Upper-airway stimulation for obstructive sleep apnea

Neurostimulation for Obstructive Sleep Apnea

Neurostimulation of hypoglossal nerve has emerged as an effective treatment option of obstructive sleep apnea (OSA). Since FDA approval in 2014, therapy has been widely used in select patients with moderate-to-severe OSA who do not benefit from positive airway pressure. Ongoing research and technological developments continue to advance the therapy to deliver personalized and efficient treatment to patients with OSA.

Health Inequalities in the Diagnosis and Treatment of Obstructive Sleep Apnea in Children and Adults

Our understanding of the prevalence of obstructive sleep apnea (OSA) in the United States is confounded by significant inequalities in diagnosis and treatment based on gender, race and socioeconomic status. Health literacy and cultural norms contribute to these inequities. Large gaps in data exist, as certain populations like Native Americans, Pacific Islanders, and sexual minorities have been sparsely studied, or not at all. Future research should aim to develop more inclusive diagnostic strategies to address OSA in diverse populations.

Advanced Diagnostic Techniques in Obstructive Sleep Apnea

Optimal surgical and medical management of obstructive sleep apnea requires clinically reliable identification of patterns and sites of upper airway obstruction. A wide variety of modalities have been used to evaluate upper airway obstruction. Drug-induced sleep endoscopy (DISE) and cine MRI are increasingly used to identify upper airway obstruction sites, to characterize airway obstruction patterns, to determine optimum medical and surgical treatment, and to plan individualized surgical management. Here, we provide an overview of the applications of DISE and cine MRI in assessing upper airway obstruction in children and adults with obstructive sleep apnea.

Assessment and management of continuous positive airway pressure therapy in patient with obstructive sleep apnea

Obstructive sleep apnea (OSA) causes excessive daytime sleepiness, impaired daytime functioning, and an increased risk of cardiovascular diseases. Continuous positive airway pressure (CPAP) is a highly effective therapy for moderate to severe OSA. Although CPAP adherence is commonly assessed using a 4-hthreshold, determining the optimal usage time based on clinical outcomes is crucial. While subjective sleepiness often improves with ≥4 h of CPAP usage, an extended duration (≥6 h) may be necessary to impact objective sleepiness. CPAP demonstrated a modest yet clinically meaningful dose-dependent effect on lowering blood pressure. For patients seeking antihypertensive benefits from CPAP therapy, the goal should extend beyond 4 h of use to maximize the therapeutic impact. Recognizing individual variations in sleep duration and responses to CPAP therapy is essential. The adoption of 'individualized goals for CPAP use,' outlining target times for specific outcomes, should also consider an individual's total sleep duration, including periods without CPAP. The impact of CPAP on clinical outcomes may vary, even with the same duration of CPAP use, depending on the period without CPAP use, particularly during the first or second half of sleep. Patients who remove or initiate CPAP midway or have a low CPAP usage frequency may require different forms of guidance. Tailoring patient education to address CPAP usage patterns may be necessary to enhanced satisfaction, self-efficacy, and adherence to therapy. Management of CPAP treatment should be personalized to meet individual needs and adapted based on specific response patterns for achieving treatment efficacy.

Cephalometric Screening Assessment for Superior Airway Space Narrowing-Added Value of Three-Dimensional Imaging

Background: Assessing the morphology of the superior airway space is a crucial diagnostic step in the treatment planning of patients with obstructive sleep apnea syndrome (OSAS) or prior to orthognathic surgery. The aim of this study is to evaluate the necessary scope of a two-dimensional cephalometric assessment and the necessity of three-dimensional imaging in the identification of superior airway space narrowing (SASN). Methods: The computed tomography studies of 100 non-obese, non-OSAS patients were evaluated and analyzed retrospectively. Multiplanar reconstructions were created and underwent cephalometric evaluation. The three-dimensional superior airway morphology was segmented and measured for the minimal cross-sectional area (Amin) and volume (V0). Patients were grouped according to Amin < 80 mm2 and V0 < 12 cm3. Cephalometric parameters (CPs) were analyzed according to Amin and V0 with an unpaired t-test, Pearson correlation, and ROC-curve analysis. Results: The CPs regarding sagittal airway space dimensions (IPAS, MPAS, SPAS) and mandibular body length (GoGn) show the strongest correlation to the three-dimensional minimal cross-sectional area (Amin). The ROC-curve analysis classifying for SASN led to an AUC of 0.86 for IPAS, 0.87 for MPAS, 0.88 for SPAS, and 0.63 for GoGn. Three-dimensional imaging may further improve the diagnostic accuracy in the identification of SASN for IPAS below 13.5 mm, MPAS below 10.2 mm, SPAS below 12.5 mm, and GoGn below 90.2 mm. Conclusions: Two-dimensional cephalometric sagittal airway space diameters and mandibular body length are useful initial screening parameters in the identification of superior airway space narrowing. Nevertheless, as the correlation of two-dimensional cephalometric parameters with three-dimensional upper airway space narrowing is varying and highly dependent on acquisition circumstances, indications for three-dimensional imaging, if possible, in the supine position to evaluate upper airway space morphology should be provided generously, especially in patients with low but normal airway space parameters in two-dimensional cephalometry.

A randomized controlled crossover trial of acute intermittent and continuous hypoxia exposure in mild-moderate obstructive sleep apnea: A feasibility study

In a prospective, randomized, controlled crossover study, we explored the effects of acute intermittent hypoxia and acute continuous hypoxia on patients with mild-moderate obstructive sleep apnea. Over three single-night sessions, subjects were alternately exposed to normoxia, acute continuous hypoxia and acute intermittent hypoxia before sleep. The apnea-hypopnea index and oxygen desaturation index were used to diagnose obstructive sleep apnea and evaluate efficacy. A responder was defined as a participant with a ≥ 50% reduction in apnea-hypopnea index between normoxia and hypoxia exposure. Sixteen participants with mild-moderate obstructive sleep apnea completed the study. Compared with normoxia, the mean apnea-hypopnea index decreased by 8.9 events per hr (95% confidence interval, 4.2-13.6, p = 0.001) with acute intermittent hypoxia and by 4.1 events per hr (95% confidence interval, 0.5-8.8, p = 0.082) with acute continuous hypoxia, equating to a mean decrease in apnea-hypopnea index of 4.8 events per hr (95% confidence interval, 0.1-9.5, p = 0.046) with acute intermittent hypoxia compared with acute continuous hypoxia. Compared with normoxia, the mean oxygen desaturation index decreased by 9.8 events per hr (95% confidence interval, 4.4-15.1, p = 0.001) with acute intermittent hypoxia but did not significantly decrease with acute continuous hypoxia; the mean oxygen desaturation index decreased by 7.2 events per hr (95% confidence interval, 1.8-12.6, p = 0.010) with acute intermittent hypoxia compared with acute continuous hypoxia. Of the 16 participants, 11 responded to acute intermittent hypoxia and four responded to acute continuous hypoxia (p = 0.032), of whom eight of 11 cases and all four cases had oxygen desaturation indexes <5 events per hr, respectively (p = 0.273). All participants tolerated acute intermittent hypoxia and there were no obvious adverse events during acute intermittent hypoxia exposure. In conclusion, acute intermittent hypoxia exposure improved apnea-hypopnea index and oxygen desaturation index in patients with mild-moderate obstructive sleep apnea, suggesting that further prospective validation of intermittent hypoxia exposure in patients with obstructive sleep apnea is needed to establish its clinical feasibility as a therapeutic modality.

Treatment of obstructive sleep apnea after chemoradiation therapy for advanced head and neck cancer

This report presents a case of worsening obstructive sleep apnea (OSA) post-chemoradiation therapy that improved significantly after placement of a hypoglossal nerve stimulator. The patient was a 66-year-old male, diagnosed with head and neck cancer, who experienced exacerbation of OSA after receiving chemoradiation. A hypoglossal nerve stimulator was placed, with minimal complications. The patient showed a significant improvement in OSA as exhibited by the reduction in apnea-hypopnea index. Hypoglossal nerve stimulator placement appears to be a potential treatment option for induced or worsened OSA, which is a known complication of head and neck cancer treatment. When considering treatment options, upper airway stimulation is indeed a possible method in patients who meet the recommended guideline criteria.

Sleep status of older adults with sleep apnoea syndrome may vary by body mass index

Obesity and ageing are the most important risk factors for sleep apnoea syndrome (SAS); however, the role of body mass index (BMI) on sleep status in healthy older adults is unclear. To explore sleep parameters according to BMI among active older adults, we cross-sectionally examined the relationship between sleep-related parameters and BMI in 32 Japanese adults aged from 83 to 95 years without long-term care who were unaware of having SAS. Correlation and linear regression analyses were performed. Moderate or severe SAS prevalence was high in both those with low (68.8%) and high (68.8%) BMI. A higher increase in apnoea-hypopnoea index (AHI) was negatively correlated with sleep depth in the high-BMI group. In the low-BMI group, the number of awakenings and age were positively correlated with AHI. Older adults may have SAS regardless of their BMI, and the sleep status of patients with SAS may vary by BMI.

