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Understanding Peripheral Artery Disease
Peripheral artery disease is plaque narrowing the arteries that carry blood to your legs and feet. It is measured with a simple pressure test called the ankle-brachial index, where 0.90 or below indicates PAD. It progresses through recognizable stages, and the earlier stages are the ones where treatment works best — which is a problem, because the earlier stages are also the quietest.
This article covers what the numbers mean, how the disease moves through its stages, and what is genuinely at stake if it is left alone. For a general overview of symptoms and treatment options, start with our page on peripheral artery disease.
What peripheral artery disease actually is
The same process that narrows the arteries around the heart also happens in the arteries running down the legs. Cholesterol, calcium and inflammatory cells build up inside the artery wall, the channel narrows, and less blood gets through to the muscle and skin downstream.
The National Heart, Lung, and Blood Institute describes PAD as being caused by atherosclerosis, or plaque buildup, that reduces blood flow in the peripheral arteries, and reports that more than 8 million people aged 40 and older in the United States have it. The CDC puts the figure at approximately 6.5 million people aged 40 and over — the two estimates come from different datasets and methods, which is itself a sign of how much of this disease goes uncounted.
The important consequence is that a leg artery problem is rarely only a leg problem. If plaque is narrowing the arteries in your calf, it is usually present elsewhere. NHLBI notes that people with PAD may also have plaque buildup in the arteries leading to and from the heart and brain, which raises the risk of heart attack and stroke.
Why PAD is so easy to miss
The textbook symptom is claudication — a cramping, aching or tired feeling in the calf, thigh or buttock that comes on after walking a predictable distance and settles within a few minutes of stopping. Roughly a quarter of people with PAD have that classic pattern.
Which leaves a great many who do not. According to the CDC, up to 4 in 10 people with PAD have no leg pain at all. Others have symptoms that are real but do not look like the textbook: heaviness, weakness, a leg that simply gives out sooner than it used to. These get attributed to age, arthritis, sciatica or being out of shape, and the circulation is never checked.
There are also signs that show up on the leg itself rather than as pain. The CDC lists muscle weakness, hair loss on the leg, shiny skin, skin that feels cool to the touch, absent pulses in the foot, sores that do not heal, and toes that feel cold or numb.
If you are over 60, or over 50 with diabetes or a history of smoking, the useful question is not "does my leg hurt enough to bother a doctor" — it is "has anyone ever actually measured the blood flow in my legs".
What your ABI number means
The ankle-brachial index is the standard first test, and it is about as simple as medicine gets: a blood pressure cuff and a doppler probe, no needles, no dye, no radiation, roughly fifteen minutes. Blood pressure is measured at the ankle and at the arm, and the ankle figure is divided by the arm figure.
In a healthy leg the two are close, so the ratio sits near 1. When plaque narrows the arteries feeding the leg, ankle pressure drops and the ratio falls with it.
| ABI result | What it indicates |
|---|---|
| Above 1.40 | Arteries too stiff to compress — the number is unreliable and a toe-brachial index or ultrasound is used instead. Common with diabetes or kidney disease. |
| 1.00 – 1.40 | Normal range. |
| 0.91 – 0.99 | Borderline. Often repeated after treadmill walking, which can unmask disease a resting test misses. |
| 0.90 or below | Consistent with peripheral artery disease. |
| 0.40 or below | Severe reduction in blood flow. Usually associated with rest pain or non-healing wounds and warrants prompt specialist assessment. |
Two things about that table are worth holding on to.
The first is that a falsely high number is not a clean bill of health. In long-standing diabetes or kidney disease the artery walls can calcify to the point that a cuff cannot squeeze them shut, which pushes the reading above 1.40 even when the arteries are badly diseased. If your ABI came back high and nobody followed it up, that is worth revisiting.
The second is that a normal resting ABI does not always settle the question. Arteries that cope at rest can fall behind once the muscle demands more blood, so where symptoms strongly suggest PAD, the test may be repeated after exercise.
If the ABI is abnormal, the next step is usually imaging — a vascular ultrasound to see where the narrowing sits and how tight it is.
