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ankle-brachial index (ABI) or ankle-arm index (AAI)

Indications: - evaluation of suspected peripheral arterial disease Contraindications: - screening for peripheral arterial disease [8] Procedure: Systolic blood pressure, measured by doppler. posterior tibial artery (ankle) / brachial artery (antecubital fossa) * the higher brachial artery pressure is used (regardless of side) Interpretation: - a value > 1.40 suggests non-compressible artery (calcified) thus uninterpretable result* - a value of 1.0 to 1.4 is normal - a value of 0.91 to 0.99 is borderline - a value < 0.9 suggests peripheral vascular disease - a value < 0.4 is associated with ischemic pain at rest [1] - a decrease of 30% with an exercise ABI is diagnostic of peripheral arterial disease [1] * The elderly, & patients with diabetes or renal failure can have non-compressible vessels making ABIs invalid; however, toe pressures may be obtained. * A normal toe pressure is 80-100 mm Hg & a toe/brachial index of < 0.70 indicates peripheral arterial disease [1] * An exercise ankle-brachial index can be helpful if the value is borderline & pretest probability is high. It entails ABI measurements at rest & after walking on a treadmill. Plantar flexion exercises is an alternative. A post exercise ankle pressure drop of >= 30 mm Hg or significant decline in ABI is a positive test. * ABI may be be inaccurate & unreliable in the majority of patients with heel pressure injury [7]

Related

toe blood pressure

General

noninvasive vascular diagnostic study

References

  1. Medical Knowledge Self Assessment Program (MKSAP) 11, 14, 15, 16, 17, 19. American College of Physicians, Philadelphia 1998, 2006, 2009, 2012, 2015, 2022 - Medical Knowledge Self Assessment Program (MKSAP) 19 Board Basics. An Enhancement to MKSAP19. American College of Physicians, Philadelphia 2022
  2. Rooke TW et al 2011 ACCF/AHA Focused Update of the Guideline for the Management of Patients With Peripheral Artery Disease (Updating the 2005 Guideline): A Report of the American College of Cardiology Foundation/ American Heart Association Task Force on Practice Guidelines Circulation published online September 29, 2011 PMID: 21959305 http://circ.ahajournals.org/content/early/2011/09/29/CIR.0b013e31822e80c3 - Rooke TW, Hirsch AT, Misra S et al 2011 ACCF/AHA Focused Update of the Guideline for the Management of Patients With Peripheral Artery Disease (updating the 2005 guideline): a report of the American College of Cardiology Foundation/American Heart Association Task Force on Practice Guidelines. J Am Coll Cardiol. 2011 Nov 1;58(19):2020-45 PMID: 21963765
  3. de Liefde II, Klein J, Bax JJ et al Exercise ankle brachial index adds important prognostic information on long-term out-come only in patients with a normal resting ankle brachial index. PMID: 21397231
  4. Stein R, Hriljac I, Halperin JL et al Limitation of the resting ankle-brachial index in symptomatic patients with peripheral arterial disease. Vasc Med. 2006 Feb;11(1):29-33. PMID: 16669410
  5. 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):2890-909. PMID: 23159553
  6. Ankle Brachial Index Collaboration, Fowkes FG, Murray GD et al Ankle brachial index combined with Framingham Risk Score to predict cardiovascular events and mortality: a meta-analysis. JAMA. 2008 Jul 9;300(2):197-208 PMID: 18612117
  7. Crowell A, Meyr AJ Accuracy of the Ankle-Brachial Index in the Assessment of Arterial Perfusion of Heel Pressure Injuries. Wounds. 2017;29(2):51-55 (from Medscape) http://www.medscape.com/viewarticle/877804
  8. U.S. Preventive Services Task Force Draft Recommendation Statement Peripheral Artery Disease and Cardiovascular Disease: Screening and Risk Assessment With the Ankle-Brachial Index. https://www.uspreventiveservicestaskforce.org/Page/Document/draft-recommendation-statement/peripheral-artery-disease-in-adults-screening-with-the-ankle-brachial-index - U.S. Preventive Services Task Force Draft Evidence Review for Peripheral Artery Disease and Cardiovascular Disease: Screening and Risk Assessment With the Ankle-Brachial Index. https://www.uspreventiveservicestaskforce.org/Page/Document/draft-evidence-review/peripheral-artery-disease-in-adults-screening-with-the-ankle-brachial-index