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| The '''Ankle Brachial Index''' ('''ABI''') is the ratio of the [[blood pressure]] in the lower legs to the blood pressure in the arms. Compared to the arm, lower blood pressure in the leg is an [[indication (medicine)|indication]] of blocked arteries ([[peripheral vascular disease]] or PVD). The ABI is calculated by dividing the [[Systole (medicine)|systolic]] [[blood pressure]] at the ankle by the systolic blood pressures in the arm.<ref name=Review09>{{cite journal|last=Al-Qaisi|first=M|coauthors=Nott, DM, King, DH, Kaddoura, S|title=Ankle brachial pressure index (ABPI): An update for practitioners.|journal=Vascular health and risk management|year=2009|volume=5|pages=833–41|pmid=19851521|pmc=2762432}}</ref>
| | Andrew Simcox is the title his parents gave him and he completely enjoys this name. Her family members lives in Ohio. Office supervising is where my main income comes from but I've always wanted my personal business. The favorite hobby for him and his kids is fashion and he'll be beginning some thing else alongside with it.<br><br>my homepage - [http://checkmates.co.za/index.php?do=/profile-56347/info/ tarot readings] |
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| ==Method==
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| A [[Medical_ultrasonography#Doppler_sonography|Doppler ultrasound]] blood flow detector, commonly called Doppler Wand or Doppler probe, and a [[sphygmomanometer]] (blood pressure cuff) are usually needed. The blood pressure cuff is inflated [[Anatomical terms of location#Proximal and distal|proximal]] to 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.
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| The higher systolic reading of the left and right arm [[brachial artery]] is generally used in the assessment. The pressures in each foot's [[posterior tibial artery]] and [[dorsalis pedis artery]] are measured with the higher of the two values used as the ABI for that leg.<ref name="Vowden">{{cite journal |author=Vowden P, Vowden K |title=Doppler assessment and ABPI: Interpretation in the management of leg ulceration |journal=Worldwide Wounds |date=March 2001 |url=http://www.worldwidewounds.com/2001/march/Vowden/Doppler-assessment-and-ABPI.html}} - 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"</ref> | |
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| :<math>ABPI_{Leg} = \frac { P_{Leg} }{ P_{Arm} }</math>
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| ::Where P<sub>Leg</sub> is the systolic blood pressure of dorsalis pedis or posterior tibial arteries
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| ::and P<sub>Arm</sub> is the highest of the left and right arm brachial systolic blood pressure
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| The ABPI test is a popular tool for the non-invasive assessment of [[Peripheral vascular disease|PVD]]. Studies have shown the [[sensitivity and specificity|sensitivity]] of ABPI is 90% with a corresponding 98% [[sensitivity and specificity|specificity]] for detecting [[hemodynamics|hemodynamically]] significant (Serious) [[stenosis]] >50% in major leg arteries, defined by angiogram.<ref>{{cite journal |author=McDermott MM, Criqui MH, Liu K, Guralnik JM, Greenland P, Martin GJ, Pearce W |title=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 |journal=JJ Vasc Surg. |volume=32 |issue=6 |pages=1164–71 |date=December 2000 |pmid=11107089 |doi=10.1067/mva.2000.108640 }}</ref>
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| However, ABPI has known issues:
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| *ABPI is known to be unreliable on patients with arterial [[calcification]] ([[hardening of the arteries]]) which results in less or incompressible arteries,<ref>{{cite journal |author=Allison MA, Hiatt WR, Hirsch AT, Coll JR, Criqui MH |title=A high ankle-brachial index is associated with increased cardiovascular disease morbidity and lower quality of life |journal=J Am Coll Cardiol.|volume=51 |issue=13 |pages=1292–8 |date=April 2008|pmid=18371562 |doi=10.1016/j.jacc.2007.11.064 }}</ref> as the stiff arteries produce falsely elevated ankle pressure, giving [[false negative]]s<ref>{{cite journal |author=American Diabetes Association|title=Peripheral Arterial Disease in People with Diabetes| journal=Diabetes Care|volume=26|issue=12|pages=3333–3341 |date=December 2003|pmid=14633825 |doi=10.2337/diacare.26.12.3333 }}</ref>). This is often found in patients with [[diabetes mellitus]]<ref>{{cite journal |author=Aboyans V, Ho E, Denenberg JO, Ho LA, Natarajan L, Criqui MH |title=The association between elevated ankle systolic pressures and peripheral occlusive arterial disease in diabetic and nondiabetic subjects | journal=J Vasc Surg.|volume=48|issue=5|pages=1197–203 |date=November 2008|pmid=18692981 |doi=10.1016/j.jvs.2008.06.005 }}</ref> (41% of patients with [[peripheral arterial disease]] (PAD) have diabetes<ref>{{cite journal |author=Novo S|title=Classification, epidemiology, risk factors, and natural history of peripheral arterial disease| journal=Diabetes Obes Metab.|volume=4|supplement=2|pages=S1–6 |date=March 2002|pmid=12180352 |doi=10.1046/j.1463-1326.2002.0040s20s1.x }}</ref>), [[renal failure]] or heavy [[tobacco smoking|smoker]]s. ABPI values < 0.9 & >1.3 should be investigated further regardless.