Sleep-disordered breathing in heart failure

PURPOSE OF REVIEW

This review addresses the evolving intersection of sleep-disordered breathing (SDB) and heart failure, a topic of increasing clinical significance due to the high prevalence of SDB in heart failure patients and its impact on morbidity and mortality. It reflects recent advancements in diagnostic methodologies and therapeutic strategies. It emphasizes the need for heightened awareness among healthcare providers about the complex relationship between SDB and various forms of heart failure.

RECENT FINDINGS

Recent studies underscore the high incidence of SDB in heart failure patients, varying with the cause of heart failure. Emerging diagnostic tools, including home sleep tests and advanced inpatient screening methods, have improved the early detection and accurate diagnosis of SDB. Novel treatment modalities, like hypoglossal and phrenic nerve stimulation, are promising, especially where conventional therapies are inadequate. The review also discusses the complexities of managing SDB in the context of different heart failure subtypes.

SUMMARY

Findings from recent literature suggest that improved screening, diagnosis, and innovative treatment of SDB in heart failure patients can reduce morbidity, mortality, and healthcare costs. This review emphasizes the need for personalized treatment approaches tailored to individual patient profiles, highlighting the potential of new technologies and multidisciplinary strategies in clinical practice.

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

Importance

Hypoglossal nerve stimulation (HGNS) is a potential alternative therapy for obstructive sleep apnea (OSA), but its efficacy in a clinical setting and the impact of body mass index (BMI; calculated as weight in kilograms divided by height in meters squared) on treatment response remain unclear.

Objective

To investigate whether HGNS therapy is effective for patients with OSA, whether HGNS can treat supine OSA, and whether there are associations between BMI and treatment response.

Design, Setting, and Participants

In this cohort study, adult patients with OSA implanted with HGNS at the Washington University Medical Center in St Louis from April 2019 to January 2023 were included. Data were analyzed from January 2023 to January 2024.

Exposure

HGNS.

Main Outcomes and Measures

Multivariable logistic regression was performed to assess associations between HGNS treatment response and both BMI and supine sleep. Treatment response was defined as 50% reduction or greater in preimplantation Apnea-Hypopnea Index (AHI) score and postimplantation AHI of less than 15 events per hour.

Results

Of 76 included patients, 57 (75%) were male, and the median (IQR) age was 61 (51-68) years. A total of 59 patients (78%) achieved a treatment response. There was a clinically meaningful reduction in median (IQR) AHI, from 29.3 (23.1-42.8) events per hour preimplantation to 5.3 (2.6-12.3) events per hour postimplantation (Hodges-Lehman difference of 23.0; 95% CI, 22.6-23.4). In adjusted analyses, patients with BMI of 32 to 35 had 75% lower odds of responding to HGNS compared with those with a BMI of 32 or less (odds ratio, 0.25; 95% CI, 0.07-0.94). Of 44 patients who slept in a supine position, 17 (39%) achieved a treatment response, with a clinically meaningful reduction in median (IQR) supine AHI from 46.3 (33.6-63.2) events per hour preimplantation to 21.8 (4.30-42.6) events per hour postimplantation (Hodges-Lehman difference of 24.6; 95% CI, 23.1-26.5). In adjusted analysis, BMI was associated with lower odds of responding to HGNS with supine AHI treatment response (odds ratio, 0.39; 95% CI, 0.04-2.59), but the imprecision of the estimate prevents making a definitive conclusion.

Conclusions and Relevance

This study adds to the growing body of literature supporting the use of HGNS for OSA treatment. Sleep medicine clinicians should consider informing patients that higher BMI and supine sleeping position may decrease therapeutic response to HGNS. Future research is needed to replicate these findings in larger, more diverse cohorts, which would facilitate the optimization of treatment strategies and patient counseling for HGNS therapy.

Troubleshooting Upper Airway Stimulation Therapy Using Drug-Induced Sleep Endoscopy

OBJECTIVE

This study assesses the utility of drug-induced sleep endoscopy (DISE) in guiding further treatment for patients with obstructive sleep apnea (OSA) who have difficulty tolerating upper airway stimulation (UAS) or have inadequate response to therapy.

STUDY DESIGN

We conducted a retrospective analysis of UAS patients at our institution who underwent DISE, post-UAS, and evaluated the efficacy of different electrode configurations and maneuvers.

SETTING

A tertiary care hospital.

METHODS

Out of 379 patients who received UAS therapy, 34 patients who underwent DISE post-UAS (DISE-UAS) were included. Palatal coupling (PC) was assessed with UAS stimulation alone, jaw thrust alone, and both simultaneously during DISE.

RESULTS

Among 34 patients, 5 had suboptimal adherence to UAS therapy, 19 had suboptimal therapy efficacy with residual OSA burden, and 10 had both. During DISE-UAS, PC was observed in 7 patients (21%) with UAS stimulation alone, 9 patients (26%) with jaw thrust alone, and 8 patients (24%) with both maneuvers combined. Notably, 10 patients (29%) did not exhibit PC with any maneuver. Based on DISE-UAS findings, 13 patients were recommended oral appliance therapy (OAT), and 8 patients underwent further surgical interventions.

CONCLUSION

DISE-UAS is a valuable adjunct in troubleshooting UAS therapy for patients intolerant to CPAP or with suboptimal therapy efficacy. This study provides an algorithm for targeted multimodality therapy based on DISE findings, facilitating personalized management approaches.

The Repeatability of Pharyngeal Opening Pressure Under Drug-Induced Sleep Endoscopy

OBJECTIVE

Pharyngeal opening pressure (PhOP) is a measure of upper airway collapsibility that can be obtained during drug-induced sleep endoscopy (DISE) using a continuous positive airway pressure (CPAP) titration. However, the stability of PhOP over the course of sedation during DISE remains unclear. This study aims to compare repeat measures of PhOP over the course of DISE.

STUDY DESIGN

Single arm prospective study.

SETTING

Single tertiary care institution.

METHODS

Patients had 2 CPAP titrations while undergoing DISE. Collected data included patient demographics, PhOP, patient sedation index (PSI), and duration of and between CPAP titrations. t Tests, test-retest coefficient analysis, and repeated measures correlation were performed.

RESULTS

Twenty-five patients completed the study between 2022 and 2023 with 22 patients having sedation depth (PSI) recording. Most were male (76%), obese (average body mass index: 30.24 kg/m2), with severe obstructive sleep apnea (average apnea-hypopnea index: 39.8 events/hr). Test-retest analysis showed good-excellent correlation between PhOP values (intraclass correlation coefficient = 0.892, P < .0001, n = 25). Average time between CPAP titrations was 15 minutes to 6 seconds. Over that time, PhOP increased by an average of 0.72 cmH2O (P = .06, n = 25) and PSI decreased by 9.5 units (P = .01, n = 22). Repeated measures correlation showed a weak negative correlation between PhOP and PSI (r = -.45, P = .03, n = 22).

CONCLUSION

The results showed repeatability of PhOP values over the course of DISE. When adjusted for sedation depth (PSI), deeper sedation was weakly associated with greater PHOP. However, the magnitude of this change was small and we conclude that PhOP remains relatively stable over the course of DISE (Effects of Lung Volume on Upper Airway Patency During DISE [DISE-Pulm], NCT05350332, clinicaltrials.gov).

Effects of respiratory exercises in sleep bruxism and associated obstructive sleep apnea: a double-blind, placebo-controlled randomized clinical trial

PURPOSE

The aim of this study is to assess the effects of respiratory exercises (inspiratory and expiratory) in individuals with sleep bruxism (SB) and associated obstructive sleep apnea (OSA).

METHODS

This is a double-blind, placebo-controlled randomized clinical trial including individuals with SB and associated respiratory events in OSA. Respiratory physical therapy was performed using inspiratory (Threshold® IMT), expiratory (Threshold® PEP) muscle training, and compared with a placebo group. A total of 30 daily respiratory cycles (inspiration and expiration) were performed five times a week for 12 weeks. Individuals were reassessed at two times, at baseline (T1) and after 12 weeks of training (T2) by means of the Pittsburgh Sleep Quality Index and Polysomnography.

RESULTS

Awakening was significantly different (p ≤ 0.05) between the inspiratory group and placebo 12 weeks after respiratory physical therapy. The number of contractions of the masseter muscle differed between the inspiratory, expiratory, and placebo groups (p ≤ 0.05).

CONCLUSION

Respiratory physical therapy for OSA improved awaking levels in 80 and 67% of the number of masseter muscle contractions, when compared to placebo.

TRIAL REGISTRATION

Brazilian Registry of Clinical Trials (No. RBR-9F6JKM).

Concurrent laparoscopic sleeve gastrectomy with uvulopalatopharyngoplasty in the treatment of morbid obesity comorbid with severe obstructive sleep apnea: a retrospective cohort study

STUDY OBJECTIVES

This study aimed to evaluate the safety and short-term effect of contemporaneous surgeries (bariatric surgery plus uvulopalatopharyngoplasty [UPPP]) in the treatment of morbid obesity comorbid with severe obstructive sleep apnea (OSA).

