Ankle brachial index

Ankle brachial index – important in peripheral vascular disease

Both upper limb brachial blood pressures are measured and the mean is taken. Then the ankle blood pressure is taken by tying the cuff on the calf and either auscultating the posterior tibial or using the Doppler probe over the dorsalis pedis artery. The ratio between the two is known as Ankle brachial index (ABI). Normal ratio between the ankle blood pressure and brachial blood pressure is more than 1; less than 0.9 is taken as evidence of peripheral vascular disease.

ABI was initially described in 1950 for the non invasive diagnosis of lower limb peripheral arterial disease [1]. Later it was shown to be an indicator of atherosclerosis at other vascular sites and would serve as a prognostic marker for cardiovascular events as well [2].

References

1. Winsor T. Influence of arterial disease on the systolic blood pressure gradients of the extremity. Am J Med Sci. 1950; 220:117–126.
2. Victor Aboyans, Michael H Criqui, Pierre Abraham, Matthew A Allison, Mark A Creager, Curt Diehm, F Gerry R Fowkes, William R Hiatt, Björn Jönsson, Philippe Lacroix, Benôit Marin, Mary M McDermott, Lars Norgren, Reena L Pande, Pierre-Marie Preux, H E Jelle Stoffers, Diane Treat-Jacobson, American Heart Association Council on Peripheral Vascular Disease; Council on Epidemiology and Prevention; Council on Clinical Cardiology; Council on Cardiovascular Nursing; Council on Cardiovascular Radiology and Intervention, and Council on Cardiovascular Surgery and Anesthesia. Measurement and Interpretation of the Ankle-Brachial Index: A Scientific Statement From the American Heart Association. Circulation. 2012 Dec 11;126(24):2890-909.