1. What is the Ankle-Brachial Index?

The Ankle-Brachial Index (ABI) is a simple, non-invasive test that compares the blood pressure in the upper and lower limbs to assess peripheral arterial disease (PAD). It's calculated by dividing the systolic blood pressure at the ankle by the systolic blood pressure in the arm.

2. How Does the Calculator Work?

The calculator uses the ABI formula:

Where:

• Ankle Pressure — Highest systolic pressure from either ankle (mmHg)
• Brachial Pressure — Highest systolic pressure from either arm (mmHg)

Interpretation:

• 1.0-1.4: Normal
• 0.9-1.0: Borderline
• 0.8-0.9: Mild PAD
• 0.5-0.8: Moderate PAD
• <0.5: Severe PAD

3. Importance of ABI Measurement

Details: ABI is crucial for diagnosing peripheral arterial disease, assessing its severity, and predicting cardiovascular risk. It's recommended for patients with leg pain, non-healing wounds, or cardiovascular risk factors.

4. Using the Calculator

Tips: Enter the highest systolic pressure from either ankle and the highest systolic pressure from either arm. Both values must be valid (pressure > 0).

5. Frequently Asked Questions (FAQ)

Q1: Why measure ABI?
A: ABI helps diagnose peripheral arterial disease (PAD) and assess cardiovascular risk. It's simple, non-invasive, and cost-effective.

Q2: How should pressures be measured?
A: Use a Doppler ultrasound device and blood pressure cuff. Measure both arms and both ankles (dorsalis pedis and posterior tibial arteries).

Q3: What if ABI is >1.4?
A: Values >1.4 suggest non-compressible arteries (common in diabetes or advanced age). Toe-brachial index may be more accurate in these cases.

Q4: When should ABI be repeated?
A: For known PAD, repeat annually or with symptom changes. For high-risk patients without PAD, consider every 2-5 years.

Q5: Are there limitations to ABI?
A: ABI may be less accurate in patients with medial arterial calcification, acute limb ischemia, or venous congestion.