Upper airway collapsibility during rapid eye movement sleep tracks the response to upper airway surgery for obstructive sleep apnea

Objectives: Endotype-based intervention has shown promise in treatment for patients with obstructive sleep apnea, and upper airway surgery is an important therapeutic option. However, the response to surgery varies among patients with obstructive sleep apnea. This study aims to examine changes in endotypic traits following upper airway surgery and their association with surgical outcome.

Methods: We prospectively recruited 25 patients with obstructive sleep apnea who visited a single sleep center for upper airway surgery and completed polysomnographic studies both before and following surgery. Endotypic traits during non-rapid eye movement and rapid eye movement sleep - including collapsibility (Vpassive), arousal threshold, loop gain, and upper airway compensation - were estimated using the Phenotyping Using Polysomnography method. Patients were classified as responders or non-responders based on improvements in the apnea-hypopnea index, and we compared pre-surgery endotypic traits between them using Mann-Whitney tests. Changes in pre- and post-surgery endotypic traits between responders and non-responders were compared using generalized linear mixed models.

Results: We identified 12 responders and 13 non-responders. Compared to non-responders, collapsibility during rapid eye movement sleep improved in responders (22.3 vs. - 8.2 %eupnea Vpassive, p = 0.01), and the arousal threshold decreased during non-rapid eye movement sleep in responders (-22.4 %eupnea, p = 0.02). No endotypic trait predicted surgical response, but AHI during rapid eye movement sleep was higher among responders than non-responders (51.8 vs. 34.4/h, p = 0.05).

Conclusion: Upper airway surgery significantly reduced collapsibility during rapid eye movement sleep among responders. The target pathology for upper airway surgery is a compromised upper airway during rapid eye movement sleep.