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Ankle brachial index for the diagnosis of lower limb peripheral arterial disease

  • Review
  • Diagnostic

Authors


Abstract

Background

Peripheral arterial disease (PAD) of the lower limb is common, with prevalence of both symptomatic and asymptomatic disease estimated at 13% in the over 50 age group. Symptomatic PAD affects about 5% of individuals in Western populations between the ages of 55 and 74 years. The most common initial symptom of PAD is muscle pain on exercise that is relieved by rest and is attributed to reduced lower limb blood flow due to atherosclerotic disease (intermittent claudication). The ankle brachial index (ABI) is widely used by a variety of healthcare professionals, including specialist nurses, physicians, surgeons and podiatrists working in primary and secondary care settings, to assess signs and symptoms of PAD. As the ABI test is non-invasive and inexpensive and is in widespread clinical use, a systematic review of its diagnostic accuracy in people presenting with leg pain suggestive of PAD is highly relevant to routine clinical practice.

Objectives

To estimate the diagnostic accuracy of the ankle brachial index (ABI) - also known as the ankle brachial pressure index (ABPI) - for the diagnosis of peripheral arterial disease in people who experience leg pain on walking that is alleviated by rest.

Search methods

We carried out searches of the following databases in August 2013: MEDLINE (Ovid SP),Embase (Ovid SP), the Cumulative Index to Nursing and Allied Health Literature (CINAHL) (EBSCO), Latin American and Caribbean Health Sciences (LILACS) (Bireme), Database of Abstracts of Reviews of Effects and the Health Technology Assessment Database in The Cochrane Library, the Institute for Scientific Information (ISI) Conference Proceedings Citation Index - Science, the British Library Zetoc Conference search and Medion.

Selection criteria

We included cross-sectional studies of ABI in which duplex ultrasonography or angiography was used as the reference standard. We also included cross-sectional or diagnostic test accuracy (DTA) cohort studies consisting of both prospective and retrospective studies.

Participants were adults presenting with leg pain on walking that was relieved by rest, who were tested in primary care settings or secondary care settings (hospital outpatients only) and who did not have signs or symptoms of critical limb ischaemia (rest pain, ischaemic ulcers or gangrene).

The index test was ABI, also called the ankle brachial pressure index (ABPI) or the Ankle Arm Index (AAI), which was performed with a hand-held doppler or oscillometry device to detect ankle vessels. We included data collected via sphygmomanometers (both manual and aneroid) and digital equipment.

Data collection and analysis

Two review authors independently replicated data extraction by using a standard form, which included an assessment of study quality, and resolved disagreements by discussion. Two review authors extracted participant-level data when available to populate 2×2 contingency tables (true positives, true negatives, false positives and false negatives).

After a pilot phase involving two review authors working independently, we used the methodological quality assessment tool the Quality Assessment of Diagnostic Accuracy Studies-2 (QUADAS-2), which incorporated our review question - along with a flow diagram to aid reviewers' understanding of the conduct of the study when necessary and an assessment of risk of bias and applicability judgements.

Main results

We screened 17,055 records identified through searches of databases. We obtained 746 full-text articles and assessed them for relevance. We scrutinised 49 studies to establish their eligibility for inclusion in the review and excluded 48, primarily because participants were not patients presenting solely with exertional leg pain, investigators used no reference standard or investigators used neither angiography nor duplex ultrasonography as the reference standard. We excluded most studies for more than one reason.

Only one study met the eligibility criteria and provided limb-level accuracy data from just 85 participants (158 legs). This prospective study compared the manual doppler method of obtaining an ABI (performed by untrained personnel) with the automated oscillometric method. Limb-level data, as reported by the study, indicated that the accuracy of the ABI in detecting significant arterial disease on angiography is superior when stenosis is present in the femoropopliteal vessels, with sensitivity of 97% (95% confidence interval (CI) 93% to 99%) and specificity of 89% (95% CI 67% to 95%) for oscillometric ABI, and sensitivity of 95% (95% CI 89% to 97%) and specificity of 56% (95% CI 33% to 70%) for doppler ABI. The ABI threshold was not reported. Investigators attributed the lower specificity for doppler to the fact that a tibial or dorsalis pedis pulse could not be detected by doppler in 12 of 27 legs with normal vessels or non-significant lesions. The superiority of the oscillometric (automated) method for obtaining an ABI reading over the manual method with a doppler probe used by inexperienced operators may be a clinically important finding.

