What is the management plan for a patient with abnormal Ankle-Brachial Index (ABI) and Toe-Brachial Index (TBI) results, indicating severe Peripheral Artery Disease (PAD)?

Management of Severe Peripheral Artery Disease with Non-Compressible Vessels

This patient requires urgent vascular surgery or interventional radiology consultation for revascularization planning, as the right leg TBI of 0.61 indicates severe PAD with critical limb ischemia risk, while the non-compressible vessels bilaterally necessitate anatomic imaging with duplex ultrasound, CTA, or MRA to determine lesion location and severity. 1, 2

Interpretation of Results

Right Leg Assessment

• The right posterior tibial artery is non-compressible (ABI >1.40), making standard ABI unreliable for diagnosis 1
• The TBI of 0.61 is abnormal and diagnostic of severe PAD (TBI ≤0.70 confirms PAD in non-compressible vessels) 1, 2
• This represents severe arterial insufficiency requiring urgent evaluation 2

Left Leg Assessment

• Both posterior tibial and dorsalis pedis arteries are non-compressible bilaterally 1
• The left TBI of 1.07 appears normal, but non-compressible vessels indicate medial arterial calcification (common in diabetes and end-stage renal disease), which can falsely elevate pressure measurements 1, 3
• The discrepancy between non-compressible vessels and "normal" TBI warrants additional perfusion assessment 1, 2

Immediate Management Steps

1. Urgent Anatomic Imaging (Class I Recommendation)

Order duplex ultrasound, CTA, or MRA of bilateral lower extremities to identify stenosis location and severity for revascularization planning 1, 2

• All three modalities are Class I recommendations with equal standing 1
• Choice depends on institutional availability and patient factors (renal function for CTA contrast, contraindications to MRA) 1
• Invasive angiography is reasonable if revascularization is being considered, particularly given the severity 1

2. Additional Perfusion Assessment (Class IIa Recommendation)

Obtain transcutaneous oxygen pressure (TcPO2) and/or skin perfusion pressure (SPP) measurements bilaterally to assess tissue viability and predict wound healing potential 1, 2

• TcPO2 >30 mmHg predicts ulcer healing 2
• SPP ≥30-50 mmHg is associated with wound healing 2
• These measurements are particularly important given non-compressible vessels that may mask true perfusion status 1, 2

3. Clinical Assessment for Critical Limb Ischemia

Examine both legs directly with shoes and socks removed to assess for: 1

• Ischemic rest pain (pain at rest, particularly at night, relieved by dependency)
• Non-healing wounds or ulcerations
• Gangrene or tissue loss
• Skin temperature, color changes, hair loss
• Evidence of infection requiring systemic antibiotics 1

If any signs of CLI are present, this becomes a vascular emergency requiring same-day vascular consultation 1, 2

Concurrent Medical Management (Initiate Immediately)

Antiplatelet Therapy (Class I Recommendation)

Start clopidogrel 75 mg daily (preferred over aspirin for PAD) 4, 3

• Alternative: aspirin 75-325 mg daily if clopidogrel contraindicated 4

Lipid Management (Class I Recommendation)

Initiate high-intensity statin therapy targeting LDL <70 mg/dL 4, 3

Blood Pressure Control

Target BP <140/90 mmHg (or <130/80 mmHg if diabetes or chronic kidney disease present) 4

ACE Inhibitor Therapy (Class I Recommendation)

Start ACE inhibitor for cardiovascular risk reduction 4

Risk Factor Modification

• Smoking cessation if applicable (highest priority intervention) 4, 3
• Diabetes management to HbA1c <7% if diabetic 4
• Structured exercise therapy once revascularization status determined 3, 5

Screening for Associated Conditions

Abdominal Aortic Aneurysm Screening (Class IIa Recommendation)

Order screening duplex ultrasound for AAA, as PAD is a significant risk factor for aneurysmal disease 1, 4

Cardiovascular Risk Assessment

Assess for coronary and carotid artery disease, as patients with PAD in one vascular bed have higher prevalence of atherosclerosis in other arterial beds 1, 4

Follow-Up Plan

If Revascularization Performed

Schedule follow-up with vascular specialist at least twice annually due to high recurrence risk after CLI treatment 1

• Regular foot inspection at each visit 1
• Periodic vascular examination including pulse assessment 4

If Conservative Management

Monitor for progression to CLI with regular foot inspections, as patients with TBI <0.70 are at elevated risk 1, 4

Critical Pitfalls to Avoid

• Do not rely on ABI alone when vessels are non-compressible – this is why TBI was appropriately obtained 1
• Do not delay vascular consultation for a right leg TBI of 0.61, as this represents severe disease 2
• Do not assume the left leg is normal despite TBI 1.07 – non-compressible vessels require additional perfusion assessment 1, 2
• Do not perform anatomic imaging on asymptomatic patients without physiologic evidence of PAD (Class III Harm recommendation), but this patient has abnormal TBI 1
• Do not overlook wound care referral if any skin breakdown is present 1