title: Rapid and extensive arterial adaptations after spinal cord injury.
abstract: OBJECTIVE
  To assess the time course of adaptations in leg vascular dimension and function within the first 6 weeks after a spinal cord injury (SCI).
  
  
  METHODS
  Longitudinal study design.
  
  
  METHODS
  University medical center and rehabilitation clinic.
  
  
  METHODS
  Six men were studied serially at 1, 2, 3, 4, and 6 weeks after SCI.
  
  
  METHODS
  Not applicable.
  
  
  METHODS
  Diameter, blood flow, and shear rate levels of the common femoral artery (CFA), superficial femoral artery (SFA), brachial artery, and carotid artery were measured with echo Doppler ultrasound (diameter, blood flow, shear rate). Endothelial function in the SFA was measured with flow-mediated dilation (FMD). In addition, leg volume and blood pressure measurements were performed.
  
  
  RESULTS
  Femoral artery diameter (CFA, 25%; SFA, 16%; P<.01) and leg volume (22%, P<.01) decreased simultaneously, and these reductions were largely accomplished within 3 weeks postinjury. Significant increases were observed for basal shear rate levels (64% increase at week 3; 117% increase at week 6; P<.01), absolute FMD responses (8% increase at week 3, 23% increase at week 6; P<.05) and relative FMD responses (26% increase at week 3, 44% increase at week 6; P<.001).
  
  
  CONCLUSIONS
  Our findings show a rapid onset of adaptations in arterial dimension and function to extreme inactivity in humans. Vascular adaptations include extensive reductions in femoral diameter and leg volume, as well as increased basal shear rate levels and FMD responses, which all appear to be largely accomplished within 3 weeks after an SCI.
authors.affiliation: Department of Physiology, Radboud University Nijmegen Medical Centre, Nijmegen, the Netherlands.
authors.forename: Patricia C
authors.initials: PC
authors.lastname: de Groot
authors.forename: Michiel W
authors.initials: MW
authors.lastname: Bleeker
authors.forename: Dirk H
authors.initials: DH
authors.lastname: van Kuppevelt
authors.forename: Luc H
authors.initials: LH
authors.lastname: van der Woude
authors.forename: Maria T
authors.initials: MT
authors.lastname: Hopman
mesh_terms: D000328:Adult; D000368:Aged; D001158:Arteries / Q000000981:diagnostic imaging / Q000473:pathology* / Q000503:physiopathology*; D001783:Blood Flow Velocity / Q000502:physiology; D001810:Blood Volume / Q000502:physiology; D004730:Endothelium, Vascular / Q000503:physiopathology*; D006801:Humans; D007866:Leg / Q000473:pathology; D008137:Longitudinal Studies; D008297:Male; D013119:Spinal Cord Injuries / Q000000981:diagnostic imaging / Q000473:pathology* / Q000503:physiopathology*; D013997:Time Factors; D014463:Ultrasonography; D014655:Vascular Resistance / Q000502:physiology; D014664:Vasodilation / Q000502:physiology*