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Occlusive Arterial Disease - Surgical Overview

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Definition & Classification

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I. CHRONIC OCCLUSIVE ARTERIAL DISEASE

Etiology (Das)

• Atherosclerosis (most common - chronic)
• Embolism (acute)

• Buerger's disease (thromboangiitis obliterans)
• Raynaud's disease
• Diabetes mellitus
• Scleroderma
• Physical agents: trauma, radiation, electric burns, pressure necrosis

Symptoms

• The classic symptom: muscle pain (cramp-like) due to accumulation of P-substance from inadequate blood flow during exercise
• Location of pain depends on level of arterial occlusion:
  • Foot - Buerger's disease (tibial/plantar artery occlusion)
  • Calf - Femoropopliteal junction occlusion (most common)
  • Thigh - Occlusion at opening of superficial femoral artery
  • Buttock - Bifurcation of common iliac artery or aorta
• Boyd's Classification of claudication:
  • Grade I - Pain disappears as patient continues walking
  • Grade II - Pain continues but patient can still walk with effort
  • Grade III - Pain compels the patient to rest

• Continuous, aching pain - "the cry of the dying nerves"
• Due to ischaemic changes in somatic nerves
• Worse at night
• Aggravated by elevation of leg above heart level
• Relieved by hanging the leg in a dependent position
• Affects most distal parts first (tips of toes)

Leriche Syndrome (Bailey & Love)

• Claudication in the buttocks, thighs and calves
• Absent femoral and distal pulses bilaterally
• Impotence (due to loss of internal iliac flow)
• Bruit over the aortoiliac region

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II. ACUTE ARTERIAL OCCLUSION

Causes (Das)

1. Arterial Embolus (most common)
2. Trauma
3. Acute Arterial Thrombosis

Arterial Embolus

• Cardioarterial embolisation (majority): due to atrial fibrillation, mitral stenosis, or myocardial infarction
• Arterioarterial embolisation: from ulcerated atherosclerotic plaque

1. Bifurcation of common femoral artery
2. Bifurcation of popliteal artery
3. Bifurcation of common iliac artery
4. Bifurcation of aorta

Classic Clinical Features - The 6 P's (Das)

1. Pain
2. Pallor (waxy/cadaveric pallor, then cyanosis within 1 hour)
3. Paraesthesia
4. Paralysis
5. Pulselessness
6. Perishing cold (temperature change)

Neurological symptoms carry prognostic value - if motor and sensory functions are intact, the extremity will survive

Arterial Trauma Causing Acute Occlusion (Das)

• Penetrating wounds disrupting arterial wall
• Pressure on artery by angulated bone
• Intimal rupture from fracture/dislocation
• Injury by bone fragment

• Supracondylar fracture of humerus
• Supracondylar fracture of femur
• Dislocated shoulder or elbow
• Dislocated knee

Acute Arterial Thrombosis

• Most common site: lower end of femoral artery at the subsartorial canal/popliteal space junction
• Often occurs in an artery already narrowed by arterial disease
• Acute-on-chronic: acute ischaemia develops on pre-existing chronic occlusion

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III. GANGRENE - Types (Das)

1. Change of colour (pale → bluish-purple → black)
2. Loss of temperature
3. Loss of sensation
4. Loss of pulsation
5. Loss of function

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IV. INVESTIGATIONS

Clinical Site-Disease Correlation (Bailey & Love)

Non-invasive Investigations

• Normal resting ABI: 0.9 - 1.4
• < 0.9 = haemodynamically significant arterial lesion
• < 0.4 = suggests Chronic Limb-Threatening Ischaemia (CLTI)
• Drop > 20% after exercise = flow-limiting disease

• 1.4 (falsely elevated) = vessel incompressibility, typically in diabetes mellitus

• A post-exercise drop of >20% in ABI is diagnostic

• Normal artery = triphasic signal
• Diseased artery = biphasic or monophasic signal