METHODS

A retrospective cohort study was performed to identify patients with obesity and severe OSA who underwent laparoscopic sleeve gastrectomy (LSG) with or without UPPP surgeries between December 2019 and December 2021 in our center. Patients were divided into 2 groups according to different surgical methods (contemporaneous group [LSG with UPPP] vs LSG-only group). Data about surgical safety, OSA remission, and effectiveness of weight loss were collected and analyzed between the 2 groups before and 12 months after surgery.

RESULTS

A total of 101 patients were included in this study (contemporaneous group [LSG with UPPP], n = 42 vs LSG only group, n = 59). There was no significant difference in surgical safety between the 2 groups, and both OSA and obesity were significantly improved at 12.5 ± 2.1 months postoperative follow-up. The apnea-hypopnea index decreased from 68.7 ± 30.4 events/h to 10.2 ± 7.0 events/h in the contemporaneous group (P < .001) and from 64.7 ± 26.2 events/h to 18.9 ± 9.8 events/h in the LSG group (P < .001). Moreover, the apnea-hypopnea index decreased to below 5 events/h in 50% of patients (21/42) in the contemporaneous group but only in 13.5% of patients in the LSG group (P < .001). In the LSG group 20 (34%) patients achieved a reduction in apnea-hypopnea index < 15 events/h and resolution of daytime sleepiness.

CONCLUSIONS

Contemporaneous surgery (concurrent bariatric and UPPP surgeries) is feasible and an effective option for patients with obesity and severe OSA. However, our finding suggests that approximately a third of patients undergoing LSG with UPPP may not derive significant benefit from the UPPP portion of the contemporaneous surgical approach.

CITATION

Yang C, Yu W, Yao K, et al. Concurrent laparoscopic sleeve gastrectomy with uvulopalatopharyngoplasty in the treatment of morbid obesity comorbid with severe obstructive sleep apnea: a retrospective cohort study. J Clin Sleep Med. 2024;20(4):555-564.

Right Versus Left Cuff Position for Upper Airway Stimulation

OBJECTIVE

Upper airway stimulation (UAS) is a treatment option for obstructive sleep apnea in which electrical stimulation is applied to the hypoglossal nerve. Nerve branches that control tongue protrusion are located inferiorly. Due to positioning, left-sided implants are typically placed with an inferiorly oriented electrode cuff (L-down) as opposed to superiorly on the right (R-up). In this study, we assess the impact of left- versus right-sided UAS on patient outcomes.

STUDY DESIGN

Retrospective cohort study.

SETTING

Tertiary Academic Medical Center.

METHODS

Patients who underwent UAS implantation between 2016 and 2021 with an L-down or R-up oriented cuff as confirmed by X-ray were included. Data were collected retrospectively. Most recent sleep study variables were used for analysis.

RESULTS

A total of 190 patients met the inclusion criteria. The average age was 61.0 ± 11.0 years, with 55 (28.9%) females. L-down orientation was present in 21 (11.1%) patients vs 169 (88.9%) R-up. Indications for L-down included hunting/shooting (n = 15), prior radiation/surgery (n = 4), central port (n = 1), and brachial plexus injury (n = 1). Adherence was higher among L-down patients (47.1 vs 41.0 hours use/week, P = .037) in univariate analysis, with a similar time to adherence data collection (4.4 vs 4.2 months, P = .612), though this finding was not maintained in the multivariate regression analysis. Decrease in apnea-hypopnea index (21.3 vs 22.8, P = .734), treatment success (76.5% vs 84.0%, P = .665), functional threshold (1.5 vs 1.6, P = .550), therapeutic amplitude (2.3 vs 2.4, P = .882), and decrease in Epworth Sleepiness Scale (4.9 vs 2.6, P = .060) were not significantly different between cohorts.

CONCLUSION

This study is the first to examine the orientation of the UAS electrode cuff concerning the electrodes' natural position and the potential effect on postoperative outcomes. Our study found no significantly different treatment outcomes between the L-down versus R-up cohort, with the exception of device adherence, which was significantly higher in the L-down group on univariate analysis though not on multivariate analysis. Future studies with larger patient cohorts are needed to further investigate this potential relationship between treatment outcomes and electrode cuff orientation.

Relationship of Nocturnal Insomnia Symptoms and Outcomes After Hypoglossal Nerve Stimulation

Objective

In patients undergoing hypoglossal nerve stimulation (HGNS), we examined the Insomnia Severity Index (ISI) to understand how baseline sleep onset insomnia (SOI), sleep maintenance insomnia (SMI), and early morning awakening (EMA) affected postsurgical outcomes.

Study Design

Observational.

Setting

Multicenter registry.

Methods

We included patients from the Adherence and Outcomes of Upper Airway Stimulation for Obstructive Sleep Apnea International Registry (ADHERE) with a baseline ISI from 2020 to 2023. Regression analysis examined the association of ISI question scores for SOI, SMI, and EMA and outcomes: Apnea-Hypopnea Index (AHI) reduction, device usage, changes in the Epworth Sleepiness Scale (ESS) and overall ISI score, final visit (FV) completion, and satisfaction.

Results

No relationship was noted between insomnia subtypes and AHI reduction or FV completion. In the subgroup of patients with baseline moderate/severe insomnia, patients with major impairment for SOI used their device 64 min/day longer than those with minimal impairment. Among all patients, those with baseline major impairment for SOI had a 2.3 points greater improvement in ISI from baseline to FV compared to patients with minimal impairment, while patients with baseline major impairment for SMI had a 2.0 and 3.5 points greater improvement in the ESS and ISI than those with minimal impairment. Patients with EMA and moderate/severe baseline insomnia had decreased odds of being satisfied after surgery.

Conclusion

In ADHERE, nocturnal symptoms of insomnia did not limit HGNS efficacy or therapy use. Conversely, those with worse insomnia subtype impairments at baseline had improved outcomes related to adherence, sleepiness, and insomnia at the FV.

Impact of Hypoglossal Nerve Stimulation on Consumer Sleep Technology Metrics and Patient Symptoms

OBJECTIVES

Obstructive sleep apnea (OSA) is usually assessed at discrete and infrequent timepoints. Wearable consumer sleep technologies (CST) may allow for more granular and longitudinal assessments of OSA therapy responses and OSA-related symptoms.

METHODS

In this case series, we enrolled hypoglossal nerve stimulator (HGNS) patients who had an effective treatment response for an 8-week study using a wearable CST. Participants started with "HGNS-on," were randomized to turn off HGNS therapy during either week 4 or 5 ("HGNS-off"), followed by a return to therapy, "HGNS-resume." Participants completed validated symptom questionnaires assessing sleepiness, insomnia symptoms, functional status, and overall sleep health (Satisfaction, Alertness, Timing, Efficiency, and Duration, SATED) each week. CST metrics and survey scores were compared between HGNS treatment phases. Associations between CST metrics and survey scores were assessed.

RESULTS

Seven participants with a total of 304 nights of CST data showed no statistically significant changes in total sleep time (TST), wake time after sleep onset, or sleep efficiency (SE) across the study periods. During HGNS-off, survey scores indicated significantly worsened OSA-related symptom scores. Two participants had significantly higher heart rate variability (HRV) during HGNS-off (by 3.3 and 6.3 ms) when compared to HGNS active therapy periods. Amongst CST metrics, SATED scores correlated with TST (r = 0.434, p < 0.0001), HRV (r = -0.486, p < 0.0001), and SE (r = 0.320, = 0.0014). In addition, FOSQ-10 scores correlated with average HR during sleep (r = -0.489, p < 0.001).

CONCLUSION

A 1-week HGNS therapy withdrawal period impacted OSA-related sleep symptoms. Sleep-related metrics measured by a wearable CST correlated with symptom scores indicating potental value in the use of CSTs for longitudinal sleep-tracking in OSA patients.

LEVEL OF EVIDENCE

4 Laryngoscope, 2024.

Advanced Diagnostic Techniques in Obstructive Sleep Apnea

Optimal surgical and medical management of obstructive sleep apnea (OSA) requires clinically reliable identification of patterns and sites of upper airway obstruction. A wide variety of modalities has been used to evaluate upper airway obstruction. Drug-induced sleep endoscopy (DISE) and cine MRI are increasingly used to identify upper airway obstruction sites, to characterize airway obstruction patterns, to determine optimum medical and surgical treatment, and to plan individualized surgical management. Here, the authors provide an overview of the applications of DISE and cine MRI in assessing upper airway obstruction in children and adults with OSA.

Safety of Ambulatory Surgery For Obstructive Sleep Apnea: A Retrospective Review

OBJECTIVE

Assess the safety of ambulatory surgery performed for obstructive sleep apnea.

STUDY DESIGN

Retrospective chart review.

SETTING

Tertiary care hospital.

METHODS

Demographic data including age, gender, race, body mass index, insurance status, socioeconomic status, and distance traveled for surgery was collected, as well as comorbidities, and apnea-hypopnea index (AHI). Outcome variables included continuous positive airway pressure reinitiation, planned/unplanned postoperative admission, emergency department (ED) presentation, or readmission within 7 and 14 days of surgery.

