Different methods of calculating ankle-brachial index in mid-elderly men and women: the Brazilian Longitudinal Study of Adult Health (ELSA-Brasil)

Abstract

The ankle-brachial index (ABI) is a marker of subclinical atherosclerosis related to health-adverse outcomes. ABI is inexpensive compared to other indexes, such as coronary calcium score and determination of carotid artery intima-media thickness (IMT). Our objective was to identify how the ABI can be applied to primary care. Three different methods of calculating the ABI were compared among 13,921 men and women aged 35 to 74 years who were free of cardiovascular diseases and enrolled in the Brazilian Longitudinal Study of Adult Health (ELSA-Brasil). The ABI ratio had the same denominator for the three categories created (the highest value for arm systolic blood pressure), and the numerator was based on the four readings for leg systolic blood pressure: the highest (ABI-HIGH), the mean (ABI-MEAN), and the lowest (ABI-LOW). The cut-off for analysis was ABI<1.0. All determinations of blood pressure were done with an oscillometric device. The prevalence of ABI<1% was 0.5, 0.9, and 2.7 for the categories HIGH, MEAN and LOW, respectively. All methods were associated with a high burden of cardiovascular risk factors. The association with IMT was stronger for ABI-HIGH than for the other categories. The proportion of participants with a 10-year Framingham Risk Score of coronary heart disease >20% without the inclusion of ABI<1.0 was 4.9%. For ABI-HIGH, ABI-MEAN and ABI-LOW, the increase in percentage points was 0.3, 0.7, and 2.3%, respectively, and the relative increment was 6.1, 14.3, and 46.9%. In conclusion, all methods were acceptable, but ABI-LOW was more suitable for prevention purposes.

Carotid intima-media thickness in the Brazilian Longitudinal Study of Adult Health (ELSA-Brasil): a narrative review

“…One of the greatest strengths of the ELSA-Brasil cohort is that it enables studies on the effects of social variables on clinical (bio- Miname et al 22 compared different protocols for calculating the ankle-brachial index (ABI, a measurement of peripheral artery disease) at the ELSA-Brasil baseline. ABI is based on the ratio of systolic BP measured at the ankle divided by systolic BP measured in the arm.…”

Associations of Cigarette Smoking With Subclinical Inflammation and Atherosclerosis: ELSA‐Brasil (The Brazilian Longitudinal Study of Adult Health)

“…We calculated the ABI by dividing the lowest of the 4 systolic blood pressure measurements of the leg by the highest systolic blood pressure measurements of the arm, as this method was shown to better estimate CVD risk for preventive purposes. 31 ABI ≤1 versus >1 was used to discriminate between normal and diseased peripheral arteries. ABI data were available for 14 038 participants in the final analytic sample.…”

The intrinsic prognostic value of the ankle–brachial index is independent from its mode of calculation

“…Its use and measurement methods were further detailed previously. 8 Several studies [14][15][16][17] compared the various methods of calculation of ABI in terms of their effect on the determination of PAD prevalence. Indeed, in the Multi-Ethnic Study of Atherosclerosis (MESA), 17 including subjects free from clinically apparent cardiovascular disease, the prevalence of PAD reported according to the method of ABI calculation varied from 3.7% to 14.6% in females and from 3.4% to 16% in males.…”