title: [Endothelium-dependent vasodilation in patients with obstructive sleep apnea-hypopnea syndrome].
abstract: OBJECTIVE
  To evaluate the endothelial function in patients with obstructive sleep apnea-hypopnea syndrome (OSAHS) by measuring the brachial artery diameter during reactive hyperemia.
  
  
  METHODS
  Thirty patients with OSAHS (8 with mild and 22 with moderate/severe OSAHS) and 10 control subjects were studied. Brachial artery diameter was measured with Doppler ultrasound under baseline conditions, during reactive hyperemia (an endothelium-dependent dilatation) and after sublingual administration of nitroglycerin (an endothelium-independent vasodilator). The dilative rate of brachial artery in different conditions was calculated to evaluate the endothelial function.
  
  
  RESULTS
  The dilative rate of brachial artery in the control group, the mild OSAHS group and the moderate/severe OSAHS group were (15.2 +/- 2.6)%, (14.3 +/- 3.2)% and (9.8 +/- 4.9)%, respectively. There was a significant decrease of endothelium-dependent flow-mediated dilation in the moderate/severe OSAHS group compared to the control group and the mild OSAHS group. No significant difference in endothelium-independent vasodilator after sublingual administration of nitroglycerin was found among the three groups.
  
  
  CONCLUSIONS
  Patients with moderate/severe OSAHS have impaired endothelium-dependent vasodilatation, and OSAHS itself maybe a risk factor for endothelial dysfunction.
authors.affiliation: Institute of Respiratory Diseases, First Hospital, China Medical University, Shenyang 110001, China.
authors.forename: Zan-feng
authors.initials: ZF
authors.lastname: Wang
authors.forename: Xue-wei
authors.initials: XW
authors.lastname: Feng
authors.forename: Jian
authors.initials: J
authors.lastname: Kang
mesh_terms: D000328:Adult; D001916:Brachial Artery / Q000000981:diagnostic imaging; D016022:Case-Control Studies; D004730:Endothelium, Vascular / Q000503:physiopathology*; D045462:Endothelium-Dependent Relaxing Factors; D006801:Humans; D008875:Middle Aged; D020181:Sleep Apnea, Obstructive / Q000000981:diagnostic imaging / Q000503:physiopathology*; D014463:Ultrasonography; D014664:Vasodilation
chemical_list: D045462:Endothelium-Dependent Relaxing Factors