What are the recommended initial tests to screen for Peripheral Vascular Disease (PVD) in at-risk patients?

Screening Tests for Peripheral Vascular Disease

Primary Screening Test

The resting ankle-brachial index (ABI) is the recommended initial screening test for peripheral vascular disease in at-risk patients. 1, 2

Who Should Be Screened

Screen patients meeting any of these criteria:

• Age ≥65 years (all patients in this age group) 1, 2
• Age 50-64 years with atherosclerotic risk factors including diabetes mellitus, smoking history, hyperlipidemia, hypertension, or family history of PAD 1, 2
• Age <50 years with diabetes plus one additional atherosclerotic risk factor 1, 2
• Known atherosclerotic disease in another vascular bed (coronary, carotid, subclavian, renal, mesenteric artery stenosis, or abdominal aortic aneurysm) 1, 2

Initial Clinical Assessment Before Testing

Perform these specific evaluations:

• Pulse palpation of femoral, popliteal, dorsalis pedis, and posterior tibial arteries (rated 0=absent, 1=diminished, 2=normal, 3=bounding) 1
• Auscultation for femoral bruits 1
• Inspection of legs and feet for nonhealing wounds, gangrene, elevation pallor, or dependent rubor 1
• Blood pressure measurement in both arms to identify the highest systolic pressure (required for accurate ABI calculation) and detect subclavian stenosis 1

ABI Interpretation and Next Steps

Normal or Borderline ABI (>0.90 to ≤1.40)

• If symptomatic with exertional leg symptoms: Proceed to exercise treadmill ABI testing 1, 2
• A post-exercise ABI decrease >20% confirms PAD diagnosis 1, 2
• Exercise testing enhances sensitivity for detecting PAD when resting ABI is normal 3

Abnormal ABI (≤0.90)

• Confirms PAD diagnosis 1, 2
• Report separately for each leg 1

Noncompressible Arteries (ABI >1.40)

• Measure toe-brachial index (TBI) as the next test 1, 2
• TBI <0.70 indicates PAD 2, 4
• TBI is essential in patients with diabetes or chronic kidney disease who commonly have arterial calcification 1, 2

Critical Pitfalls to Avoid

• Do not rely solely on resting ABI in symptomatic patients: Nearly half of patients with suspected PAD have normal resting ABI, requiring exercise testing for diagnosis 3
• Do not skip bilateral arm blood pressure measurement: This causes inaccurate ABI calculations and misses subclavian stenosis 1, 2
• Do not use ABI alone in diabetic or dialysis patients: Vascular calcification causes falsely elevated ABI values; use TBI instead 1, 2
• Do not expect classic claudication symptoms: Only approximately 10% of PAD patients present with typical claudication; many have atypical symptoms or are asymptomatic 2
• Do not perform invasive angiography for asymptomatic PAD: This is not recommended for screening or diagnosis 1, 2

When to Proceed to Anatomic Imaging

Reserve duplex ultrasound, CTA, or MRA for:

• Symptomatic patients being considered for revascularization 1
• Anatomic localization and severity assessment when intervention is planned 1
• Never for asymptomatic PAD screening 1, 2

Special Populations

Dialysis Patients

• Physical examination at dialysis initiation including pulse assessment and skin integrity evaluation 1
• Proceed to specialized studies (duplex or invasive testing) only if abnormalities detected and intervention considered 1
• ABI may be falsely elevated; TBI is more reliable 1

Patients with Chronic Wounds

• Apply WIfI (Wound, Ischemia, and foot Infection) classification to assess amputation risk 1
• Measure critical limb perfusion parameters: ankle pressure <50 mmHg, toe pressure <30 mmHg, or transcutaneous oxygen pressure (TcPO2) <30 mmHg 1