Persistent Treatment-Emergent Central Sleep Apnea (TECSA) Following Hypoglossal Nerve Stimulation

Abstract

Purpose Since 2001, hypoglossal nerve stimulators (HNS) have been used worldwide to treat patients with obstructive sleep apnea (OSA). Recently, a few studies reported treatment-emergent central sleep apnea (TECSA) with spontaneous resolution following HNS. However, the evidence of persistent development of TECSA during long-term care visits was lacking. As a result, this study first report two patients with persistent TECSA and describe their development phenotype during more than two years of follow-up visits to help explore the influencing factors and underlying mechanisms. Patients and Methods This retrospective study included twenty-seven patients who underwent HNS implantation from 2016 to 2021. Their demographic data, pre- and postoperative sleep study characteristics, and device use settings were collected. The possible factors associated with post-operative elevated CSA (central apnea index ≥5) were evaluated. Moreover, the development phenotype of the TECSA was observed and followed up with a titration trial study. Results Among overall 27 patients with OSA, 3 patients with an increased preoperative Epworth Sleepiness Score (ESS) got an elevated CSA (CAI ≥ 5). Two of these 3 patients developed a persistent TECSA with a significant negative correlation between obstructive apnea index (OAI) and central and mixed sleep apnea index (CMAI) (R = −0.745, P = 0.021). These development phenotypes might be associated with different stimulation amplitudes of the HNS device. Furthermore, the following titration trial study also suggested that different amplitudes would influence the development of TECSA following HNS. Conclusion OSA patients with severe daytime sleepiness are more likely to have elevated CSA following HNS. An inappropriate stimulation amplitude might influence the development course of TECSA in such patients.

Response to Hypoglossal Nerve Stimulation Changes With Body Mass Index and Supine Sleep

“…In an exploratory analysis, 2 patients with low preimplantation AHI scores actually experienced worsened AHI postimplantation. One possible explanation for this finding lies in emerging evidence for excessive stimulation voltage during HGNS causing central apnea . It is also notable that both patients had below-average BMI values and both had their preimplantation AHI score measured via an HSAT, which is known to underestimate OSA in those with low BMI .…”

“…One possible explanation for this finding lies in emerging evidence for excessive stimulation voltage during HGNS causing central apnea. 32 It is also notable that both patients had below-average BMI values and both had their preimplantation AHI score measured via an HSAT, which is known to underestimate OSA in those with low BMI. 33 These observations should be interpreted with caution due to the small sample size of only 2 patients and due to the exploratory nature of the analysis.…”