What is the approach to diagnosing and managing Peripheral Artery Disease (PAD)?

Diagnosis and Management of Peripheral Artery Disease (PAD)

The ankle-brachial index (ABI) is the recommended first-line diagnostic test for peripheral artery disease, with a value ≤0.90 confirming the diagnosis. 1, 2

Clinical Assessment for Suspected PAD

Key History Elements

• Claudication symptoms (pain, cramping, fatigue, or weakness in leg muscles during walking that resolves with rest)
• Rest pain (especially at night, relieved by hanging leg over bed)
• Non-healing wounds or gangrene
• Risk factors: smoking, diabetes, hypertension, hyperlipidemia, advanced age
• Family history of cardiovascular disease

Physical Examination

• Pulse palpation (femoral, popliteal, dorsalis pedis, posterior tibial)
• Auscultation for femoral and abdominal bruits
• Inspection for:
  • Skin color changes (pallor on elevation, dependent rubor)
  • Temperature differences between limbs
  • Hair loss on affected limb
  • Thickened toenails
  • Ulceration or gangrene
  • Muscle atrophy

Diagnostic Algorithm

Step 1: Initial Testing

• Ankle-Brachial Index (ABI) 1
  • ≤0.90: Abnormal (confirms PAD)
  • 0.91-0.99: Borderline (requires additional testing)
  • 1.00-1.40: Normal

  • 1.40: Noncompressible arteries (requires alternative testing)

Step 2: Additional Testing Based on Initial ABI Results

For ABI ≤0.90 (Confirmed PAD):

• Segmental pressures and waveforms to localize disease
• Exercise ABI testing to assess functional limitations

For Borderline ABI (0.91-0.99) with Symptoms:

• Exercise treadmill ABI testing (post-exercise ABI decrease >20% confirms PAD)

For Noncompressible Arteries (ABI >1.40):

• Toe-Brachial Index (TBI) - abnormal if <0.70 1, 2
• Doppler waveform analysis
• Pulse volume recordings

For Suspected Critical Limb Ischemia:

• TBI <0.70
• Ankle pressure <50 mmHg
• Toe pressure <30 mmHg
• Transcutaneous oxygen pressure (TcPO2) <25 mmHg

Step 3: Anatomical Assessment (for Revascularization Planning)

Only perform if revascularization is being considered:

1. Duplex ultrasound (first-line imaging)
2. CT angiography (CTA)
3. MR angiography (MRA)
4. Invasive angiography (reserved for concurrent intervention)

Management Approach

Risk Factor Modification

• Smoking cessation
• Diabetes management (target HbA1c <7%)
• Blood pressure control (<140/90 mmHg)
• Lipid management (high-intensity statin therapy)
• Healthy diet (Mediterranean diet recommended) 1
• Regular exercise

Pharmacological Therapy

• Antiplatelet therapy: Clopidogrel 75 mg daily or aspirin 75-325 mg daily 3
• Statin therapy: High-intensity statin regardless of baseline lipid levels
• Antihypertensive therapy: ACE inhibitors or ARBs preferred

Exercise Therapy

• Supervised exercise program (30-45 minutes, 3-5 times weekly)
• Low to moderate-intensity aerobic activities 1
• Home-based exercise if supervised program unavailable

Revascularization Considerations

Consider revascularization for:

1. Lifestyle-limiting claudication despite optimal medical therapy
2. Critical limb-threatening ischemia (rest pain, tissue loss)
3. Acute limb ischemia

Special Considerations

Diabetes and PAD

• Higher prevalence of noncompressible arteries
• Use TBI instead of ABI for diagnosis
• Higher risk of ulceration and amputation
• More aggressive surveillance recommended

Common Pitfalls to Avoid

1. Failing to screen high-risk patients (diabetes, smoking history, age >65)
2. Attributing leg symptoms solely to arthritis or neuropathy
3. Relying on pulse palpation alone for diagnosis
4. Assuming "small vessel disease" is the cause of poor healing without proper vascular assessment
5. Delaying treatment for acute limb ischemia
6. Failing to address inflow disease before outflow disease in multilevel disease

Differential Diagnosis of Leg Pain

• Spinal stenosis (relieved by lumbar spine flexion)
• Hip/knee arthritis (related to weight-bearing)
• Nerve root compression (radiating pain, worse with sitting)
• Venous claudication (tight, bursting pain, history of DVT)
• Chronic compartment syndrome (after strenuous exercise)

By following this structured approach to diagnosis and management, PAD can be identified early and treated appropriately to reduce both cardiovascular and limb-related complications.