Ankle:Brachial Index

What is Ankle Brachial Index?

ABI is a non-invasive tool for the assessment of vascular status

ABI consists of the ratio between the systolic blood pressure of the lower extremity, specifically the ankle, and the upper extremity.

What is normal ABI?

Normal ABI – 1.00– 1.40 in normal individuals.

What is abnormal ABI?

Ankle Brachial IndexABI
Ankle Brachial IndexABI
ABI : 1.00– 1.40Normal ABI
ABI : 0.91–0.99Borderline ABI
ABI < 0.90Diagnostic of PAD
ABIs >1.40Noncompressible arteries secondary to vascular calcification
Unable to occlude blood vessel at 300mmHg of pressure application.Non-measurable
Ankle:Brachial Index

What are the arteries used for Ankle-Brachial Index?

Ankle-brachial index is measured using three arteries:

  1. Brachial artery for the upper extremity
  2. Dorsalis pedis artery
  3. Posterior tibial artery at the ankle.

Dorsalis pedia artery is a branch of which artery?

Dorsalis pedis artery arises primarily from the anterior tibial artery

What are the Contraindications for doing a ABI test?

  1. Deep vein thrombosis (DVT): -concern for breaking and embolizing a thrombus.
  2. Severe leg pain

What should be appropriate size of the blood pressure cuff for better measurement of blood pressure?

Blood pressure cuff (sphygmomanometer) – The appropriate size is a “width at least 40% of the limb circumference

What should be the order of Blood pressure measurement in limbs?

AHA suggests performing the order of measurements :

  1. First Arm
  2. Same side Ankle (both Posterior Tibial and Dorsalis Pedis)
  3. Opposite Leg
  4. Opposite Arm.

How is ABI correlates the prediction of events?

Studies shows ABI correlates with:

ABI correlation
ABI is better at detecting greater than 50% stenosis
Proximal lesions better detected than distal lesions.
ABI less than 0.9 with increased risk for PVD, MI, renal disease, HTN
Lower ABI also correlates with a high carotid plaque score
Higher risk of recurrent stroke
Higher vascular events/ death
Lower ABI (less than 0.7) shows an increased chance of total knee arthroplasty failure.
Patients with lower ABI more likely to have delayed healing when undergoing heart surgery.
Ankle-Brachial Index

Peripheral arterial disease results suggest that ABI is better at detecting greater than 50% stenosis and proximal lesions better than distal lesions.

ABI less than 0.9 with increased risk for PVD, MI, renal disease, HTN

Lower ABI also correlates with a high carotid plaque score

higher risk of recurrent stroke (HR 1.7)

higher vascular events/ death

Newsletter Signup

100% FREE ! Subscribe to our newsletter For Updates and New Publications in Medicine Question Bank.

Subscribe to our weekly newsletter below and never miss the latest Information. 

Medicine Questions, MCQs ,Viva questions, Image questions

100% FREE