What are the diagnostic criteria for Peripheral Vascular Disease (PVD)?

Diagnostic Criteria for Peripheral Vascular Disease (PVD)

The ankle-brachial index (ABI) is the recommended initial non-invasive diagnostic test to confirm peripheral vascular disease, with an ABI ≤0.90 definitively establishing the diagnosis of PAD. 1

Primary Diagnostic Tests

Ankle-Brachial Index (ABI)

• Normal ABI: 1.00-1.40
• Borderline ABI: 0.91-0.99 (requires additional testing)
• Abnormal ABI: ≤0.90 (confirms PAD diagnosis)
• Non-compressible arteries: >1.40 (requires alternative testing) 1

Measurement Technique

• Patient in supine position
• 5-10 minutes of rest before measurement
• Constant room temperature
• Cuffs placed on upper arms and lower limbs (just above the ankle)
• Calculate ratio of highest systolic ankle pressure to highest systolic brachial pressure 1

Secondary Diagnostic Tests

For Borderline ABI or Non-compressible Arteries

1. Toe-Brachial Index (TBI)

   • Recommended when ABI >1.40 (non-compressible arteries)
   • Abnormal TBI: ≤0.70
   • Measurement: Cuffs on upper arms and photoplethysmography probe on distal pulp of first or second toe 1

2. Exercise Treadmill ABI Testing

   • Essential for patients with normal/borderline resting ABI (>0.90) but exertional symptoms
   • Post-exercise ABI decrease >20% is diagnostic for PAD
   • Measured 1 minute after standardized treadmill exercise 1

For Critical Limb Perfusion Assessment

• Ankle pressure: <50 mmHg indicates critical limb ischemia
• Toe pressure: <30 mmHg indicates critical limb ischemia
• Transcutaneous oxygen pressure (TcPO2): <30 mmHg indicates critical limb ischemia 1

Anatomic Imaging (When Revascularization is Considered)

Imaging is indicated only for patients with:

1. Functionally limiting claudication with inadequate response to medical therapy
2. Critical limb-threatening ischemia
3. Suspected PAD with inconclusive ABI/physiological testing 1

Options include:

• Duplex ultrasound: Non-invasive, no radiation/contrast, but operator-dependent
• CT angiography (CTA): Detailed anatomy but requires contrast and radiation
• MR angiography (MRA): Detailed anatomy without radiation but requires contrast
• Catheter angiography: Gold standard but invasive, used primarily when revascularization is planned 1

Clinical Classification of PAD

1. Asymptomatic PAD: Abnormal ABI without symptoms
2. Symptomatic PAD: Intermittent claudication or atypical leg symptoms with abnormal ABI
3. Masked PAD: PAD without provoked leg pain due to reduced walking capacity or pain sensitivity
4. Chronic Limb-Threatening Ischemia (CLTI): Ischemic rest pain, gangrene, or non-healing chronic wound with critical limb perfusion 1

Risk Assessment Tools

For patients with chronic wounds, the WIfI classification system (Wound, Ischemia, and foot Infection) should be used to estimate amputation risk 1

Differential Diagnosis Considerations

Several conditions can mimic PAD symptoms:

• Hip/ankle arthritis
• Nerve root compression
• Spinal stenosis
• Popliteal cyst
• Venous claudication
• Chronic compartment syndrome 2

Important Clinical Considerations

• PAD is a marker for systemic atherosclerosis with 4-5× increased risk of cardiovascular events 1
• Patients with critical limb ischemia have 25-35% 1-year mortality 2
• Delaying treatment for acute limb ischemia can lead to irreversible tissue damage within 4-6 hours 2
• Annual ABI measurement should be performed in patients diagnosed with PAD 2

The diagnostic approach to PAD requires a systematic assessment beginning with ABI measurement and progressing to more specialized tests based on clinical presentation and initial findings. Imaging studies should be reserved for patients in whom revascularization is being considered rather than for routine diagnosis.