Peripheral Artery Disease — Symptoms, Causes & Treatment | MyMedicPlus

Peripheral artery disease (PAD) refers to atherosclerotic narrowing, stenosis, or occlusion of the peripheral arteries — most commonly the arteries of the lower extremities (aorto-iliac, femoral, popliteal, and tibial vessels) — causing inadequate arterial perfusion to the lower limbs. PAD affects approximately 202 million people globally — around 12% of the adult population — with prevalence increasing steeply with age (3-10% of adults over 50, rising to 20% over 80 years). PAD is not merely a limb disease but a systemic manifestation of atherosclerosis affecting the entire arterial tree: patients with PAD have a 3-4 times higher risk of myocardial infarction and a 2-3 times higher risk of ischaemic stroke than age-matched individuals without PAD, reflecting concurrent coronary artery disease and cerebrovascular disease. Despite this, up to 40% of PAD patients are asymptomatic at the time of diagnosis (detected by low ankle-brachial index on screening), contributing substantially to the overall atherosclerotic disease burden. PAD encompasses a clinical spectrum from intermittent claudication (reproducible exertional leg pain from muscle ischaemia) through to chronic limb-threatening ischaemia (CLTI — formerly called critical limb ischaemia), which represents the most severe end: rest pain, non-healing ulcers, and gangrene. CLTI carries a 1-year major amputation risk of 25-40% and a 1-year mortality of 20-25% without revascularisation.

Atherosclerosis is the underlying pathological process in over 90% of PAD cases — the same lipid plaque deposition, foam cell accumulation, smooth muscle migration, and fibrous cap formation that drives coronary and cerebrovascular disease. Risk factors for PAD parallel those for atherosclerotic cardiovascular disease: smoking (the single strongest independent modifiable risk factor for PAD — 4x increased risk; 90% of patients with intermittent claudication are or were smokers; smoking causes premature atherosclerosis in lower limb arteries); diabetes mellitus (doubles PAD risk and dramatically increases amputation risk — diabetic PAD tends to be more distal, affecting tibial and peroneal arteries, and is often asymptomatic due to concurrent peripheral neuropathy until advanced ischaemia is present); hypertension (3x increased PAD risk); hypercholesterolaemia (each 1 mmol/L reduction in LDL reduces cardiovascular events including PAD progression by 20-25%); age above 50 (PAD prevalence doubles per decade); male sex (though sex disparity narrows after the menopause); chronic kidney disease (independent risk factor via accelerated vascular calcification); and obesity (increases all metabolic risk factors). Non-atherosclerotic causes include thromboangiitis obliterans (Buerger's disease — inflammatory occlusive disease of small and medium vessels in young male heavy smokers, associated with distal ischaemia, superficial thrombophlebitis, and Raynaud's phenomenon — requires complete tobacco cessation as the only effective treatment); systemic vasculitides; and arterial thromboembolism from cardiac sources or aortic pathology.

Intermittent claudication (IC) is the hallmark symptom of PAD affecting 30-40% of PAD patients — a reproducible, predictable, cramping or aching pain or fatigue affecting muscle groups distal to the diseased arterial segment, arising on walking a consistent distance and characteristically resolving within 2-10 minutes of rest (distinguishing it from neurogenic claudication from spinal stenosis, which requires sitting down and takes longer to resolve). Anatomical location of stenosis determines claudication distribution: aorto-iliac disease causes buttock and thigh claudication (Leriche syndrome: bilateral buttock claudication, absent femoral pulses, and erectile dysfunction in men from external iliac disease); femoral-popliteal disease causes calf claudication (most common). Approximately 40% of PAD patients are entirely asymptomatic — identified only by ABI measurement; 30-40% have typical claudication; and 1-2% per year progress to chronic limb-threatening ischaemia (CLTI). Chronic limb-threatening ischaemia (CLTI) — the most severe manifestation: rest pain (burning pain in the foot and toes, worse at night from loss of hydrostatic perfusion when supine — relieved by hanging the leg down or sleeping in a chair); ischaemic ulcers (punched-out, painful, on pressure points — heel, between toes, tips of toes — with poor granulation tissue and no surrounding cellulitis compared to venous ulcers); and gangrene (dry — black, mummified; or wet — infected, with systemic sepsis). Clinical signs: absent or reduced femoral, popliteal, or foot pulses; dependent rubor (red discoloration of the foot when dependent, pallor on elevation — Buerger's test); skin atrophy; hair loss; thickened nails; and cool extremities with delayed capillary refill above 3 seconds. Diabetic PAD frequently lacks claudication due to coexisting neuropathy, presenting directly with painless foot ulcers or gangrene.

