title: Double pass 595 nm pulsed dye laser at a 6 minute interval for the treatment of port-wine stains is not more effective than single pass.
abstract: BACKGROUND
  Pulsed dye laser (PDL) is the first choice for treatment of port wine stains (PWS). However, outcome is highly variable and only a few patients achieve complete clearance. The objective of the study was to compare efficacy and safety of single pass PDL with double pass PDL at a 6 minute interval.
  
  
  METHODS
  We conducted a randomized within-patient controlled study on PWS resistant to multiple single pass PDL treatments. In each patient two similar PWS areas were randomly allocated to PDL treatment (595 nm, 7 mm spot size, 1.5 mseconds pulse duration) using, as a control treatment, a single pass (12 J/cm(2)) or, as a new treatment, a double pass PDL (11 J/cm(2), second pass 6 minutes after the first pass). Both test areas were treated two times, 8 weeks apart. PWS clearance was assessed by two blinded dermatologists, and by color measurement (L*a*b) using reflectance spectroscopy, at 3 months follow-up.
  
  
  RESULTS
  Sixteen out of 17 included patients completed follow-up. The mean number of treatments before inclusion was 15. Overall color assessed by spectrophotometer showed no improvement for either single or double pass PDL. Blinded Physician Global Assessment and Patient Global Assessment showed a high variability in outcome, with mostly only moderate improvement of the PWS for either single pass or double pass PDL. Furthermore, there was no significant difference in any of the outcomes between single pass and double pass PDL.
  
  
  CONCLUSIONS
  At the chosen settings and after two treatment sessions, double pass PDL at a 6 minute interval does not result in improved clearance of PWS as compared to single pass treatment.
authors.affiliation: Department of Dermatology, Flevoziekenhuis, Almere, The Netherlands.
authors.forename: M A D
authors.initials: MA
authors.lastname: Peters
authors.forename: A M
authors.initials: AM
authors.lastname: van Drooge
authors.forename: A
authors.initials: A
authors.lastname: Wolkerstorfer
authors.forename: M J C
authors.initials: MJ
authors.lastname: van Gemert
authors.forename: J P W
authors.initials: JP
authors.lastname: van der Veen
authors.forename: J D
authors.initials: JD
authors.lastname: Bos
authors.forename: J F
authors.initials: JF
authors.lastname: Beek
mesh_terms: D000328:Adult; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D017496:Hypopigmentation / Q000209:etiology; D054025:Lasers, Dye / Q000009:adverse effects / Q000627:therapeutic use*; D008297:Male; D008875:Middle Aged; D019339:Port-Wine Stain / Q000601:surgery*; D013997:Time Factors; D016896:Treatment Outcome; D055815:Young Adult