• Oscillometry - detects arterial pulsation at different levels; in embolism, sudden needle decrease at the level of obstruction
• Plethysmography - measures blood flow; segmental plethysmography with cuffs at thigh, calf, ankle
• Vasospasm assessment (sympathectomy suitability) - nerve block with local anaesthetic; Brown's Vasomotor Index: operation advisable only when index ≥ 3.5
• Blood lipids, glucose tolerance test

Imaging (Bailey & Love)

• DSA (Digital Subtraction Angiography): Gold standard; Seldinger technique via common femoral artery; complications in ~5% (haematoma, thrombosis, distal embolisation, renal dysfunction)
• CT Angiography (CTA): Rapid; unaffected by calcification
• MRA: No radiation; limited by pacemakers, metallic implants; gadolinium can cause nephrogenic systemic fibrosis in renal dysfunction

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V. MANAGEMENT

Non-Surgical / Conservative (Bailey & Love)

• Exercise: Structured programme ≥2 hours/week for 3 months + smoking cessation - sustained improvement in claudication distance
• Statin: Stabilises atherosclerotic plaques; reduces cardiac death independent of lipid levels
• Antiplatelet therapy:
  • Clopidogrel 75 mg/day (first choice per global guidelines)
  • Aspirin 75 mg/day (alternative)
• Risk factor modification: DM control, weight loss, hypertension management, lipid control

Only 1 in 4 patients with intermittent claudication deteriorate during their lifetime; <5% require amputation over 5 years

Endovascular Treatment

• Balloon catheter inserted via Seldinger technique under local anaesthesia
• Guidewire crosses stenosis/occlusion under fluoroscopic control
• Balloon inflated at high pressure for ~30 seconds
• Very successful for iliac and femoropopliteal segments; results below the knee are less successful
• Subintimal angioplasty for long occlusions (guidewire crosses lesion in the subintimal space, new lumen created)
• Stenting if vessel fails to stay adequately dilated
• Complications ~5%: failure, haematoma, bleeding, thrombosis, distal embolisation

Surgical Treatment (Bailey & Love)

• Aortoiliac reconstruction: 90% at 5 years
• Femoropopliteal vein bypass: ~60% at 5 years
• PTFE femoropopliteal bypass: <50% at 5 years

• Most useful in early Buerger's disease or Raynaud's disease when vasospasm predominates
• Once organic changes have developed, sympathectomy is of limited value
• Brown's Vasomotor Index ≥ 3.5 = operation advisable

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VI. ACUTE ARTERIAL OCCLUSION - Management (Das)

1. Embolectomy - Fogarty catheter embolectomy via arteriotomy (gold standard for acute embolism)
2. Anticoagulation - Heparin immediately to prevent propagation of thrombus
3. Thrombolysis - For acute thrombosis
4. Surgical revascularisation - If embolectomy fails or thrombosis superimposed on chronic disease
5. Amputation - When irreversible ischaemia has occurred (paralysis + anaesthesia = poor prognosis)
   • Oscillometry guides level: if no pulsation in the leg → amputation through thigh; if oscillation present in leg → lower amputation

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Summary Flowchart

Occlusive Arterial Disease
├── Acute
│   ├── Embolism → Heparin + Fogarty Embolectomy
│   ├── Trauma → Vascular repair
│   └── Acute Thrombosis → Thrombolysis / bypass
└── Chronic
    ├── Claudication only
    │   └── Exercise + Risk factor modification + Antiplatelet
    ├── Claudication not responding → PTA ± Stenting
    └── CLTI (rest pain / tissue loss)
        ├── Endovascular (PTA/stenting)
        └── Open surgery (Bypass / Endarterectomy)
            └── Unsalvageable limb → Amputation

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• S. Das - A Manual on Clinical Surgery, 13th Edition, pp. 85-101
• Bailey & Love's Short Practice of Surgery, 28th Edition, pp. 1022-1029
• Mulholland & Greenfield's Surgery, 7th Edition (infrainguinal occlusive disease)
• Schwartz's Principles of Surgery, 11th Edition (lower extremity occlusive disease)