(1338) Proximal Hypoglossal Neurostimulation Decreases the Hypoxic Burden in the OSPREY Randomized Clinical Trial

Introduction: Treatment of obstructive sleep apnea (OSA) is highly recommended for many patients to reduce cardiovascular risk and the hypoxic burden (HB), defined by the area under the desaturation curve, has been identified as a superior predictor of major cardiovascular events as compared to the apnea hypopnea index (AHI). The OSPREY randomized controlled trial (RCT) evaluated the outcome of proximal hypoglossal nerve stimulation (pHGNS) for OSA, resulting in significant improvement in the AHI and oximetry metrics for the active and not for the control group. We hypothesized that pHGNS therapy in OSPREY would improve the HB.

Methods: All patients were implanted with the pHGNS device and randomized 2:1 to active treatment or 6-month delay. Polysomnographic outcome was assessed at 6 months and then at 12 months, when all received active treatment. The HB was determined by summing the area under the desaturation curves then normalized by sleep time and compared between baseline and 6 months for treatment (T) vs control (C) groups and then for treatment group at 12 months.

Results: The baseline HB for the 104 OSPREY participants (73.1% male and mean age 55.6yrs) had a mean of 117.9 and median of 104.2 %min/hr. At 6 months the median change was -51.1 vs. -5.8 %min/hr (T vs C, p=0.001). At 12 months therapy in the treatment group, the median HB was reduced to 25.3 resulting in a median relative change of -74% and median absolute change of -55.2 %min/hr.

Conclusions: pHGNS treatment in the OSPREY RCT resulted in clinically and statistically significant reductions of HB in the treatment but not control group at six months. In the active group, further HB reduction was seen at 12 months. Observed improvements in HB may lead to reduced risk of stroke and myocardial infarction, requiring further study and longitudinal follow up.