RESULTS

A total of 601 patients were included, who underwent sleep surgery between 2017 and 2022. The median age was 55 years [interquartile range: 19]. A total of 437 patients (73%) were male, 502 (84%) were Caucasian, and the median distance traveled was 20 miles [27]. The median AHI was 27.1 [26]. A total of 286 hypoglossal nerve stimulators, 12 tonsillectomies, 160 expansion sphincteroplasties (ESP), and 201 nasal procedures were performed. There were 9 (1%) planned and 23 (4%) total admissions postoperatively. Sixteen patients (2%) presented to ED within 7 days, and 22 (3%) within 14 days. Nine (1%) were readmitted within 7 days, and 12 (2%) within 14 days. There were significantly more planned admissions, unplanned admissions, ED presentations, and readmissions for ESP. There were no significant differences in demographic or clinical data between patients who underwent single versus multiple surgeries.

CONCLUSION

Outpatient sleep surgery is generally safe. Close postoperative monitoring is necessary and overnight observation should be considered in those with very severe sleep apnea and/or significant comorbidities. The distance a patient travels should also be considered for overnight admission.

Effect of hypoglossal nerve stimulation on snoring: an evaluation using objective acoustic parameters

STUDY OBJECTIVES

Hypoglossal nerve stimulation is an established therapy for sleep apnea syndrome. Whether or not this therapy on snoring and nighttime noise exposure is effective and how strong this effect may be has not been objectively investigated thus far and was the aim of this study.

METHODS

In 15 participants (14 males; age: 30-72 years; mean: 51.7 years), polysomnography and acoustic measurements were performed before and after hypoglossal nerve stimulation.

RESULTS

The therapy led to a significant improvement in sleep apnea (apnea-hypopnea index from 35.8 events/h to 11.2 events/h, P < .001). Acoustic parameters showed a highly significant reduction in the average sound pressure level (42.9 db[A] to 36.4 db[A], P < .001), averaged sound energy, A-weighted (LAeq; 33.1 db[A] to 28.7 db[A], P < .001), snoring index (1,068 to 506, P < .001), percentage snoring time (29.7-14.1%, P < .001), and psychoacoustic snore score, the latter being a measure of annoyance due to snoring (47.9 to 24.5, P < .001).

CONCLUSIONS

This study was able to show for the first time by means of objective acoustic and psychoacoustic parameters that hypoglossal nerve stimulation can not only cause a significant improvement in sleep apnea but also has a positive effect on snoring and thus noise annoyance experienced by the bed partner.

CLINICAL TRIAL REGISTRATION

Registry: German Clinical Trials Register; Name: Effect of Hypoglossal Nerve Stimulation on Snoring: An Evaluation Using Objective Acoustic Parameters; URL: https://drks.de/search/de/trial/DRKS00032354; Identifier: DRKS00032354.

CITATION

Fischer R, Vielsmeier V, Kuehnel TS, et al. Effect of hypoglossal nerve stimulation on snoring: an evaluation using objective acoustic parameters. J Clin Sleep Med. 2024;20(3):363-370.

Mitigating Infection Risk in Upper Airway Stimulation

OBJECTIVE

This study aims to define the incidence of infection with upper airway stimulation (UAS) devices requiring explantation in a single academic center and identify factors that may influence the risk of infection.

METHODS

A database of patients who underwent UAS at a single tertiary referral academic center from 2017 to 2021 was retrospectively reviewed to identify patients who developed surgical site infections, with and without subsequent explantation. Additional data for cases complicated by infection was extracted from the electronic medical record (EMR) and included: demographic information, medical history, complications and management, and overall outcomes. In March 2021, 2 modifications to infection control protocols were implemented: double skin preparation with Betadine and chlorhexidine, and MRSA decolonization. Statistical analysis was performed to compare infectious risk before and after these protocol changes.

RESULTS

In the study period, 215 patients underwent UAS in the specified time period and 3 cases (1.4%) of postoperative infections were identified, all of which required explantation. The infection rate did not significantly change after modifications to the surgical prep protocol (P = .52).

CONCLUSIONS

While no significant difference in infection risk was noted after modifying infection control protocols, additional longer-term study is warranted to elucidate effective infection reduction strategies.

Patient-reported experience with hypoglossal nerve stimulation in the treatment of obstructive sleep apnea

BACKGROUND

Breathing-synchronized hypoglossal nerve stimulation (HNS) is routinely used as an alternative treatment for patients with obstructive sleep apnea (OSA). Significant and clinically relevant improvements in disease severity and OSA symptoms such as daytime sleepiness as well as overall quality of life have been reported in randomized-controlled trials and large real-world cohort studies. However, so far, few data exist on patient-reported experience with the treatment.

METHODS

A structured survey with 22 questions was constructed using five-level Likert scales (1 = no agreement, 5 = complete agreement) to evaluate patient experience with HNS and perception of the treatment in the domains "Overall experience with therapy," "Experience with treatment process," and "Side-effects from treatment." Additional data were collected on current symptom status, measured with Epworth sleepiness scale (ESS) questionnaire, and OSA disease history. Multiple linear regression analysis was conducted to test associations of medical variables and response behavior. Correlations between variables and domains, as well as individual items, were assessed using Spearman rank test.

RESULTS

A total of 75 patients from Germany who were treated with breathing-synchronized HNS were enrolled (mean age 57.3 years, 78% male), and 71 questionnaires with complete data were included for analysis. Two-thirds of participants (67%) had a history of OSA history for 5 years or longer. Of all patients, 76% had normalized OSA symptoms at time of the study (ESS: 6.4 ± 5.0) and 98% reported using stimulation therapy every night. Regression analysis revealed an association of current symptoms measured with ESS and response behavior. Hence, patients with normalized daytime sleepiness reported significantly more positive experience across all domains assessed, compared to patients with residual daytime sleepiness. Overall, only 2% of participants reported side effects that made them reduce or discontinue stimulation therapy. The rate of reported side effects was associated with current symptom control under therapy.

CONCLUSIONS

Overall patient-reported experience with breathing-synchronized HNS therapy was positive and high satisfaction with the treatment process was observed. Side effects occurred, but rarely affected subjective use of the therapy or satisfaction. Subjective experience and perception are influenced by residual daytime sleepiness with stimulation therapy.

Hypoglossal Nerve Stimulation Effects on Obstructive Sleep Apnea Over Time: A Systematic Review and Meta-analysis

OBJECTIVES

This study aimed to determine the efficacy of hypoglossal nerve stimulation (HGS) in the treatment of obstructive sleep apnea.

DATA SOURCES

PubMed, Cochrane database, Embase, Web of Science, SCOPUS, and Google Scholar.

REVIEW METHODS

Five databases were reviewed to identify relevant studies that measured polysomnography parameters such as the apnea-hypopnea index (AHI) and oxygen desaturation index, as well as quality of life and functional outcomes of sleep questionnaire scores, before and after HGS.

RESULTS

In total, 44 studies involving 8670 patients met the inclusion criteria. At 12 months after treatment, approximately 47%, 72%, and 82% of patients achieved AHI values of <5, < 10, and <15, respectively. The reported clinical success rates according to Sher criteria were 80% within 12 months and 73% between 12 and 36 months. While the favorable effects exhibited a gradual reduction up to 12 months postimplantation, they generally maintained a consistent level between the 12th and 36th months, as assessed by AHI < 5, <15, and success rate according to Sher criteria.

CONCLUSION

HGS can enhance quality of life scores and polysomnography outcomes in obstructive sleep apnea patients. Although the positive effects gradually decreased until 12 months after implantation, they generally remained consistent between 12 and 36 months.

The Impact of Hypoglossal Nerve Stimulation on Secondary Health Outcomes

Objectives: Obstructive sleep apnea (OSA) is a prevalent sleep disorder that can increase the risk of hypertension, diabetes, obesity, and cardiovascular diseases. Hypoglossal nerve stimulation (HGNS) is an alternative therapy for OSA in patients who cannot tolerate continuous positive airway pressure. Understanding the impact of HGNS on blood pressure, hemoglobin A1C (A1C), and body mass index (BMI) currently remains limited. Methods: A retrospective review study of HGNS outcomes at a single practice from January 2020 to November 2022 was conducted. Inclusion/exclusion criteria were based on HGNS eligibility and postoperative titration study. Statistical analysis and data management were performed using statistical software, R (v.4.2.1; R Core Team). Paired Student's T test, Fisher's exact test, and McNemar's exact test were utilized for statistical analysis. P values less than .05 were considered statistically significant. Results: Sixty-three patients were included in this study. A significant decrease in mean apnea-hypopnea index was noted following HGNS (mean change -28; P < .0001). Similar significant decreases were also seen in mean arterial pressures (mean change -8.4, P < .0001). There was a significant change in overall antihypertensive medication requirements and in requirements ≥3 medications (P < .0005, P = .03). There was a trend toward reduction in A1C; however, there was no change in BMI or number of diabetes medications taken. Conclusions: Our results reinforce previous findings that HGNS is an effective treatment option for carefully selected patients with OSA. In addition, our findings suggest that HGNS may improve patients' quality of life while minimizing OSA associated morbidity.

