Chronic Lower Limb Ischaemia: Intermittent Claudication

Notes

Disease

Vascular Surgery

Overview

Chronic lower limb ischemia can be classified using the Fontaine classification:

I – asymptomatic
II – intermittent claudication
III – rest pain
IV – ulcers/gangrene

Grades III and IV are classified as Critical Limb Ischemia.

Intermittent claudication is a type of chronic lower limb ischemia that presents with muscle pain on exercise and is relieved on rest². It affects 4% of people over 55, mostly men¹. Up to 60% of patients have an underlying coronary or carotid disease. Around 40% experience stroke within 5 years of presentation³.

Definition

Peripheral artery disease (PAD) is a chronic obstruction of arteries supplying the extremities, usually caused by atherosclerosis; it is more common in the lower limb.
Intermittent claudication (IC) is defined by leg muscle pain, cramping and fatigue brought on by exercise; relieved on rest and caused by inadequate blood supply; it is the primary symptom of peripheral arterial disease (PAD).
Critical limb ischemia is a severe form of chronic lower limb ischemia, which presents with tissue wounds like ulcers and gangrene, and rest pain worse at night and relieved by hanging the limb dependent.
Acute limb ischemia is defined by a rapid drop in arterial blood flow resulting in cessation of nutrient and oxygen delivery to the tissues.

Anatomy / Physiology

Most common sites involved are femoral and popliteal arteries³

Parent Artery	Major Branches
Abdominal Aorta	Common Iliac Arteries
Common Iliac Artery	External Iliac Artery
Common Iliac Artery	Internal Iliac Artery
External Iliac Artery	Femoral Artery
Femoral Artery	Deep Femoral Artery
Femoral Artery	Superficial Femoral Artery
Deep Femoral Artery	Medial Femoral Circumflex Artery
Deep Femoral Artery	Lateral Femoral Circumflex Artery
Superficial Femoral Artery	Popliteal Artery
Popliteal Artery	Anterior Tibial Artery
Popliteal Artery	Posterior Tibial Artery
Posterior Tibial Artery	Fibular (Peroneal) Artery
	Medial Plantar Artery
	Lateral Plantar Artery
Anterior Tibial Artery	Dorsalis Pedis Artery
Dorsalis Pedis Artery	Arcuate Artery
Dorsalis Pedis Artery	First Metatarsal Artery
Arcuate Artery	Second, Third and Fourth Metatarsal Arteries

Aetiology and Risk Factors

Aetiology

Atherosclerosis (most common)
Buerger’s disease (Thromboangiitis obliterans)
Popliteal artery entrapment syndrome

Buerger’s disease is acute inflammation and clotting of arteries and veins in hands and feet; it can lead to blockages and cause ischemia.
Popliteal artery entrapment syndrome is defined as compression of popliteal artery by surrounding muscles, particularly during exercise.

Risk Factors

Smoking
Hyperlipidemia
Diabetes
Hypertension
Family history

Pathophysiology

Atherosclerosis in the peripheral arteries of legs leads to an inadequate blood supply due to narrowing or hardening of the arteries. During exercise, increased oxygen demand leads muscles to operate anaerobically, producing lactic acid and other metabolites, which further lead to leg pain, aching, cramping or numbness in the calf, buttock, hip, thigh or arch of the foot. Lactic acid and other metabolites get washed away on rest, but the condition reiterates on further exercising.³

Clinical Manifestation

Cramp-like pain in a muscle group (usually calf, thigh, or buttock) triggered by exertion (e.g. walking) and relieved by rest.
Pain consistently occurs after walking a specific distance
Relieved within minutes of stopping activity.
Location of pain localises disease level:
- Calf claudication (most common) → femoropopliteal disease.
- Thigh claudication → superficial femoral or common femoral disease.
- Buttock/hip claudication ± impotence → aortoiliac disease (Leriche syndrome).

Remember

Erectile dysfunction → think aortoiliac disease (Leriche syndrome).

Examination

Arterial pulses: weak or absent pulses distally to diseased artery
Skin changes: dryness, thinning, or hair loss, and possibly signs of poor circulation such as slow-healing wounds.
Buerger’s test positive: pallor on elevation, rubor on dependency.

Differential diagnosis

Venous claudication → pain with prolonged standing, relieved by elevation or walking.-
Neurogenic claudication (spinal stenosis) → pain with standing, relief on sitting or leaning forward (shopping trolley sign), variable distance.
Nerve root entrapment: entrapment of the sciatica can cause radiculopathy down to calve muscles
Baker’s cyst: A fluid filled growth that forms behind the knee causing swelling, tightness or discomfort, particularly on knee movement; it can burst and cause pain

Chronic compartment syndrome: increase in pressure in a closed muscle compartment during activity leading to compression of blood vessels and nerves, causing swelling, tightness and pain.

