0447 Upper Airway and Surrounding Soft-Tissue Changes During Sleep in Apneics and Controls. (27th April 2018) - Lin, T C
Abstract: Introduction: Previous studies indicated the upper airway narrows in the retropalatal (RP) region during sleep in normal subjects due to thickening of the lateral pharyngeal walls. We hypothesized that apneics would exhibit state-dependent upper airway narrowing in the RP and retroglossal (RG) regions and narrowing in apneics would be greater than controls. Methods: Upper airway MRIs were obtained in 15 sleep-deprived controls (AHI<5; 0.3 ± 0.5 events/hour) and 12 apneics (AHI≥5; 36.2 ± 19.9) during wake and sleep and analyzed for airway measures and soft-tissue movement. We evaluated whether there were significant changes during sleep and if changes differed between groups. Results: Apneics were older (39.2 ± 12.2 vs. 26.4 ± 6.9 years, p=0.005) and more obese (33.0 ± 6.2 vs. 24.2 ± 3.5 kg/m 2, p=0.0003) than controls; 96.3% of subjects were male. In the RP region, controls showed reduced average cross-sectional airway area (CSA; -18.7%, p=0.003) and minimum CSA (-40.5%, p=0.0001), anteroposterior (AP; -25.0%, p=0.0004), and lateral (-17.7%, p=0.037) dimensions. Apneics showed reduced average CSA (-31.3%, p=0.0001) and minimum CSA (-65.4%, p<0.0001), AP (-29.2%, p=0.0016), and lateral (-44.2%, p=0.0004) measures. Apneics had greater reductions in RP minimal CSA (p=0.0204) and lateral dimensions (p=0.0326) than controls. In the RG region, controls showed no significant changes with sleep. Apneics had reductions in minimal CSA (-45.2%, p=0.0011), lateral dimensions (-26.3%, p=0.0137), and trending changes in AP dimension (-18.9%, p=0.070). Reductions in RG minimal CSA (p=0.0096) and lateral dimension (p=0.0291) were greater in apneics than controls. The soft palate (p=0.0451), anterior-superior (p<0.0001), and posterior-inferior (p=0.0113) tongue quadrants exhibited greater posterior movement in apneics. Similar increases in RP lateral wall thickness (p=0.3332) were seen in controls (10.8%, p=0.0214) and apneics (21.8%, p=0.0549). Conclusion: Controls and apneics showed significant reductions in RP airway caliber during sleep, while only apneics showed RG airway changes. Apneics had greater narrowing in both regions compared to controls. State-dependent reductions in AP and lateral airway dimensions are primarily due to posterior movement of the soft palate and tongue and thickening of lateral walls. These data provide important insights into OSA pathogenesis. Support (If Any): Funded by NIH P01 HL094307.