Elsevier

Atherosclerosis

Volume 189, Issue 1, November 2006, Pages 61-69
Atherosclerosis

Review
Risk of mortality and cardiovascular disease associated with the ankle-brachial index: Systematic review

https://doi.org/10.1016/j.atherosclerosis.2006.03.011Get rights and content

Abstract

Objective

To determine the strength and consistency with which a low ankle brachial pressure index (ABI), measured in the general population, is associated with an increased risk of subsequent death and/or cardiovascular events.

Data sources

Medline, Embase, reference lists and grey literature were searched; studies known to experts were also retrieved.

Main outcome measures

All cause mortality, fatal and non-fatal coronary heart disease and stroke.

Review methods

Longitudinal studies in which participants were representative of the general population (all ages, either sex) and which used any standard method for measurement and calculation of the ABI. Studies in which participants were selected according to presence of pre-existing disease or were post intervention (e.g. angioplasty or peripheral arterial grafting) were excluded.

Results

11 studies comprising 44,590 subjects from six different countries were included. Despite clinical heterogeneity between studies, the findings were remarkably consistent in demonstrating an increased risk of clinical cardiovascular disease associated with a low ABI. A low ABI (<0.9) was associated with an increased risk of subsequent all cause mortality (pooled RR 1.60, 95% CI 1.32–1.95), cardiovascular mortality (pooled RR 1.96, 95% CI 1.46–2.64), coronary heart disease (pooled RR 1.45, 95% CI 1.08–1.93) and stroke (pooled RR 1.35, 95% CI 1.10–1.65) after adjustment for age, sex, conventional cardiovascular risk factors and prevalent cardiovascular disease.

Conclusions

The ABI may help to identify asymptomatic individuals in the general population who are at increased risk of subsequent cardiovascular events. Evaluation is now required of the potential of incorporating ABI measurement into cardiovascular prevention programmes.

Introduction

Cardiovascular disease remains the single most common cause of death in the UK and other Western countries. Primary prevention programmes, based on the reduction of modifiable risk factors such as cigarette smoking, hypercholesterolaemia and hypertension in an entire general population, have proved expensive and only partially successful at reducing incidence of disease, suggesting that supplementary approaches are required to reduce the burden of disease further. Current secondary prevention strategies have proved effective in reducing the rate of further cardiovascular events in individuals with symptomatic cardiovascular disease, but the vast majority of cardiovascular events occur in the ‘healthy’ population, with only 20% occurring in subjects with pre-existing clinical disease [1]. The major public health challenge is therefore to prevent new cases of clinical disease from developing in the apparently healthy but ‘at risk’ population. One approach is the identification of people with markers of asymptomatic atherosclerosis, who may be at increased risk of developing symptomatic cardiovascular disease, followed by targeted preventive measures.

Several markers have been suggested as potential predictors of cardiovascular morbidity and mortality, including non-invasive measures of sub-clinical atherosclerosis, such as carotid artery intima-media thickness, carotid plaques, aortic calcification and the ankle-brachial index (ABI) [2]. Of these, the ABI (the ratio of systolic blood pressure in the ankle to that in the arm), sometimes called the ankle-arm index or ankle-brachial pressure index, has perhaps shown the most promise as a potential tool in clinical practice and has been most widely investigated. Cross-sectional studies indicate that the ABI is a marker of generalised atherosclerosis and the test is currently used clinically in the assessment of peripheral arterial disease of the lower limbs, with a lower ratio associated with more severe disease. Given the well-recognised association between peripheral arterial disease and other forms of atherosclerotic disease, several studies have investigated the ABI and risk of subsequent cardiovascular morbidity and mortality in the general population. These studies are reviewed systematically here.

Section snippets

Identification of studies

The aim was to identify all relevant longitudinal studies that examined the ABI as a marker of subsequent cardiovascular events, available for review by July 2005. We included longitudinal studies (with over 1000 person years of follow-up) in which participants were representative of the general population (all ages, either sex) and which used any standard method for measurement and calculation of the ABI. Studies in which participants were selected according to presence of disease (such as

Results

We identified 680 citations, reviewed 50 full text articles, and identified 18 eligible papers according to our inclusion criteria (Fig. 1). Some major cardiovascular longitudinal studies in which ABI measurement was undertaken were excluded because subjects were categorised according to other peripheral arterial disease criteria (peripheral arterial bypass, amputation and/or abnormal flow velocities) in addition to ABI [3], [4]. Two of the identified studies were subsequently excluded as they

Discussion

In this systematic review of eleven, high quality, population-based cohort studies, we confirmed that a low ABI is associated with subsequent all cause mortality, cardiovascular mortality, coronary heart disease and stroke with a high degree of consistency. The main multivariate analysis showed significant associations in the presence of important co-variables, including a range of conventional cardiovascular risk factors and prevalent cardiovascular disease, indicating that the ABI may help to

Acknowledgements

JP and GF conceived the idea for the review. JP designed the study. CH and JP extracted and analysed the data and co-wrote the manuscript. GF and GM contributed to data analysis and commented on drafts. Members of the ABI collaboration had the opportunity to comment on a final draft of the paper. JP is guarantor. Photocopying/inter-library loans for some of the articles was paid for by the ABI Collaboration (supported by an educational grant from Sanofi Aventis).

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  • Cited by (0)

    1

    Members of the Ankle Brachial Index Collaboration: ARIC (W Chambless, AR Folsom, AT Hirsch); Belgian ABPI Study (M Dramaix); Cardiovascular Health Study (AB Newman, M Cushman); Edinburgh Artery Study (FGR Fowkes, AJ Lee, JF Price); Framingham Study (R d’Agostino, JM Murabito, C-Y Guo); Health in Men Study (P Norman, K Jamrozik); Hoorn Study (JM Dekker, LM Bouter, RJ Heine, G Nijpels, CDA Stehouwer); Honolulu Heart Program (JD Curb, KH Masaki, BL Rodriguez); InChianti Study (L Ferrucci, MM McDermott); Limburg Study (HE Stoffers, JD Hooi, JA Knottnerus); Men Born in 1914 Study (M Ogren, L Janzon, B Hedblad); Rotterdam Study (JC Witteman, MMB Breteler); San Diego Study (MH Criqui, RD Langer, A Fronek); San Luis Valley Diabetes Study (W Hiatt, R Hamman); Strong Heart Study (HE Resnick); Women's Health and Aging Study (J Guralnik, MM McDermott).

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