|Title||Impact of volunteer-related and methodology-related factors on the reproducibility of brachial artery flow-mediated vasodilation : Analysis of 672 individual repeated measurements|
|Author(s)||Mil, Anke C.C.M. van; Greyling, Arno; Zock, Peter L.; Geleijnse, Marianne; Hopman, Maria T.; Mensink, Ronald P.; Reesink, Koen D.; Green, Daniel J.; Ghiadoni, Lorenzo; Thijssen, Dick H.|
|Source||Journal of Hypertension 34 (2016)9. - ISSN 0263-6352 - p. 1738 - 1745.|
Chair Nutrition and Disease
Human Nutrition (HNE)
|Publication type||Refereed Article in a scientific journal|
|Keyword(s)||Doppler - endothelial function - flow-mediated dilation - reproducibility - ultrasonography|
Objectives: Brachial artery flow-mediated dilation (FMD) is a popular technique to examine endothelial function in humans. Identifying volunteer and methodological factors related to variation in FMD is important to improve measurement accuracy and applicability. Methods: Volunteer-related and methodology-related parameters were collected in 672 volunteers from eight affiliated centres worldwide who underwent repeated measures of FMD. All centres adopted contemporary expert-consensus guidelines for FMD assessment. After calculating the coefficient of variation (%) of the FMD for each individual, we constructed quartiles (n = 168 per quartile). Based on two regression models (volunteer-related factors and methodology-related factors), statistically significant components of these two models were added to a final regression model (calculated as β-coefficient and R 2). This allowed us to identify factors that independently contributed to the variation in FMD%. Results: Median coefficient of variation was 17.5%, with healthy volunteers demonstrating a coefficient of variation 9.3%. Regression models revealed age (β = 0.248, P <0.001), hypertension (β = 0.104, P <0.001), dyslipidemia (β = 0.331, P <0.001), time between measurements (β = 0.318, P <0.001), lab experience (β = -0.133, P <0.001) and baseline FMD% (β = 0.082, P <0.05) as contributors to the coefficient of variation. After including all significant factors in the final model, we found that time between measurements, hypertension, baseline FMD% and lab experience with FMD independently predicted brachial artery variability (total R2 = 0.202). Conclusion: Although FMD% showed good reproducibility, larger variation was observed in conditions with longer time between measurements, hypertension, less experience and lower baseline FMD%. Accounting for these factors may improve FMD% variability.