Ankle-Brachial Index Measurement

No Results

No Results

processing….

The ankle-brachial index (ABI) is an efficient tool for objectively documenting the presence of lower-extremity peripheral arterial disease (PAD). ^{[1, 2, 3, 4]} It is a simple, reproducible, and cost-effective assessment that can be used to detect lower-extremity arterial stenosis in the primary care setting, as well as to identify patients at increased risk for lower-extremity arterial injury after penetrating or blunt trauma.

An ABI less than 0.90 has been shown to have a sensitivity of 90% and a specificity of 98% for detecting a lower-extremity stenosis of greater than 50%. ^{[5, 6, 4]} In the trauma setting, an ABI less than 0.90 has been shown to have a sensitivity exceeding 87% and a specificity exceeding 97% for identifying lower-extremity arterial injury. ^[7]

Further information on the use of the ABI is available in the PAD management guidelines developed by the American College of Cardiology (ACC) and the American Heart Association (AHA).

In the primary care setting, an ABI is useful in the following 2 settings:

In a symptomatic patient, to diagnose PAD

In an asymptomatic patient, to assess the vascular risk for PAD

In the emergency or trauma setting, an ABI is useful for the evaluation of a patient who is at increased risk for lower-extremity arterial injury, ^[8] as follows:

An ABI less than 0.90 suggests a need for further vascular imaging: angiography in a stable patient, and operative exploration in an unstable patient

An ABI greater than 0.90 decreases the likelihood of an arterial injury; thus, the patient may be observed with serial ABI assessments or may undergo a vascular study on a delayed basis

Patients who are unable to remain supine for the duration of the examination are not candidates for an adequate ABI. ABI measurement is also contraindicated in a patient in whom the use of an occlusive sphygmomanometer cuff may worsen the extremity injury.

Necessary pieces of equipment for measurement of the ankle-brachial index (ABI) include the following:

An appropriately sized blood pressure cuff for the upper and lower extremities with a working sphygmomanometer

A Doppler device for detecting flow

Ultrasound transmission gel

An examination table

No anesthesia is recommended. Any form of sedative or anesthetic may affect the blood pressure measurement and thus reduce the accuracy of the ABI.

The patient should lie on an examination table in a supine position.

Different values obtained for the ankle-brachial index (ABI) are interpreted as follows: ^{[9, 10]}

0.00-0.40: Severe peripheral arterial disease (PAD) sufficient to cause resting pain or gangrene

0.41-0.90: PAD sufficient to cause claudication

0.91-1.30: Normal vessels

> 1.30: Noncompressible, severely calcified vessel

Patients with an ABI less than 0.90 have a higher risk of coronary artery disease, stroke, and death and therefore should be referred to a credentialed vascular laboratory for further testing. Such testing may include computed tomography (CT), magnetic resonance imaging (MRI), or conventional angiography, all of which involve injecting contrast material in order to assess the arterial flow. ^[4]

Claudication is a specific but not a sensitive finding in patients with PAD. One study stated that up to 90% of patients with a documented ABI of less than 0.90 did not report claudication as a symptom. ^{[11, 4, 10]}

An ABI of 0.91-0.99 is considered borderline. The patient may be asymptomatic at rest but may experience symptoms related to the compromised vascular flow when ambulating. An exercise test may help evaluate a patient who has borderline ABI results.

An incorrectly performed test may lead to a false negative or a false positive result and thereby delay the diagnosis or prompt unnecessary further testing. A false negative ABI result may occur in patients with noncompressible arteries—that is, a heavily calcified lower-extremity vessel may artificially elevate ankle pressure measurement.

Place the patient in the supine position, with the arms and legs at the same level as the heart, for a minimum of 10 minutes before measurement

Select an appropriately sized blood pressure cuff for both the ankle and the arms (see the images below); the cuff width should be, at a minimum, 20% greater than the diameter of the extremity. The ankle cuff should go on the leg between the malleolus and the calf. Enough room should be left below both cuffs to permit placement of the ultrasound gel, so that the Doppler device can adequately detect the brachial, dorsalis pedis, and posterior tibial pulses. ^{[4, 10]}

Obtain the brachial systolic pressures of both arms (see the images below), and choose the higher of the 2 values as the brachial systolic pressure (the difference between them should be less than 10 mm Hg). The brachial pulse is best appreciated on the medial side of the antecubital fossa.

Obtain the anterior tibial and posterior tibial systolic pressures of the extremity in question (see the images below), and select the higher of the 2 values as the ankle pressure measurement. The posterior tibial pulse is best appreciated just dorsal and inferior to the medial malleolus. The dorsalis pedis pulse is best appreciated on the dorsum of the foot between the proximal section of the first and second metatarsals, usually above the navicular bone.

Finally, divide the ankle pressure by the brachial artery pressure; the result is the ABI.

Lange SF, Trampisch HJ, Pittrow D, et al. Profound influence of different methods for determination of the ankle brachial index on the prevalence estimate of peripheral arterial disease. BMC Public Health. 2007. 7:147. [Medline].