Hypoglossal Nerve Stimulator in the Active Duty Population: Military Readiness and Satisfaction

INTRODUCTION

Because inadequate sleep impairs mission performance, the U.S. Army regards sleep as a core pillar of soldier readiness. There is an increasing incidence of obstructive sleep apnea (OSA) among active duty (AD) service members, which is a disqualifying condition for initial enlistment. Moreover, a new diagnosis of OSA in the AD population often prompts a medical evaluation board, and if symptomatic OSA proves refractory to treatment, this may result in medical retirement. Hypoglossal nerve stimulator implantation (HNSI) is a newer implantable treatment option, which requires minimal ancillary equipment to function and may provide a useful treatment modality to support AD service members while maintaining readiness in appropriate candidates. Because of a perception among AD service members that HNSI results in mandatory medical discharge, we aimed to evaluate the impact of HNSI on military career progression, maintenance of deployment readiness, and patient satisfaction.

METHODS

The Department of Research Programs at the Walter Reed National Military Medical Center provided institutional review board approval for this project. This is a retrospective, observational study and telephonic survey of AD HNSI recipients. Military service information, demographics, surgical data, and postoperative sleep study results were collected from each patient.Additional survey questions assessed each service member's experience with the device.

RESULTS

Fifteen AD service members who underwent HNSI between 2016 and 2021 were identified. Thirteen subjects completed the survey. The mean age was 44.8 years (range 33-61), and all were men. Six subjects (46%) were officers. All subjects maintained AD status following HNSI yielding 14.5 person-years of continued AD service with the implant. One subject underwent formal assessment for medical retention. One subject transferred from a combat role to a support role. Six subjects have since voluntarily separated from AD service following HNSI. These subjects spent an average of 360 (37-1,039) days on AD service. Seven subjects currently remain on AD and have served for an average of 441 (243-882) days. Two subjects deployed following HNSI. Two subjects felt that HSNI negatively affected their career. Ten subjects would recommend HSNI to other AD personnel. Following HNSI, of the eight subjects with postoperative sleep study data, five achieved surgical success defined as >50% reduction of apnea-hypopnea index and absolute apnea-hypopnea index value of <20.

CONCLUSIONS

Hypoglossal nerve stimulator implantation for AD service members offers an effective treatment modality for OSA, which generally allows for the ability to maintain AD status, however: The impact on deployment readiness should be seriously considered and tailored to each service member based on their unique duties before implantation. Seventy-seven percent of HNSI patients would recommend it to other AD service members suffering from OSA.

Improved levels of checkpoint molecule PD-L1 on peripheral blood monocyte subsets in obstructive sleep apnea syndrome patients upon hypoglossal nerve stimulation

Oxidative stress in patients suffering from obstructive sleep apnea syndrome (OSAS) is associated with a low-grade systemic inflammation, immune disturbance, and increased invasion of monocytes into the endothelium. Besides continuous positive airway pressure (PAP), hypoglossal nerve stimulation (HNS) has become a promising treatment option for patients with OSAS. We aimed to analyse the influence of HNS therapy on the cellular characteristics relevant for adhesion and immune regulation of circulating CD14/CD16 monocyte subsets. Whole blood flow cytometric measurements were performed to analyse the expression levels of different adhesion molecules and checkpoint molecule PD-L1 (programmed death-ligand 1) in connection with pro-inflammatory plasma cytokine IL-8 and the clinical values of BMI (body mass index), AHI (apnea-hypopnea index), ODI (oxygen desaturation index), and ESS (Epworth sleepiness scale) upon HNS treatment. Hypoglossal nerve stimulation treatment significantly improved the expression of adhesion molecule CD162 (P-selectin receptor) on non-classical monocytes and significantly downregulated the expression of PD-L1 on all three monocyte subsets. We conclude that the holistic improvement of different parameters such as the oxygenation of the peripheral blood, a reduced systemic inflammation, and the individual sleeping situation upon HNS respiratory support, leads to an improved immunologic situation.

Combination pharmacological therapy targeting multiple mechanisms of sleep apnoea: a randomised controlled cross-over trial

RATIONALE

Acetazolamide and atomoxetine-plus-oxybutynin ('AtoOxy') can improve obstructive sleep apnoea (OSA) by stabilising ventilatory control and improving dilator muscle responsiveness respectively. Given the different pathophysiological mechanisms targeted by each intervention, we tested whether AtoOxy-plus-acetazolamide would be more efficacious than AtoOxy alone.

METHODS

In a multicentre randomised crossover trial, 19 patients with moderate-to-severe OSA received AtoOxy (80/5 mg), acetazolamide (500 mg), combined AtoOxy-plus-acetazolamide or placebo at bedtime for three nights (half doses on first night) with a 4-day washout between conditions. Outcomes were assessed at baseline and night 3 of each treatment period. Mixed model analysis compared the reduction in Apnoea-Hypopnoea Index (AHI) from baseline between AtoOxy-plus-acetazolamide and AtoOxy (primary outcome). Secondary outcomes included hypoxic burden and arousal index.

RESULTS

Although AtoOxy lowered AHI by 49 (33, 62)%baseline (estimate (95% CI)) vs placebo, and acetazolamide lowered AHI by+34 (14, 50)%baseline vs placebo, AtoOxy-plus-acetazolamide was not superior to AtoOxy alone (difference: -2 (-18, 11)%baseline, primary outcome p=0.8). Likewise, the hypoxic burden was lowered with AtoOxy (+58 (37, 71)%baseline) and acetazolamide (+37 (5, 58)%baseline), but no added benefit versus AtoOxy occurred when combined (difference: -13 (-5, 39)%baseline). Arousal index was also modestly reduced with each intervention (11%baseline-16%baseline). Mechanistic analyses revealed that similar traits (ie, higher baseline compensation, lower loop gain) were associated with both AtoOxy and acetazolamide efficacy.

CONCLUSIONS

While AtoOxy halved AHI, and acetazolamide lowered AHI by a third, the combination of these leading experimental interventions provided no greater efficacy than AtoOxy alone. Failure of acetazolamide to further increase efficacy suggests overlapping physiological mechanisms.

TRIAL REGISTRATION NUMBER

NCT03892772.

Palate shape is associated with Unilateral Hypoglossal Nerve Stimulation Outcomes

OBJECTIVE

The aim was to determine the potential association between palate shape and unilateral hypoglossal nerve stimulation (HNS) outcomes.

METHODS

Preoperative drug-induced sleep endoscopy (DISE) videos were reviewed and scored by 3 blinded reviewers to determine airway narrowing at the hard-soft palate junction (HP), soft palate genu, and inferior velum, as described by Woodson (2014). Scoring was as follows: 1-open airway, 2-narrow, 3-severe narrowing. Overall palate shape (oblique, intermediate, or vertical) was determined based on prior criteria. Successful surgical treatment was defined by the HNS titration polysomnogram as a reduction of ≥50% in the apnea-hypopnea index (AHI) to <15 events/h.

RESULTS

Of 332 adults, the majority was male (77%) with an average BMI of 29.2 ± 3.6 kg/m2 . Overall success rate was 73%. Success rate was lower in patients with vertical palate shape compared with the other shapes (56% vs. 75%, p = 0.029). HP score 3 compared with scores 2 and 1 was associated with lower success rates (60% vs. 76%, p = 0.028), but genu and velum scores were not associated with outcomes. Patients with both HP score 3 and complete oropharyngeal lateral wall-related obstruction had notably worse outcomes (22% vs. 74%, p = 0.026). HP score 3 (OR 0.45, 95%CI 0.22-0.92) and vertical palate shape (OR 0.33, 95%CI 0.15-0.78) were independently associated with lower odds of surgical response after adjustment for DISE findings, age, gender, and BMI.

CONCLUSION

Vertical palate shape and narrowing at the hard-soft palate junction are independently associated with lower HNS surgical success rates.

LEVEL OF EVIDENCE

3 Laryngoscope, 134:981-986, 2024.

Clinical Characteristics of Older Adults Seeking Hypoglossal Nerve Stimulation for the Treatment of Obstructive Sleep Apnea

OBJECTIVES

Obstructive sleep apnea (OSA) is a common sleep disorder with numerous clinical correlates. Although effective treatments abound, patient acceptance and adherence is low. Hypoglossal nerve stimulation (HNS) is a surgical treatment alternative for the treatment of OSA; however, the demographic and clinical characteristics of individuals seeking HNS are not well categorized. This study sought to determine the clinical characteristics of older adults seeking HNS for the treatment of OSA.

METHODS

Self-report questionnaires were administered to all patients older than 50 years seeking a HNS consultation at a large university medical center. Questionnaires included validated National Institutes of Health Patient-Reported Outcomes Measurement Information System (NIH PROMIS) measures of physical functioning, sleep-related impairment, cognitive abilities, depression, anxiety, and anger along with the Information extracted from electronic medical records included age, sex, race, and apnea-hypopnea index (AHI).

