1019 New onset OSA after long term Vagus Nerve Stimulator implantation in a patient with Lennox-Gastaut syndrome: A case report

Abstract

Abstract Introduction Implantable vagus nerve stimulation (VNS) is an established treatment for drug resistant epilepsy. New onset obstructive sleep apnea (OSA) is a rare side effect of VNS. There are few studies describing VNS induced sleep apnea in adults. [1-2] A study of 16 patients with drug-refractory epilepsy found 5 patients with normal AHI develop mild OSA after VNS treatment for 3 months. [2] However, no literature exists regarding OSA after long term VNS implantation. Untreated OSA in patients with epilepsy can impact epilepsy outcomes. We report a case of new onset OSA after long term VNS implantation, refractory to PAP therapy. Report of case(s) A 36 year-old man with Lennox-Gastaut syndrome presented with gasping during sleep and daytime hypersomnolence. He underwent VNS implantation at the age of 12. A prior PSG in 2018 showed no sleep apnea. Repeat PSG showed VNS-induced OSA (AHI 10.1/hour). After failed CPAP titration, BPAP-S at 25/16 cm H2O improved OSA. Review of therapy data on follow up showed AHI of 13.7/hour and CAI of 10.9/hour, which is concerning for treatment induced central sleep apnea on BPAP. Diagnostic study with VNS turned off revealed mild OSA (AHI 5.8/hour). A multidisciplinary approach involving ENT for drug-induced sleep endoscopy to optimize VNS stimulation parameters along with neurology and sleep involvement is planned. The optimized VNS setting could be used during planned sleep times using a VNS device with dual-programming capability. Conclusion To our knowledge, there is no literature on development of sleep apnea after long term VNS implantation. Although the exact mechanism is unknown, VNS can cause sleep apnea or worsen sleep apnea in patients with a preexisting diagnosis. [1] This case demonstrates need for continuous monitoring and screening for sleep apnea in patients who have been implanted with VNS, even if baseline and follow up PGSs are normal. Current literature suggests discontinuation of VNS to resolve VNS-induced OSA, but we describe a case here where VNS is needed for ongoing management of epilepsy. Further studies are needed to identify treatment options for patients that cannot discontinue VNS therapy who also cannot be successfully treated with PAP if they develop VNS-induced OSA. Support (if any)