High-throughput ambulatory assessment of digital reactive hyperemia: concurrent validity with known cardiovascular risk factors and potential confounding.

Abstract

Reactive hyperemia index (RHI) measurement through digital peripheral arterial tonometry (PAT) is proposed for cardiovascular disease (CVD) risk screening. We evaluated the concurrent validity of RHI, measured in a high-throughput ambulatory setting, with known CVD risk factors and biomarkers. PAT was included in the 2007 EADS/Augsburg (Germany) cohort follow-up. CVD risk factors (age, sex, hypertension, hyperlipidemia, diabetes, smoking, physical activity, prevalent coronary heart disease, family history, cholesterol, triglycerides, blood pressure (BP), waist-to-hip ratio (WHR)) and biomarkers (d-dimers, fibrinogen, log(c-reactive protein)) were assessed. The relationship between RHI and CVD risk factors and biomarkers was evaluated using multivariate linear regression, controlling for potential confounders (time of day, time since subject's last meal, baseline heart rate, examiner). Of 926 subjects approached, 710 underwent PAT and 603 (mean age 44.9+/-10 years, 88.7% men) with complete data were included for analysis. RHI was significantly related to being female (beta=0.128, p=0.02), low-density lipoprotein cholesterol (beta=-0.001, p=0.02), systolic BP (beta=0.007, p<0.001), WHR (beta=-1.04, p<0.01), time of day (beta=-0.011, p=0.04) and time since last meal (beta=0.013, p<0.01). Concurrent validity was partially demonstrated, while the need to control for potential confounding was reinforced. Participation was high and may be higher in less time-constrained settings.