title: Low-flow mediated constriction is endothelium-dependent: effects of exercise training after radial artery catheterization.
abstract: BACKGROUND
  Radial artery catheterization is associated with endothelial denudation and impaired vasodilator function, while postcatheterization exercise training may enhance artery function. The impact of catheterization and subsequent exercise training on low-flow mediated vasoconstriction (L-FMC) has not previously been studied. The aim of this study was to examine whether radial artery L-FMC is impaired by catheterization and consequent endothelial denudation. A further aim was to examine the effect of local handgrip exercise training on radial artery L-FMC and flow-mediated dilation (FMD) after transradial catheterization.
  
  
  RESULTS
  Thirty-two subjects undergoing transradial catheterization underwent assessment of L-FMC and FMD in the catheterized and contralateral radial artery before, and the day after, catheterization. A further 18 patients were recruited and randomly assigned to either a 6-week handgrip exercise training program (N=9) or a nonexercise control period (N=9). L-FMC was attenuated 1 day postcatheterization in the catheterized arm (-2.07±0.84 to 0.35±0.83), but unchanged in the noncatheterized arm (-0.93±0.86 to -0.90±0.92; P<0.05). In the training study, both FMD and L-FMC of the catheterized arm were preserved in the exercise group 7 weeks after catheterization (FMD-pre, 6.84±0.79; FMD-post, 6.85±1.16; L-FMC-pre, -2.14±1.42; L-FMC-post, -3.58±1.04%), but reduced in the control group (FMD-pre, 8.27±1.52; FMD-post, 4.66±0.70; P=0.06; L-FMC-pre, -3.26±1.19; L-FMC-post, -1.34±1.27%; P<0.05).
  
  
  CONCLUSIONS
  Catheterization, and associated endothelial denudation, decreases L-FMC in the radial artery, suggesting that it is endothelium-dependent. Moreover, we demonstrate for the first time that exercise training has beneficial impacts on radial artery vasodilator and constrictor function.
authors.affiliation: Research Institute for Sport and Exercise Sciences, Liverpool John Moores University, Liverpool, United Kingdom. e.dawson@ljmu.ac.uk
authors.forename: Ellen A
authors.initials: EA
authors.lastname: Dawson
authors.forename: Amr
authors.initials: A
authors.lastname: Alkarmi
authors.forename: Dick H J
authors.initials: DH
authors.lastname: Thijssen
authors.forename: Sudhir
authors.initials: S
authors.lastname: Rathore
authors.forename: Diane E
authors.initials: DE
authors.lastname: Marsman
authors.forename: N Timothy
authors.initials: NT
authors.lastname: Cable
authors.forename: D Jay
authors.initials: DJ
authors.lastname: Wright
authors.forename: Daniel J
authors.initials: DJ
authors.lastname: Green
mesh_terms: D000368:Aged; D001783:Blood Flow Velocity; D002406:Catheterization, Peripheral / Q000009:adverse effects*; D004730:Endothelium, Vascular / Q000293:injuries / Q000503:physiopathology*; D004739:England; D005081:Exercise Therapy; D005260:Female; D018737:Hand Strength; D006801:Humans; D008297:Male; D008875:Middle Aged; D017534:Radial Artery / Q000293:injuries / Q000503:physiopathology*; D012039:Regional Blood Flow; D013997:Time Factors; D016896:Treatment Outcome; D057772:Vascular System Injuries / Q000209:etiology / Q000503:physiopathology / Q000628:therapy*; D014661:Vasoconstriction; D014664:Vasodilation