0637 Enhancing Response to Proximal Hypoglossal Nerve Stimulation (pHGNS) with Paired Rather than Single Electrode Stimulation in Moderate to Severe OSA

Abstract Introduction The THN3 and OSPREY randomized clinical trials (RCT) demonstrated substantial improvements in moderate to severe obstructive sleep apnea (OSA), sleep architecture and quality of life in actively treated vs. sham controls. Both trials rotated stimulation of selected single electrodes from six circumferentially arranged cuff electrodes. We hypothesized that further reductions in apnea-hypopnea index (AHI) could be achieved in OSPREY non-responders by simultaneously stimulating electrode pairs and activating greater portions of the lingual musculature. Methods 26 OSA patients (age: 53.8±8.9yr; sex: 22M, 4F; BMI: 31.9±2.4kg/m2; AHI: (38.3±13.3/hr) whose endpoint AHI did not meet Sher’s responder criteria were recruited for paired-contact stimulation. A rotating sequence of contact pairs was assembled from single contacts that previously demonstrated either neutral or increased airflow during sleep when stimulated (“PolySync”). Electrode pairs were titrated during polysomnography (PSG), followed by acclimatization for ≥3 weeks. Therapeutic effectiveness was determined thereafter on an unmanipulated PSG. AHI changes from Baseline were compared for (a) single- vs. paired-contact pHGNS nights, and for (b) paired-contact pHGNS vs. Controls nights (to account for night-to-night AHI variability). Results Of 26/35 Sher non-responders, 14 completed the retitration protocol to date. PolySync achieved a Sher AHI response in 10/14 (71%). AHI reduction was substantially larger in paired than single pHGNS regimens (-19.7±17.6/hr vs. -3.0±15.5/hr, respectively) and compared to that of Controls (+1.7±16.7/hr). Of note, Baseline AHI in paired-pHGNS and Controls were similar (38.3±13.3/hr vs. 36.1±12.0/hr). Conclusion Paired-electrode pHGNS applied via PolySync algorithm markedly improved AHI responses over single-contact stimulation in the OSPREY RCT. Paired pHGNS converted the majority of non-responders into responders, well beyond that expected from night-to-night AHI variability. Improved paired responses may be attributed to (a) greater comfort at lower stimulation amplitudes and (b) broader activation of the tongue musculature by fixing tongue shape, stiffness and extent of tongue protrusion. Support (if any) Supported by LivaNova Inc.