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Intra‐ and inter‐day reproducibility of low‐flow mediated constriction response in young adults
Author(s) -
Harbin Michelle M.,
Ostrem Joseph D.,
Evanoff Nicholas G.,
Kelly Aaron S.,
Dengel Donald R.
Publication year - 2018
Publication title -
clinical physiology and functional imaging
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.608
H-Index - 67
eISSN - 1475-097X
pISSN - 1475-0961
DOI - 10.1111/cpf.12448
Subject(s) - medicine , hyperaemia , brachial artery , intraclass correlation , reproducibility , reactive hyperemia , occlusion , constriction , vasodilation , cuff , coefficient of variation , vasoconstriction , cardiology , blood flow , nuclear medicine , surgery , blood pressure , clinical psychology , statistics , mathematics , psychometrics
Summary Purpose When assessing brachial endothelial function by reactive hyperaemia, stopping blood flow creates a period of low‐flow‐mediated constriction (L‐ FMC ). As little is known about how this parameter influences flow‐mediated vasodilation ( FMD ), the purpose of this study was to better understand this relationship and to determine the intra‐ and interday reproducibility of brachial L‐ FMC . Methods Brachial L‐ FMC and FMD were measured on 26 healthy, young adults (13 males, 13 females; 24·6 ± 2·7 years). Each participant had two assessments conducted on two separate visits, separated by a minimum of seven days. Brachial artery baseline diameter was imaged during rest. Continuous imaging of the artery was performed during the last 20 s of cuff‐occlusion to 180 s postcuff release. An L‐ FMC was considered present if the relative change from pre‐occlusion baseline to L‐ FMC artery diameter was less than −0·1%. Results Overall, there was a strong, positive correlation between increased brachial L‐ FMC and blunted FMD (visit 1 test 1: r = 0·758, P <0·001; visit 1 test 2: r = 0·706, P <0·001; visit 2 test 1: r = 0·836, P <0·001; visit 2 test 2: r = 0·857, P <0·001). The reproducibility of intra‐ and interday L‐ FMC diameter was intraclass correlation coefficients ( ICC ) = 0·627, coefficient of variation ( CV ) = 54·4% and ICC = 0·734, CV = 43·5%, respectively. Conclusion Vasoconstriction to low‐flow conditions influences the subsequent maximal dilation during reactive hyperaemia. However, L‐ FMC is variable as evidenced by the weak intra‐ and interday reproducibility of the measure. Further research should study brachial L‐ FMC reproducibility among varying populations and the implications L‐ FMC has on the interpretation of FMD results.