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Choroidal blood flow response to hyperoxia and hypercapnia in patients with obstructive sleep apnea syndrome
Author(s) -
KHAYI H,
TONINI M,
PEPIN JL,
RENARD E,
BAGUET JP,
ROMANET JP,
GEISER MH,
CHIQUET C
Publication year - 2009
Publication title -
acta ophthalmologica
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.534
H-Index - 87
eISSN - 1755-3768
pISSN - 1755-375X
DOI - 10.1111/j.1755-3768.2009.266.x
Subject(s) - medicine , hypercapnia , obstructive sleep apnea , hyperoxia , polysomnography , blood flow , anesthesia , vasoconstriction , cardiology , apnea , lung , acidosis
Purpose Obstructive sleep apnea syndrome (OSA) is associated with ischemic and glaucomatous optic neuropathy. The physiopathology of these diseases includes an abnormal regulation in the optic nerve head vasculature. The aim of our study was to characterize the choroidal vascular reactivity to hyperoxia and 8% CO2 breathing in OSA patients, as compared with matched healthy control subjects. Methods Eighteen newly diagnosed OSA patients were included in this prospective study. Control subjects were matched with OSA patients for body mass index (BMI), gender and age. At the screening visit, each subject underwent a general exam, cardiovascular, neurologic and ophthalmological examinations, and underwent complete overnight polysomnography. The LDF instrument used in this study to measure subfoveal choroidal blood flow (ChBF) measured the following parameters: ChBVel (kHz); volume, ChBVol (in arbitrary units, AU) and the relative flow, ChBF = ChBVel ? ChBVol (in AU). Vascular choroidal reactivity was tested during hyperoxia and hypercapnia (8% CO2) inhalation. Results OSA patients exhibited a similar choroidal reactivity during hyperoxia (stability of choroidal blood flow) and hypercapnia (1.5% increase in choroidal blood flow per 1 mmHg PtCO2) than controls. Conclusion This prospective comparative study explored for the first time the choroidal blood flow of OSA patients and results showed that subfoveal ChBF reactivity to gas in OSA patients is similar to healthy control subjects. These preliminary results suggest that choroidal vasculature is protected against the inbalance between the vasodilation (NO) and vasoconstriction (endothelin) system.