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This is a clinician-written, evidence-based summary aligned to the 2026 MLA Content Map. It is intended for medical students and junior doctors preparing for the UKMLA. Always cross-reference with NICE guidance, local protocols, and clinical judgement.
The Bottom Line
- PAD = atherosclerotic disease of limb arteries. Affects ~20% of people over 60. Shares risk factors with coronary and cerebrovascular disease
- Intermittent claudication: cramping leg pain on walking, relieved by rest. Critical limb ischaemia: rest pain, ulceration, or gangrene
- ABPI ≤0.9 confirms diagnosis. ABPI 0.5–0.9 = claudication. ABPI <0.5 = critical ischaemia
- First-line for claudication: supervised exercise programme (NICE CG147) + CVD risk factor modification + antiplatelet + statin
- Critical limb ischaemia: urgent vascular referral for revascularisation (angioplasty/bypass) — risk of amputation
Overview
Peripheral arterial disease (PAD) is an atherosclerotic occlusive disease of the arteries supplying the limbs, most commonly affecting the superficial femoral artery. It exists on a clinical spectrum from asymptomatic disease (detected by reduced ABPI) through intermittent claudication (predictable exercise-induced leg pain) to critical limb ischaemia (rest pain, ulceration, gangrene). PAD is a marker of systemic atherosclerosis — patients have a 3-fold increased risk of MI and 4-fold increased risk of stroke. NICE CG147 guides diagnosis and management.
Epidemiology
PAD affects approximately 20% of people over 60 years in the UK, though many are asymptomatic. Prevalence increases steeply with age. Smoking is the single most important modifiable risk factor (3–4 fold increased risk). Other risk factors include diabetes (increases risk of amputation), hypertension, hyperlipidaemia, and CKD. Only about 25% of patients with claudication will deteriorate; most remain stable. However, 5-year mortality in PAD patients is 30% (from cardiovascular events, not from limb loss).
Clinical Features
Symptoms
Intermittent claudication: cramping pain in calf, thigh, or buttock on walking a reproducible distance, relieved by rest within minutes
Leriche syndrome: buttock claudication + erectile dysfunction + absent femoral pulses (aortoiliac disease)
Rest pain: constant burning pain in foot/toes, worse at night, relieved by hanging leg over bed edge
Non-healing ulcers or wounds on feet/toes
Gangrene (dry or wet)
Cold feet, numbness
Signs
Absent or diminished peripheral pulses (femoral, popliteal, dorsalis pedis, posterior tibial)
Arterial bruits (femoral, iliac)
Cool, pale limb (especially on elevation — Buerger test positive: pallor on elevation, reactive hyperaemia on dependency)
Hair loss, shiny skin, thickened nails on affected limb
Punched-out, painful ulcers on toes, heel, or pressure points (arterial ulcers)
Capillary refill time prolonged (>3 seconds)
Gangrene of toes or forefoot
Investigations
First-line
Ankle-brachial pressure index (ABPI)Normal: 1.0–1.3. ≤0.9 = PAD confirmed. 0.5–0.9 = claudication range. <0.5 = critical ischaemia. >1.3 = vessel calcification (unreliable, common in diabetes)
BloodsHbA1c, lipid profile, FBC, U&Es, coagulation (pre-operative)
Second-line
Duplex ultrasoundFirst-line imaging — localises and grades stenosis, assesses flow
Exercise ABPIIf resting ABPI is normal but clinical suspicion remains — may fall significantly with exercise
Specialist
CT angiographyPre-operative planning for revascularisation — shows anatomy of entire arterial tree
MR angiographyAlternative to CT if renal function poor (no iodinated contrast)
Digital subtraction angiographyGold standard but invasive; usually combined with intervention (angioplasty ± stenting)
1
All PAD patients — CVD risk reduction
- Smoking cessation (single most effective intervention)
- Statin: atorvastatin 80 mg OD
- Antiplatelet: clopidogrel 75 mg OD (preferred per NICE) or aspirin 75 mg
- BP control per NICE NG136; HbA1c optimisation in diabetes
2
Intermittent claudication
- Supervised exercise programme: 2 hours per week for 3 months (first-line per NICE)
- Naftidrofuryl oxalate 200 mg TDS — consider if exercise programme not effective or unsuitable (only vasoactive drug recommended by NICE)
- Angioplasty ± stenting only if exercise programme fails and symptoms are lifestyle-limiting
3
Critical limb ischaemia (CLI)
- Urgent vascular referral — within 24 hours
- Revascularisation: angioplasty ± stenting or surgical bypass
- Wound care and infection management
- Amputation if revascularisation not possible and tissue loss is extensive
4
Acute limb ischaemia (6 Ps)
- Emergency vascular referral — Pain, Pallor, Pulselessness, Paraesthesia, Paralysis, Perishingly cold
- IV heparin to prevent clot propagation
- Embolectomy or thrombolysis within 6 hours to avoid irreversible tissue loss
Complications
- Critical limb ischaemia: Rest pain, gangrene, amputation
- Acute limb ischaemia: Thrombosis on existing stenosis or embolism — limb-threatening emergency
- Cardiovascular events: MI, stroke (leading cause of death in PAD patients)
- Amputation: Major limb amputation required in ~5% of claudicants over 5 years
- Infected foot ulcers: Especially in diabetic patients — risk of osteomyelitis and sepsis
UKMLA Exam Tips
- 1ABPI ≤0.9 = PAD; <0.5 = critical ischaemia; >1.3 = calcified vessels (common in diabetes — unreliable result)
- 2Supervised exercise is first-line for claudication — NOT immediate revascularisation
- 3Naftidrofuryl is the only vasoactive drug NICE recommends for claudication
- 4Clopidogrel (not aspirin) is the preferred antiplatelet for PAD per NICE
- 5Acute limb ischaemia = the 6 Ps — requires emergency revascularisation within 6 hours
- 6Arterial ulcers are painful, punched-out, on pressure points — contrast with venous ulcers (shallow, irregular, medial malleolus, in gaiter area)
- 7PAD patients die of MI and stroke, not limb loss — always address systemic CVD risk
practicetest your knowledge on peripheral arterial diseaseApply what you've learnt with UKMLA-style questions from the iatroX Q-Bank — cardiovascular and beyond.
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