What is the initial workup and management for peripheral artery disease (PAD) in primary care?

Initial Workup and Management of Peripheral Artery Disease in Primary Care

Primary care providers should perform a structured assessment for peripheral artery disease (PAD) in high-risk patients, including ankle-brachial index (ABI) measurement, comprehensive risk factor modification, and appropriate medical therapy, with referral for revascularization only for those with significant disability or critical limb ischemia. 1

Identifying High-Risk Patients

Screening for PAD should focus on the following high-risk groups:

• Age ≥65 years
• Age 50-64 years with risk factors (diabetes, smoking, hyperlipidemia, hypertension)
• Age <50 years with diabetes and at least one additional atherosclerotic risk factor
• Known atherosclerotic disease in another vascular bed (coronary, carotid, etc.)
• Family history of PAD 1, 2

Initial Clinical Assessment

History

• Assess for exertional leg symptoms, including:
  • Classic claudication (reproducible calf pain with walking that resolves with rest)
  • Atypical leg symptoms (thigh or buttock discomfort)
  • Walking impairment
  • Ischemic rest pain
  • Nonhealing wounds 1

Physical Examination

• Comprehensive pulse examination (femoral, popliteal, dorsalis pedis, posterior tibial)
• Auscultation for femoral bruits
• Inspection of legs and feet for:
  • Color changes
  • Temperature differences
  • Trophic skin changes (hair loss, skin thinning)
  • Ulcerations or wounds
  • Edema 1, 2

Blood Pressure Measurement

• Measure blood pressure in both arms at least once during initial assessment
• Difference >15 mmHg may indicate subclavian stenosis 1

Diagnostic Testing

Ankle-Brachial Index (ABI)

• First-line diagnostic test for suspected PAD
• Calculate by dividing the higher ankle pressure (dorsalis pedis or posterior tibial) by the higher arm pressure
• Interpretation:
  • 1.00-1.40: Normal
  • 0.91-0.99: Borderline
  • ≤0.90: Abnormal (diagnostic of PAD)

  • 1.40: Noncompressible vessels (requires alternative testing) 1, 2, 3

Additional Testing When Indicated

• Exercise ABI testing: For patients with normal resting ABI but typical symptoms
• Toe-Brachial Index (TBI): For patients with noncompressible arteries (ABI >1.40)
  • TBI >0.70 is normal; ≤0.70 is abnormal
• Segmental pressure measurements and pulse volume recordings: To localize disease 1

Imaging Studies

• Not indicated for patients with normal post-exercise ABI unless other atherosclerotic causes are suspected
• Duplex ultrasound: First-line imaging to determine anatomic location and degree of stenosis
• CT angiography or MR angiography: Consider when revascularization is being considered 1, 2

Management Approach

Medical Therapy (for all PAD patients)

1. Antiplatelet therapy:

   • Aspirin 75-325 mg daily OR
   • Clopidogrel 75 mg daily (especially if aspirin intolerant)

2. Lipid management:

   • High-intensity statin therapy regardless of baseline LDL levels

3. Blood pressure control:

   • Target <130/80 mmHg
   • ACE inhibitors or ARBs preferred (especially with diabetes or chronic kidney disease)

4. Diabetes management:

   • Target HbA1c <7%

5. Smoking cessation:

   • Behavioral counseling
   • Pharmacotherapy (nicotine replacement, bupropion, varenicline) 1, 2, 4

Exercise Therapy

• Supervised exercise program (30-45 min/session, 3 times/week for 12 weeks)
• Structured home-based exercise program if supervised program unavailable 2, 4

Pharmacotherapy for Claudication

• Cilostazol 100 mg twice daily (contraindicated in heart failure)
• Consider for patients with lifestyle-limiting claudication despite exercise therapy 3, 4

Indications for Referral to Vascular Specialist

1. Critical limb ischemia (CLI):

   • Rest pain
   • Nonhealing wounds
   • Gangrene
   • ABI <0.4 in patients with diabetes

2. Lifestyle-limiting claudication despite optimal medical therapy and exercise program

3. Acute limb ischemia (emergent referral):

   • Sudden onset of pain, pallor, pulselessness, paresthesia, paralysis, poikilothermia

4. Abnormal ABI with atypical symptoms requiring further evaluation

5. Noncompressible vessels (ABI >1.40) with symptoms suggestive of PAD 1

Follow-up Care

• Periodic clinical evaluation including assessment of cardiovascular risk factors, limb symptoms, and functional status
• Repeat ABI measurement after revascularization (change of 0.15 is clinically significant)
• Regular foot inspection, especially in patients with diabetes
• Patients with history of CLI should be evaluated at least twice annually by a vascular specialist 1

Common Pitfalls to Avoid

1. Underdiagnosis: PAD is frequently underdiagnosed in primary care, with physician awareness of the diagnosis as low as 49% 5

2. Relying solely on classic claudication symptoms: Only 10-11% of PAD patients present with classic claudication 5, 3

3. Missing PAD in patients with normal ABI: Consider exercise ABI or alternative testing in symptomatic patients with normal resting ABI 6

4. Inadequate risk factor modification: Patients with PAD often receive less intensive treatment for lipid disorders, hypertension, and antiplatelet therapy compared to patients with coronary artery disease 5

5. Overlooking patients with noncompressible arteries: These patients require TBI or other alternative testing 2, 6