Obstructive sleep apnea: personalizing CPAP alternative therapies to individual physiology

Introduction The recent continuous positive airway pressure (CPAP) crisis has highlighted the need for alternative obstructive sleep apnea (OSA) therapies. This article serves to review OSA pathophysiology and how sleep apnea mechanisms may be utilized to individualize alternative treatment options.Areas covered: The research highlighted below focuses on 1) mechanisms of OSA pathogenesis and 2) CPAP alternative therapies based on mechanism of disease. We reviewed PubMed from inception to July 2022 for relevant articles pertaining to OSA pathogenesis, sleep apnea surgery, as well as sleep apnea alternative therapies.Expert opinion: Although the field of individualized OSA treatment is still in its infancy, much has been learned about OSA traits and how they may be targeted based on a patient's physiology and preferences. While CPAP remains the gold-standard for OSA management, several novel alternatives are emerging. CPAP is a universal treatment approach for all severities of OSA. We believe that a personalized approach to OSA treatment beyond CPAP lies ahead. Additional research is needed with respect to implementation and combination of therapies longitudinally, but we are enthusiastic about the future of OSA treatment based on the data presented here.

Obstructive Sleep Apnea Syndrome: From Symptoms to Treatment

Obstructive sleep apnea (OSA) syndrome is a respiratory sleep disorder characterized by partial or complete recurrent episodes of upper airway collapse that occur during the night. The OSA manifests with a reduction (hypopnea) or complete cessation (apnea) of airflow in the upper airways, associated with breathing effort. OSA is a frequent and often underestimated pathology affecting between 2 and 5% of the middle-aged population. Typical nocturnal symptoms are the persistent snoring and awakenings with dyspnea sensation. On the other hand, diurnal symptoms could be sleepiness, headaches, asthenia, neurological disorders, and impaired personal relationships. Surgery of the velo-pharyngeal region had a huge evolution going from ablative techniques (UP3 and LAUP) to remodeling techniques of the pharyngeal lateral walls.

Pediatric Drug-Induced Sleep Endoscopy: Technique and Scoring System

Drug-induced sleep endoscopy (DISE) is an invaluable tool for identifying sites of obstruction for patients with obstructive sleep apnea (OSA). During DISE, the patient is in a state of drug-induced sleep, and a flexible laryngoscope is passed through the nose into the upper airway. Sites of obstruction are visualized and scored to guide surgical management. Currently, there is no universally accepted method of DISE analysis and scoring. This limitation in comparability impedes large-scale analysis between clinicians, institutions, and studies. In this report, we propose a standardized method of scoring and performing DISE in children with OSA. Our DISE scoring system is internally developed, consistent through the study, and addresses all levels of potential upper airway obstruction.

The Impact of Upper Airway Stimulation on Swallowing Function

OBJECTIVE

To evaluate the impact of upper airway stimulation therapy (UAS) on swallowing function in patients with obstructive sleep apnea.

STUDY DESIGN

Prospective cohort study.

SETTING

Academic medical center.

PARTICIPANTS AND OUTCOME MEASURES

We recorded demographic, preoperative polysomnogram (PSG), operative, and postoperative PSG data. We assessed the patients swallowing function using the Eating Assessment Tool (EAT-10) dysphagia questionnaire. This was administered both pre- and postoperatively. The postoperative EAT-10 survey was administered at least 3 months after UAS implantation.

RESULTS

During the study period, 27 patients underwent UAS implantation, completed the pre- and postoperative EAT-10 questionnaire, met inclusion/exclusion criteria, and were included in the study. The cohort consisted of 16 men and 11 women with a mean age of 63.63 years. The mean preoperative BMI, Epworth Sleepiness Scale (ESS), and Apnea Hypopnea Index (AHI) were 29.37, 10.33, and 34.90, respectively. The mean postoperative ESS and AHI were 5.25 and 7.59, respectively. These were both significantly lower than the preoperative values (P = .026 and P < .001). The mean pre- and postoperative EAT-10 scores were 0.37 and 0.22, respectively (P = .461).

CONCLUSION

Our data suggest that UAS likely does not lead to postoperative dysphagia.

Hypoglossal Nerve Stimulation and Heart Rate Variability: Analysis of STAR Trial Responders

OBJECTIVE

Hypoglossal nerve stimulation represents a novel therapy for the treatment of moderate-severe obstructive sleep apnea; nonetheless, its cardiovascular effects are not known. We examine the effects of hypoglossal nerve stimulation on heart rate variability, a measure of autonomic function.

STUDY DESIGN

Substudy of the STAR trial (Stimulation Therapy for Apnea Reduction): a multicenter prospective single-group cohort.

SETTING

Academic and private practice centers in the United States and Europe.

SUBJECTS AND METHODS

A subset of responder participants (n = 46) from the STAR trial was randomized to therapy withdrawal or therapy maintenance 12 months after surgery. Heart rate variability analysis included standard deviation of the R-R interval (SDNN), low-frequency power of the R-R interval, and high-frequency power of the R-R interval. Analysis was performed by sleep with 5-minute sliding window epochs during baseline, 12 months, and the maintenance/withdrawal period.

RESULTS

A significant improvement from baseline to 12 months in heart rate variability was seen for SDNN and low frequency across all sleep stages. SDNN analysis demonstrated no change in the wake period (mean ± SD: 0.042 ± 0.01 vs 0.077 ± 0.07, P = .19). Reduction in SDNN was correlated to improvement in apnea-hypopnea index ( r = 0.39, P = .03). In the therapy withdrawal group, no significant changes in SDNN were seen for N1/N2, N3, or rapid eye movement sleep.

