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Ankle–brachial pressure index

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Ankle–brachial pressure index
Measuring the ankle-brachial index
SynonymsAnkle-brachial index
PurposeDetection ofperipheral artery disease

Theankle-brachial pressure index(ABPI) orankle-brachial index(ABI) is the ratio of theblood pressureat theankleto the blood pressure in theupper arm(brachium). Compared to the arm, lower blood pressure in the leg suggests blocked arteries due toperipheral artery disease(PAD). The ABPI is calculated by dividing thesystolicblood pressureat the ankle by the systolic blood pressure in the arm.[1]

Method

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The patient must be placed supine, without the head or any extremities dangling over the edge of the table. Measurement of ankle blood pressures in a seated position will grossly overestimate the ABI (by approximately 0.3).[citation needed]

ADoppler ultrasoundblood flow detector, commonly called Doppler wand or Doppler probe, and asphygmomanometer(blood pressure cuff) are usually needed. The blood pressure cuff is inflatedproximalto the artery in question. Measured by the Doppler wand, the inflation continues until the pulse in the artery ceases. The blood pressure cuff is then slowly deflated. When the artery's pulse is re-detected through the Doppler probe the pressure in the cuff at that moment indicates the systolic pressure of that artery.[citation needed] The higher systolic reading of the left and right armbrachial arteryis generally used in the assessment. The pressures in each foot'sposterior tibial arteryanddorsalis pedis arteryare measured with the higher of the two values used as the ABI for that leg.[2]

Where PLegis the systolic blood pressure of dorsalis pedis or posterior tibial arteries
and PArmis the highest of the left and right arm brachial systolic blood pressure

The ABPI test is a popular tool for the non-invasive assessment ofPeripheral vascular disease(PVD). Studies have shown thesensitivityof ABPI is 90% with a corresponding 98%specificityfor detectinghemodynamicallysignificant (stenosisof more than 50%) in major leg arteries, defined by angiogram.[3]

However, ABPI has known issues:

  • ABPI is known to be unreliable on patients with arterialcalcification(hardening of the arteries) which results in less or incompressible arteries,[4]as the stiff arteries produce falsely elevated ankle pressure, givingfalse negatives[5]). This is often found in patients withdiabetes mellitus[6](41% of patients withperipheral arterial disease(PAD) have diabetes[7]),kidney failureor heavysmokers.ABPI values below 0.9 or above 1.3 should be investigated further regardless.
  • Resting ABPI is insensitive to mild PAD.[8]Treadmill tests (6 minute) are sometimes used to increase ABPI sensitivity,[9]but this is unsuitable for patients who are obese or have co-morbidities such asAortic aneurysm,and increases assessment duration.
  • Lack of protocol standardisation,[10]which reduces intra-observer reliability.[11]
  • Skilled operators are required for consistent,accurateresults.[12]

When performed in an accredited diagnostic laboratory, the ABI is a fast, accurate, and painless exam, however these issues have rendered ABI unpopular in primary care offices and symptomatic patients are often referred to specialty clinics[13]due to the perceived difficulties. Technology is emerging that allows for the oscillometric calculation of ABI, in which simultaneous readings of blood pressure at the levels of the ankle and upper arm are taken using specially calibrated oscillometric machines.[citation needed]

Interpretation of results

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In a normal subject the pressure at the ankle is slightly higher than at the elbow (there is reflection of the pulse pressure from the vascular bed of the feet, whereas at the elbow the artery continues on some distance to the wrist).[citation needed]

The ABPI is the ratio of the highest ankle to brachial artery pressure. An ABPI between and including 0.90 and 1.29 considered normal (free from significantPAD), while a lesser than 0.9 indicates arterial disease.[14]An ABPI value of 1.3 or greater is also considered abnormal, and suggestscalcificationof the walls of the arteries and incompressible vessels, reflecting severeperipheral vascular disease.[citation needed]

Provided that there are no other significant conditions affecting the arteries of the leg, the following ABPI ratios can be used to predict the severity of PAD as well as assess the nature and best management of various types of legulcers.[2]Studies also indicate that the assessment of PAD in people with diabetes should use both ABPI ratios and Doppler waveforms.[15]

