01OverviewDefinition, clinical context and the essential points that orientate the chapter.
Intermittent claudication is exertional aching, cramping, fatigue or heaviness in a lower-limb muscle group caused by demand exceeding flow through a chronically narrowed arterial supply. It is typically reproducible at a similar workload and settles after stopping, without needing a change of posture. Buttock or thigh symptoms suggest aorto-iliac disease, calf symptoms often reflect femoropopliteal disease, and foot symptoms may reflect more distal disease, but symptom location does not map anatomy perfectly.
The consultation has two linked aims. First, determine whether the walking symptom is arterial and whether the limb is stable. Second, recognise PAD as systemic atherosclerotic disease carrying myocardial infarction and stroke risk. Functional limitation, patient priorities and cardiovascular prevention therefore matter even when limb symptoms remain mild. Examination and physiological testing should answer a clinical question; anatomical imaging is reserved mainly for people in whom revascularisation is being considered.
Key points
- Claudication is reproducible exertional muscle discomfort relieved within minutes by rest.
- Ask about distance, terrain, muscle group, recovery, progression and daily-life limitation.
- Sudden symptoms, rest pain, tissue loss or neurological deficit are not stable claudication.
- Examine both legs completely, including skin, temperature, capillary refill, pulses and feet.
- Confirm suspected PAD with correctly performed ABPI and Doppler signal documentation.
- Normal or raised ABPI alone cannot exclude PAD in diabetes or calcified vessels.
- Assess cardiovascular risk, smoking, diabetes, renal disease and coexisting vascular symptoms.
- Revascularisation imaging follows a treatment decision; it is not routine diagnostic screening.
02AetiologyUnderlying causes, associations and risk factors, with why each one matters.
Atherosclerotic narrowing
Smoking, diabetes, hypertension, dyslipidaemia, age and chronic kidney disease promote plaque formation and arterial narrowing, commonly across aorto-iliac, femoropopliteal or infrapopliteal segments.
Less common arterial causes
Popliteal entrapment, cystic adventitial disease, vasculitis, embolic disease, arterial dissection or previous treatment complications can create exertional ischaemia, particularly with atypical age or pattern.
03PathophysiologyThe causal sequence from the underlying abnormality to symptoms and harm.
- 1Limited flow reserve
A stenosed arterial bed may meet resting muscle demand but cannot increase flow adequately during walking, producing reversible metabolic stress and exertional discomfort.
- 2Collateral adaptation
Collateral vessels and skeletal-muscle adaptation alter the workload at which symptoms begin, explaining why anatomical severity and reported walking distance are not perfectly aligned.
- 3Systemic plaque burden
Lower-limb PAD marks atherosclerosis beyond the symptomatic segment, so coronary and cerebrovascular events contribute substantially to long-term morbidity and mortality.
04Clinical features and red flagsSymptoms, examination findings, patterns of presentation and time-critical warnings.
A reproducible ache or cramp begins after walking a similar distance or gradient, affects a muscle group, and resolves within several minutes of standing still.
Record maximum and pain-free walking distance, pace, hills, occupational demands, falls, sleep, independence and which activity the person most wants to regain.
Ask about smoking, diabetes, hypertension, kidney disease, dyslipidaemia, coronary disease, stroke or TIA, erectile dysfunction and previous limb or arterial procedures.
Forefoot rest pain, night pain eased by dependency, ulceration or gangrene signals limb threat rather than uncomplicated claudication.
Abrupt severe pain, coldness, pallor, absent pulses, sensory loss or weakness is an acute vascular emergency even if claudication preceded it.
05InvestigationsWhat to request, why it matters and how to interpret it.
Read from the initial assessment onwards. Tests may run in parallel in urgent care; first-line, preferred, confirmatory, definitive and gold-standard labels appear only when the chapter explicitly states them.
- 01
Ankle-brachial pressure index with Doppler waveformsFirst step - Why
- Confirm a physiological arterial deficit and document baseline lower-limb perfusion.