CONCLUSION

Hypoglossal nerve stimulation therapy appears to reduce heart rate variability during sleep. This reduction was not affected by a 1-week withdrawal period. Larger prospective studies are required to better understand the effect of hypoglossal nerve stimulation on autonomic dysfunction in obstructive sleep apnea.

Continuous positive airway pressure therapy in obstuctive sleep apnea: benefits and alternatives

INTRODUCTION

Obstructive sleep apnea (OSA) is a highly prevalent condition affecting persons of all age with an increasing public health burden. It is implicated in cardiovascular disease, metabolic syndrome, neurocognitive impairment, reductions in quality of life, and increased motor vehicle accidents. The goals of OSA treatment are to improve sleep and daytime symptoms, and minimize cardiovascular risks.Areas covered: Continuous positive airway pressure (CPAP) is considered the gold standard therapy that delivers pressurized air into the upper airway to relieve obstruction during sleep. Although CPAP is an effective modality of treatment for OSA, adherence to therapy is highly variable. This article highlights the benefits of CPAP therapy, along with alternative treatment options including oral appliance, implantable and wearable devices, and surgery. Expert commentary: CPAP therapy is the gold standard treatment option and should continue to be offered to those who suffer from OSA. Alternative options are available for those who are unable to adhere to CPAP or choose an alternative treatment modality. The most interesting advances have been incorporating orthodontic procedures in conjunction with myofunctional therapy in prepubertal children, raising the possibility of OSA prevention by initiating treatment early in life.

A Cost-Effectiveness Analysis of Surgery for Middle-Aged Men with Severe Obstructive Sleep Apnea Intolerant of CPAP

STUDY OBJECTIVES

Obstructive sleep apnea (OSA) is associated with increased cardiovascular morbidity and mortality. Conventional OSA therapy necessitates indefinite continuous positive airway pressure (CPAP). Although CPAP is an effective treatment modality, up to 50% of OSA patients are intolerant of CPAP. We explore whether surgical modalities developed for those intolerant of CPAP are cost-effective.

METHODS

We construct a lifetime semi-Markov model of OSA that accounts for observed increased risks of stroke, cardiovascular disease, and motor vehicle collisions for a 50-year-old male with untreated severe OSA. Using this model, we compare the cost-effectiveness of (1) no treatment, (2) CPAP only, and (3) CPAP followed by surgery (either palatopharyngeal reconstructive surgery [PPRS] or multilevel surgery [MLS]) for those intolerant to CPAP.

RESULTS

Compared with the CPAP only strategy, CPAP followed by PPRS (CPAP-PPRS) adds 0.265 quality adjusted life years (QALYs) for an increase of $2,767 (discounted 2010 dollars) and is highly cost effective with an incremental cost-effectiveness ratio (ICER) of $10,421/QALY for a 50-year-old male with severe OSA. Compared to a CPAP-PPRS strategy, the CPAP-MLS strategy adds 0.07 QALYs at an increase of $6,213 for an ICER of $84,199/QALY. The CPAP-PPRS strategy appears cost-effective over a wide range of parameter estimates.

CONCLUSIONS

Palatopharyngeal reconstructive surgery appears cost-effective in middle-aged men with severe OSA intolerant of CPAP. Further research is warranted to better define surgical candidacy as well as short-term and long-term surgical outcomes.

COMMENTARY

A commentary on this article appears in this issue on page 509.

Transoral robotic surgery for treatment of obstructive sleep apnea: factors predicting surgical response

OBJECTIVES/HYPOTHESIS

We reviewed our experience with the use of transoral robotic surgery (TORS) for base of tongue (BOT) reduction either alone or as part of multilevel strategy in the treatment of obstructive sleep apnea/hypopnea syndrome (OSAHS) in order to identify clinical characteristics that may be associated with surgical response.

STUDY DESIGN

Case series.

METHODS

Between June 2010 and May 2014, BOT reduction via TORS ± partial epiglottectomy ± uvulopalatopharyngoplasty were performed on 72 patients with OSAHS. Thirty-nine patients (15 females and 24 males) with complete preoperative and postoperative clinical information including polysomnograms were included in this study.

RESULTS

Mean apnea-hypopnea index (AHI) was 43.9 ± 32.3 preoperatively and 21.9 ± 23.5 postoperatively and reflected a statistically significant (P < 0.001) AHI reduction of 50.9% ± 38.1%. Statistical significant reduction in daytime somnolence, as measured by Epworth Sleepiness Scale (15.6 ± 5.4 preoperatively vs. 5.7 ± 4.3 postoperatively; P < 0.001), was also achieved. No statistical significant difference was found between preoperative and postoperative body mass index (BMI) (32.9 ± 7.0 vs. 32.4 ± 7.3; P = 0.270). Surgical response, as defined by > 50% reduction in AHI and final AHI < 15 with resolution of daytime somnolence, was achieved in 21 patients (53.8%). Clinical characteristics found to be significantly different between the responders and nonresponders were BMI, AHI, and lateral velopharyngeal collapse. Patients with BMI < 30, AHI < 60, or absence of lateral velopharyngeal collapse have excellent surgical response rate of 88.2%, 67.9%, or 66.7%, respectively.

CONCLUSIONS

We identified three clinical characteristics associated with increased surgical response rate. This finding may be useful for patient selection and counseling prior to surgery.