0676 Long-term Effects Of Upper Airway Stimulation For Treatment Of Obstructive Sleep Apnea On Measurements Of Central And Mixed Apneas
Abstract Introduction Upper airway stimulation (UAS) of the hypoglossal nerve for obstructive sleep apnea (OSA) is well-tolerated and results in sustained reduction in the apnea-hypopnea index (AHI). Treatment-emergent CSA is reported to occur in 3.5-19.8% of OSA patients treated with CPAP. We aimed to examine the occurrence or emergence of central and mixed apneas in a cohort of participants that received UAS and were followed for 5 years post implantation. Methods The Stimulation Trial for Apnea Reduction (STAR) was a Phase III trial evaluating the safety and efficacy of UAS for CPAP-intolerant OSA. Major inclusion criteria were CPAP intolerance, AHI between 20-50, less than 25% central and mixed apneas and BMI <= 32. Polysomnography was performed at baseline, 12, 18, 36 and 60-month follow-up. Data were scored by a core lab and was then retrospectively analyzed via the STAR PSG database to measure the evolution of central and mixed apneas on UAS therapy. Results Baseline age was 54.5 ± 10.2 years, BMI was 28.4 ± 2.6 kg/m2 and 83% male (n=126). AHI data were non-normally distributed. Median AHI was 29.3/hr at baseline, that was reduced to 9/hr at 12-months and 6/hr at 60-months. Median central apnea index (CAI) was 0.8/hr at baseline, 0.4/hr at 12-months, and 0.2/hr at 60-months. Median mixed apnea index (MAI) was 0.2/hr at baseline, 0.7/hr at 12-months and 0.4/hr at 60-months. The 12- and 60-month CAI was significantly lower than baseline (p<0.05), but MAI was not. The percentage of central and mixed events remained stable throughout follow-up, approximately at 5% of the total AHI. Conclusion UAS reduced the overall AHI and results in a small but significant decrease in CAI. Given that OSA and CSA frequently co-exist, the role of UAS on reducing CSA in patients with combined OSA and CSA deserves further investigation. Support STAR study was sponsored by Inspire Medical Systems