Heart & Cardiometabolic HealthVascular & Arterial Disease
Peripheral Artery Disease (PAD): Symptoms, Ankle-Brachial Index (ABI), and Walking Therapy
Peripheral artery disease (PAD) causes exertional leg cramping (claudication), cold limbs and slow healing ulcers. It occurs due to atherosclerosis causing stenosis of the arteries in the lower limbs. This article will review diagnostic criteria (ABI measurements), antiplatelet therapy and supervised exercise.
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Written by Dr. Naresh Trehan, MBBS, MD, FACSChairman & Chief Cardiac Surgeon, Medanta – The Medicity
Medically Reviewed by Dr. Rommel Tickoo, MBBS, MD✓ Verified
Published: 2026-09-03Reviewed: October 2026Updated: 2026-11-03T10:49:53.134Z 10 min read 1620 Views
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Quick Summary & Key Findings
PAD is caused by plaque build up that causes reduced blood flow through the arteries of the legs. Classic symptoms consist of intermittent claudication: pain or cramps in the calves/thighs when walking that subside on rest within a few minutes. A diagnosis can be made from a ABI ≤0.90. Treatment options include: supervised walking exercise, high dose statins, antiplatelets (aspirin or clopidogrel) and blood pressure control.
Peripheral artery disease (PAD) affects over 200 million people worldwide and is a key marker for widespread atherosclerosis. Cholesterol laden plaques cause narrowing of the inner walls of the iliac, femoral, popliteal and tibial arteries.
PAD is often ignored. Pain, cramping or heaviness in the legs on exertion can be dismissed as being a normal part of ageing or joint arthritis. If the narrowing isn’t treated it can lead to more severe problems including critical limb ischemia, foot ulcers and a higher risk of a cardiac infarction and ischemic stroke.
If patients realise the difference between vascular claudication and musculoskeletal pain they can have quick, non-invasive vascular tests performed. This will then start patients on lifestyle and drug treatments to improve mobility and cardiovascular health.
Recognizing Intermittent Claudication and Vascular Red Flags
The classic symptom of PAD is intermittent claudication. During ambulation, there is increased requirement of oxygen to the muscles of the calf, thigh or buttock. This cannot be supplied due to narrowing of the arteries causing pain in muscles due to lack of blood supply (ischemia).
Reproducible exertional cramping: Onset of pain occurs after a fixed distance of walking. Pain is aggravated by walking uphill or increasing speed. Pain subsides within 2-5min of standing stationary.
Coolness and pallor on elevation: The affected foot is often cool to palpation and pale on elevation; there is dependent rubour (reddish purple discolouration) if the foot is hanging free.
Hair Loss and Shiny Skin Reduced micro vascular supply makes skin on legs thin, toenails brittle and hair growth on your shins and toes poor.
Diminished Peripheral Pulses: Weak or absent dorsalis pedis and posterior tibial pulses on palpation.
Rest Pain (Critical Limb Ischemia) Severe burning pain in the toes/forefoot causing the patient to wake at night. Relieved by dangling the foot over the edge of the bed.
Ankle-Brachial Index (ABI) and Diagnostic Workup
The most common non-invasive screening test for PAD is the Ankle Brachial Index (ABI) which uses a handheld Doppler probe to compare the systolic pressure at the ankles to the systolic pressure in the upper arm.
Normal ABI (1.00 – 1.40): Indicates open, healthy arterial flow.
Borderline ABI (0.91 – 0.99): Suggests early vascular disease, warranting exercise treadmill testing.
Mild to Moderate PAD (0.41 – 0.90): Confirms hemodynamic arterial obstruction causing exertional claudication.
Severe PAD (≤0.40): Indicates severe ischemia with elevated risk of tissue loss and non-healing ulcers.
Non-Compressible ABI (>1.40): Reflects calcified, rigid arterial walls (common in long-standing diabetes and renal disease), requiring toe-brachial index (TBI) testing.
Supervised Walking Therapy: Mechanisms and Protocol
Structured walking exercise is a first line treatment for PAD. Many trials have shown that it is comparable to endovascular stent intervention in improving pain free walking distances.
Collateral vessel formation Angiogenesis is induced by repetitive episodes of transient ischemia. This leads to formation of new microvascular shunts around blocked arteries.
Endothelial Nitric Oxide Release: Regular exercise improves vasodilation of blood vessels, reducing arterial stiffness.
Walk on a treadmill/track at a moderate pace until you are experiencing claudication pain which is of moderate severity (grade 3 out of 4). Stop walking and rest until your pain has completely stopped. Repeat this 3-5 times a week for 30-45 minutes.
Pharmacological support – Cilostazol (100mg twice daily) can be prescribed to inhibit the phosphodiesterase-3 enzyme which will cause vasodilation and increase walking distance.
