Clinical Research
Peripheral Artery Disease
Alternative Ankle-Brachial Index Method Identifies Additional At-Risk Individuals

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Objectives

The aim of this study was to determine whether use of an alternative ankle-brachial index (ABI) calculation method improves mortality risk prediction compared with traditional methods.

Background

The ABI is used to diagnose peripheral arterial disease (PAD) and to identify those at risk for cardiovascular events. Traditionally, the ABI is calculated with the higher of the dorsalis pedis and posterior tibial ankle arteries. Studies directly comparing calculation methods are limited.

Methods

The ABI was calculated at baseline in 1,413 study participants undergoing nonemergent coronary angiography subsequently followed for all-cause and cardiovascular mortality. There were 224 individuals assigned to the traditional-PAD group (ABI <0.90) with the traditional ABI method. Of those remaining, an alternative ABI method using the lower of the 2 ankle pressures assigned 282 patients to the alternative-PAD group. The 862 individuals not assigned to PAD by either method were the no-PAD group.

Results

There were 163 mortalities during a median follow-up of 5.0 years. Adjusted Cox regression models showed that the alternative-PAD group had an increased risk for all-cause (hazard ratio [HR]: 1.49; 95% confidence interval: 1.01 to 2.19) and cardiovascular mortality (HR: 3.21; 95% confidence interval: 1.53 to 6.37) versus the no-PAD group. Additionally, in the no-PAD group, there was an 11% (HR: 1.11; 95% confidence interval: 1.05 to 1.17) increased risk of all-cause mortality/1-mm Hg increased difference between the left and right brachial systolic pressures.

Conclusions

The implementation of an alternative ABI method and use of the brachial difference identifies individuals at an increased risk for mortality who are currently missed with traditional ABI methods. Current ABI protocols might need to be evaluated.

Key Words

diagnosis
mortality
peripheral artery disease

Abbreviations and Acronyms

ABI
ankle-brachial index
BMI
body mass index
CAD
coronary artery disease
HDL
high-density lipoprotein
HR
hazard ratio
MACE
major adverse cardiovascular event(s)

Cited by (0)

This work was funded by grants from the National Institutes of Health (K12HL087746 to Dr. Cooke) and the American Heart Association (10BGIA3290011 to Dr. Leeper). The authors have reported that they have no relationships relevant to the contents of this paper to disclose.