Hypoglossal nerve stimulation therapy on peripheral arterial tonometry in obstructive sleep apnea: a pilot study

Hypoglossal nerve stimulation (HGNS) is being increasingly utilized in the setting of moderate-severe obstructive sleep apnea (OSA). While moderate-severe OSA confers excess cardiovascular risk, the impact of HGNS on cardiovascular requires further investigation. With the advent of peripheral arterial tonometry (PAT), one can non-invasively study real-time changes to the autonomic nervous system. This study evaluates the effect of HGNS therapy on autonomic output, using PAT-integrated polysomnography.

Subjects included adult patients undergoing 2-month post-operative HGNS titration studies with PAT-integrated polysomnography. Apneic and hypopneic events with arousal during stage 2 sleep were identified at increasing levels of stimulation. With each event, PAT signal attenuations were recorded, processed, and analyzed.

Nine subjects were enrolled, and eight met inclusion criteria (mean age 67.8 ± 12.4 years; 50% female). The PAT signal did not significantly change before and during stimulation (mean pre-stimulation 43.4 ± 1.7, mean intra-stimulation 41.1 ± 22.5, p = 0.53) in any patient. The ratio of the PAT signal maximum and minimum amplitudes during sleep breathing events largely demonstrated very weak correlation (R² = <0.12). Across all subjects, poor linear correlation was present between HGNS and PAT signal attenuation (R² = 0.028) in both adjusted and unadjusted analyses.

Using PAT-integrated polysomnography, PAT output does not appear to be affected by HGNS stimulation at clinical thresholds. These findings support the absence of autonomic system alterations by twelfth nerve stimulation and support the clinical use of PAT-based devices for post-HGNS monitoring. Larger studies examining hard cardiovascular endpoints with HGNS are needed.