title: Low level laser therapy in primary Raynaud's phenomenon--results of a placebo controlled, double blind intervention study.
abstract: OBJECTIVE
  To assess the efficacy of low level laser therapy in patients with primary Raynaud's phenomenon and predict the success of laser therapy by clinical characteristics.
  
  
  METHODS
  Forty-eight patients were included in a randomized placebo controlled, double blind crossover study. Laser and sham therapy each were applied 5 days a week for 3 weeks. Clinical symptoms, exposure to triggers, and frequency and intensity of attacks were recorded in diaries. Results of infrared thermography before onset and at the end of both irradiation sequences were evaluated. Primary endpoint was the average intensity of attacks; secondary endpoints were average number of attacks and thermography results. Age, sex, duration of symptoms, age at onset of symptoms, evoking conditions other than cold, maximum temperature drop after cold provocation, and rewarming time after cold provocation were tested as potential predictors.
  
  
  RESULTS
  Number of attacks and their intensity were significantly reduced during laser therapy compared to sham treatment. Thermographic parameters did not reach statistical significance. In a stepwise multiple regression analysis, evoking conditions other than cold (stress, wetness as additional triggers), rewarming time, and temperature decrease after cold provocation were significant predictors of therapeutic efficacy.
  
  
  CONCLUSIONS
  Low level laser therapy reduces frequency and severity of Raynaud attacks. The effect is most pronounced in patients with signs of decreased threshold for vasospasm and less effective in patients with delayed hyperemia.
authors.affiliation: Department of Angiology, Hanusch Hospital, Heinrich Collinstrasse 30, A-1140 Vienna, Austria. Mirko.Hirsch@wgkk.sozvers.at
authors.forename: Mirko
authors.initials: M
authors.lastname: Hirschl
authors.forename: Reinhold
authors.initials: R
authors.lastname: Katzenschlager
authors.forename: Claudia
authors.initials: C
authors.lastname: Francesconi
authors.forename: Michael
authors.initials: M
authors.lastname: Kundi
mesh_terms: D000704:Analysis of Variance; D018592:Cross-Over Studies; D004311:Double-Blind Method; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D016014:Linear Models; D028022:Low-Level Light Therapy / Q000379:methods*; D008297:Male; D010147:Pain Measurement; D011336:Probability; D011928:Raynaud Disease / Q000175:diagnosis* / Q000532:radiotherapy*; D012016:Reference Values; D018570:Risk Assessment; D012720:Severity of Illness Index; D016896:Treatment Outcome