Authors' conclusions

Evidence about the accuracy of the ankle brachial index for the diagnosis of PAD in people with leg pain on exercise that is alleviated by rest is sparse. The single study included in our review provided only limb-level data from a few participants. Well-designed cross-sectional studies are required to evaluate the accuracy of ABI in patients presenting with early symptoms of peripheral arterial disease in all healthcare settings. Another systematic review of existing studies assessing the use of ABI in alternative patient groups, including asymptomatic, high-risk patients, is required.

Plain language summary

Ankle brachial index for the diagnosis of lower limb peripheral arterial disease

Peripheral arterial disease (PAD) of the legs affects 13% of people over 50 years of age. Sometimes PAD is "silent" and people are unaware they have it, but PAD can cause pain in the legs, especially with walking, and this type of symptomatic PAD affects about 5% of people in the Western world between the ages of 55 and 74 years. In PAD, fatty deposits (atherosclerosis) and blood clots cause the arteries to narrow and block. This leads to poor blood flow to the muscles during exercise, causing the classical symptom of muscle pain during walking that goes away after rest (intermittent claudication). In severe cases of PAD, symptoms of rest pain, ulceration and gangrene may develop and, if untreated, can lead to lower limb amputation. People with PAD are also at higher risk for cardiovascular disease and stroke.

The ankle brachial index (ABI) is a test that is used to facilitate diagnosis of PAD. This test uses a device for measuring blood pressure with an inflatable cuff, and blood pressure measurements are taken at the upper arm and the ankle. The equipment can be manual or digital with automatic electronic calculation of blood pressure. The ABI is widely used for assessment of PAD by specialist nurses, physicians, surgeons and podiatrists working in hospitals. Dividing blood pressure recorded at the ankle by that recorded at the arm produces a ratio. Ratios of 0.90 to 1.30 are considered normal for adults, and ratios less than 0.8 indicate that PAD is present. Lower readings (< 0.7) suggest that the disease is severe and people might develop ulcers and gangrene. People with mild to moderate PAD can arrive at a diagnosis by several routes when using the ABI: during routine diabetic foot checks in general practice, in community health clinic or hospital settings, as a screening test for PAD in people who have no symptoms and during assessment of people presenting with exertional leg pain suggestive of PAD. Once a diagnosis of PAD is established, treatment will include prescribed secondary prevention therapy and lifestyle advice (exercise, smoking cessation, diet, weight), and for those with impaired quality of life, treatment may include supervised exercise therapy, or revascularisation, which commonly involves endovascular treatment rather than surgery.

In hospitals, other tests may be used to diagnose PAD. Duplex ultrasound (DUS) shows blood flow in the arteries and is non-invasive, but only an experienced radiologist can achieve useful images. Hospital staff can use other tests to image the blood vessels, namely, computerised tomography angiography (CTA), magnetic resonance angiography (MRA) and catheter angiography.

The ABI test is non-invasive and inexpensive and is widely used clinically; therefore, we have reviewed all available reports obtained from a wide search of databases of medical literature to estimate its accuracy in identifying PAD in people who experience pain on walking that goes away after rest. Two review authors independently assessed studies that met inclusion criteria of the review, including use of a cross-sectional study design; enrolment of participants with pain on walking that got better with rest; and use of duplex ultrasonography or angiography to check that results of the ABI test were accurate. One study met our criteria and provided data from 85 participants (158 limbs). Investigators compared the manual doppler method of measuring ABI with the automated method. Researchers provided only data for legs as opposed to data for patients; we were therefore unable to recalculate the analysis at the whole-participant level.