Investigations

Ankle-brachial Pressure Index (ABPI)

Less than 0.9 in presence of appropriate history is diagnostic
Exercise ABPI may show a post exercise significant decrease in ABPI coinciding with pain

Segmental blood pressure (measured at various points along the limb to help localise disease)

A drop >20-30 mmHg between adjacent cuffs suggests significant arterial obstruction between those two levels.
The site of greatest pressure drop indicates the location of significant stenosis or occlusion

Imaging:

Only for intervention planning: duplex US, CT or MR angiogram, digital subtraction angiogram
Abdominal ultrasound to rule our aneurysm

Diagnostic approach to Intermittent Claudication²

ABPI (Ankle-brachial Pressure Index) is used to assess blood flow in legs. It is calculated by dividing the systolic blood pressure at the ankle by the systolic blood pressure at the arm (brachial artery). ABPI values:1.0 – 1.4 – normal0.9 to 0.5 – intermittent claudication<0.5 – critical limb ischemia>1.4 – calcified vessels.

Treatment

Risk factor modification is first-line:

Stop smoking
Oral statin
Supervised exercise program
Control BP and glucose
Antiplatelet therapy (aspirin or clopidogrel)

Endovascular treatment:

Angioplasty + stent
- Mostly done in aorto-iliac segment or superficial femoral
- Not in popliteal and tibial due to high risk of occlusion
- Useful in short stenoses/occlusions

Surgery:

Bypass graft or endarterectomy
- Used for short distance claudication, severe lifestyle limitation, failure of endovascular treatment in aorto-iliac segment
- Commonly used for long stenoses/occlusions

Statins are drugs used to lower blood cholesterol and prevent progression of atherosclerosis. Mechanism of action: inhibit the enzyme HMG-CoA reductase, which is used to make cholesterol. They are used to reduce risk of heart attack, stroke and other ischemia. Side effects: myalgia (muscle pain) is most common, it can lead to rhabdomyolysis (breakdown of muscle fibers). Examples: rosuvastatin and atorvastatin.

Angioplasty is a procedure used to dilate narrow arteries. A catheter is placed in the vessel and a balloon is inflated at the point of narrowing causing the vessel lumen to dilate. A stent is often left in place to prevent recurrent narrowing.
Endarterectomy is a surgical procedure used to remove an atheroma (fatty buildup inside an artery). An incision is made in the arterial wall and the atheroma is removed; the vessel wall is then stitched back together. This procedure is used to prevent complications like stroke and limb ischemia.
Aspirin as an antiplatelet inhibits the COX-1 enzymes, reducing synthesis of thromboxane A2, which results in decreased platelet aggregation and reduced risk of thrombus formation. Aspirin can also be used to relieve pain, reduce inflammation and lower temperature. Side effects: gastrointestinal irritation, bleeding.

Complications and Prognosis

Complications

Progression to critical limb ischemia
Higher risk of atherosclerotic morbidity – stroke and coronary artery disease
Myalgia (side effect of statins)
Bleeding (side effect of aspirin and clopidogrel)

Remember

Critical limb ischemia is defined as grade III and IV chronic lower limb ischemia, while intermittent claudication is grade II.

Prognosis

One third of patients improve, one third remain stable, one third deteriorate
4% require an intervention and 2% result in amputation¹

References

Peripheral vascular disease. In: McLatchie G, Borley N, Agarwal A, Jeyarajah S, Harries R, Weerakkody R, et al., editors. Oxford Handbook of Clinical Surgery: Oxford University Press; 2022. p. 0. https://doi.org/10.1093/med/9780198799481.003.0019
Beard JD. Chronic lower limb ischemia. West J Med. 2000;173(1):60-3. doi: 10.1136/ewjm.173.1. https://pmc.ncbi.nlm.nih.gov/articles/PMC1070983/
Meru AV, Mittra S, Thyagarajan B, Chugh A. Intermittent claudication: An overview. Atherosclerosis. 2006;187(2):221-37. https://doi.org/10.1016/j.atherosclerosis.2005.11.027
Mohamad Yusoff F, Kajikawa M, Sakamoto T, Tanaka A, Higashi Y. Low-intensity pulsed ultrasound for ‘no-option’ chronic/critical limb-threatening ischaemia in a patient with Buerger disease: a case report. European Heart Journal – Case Reports. 2024;8(6). https://doi.org/10.1093/ehjcr/ytae246
Obara H, Gupta PC, Levien L, Mistry P, Bollineni V, Shaw PM. A short review of popliteal artery entrapment syndrome. JVS-Vascular Insights: An Open Access Publication from the Society for Vascular Surgery. 2025;3. https://doi.org/10.1016/j.jvsvi.2025.100186
Mizzi A, Cassar K, Bowen C, Formosa C. The progression rate of peripheral arterial disease in patients with intermittent claudication: a systematic review. Journal of Foot and Ankle Research. 2019;12(1):40. https://doi.org/10.1186/s13047-019-0351-0