title: Correlation of carotid artery reactivity with cardiovascular risk factors and coronary artery vasodilator responses in asymptomatic, healthy volunteers.
abstract: Carotid artery reactivity (CAR%), involving carotid artery diameter responses to a cold pressor test (CPT), is a noninvasive measure of conduit artery function in humans. This study examined the impact of age and cardiovascular risk factors on the CAR% and the relationship between CAR% and coronary artery vasodilator responses to the CPT.
  
  
  
  Ultrasound was used to measure resting and peak carotid artery diameters during the CPT, with CAR% being calculated as the relative change from baseline (%). We compared CAR% between young (n = 50, 24 ± 3 years) and older participants (n = 44, 61 ± 8 years), and subsequently assessed relationships between CAR% and traditional cardiovascular risk factors in 50 participants (44 ± 21 years). Subsequently, we compared left anterior descending (LAD) artery velocity (using transthoracic Doppler) with carotid artery diameter (i.e. CAR%) during the CPT (n = 33, 37 ± 17 years).
  
  
  
  A significantly larger CAR% was found in young versus older healthy participants (4.1 ± 3.7 versus 1.8 ± 2.6, P < 0.001). Participants without cardiovascular risk factors demonstrated a higher CAR% than those with at least two risk factors (2.9 ± 2.9 versus 0.5 ± 2.9, P = 0.019). Carotid artery diameter and LAD velocity increased during CPT (P < 0.001). Carotid diameter and change in velocity correlated with LAD velocity (r = 0.486 and 0.402, P < 0.004 and 0.02, respectively).
  
  
  
  Older age and cardiovascular risk factors are related to lower CAR%, while CAR% shows good correlation with coronary artery responses to the CPT. Therefore, CAR% may represent a valuable technique to assess cardiovascular risk, while CAR% seems to reflect coronary artery vasodilator function.
authors.affiliation: aRadboud Institute for Health Sciences, Department of Physiology, Radboud University Medical Center, Nijmegen, The Netherlands bResearch institute for Sport and Exercise Sciences, Liverpool John Moores University, Liverpool, UK cDivision of Human Nutrition, Wageningen University, Wageningen, The Netherlands dSchool of Sports Science, Exercise and Health, The University of Western Australia, Crawley, Western Australia, Australia.
authors.forename: Anke C C M
authors.initials: AC
authors.lastname: van Mil
authors.forename: Yvonne
authors.initials: Y
authors.lastname: Hartman
authors.forename: Frederieke
authors.initials: F
authors.lastname: van Oorschot
authors.forename: Annemieke
authors.initials: A
authors.lastname: Heemels
authors.forename: Nikki
authors.initials: N
authors.lastname: Bax
authors.forename: Ellen A
authors.initials: EA
authors.lastname: Dawson
authors.forename: Nicola
authors.initials: N
authors.lastname: Hopkins
authors.forename: Maria T E
authors.initials: MT
authors.lastname: Hopman
authors.forename: Daniel J
authors.initials: DJ
authors.lastname: Green
authors.forename: David L
authors.initials: DL
authors.lastname: Oxborough
authors.forename: Dick H J
authors.initials: DH
authors.lastname: Thijssen
mesh_terms: D000328:Adult; D000367:Age Factors; D000368:Aged; D000369:Aged, 80 and over; D001783:Blood Flow Velocity; D002318:Cardiovascular Diseases / Q000503:physiopathology; D002339:Carotid Arteries / Q000000981:diagnostic imaging / Q000502:physiology*; D059168:Carotid Intima-Media Thickness; D003080:Cold Temperature; D003331:Coronary Vessels / Q000502:physiology*; D005260:Female; D064368:Healthy Volunteers; D006801:Humans; D008297:Male; D008875:Middle Aged; D012307:Risk Factors; D014664:Vasodilation; D055815:Young Adult