ReviewRisk of mortality and cardiovascular disease associated with the ankle-brachial index: Systematic review
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).
References (28)
- et al.
Low ankle-brachial pressure index in 68-year-old men: prevalence, risk factors and prognosis. Results from prospective population study “Men born in 1914”, Malmo, Sweden
Eur J Vasc Surg
(1993) - et al.
Non-invasively detected carotid stenosis and ischaemic heart disease in men with leg arteriosclerosis
Lancet
(1993) - et al.
Ankle/brachial blood pressure in men >70 years of age and the risk of coronary heart disease
Am J Cardiol
(2000) - et al.
Ankle-brachial blood pressure in elderly men and the risk of stroke: the Honolulu Heart Program
J Clin Epidemiol
(2001) - et al.
Asymptomatic peripheral arterial occlusive disease predicted cardiovascular morbidity and mortality in a 7-year follow-up study
J Clin Epidemiol
(2004) Coronary heart disease epidemiology
(1992)- et al.
Prevention Conference V: beyond secondary prevention: identifying the high-risk patient for primary prevention: noninvasive tests of atherosclerotic burden: Writing Group III
Circulation
(2000) - et al.
Mortality over a period of 10 years in patients with peripheral arterial disease
N Engl J Med
(1992) - et al.
Microalbuminuria and peripheral arterial disease are independent predictors of cardiovascular and all-cause mortality, especially among hypertensive subjects: five-year follow-up of the Hoorn Study
Arterioscler Thromb Vasc Biol
(1999) - et al.
Is ankle/arm pressure predictive for cardiovascular mortality in older patients living in nursing homes?
Panminerva Med
(2003)
Incidence and predictors of coronary heart disease among older African Americans–the Cardiovascular Health Study
J Natl Med Assoc
Decreased ankle/arm blood pressure index and mortality in elderly women
JAMA
Ankle/arm pressure index in asymptomatic middle-aged males: an independent predictor of ten-year coronary heart disease mortality
Angiology
Ankle-arm index as a predictor of cardiovascular disease and mortality in the Cardiovascular Health Study
Arterioscler Thromb Vasc Biol
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).