RESULTS

Patients included 113 adults (mean age 63.30 years, 57% male, 79% white) with severe OSA (AHI = 33.91, standard deviation = 20.63). Overall, 88% of patients reported elevated insomnia symptoms, 30% reported mild difficulty with physical functioning, and 36% indicated that they had experienced moderate-severe daytime impairments attributed to poor sleep. Additionally, we found 28% of sampled individuals reported moderate-severe depressive symptomology, over 19% reported moderate-severe anxiety, and over 17% reported moderate to severe anger issues. Approximately, 38% of the sample reported moderate to severe cognitive difficulties.

CONCLUSIONS

The aim of the study was to better understand the clinical characteristics of older patients with OSA seeking HNS treatment. Utilizing NIH PROMIS questionnaires, we identified unique clinical and psychosocial correlates in this sample, which included higher rates of insomnia symptoms, physical dysfunction, cognitive deficits, and depressive symptoms than the general population. Future studies will be needed to investigate these relationships more thoroughly and throughout the course of the treatment.

Understanding Correlation of Polysomnography Parameters with Drug Induced Sleep Endoscopy in Obstructive Sleep Apnea

The aim of this study was to analyze drug-induced sleep endoscopy (DISE) findings performed in 64 patients and to evaluate the association of DISE findings with PSG parameters. This retrospective, single center, observational study included patients with obstructive sleep apnoea (OSA) who have undergone DISE as part of surgical planning. DISE was performed using dexmedetomidine infusion. The data were documented as per VOTE (velum, oropharynx, tongue base and epiglottis) classification. The patient characteristics and level 2 Polysomnography (PSG) findings were analyzed with DISE findings. Among 62 patients, mean AHI and lowest oxygen saturation levels were 39.68 ± 27.59 and 78.36 ± 9.38, respectively. Mean ESS, SSS and PSQI levels were 10.74 ±  - 4.96, 7.73 ±  - 1.52, and 8.92 +/- 4.99, respectively. A Single level of obstruction was observed in 4.8% patients, followed by 40.3%, 43.5%, and 11.3% were found to have 2, 3, and 4 levels of obstruction, respectively. All patients had palatal involvement, followed by the oropharyngeal (88.7%), the tongue base (59.7%), and the epiglottis (12.9%) obstruction. There was no significant correlation between partial collapse at velopharynx with AHI. However, complete collapse at the level of the oropharynx (p < 0.05) and the tongue base (p < 0.001) showed a statistically significant association with AHI. Also, a significant correlation was observed between the number of sites and AHI Grade (p < 0.0001). The study helps to understand the association of different patterns and degrees of anatomical obstruction in OSA with different PSG parameters. PSG and DISE findings are complimentary to each other in treatment planning and selection of surgical procedures.

Snoring Patterns During Hypoglossal Nerve Stimulation Therapy Up-Titration

Longitudinal snoring changes can be captured using a mobile phone application. During hypoglossal nerve stimulator (HNS) therapy up-titration, increasing stimulation voltage was associated with reduced snoring frequency and intensity in this case series of six patients. Laryngoscope, 134:987-992, 2024.

Revisiting the Role of Serotonin in Sleep-Disordered Breathing

Serotonin or 5-hydroxytryptamine (5-HT) is a ubiquitous neuro-modulator-transmitter that acts in the central nervous system, playing a major role in the control of breathing and other physiological functions. The midbrain, pons, and medulla regions contain several serotonergic nuclei with distinct physiological roles, including regulating the hypercapnic ventilatory response, upper airway patency, and sleep-wake states. Obesity is a major risk factor in the development of sleep-disordered breathing (SDB), such as obstructive sleep apnea (OSA), recurrent closure of the upper airway during sleep, and obesity hypoventilation syndrome (OHS), a condition characterized by daytime hypercapnia and hypoventilation during sleep. Approximately 936 million adults have OSA, and 32 million have OHS worldwide. 5-HT acts on 5-HT receptor subtypes that modulate neural control of breathing and upper airway patency. This article reviews the role of 5-HT in SDB and the current advances in 5-HT-targeted treatments for SDB.

Treatment of Residual Palatal Collapse in Hypoglossal Nerve Stimulation Using a Palatal Device

Hypoglossal nerve stimulation (HNS) has increasingly become an alternative therapy for obstructive sleep apnea patients with CPAP intolerance. Stimulation of the hypoglossal nerve during sleep enhances airway patency and alleviates collapse. Suboptimal responses to HNS often stem from insufficient palatal coupling and residual velar collapse. Combining palatal devices, such as Velumount®, with HNS represents a simple and cost-effective strategy to treat residual palatal collapse. Patients desiring conservative treatment for residual palatal obstruction under HNS may consider this combined approach. Laryngoscope, 2024.

Interfering with sleep apnea

The effects of electromagnetic interference have been hiding in plain sight for millennia and are now being applied to the non-invasive stimulation of deep tissues. In the article by Missey et al., the effect of non-invasive stimulation of the hypoglossal nerve by an interference envelope of interfering carrier waves is examined in mice and participants with sleep apnea. This stimulation is capable of activating the nerve and reducing apnea-hypopnea events. Temporally interfering electric fields have potential applications far beyond hypoglossal stimulation and may represent a revolutionary new approach to treating illness and understanding the functional organization of the nervous system.

Controversies in Sleep Apnea

This chapter discusses controversies in diagnosis and management of obstructive sleep apnea (OSA), with particular focus on surgical management to improve quality of life. Though OSA is a complex disorder that affects millions of people worldwide, its management remains controversial among clinicians. Gaps in understanding its pathophysiology, long-term health consequences, diagnostic methods, and treatment strategies exist. While continuous positive airway pressure (CPAP) therapy is considered the gold standard for moderate to severe obstructive sleep apnea (OSA), its adherence rate is often low, and its efficacy in improving outcomes beyond symptom reduction and quality of life improvement is uncertain. As such, surgical intervention may be an alternative for specific patient populations. Additionally, the type of surgical intervention may depend on individual patient needs, anatomic features, as well as preferences.

Obstructive sleep apnea diagnosis and beyond using portable monitors

Obstructive sleep apnea (OSA) is a chronic sleep and breathing disorder with significant health complications, including cardiovascular disease and neurocognitive impairments. To ensure timely treatment, there is a need for a portable, accurate and rapid method of diagnosing OSA. This review examines the use of various physiological signals used in the detection of respiratory events and evaluates their effectiveness in portable monitors (PM) relative to gold standard polysomnography. The primary objective is to explore the relationship between these physiological parameters and OSA, their application in calculating the apnea hypopnea index (AHI), the standard metric for OSA diagnosis, and the derivation of non-AHI metrics that offer additional diagnostic value. It is found that increasing the number of parameters in PMs does not necessarily improve OSA detection. Several factors can cause performance variations among different PMs, even if they extract similar signals. The review also highlights the potential of PMs to be used beyond OSA diagnosis. These devices possess parameters that can be utilized to obtain endotypic and other non-AHI metrics, enabling improved characterization of the disorder and personalized treatment strategies. Advancements in PM technology, coupled with thorough evaluation and validation of these devices, have the potential to revolutionize OSA diagnosis, personalized treatment, and ultimately improve health outcomes for patients with OSA. By identifying the key factors influencing performance and exploring the application of PMs beyond OSA diagnosis, this review aims to contribute to the ongoing development and utilization of portable, efficient, and effective diagnostic tools for OSA.

Should lateral wall collapse be a contraindication for hypoglossal nerve stimulation?

OBJECTIVE

The purpose of this study is to examine how lateral wall collapse affects treatment outcomes for hypoglossal nerve stimulation (HNS) patients.

METHODS

Patients (n = 111) queried from a single surgeon's database of HNS cases were divided into groups based on their degree of oropharyngeal lateral wall collapse noted on drug-induced sleep endoscopy (DISE): Complete, Partial, None. For each group, apnea hypopnea index (AHI) reduction, Epworth Sleepiness Scale (ESS) score, stimulation voltage, average nightly usage, need for alternate device configuration/awake sleep endoscopy, and rate of surgical success were collected. Patients with Complete collapse were compared to those with Partial/None via Student's t-tests and Pearson's Chi-square test.

RESULTS

Of the 111 eligible patients, 45 had complete, 30 partial, and 36 had no lateral oropharyngeal wall collapse. There were no statistically significant differences found between the Complete and Partial/None groups in terms of age, BMI, sex, AHI (pre and post-op), ESS (pre and post-op), voltage, alternate device configuration, or nightly adherence. Notably, a significantly greater number of the Partial/None group had surgical success (84.84 % vs 66.67 %, p = 0.024).

CONCLUSIONS

Patients with Partial/None oropharyngeal collapse were significantly more likely than patients with Complete lateral wall collapse to see surgical success. There are many factors to weigh when assessing a patient's surgical candidacy, it is clear that complete lateral wall collapse at the level of the oropharynx is a negative predictor for success in HNS.

