title: Nailfold capillaroscopy and laser Doppler fluxmetry for evaluation of Raynaud's phenomenon: how valid is the local cooling test?
abstract: BACKGROUND
  Since there is a need for an objective parameter of microcirculation in follow-up of patients with Raynaud's syndrome we evaluated the reproducibility of the reaction to a cold exposure test with nailfold capillaroscopy and laser Doppler fluxmetry during a winter period.
  
  
  METHODS
  10 healthy subjects and 16 patients with primary Raynaud's syndrome were evaluated with nailfold capillaroscopy and laser Doppler fluxmetry of the finger tips during and after a standardized cold exposure stress test. The measurements were repeated in the controls within 2 weeks, in the patient population twice within 24 weeks.
  
  
  RESULTS
  In the healthy controls the percentage of capillaries with flow stop was stable (r = 0.785) and the duration of flow stop was reproducible (r = 0.993). Both parameters were significantly lower in controls than in the patients. The flow stop durations in patients varied intra-individually to a great extent between the different weeks without any significant correlation. For all calculated laser Doppler perfusion and time parameters we did not find any significant differences between controls and patients nor any consistent correlations in the intra-individual comparison within the different weeks for both, controls and patients.
  
  
  CONCLUSIONS
  Nailfold capillaroscopy during cold exposure is able to discriminate between healthy persons and patients with primary Raynaud's syndrome, but seems to be of minor value for follow-up evaluation of patients because of intraindividual variations. Laser Doppler fluxmetry is invalid for both purposes when using the applied cold exposure test.
authors.affiliation: Department of Angiology, Hannover Medical School.
authors.forename: A
authors.initials: A
authors.lastname: Creutzig
authors.forename: S
authors.initials: S
authors.lastname: Hiller
authors.forename: R
authors.initials: R
authors.lastname: Appiah
authors.forename: J
authors.initials: J
authors.lastname: Thum
authors.forename: L
authors.initials: L
authors.lastname: Caspary
mesh_terms: D000328:Adult; D002196:Capillaries / Q000473:pathology / Q000503:physiopathology; D003080:Cold Temperature; D005260:Female; D006801:Humans; D017078:Laser-Doppler Flowmetry; D008297:Male; D008833:Microcirculation / Q000503:physiopathology; D018715:Microscopy, Video; D008875:Middle Aged; D009262:Nails / Q000098:blood supply*; D011928:Raynaud Disease / Q000175:diagnosis* / Q000503:physiopathology; D012016:Reference Values