What is the approach to diagnosing Peripheral Vascular Disease (PVD)?

Diagnostic Approach to Peripheral Vascular Disease (PVD)

The diagnosis of PVD begins with measuring the ankle-brachial index (ABI) as the first-line test, using an ABI ≤0.90 as the diagnostic criterion, followed by targeted additional testing based on initial results and clinical presentation. 1

Initial Clinical Assessment

Patient Identification for Testing

Screen the following populations systematically 2:

• All patients aged ≥65 years
• Patients aged 50-64 years with atherosclerosis risk factors (diabetes, smoking, hypertension, hyperlipidemia)
• Any patient with known atherosclerotic disease in other vascular beds (coronary, carotid, renal arteries, or abdominal aortic aneurysm)

Focused History

Document these specific elements 1, 3:

• Claudication symptoms: Pain in leg muscles with exercise that resolves with rest
• Ischemic rest pain: Pain at rest, particularly at night
• Walking impairment: Quantify distance before symptoms occur
• Nonhealing wounds: Location, duration, and associated symptoms
• Risk factors: Smoking history, diabetes duration and control, hypertension, hyperlipidemia
• Family history: Retinal detachment or vascular disease in first-degree relatives

Physical Examination Findings

Perform these specific assessments with shoes and socks removed 3, 4:

• Pulse palpation: Rate dorsalis pedis and posterior tibial pulses (0=absent, 1=diminished, 2=normal, 3=bounding)
• Bilateral arm blood pressure: Difference >15 mmHg suggests subclavian stenosis 1
• Femoral artery auscultation: Bruits increase likelihood of PVD 3
• Skin inspection: Elevation pallor, dependent rubor, asymmetric hair loss, trophic changes, cool temperature, blue/purple discoloration 3, 4
• Venous filling time: >20 seconds is highly specific for severe disease 5

Diagnostic Testing Algorithm

Step 1: Resting Ankle-Brachial Index (ABI)

This is the mandatory first test 1:

• Sensitivity: 68-84%, Specificity: 84-99% for PAD diagnosis 1
• Measure highest systolic pressure at ankle (posterior tibial or dorsalis pedis) divided by highest brachial pressure

Interpretation 1, 3:

• ≤0.90: Confirms PAD diagnosis
• 0.91-0.99: Borderline—proceed to exercise ABI
• 1.00-1.40: Normal range
• >1.40: Non-compressible arteries (medial calcification)—proceed to alternative testing

Step 2: Additional Testing Based on ABI Results

For ABI >1.40 (Non-compressible arteries) 1, 2:

• Toe-brachial index (TBI): Use photoplethysmography probe on distal pulp of first or second toe
• TBI <0.70 confirms PAD
• This is particularly important in diabetic patients and those with chronic kidney disease who commonly have arterial calcification

For Borderline ABI (0.91-0.99) with Symptoms 1, 2:

• Exercise treadmill ABI: Post-exercise ABI decrease >20% confirms PAD
• Perform when clinical suspicion remains high despite normal resting ABI

For Normal ABI with High Clinical Suspicion 2:

• Consider exercise ABI testing
• Duplex ultrasonography may provide anatomic information 6

Step 3: Severity Assessment in Confirmed PAD

For patients with chronic wounds or tissue loss 1, 2:

• Ankle pressure: <50 mmHg indicates critical limb-threatening ischemia (CLTI)
• Toe pressure: <30 mmHg indicates CLTI
• Transcutaneous oxygen pressure (TcPO₂): <30 mmHg at first intermetatarsal position indicates CLTI
• Apply WIfI (Wound, Ischemia, foot Infection) classification to estimate amputation risk

For patients with dense vitreous hemorrhage obscuring examination (note: this appears to be from ophthalmology guidelines and is not relevant to peripheral vascular disease diagnosis)

Special Populations and Pitfalls

Critical Pitfalls to Avoid 2, 3:

• Bilateral arm pressure measurement is mandatory: Failing to measure both arms leads to inaccurate ABI calculations
• Don't rely on classic claudication alone: Only 10% of PAD patients present with typical symptoms; many are asymptomatic or have "masked PAD" (unable to walk enough to reveal symptoms due to comorbidities or neuropathy)
• Don't skip TBI in diabetics: Diabetes and renal disease cause medial calcification, making ABI unreliable
• Don't perform invasive angiography in asymptomatic patients: Reserve angiographic imaging for revascularization planning only

Masked PAD Recognition 1:

Identify patients with severe disease but no symptoms due to:

• Inability to walk sufficient distance (heart failure, arthritis)
• Reduced pain sensitivity (diabetic neuropathy)
• These patients can rapidly progress from "asymptomatic" to severe CLTI with minor trauma

When to Refer to Vascular Specialist 3:

• ABI <0.40 (severe obstruction)
• Symptoms of claudication or ischemic rest pain
• Any nonhealing wound with absent pulses
• Toe necrosis or gangrene
• Consideration for revascularization

The 2024 ESC guidelines 1 represent the most current evidence and emphasize that comprehensive laboratory evaluation (lipid profile including lipoprotein[a], fasting glucose, HbA1c, renal function, inflammatory markers) should accompany the diagnostic workup, as PVD is a marker of systemic atherosclerosis with significantly elevated cardiovascular mortality risk.