What are the diagnostic tests and treatment options for peripheral artery disease?

Diagnostic Tests and Treatment Options for Peripheral Artery Disease

The ankle-brachial index (ABI) is the recommended first-line diagnostic test for peripheral artery disease (PAD), with additional physiological testing and imaging studies indicated based on clinical presentation and initial findings. 1

Diagnostic Testing Algorithm

Initial Assessment

• History and physical examination findings suggestive of PAD:
  • Exertional leg symptoms (claudication, leg fatigue, weakness)
  • Ischemic rest pain
  • Nonhealing wounds
  • Abnormal pulse examination (absent or diminished pulses)
  • Vascular bruits
  • Skin changes (pallor, dependent rubor, hair loss, atrophic skin)

First-Line Diagnostic Test

• Resting ABI measurement 1
  • Interpretation:
    • Abnormal: ≤0.90 (confirms PAD)
    • Borderline: 0.91-0.99 (requires additional testing)
    • Normal: 1.00-1.40
    • Noncompressible: >1.40 (requires alternative testing)

Additional Testing Based on Initial ABI Results

• For normal or borderline ABI (>0.90) with suspected PAD:

  • Exercise treadmill ABI testing 1
  • A post-exercise ABI decrease >20% is diagnostic for PAD 1

• For noncompressible arteries (ABI >1.40):

  • Toe pressure/toe-brachial index (TBI) with waveforms 1
  • TBI <0.70 indicates PAD 2
  • Transcutaneous oxygen pressure (TcPO2) measurement 1

• For confirmed PAD requiring anatomical assessment:

  • Duplex ultrasound (first-line imaging) 1
  • Segmental leg pressures with pulse volume recordings (PVR) 1
  • CT angiography (CTA) for aorto-iliac or multisegmental disease 1
  • MR angiography (MRA) for detailed anatomical assessment 1

Treatment Options

Medical Therapy (First-Line for All PAD Patients)

1. Risk Factor Modification:

   • Smoking cessation (highest priority)
   • Diabetes management (target HbA1c <7%)
   • Blood pressure control (<140/90 mmHg)
   • Lipid management (high-intensity statin therapy)

2. Antiplatelet Therapy:

   • Aspirin (75-325 mg daily) or
   • Clopidogrel (75 mg daily) 3, 4

3. Statin Therapy:

   • High-intensity statin regardless of baseline LDL level 3

4. Exercise Therapy:

   • Supervised exercise program (30-45 minutes, 3 times weekly) 4
   • Home-based exercise for patients without access to supervised programs

5. Pharmacologic Therapy for Claudication:

   • Cilostazol (100 mg twice daily) - contraindicated in heart failure 4
   • Pentoxifylline (400 mg three times daily) - less effective alternative 5

Revascularization (For Selected Patients)

• Indications:

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

• Options:

  1. Endovascular Therapy:

     • Angioplasty with or without stenting
     • Atherectomy
     • Best for focal, proximal disease

  2. Surgical Revascularization:

     • Bypass surgery
     • Endarterectomy
     • Preferred for extensive, multisegmental disease

  3. Hybrid Procedures:

     • Combination of endovascular and surgical approaches

Special Considerations

Critical Limb-Threatening Ischemia (CLTI)

• Defined by:
  • Ischemic rest pain
  • Tissue loss (ulcers, gangrene)
  • Ankle pressure <50 mmHg or toe pressure <30 mmHg 1
• Requires urgent vascular evaluation and revascularization to prevent amputation

Masked PAD

• Patients with PAD but without typical symptoms due to:
  • Limited walking ability from other conditions
  • Reduced pain sensitivity (e.g., diabetic neuropathy) 1
• These patients are at high risk for both cardiovascular events and limb events

Diabetic Patients

• Higher risk of PAD with more severe presentations
• TBI preferred over ABI due to medial arterial calcification 1
• Comprehensive foot examination and wound assessment using WIfI classification (Wound, Ischemia, and foot Infection) 1

Common Pitfalls to Avoid

• Failing to screen high-risk patients (age ≥65, diabetes, smoking history)
• Attributing leg symptoms solely to arthritis or neuropathy without vascular assessment
• Overlooking PAD in patients with normal pulses (collateral circulation may maintain pulses)
• Delaying treatment for acute limb ischemia (can lead to irreversible tissue damage)
• Failing to address inflow disease before outflow disease in multilevel disease 2
• Relying solely on ABI in patients with diabetes or renal failure (use TBI) 1

By following this systematic approach to diagnosis and treatment, clinicians can effectively identify PAD, reduce cardiovascular morbidity and mortality, improve functional status, and prevent limb loss in affected patients.