In conclusion, we found little evidence about the accuracy of the ankle brachial index for diagnosing PAD in people presenting with exertional leg pain. The study included in our review had some flaws, and well-designed cross-sectional studies are needed to measure the accuracy of the ABI for diagnosing PAD in patients with early symptoms.

Laički sažetak

Brahijalni indeks gležnja za dijagnosticiranje bolesti perifernih arterija nogu

Periferna arterijska bolest (engl. peripheral arterial disease, PAD) nogu pogađa 13% osoba starijih od 50 godina. PAD je ponekad "tiha bolest", i ljudi nisu svjesni da je imaju, ali ponekad može uzrokovati i bol u nogama, posebno tijekom hodanje. Ta vrsta simptomatske bolesti pogađa oko 5% ljudi u zapadnom svijetu u dobi između 55 i 74 godina. PAD nastaje tako što masne naslage (ateroskleroza) i krvni ugrušci uzrokuju sužavanje i blokiranje arterija. To dovodi do lošeg protoka krvi kroz mišiće tijekom tjelesne aktivnosti, što uzrokuje ozbiljne simptome bolova u mišićima tijekom hodanja koji nestaju nakon odmora (privremeno šepanje; intermitentna klaudikacija). U teškim slučajevima PAD-a mogu se pojaviti simptomi boli tijekom odmora, rane na koži (ulceracije) i gangrena, a ako se ne liječi, može dovesti do amputacije nogu. Osobe koje pate od PAD-a također imaju veći rizik za srčano-žilne bolesti i moždani udar.

Brahijalni indeks gležnja (engl.ankle brachial index, ABI) je test koji se koristi za olakšavanje dijagnoze PAD. Za taj se test koristi uređaj koji mjeri krvni tlak uz napuhavanje manšete, te se uzimaju mjerenja krvnog tlaka na gornjoj nadlaktici i gležnju. Uređaj može imati ručno ili digitalno upravljanje s automatskim elektronskim izračunom krvnog tlaka. ABI često koriste specijalizirane medicinske sestre, liječnici, kirurzi i podijatristi koji rade u bolnicama za procjenu težine PAD-a. Kad se podijeli vrijednost krvnog tlaka zabilježenog na gležnju s vrijednošću koja je zabilježena na ruci dobiva se omjer. Smatra se da su omjeri između 0,90-1,30 za odrasle normalni, dok omjeri manji od 0,8 ukazuju na to da je PAD prisutan. Niže vrijednosti (<0,7) ukazuju na to da je bolest teška te da ti bolesnici mogu razviti ulceracije i gangrenu. U osoba s blagom do umjerenom bolesti PAD može se postaviti dijagnoza na nekoliko načina uz uporabu ABI: tijekom rutinskih provjera dijabetičkog stopala u općoj praksi, u javnim zdravstvenim klinikama i bolnicama, tijekom testa probira na PAD kod ljudi koji nemaju simptoma, te tijekom procjene ljudi kod kojih se pojavljuje bol u nogama uslijed napora, a koja ukazuju na PAD. Nakon što se uspostavi dijagnoza PAD-a, liječenje uključuje ​​propisanu sekundarnu preventivnu terapiju i savjete za zdraviji život (vježbanje, prestanak pušenja, prehrana, težina). Za osobe s narušenom kvalitetom života, liječenje može uključivati vježbanje uz nadzor, terapiju, ili revaskularizaciju, koja obično uključuje endovaskularni postupak, a rjeđe operaciju.

U bolnicama se i drugi testovi mogu koristiti za dijagnosticiranje PAD-a. Duplex ultrazvuk (engl. duplex ultrasound, DUS) je neinvazivna tehnika koja pokazuje protok krvi u arterijama, međutim samo iskusni radiolog može postići korisne slike. Bolničko osoblje može koristiti i druge testove kako bi se dobile slike krvnih žila, poimenice to su angiografija s kompjuteriziranom tomografijom (engl. computerised tomography angiography, CTA), magnetska rezonantna angiografija (engl. magnetic resonance angiography, MRA) i kateter angiografija.