- Interpretation and limitations
- Measure after supine rest using both brachial pressures and dorsalis pedis and posterior tibial systolic pressures. NICE calculates each leg using the highest ankle pressure divided by the highest arm pressure. A reduced index supports PAD; waveform quality and the clinical picture matter, especially when diabetes, chronic kidney disease or calcification makes ankle vessels poorly compressible.
- 02
Focused cardiovascular risk tests - Why
- Identify modifiable risk and treatment safety factors accompanying established atherosclerotic disease.
- Interpretation and limitations
- Check blood pressure, lipid profile, HbA1c or glucose, renal function and relevant baseline liver tests according to planned therapy. Results guide prevention and medicine safety; they neither prove nor grade the limb lesion.
- 03
Toe pressure or toe-brachial index - Why
- Clarify perfusion when ankle pressures are unreliable or tissue threat is suspected.
- Interpretation and limitations
- Toe vessels may remain compressible when tibial arteries are calcified, but cold, vasospasm and digital disease can distort measurements. Interpret with waveforms, wounds and specialist assessment rather than using a single universal healing cutoff.
- 04
Exercise physiological testing - Why
- Investigate exertional symptoms when resting measurements and clinical suspicion disagree.
- Interpretation and limitations
- A vascular laboratory may repeat ankle pressure and waveforms after a standardised walking protocol. A post-exercise deterioration supports flow-limiting PAD, but protocol and diagnostic thresholds depend on the validated service and the test must not delay urgent referral.
- 05
Duplex arterial ultrasound - Why
- Map disease when revascularisation is being considered after clinical and physiological assessment.
- Interpretation and limitations
- Duplex localises stenosis or occlusion and assesses haemodynamic effect. NICE uses it as first-line anatomical imaging for revascularisation planning; diagnostic curiosity alone is not an indication for serial cross-sectional imaging.
06Differential diagnosisRealistic alternatives and the features that help distinguish them.
Lumbar spinal stenosis
Buttock or leg pain may depend on posture, improve with sitting or flexion, and accompany weakness, numbness or back symptoms rather than a fixed muscle workload.
Musculoskeletal pain
Hip or knee osteoarthritis, tendon disease and compartment syndromes cause movement-specific pain, local tenderness or persistent discomfort that does not reliably resolve after simply standing still.
Venous claudication
Venous outflow obstruction can produce bursting pain, swelling and cyanosis during exercise, often recovering slowly with elevation and accompanied by venous history or signs.
Cardiorespiratory limitation
Breathlessness, angina, arrhythmia or deconditioning may stop walking before arterial symptoms appear and can coexist with objectively confirmed PAD.
Additional chapter-specific clues
Back-related pain, posture-dependent relief, joint-specific pain, venous swelling or breathlessness limiting exercise should widen the differential before attributing symptoms to PAD.
07ManagementImmediate care, first-line treatment, alternatives and escalation.
01Stable assessmentConfirm claudication and define its impactFirst stepChronic exertional leg discomfort resolves with rest and no limb-threat feature is present.+
- 1Characterise onset, reproducibility, muscle distribution, recovery time and the walking activities that symptoms prevent.
- 2Examine cardiovascular status and both lower limbs from groin to toes, comparing skin, temperature, ulcers, capillary refill and femoral, popliteal and pedal pulses.
- 3Perform ABPI with Doppler signal documentation, adding toe or exercise testing when calcification or discordance makes the resting result unreliable.
- 4Explain PAD and address smoking, antiplatelet and lipid therapy, blood pressure, diabetes, foot care and structured exercise while recording a measurable walking goal.
- 5Review functional response; discuss vascular referral when symptoms remain lifestyle limiting despite appropriate non-invasive management or when diagnosis remains uncertain.
02Urgent pathwayEscalate chronic limb threat promptlyEscalationRest pain, ulceration, gangrene or rapidly worsening perfusion suggests chronic limb-threatening ischaemia.+
- 1Document pain, wound extent, infection, pulses, perfusion findings and sensory or motor status without repeatedly testing a threatened foot.
- 2Contact the vascular service urgently and coordinate diabetes, infection and wound management while protecting the foot from pressure and trauma.