Ankle-brachial index (ABI): the cornerstone non-invasive screening and diagnostic test for PAD — measured with a handheld Doppler probe comparing ankle systolic blood pressure (posterior tibial artery or dorsalis pedis artery) to the higher of the two brachial pressures; ABI above 0.9 to 1.3 is normal; 0.7-0.9 mild PAD (often asymptomatic); 0.5-0.7 moderate PAD (claudication); below 0.5 severe PAD (CLI); above 1.4 indicates calcified incompressible arteries (diabetes, CKD — falsely elevated, requires toe-brachial index [TBI] instead). Toe-brachial index (TBI): measures the systolic blood pressure at the big toe (using a digital cuff and photoplethysmography) — normal TBI above 0.7; TBI below 0.7 confirms PAD in diabetic patients where ABI is unreliable due to medial calcinosis. Duplex ultrasound: combined B-mode ultrasound and Doppler flow velocity waveform assessment — identifies the anatomical location and haemodynamic severity (PSV ratio above 2.5 indicates significant stenosis above 50%) of peripheral arterial disease along the entire limb arterial tree; safe, no contrast, no radiation. CT angiography (CTA): three-dimensional arterial roadmap from aorta to pedal vessels using iodinated contrast — essential planning tool before revascularisation to determine occlusion length, calcification, and target vessel quality. MR angiography (MRA): avoids radiation and iodinated contrast; excellent detail of tibio-peroneal vessels; preferred in patients with eGFR above 30 (gadolinium caution below 30 for nephrogenic systemic fibrosis). Invasive digital subtraction angiography (DSA): performed at the time of planned endovascular treatment — simultaneously diagnostic and therapeutic. Post-exercise ABI: ABI measured immediately after treadmill walking to claudication — a significant fall (above 0.15 reduction) confirms haemodynamically significant PAD when resting ABI is borderline (0.9-1.0).

PAD management comprises cardiovascular risk factor modification, symptom management (supervised exercise therapy), and revascularisation for limb-threatening disease or disabling claudication. Cardiovascular risk factor modification (mandatory for all PAD patients): smoking cessation — the single most impactful intervention, reducing cardiovascular events, slowing PAD progression, and halving amputation risk; high-intensity statin therapy (atorvastatin 40-80mg or rosuvastatin 20-40mg daily) reduces major adverse cardiovascular events by 25-30% and is recommended for all PAD patients regardless of cholesterol level (ESC/AHA guideline — LDL target below 1.4 mmol/L in PAD); antiplatelet therapy (clopidogrel 75mg daily is preferred over aspirin in PAD per CAPRIE trial showing 23% relative risk reduction; low-dose rivaroxaban 2.5mg twice daily plus aspirin 100mg [COMPASS trial] reduces major adverse limb events by 31% and all-cause mortality by 18% in stable atherosclerotic disease including PAD); ACE inhibitors or ARBs for hypertension (ramipril also improves walking distance); optimal glycaemic control in diabetes (HbA1c target per local guidelines — aggressive control reduces microvascular and amputation risk). Supervised exercise therapy: the most effective non-interventional treatment for intermittent claudication — 30-45 minutes of treadmill exercise to near-maximal claudication pain threshold, 3x weekly for 12 weeks (NICE-recommended, minimum 3 months), improving pain-free walking distance by 100-200% through collateral vessel formation, muscle oxygen extraction improvement, and haemorrheological changes; superior to home walking advice or endovascular treatment alone for claudication quality of life. Endovascular revascularisation (interventional radiology): balloon angioplasty with drug-eluting stent (DES) placement for focal iliac and superficial femoral artery stenoses/occlusions — preferred for TASC A and B lesions; atherectomy for calcified lesions. Surgical bypass: aorto-femoral bypass for aorto-iliac occlusive disease; femoral-popliteal bypass (saphenous vein graft preferred, synthetic PTFE for below-knee bypass) for femoral-popliteal disease — TASC C and D lesions and failure of endovascular approaches. CLTI: urgent multidisciplinary vascular team assessment for revascularisation strategy or planned amputation when revascularisation is not feasible.