Hypoglossal Nerve Stimulation and Cardiovascular Outcomes for Patients With Obstructive Sleep Apnea: A Randomized Clinical Trial

Importance

Sham-controlled trials are needed to characterize the effect of hypoglossal nerve stimulation (HGNS) therapy on cardiovascular end points in patients with moderate-severe obstructive sleep apnea (OSA).

Objective

To determine the effect of therapeutic levels of HGNS, compared to sham levels, on blood pressure, sympathetic activity, and vascular function.

Design, Setting, and Participants

This double-blind, sham-controlled, randomized crossover therapy trial was conducted from 2018 to 2022 at 3 separate academic medical centers. Adult patients with OSA who already had an HGNS device implanted and were adherent and clinically optimized to HGNS therapy were included. Participants who had fallen asleep while driving within 1 year prior to HGNS implantation were excluded from the trial. Data analysis was performed from January to September 2022.

Interventions

Participants underwent a 4-week period of active HGNS therapy and a 4-week period of sham HGNS therapy in a randomized order. Each 4-week period concluded with collection of 24-hour ambulatory blood pressure monitoring (ABPM), pre-ejection period (PEP), and flow-mediated dilation (FMD) values.

Main Outcomes and Measures

The change in mean 24-hour systolic blood pressure was the primary outcome, with other ABPM end points exploratory, and PEP and FMD were cosecondary end points.

Results

Participants (n = 60) were older (mean [SD] age, 67.3 [9.9] years), overweight (mean [SD] body mass index, calculated as weight in kilograms divided by height in meters squared, 28.7 [4.6]), predominantly male (38 [63%]), and had severe OSA at baseline (mean [SD] apnea-hypopnea index, 33.1 [14.9] events/h). There were no differences observed between active and sham therapy in 24-hour systolic blood pressure (mean change on active therapy, -0.18 [95% CI, -2.21 to 1.84] mm Hg), PEP (mean change on active therapy, 0.11 [95% CI, -5.43 to 5.66] milliseconds), or FMD (mean change on active therapy, -0.17% [95% CI, -1.88% to 1.54%]). Larger differences between active and sham therapy were observed in a per-protocol analysis set (n = 20) defined as experiencing at least a 50% reduction in apnea-hypopnea index between sham and active treatment.

Conclusions and Relevance

In this sham-controlled HGNS randomized clinical trial, mean 24-hour systolic blood pressure and other cardiovascular measures were not significantly different between sham and active HGNS therapy. Several methodologic lessons can be gleaned to inform future HGNS randomized clinical trials.

Trial Registration

ClinicalTrials.gov Identifier: NCT03359096.

Novel Approaches to Sleep Apnea in Heart Failure

Sleep apnea is a serious comorbid condition affecting patients with heart failure. Present in 50% to 75% of heart failure patients, it is often underrecognized, underdiagnosed, and undertreated. Patients with sleep apnea and heart failure are at increased risk of adverse cardiovascular events and sudden death. Treatment of sleep apnea has shown mixed results in reduction of adverse outcomes by sleep apnea type and intervention strategy. Evolving home-based technologies and device therapies present an exciting frontier for patients with sleep apnea and heart failure and an opportunity to improve outcomes. This article reviews novel approaches to sleep apnea in heart failure.

Hypoglossal nerve stimulation for adults with obstructive sleep apnea

ABSTRACT

Obstructive sleep apnea (OSA) is a common chronic condition in which upper airway collapse interferes with breathing during sleep, reducing sleep quality. Untreated OSA can impair a patient's health and quality of life. The recommended first-line treatment for OSA in adults is positive airway pressure, but difficulty tolerating this device limits adherence to treatment for many patients. Treatment with an implanted hypoglossal nerve stimulation (HNS) device is a relatively new second-line option for these patients, and is gaining more widespread use. Clinicians who treat OSA or provide other healthcare services to patients with HNS implants should be familiar with these devices. This article reviews HNS technology and relevant OSA pathophysiology, along with device candidacy criteria, efficacy, risks, and considerations related to use of other medical technologies for patients with HNS implants.

[Hypoglossal Stimulation: Indication, Surgical Technique and Clinical Results]

Hypoglossal stimulation is a safe and effective treatment option for patients with obstructive sleep apnea and unsuccessful PAP therapy. A number of criteria must be met for the indication: proof of failed PAP therapy and ineffectiveness of the other therapy alternatives, AHI of 15-65/h (a relevant number of central and/or mixed apneas should be excluded) and BMI up to max. 35kg/m2. In the case of the respiratory-synchronous and bilateral stimulation system, a complete concentric collapse at the velum level should currently be ruled out in DISE. In the future, stimulation of the branch of the ansa cervicalis innervating the sternothyroid muscle and the ramus internus of the superior laryngeal nerve could open up additional treatment options.

Reduced usage of upper airway stimulation therapy in patients with comorbid insomnia and obstructive sleep apnea

STUDY OBJECTIVES

Upper airway stimulation (UAS) is a hybrid surgical-medical device used to treat moderate-to-severe obstructive sleep apnea (OSA). Comorbid insomnia and OSA (COMISA) is present in ∼50% of these patients. Our aim was to study UAS outcomes and adherence in patients with COMISA.

METHODS

A retrospective review of 379 patients with OSA who underwent UAS implantation at a single institution between 2014 and 2021. Demographics, OSA severity metrics, and insomnia data were collected. Patients were categorized into OSA alone (OSAa) or COMISA. Objective adherence data were collected from device downloads during follow-up. Data were analyzed with using R Studio (R Foundation for Statistical Computing, Vienna, Austria) and Prism (Boston, MA, USA).

RESULTS

Of the 274 patients included, 148 had COMISA (54.0%) and 126 OSAa (46.0%). Average follow-up time was 2.5 years and OSAa had more males than COMISA (P < .001). Patients with COMISA had higher insomnia severity index scores than OSAa preoperatively (16 vs 8.7; P = .003). All groups showed significant decreases in objective and self-reported OSA outcomes postoperatively, but there was no difference between COMISA and OSAa. Patient with COMISA had decreased device usage (4.9 vs 5.8 h/night; P = .015) and paused therapy more often than patients with OSAa (1.4 vs 0.4 pauses/night; P < .001). Multivariate linear regression, when controlling for sex as a covariate, showed insomnia to be an independent predictor of lower UAS hours/night and more pauses/night (P < .01).

CONCLUSIONS

Patients with COMISA use UAS therapy for shorter durations and require more breaks from therapy when compared with those with OSAa. Future research is needed to explore the underlying mechanism and improve UAS treatment adherence in patients with COMISA.

CITATION

Kaffenberger TM, Chandna M, Kaki P, et al. Reduced usage of upper airway stimulation therapy in patients with comorbid insomnia and obstructive sleep apnea. J Clin Sleep Med. 2023;19(12):1997-2004.

Increased Body Mass Index Correlates with Less Favorable Postoperative Outcomes After Hypoglossal Nerve Stimulation for Obstructive Sleep Apnea: A Retrospective Cohort Study

OBJECTIVE

Obstructive sleep apnea is associated with high morbidity. Hypoglossal nerve stimulation (HNS) has become a novel (neuro-) surgical treatment strategy for obstructive sleep apnea, demonstrating good success rates. Beyond predefined inclusion and exclusion criteria, no precise data are available, enabling individual preoperative risk assessment. To improve preoperative risk stratification, this study analyzed individual patient factors that affect outcomes of HNS.

METHODS

Fourteen patients treated with unilateral HNS were analyzed retrospectively. Assessed risk factors included: hypertension, diabetes mellitus, depression, smoking, alcohol consumption, body mass index (BMI), and disease duration. Treatment success was defined as a reduction in the postoperative apnea-hypopnea index (AHI) to ≤20 events/hour, with a relative reduction of at least 50% compared to baseline.

RESULTS

A significant reduction in the postoperative apnea-hypopnea index was observed in all patients (P < 0.0001). BMI correlated significantly with postoperative AHI scores (95% confidence interval, 0.1519-0.8974; P = 0.018). Significant treatment success was observed in 50% of patients. Compared with the "Excellent Responder group," the "Responder group" demonstrated a significantly higher BMI (95% confidence interval, 1.174-6.226; P = 0.0078). Diabetes, hypertension, disease duration, smoking, depression, and alcohol consumption were not significantly associated with AHI reduction.

CONCLUSIONS

Our findings suggest that BMI may be an independent risk factor for the response to HNS, with patients who had less benefit from therapy having significantly higher BMI than "Excellent Responders." Therefore, carefully selecting patients is crucial in obtaining optimal outcomes with HNS therapy, especially those with a high BMI.

Obstructive sleep apnea in children with Down syndrome: contribution of upper airway and chemosensitivity

BACKGROUND

The high prevalence of obstructive sleep apnea syndrome (OSAS) in children with Down syndrome (DS) has been attributed to a reduced upper airway size, while the role of ventilatory control is unclear. The objectives of our case-control study were to evaluate the upper airway reduction in children with DS and moderate to severe OSAS as compared to typically developing (TD) children with similar OSAS severity and to evaluate the degree of chemical loop gain modifications including its components: controller and plant gains (CG, PG).

