Temporal Responses of the Brachial Artery Following Forearm Occlusion

Abstract

0436 Measurement of flow-mediated dilation of the brachial artery in response to a sudden change in blood flow has emerged as a useful tool for atherosclerosis research. In the setting of cardiovascular disease risk factors flow-mediated dilation declines, perhaps suggesting a loss of normal endothelial function. Interestingly, little attention has been given to the temporal responses of the vessel's behavior following the occlusion period. PURPOSE: To examine the temporal response of the brachial artery following forearm occlusion. METHODS: Twelve healthy males (28 ± 5.47y) underwent highresolution ultrasonography of the brachial artery before and after 5 minutes of forearm occlusion. RESULTS: As show in the figure the average brachial artery diameter at rest was 3.52 ± 0.46mm. A significant decrease in brachial artery diameter was observed approx. 10 ± 4 sec after release of the occlusion (3.45 ± 0.47mm vs. baseline, p = 0.03), which was followed by a rapid increase in the diameter reaching a peak at approx. 49 ± 16sec (3.81 ± 0.48mm vs. baseline, p = 0.001). CONCLUSION: These results indicate a biphasic temporal pattern following 5 minutes of forearm occlusion. The mechanism for the initial decrease in diameter is uncertain, but may be a response to a change in fluid mechanics following cuff release or a myogenic influence. The subsequent increase in brachial diameter may in part be a reflection of endothelial mediated mechanisms. The temporal pattern may provide additional information regarding the structural and physiological status of the artery.Figure