Atherosclerotic narrowing of peripheral arteries (usually legs) causing reduced blood flow and ischemic pain; diagnosed by an ankle‑brachial index (ABI) <0.90.
Common in older adults and a marker of widespread atherosclerosis – PAD patients have high risk of heart attack and stroke. Can severely limit mobility (claudication pain) and lead to limb loss (amputation) if critical. Early recognition allows risk factor modification to improve survival and quality of life.
Typically an older smoker or diabetic with risk factors. Many cases are asymptomatic, but classic intermittent claudication causes cramping calf or thigh pain after a reproducible walking distance, relieved by rest.
On exam: diminished pulses distal to the obstruction (e.g., weak dorsalis pedis), often with an arterial bruit over narrowed arteries. The limb may have cool, shiny, hairless skin and poor wound healing (arterial ulcers, often on toes or lateral ankle).
In severe PAD, leg pain can occur at rest (especially at night when legs are elevated, relieved by hanging the foot down) and ulcers or gangrene may be present – this indicates critical limb ischemia.
Confirm diagnosis with an ABI test: ABI <0.90 is diagnostic for PAD. If ABI is >1.30 (noncompressible, calcified vessels) or normal despite symptoms, perform an exercise ABI or toe-brachial index for further evaluation.
Gauge severity with classification: e.g., Fontaine Stages I–IV (I asymptomatic; II claudication – IIa mild, IIb severe; III rest pain; IV ulcers/gangrene) or similarly Rutherford grades 0–6. Higher stages (rest pain, tissue loss) indicate critical ischemia.
Manage risk factors aggressively: smoking cessation (most important), exercise, diet, and weight management. Start a high-intensity statin, control blood pressure (often with ACE inhibitor), optimize diabetes control, and use antiplatelet therapy (aspirin or clopidogrel) to reduce CV events.
For claudication, begin supervised exercise therapy (regular walking to improve collateral flow). If lifestyle-limiting pain persists, add cilostazol (PDE-3 inhibitor that improves walking distance; contraindicated in heart failure) for symptom relief.
Condition
Distinguishing Feature
Lumbar spinal stenosis
neurogenic claudication: leg pain with walking/standing, relieved by sitting or flexion; pulses and ABI are normal
Deep vein thrombosis
acute leg pain and swelling, constant (not exercise-induced); leg is often warm and erythematous
Thromboangiitis obliterans
(Buerger disease): young heavy smoker with distal extremity ischemia (digital ulcers/gangrene) from inflammatory thrombosis of small vessels
Lifestyle: vigorous smoking cessation (absolutely essential) and regular exercise (supervised walking programs improve symptoms). Optimize nutrition and weight; manage diabetes and hypertension.
Medical therapy: initiate a high-intensity statin for all PAD patients and an antiplatelet (aspirin or clopidogrel) to reduce cardiovascular events. For claudication pain, cilostazol can improve walking distance (avoid in heart failure).
Revascularization: indicated for critical limb ischemia (rest pain, nonhealing ulcers) or disabling claudication unresponsive to conservative therapy. Options include endovascular angioplasty/stenting (preferred for accessible lesions) or surgical bypass grafting for extensive disease. Amputation is a last resort if revascularization fails.
PAD is essentially "angina of the legs" – exercise-induced muscle pain from ischemia due to arterial narrowing, relieved by rest.
PAD patients have a coronary risk equivalent – their risk of MI or stroke is as high as someone with known coronary disease, so risk factor management is crucial (treat PAD like coronary artery disease in preventive care).
ABI thresholds to know: <0.90 confirms PAD; <0.40 suggests severe ischemia (often with rest pain); >1.30 indicates noncompressible arteries (false normal ABI, common in diabetes – need alternative tests).
Rest pain (foot pain at rest, often nocturnal) or ischemic ulcers/gangrene = critical limb ischemia – requires urgent evaluation by vascular surgery for possible revascularization (to prevent amputation).
Sudden onset of limb pain with pallor, pulselessness, paresthesias, paralysis, and coldness (the "6 P's") suggests an acute limb ischemia (arterial occlusion) – a surgical emergency (immediate heparin and urgent revascularization needed).
Risk factors (age ≥65, smoking, diabetes, etc.) or exertional leg pain → suspect PAD.
Do ankle‑brachial index: ABI <0.90 confirms PAD. If ABI is 0.91–1.30 and symptoms suggest PAD, perform exercise ABI; if ABI >1.30 (calcified vessels), use toe‑brachial index or Doppler ultrasound.
Conservative management for confirmed PAD: smoking cessation, exercise program, statin, blood pressure and glucose control, plus antiplatelet therapy. Add cilostazol if claudication persists and there's no heart failure.
If critical limb ischemia (rest pain, ulcers) or lifestyle-limiting claudication despite optimal medical therapy → proceed to vascular imaging and revascularization (angioplasty/stent vs bypass).
Older male smoker with calf pain after walking a fixed distance (relieved by rest) and weak foot pulses → Peripheral artery disease (intermittent claudication).
Diabetic patient with an ulcer on the toe and foot pain at rest (worse at night, relieved by dangling foot) → Critical limb ischemia from severe PAD.
Middle-aged man with bilateral buttock claudication and erectile dysfunction → Aortoiliac (Leriche) syndrome (PAD at the aortoiliac arteries).
Case 1
A 64‑year‑old man with a 30-year smoking history and hyperlipidemia develops left calf pain after walking about 2 blocks, which subsides within 5 minutes of rest.
Case 2
A 70‑year‑old woman with long-standing diabetes and chronic kidney disease presents with constant right foot pain, even at rest, that worsens when her foot is elevated. She has a non-healing ulcer on her great toe.
Illustration of peripheral artery disease in the legs – left: a normal artery with normal blood flow; right: an artery narrowed by plaque with reduced blood flow.
