title: Brachial artery diameter, blood flow and flow-mediated dilation in sleep-disordered breathing.
abstract: Clinic-based, case-control studies linked sleep-disordered breathing (SDB) to markers of endothelial dysfunction. We attempted to validate this association in a large community-based sample, and evaluate the relation of SDB to arterial diameter and peripheral blood flow. This community-based, cross-sectional observational study included 327 men and 355 women, aged 42-83 years, from the Framingham Heart Study site of the Sleep Heart Health Study. The polysomnographically derived apnea-hypopnea index and the hypoxemia index (percent sleep time with oxyhemoglobin saturation below 90%) were used to quantify the severity of SDB. Brachial artery ultrasound measurements included baseline diameter, percent flow-mediated dilation, and baseline and hyperemic flow velocity and volume. The baseline brachial artery diameter was significantly associated with both the apnea-hypopnea index and the hypoxemia index. The association was diminished by adjustment for body mass index, but remained significant for the apnea-hypopnea index. Age-, sex-, race- and body mass index-adjusted mean diameters were 4.32, 4.33, 4.33, 4.56, 4.53 mm for those with apnea-hypopnea index < 1.5, 1.5-4.9, 5-14.9, 15-29.9, >/= 30, respectively; p = 0.03. Baseline flow measures were associated with the apnea-hypopnea index but this association was non-significant after adjusting for body mass index. No significant association was observed between measures of SDB and percent flow-mediated dilation or hyperemic flow in any model. In conclusion, this study supports a moderate association of SDB and larger baseline brachial artery diameter, which may reflect SDB-induced vascular remodeling. This study does not support a link between SDB and endothelial dysfunction as measured by brachial artery flow-mediated dilation.
authors.affiliation: Department of Medicine, Boston University School of Medicine, The Pulmonary Center, VA Boston Healthcare System, Boston, MA 02118, USA. hchami@bu.edu
authors.forename: Hassan A
authors.initials: HA
authors.lastname: Chami
authors.forename: Michelle J
authors.initials: MJ
authors.lastname: Keyes
authors.forename: Joseph A
authors.initials: JA
authors.lastname: Vita
authors.forename: Gary F
authors.initials: GF
authors.lastname: Mitchell
authors.forename: Martin G
authors.initials: MG
authors.lastname: Larson
authors.forename: Shuxia
authors.initials: S
authors.lastname: Fan
authors.forename: Ramachandran S
authors.initials: RS
authors.lastname: Vasan
authors.forename: George T
authors.initials: GT
authors.lastname: O'Connor
authors.forename: Emelia J
authors.initials: EJ
authors.lastname: Benjamin
authors.forename: Daniel J
authors.initials: DJ
authors.lastname: Gottlieb
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D001783:Blood Flow Velocity; D001916:Brachial Artery / Q000000981:diagnostic imaging / Q000503:physiopathology*; D003430:Cross-Sectional Studies; D005260:Female; D006801:Humans; D006940:Hyperemia / Q000503:physiopathology; D000860:Hypoxia / Q000503:physiopathology; D017078:Laser-Doppler Flowmetry; D008297:Male; D008875:Middle Aged; D017286:Polysomnography; D012039:Regional Blood Flow; D012720:Severity of Illness Index; D012891:Sleep Apnea Syndromes / Q000000981:diagnostic imaging / Q000503:physiopathology*; D014463:Ultrasonography; D014664:Vasodilation