Ankle-Brachial Index (ABI)
Ankle-Brachial Index (ABI): Overview, Procedure, and Clinical Significance
What is the Ankle-Brachial Index?
The Ankle-Brachial Index (ABI) is a simple, non-invasive diagnostic test used to assess peripheral arterial disease (PAD) by comparing the blood pressure measured at the ankle with the blood pressure measured at the arm (brachial artery). It helps determine the presence and severity of arterial blockages that can restrict blood flow to the legs and feet.
Procedure
The ABI test is performed using a blood pressure cuff and a Doppler ultrasound device:
- Blood pressure is measured in both arms to obtain the brachial systolic pressure.
- Blood pressure is then measured at both ankles, usually at the posterior tibial and dorsalis pedis arteries.
- The ABI is calculated for each leg by dividing the higher ankle systolic pressure by the higher brachial systolic pressure.
- An ABI of 1.0 to 1.4 is considered normal, whereas an ABI below 0.9 typically indicates peripheral arterial disease.
Clinical Significance
ABI is an important tool for diagnosing PAD, which is a common circulatory problem characterized by narrowed arteries reducing blood flow to the limbs. It assists in early detection of PAD and monitoring its progression or response to treatment. Low ABI values correlate with increased risk of cardiovascular events such as heart attack or stroke.
This measurement also proves useful in assessing the risk of leg ulcers, poor wound healing, and amputation in diabetic and elderly patients. High ABI values (>1.4) may indicate stiff arteries due to calcification, requiring further vascular evaluation.
Key Points
- ABI is a non-invasive test comparing ankle and arm blood pressures to detect peripheral arterial disease.
- Normal ABI ranges from 1.0 to 1.4; below 0.9 suggests PAD.
- It aids early diagnosis, risk stratification, and treatment monitoring in vascular disease.
- Useful for evaluating cardiovascular risk and limb ischemia, especially in diabetic patients.
- Simple to perform, it is widely used in clinical practice for vascular screening.
Consult with Our Team of Experts Now!
For vascular health assessment or if there are symptoms suggestive of peripheral arterial disease, consult our specialists for comprehensive evaluation including ABI measurement and personalized management.
References:
Aboyans V, Criqui MH, Abraham P, et al. Measurement and interpretation of the Ankle-Brachial Index: A scientific statement from the American Heart Association. Circulation. 2012 Dec 11;126(24):2890-2909. doi:10.1161/CIR.0b013e318276fbcb. Available at: https://pubmed.ncbi.nlm.nih.gov/23008423/
