Examining the impact of multilevel upper airway surgery on the obstructive sleep apnoea endotypes and their utility in predicting surgical outcomes

Abstract

Background and objective Upper airway surgery for obstructive sleep apnoea (OSA) is an alternative treatment for patients who are intolerant of continuous positive airway pressure (CPAP). However, upper airway surgery has variable treatment efficacy with no reliable predictors of response. While we now know that there are several endotypes contributing to OSA (i.e., upper airway collapsibility, airway muscle response/compensation, respiratory arousal threshold and loop gain), no study to date has examined: (i) how upper airway surgery affects all four OSA endotypes, (ii) whether knowledge of baseline OSA endotypes predicts response to surgery and (iii) whether there are any differences when OSA endotypes are measured using the CPAP dial‐down or clinical polysomnographic (PSG) methods. Methods We prospectively studied 23 OSA patients before and ≥3 months after multilevel upper airway surgery. Participants underwent clinical and research PSG to measure OSA severity (apnoea–hypopnoea index [AHI]) and endotypes (measured in supine non‐rapid eye movement [NREM]). Values are presented as mean ± SD or median (interquartile range). Results Surgery reduced the AHITotal (38.7 [23.4 to 79.2] vs. 22.0 [13.3 to 53.5] events/h; p = 0.009). There were no significant changes in OSA endotypes, however, large but variable improvements in collapsibility were observed (CPAP dial‐down method: ∆1.9 ± 4.9 L/min, p = 0.09, n = 21; PSG method: ∆3.4 [−2.8 to 49.0]%Veupnoea, p = 0.06, n = 20). Improvement in collapsibility strongly correlated with improvement in AHI (%∆AHISupineNREM vs. ∆collapsibility: p < 0.005; R2 = 0.46–0.48). None of the baseline OSA endotypes predicted response to surgery. Conclusion Surgery unpredictably alters upper airway collapsibility but does not alter the non‐anatomical endotypes. There are no baseline predictors of response to surgery.

Assessment of Muscular Weakness in Severe Sleep Apnea Patients: A Prospective Study

“…Our institution considered 15 that patients with OSAHS and myofunctional disorders should benefit from treatments before performing any surgery. Wong et al 3 considered surgery should be avoided in this kind of phenotype. We hypothesize that normal or superior IOPI and TDS scores in OSAHS patients are present when the upper airway muscles are “fighting” against an upper airway obstacle.…”

“…One of these is the hypotonic phenotype, which presents impairment of the control and function of the pharyngeal dilator muscle 1 . This phenotype reduces the chance of successful surgical outcomes, 3 and should thus be recognized before defining treatment allowing the clinician to offer a combined therapeutic modality.…”

Contemporary Concise Review 2022: Sleep

“…Messineo et al reported in this journal that the combination of atomoxetine and fesoterodine, an extended release anti‐muscarinic, produced a significant drop in AHI (of >50% to <10 events/h) in a subgroup of patients with milder airway collapsibility 19 . Conversely, a study of 23 patients with OSA demonstrated that, whilst there were large improvements in collapsibility post multi‐level upper airway surgery in some cases, none of the endotype traits predicted response to surgery 20 …”

“…19 Conversely, a study of 23 patients with OSA demonstrated that, whilst there were large improvements in collapsibility post multilevel upper airway surgery in some cases, none of the endotype traits predicted response to surgery. 20 Finally, a hotly debated study showed that mild intermittent hypoxia administered during wakefulness for 5 days/ week for 3 weeks reduced systolic BP and sympathetic activity in a small group of OSA patients concurrently commencing CPAP treatment. 21 Whilst the idea of hypoxia conditioning has been theorized as a therapeutic treatment, this concept needs further testing given the potential deleterious effects of hypoxia.…”

Endotyping in sleep surgery: Not ready for primetime

“…The recent publication by Wong et al 1 in Respirology explores the possibility of utilizing endotypic features in the prediction of adult OSA surgery outcomes. This research is unique in assessing how upper airway surgery influences all four PALM‐defined endotypes, 2 employing two different methodologies (CPAP dial‐down and polysomnography‐derived).…”