title: Vessel resistance to blood flow in the nailfold in patients with psoriasis: a prospective case-control echo Doppler-based study.
abstract: BACKGROUND
  Psoriasis is a disease in which endothelial cells seem to play an important pathogenic role. No report published to date has examined nail vascularity in patients with psoriasis.
  
  
  OBJECTIVE
  To evaluate the vascularity in the nails of patients with psoriasis treated with classic and biologic therapies for comparison with disease-free controls, and to evaluate whether there are differences in nail vascularity among patients with and without nail involvement.
  
  
  METHODS
  We performed a prospective study with two cohorts comprising 23 patients with moderate-to-severe psoriasis and 23 controls without psoriasis. We measured the nailfold vessel resistance index (NVRI) in each subgroup.
  
  
  RESULTS
  We found significant differences in the NVRI between patients and controls (P<0·001). Among patients with psoriasis, those with nail involvement showed a higher mean±SD NVRI (0·58±0·10) than those without (0·52±0·45).
  
  
  CONCLUSIONS
  Psoriasis decreases the blood flow in nails, suggesting that this skin disease confers an independent risk for microvascular changes. This outcome may be associated with greater risk of nail-related signs.
authors.affiliation: Departments of Dermatology Radiology, San Cecilio University Hospital, Granada 18012, Spain. huseinelahmed@hotmail.com
authors.forename: H
authors.initials: H
authors.lastname: Husein El-Ahmed
authors.forename: F
authors.initials: F
authors.lastname: Garrido-Pareja
authors.forename: J-C
authors.initials: JC
authors.lastname: Ruiz-Carrascosa
authors.forename: R
authors.initials: R
authors.lastname: Naranjo-Sintes
mesh_terms: D000328:Adult; D001783:Blood Flow Velocity / Q000502:physiology; D016022:Case-Control Studies; D005260:Female; D006801:Humans; D008297:Male; D008833:Microcirculation / Q000502:physiology; D055806:Microvessels / Q000503:physiopathology; D008875:Middle Aged; D009260:Nail Diseases / Q000503:physiopathology*; D009262:Nails / Q000098:blood supply*; D011446:Prospective Studies; D011565:Psoriasis / Q000503:physiopathology*; D018608:Ultrasonography, Doppler; D014655:Vascular Resistance / Q000502:physiology*; D055815:Young Adult