Abstract P008: Abnormal Ankle-Brachial Index is Inversely Associated with Improved Cardiovascular Health

Abstract

Background/Objective: An abnormal ankle-brachial index (ABI) strongly correlates with higher mortality in patients with cardiovascular disease however, the inverse link has not been established for cardiovascular (CV) health. The American Heart Association (AHA) aims to improve CV health by 20% by 2020 and has thus proposed the use of CV health metrics (Life’s Simple 7 or LS7). This study examines the relationship of abnormally low ABI with CV health. Methods: We evaluated 5,308 men and women aged ≥40 years, without history of CVD or diabetes mellitus (DM), participating in NHANES from 1999-2004. Abnormally low ABI was defined as ABI< 1.00 which included borderline low [0.91-0.99] and low ABI [<=0.90]). LS7 was scored on a 0-14 point scale and calculated based on poor, intermediate and ideal categories of 7 health components: diet, BMI, smoking, physical activity, blood pressure, glucose and cholesterol. LS7 scores were categorized as inadequate (0-7points), average (8-11) and optimum (12-14) CV health. Ordinal logistic regression models identified associations between abnormal ABI and CV health, with adjustments for sex, age, race/ethnicity, socioeconomic status and hs-CRP. Results: The mean (95% CI) LS7 score was 7.4 (7.3-7.5), with the majority of the population (75.3%) clustered at the lower end of average CV health. Adjusted models demonstrated that, compared to those with inadequate CV health, those with average CV health experienced 28% lower odds of abnormal ABI (OR 0.72, 95% CI; 0.52-0.97). Further improving CV health from inadequate to optimum was associated with 78% lower odds of abnormal ABI (OR 0.22, 95% CI; 0.09-0.57). On examining individual components, only blood pressure was found to be significantly associated with lower odds of abnormal ABI. Those with intermediate, as compared to poor, blood pressure readings showed 32% lower odds of abnormal ABI (OR 0.68, 95% CI; 0.48-0.94) while those with ideal blood pressure showed a 61% lower odds of abnormal ABI (OR 0.39, 95% CI; 0.21-0.72). Discussion/Conclusion: Although those with average CV health experienced lower odds of abnormal ABI, improving CV health to optimum can significantly lower these odds. This suggests that optimizing cardiovascular health, particularly in those who have not yet been affected by CVD or DM, can significantly slow or prevent progression of systemic atherosclerosis.