Chronic limb-threatening ischaemia (CLTI) and major amputation: without revascularisation, CLTI carries a 25-40% risk of major amputation (above-knee or below-knee amputation) within 1 year; 1-year mortality in CLTI patients is 20-25% from the high concurrent cardiovascular burden. Diabetic PAD is particularly aggressive and insidious: the combination of peripheral arterial disease and diabetic neuropathy means pain sensation is blunted — patients often present with painless foot ulcers or gangrene without prior claudication symptoms, leading to very late presentation; diabetic foot ulcers progress rapidly to deep infection and osteomyelitis without appropriate early intervention. Major adverse cardiovascular events (MACE): PAD patients have a 3-4x higher annual risk of MI and stroke than age-matched controls without PAD — cardiovascular events (not limb ischaemia) account for the majority of PAD-related mortality; overall 5-year cardiovascular mortality in symptomatic PAD is 15-30%. Acute limb ischaemia (ALI): sudden complete arterial occlusion from thrombus or embolism (cardiac source, aneurysm) superimposed on chronic PAD causes the '6 Ps' emergency (Pain, Pallor, Pulselessness, Paraesthesia, Paralysis, Poikilothermia) — a vascular emergency with a 4-6 hour window for revascularisation before irreversible limb necrosis. Post-surgical wound healing complications are particularly common in PAD patients undergoing bypass surgery — poor distal perfusion impairs tissue healing; diabetic patients have additional microvascular and immune compromise increasing wound infection and dehiscence risk.

Primary prevention: smoking cessation is the most powerful preventive measure for PAD — lifelong non-smokers have substantially lower PAD risk, and cessation at any stage reduces disease progression; treatment with varenicline, nicotine replacement therapy, and bupropion combined with behavioural support achieves 30-40% 12-month abstinence rates. Cardiovascular risk factor control from early adulthood (lipid management, blood pressure control, glycaemic management in diabetes) prevents or delays atherosclerotic disease across all arterial beds. Population-level ABI screening is recommended for: all patients over 50 with any atherosclerotic risk factor; all diabetic patients over 40; all patients with known coronary or cerebrovascular disease; and patients over 70 regardless of risk factors. Daily foot inspection in diabetic patients with known PAD or neuropathy: examination for new blisters, ulcers, pressure sores, and colour changes — early detection and prompt wound care prevents infected foot ulcers from progressing to limb-threatening ischaemia. Regular walking (even at the level of inducing claudication then resting) builds lower limb arterial collateral network, improving perfusion and delaying symptom progression. Antiplatelet therapy and statins in high-risk primary prevention populations reduce incident PAD as well as coronary and cerebrovascular events.

Call emergency services (999/911) immediately for: sudden onset of one or more of the '6 Ps' in a limb — Pain (sudden severe), Pallor (limb becomes pale or white), Pulselessness, Paraesthesia (pins and needles), Paralysis (inability to move), and Poikilothermia (limb cold to touch) — this is acute limb ischaemia, a vascular emergency requiring revascularisation within 4-6 hours to save the limb; sudden worsening of rest pain in known PAD — may indicate acute-on-chronic ischaemia from thrombus; a non-healing foot ulcer or dark discoloration (gangrene) of toes or foot — critical limb ischaemia requiring same-day vascular surgery assessment. See your GP urgently for: calf pain (or thigh, buttock) that reliably comes on with walking and resolves with 2-5 minutes rest — claudication — requires ABI measurement and cardiovascular risk assessment; a new foot ulcer or wound that is not healing in a diabetic patient — infection risk is high, and ischaemia must be excluded; cold, pale, or blue foot in a diabetic patient — may indicate advanced PAD even without claudication due to diabetic neuropathy masking pain. Do not wait: diabetic foot complications with PAD deteriorate rapidly — early vascular assessment prevents major amputation.