Medical Wikipedia : The Medical Encyclopedia
Ankle-Brachial Index
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 Index | ABI |
|---|---|
| Ankle Brachial Index | ABI |
| ABI : 1.00– 1.40 | Normal ABI |
| ABI : 0.91–0.99 | Borderline ABI |
| ABI < 0.90 | Diagnostic of PAD |
| ABIs >1.40 | Noncompressible arteries secondary to vascular calcification |
| Unable to occlude blood vessel at 300mmHg of pressure application. | Non-measurable |
What are the arteries used for Ankle-Brachial Index?
Ankle-brachial index is measured using three arteries:
- Brachial artery for the upper extremity
- Dorsalis pedis artery
- Posterior tibial artery at the ankle.
'Dorsalis pedis' 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?
- Deep vein thrombosis (DVT): -concern for breaking and embolizing a thrombus.
- 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 :
- First Arm
- Same side Ankle (both Posterior Tibial and Dorsalis Pedis)
- Opposite Leg
- Opposite Arm.
How is ABI correlates the prediction of events?
Studies shows - ABI correlation facts |
| 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. |
Studies shows ABI correlates with:
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