Heterogeneity in conduit artery function in humans: impact of arterial size

• Published in: American journal of physiology. Heart and circulatory physiology Vol. 295; no. 5; pp. H1927 - H1934
• Main Authors: Thijssen, Dick H. J, Dawson, Ellen A, Black, Mark A, Hopman, Maria T. E, Cable, N. Timothy, Green, Daniel J
• Format: Journal Article
• Language: English
• Published: United States American Physiological Society 01.11.2008
• Subjects: Adult; Arteries - anatomy & histology; Arteries - diagnostic imaging; Arteries - drug effects; Arteries - physiology; Blood pressure; Brachial Artery - anatomy & histology; Brachial Artery - physiology; Cardiology; Endothelium, Vascular - physiology; Femoral Artery - anatomy & histology; Femoral Artery - physiology; Humans; Male; Men; Nitrates; Nitroglycerin - pharmacology; Popliteal Artery - anatomy & histology; Popliteal Artery - physiology; Pulsatile Flow; Radial Artery - anatomy & histology; Radial Artery - physiology; Regional Blood Flow; Time Factors; Ultrasonic imaging; Ultrasonography, Doppler; Vasodilation - drug effects; Vasodilator Agents - pharmacology; Veins & arteries
• ISSN: 0363-6135; 1522-1539
• DOI: 10.1152/ajpheart.00405.2008

1 Research Institute for Sport and Exercise Science, Liverpool John Moore's University, Liverpool, United Kingdom; 2 Department of Physiology, Radboud University Nijmegen Medical Centre, Nijmegen, The Netherlands; and 3 School of Sport Science, Exercise and Health, The University of Western Australia, Crawley, Western Australia Submitted 17 April 2008 ; accepted in final form 2 September 2008 To determine whether conduit artery size affects functional responses, we compared the magnitude, time course, and eliciting shear rate stimulus for flow-mediated dilation (FMD) in healthy men ( n = 20; 31 ± 7 yr). Upper limb (brachial and radial) and lower limb (common and superficial femoral) FMD responses were simultaneously assessed, whereas popliteal responses were measured in the same subjects during a separate visit. Glyceryl trinitrate (GTN)-mediated responses were similarly examined. Edge detection and wall tracking of high-resolution B-mode arterial ultrasound images, combined with synchronized Doppler waveform envelope analysis, were used to calculate conduit artery diameter, blood flow, and shear rate continuously across the cardiac cycle. Baseline artery size correlated inversely with the FMD response ( r = –0.57, P < 0.001). Within-artery comparisons revealed a significant inverse correlation between artery size and FMD% for the radial ( r = –0.66, P = 0.001), brachial ( r = –0.55, P = 0.01), and popliteal artery ( r = –0.48, P = 0.03), but not for the superficial and common femoral artery. Normalization of FMD responses for differences in eliciting shear rate did not abolish the between-artery relationship for artery function and size ( r = –0.48, P < 0.001), suggesting that differences between artery function responses were not entirely due to size-related differences in shear rate. This was reinforced by a significant between-artery correlation for GTN responses and baseline artery size ( r = –0.74, P < 0.001). In summary, systematic differences exist in vascular function responses of conduit arteries that differ in size. This raises the possibility that differences in artery size within or between individuals may influence functional responses. flow-mediated dilation; nitroglycerine; arterial diameter; high-resolution ultrasound; Doppler Address for reprint requests and other correspondence: D. H. J. Thijssen, Research Institute for Sport and Exercise Science, Henry Cotton Campus, Liverpool John Moores Univ., 15-21 Webster St., Liverpool L3 2ET, United Kingdom (e-mail: d.thijssen{at}fysiol.umcn.nl )