ABI test je neinvazivna, jeftina metoda koja se široko koristi u kliničkoj praksi. Stoga su istraživači u ovom Cochrane sustavnom pregledu literature analizirali sve dostupne znanstvene radove dobivene opsežnim pretraživanjem baze podataka medicinske literature kako bi procijenili točnost ABI testa u otkrivanju PAD-a u osoba koje osjećaju bol tijekom hodanja, a koja nestaje nakon odmora. Dva autora su samostalno ocijenili studije koje zadovoljavaju kriterije uključivanja u pregled, uključujući presječna istraživanja; uključivanje sudionika koji osjećaju bol tijekom hodanja, i koji se osjećaju bolje nakon odmora; te uporabu duplex ultrazvuka ili angiografije kako bi se provjerila točnost rezultata ABI testa. Jedna studija je zadovoljila naše kriterije. To istraživanja sadrži podatke dobivene od 85 sudionika (158 udova). Istraživači su usporedili ručnu dopler metodu mjerenja vrijednosti ABI s automatskom metodom. Međutim, istraživači su prikazali samo podatke za noge, a ne podatke za bolesnike; stoga nije bilo moguće preračunati analizu na razini jednoga sudionika.

Zaključno, pronašli smo malo dokaza o točnosti brahijalnog indeksa gležnja za dijagnosticiranje periferne arterijske bolesti u osoba s boli u nogama uslijed napora. Studija uključena u naš pregled literature imala je neke nedostatke, te smatramo da je potrebno provesti dobro dizajnirana presječna istraživanja kako bi se odredila točnost ABI za dijagnosticiranje bolesti PAD u bolesnika s ranim simptomima.

Bilješke prijevoda

Hrvatski Cochrane
Prevela: Jasna Safić
Ovaj sažetak preveden je u okviru volonterskog projekta prevođenja Cochrane sažetaka. Uključite se u projekt i pomozite nam u prevođenju brojnih preostalih Cochrane sažetaka koji su još uvijek dostupni samo na engleskom jeziku. Kontakt: cochrane_croatia@mefst.hr

Ringkasan bahasa mudah

Indeks brakial buku lali untuk diagnosis penyakit arteri periferi kaki

Penyakit arteri periferi (PAD) pada kaki mempengaruhi 13% orang yang berumur 50 tahun ke atas. Kadangkala PAD adalah "senyap" dan orang tidak sedar yang mereka menghidapnya, tetapi PAD boleh menyebabkan sakit di kaki, terutamanya ketika berjalan, dan jenis PAD dengan gejala ini mempengaruhi 5% orang di dunia Barat di antara umur 55 hingga 74 tahun. Berkenaan PAD, deposit lemak (aterosklerosis) dan darah beku menyebabkan arteri-arteri menjadi sempit dan tersumbat. Ini menyebabkan aliran darah yang lemahkepada otot-otot ketika bersenam, mengakibatkan gejala klasik sakit otot ketika berjalan yang reda selepas berehat (klaudikasi terputus-putus). Dalam kes-kes PAD yang teruk, gejala sakit ketika berehat, ulser dan gangren boleh terbentuk dan, jika tidak dirawat, boleh mengakibatkan amputasi kaki. Orang yang menghidap PAD juga berisiko tinggi untuk penyakit kardiovaskular dan strok.

