0535 Impact of hypoglossal nerve stimulation surgery alone on sleep disordered breathing and sleepiness

Abstract Introduction Hypoglossal Nerve Stimulation (HNS) is an established option for CPAP -intolerant obstructive sleep apnea (OSA) patients, with multiple studies demonstrating safety and effectiveness. There are known nightly variations in OSA severity. We aimed to determine if device implant alone (with therapy off) compared to baseline influenced sleep disordered breathing and daytime sleepiness. Methods This was a retrospective analysis of the STAR (Stimulation Therapy for Apnea Reduction) Trial, conducted from 2010-2016, that led to FDA approval HNS. Data was collected at a pre-implant screening, and post-implant prior to device activation (therapy off). Each visit included an attended polysomnography (PSG) and Epworth Sleepiness Scale (ESS). PSGs were scored by a central core lab. Results There were 126 participants (83% male), age 55 ± 10 years. The time between pre-implant baseline screening and device activation visit averaged 88 ± 29 days. BMI was 28 ± 3 at baseline and 28 ± 3 post-implant with therapy off. The pre and post-implant Apnea Hypopnea Index (AHI)s were similar (32 ± 9 vs 32 ± 9 events/hour, p=0.82). The two-night AHI ranged from 13 to 65. The average AHI change between pre-implant and post-implant (therapy off) was -0.3 ± 17 events/hour. The Sher 20 response rate between pre-implant and post-implant therapy off was 13%. By comparison, previously published mean AHI with therapy activated was approximately 10-15 events/hour, and Sher 20 response rates ranged between 65%-75%. ESS pre and post-implant (therapy off) were similar (12 ± 5 vs 11 ± 5, p=0.09), compared to ESS previously reported with HNS therapy activated (typically 6-7). Conclusion The STAR two-night baseline AHIs ranged between 13-65. While there were nightly differences in AHI in some patients, surgical implant of HNS with therapy off, did not result in meaningfully improvement in the AHI, Sher 20 response rate, or ESS. Support (if any) Inspire Medical Systems