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| *Resting ABPI is insensitive to mild PAD.<ref>{{cite journal |author=Stein R, Hriljac I, [[Jonathan L. Halperin|Halperin JL]], Gustavson SM, Teodorescu V, Olin JW |title=Limitation of the resting ankle-brachial index in symptomatic patients with peripheral arterial disease | journal=J Vasc Med.|volume=11|issue=1|pages=29–33 |date=February 2006|pmid=16669410 |doi=10.1191/1358863x06vm663oa }}</ref> Treadmill tests (6 minute) are sometimes used to increase ABPI sensitivity,<ref>{{cite journal |author=Montgomery PS, Gardner AW,|title=The clinical utility of a six-minute walk test in peripheral arterial occlusive disease patients | journal=J Am Geriatr Soc |volume=46|issue=6|pages=706–11|date=June 1998|pmid=9625185 }}</ref> but this is unsuitable for patients who are obese or have co-morbidities such as [[Aortic aneurysm]], and increases assessment duration.
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| *Lack of protocol standardisation,<ref>{{cite journal |author=Jeelani NU, Braithwaite BD, Tomlin C, MacSweeney ST|title=Variation of method for measurement of brachial artery pressure significantly affects ankle-brachial pressure index values| journal=Eur J Vasc Endovasc Surg.|volume=20|issue=1|pages=25–8|date=July 2000|pmid=10906293 |doi=10.1053/ejvs.2000.1141 }}</ref> which reduces intra-observer reliability.<ref>{{cite journal |author=Caruana MF, Bradbury AW, Adam DJ|title=The validity, reliability, reproducibility and extended utility of ankle to brachial pressure index in current vascular surgical practice| journal=Eur J Vasc Endovasc Surg.|volume=29|issue=5|pages=443–51|date=May 2005|pmid=15966081 |doi=10.1016/j.ejvs.2005.01.015}}</ref>
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| *Skilled operators are required for consistent, [[accurate]] results.<ref>{{cite journal |author=Kaiser V, Kester AD, Stoffers HE, Kitslaar PJ, Knottnerus JA|title=The influence of experience on the reproducibility of the ankle-brachial systolic pressure ratio in peripheral arterial occlusive disease| journal=Eur J Vasc Endovasc Surg.|volume=18|issue=1|pages=25–9|date=July 1999|pmid=10388635 |doi=10.1053/ejvs.1999.0843 }}</ref>
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| When performed in an accredited lab, 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<ref>{{cite journal |author=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.
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| |title=Peripheral arterial disease detection, awareness, and treatment in primary care.
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| | journal=JAMA|volume=19|issue=286|pages=1317–24|date=Sep 2001|pmid=11560536|doi=10.1001/jama.286.11.1317}}</ref> 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.
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| ==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).
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| The ABPI is the ratio of the highest ankle to brachial artery pressure. An ABPI between 0.9 and 1.2 considered normal (free from significant [[Peripheral artery occlusive disease|PAD]]), while a lesser than 0.9 indicates arterial disease. An ABPI value greater than 1.3 is also considered abnormal, and suggests [[calcification]] of the walls of the arteries and incompressible vessels, reflecting severe [[peripheral vascular disease]].
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| 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 leg [[Skin ulcer|ulcers]]:<ref name="Vowden" />
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| {| class="wikitable"
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| !ABPI value || Interpretation || Action || Nature of [[Ulcer (dermatology)|ulcers]], if present
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| | above 1.2 || Abnormal<br/>Vessel hardening from PVD || Refer routinely || rowspan="4" | [[Venous ulcer]]<br/>use full [[Bandage#Compression bandage|compression bandaging]]
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| | 1.0 - 1.2 || Normal range || rowspan="2" | None
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| | 0.9 - 1.0 || Acceptable
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| | 0.8 - 0.9 || Some arterial disease || Manage risk factors
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| | 0.5 - 0.8 || Moderate arterial disease || Routine specialist referral || Mixed ulcers<br/>use reduced compression bandaging
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| | under 0.5 || Severe arterial disease || Urgent specialist referral || Arterial ulcers<br/>no compression bandaging used
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| |}
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| ==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 of [[atherosclerosis]].<ref name="pmid16534039">{{cite journal |author=Feringa HH, Bax JJ, van Waning VH, ''et al.'' |title=The long-term prognostic value of the resting and postexercise ankle-brachial index |journal=Arch. Intern. Med. |volume=166 |issue=5 |pages=529–35 |date=March 2006 |pmid=16534039 |doi=10.1001/archinte.166.5.529 |url=}}</ref><ref name="pmid16505519">{{cite journal |author=Wild SH, Byrne CD, Smith FB, Lee AJ, Fowkes FG |title=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 |journal=Diabetes Care |volume=29 |issue=3 |pages=637–42 |date=March 2006 |pmid=16505519 |doi= 10.2337/diacare.29.03.06.dc05-1637|url=http://care.diabetesjournals.org/cgi/content/full/29/3/637}}</ref>
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| ==See also==
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| *[[Peripheral vascular disease]]
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| *[[Peripheral vascular examination]]
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| *[[Intermittent claudication]]
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| ==References==
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| {{reflist|2}}
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| {{Physical exam}}
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| {{Vascular procedures}}
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| {{DEFAULTSORT:Ankle Brachial Pressure Index}}
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| [[Category:Cardiovascular physiology]]
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| [[Category:Physical examination]]
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| [[Category:Medical ultrasonography]]
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Andrew Simcox is the title his parents gave him and he completely enjoys this name. Her family members lives in Ohio. Office supervising is where my main income comes from but I've always wanted my personal business. The favorite hobby for him and his kids is fashion and he'll be beginning some thing else alongside with it.
my homepage - tarot readings