Indeks brakial buku lali (ABI) adalah ujian yang digunakan untuk memudahkan diagnosis PAD. Ujian tersebut diguna untuk menyukat tekanan darah menggunakan kaf yang boleh kembung, dan ukuran tekanan darah diambil pada pangkal lengan dan buku lali. Alat tersebut boleh secara manual atau digital menggunakan pengiraan tekanan darah elektronik otomatik. ABI tersebut digunakan secara meluas untuk pemeriksaan PAD oleh jururawat pakar, doktor, doktor bedah dan 'podiatrist' di hospital-hospital. Membahagikan tekanan darah yang direkodkan di buku lali kepada tekanan yang direkod di lengan menghasilkan satu nisbah. Nisbah 0.90 sehingga 1.30 dianggap normal untuk dewasa, dan nisbah kurang dari 0.8 menunjukkan terdapat PAD. Bacaan yang lebih rendah (<0.7) mencadangkan bahawa penyakit tersebut adalah teruk dan orang mungkin boleh mendapat ulser dan gangren. Orang yang mempunyai PAD ringan dan sederhana boleh didiagnos melalui beberapa cara apabila menggunakan ABI: ketika pemeriksaan rutin kaki diabetik di praktis umum, di klinik kesihatan komuniti atau persekitaran hospital, sebagai ujian saringan PAD dalam kalangan orang yang tidak mempunyai gejala dan semasa pemeriksaan orang yang mempunyai sakit kaki ketika bergerak menunjukkan PAD. Apabila diagnosis PAD dibuat, rawatan akan melibatkan terapi pencegahan sekunder dan nasihat gaya hidup (senaman, berhenti merokok, pemakanan, berat), dan untuk mereka dengan kualiti hidup yang terjejas, rawatan melibatkan terapi senaman di bawah pengawasan, atau vaskularisasi semula, yang biasanya melibatkan rawatan endovaskular berbanding pembedahan.

Di hospital-hospital, ujian-ujian lain mungkin digunakan untuk mendiagnos PAD. Ultrasound Dupleks (DUS) meunjukkan aliran darah dalam arteri-arteri dan ianya tidak invasif, tetapi hanya ahli radiologi berpengalaman boleh menghasilkan imej-imej yang berguna. Staf hospital boleh menggunakan ujian-ujian lain untuk mendapatkan imej saluran darah, iaitu, angiografi tomografi berkomputer (CTA), angiografi resonan magnetik (MRA) dan angiografi kateter.

Ujian ABI adalah tidak invasif dan tidak mahal dan diguna secara klinikal dengan meluas; oleh itu, kami telah mengulas semua laporan sedia ada daripada pencarian meluas pangkalan data penulisan perubatan untuk menganggarkan ketepatan mengenalpasti PAD dalam kalangan orang yang mengalami sakit ketika berjalan dan hilang sakit apabila rehat. Dua penulis bebas ulasan menilai kajian-kajian yang menepati kriteria kemasukan ulasan, termasuk penggunaan reka bentuk kajian keratan rentas; enrolmen peserta yang sakit ketika berjalan dan reda dengan berehat; dan penggunaan ultrasonografi dupleks atau angiografi untuk memeriksa kejituan keputusan-keputusan ABI. Satu kajian menepati kriteria kami dan memberikan data daripada 85 peserta (158 anggota badan). Penyiasat membandingkan kaedah dopler manual mengukur ABI dengan kaedah otomatik. Penyelidik-penyelidik hanya memberikan data untuk kaki-kaki berbanding data untuk pesakit; oleh itu kami tidak dapat mengira semula analisis di tahap keseluruhan pesakit.

Kesimpulannya, kami hanya menjumpai bukti yang sedikit mengenai kejituan indeks brakial buku lali untuk diagnosis PAD dalam kalangan orang yang mengalami sakit kaki ketika ada tekanan. Kajian yang dimasukkan dalam ulasan kami mempunyai beberapa kelemahan, dan kajian keratan rentas yang bermutu diperlukan untuk mengukur kejituan ABI bagi mendiagnos PAD dalam pesakit yang mempunyai gejala awal.

Catatan terjemahan

Diterjemahkan oleh Tuan Hairulnizam Tuan Kamauzaman (Universiti Sains Malaysia). Untuk sebarang pertanyaan mengenai terjemahan ini sila hubungi hairulnizam@usm.my. Disunting oleh Noorliza Mastura Ismail (Kolej Perubatan Melaka-Manipal).