Vascular endothelial dysfunction in patients with mild obstructive sleep apnea syndrome.
BACKGROUND
We investigated endothelial dysfunction, an early manifestation of atherosclerosis, in patients with mild obstructive sleep apnea syndrome (OSAS) (5/h < AHI < 15/h).


METHODS
Endothelium-dependent and -independent vasodilatory function was tested in 10 patients with mild OSAS, 12 healthy controls and 20 subjects with moderate to severe OSAS using the hand vein compliance technique.


RESULTS
Maximum endothelium-dependent vasodilation to bradykinin (Emax) was significantly blunted in patients with mild OSAS (68.6 +/- 30.2 %) compared to healthy controls (94.8 +/- 9.5 %; p < 0.05; moderate to severe OSAS: 57.1 +/- 23.4 %; p = 0.33). Mean endothelium-independent venodilation was not altered. After 160.7 +/- 82.2 nights of CPAP therapy, mean Emax was significantly improved to 90.8 +/- 23.8 % (p < 0.01 vs. baseline; p = 0.7 vs. healthy controls) in 7 patients with mild OSAS.


CONCLUSIONS
Systemic endothelium-dependent venodilation is markedly reduced in subjects with mild OSAS, which may imply adverse cardiovascular consequences. CPAP-treatment leads to a sustained restoration of endothelial dysfunction in these patients and is thus highly recommended.
Duchna
Hans-Werner
HW
University Hospital Bergmannsheil, Ruhr-University Bochum, Medical Clinic III, Pulmonary Medicine, Allergology, Sleep- and Ventilatory Medicine, Bochum, Germany. hans-werner.duchna@ruhr-uni-bochum.de
Stoohs
Riccardo
R
Guilleminault
Christian
C
Christine Anspach
Marie
M
Schultze-Werninghaus
Gerhard
G
Orth
Maritta
M
D000293:Adolescent; D000328:Adult; D000368:Aged; D050197:Atherosclerosis / Q000175:diagnosis* / Q000209:etiology; D015992:Body Mass Index; D001920:Bradykinin / Q000008:administration & dosage; D045422:Continuous Positive Airway Pressure; D003627:Data Interpretation, Statistical; D004305:Dose-Response Relationship, Drug; D004730:Endothelium, Vascular / Q000503:physiopathology*; D006801:Humans; D007262:Infusions, Intravenous; D008297:Male; D008875:Middle Aged; D005996:Nitroglycerin / Q000008:administration & dosage; D018579:Patient Selection; D017286:Polysomnography; D012044:Regression Analysis; D020181:Sleep Apnea, Obstructive / Q000150:complications / Q000175:diagnosis / Q000503:physiopathology* / Q000628:therapy; D014664:Vasodilation; D014665:Vasodilator Agents / Q000008:administration & dosage; D014680:Veins / Q000503:physiopathology
D014665:Vasodilator Agents; D005996:Nitroglycerin; D001920:Bradykinin