Intra‐ and inter‐day reproducibility of low‐flow mediated constriction response in young adults

Abstract

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.

A larger low‐flow‐mediated constrictor response is associated with augmented flow‐mediated dilation in the popliteal artery

“…Endothelial function in upper‐limb arteries does not reflect endothelial function in the popliteal artery (O'Brien et al, 2019a; Thijssen et al, 2008). The interactions between upper‐limb L‐FMC and FMD responses are controversial (Gori et al, 2010, 2012, 2017; Harbin et al, 2017; Harrison et al, 2011; Irace et al, 2016; Spiro et al, 2011). However, the results of the present study are consistent with Spiro et al (2011) who observed a negative relationship between brachial artery L‐FMC and FMD in healthy adults, but extends these observations to the popliteal artery and establishes the independent association between these measures of endothelial vasomotor function.…”

“…Tracking the lumen diameter throughout the ischemic period is recommended by FMD guidelines (Thijssen et al, 2011a). Research in upper-limb arteries (ie brachial or radial) have reported conflicting findings, with a larger L-FMC response being associated with a smaller FMD (Harbin et al, 2017;Harrison et al, 2011;Irace et al, 2016), larger FMD (Gori et al, 2017;Spiro et al, 2011) or no relationship with FMD (Gori et al, 2010(Gori et al, , 2012Spiro et al, 2011). Although both FMD and L-FMC are mediated by changes in shear-stress, they involve different vascular smooth muscle signalling mechanisms, which may support a lack of relationship between them.…”

“…The purpose of the present study was to evaluate the association between popliteal relative L-FMC and FMD responses in healthy adults. Given the conflicting reports of this relationship in radial and brachial arteries (Gori et al, 2010(Gori et al, , 2012(Gori et al, , 2017Harbin et al, 2017;Harrison et al, 2011;Irace et al, 2016;Spiro et al, 2011), as well as the heterogeneous endothelial-dependent responses between upper-and lower-limb arteries highlighted above (O'Brien et al, 2019a;Thijssen et al, 2011b), the present study did not include a directional hypothesis.…”