The stages of peripheral artery disease
PAD is usually described in four clinical stages. The 2024 multi-society PAD guideline — written jointly by the Society for Vascular Surgery, the American Heart Association and the American College of Cardiology among others — organizes care around these presentations: asymptomatic disease, chronic symptomatic disease, chronic limb-threatening ischemia, and acute limb ischemia.
- Asymptomatic. Plaque is present and measurable, but you feel nothing. This is the largest group and the best place to be found, because medication, exercise and stopping smoking do the most good here.
- Claudication. Predictable discomfort with walking that eases with rest. Distance is the thing to track — a walk that used to be comfortable at four blocks and now stops you at one is a change worth reporting, even if the pain itself is mild.
- Chronic limb-threatening ischemia (CLTI). Blood flow is now inadequate even at rest. It shows up as pain in the forefoot or toes at night that is relieved by hanging the foot out of bed, or as a wound, ulcer or area of gangrene that will not heal. This is the stage where the limb itself is at risk and where prompt specialist assessment matters most.
- Acute limb ischemia. A sudden blockage, often from a clot. The leg becomes painful, pale, cold and numb over hours. This is an emergency, not an appointment.
Most people do not march neatly down that list. Many stay in the first two stages for years. But the transition that matters — from "annoying when I walk" to "hurts when I am sitting still, and this sore is not closing" — is the one to act on immediately.
Stroke is a time-critical emergency.
What happens if PAD is not treated
Two separate risks run in parallel, and people tend to only hear about one of them.
The one they hear about is the leg: worsening walking distance, then rest pain, then wounds that will not close, then — at the far end — tissue loss and the possibility of amputation.
The one they usually do not hear about is the rest of the arterial tree. The CDC notes that people with PAD are at increased risk for coronary artery disease and cerebrovascular disease, which can lead to heart attack and stroke. Statistically, that is the bigger threat for most people with PAD. It is also why treatment is never only about the leg — the medication side of PAD care is largely cardiovascular risk reduction.
If you have diabetes, the leg risk carries an extra edge, because reduced sensation means a wound can develop without being felt. We work alongside podiatry and wound care teams on exactly this, and our page on non-healing wounds goes into it in more detail.
What actually helps
Nothing dissolves established plaque. But a great deal changes how much blood reaches the leg, how far you can walk, and how likely you are to have a heart attack — and those are the outcomes that matter.
- Stopping smoking. Nothing else on this list moves the needle as far. Smoking is the strongest modifiable driver of PAD progression and of graft and stent failure after any procedure.
- Structured exercise therapy. Supervised, repeated walking to the point of discomfort. It feels counterintuitive, and it reliably increases walking distance over months.
- Medication. Cholesterol-lowering therapy, blood pressure control, blood sugar control, and antiplatelet therapy, aimed as much at the heart and brain as at the leg.
- Foot care and surveillance. Daily foot checks matter enormously in diabetes, where a small unnoticed injury can become the wound that threatens the limb.
- Restoring flow. When narrowing is severe — particularly at the limb-threatening stage — flow can be restored through the blockage or routed around it, by angioplasty and stenting, atherectomy, or bypass surgery.
Which of these applies depends entirely on stage. Asymptomatic disease is a medication-and-lifestyle problem. Limb-threatening ischemia is a restore-the-blood-flow problem, and a time-sensitive one.
The conversation to have before any amputation
This is the part of PAD care we would most like people to know about in advance.
If an amputation has been raised, the question to ask is direct: has the circulation in this leg been imaged, and has anyone assessed whether blood flow can be restored?
It is a fair question to ask, because the answer is not always yes. A retrospective study of 10,666 Medicare patients with chronic limb-threatening ischemia who underwent a major leg amputation in 2021–2022 found that about one in six had no vascular imaging at all in the six months beforehand, and roughly a third underwent an attempt at restoring blood flow. (This analysis was posted as a preprint in April 2026 and has not yet completed peer review, so treat the precise figures as provisional — but the pattern it describes is consistent with earlier work.)
None of that means every amputation is avoidable. Some are necessary, and sometimes they are the right decision for someone's mobility and quality of life. What it means is that the decision should be made after the circulation has been looked at, not instead of looking. A vascular opinion before an amputation is one of the most valuable second opinions in medicine.