ABPI value Interpretation Action Nature ofulcers,if present
1.3 and above Abnormal
Vessel hardening fromPVD		 Refer or measureToe pressure Venous ulcer
use fullcompression bandaging
1.0 - 1.2 Normal range None
0.90 - 0.99 Acceptable
0.80 - 0.89 Some arterial disease Manage risk factors
0.50 - 0.79 Moderate arterial disease Routine specialist referral Mixed ulcers
use reduced compression bandaging
under 0.50 Severe arterial disease Urgent specialist referral Arterial ulcer
no compression bandaging used

Predictor of atherosclerosis mortality

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Studies in 2006 suggests that an abnormal ABPI may be an independent predictor of mortality, as it reflects the burden ofatherosclerosis.[16][17]It thus has potential for screening forcoronary artery disease,[18]although no evidence-based recommendations can be made about screening in low-risk patients because clinical trials are lacking.[18]It is noteworthy that abnormal values of ABI predispose to development ofthe frailty syndrome.[19]

See also

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References

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  1. ^Al-Qaisi, M; Nott, DM; King, DH; Kaddoura, S (2009)."Ankle brachial pressure index (ABPI): An update for practitioners".Vascular Health and Risk Management.5:833–41.doi:10.2147/vhrm.s6759.PMC2762432.PMID19851521.
  2. ^abVowden P, Vowden K (March 2001)."Doppler assessment and ABPI: Interpretation in the management of leg ulceration".Worldwide Wounds.- describes ABPI procedure, interpretation of results, and notes the somewhat arbitrary selection of "ABPI of 0.8 has become the accepted endpoint for high compression therapy, the trigger for referral for a vascular surgical opinion and the defining upper marker for an ulcer of mixed aetiology"
  3. ^McDermott MM, Criqui MH, Liu K, Guralnik JM, Greenland P, Martin GJ, Pearce W (December 2000)."Lower ankle/brachial index, as calculated by averaging the dorsalis pedis and posterior tibial arterial pressures, and association with leg functioning in peripheral arterial disease".J Vasc Surg.32(6): 1164–71.doi:10.1067/mva.2000.108640.PMID11107089.
  4. ^Allison MA,Hiatt WR,Hirsch AT, Coll JR, Criqui MH (April 2008). "A high ankle-brachial index is associated with increased cardiovascular disease morbidity and lower quality of life".J Am Coll Cardiol.51(13): 1292–8.doi:10.1016/j.jacc.2007.11.064.PMID18371562.
  5. ^American Diabetes Association (December 2003)."Peripheral Arterial Disease in People with Diabetes".Diabetes Care.26(12): 3333–3341.doi:10.2337/diacare.26.12.3333.PMID14633825.
  6. ^Aboyans V, Ho E, Denenberg JO, Ho LA, Natarajan L, Criqui MH (November 2008)."The association between elevated ankle systolic pressures and peripheral occlusive arterial disease in diabetic and nondiabetic subjects".J Vasc Surg.48(5): 1197–203.doi:10.1016/j.jvs.2008.06.005.PMID18692981.
  7. ^Novo S (March 2002). "Classification, epidemiology, risk factors, and natural history of peripheral arterial disease".Diabetes Obes Metab.4:S1–6.doi:10.1046/j.1463-1326.2002.0040s20s1.x.PMID12180352.S2CID321431.
  8. ^Stein R, Hriljac I,Halperin JL,Gustavson SM, Teodorescu V, Olin JW (February 2006)."Limitation of the resting ankle-brachial index in symptomatic patients with peripheral arterial disease"(PDF).Vasc Med.11(1): 29–33.doi:10.1191/1358863x06vm663oa.PMID16669410.S2CID12604550.
