest. The calf is the most common location, but you might feel it in your thigh, buttock, or foot, depending on where the artery is narrowed. Some people describe it more as heaviness or fatigue than sharp pain. It’s predictable: the same walking distance tends to trigger it each time, and a few minutes of standing still lets it fade.
As the disease progresses, that distance shrinks. You might initially feel pain after walking several blocks, then eventually after crossing a single room. In advanced stages, the pain appears even at rest, particularly in your feet. Rest pain is often worse at night when you’re lying flat, because gravity is no longer helping blood reach your feet. Hanging your leg off the side of the bed or getting up to walk briefly can provide temporary relief.
Many people with PAD have no symptoms at all, particularly in the early stages. The arteries may be significantly narrowed before blood flow drops enough to cause noticeable problems.
Stages of the Disease
Doctors classify PAD severity using a staging system that maps closely to what you experience:
- Stage I: No symptoms. Arteries are partially blocked but blood flow is still adequate.
- Stage II: Claudication appears. In milder cases, pain starts only after walking more than about 200 meters (roughly two city blocks). In more limiting cases, pain starts before that distance.
- Stage III: Pain at rest, especially in the feet. Blood flow is now severely restricted even without physical activity.
- Stage IV: Tissue damage. Skin sores that won’t heal, or tissue death visible as darkened or blackened skin on the foot or toes.
Stage III and IV together represent what’s called chronic limb-threatening ischemia, the most dangerous form of PAD. Symptoms are present for more than two weeks, and the risk of losing the limb becomes very real. Up to 1 in 3 people with this condition need a major amputation (above the ankle) within one year of diagnosis.
How It’s Diagnosed
The primary screening test is the ankle-brachial index, or ABI. It compares the blood pressure measured at your ankle to the blood pressure in your arm. In a healthy person, these numbers are roughly equal, giving a ratio near 1.0. A ratio between 0.41 and 0.90 indicates mild to moderate PAD. A ratio of 0.40 or below signals severe disease. The test is painless, takes about 10 to 15 minutes, and uses standard blood pressure cuffs.
If the ABI is abnormal or your symptoms suggest PAD, imaging tests can pinpoint where and how badly the arteries are blocked, which helps guide treatment decisions.
The Heart Attack and Stroke Connection
PAD in your legs is a warning sign that atherosclerosis is likely happening throughout your body, including in the arteries feeding your heart and brain. People with symptomatic PAD have a 70% higher risk of cardiovascular events (heart attack, stroke, or heart failure) and an 80% higher risk of death compared to people without PAD, even after accounting for other risk factors. This is why treatment for PAD isn’t just about your legs. It’s about protecting your entire cardiovascular system.
Exercise as Treatment
Structured walking programs are one of the most effective treatments for claudication, and they work in a counterintuitive way: you walk until the pain appears, then rest until it fades, then walk again. This repeated cycle trains your body to develop alternative blood flow pathways and use oxygen more efficiently in your leg muscles.
The standard supervised program involves three sessions per week, each lasting 30 to 60 minutes, for at least 12 weeks. During each session, you walk on a treadmill at a speed and incline that brings on claudication pain within a few minutes. When the pain reaches a moderate level, you stop and sit until it completely subsides, then start again. The total session time includes both walking and resting periods. Over weeks, most people find they can walk significantly farther before pain starts.
Supervised programs (in a clinic or rehab facility with trained staff) consistently outperform unsupervised home walking. The structure, monitoring, and progressive adjustments make a measurable difference in outcomes.
Medications for PAD
The 2024 guidelines from the American College of Cardiology and the American Heart Association recommend a combination of therapies to prevent both cardiovascular events and limb complications. The core medications include an antiplatelet drug (typically a single blood thinner like low-dose aspirin) to prevent clots, a high-intensity cholesterol-lowering medication, and blood pressure management. For people with diabetes, tight blood sugar control is essential. Smoking cessation isn’t optional; it’s the single most impactful lifestyle change.
For patients who aren’t at high risk of bleeding, a combination of low-dose aspirin with a low-dose blood thinner has been shown to reduce both cardiovascular events and serious limb complications beyond what aspirin alone achieves.
Procedures to Restore Blood Flow
When medications and exercise aren’t enough, or when limb-threatening ischemia develops, procedures to physically reopen or bypass the blocked artery become necessary. There are two main approaches.
Endovascular procedures are minimally invasive. A catheter is threaded through a small puncture (usually in the groin) to the blocked area, where a balloon is inflated to widen the artery, often with a stent left in place to keep it open. Recovery is fast, sometimes same-day, with minimal downtime. In studies comparing this approach to open surgery for severe leg ischemia, there was no significant difference in outcomes for the first two years.
Open bypass surgery reroutes blood around the blocked section using either a vein from your own body or a synthetic graft. It’s a larger operation requiring more recovery time, but it tends to hold up better over the long term. When a patient’s own vein is used, bypass grafts in the leg maintain blood flow about 70% to 75% of the time at five years, with roughly 80% of threatened limbs saved. For blockages higher up, near the hip and pelvis, bypass patency rates reach 80% to 95% at five years.
After the two-year mark, studies show that patients who had bypass surgery using their own vein had better survival and lower amputation rates than those who had balloon procedures alone. The choice between the two depends on where the blockage is, how extensive it is, and whether you’re healthy enough for a larger surgery.