Shanmugasundaram M, Ram VK, Luft UC, Szerlip M, Alpert JS. Peripheral arterial disease–what do we need to know?. Clin Cardiol. 2011 Aug. 34(8):478-82. [Medline].

Davies JH, Kenkre J, Williams EM. Current utility of the ankle-brachial index (ABI) in general practice: implications for its use in cardiovascular disease screening. BMC Fam Pract. 2014 Apr 17. 15:69. [Medline].

Rac-Albu M, Iliuta L, Guberna SM, Sinescu C. The role of ankle-brachial index for predicting peripheral arterial disease. Maedica (Buchar). 2014 Sep. 9(3):295-302. [Medline].

Yao ST, Hobbs JT, Irvine WT. Ankle systolic pressure measurements in arterial disease affecting the lower extremities. Br J Surg. 1969 Sep. 56(9):676-9. [Medline].

Ouriel K, McDonnell AE, Metz CE, Zarins CK. Critical evaluation of stress testing in the diagnosis of peripheral vascular disease. Surgery. 1982 Jun. 91(6):686-93. [Medline].

Johansen K, Lynch K, Paun M, Copass M. Non-invasive vascular tests reliably exclude occult arterial trauma in injured extremities. J Trauma. 1991 Apr. 31(4):515-9; discussion 519-22. [Medline].

Newton EJ, Arora S. Peripheral vascular injury. Marx JA. Marx: Rosen’s Emergency Medicine: Concepts and Clinical Practice. 7th ed. Philadelphia: Saunders Elsevier; 2009. Vol 1: Part II – Trauma.

Hiatt WR. Medical treatment of peripheral arterial disease and claudication. N Engl J Med. 2001 May 24. 344(21):1608-21. [Medline].

Bailey MA, Griffin KJ, Scott DJ. Clinical assessment of patients with peripheral arterial disease. Semin Intervent Radiol. 2014 Dec. 31(4):292-9. [Medline].

Hirsch AT, Criqui MH, Treat-Jacobson D, et al. Peripheral arterial disease detection, awareness, and treatment in primary care. JAMA. 2001 Sep 19. 286(11):1317-24. [Medline].

Sansosti LE, Berger MD, Gerrity MA, Kelly P, Meyr AJ. Effect of patient positioning on toe pressure measurement using noninvasive vascular testing. Br J Community Nurs. 2015 Sep. Suppl Wound Care:S12, S14-6. [Medline].

Saber R, Liu K, Ferrucci L, et al. Ischemia-related changes in circulating stem and progenitor cells and associated clinical characteristics in peripheral artery disease. Vasc Med. 2015 Dec. 20(6):534-43. [Medline].

Husmann M, Jacomella V, Thalhammer C, Amann-Vesti BR. Markers of arterial stiffness in peripheral arterial disease. Vasa. 2015 Sep. 44(5):341-8. [Medline].

Ferket BS, Spronk S, Colkesen EB, Hunink MG. Systematic review of guidelines on peripheral artery disease screening. Am J Med. 2012. 125 (2):198. [Medline].

Chan W Park, MD, FAAEM Adjunct Assistant Professor, Division of Emergency Medicine, Duke University Medical Center; Director of Simulation Medicine, Durham Veterans Affairs Medical Center

Chan W Park, MD, FAAEM is a member of the following medical societies: American Academy of Emergency Medicine, American College of Emergency Physicians, Society for Academic Emergency Medicine

Disclosure: Nothing to disclose.

Kevin Scott Koehler, MD Resident Physician, Department of Emergency Medicine, Naval Medical Center Portsmouth

Disclosure: Nothing to disclose.

Steven C Romero, MD Staff Cardiologist, Naval Medical Center San Diego

Steven C Romero, MD is a member of the following medical societies: American College of Cardiology, American Society of Echocardiography

Disclosure: Nothing to disclose.

Mary L Windle, PharmD Adjunct Associate Professor, University of Nebraska Medical Center College of Pharmacy; Editor-in-Chief, Medscape Drug Reference

Disclosure: Nothing to disclose.

Karlheinz Peter, MD, PhD Professor of Medicine, Monash University; Head of Centre of Thrombosis and Myocardial Infarction, Head of Division of Atherothrombosis and Vascular Biology, Associate Director, Baker Heart Research Institute; Interventional Cardiologist, The Alfred Hospital, Australia

Karlheinz Peter, MD, PhD is a member of the following medical societies: American Heart Association, German Cardiac Society, Cardiac Society of Australia and New Zealand

Disclosure: Nothing to disclose.

The authors would like to thank the Naval Medical Center Portsmouth for its contributions, as well as the staff of this facility. Most importantly, the authors would like to thank the Corpsmen of the United States Navy, the Emergency Department Corpsmen, and HM1 Lee for his contributions as a leg and arm model.

Ankle-Brachial Index Measurement

Research & References of Ankle-Brachial Index Measurement|A&C Accounting And Tax Services
Source

Share on Facebook

Tweet

Follow us