title: Overnight variability in transcutaneous carbon dioxide predicts vascular impairment in women.
abstract: While there are a number of studies demonstrating association between arterial oxyhaemoglobin saturation events during sleep and markers of vascular impairment, the contribution of peripheral carbon dioxide to the development of atherosclerosis is poorly understood. We used ultrasound imaging to measure carotid artery intima-media thickness (IMT), as well as flow-mediated dilatation (FMD) and nitroglycerin-mediated dilatation (NMD) of brachial artery, in 103 generally healthy 46-year-old (+/-2 years) women. Characteristic event patterns were extracted from their overnight recordings of arterial oxyhaemoglobin saturation , end-tidal partial pressure of carbon dioxide and transcutaneous partial pressure of carbon dioxide . Importance of the event patterns was evaluated through predictive modelling of classes of the ultrasound measurements while controlling for potential confounders. Prediction accuracy was assessed with cross-validation and reported as the area under the receiver operating characteristic curve (AUC). Overnight patterns predicted each of the ultrasound measurements with high accuracy (IMT, AUC = 0.70; FMD, AUC = 0.75; and NMD, AUC = 0.81; all with P < 0.001). Adding the or patterns into the models did not significantly increase their predictive powers (AUC = 0.72, AUC = 0.77 and AUC = 0.83, respectively). The most important patterns reflected overnight variability in . These results suggest a novel link between overnight carbon dioxide events and early signs of vascular impairment in middle-aged women. Non-invasive measurements combined with non-linear modelling techniques could be used to reveal potential markers of vascular impairment present in relatively healthy subjects.
authors.affiliation: Sleep Research Unit, University of Turku, Dentalia, Lemminkäisenkatu 2, FI-20520 Turku, Finland. jemato@utu.fi
authors.forename: Jenni
authors.initials: J
authors.lastname: Aittokallio
authors.forename: Olli
authors.initials: O
authors.lastname: Polo
authors.forename: Jukka
authors.initials: J
authors.lastname: Hiissa
authors.forename: Arho
authors.initials: A
authors.lastname: Virkki
authors.forename: Jyri
authors.initials: J
authors.lastname: Toikka
authors.forename: Olli
authors.initials: O
authors.lastname: Raitakari
authors.forename: Tarja
authors.initials: T
authors.lastname: Saaresranta
authors.forename: Tero
authors.initials: T
authors.lastname: Aittokallio
mesh_terms: D000328:Adult; D050197:Atherosclerosis / Q000097:blood* / Q000175:diagnosis*; D015415:Biomarkers / Q000097:blood; D001785:Blood Gas Monitoring, Transcutaneous; D002245:Carbon Dioxide / Q000097:blood*; D002339:Carotid Arteries / Q000000981:diagnostic imaging; D005260:Female; D006801:Humans; D008137:Longitudinal Studies; D008875:Middle Aged; D008954:Models, Biological; D005996:Nitroglycerin / Q000494:pharmacology; D017286:Polysomnography / Q000379:methods*; D011237:Predictive Value of Tests; D012044:Regression Analysis; D017539:Tunica Intima / Q000000981:diagnostic imaging; D017540:Tunica Media / Q000000981:diagnostic imaging; D014463:Ultrasonography; D014664:Vasodilation / Q000187:drug effects; D014665:Vasodilator Agents / Q000494:pharmacology
chemical_list: D015415:Biomarkers; D014665:Vasodilator Agents; D002245:Carbon Dioxide; D005996:Nitroglycerin