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Updated: Mar 28, 2026
Ultrasound Assessment of Flow-Mediated Dilation of the Brachial and Superficial Femoral Arteries in Rats
Published on: November 3, 2016
Peak shear and peak flow mediated dilation: a time-course relationship
Nicholas G Evanoff1, Aaron S Kelly2,3, Julia Steinberger2
1Laboratory of Integrative Human Physiology, School of Kinesiology, University of Minnesota, Minneapolis, MN, 55455.
Insights
Children exhibit lower peak shear stress and flow-mediated dilation (FMD) responses compared to adults. However, the timing interval between peak shear stress and peak FMD remains consistent across age groups, suggesting age-related vascular dynamics.
Area of Science:
- Vascular physiology
- Pediatric cardiology
- Cardiovascular research
Background:
- Flow-mediated dilation (FMD) assesses endothelial function.
- Shear stress is a key stimulus for FMD.
- Understanding age-related differences in vascular response is crucial.
Purpose of the Study:
- To investigate the temporal relationship between brachial artery peak shear stress and FMD in children and adults.
- To compare shear stress and FMD dynamics across different age groups.
Main Methods:
- Sonographic imaging was used to track brachial artery diameter and shear stress.
- Reactive hyperemia was induced to measure FMD and shear stress.
- 122 children and 350 adults participated in the study.
Main Results:
- Children had significantly higher peak shear stress, shear area under the curve, and peak FMD compared to adults.
- The time to reach peak shear stress and peak FMD was shorter in children.
- The time interval between peak shear stress and peak FMD was similar in both children and adults.
Conclusions:
- Children demonstrate a reduced shear stress stimulus and FMD response relative to adults.
- Despite age-related differences in vascular dynamics, the temporal coupling between shear stress and FMD is preserved.
- This suggests potential alterations in smooth muscle cell responsiveness or other age-dependent vascular factors.
Purpose:
To explore the temporal relationship between brachial artery peak shear stress (Shear) and flow-mediated dilation (FMD) in children and adults.
Methods:
Shear and brachial artery diameter were tracked following reactive hyperemia in 122 children and 350 adults using sonographic imaging.
Results:
Peak Shear, Shear area under the curve (Shear(AUC)), and Peak FMD were significantly larger in children than in adults. The time to peak Shear (Shear(TTP)) and time to peak FMD (FMD(TTP)) were significantly lower in children, while there was no significant difference in time from Shear(TTP) to FMD(TTP) between children and adults.
Conclusions:
Children have a lower shear stimulus and FMD response than adults, but the time interval separating these events is similar. These differences could be due to changes in vascular dynamics with age, including reduced smooth muscle cell responsiveness and other factors. Despite differences in timing, the interval from peak Shear to peak FMD was similar in children and adults.
