title: Impaired vascular endothelial function in patients with restless legs syndrome: a new aspect of the vascular pathophysiology.
abstract: BACKGROUND
  Restless legs syndrome (RLS) is a common sleep disorder in which patients feel unpleasant leg sensations and the urge to move their legs during rest, particularly at night. Leg movement improves these symptoms. Although several studies have demonstrated an association between cardiovascular disease and RLS, the mechanisms underlying this relationship remain unclear. Recent studies have shown changes in the peripheral microvasculature, including altered blood flow and capillary tortuosity, and peripheral hypoxia. Vascular endothelial dysfunction can be assessed noninvasively with ultrasound measurements of brachial artery flow-mediated dilatation (FMD). Therefore, this study investigated FMD in RLS patients to determine the involvement of microvascular alterations in this disorder.
  
  
  METHODS
  The study enrolled 25 drug-naïve RLS patients and 25 sex- and age-matched controls and compared the FMD values of the two groups. RLS was diagnosed according to the criteria of the International Restless Legs Syndrome Study Group.
  
  
  RESULTS
  FMD was significantly lower in the RLS patients (6.6 ± 1.2%) compared to the controls (8.4 ± 1.8%; p<0.05) and the RLS patients showed a weak, negative correlation between RLS severity and FMD (r=-0.419, p=0.04). Multivariate linear regression analysis revealed that RLS (B=-1.87, 95% confidence interval [CI] -2.72 to -1.02; p<0.001) and age (B=-0.06; 95% CI -0.12 to -0.02; p<0.001) were significantly and inversely correlated with FMD.
  
  
  CONCLUSIONS
  This study demonstrated that RLS patients have poorer vascular endothelial function than normal healthy subjects and provides further evidence supporting the involvement of peripheral systems in the generation of RLS.
authors.affiliation: Department of Neurology, Ajou University School of Medicine, Suwon, South Korea.
authors.forename: Seung Yon
authors.initials: SY
authors.lastname: Koh
authors.affiliation: Department of Neurology, Ajou University School of Medicine, Suwon, South Korea.
authors.forename: Min Seung
authors.initials: MS
authors.lastname: Kim
authors.affiliation: Department of Neurology, Ajou University School of Medicine, Suwon, South Korea.
authors.forename: Sun Min
authors.initials: SM
authors.lastname: Lee
authors.affiliation: Department of Neurology, Ajou University School of Medicine, Suwon, South Korea.
authors.forename: Ji Man
authors.initials: JM
authors.lastname: Hong
authors.affiliation: Department of Neurology, Ajou University School of Medicine, Suwon, South Korea. Electronic address: jhyoon@gmail.com.
authors.forename: Jung Han
authors.initials: JH
authors.lastname: Yoon
mesh_terms: D000328:Adult; D000368:Aged; D001916:Brachial Artery / Q000503:physiopathology*; D005260:Female; D006801:Humans; D006979:Hyperthermia, Induced / Q000379:methods; D008297:Male; D008875:Middle Aged; D012148:Restless Legs Syndrome / Q000150:complications*; D012189:Retrospective Studies; D018709:Statistics, Nonparametric; D013349:Subclavian Steal Syndrome / Q000209:etiology*; D014463:Ultrasonography
keywords: Cardiovascular disease; Flow-mediated dilation; Restless legs syndrome; Vascular endothelial function; Willis–Ekbom disease