Diagnostic Approach to Peripheral Arterial Disease

Initial Assessment

The American College of Cardiology and the European Heart Journal recommend using the ankle-brachial index (ABI) with Doppler ultrasound as the first-line diagnostic test for patients with suspected peripheral arterial disease, with results interpreted as follows: ≤0.90: Abnormal (PAD confirmed), 0.91-0.99: Borderline, 1.00-1.40: Normal, and >1.40: Noncompressible vessels 1, 2, 3

The diagnostic approach involves:

Step	Test
Initial test	Resting ABI with or without pulse volume recordings (PVR)/Doppler waveforms
If ABI ≤0.90	PAD diagnosis confirmed
If ABI is borderline (0.91-0.99) or normal (1.00-1.40) but clinical suspicion remains	Perform exercise treadmill ABI testing
If ABI >1.40 (noncompressible vessels)	Perform toe pressure/toe-brachial index (TBI) with waveforms

1, 4, 3

For patients with normal or borderline ABI results but persistent symptoms, exercise treadmill ABI testing is recommended, with a post-exercise ABI decrease >20% being diagnostic for PAD 1, 5, 4, 3
In patients with noncompressible vessels (ABI >1.40), the European Heart Journal suggests performing toe-brachial index (TBI) with waveforms, particularly in diabetic patients and those with renal failure 1, 2
Consider TBI when there is clinical peripheral neuropathy or high risk of arterial calcification, particularly in diabetic patients, as recommended by the American College of Cardiology and the European Heart Journal 5, 4, 6, 1, 3

The European Heart Journal recommends duplex ultrasound (DUS) as the first-line imaging method to confirm PAD lesions, providing anatomical characterization and localization of disease 2, 3
For revascularization planning, CT Angiography (CTA) or MR Angiography (MRA) are recommended for symptomatic patients with aorto-iliac disease, multisegmental/complex disease, or revascularization planning 2, 3

ABI classification and interpretation is as follows:

ABI Value	Classification	Interpretation	Next Steps
≤0.90	Abnormal	PAD confirmed	Initiate treatment, risk assessment
0.91-0.99	Borderline	Possible PAD	Exercise ABI testing
1.00-1.40	Normal	No significant PAD	If symptomatic, exercise ABI or other tests
>1.40	Noncompressible	Medial arterial calcification	Toe-brachial index (TBI)

5, 4, 6

Diabetic patients are at higher risk of both PAD and neuropathy, and ABI may be falsely elevated due to arterial calcification, making TBI a more reliable diagnostic tool 2
The WIfI classification system is recommended to estimate amputation risk in patients with chronic wounds 2
ABI provides prognostic information, identifying patients with approximately twice the risk of myocardial infarction and cardiovascular death 6, 5, 4, 1, 7, 8

Optimal medical treatment should be initiated, including antiplatelet therapy, high-intensity statins, blood pressure control, diabetes management (if present), and smoking cessation (if applicable), as recommended by the American College of Cardiology 9
The American College of Cardiology recommends maintaining therapeutic support, including optimal medical treatment (antiplatelet agents, high-intensity statins), controlling cardiovascular risk factors, and regular foot care and surveillance 1
Annual ABI monitoring is recommended to assess disease progression, as part of a comprehensive management plan, and regular foot examinations and meticulous foot care are essential for patients with PAD, as suggested by the American College of Cardiology and the European Heart Journal 8, 5, 1, 6