Atherosclerotic Lower-Extremity Hypoperfusion, The ABI Index & The COMPASS Trial
Peripheral Artery Disease is caused by the development of systemic atherosclerosis leading to gradual narrowing of arteries in the infra-renal aorta, iliac, femoropopliteal and infrapopliteal tibial vessels. During walking there is an increase in the metabolic demand for oxygen in the working calf muscles (gastrocnemius and soleus). This increases beyond a fixed supply of oxygen, causing intermittent claudication. Symptoms resolve when the patient stands still for 5-10 minutes. PAD is a definitive sign of systemic atherosclerosis. Patients with PAD of the lower limbs are three times more likely to have a myocardial infarction, stroke and die from cardiovascular disease within 10 years compared to age matched controls.
Ankle Brachial Index (ABI) – normal (1.00 to 1.40), borderline (0.91 to 0.99), abnormal PAD (≤0.90), severe limb ischaemia (≤0.40). If ABI > 1.40 then there is non-compressible calcified medial arteries. Common in diabetes and late CKD. This needs secondary testing with the Toe Brachial Index (TBI). Abnormal if ≤0.70.
COMPASS Randomized Trial: In a landmark trial of dual pathway inhibition (low dose rivaroxaban (2.5mg x2/day) + Aspirin (100mg/day)) has demonstrated a 24% reduction in MACE and 46% reduction in MALE events (including major amputations) compared to aspirin mono-therapy (NEJM n=27,395).
Supervised Exercise Therapy (SET) Recommendations: According to ACC/AHA guidelines, supervised exercise therapy (30-45 mins intermittent treadmill walking to cause moderate claudication pain, 3x weekly or more for at least 12 weeks) should be provided in a hospital or clinic setting (Class I recommendation). This provides an improvement in pain free walking distance of 120-180% as it causes increase in collateral vessel formation and improves mitochondrial efficiency in skeletal muscle.
Pharmacological relief of claudication: Cilostazol (100mg twice daily) is a selective PDE3 inhibitor with antiplatelet and vasodilator properties. This drug can greatly increase maximum walking distance, however it is absolutely contraindicated in patients with any degree of heart failure (NYHA class I-IV).
Critical Limb-Threatening Ischemia (CLTI), The WIfI System & Revascularization
PAD can progress into Critical Limb-Threatening Ischemia (CLTI) if there is inadequate arterial perfusion to meet the metabolic demand of the resting tissues. The symptoms of CLTI include severe rest pain at night in the distal forefoot (often alleviated by hanging the leg over the edge of the bed), non-healing ulcers on the skin caused by ischemia and gangrene. If a patient does not receive timely angiography to identify the area of ischemia and have their arteries revascularized, 25% will require major limb amputation within 12 months.
The SVS WIfI classification system is based on 3 objective measures of risk of amputation. These are wound depth (W: 0-3), degree of ischemia (ankle pressure or transcutaneous oximetry TcPO2) (I: 0-3) and severity of foot infection (fI: 0-3).
Endovascular Balloon Angioplasty and Stenting is the preferred treatment of choice for focal aortoiliac and superficial femoral artery (SFA) disease (TASC II Class A-C). Drug coating balloons (DCB) and drug eluting stents (DES) are used to prevent smooth muscle cell proliferation.
Surgical infrainguinal bypass- The randomized trial BEST-CLI (NEJM 2022) has demonstrated that surgical femoral popliteal or femoral tibial bypass procedures offer significantly reduced rates of major re-intervention and amputation when compared to endovascular options in patients with sufficient autologous great saphenous vein (GSV) conduit.
Comprehensive Medical Secondary Prevention All patients with PAD should be treated with high intensity statins (atorvastatin 80mg or rosuvastatin 40mg to reach target LDL-C <55 mg/dL). Blood pressure should be optimised (<130/80mmHg) using ACEi/ARB. Smoking cessation should be achieved using two agents (varenicline or bupropion plus NRT).
Duplex Ultrasound Waveform Velocity, TBI in Diabetes & The Walking Ladder Protocol
Color duplex ultrasound provides real time B-mode imaging combined with spectral pulsed wave Doppler techniques. This allows anatomical localization and hemodynamic grading of arterial stenosis in the aortoiliac, femoropopliteal, and infrapopliteal circulation. The normal peripheral arteries of the lower extremity demonstrate a high resistance multiphasic waveform with a high velocity systolic upstroke, small early diastolic retrograde flow, and late diastolic elastic rebound.
Peak Systolic Velocity Ratio (PSVR) is determined by dividing the maximum systolic velocity (PSV) in a focal stenotic jet by that of the proximal normal artery. A ratio of ≥2.0 indicates ≥50% lumen stenosis. A ratio of ≥3.0 indicates high grade >75% diameter stenosis.
Toe Brachial Index (TBI) in Medial Calcinosis: Patients with longstanding diabetes/end stage renal disease can develop calcified Mönckeberg's medial sclerosis in the muscular layer of the tibial and dorsalis pedis arteries. This leads to a hard and incompressible vessel giving a falsely raised ABI (>1.40). Digital artery calcification is uncommon so TBI <= 0.70 is an absolute diagnosis.
Gardner-Skinner Progressive Treadmill Protocol A validated clinical walking test involving a constant speed of 2.0mph with an incrementing slope of 2% every 2 minutes. Initial Claudication Distance (ICD) is the distance walked until the patient begins to feel calf pain. Absolute Claudication Distance (ACD) measures the maximum distance walked.