Our limb salvage program exists for this conversation.
Questions worth asking at your appointment
- What is my ABI, and was it done at rest or after walking?
- If my ABI was above 1.40, what was used instead to assess my circulation?
- Which stage does that put me in?
- Is my walking distance expected to improve with exercise and medication, or is a procedure being considered?
- What should make me call sooner rather than wait for the next appointment?
- What is being done about my heart and stroke risk, not just my leg?
If you are unsure whether your symptoms warrant a specialist at all, our guide on when to see a vascular specialist sets out what needs emergency care, what needs an appointment soon, and what can be raised at a routine visit.
Frequently asked questions
An ankle-brachial index (ABI) between 1.00 and 1.40 is generally considered normal. A result of 0.91 to 0.99 is borderline, and 0.90 or below is consistent with peripheral artery disease. Results above 1.40 suggest the arteries are too stiff to compress, which is common in people with diabetes or kidney disease and means the number cannot be read at face value — a toe-brachial index or ultrasound is used instead.
The plaque already in the artery wall does not disappear. What can change is how much blood reaches your leg and how far you can walk. Stopping smoking, structured walking exercise, and medication to control cholesterol, blood pressure and blood sugar can improve symptoms and slow the disease. When a blockage is severe, a procedure can restore flow through or around it. So PAD is treatable and often very manageable, but it is a long-term condition rather than something that is cured once and forgotten.
Two things progress at once. In the leg, reduced blood flow can move from no symptoms, to pain with walking, to pain at rest, to wounds that will not heal — the stage called chronic limb-threatening ischemia, which carries a real risk of amputation. Separately, the same plaque process is usually present in the arteries feeding the heart and brain, so untreated PAD also signals a raised risk of heart attack and stroke. Treating PAD is as much about protecting your heart and brain as your leg.
No, and this is the single most misleading thing about it. The CDC reports that up to 4 in 10 people with PAD have no leg pain at all. Others have symptoms they put down to aging, arthritis or a bad back — tiredness or heaviness in the calf or thigh after walking a certain distance, that eases within a few minutes of standing still. Absence of classic pain is not evidence of healthy arteries.
Walking is one of the most effective treatments there is, even though it is the thing that brings on the discomfort. Structured exercise therapy — walking until the discomfort builds, resting until it eases, then walking again, repeated over a set period several times a week — reliably increases walking distance over months. It should be started with medical guidance, particularly if you have heart disease or a foot wound. Rest pain or an open wound is a different situation and needs to be assessed before starting any exercise program.
For most people it is slow, measured in years, and many remain stable for a long time on medication and exercise. The pace is not fixed, though — continued smoking, uncontrolled diabetes and kidney disease all push it faster. What matters more than the average is the direction of travel in your own case: symptoms that are worsening month to month, pain that appears at rest, or any wound that is not healing all mean the disease has moved to a stage that should be assessed promptly.
Sources
- Centers for Disease Control and Prevention. About Peripheral Arterial Disease (PAD).
- National Heart, Lung, and Blood Institute. Peripheral Artery Disease.
- Gornik HL, Aronow HD, Goodney PP, et al. 2024 ACC/AHA/AACVPR/APMA/ABC/SCAI/SVM/SVN/SVS/SIR/VESS Guideline for the Management of Lower Extremity Peripheral Artery Disease. Circulation. 2024.
- Shah SK, Neal D, Shah KB, et al. Gaps in Vascular Evaluation Before Major Lower-Extremity Amputation Among Medicare Beneficiaries With Chronic Limb-Threatening Ischemia. medRxiv preprint, 2026 — not yet peer reviewed.
This article is general education, not medical advice, and it cannot account for your individual history. Use it to ask better questions of a clinician who can examine you.
Not sure where your circulation stands?
A vascular evaluation is quick, non-invasive, and gives you a clear number to work from rather than a guess. If you have leg symptoms, a wound that will not heal, or risk factors like diabetes or a history of smoking, it is worth knowing.
Call our Largo office to schedule an evaluation, or request an appointment online.