The prevalence of treatment-emergent central sleep apnea with mandibular advancement device therapy

Exploring the Dose-Response Relationship between Mandibular Protrusion and Respiratory Effort Burden in Oral Appliance Therapy for Obstructive Sleep Apnea

Rationale: Increased respiratory effort (RE) is a critical feature of obstructive sleep apnea (OSA). Although prior studies have established the efficacy of mandibular advancement device (MAD) therapy in reducing the apnea-hypopnea index (AHI), the impact of MAD therapy on RE burden remains unexplored. Objectives: In this study, we used a validated mandibular jaw movement (MJM) monitoring technology to determine the dose-response relationship between MAD protrusion levels and RE burden measured as the percentage of total sleep time (TST) spent in elevated respiratory effort (REMOV) during MAD titration. Methods: Ninety-three patients with OSA eligible for MAD treatment were included in this prospective cohort study. A subjective titration process involved iterative adjustments based on the persistence or worsening of OSA symptoms. Optimal AHI and REMOV responses were defined as an AHI reduction of >50% and a residual REMOV <14% TST, respectively. MJM-based home sleep tests were conducted at initial, intermediate, and final protrusion levels. The treatment effect on REMOV was estimated by regression analysis. Results: AHI and REMOV reductions increased progressively with higher MAD protrusion levels, with AHI decreasing by 10.3, 12.7, and 13.0 events/h and REMOV by 14.5%, 16.8%, and 18.6% TST across the three titration steps. However, a consistent discrepancy was observed between REMOV and AHI responses: at the end of titration, 68.8% of patients achieved optimal responses for both indices, whereas 15.1% had optimal REMOV response without AHI normalization, and 5.4% showed the reverse. Regression analysis showed a significant dose-response relationship for REMOV, with a 10% TST reduction within the 0-6.5 mm protrusion range and diminishing benefits beyond 6.5 mm. Of note, each millimeter advancement would yield a 2.6% TST (95% confidence interval, -3.0% to -2.1%) improvement in REMOV. Conclusions: Our findings demonstrate a dose-response relationship between the MAD protrusion level and the improvement in RE burden. Optimal responses in both AHI and REMOV signify greater efficacy of MAD therapy in reducing obstructive respiratory events and RE burden. This underscores the benefit of using at-home MJM analysis to monitor these two critical metrics in the management of MAD therapy to achieve better clinical outcomes and enhance MAD titration efficacy.

Treatment-emergent central sleep apnea in patients treated with a mandibular advancement device

OBJECTIVES

Treatment-emergent central sleep apnea (TECSA) is well established in continuous positive airway pressure therapy but was barely studied in mandibular advancement device (MAD) treatment. This study aims to evaluate the prevalence of TECSA in patients treated with a MAD and to determine its risk factors and clinical relevance.

MATERIALS AND METHODS

A total of 139 patients from the IRSR Pays de la Loire Sleep Cohort suffering from snores or obstructive sleep apnea syndrome (OSAS) and treated with a custom-made titratable MAD were included. Baseline and follow-up sleep recordings enabled identification of TECSA patients. Comparative analyses were carried out between TECSA and non-TECSA groups to identify potential risk factors. Clinical relevance of TECSA in both groups was assessed through baseline and follow-up Pichot's self-assessment questionnaire for depressive symptoms (QD2A), 36-item short form survey (SF-36) and Epworth Sleepiness Scale (ESS) scores.

RESULTS

According to the definition selected, a prevalence between 0 % and 5.04 % was found for TECSA in the present study. No statistical differences were found in terms of treatment characteristics, sleep architecture, demographic data or comorbid conditions, although there was a trend towards a higher prevalence of arterial hypertension in TECSA-1 than in non-TECSA group (42.9 % vs 25.4 % respectively, p = 0.379). Baseline ESS showed a trend towards a higher score in TECSA-1 patients compared to non-TECSA patients (13/24 vs 10/24 respectively, p = 0.074), with a high proportion of TECSA-1 patients suffering from excessive daytime sleepiness before initiation of treatment (85.7 %, vs 52.4 % in non-TECSA patients, p = 0.124). No statistical differences were found regarding delta Pichot's QD2A and ESS scores between baseline and follow-up although there was a trend towards higher ESS scores at follow-up in TECSA-1 group compared to non-TECSA patients. Median delta SF-36 score for the General health scale was significantly lower in TECSA-1 and there was a trend towards lower scores for Mental health category in TECSA-1 patients.

CONCLUSIONS

TECSA is a rare phenomenon that can occur in patients treated with a MAD for an OSAS. Clinical, polysomnographic and treatment-related risk factors have yet to be reassessed in larger cohorts. These findings suggest probably poorer subjective clinical outcomes in terms of sleepiness and quality of life in patients with MAD-related TECSA.

OSA pathophysiology: a contemporary update

Defined as an elevated frequency of obstructive respiratory events in sleep, obstructive sleep apnoea (OSA) is driven by a combination of four pathophysiologic mechanisms: elevated upper airway collapsibility, unstable ventilatory control, impaired upper airway dilator muscle responsiveness and decreased arousal threshold. Established therapies such as continuous positive airway pressure (CPAP) and oral appliance therapy (OAT) work chiefly through targeting elevated collapsibility, which affects the majority of OSA patients. However, many patients respond poorly or do not tolerate these 'anatomic' therapies. The emerging field of 'precision sleep medicine' seeks to determine if novel treatment approaches specifically targeting the other, 'non-anatomic' mechanisms will improve treatment efficacy and acceptance. In this review, we consider the concepts underlying each pathophysiologic mechanism, the predisposing factors, and the potential implications for established and future OSA treatments.