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Flow-mediated dilation in human brachial artery after different circulatory occlusion conditions
journal contribution
posted on 2004-01-01, 00:00 authored by Andrew BetikAndrew Betik, V B Luckham, R L HughsonDifferent magnitudes and durations of postocclusion reactive hyperemia were achieved by occluding different volumes of tissue with and without ischemic exercise to test the hypotheses that flow-mediated dilation (FMD) of the brachial artery would depend on the increase in peak flow rate or shear stress and that the position of the occlusion cuff would affect the response. The brachial artery FMD response was observed by high-frequency ultrasound imaging with curve fitting to minimize the effects of random measurement error in eight healthy, young, nonsmoking men. Reactive hyperemia was graded by 5-min occlusion distal to the measurement site at the wrist and the forearm and proximal to the site in the upper arm. Flow was further increased by exercise during occlusion at the wrist and forearm positions. For the two wrist occlusion conditions, flow increased eightfold and FMD was only 1 to 2% (P > 0.05). After the forearm and upper arm occlusions, blood flow was almost identical but FMD after forearm occlusions was 3.4% (P < 0.05), whereas it was significantly greater (6.6%, P < 0.05) and more prolonged after proximal occlusion. Forearm occlusion plus exercise caused a greater and more prolonged increase in blood flow, yet FMD (7.0%) was qualitatively and quantitatively similar to that after proximal occlusion. Overall, the magnitude of FMD was significantly correlated with peak forearm blood flow (r = 0.59, P < 0.001), peak shear rate (r = 0.49, P < 0.002), and total 5-min reactive hyperemia (r = 0.52, P < 0.001). The prolonged FMD after upper arm occlusion suggests that the mechanism for FMD differs with occlusion cuff position.
History
Journal
American journal of physiology: heart and circulatory physiologyVolume
286Issue
1Pagination
H442 - H448Publisher
American Physiological SocietyLocation
Bethesda, Md.Publisher DOI
ISSN
0363-6135Language
engPublication classification
C1.1 Refereed article in a scholarly journalCopyright notice
2004, the American Physiological SocietyUsage metrics
Keywords
hyperemiaendotheliumshear stressischemic exerciseblood flowScience & TechnologyLife Sciences & BiomedicineCardiac & Cardiovascular SystemsPhysiologyPeripheral Vascular DiseaseCardiovascular System & CardiologyNITRIC-OXIDEBLOOD-FLOWENDOTHELIAL DYSFUNCTIONULTRASOUND ASSESSMENTREACTIVE HYPEREMIAHANDGRIP EXERCISEHUMAN FOREARMTIME-COURSEVASODILATIONDILATATIONPhysiology
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