Careful preventive measures are required. Daily inspection of web spaces between toes. Trimming of nails by a podiatrist. Use inserts specifically designed for your feet to reduce the pressure on the metatarsal bones. Avoid using heat pads or hot soaks which can cause burns without you being aware of it due to lack of feeling in the feet.
Diagnostic Modalities: Lower-Extremity Vascular Perfusion Assessments
| Vascular Modality | Measurement Parameter | Normal Physiological Value | PAD Ischemic Diagnostic Threshold | Clinical Utility & Limitations |
|---|---|---|---|---|
| Ankle-Brachial Index (ABI) | Ratio of highest ankle systolic pressure to highest brachial systolic pressure | 1.00 – 1.40 | <=0.90 (Mild: 0.71–0.90, Moderate: 0.41–0.70, Severe: <=0.40) | Universal first-line screening tool; false-negative (falsely normal or >1.40) in calcified, non-compressible arteries in diabetic/dialysis patients. |
| Toe-Brachial Index (TBI) | Ratio of digital great toe systolic pressure (via photoplethysmography cuff) to brachial pressure | 0.70 – 0.85 | <=0.70 (Absolute toe pressure <30 mmHg indicates severe critical limb ischemia) | Preferred alternative to ABI in diabetes and CKD; digital arteries are immune to Mönckeberg's medial calcinosis. |
| Color Duplex Ultrasonography | Peak Systolic Velocity Ratio (PSVR) and spectral Doppler waveform velocity profile | Triphasic high-resistance flow pattern with PSVR <1.5 | PSVR >=2.0 indicates >=50% stenosis; monophasic dampening indicates proximal occlusion | Non-invasive anatomical mapping; zero radiation and zero nephrotoxic contrast; operator dependent in distal tibial vessels. |
| Computed Tomography Angiography (CTA) | Multi-detector 3D helical arterial luminal contrast opacification | Smooth, uninterrupted contrast flow throughout femoropopliteal and infrapopliteal tree | Direct visualization of calcified and non-calcified plaque stenosis, occlusion length, and collaterals | Rapid pre-procedural revascularization roadmap; requires iodinated contrast (caution in CKD) and dense calcium can cause blooming artifacts. |
| Transcutaneous Oximetry (TcPO2) | Measures partial pressure of oxygen diffusing through heated skin sensor to forefoot | >50 mmHg at room air | <30 mmHg reflects severe tissue hypoxia; <20 mmHg indicates failure of spontaneous wound healing | Crucial objective prognostic tool for predicting ischemic ulcer healing and determining viable amputation levels. |
Frequently Asked Questions
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Clinical Reviewer License Verified
Dr. Rommel Tickoo, MBBS, MD
Director, Internal Medicine & Infectious Diseases, Max Super Speciality Hospital, Saket • MBBS, MD (Internal Medicine)Dr. Rommel Tickoo is the Director of Internal Medicine at Max Super Speciality Hospital, Saket, New Delhi. With over 24 years of experience in adult primary care, infectious disease management, routine screenings, and fever diagnostics, he reviews mediguide4u preventive care and vaccination protocols.
License ID: DMC-12876
Director, Department of Internal Medicine, Max Super Speciality Hospital, Saket, New Delhi
Medically evaluated on October 2026View Dr. Profile, Verified Credentials & Articles
References & Clinical Resources
- Clinical Research Faculty & Editorial Team. AHA/ACC Guideline on the Management of Patients with Lower Extremity Peripheral Artery Disease (2020-2026). [Access Resource Link] — Journal of the American College of Cardiology
- Clinical Research Faculty & Editorial Team. Supervised Exercise Training for Peripheral Artery Disease (2020-2026). [Access Resource Link] — Cochrane Database of Systematic Reviews
- Clinical Research Faculty & Editorial Team. Global Vascular Guidelines on the Management of Chronic Limb-Threatening Ischemia (2020-2026). [Access Resource Link] — Journal of Vascular Surgery
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5.0 out of 5 (2 reviews)
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Marcus T., Cardiology PatientVerified Patient
•August 18, 2026
This guide broke down the exact diagnostic thresholds and medication pathways so clearly. My cardiologist recently discussed adjusting my regimen, and reading this helped me prepare specific questions for my follow-up visit.
Dr. Ashok Seth, MBBS, MD, FRCP, FACCInterventional Cardiologist & Medical Reviewer
Thank you for sharing, Marcus. Preparing targeted questions beforehand makes clinical consultations far more productive. Always discuss any dosage or timing adjustments directly with your attending physician.
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Patricia L., Nurse PractitionerHealthcare Professional
•August 29, 2026
The structured comparison tables and ACC/AHA clinical trial references are outstanding. I frequently print sections of this guide to explain lifestyle modifications to patients in our outpatient clinic.
Dr. Ashok Seth, MBBS, MD, FRCP, FACCInterventional Cardiologist & Medical Reviewer
We are honored to support your clinical practice, Patricia. Translating complex cardiovascular guidelines into patient-friendly education is the core mission of our editorial board.