In an 82-year-old female with peripheral arterial disease who had ankle‑brachial index testing showing a right toe‑brachial index of 0.9 and a left toe‑brachial index of 0.5, what is the appropriate management?

Management of Asymmetric Toe-Brachial Index Results in an 82-Year-Old Female with PAD

This patient requires immediate comprehensive medical management and urgent vascular evaluation for the left lower extremity given the critically low TBI of 0.5, which indicates severe PAD and risk for chronic limb-threatening ischemia, while the right leg with TBI 0.9 represents borderline normal perfusion.

Interpretation of TBI Values

The toe-brachial index is particularly valuable in elderly patients where ankle-brachial index may be falsely elevated due to medial arterial calcification 1. Based on current evidence:

• Right TBI 0.9: This is at the borderline of normal (normal reference value ≥0.71) 2
• Left TBI 0.5: This is severely abnormal and indicates significant arterial disease with high risk for limb-threatening ischemia 2, 3

A TBI <0.7 has 90-100% sensitivity for detecting vessel stenosis 2, and the left leg clearly falls well below this threshold.

Immediate Management Algorithm

1. Comprehensive Medical Therapy (Initiate Immediately)

Per 2024 ACC/AHA guidelines 4, all patients with symptomatic PAD should receive:

• Antiplatelet therapy: Low-dose rivaroxaban 2.5 mg twice daily PLUS low-dose aspirin (Class 1 recommendation) to reduce major adverse cardiovascular events (MACE) and major adverse limb events (MALE) 4
• High-intensity statin therapy: Maximize dose regardless of baseline LDL-C
• If LDL-C remains ≥70 mg/dL on maximally tolerated statin: Add ezetimibe or PCSK9 inhibitor (Class 2a recommendation) 4
• Blood pressure control: Target appropriate for age and comorbidities
• Smoking cessation: If applicable

2. Urgent Vascular Evaluation for Left Lower Extremity

The left TBI of 0.5 warrants:

• Arterial duplex ultrasound to characterize lesion location and severity 1
• Assessment for chronic limb-threatening ischemia (CLTI): Evaluate for rest pain, tissue loss, or non-healing wounds
• Vascular surgery/interventional consultation for potential revascularization planning

3. Determine Symptom Status and Functional Impact

If asymptomatic or mild claudication:

• Structured supervised exercise therapy is a core component of care 5, 4
• Continue aggressive medical management
• Close monitoring for progression

If symptomatic claudication not responsive to medical therapy and exercise:

• Revascularization (endovascular, surgical, or hybrid) can improve quality of life and functional status 4

If CLTI (rest pain, tissue loss, gangrene):

• Revascularization should be used to prevent limb loss 4
• Multispecialty care team involvement is essential 4

4. Foot Care and Prevention

Given the severe left-sided disease:

• Meticulous foot care is crucial across all PAD clinical subsets 4
• Podiatry referral for preventive care and patient education
• Daily foot inspection for wounds or pressure points
• Proper footwear to prevent trauma

Critical Pitfalls to Avoid

• Do not delay vascular evaluation for the left leg—TBI 0.5 represents severe disease requiring urgent assessment
• Do not rely on symptoms alone—elderly patients may have limited mobility masking claudication symptoms
• Do not use single antiplatelet therapy alone in symptomatic PAD when dual pathway inhibition (rivaroxaban + aspirin) has proven superior outcomes 4
• Do not forget cardiovascular risk reduction—PAD patients have high risk for myocardial infarction and stroke

Right Leg Management

The right TBI of 0.9, while borderline, requires:

• Same aggressive medical management as above
• Monitoring for progression
• Exercise therapy to improve functional capacity
• May not require immediate revascularization unless symptomatic

Monitoring Plan

• Serial TBI measurements to track disease progression
• Functional assessment with walking distance/quality of life metrics
• Cardiovascular risk factor optimization with regular follow-up
• Immediate evaluation for any new symptoms suggesting acute limb ischemia

The asymmetry between limbs (0.9 vs 0.5) is clinically significant and the left leg requires urgent attention to prevent limb loss, while both legs benefit from comprehensive medical management to reduce cardiovascular morbidity and mortality.