METHODS

Thirteen children with DS were matched for age, sex, OSAS severity and ethnicity with 26 TD children. They had undergone acoustic rhinometry and pharyngometry, chemical LG obtained during awake tidal breathing measurement and hypercapnic-hyperoxic ventilatory response testing.

RESULTS

As compared to TD, children with DS depicted reduced oropharyngeal dimensions, significantly lower CG and LG and no different PG. Their hypercapnic ventilatory response slopes were not different.

CONCLUSIONS

We concluded that the decreased CG in DS was related to decreased peripheral chemoreceptor sensitivity, and while central chemosensitivity was normal, the former explained the increased end-tidal PCO2 observed in children with DS as compared to TD. Pharyngeal dimensions are reduced in children with DS and OSAS.

IMPACT

Reduced upper airway size and nocturnal alveolar hypoventilation in children with Down syndrome (DS) have been previously reported. We confirmed that children with DS and moderate-to-severe OSA have reduced oropharyngeal size as compared to typically developing children with similar OSAS severity and demonstrated decreased peripheral chemosensitivity explaining the alveolar hypoventilation observed in children with DS. Central chemosensitivity appears to be intact in children with DS and moderate to severe OSAS Our results support growing evidence that Down syndrome is associated with autonomic nervous system dysfunction.

Minimally Invasive Hypoglossal Nerve Stimulator Enabled by ECG Sensor and WPT to Manage Obstructive Sleep Apnea

A hypoglossal nerve stimulator (HGNS) is an invasive device that is used to treat obstructive sleep apnea (OSA) through electrical stimulation. The conventional implantable HGNS device consists of a stimuli generator, a breathing sensor, and electrodes connected to the hypoglossal nerve via leads. However, this implant is bulky and causes significant trauma. In this paper, we propose a minimally invasive HGNS based on an electrocardiogram (ECG) sensor and wireless power transfer (WPT), consisting of a wearable breathing monitor and an implantable stimulator. The breathing external monitor utilizes an ECG sensor to identify abnormal breathing patterns associated with OSA with 88.68% accuracy, achieved through the utilization of a convolutional neural network (CNN) algorithm. With a skin thickness of 5 mm and a receiving coil diameter of 9 mm, the power conversion efficiency was measured as 31.8%. The implantable device, on the other hand, is composed of a front-end CMOS power management module (PMM), a binary-phase-shift-keying (BPSK)-based data demodulator, and a bipolar biphasic current stimuli generator. The PMM, with a silicon area of 0.06 mm2 (excluding PADs), demonstrated a power conversion efficiency of 77.5% when operating at a receiving frequency of 2 MHz. Furthermore, it offers three-voltage options (1.2 V, 1.8 V, and 3.1 V). Within the data receiver component, a low-power BPSK demodulator was ingeniously incorporated, consuming only 42 μW when supplied with a voltage of 0.7 V. The performance was achieved through the implementation of the self-biased phase-locked-loop (PLL) technique. The stimuli generator delivers biphasic constant currents, providing a 5 bit programmable range spanning from 0 to 2.4 mA. The functionality of the proposed ECG- and WPT-based HGNS was validated, representing a highly promising solution for the effective management of OSA, all while minimizing the trauma and space requirements.

Comparison of clinical pathways for hypoglossal nerve stimulation management: in-laboratory titration polysomnography vs home-based efficacy sleep testing

STUDY OBJECTIVES

We conducted this study to evaluate whether laboratory or home-based hypoglossal nerve stimulation (HNS) management would have equivalent objective and subjective obstructive sleep apnea outcomes 6 months after activation.

METHODS

Patients undergoing standard-of-care HNS implantation were randomly assigned in a prospective, multicenter clinical trial to either a 3-month postactivation in-laboratory titration polysomnography (tPSG) or an efficacy home sleep study (eHST) with tPSG by exception for eHST nonresponders at 5 months. Both groups underwent an eHST 6 months postactivation.

RESULTS

Sixty patients were randomly assigned. Patients experienced equivalent decreases in the apnea-hypopnea index (mean difference: -0.01 events/h [-8.75, 8.74]) across both groups with HNS; the selection of tPSG or eHST did not associate with therapy response rates (tPSG vs eHST: 63.2% vs 59.1%). The Epworth Sleepiness Scale (median of differences: 1 [-1, 3]) and device usage (median of differences: 0.0 hours [-1.3, 1.3]) outcomes were similar but did not meet a priori statistical equivalence criteria.

CONCLUSIONS

This prospective, multicenter, randomized clinical trial demonstrated that patients undergoing HNS implantation experienced statistically equivalent improvements in objective obstructive sleep apnea outcomes and similar improvements in daytime sleepiness regardless of whether they underwent tPSG. HNS titration with tPSG may not be required for all postoperative patients.

CLINICAL TRIAL REGISTRATION

Registry: ClinicalTrials.gov; Name: Inspire Home Study: Utilization of Home Monitoring During Therapy Optimization in Patients With an Inspire Upper Airway Stimulation System (Comparison of Home Sleep Testing vs. In-lab Polysomnography Testing) (HOME); URL: https://clinicaltrials.gov/ct2/show/NCT04416542; Identifier: NCT04416542.

CITATION

Kent D, Huyett P, Yu P, et al. Comparison of clinical pathways for hypoglossal nerve stimulation management: in-laboratory titration polysomnography vs home-based efficacy sleep testing. J Clin Sleep Med. 2023;19(11):1905-1912.

Research trends and hotspots regarding treatment of obstructive sleep apnea

Background

Obstructive sleep apnea (OSA) is a type of sleep-disordered breathing disease, with high prevalence and multiple complications. It seriously affects patients' quality of life and even threatens their lives. Early and effective treatment can significantly improve patients' health conditions.

Objective

In this study, the main treatment methods, research hotspots and trends of OSA were summarized through bibliometric and visualization analysis.

Methods

From the Web of Science Core Collection database, articles on the treatment of OSA from 1999 to 2022 were obtained. CiteSpace and VOSviewer were comprehensively used to visualization of journals, co-authorship of countries, institutions and authors, co-citation of references, keywords cluster and burst.

Results

A total of 2,874 publications were obtained, of which 2,584 were concerned adults and 290 about children. In adults' research, Sleep and Breathing is the most published journal (280, 10.84%), the largest number of publications come from the United States (636,24.61%) and the University of Sydney (88, 3.41%), and Pepin JL is the most published author (48, 18.58%). In children's studies, International Journal of Pediatric Otorhinolaryngology is the most published journal (41, 14.14%), the maximum number of publications were also from the United States (123, 42.41%), with the University of Pennsylvania (20, 6.90%) and Marcus CL (15, 5.17%) being the most published institutions and authors. High-frequency keywords for adults' researches include positive airway pressure, oral appliance, surgery and positional therapy. On these basis, children's studies also focus on myofunctional therapy, rapid maxillary expansion and hypoglossal nerve Stimulation.

Conclusion

Over the past two decades, research in the field of OSA therapeutics has experienced significant growth in depth and breadth. The author cooperation network has already established a solid foundation, while there is potential for further strengthening the cooperation network between countries and institutions. Currently, positive airway pressure and surgery are the primary treatments for OSA in adults and children. Future research will focus on multidisciplinary combination targeted therapy, which presents a key area of interest and challenge.

The effect of velar collapse patterns on unilateral upper airway stimulation therapy

PURPOSE

Hypoglossal nerve stimulation is a promising alternative therapy for patients with obstructive sleep apnea with continuous positive airway pressure intolerance or failure. Previous studies concluded that a velar complete concentric collapse might prohibit a good therapeutic outcome. However, certain patients have an upper velar anteroposterior collapse and a lower velar complete concentric collapse. The effect of this velar collapse pattern is unknown, preventing evidence-based decision-making for these patients. This study aimed to compare the results of upper airway stimulation therapy in these patients to patients with a pure anteroposterior velar collapse.

METHODS

A retrospective single-center cohort study was performed. Patients were included who were implanted with an upper airway stimulation device and had a 1-year follow-up.

RESULTS

Of 66 patients, 10 had an upper velar anteroposterior collapse and lower velar complete concentric collapse. Fifty-six patients had a complete or partial velar anteroposterior collapse. At follow-up, all respiratory outcomes were similarly changed between the two groups. The mean apnea and hypopnea index reduced equally (26.9 events/hour vs. 23.9 events/hour, 95% CI (-5.0, 11.0), p = 0.46). A similar decrease in the oxygen desaturation index of ≥ 4% was observed (12.0/hour versus 11.5/hour, 95% CI (-8.7, 9.7) p = 0.92) CONCLUSION: Patients with an upper velar anteroposterior collapse and a lower velar complete concentric collapse are suitable candidates for upper airway stimulation therapy. In these patients, the lower velum may represent a transition zone between the anteroposterior collapse of the upper velum and the lateral collapse of the oropharynx, instead of being a real concentric collapse.