  9. ^Montgomery PS, Gardner AW (June 1998). "The clinical utility of a six-minute walk test in peripheral arterial occlusive disease patients".J Am Geriatr Soc.46(6): 706–11.doi:10.1111/j.1532-5415.1998.tb03804.x.PMID9625185.S2CID23527351.
  10. ^Jeelani NU, Braithwaite BD, Tomlin C, MacSweeney ST (July 2000)."Variation of method for measurement of brachial artery pressure significantly affects ankle-brachial pressure index values".Eur J Vasc Endovasc Surg.20(1): 25–8.doi:10.1053/ejvs.2000.1141.PMID10906293.
  11. ^Caruana MF, Bradbury AW, Adam DJ (May 2005)."The validity, reliability, reproducibility and extended utility of ankle to brachial pressure index in current vascular surgical practice".Eur J Vasc Endovasc Surg.29(5): 443–51.doi:10.1016/j.ejvs.2005.01.015.PMID15966081.
  12. ^Kaiser V, Kester AD, Stoffers HE, Kitslaar PJ, Knottnerus JA (July 1999)."The influence of experience on the reproducibility of the ankle-brachial systolic pressure ratio in peripheral arterial occlusive disease".Eur J Vasc Endovasc Surg.18(1): 25–9.doi:10.1053/ejvs.1999.0843.PMID10388635.
  13. ^Hirsch AT, Criqui MH, Treat-Jacobson D, Regensteiner JG, Creager MA, Olin JW, Krook SH, Hunninghake DB, Comerota AJ, Walsh ME, McDermott MM, Hiatt WR (Sep 2001). "Peripheral arterial disease detection, awareness, and treatment in primary care".JAMA.286(11): 1317–24.doi:10.1001/jama.286.11.1317.PMID11560536.
  14. ^Rooke, TW; Hirsch, AT; Misra, S; Sidawy, AN; Beckman, JA; Findeiss, LK; Golzarian, J; Gornik, HL; Halperin, JL; Jaff, MR; Moneta, GL; Olin, JW; Stanley, JC; White, CJ; White, JV; Zierler, RE; Society for Cardiovascular Angiography and, Interventions; Society of Interventional, Radiology; Society for Vascular, Medicine; Society for Vascular, Surgery (Nov 1, 2011)."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".Journal of the American College of Cardiology.58(19): 2020–45.doi:10.1016/j.jacc.2011.08.023.PMC4714326.PMID21963765.
  15. ^Formosa, Cynthia; Cassar, Kevin; Gatt, Alfred; Mizzi, Anabelle; Mizzi, Stephen; Camileri, Kenneth P.; Azzopardi, Carl; DeRaffaele, Clifford; Falzon, Owen; Cristina, Stefania; Chockalingam, Nachiappan (November 2013). "Hidden dangers revealed by misdiagnosed peripheral arterial disease using ABPI measurement".Diabetes Research and Clinical Practice.102(2): 112–116.doi:10.1016/j.diabres.2013.10.006.PMID24209599.
  16. ^Feringa HH, Bax JJ, van Waning VH, et al. (March 2006). "The long-term prognostic value of the resting and postexercise ankle-brachial index".Arch. Intern. Med.166(5): 529–35.doi:10.1001/archinte.166.5.529.PMID16534039.
  17. ^Wild SH, Byrne CD, Smith FB, Lee AJ, Fowkes FG (March 2006)."Low ankle-brachial pressure index predicts increased risk of cardiovascular disease independent of the metabolic syndrome and conventional cardiovascular risk factors in the Edinburgh Artery Study".Diabetes Care.29(3): 637–42.doi:10.2337/diacare.29.03.06.dc05-1637.PMID16505519.
  18. ^abDesai, Chintan S.; Blumenthal, Roger S.; Greenland, Philip (2014). "Screening low-risk individuals for coronary artery disease".Current Atherosclerosis Reports.16(4): 402.doi:10.1007/s11883-014-0402-8.ISSN1534-6242.PMID24522859.S2CID39392260.
  19. ^Jakubiak, Grzegorz K.; Pawlas, Natalia; Cieślar, Grzegorz; Stanek, Agata (January 2020)."Chronic Lower Extremity Ischemia and Its Association with the Frailty Syndrome in Patients with Diabetes".International Journal of Environmental Research and Public Health.17(24): 9339.doi:10.3390/ijerph17249339.PMC7764849.PMID33327401.
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