- 3Use specialist physiological and anatomical imaging to plan limb salvage, allowing renal function and urgency to determine modality rather than creating serial-test delay.
03Emergency pathwayTreat sudden deterioration as acute ischaemiaAbrupt pain, coldness, pallor, sensory change or weakness develops over hours or days.+
- 1Assess the six ischaemic features, time of onset, rhythm and embolic or thrombosis risks while obtaining immediate senior help.
- 2Discuss immediately with the vascular service, provide analgesia and follow the service anticoagulation pathway unless a contraindication exists.
- 3Do not delay transfer for routine ABPI, outpatient duplex or completion of a chronic claudication work-up.
04Discordant findingsReconsider the diagnosis before escalationEscalationSymptoms, pulses, ABPI and functional limitation do not form a coherent arterial pattern.+
- 1Repeat the history and technically check pressure and waveform acquisition, including both arms and both ankle arteries.
- 2Assess spinal, neurological, hip, knee, venous and cardiorespiratory explanations and recognise that more than one cause may coexist.
- 3Seek vascular-laboratory or specialist review when diabetes, calcification, prior reconstruction or tissue loss makes bedside interpretation unsafe.
08ComplicationsImportant consequences, why they occur and why they matter clinically.
Functional decline
Avoidance of painful walking leads to deconditioning, restricted work and social participation, loss of independence and worsening cardiometabolic health.
Chronic limb threat
Progressive perfusion failure can lead to ischaemic rest pain, ulceration, gangrene, infection and ultimately limb loss, although most stable claudicants do not rapidly reach this stage.
Acute limb ischaemia
Thrombosis on chronic disease or embolism can abruptly threaten tissue viability, producing pain, coldness, sensory loss or weakness that requires emergency assessment.
Cardiovascular events
The systemic atherosclerotic burden increases myocardial infarction, stroke and vascular death risk independently of how troublesome the leg symptom feels.
09Monitoring and follow-upTreatment response, safety checks and longer-term review.
- Record pain-free and maximum walking distance against a personally meaningful activity at baseline and review.
- Recheck feet, skin integrity, pulses and any new rest pain, colour change or non-healing wound.
- Review smoking status, blood pressure, lipids, diabetes control, renal function and adherence to prevention medicines.
- Safety-net explicitly for sudden pain, coldness, sensory loss, weakness, rest pain, ulceration or gangrene.
- After referral or intervention, reconcile antithrombotic therapy and retain surveillance specified by the vascular service.
10Special situationsVariants, exceptions and circumstances that change the usual approach.
Stopping versus posture
Arterial claudication usually settles when exercise stops, whereas lumbar spinal stenosis often improves with sitting or spinal flexion and may permit cycling better than upright walking.
Palpable pulses do not close the case
Proximal pulses can remain palpable with distal disease, embolic blue-toe syndromes or incompressible arteries; integrate the whole examination with physiological evidence.
Diabetes changes confidence
Neuropathy can blunt pain and medial calcification can elevate ankle pressures, so a painless foot or reassuring ABPI must not override tissue loss or abnormal waveforms.
Measure what matters
A treadmill distance can quantify impairment, but treatment success should also reflect the patient’s chosen activity, participation, symptoms and quality of life.
Anatomy follows intent
Detailed arterial mapping becomes useful when revascularisation is genuinely being considered; early imaging without a management question can expose patients to contrast or radiation without changing care.
11Common pitfallsFrequent interpretation and management errors.
- 01
Calling all exercise-related leg pain claudication without checking joint, spinal, neurological and venous patterns.
- 02
Treating a normal or high ABPI as exclusionary in diabetes, renal disease or suspected arterial calcification.
- 03
Missing rest pain, tissue loss or acute neurological deficit because the referral label says claudication.
- 04
Recording pulses only as present or absent without comparing sides, levels, skin and Doppler signals.
- 05
Ordering angiography before establishing whether symptoms justify and the patient would consider revascularisation.
- 06
Focusing on the leg while omitting smoking cessation and secondary cardiovascular prevention.