Peripheral Artery Disease

Peripheral Artery Disease (PAD) is a manifestation of systemic Atherosclerosis

Aetiology

Primary Cause

Atherosclerotic plaque formation → luminal narrowing

Less Common Cause

  • Thromboembolism
  • Vasculitis
  • Thromboangiitis Obliterans
  • Fibromuscular dysplasia

Pathophysiology

Atherosclerotic Progression
  1. Endothelial dysfunction
  1. Lipid deposition (LDL oxidation)
  1. Inflammation → plaque formation
  1. Progressive luminal narrowing
Ischemia Mechanism
  • Rest: adequate perfusion
  • Exercise: ↑ demand → ischemia → claudication
Advanced Disease
  • Critical perfusion ↓ → rest pain, ulcer, gangrene
Common Sites
  • Aortoiliac (buttock claudication)
  • Femoropopliteal (calf claudication — most common)
  • Tibial vessels (critical limb ischemia)

Epidemiology

  • Prevalence:
    • ~3–10% general population
    • 20% in elderly (>70 years)
  • Strongly associated with:
    • Coronary Artery Disease
    • Cerebrovascular disease

Risk Factors

Major
  • Smoking
  • Diabetes mellitus
  • Hypertension
  • Dyslipidemia
  • Obesity
Non-Modifiable
  • Age >50
  • Male sex
  • Family history
  • Sedentary lifestyle
 

Clinical Presentation

Asymptomatic Stage
  • Many patients are asymptomatic
  • Reduced perfusion detected only by:
    • ↓ pulses
    • Abnormal ABI
Important: asymptomatic PAD still carries high cardiovascular risk
 
Intermittent Claudication (Classic Presentation)
  • Exercise-induced muscle pain
  • Relieved by rest (within minutes)
  • Cramping, tightness, fatigue
  • Reproducible at a fixed walking distance
Special Syndrome
  • Leriche syndrome (aortoiliac disease):
    • Buttock claudication
    • Erectile dysfunction
    • Absent femoral pulses
Pain Location → Level of Lesion
Location of Pain
Likely Arterial Disease
Buttock/hip
Aortoiliac
Thigh
Femoral
Calf (most common)
Femoropopliteal
Foot
Tibial/peroneal
Critical Limb Ischemia (Advanced PAD)
Rest Pain
  • Persistent pain (especially at night)
  • Localized to:
    • Toes
    • Forefoot
  • Relieved by hanging leg off bed (gravity improves perfusion)
Tissue Loss
  • Non-healing ulcers
  • Gangrene
Ulcer Characteristics
  • Painful
  • Located at:
    • Toes
    • Pressure points
  • “Punched-out” appearance
Acute Limb Ischemia (Emergency)
“6 Ps”
  1. Pain
  1. Pallor
  1. Pulselessness
  1. Paresthesia
  1. Paralysis
  1. Poikilothermia
Indicates sudden arterial occlusion. Typically <2 weeks onset
Physical Examination Findings
Inspection
Skin Changes
  • Pale (ischemia)
  • Dependent rubor (red when limb lowered)
  • Shiny, thin skin
  • Hair loss
  • Muscle atrophy
Special Tests
Buerger’s Test
  • Elevation → pallor
  • Dependency → reactive hyperemia (rubor)
Palpation
  • Cool extremity
  • CRT delayed (>2 seconds)
  • Diminished or absent pulses:
    • Femoral
    • Popliteal
    • Dorsalis pedis
    • Posterior tibial
Buerger’s Test / Buerger Sign
Buerger’s Test / Buerger Sign
Classification
Fontaine
Rutherford
Clinical Meaning
I
0
Asymptomatic
IIa
1
Mild claudication (walking distance >200 m)
IIb
2–3
Moderate–severe claudication (walking distance <200 m)
III
4
Rest pain
IV
5–6
Tissue loss (ulcer/gangrene)
Clinical Interpretations
A. Claudication Phase
  • Fontaine II / Rutherford 1–3
  • Indicates exercise-induced ischemia
  • Managed initially with:
    • Lifestyle modification
    • Medical therapy
B. Critical Limb Ischemia (CLI)
  • Fontaine III–IV / Rutherford 4–6
  • Features:
    • Rest pain
    • Ulcers
    • Gangrene
→ Requires urgent evaluation for revascularization

Investigations

Bedside / First-Line Tests
Ankle–Brachial Index (ABI) — Key Screening Test
Principle
Ratio of ankle systolic pressure to brachial systolic pressure.
notion image
notion image
Interpretation
ABI
Interpretation
1.0–1.4
Normal
0.91–0.99
Borderline
<0.90
Diagnostic of PAD
<0.40
Severe ischemia
>1.40
Non-compressible (calcified vessels, e.g., diabetes)
 
 
Toe-Brachial Index (TBI)
  • Used when ABI is unreliable (e.g., diabetes, CKD)
  • Detects distal ischemia
Non-Invasive Vascular Imaging
Doppler Ultrasound
Findings
  • Site of stenosis
  • Flow velocity changes
  • Turbulence distal to lesion
Utility
  • First-line imaging
  • No radiation
Segmental Pressure Measurement
  • Identifies level of obstruction
  • Pressure drop between segments → stenosis site
Pulse Volume Recording (PVR)
  • Assesses limb perfusion via waveform analysis
  • Blunted waveform = arterial disease
Advanced Imaging (Anatomical Assessment)
CT Angiography (CTA)
  • High-resolution arterial imaging
  • Defines:
    • Stenosis
    • Occlusion
  • Useful for intervention planning
MR Angiography (MRA)
  • Alternative to CTA
  • No ionizing radiation
 
Digital Subtraction Angiography (DSA) — Gold Standard
Features
  • Highest spatial resolution
  • Allows simultaneous intervention (angioplasty/stenting)
Indications
  • Severe disease
  • Prior to revascularization

Management

Core Principle
  • Reduce cardiovascular risk (systemic atherosclerosis)
  • Relieve symptoms (claudication)
  • Prevent limb loss (critical ischemia)
Lifestyle Modification (Foundation)
  • Smoking cessation (most important)
  • Supervised exercise therapy (30–45 min, ≥3×/week)
  • Weight reduction, healthy diet
Pharmacotherapy
Disease-Modifying (Mandatory)
  • Antiplatelet: Aspirin 80-320 mg/day or clopidogrel 75 mg/day
  • Statin: high-intensity
  • ACE inhibitor / ARB (especially if HTN/DM)
Symptom Relief (Claudication)
  • Cilostazol 100 mg 2x1 (first-line for walking improvement)
  • Alternative: pentoxifylline (less effective)
Revascularizations
Indications
  • Lifestyle-limiting claudication despite therapy
  • Critical limb ischemia (rest pain, ulcer, gangrene)
Options
  • Endovascular (First-Line in many cases)
    • Angioplasty ± stent
  • Surgical
    • Bypass graft (for extensive disease)
Management by Severity
Claudication (Fontaine II / Rutherford 1–3)
  • Lifestyle + drugs
  • Exercise therapy
  • Consider revascularization if refractory
Critical Limb Ischemia (Fontaine III–IV / Rutherford 4–6)
  • Urgent revascularization
  • Wound care
  • Analgesia
  • Amputation if non-salvageable
Acute Limb Ischemia (Emergency)
  • Immediate heparin anticoagulation
  • Urgent revascularization (embolectomy/thrombolysis)