Effectiveness of sleep surgery versus a mandibular advancement device for obstructive sleep apnea in terms of nocturnal cardiac autonomic activity

Allergic rhinitis may attenuate the sympathovagal imbalances in patients with severe obstructive sleep apnea: pilot study using a heart rate variability analysis

PURPOSE

The effect of allergic rhinitis (AR) on autonomic nervous system in patients with obstructive sleep apnea (OSA) remains unclear. We utilized heart rate variability (HRV) analysis to assess cardiac autonomic activity in patients with OSA, comparing those with and without allergic rhinitis (AR).

METHODS

We enrolled 182 patients who visited our sleep clinic complaining of habitual snoring or apnea during sleep. All patients underwent full-night polysomnography (PSG) and multiple allergen simultaneous tests. We calculated the HRV extracted from the electrocardiography of the PSG. Participants were divided into a normal group and an AR group, and HRV indices were compared according to OSA severity in each group.

RESULTS

The low-frequency (LF) to high-frequency (HF) ratio (LF/HF; r = 0.336, p < 0.001), LF normalised unit (LFnu; r = 0.345, p < 0.001), and HFnu (r = -0.345, p < 0.001) were significantly correlated with the apnea-hypopnea index. The HRV index comparison between non-severe and severe OSA in the normal group showed significant differences in LFnu (64.7 ± 12.5 in non-severe and 72.4 ± 11.7 in severe, p < 0.001), LF/HF (2.3 ± 1.6 in non-severe and 3.3 ± 2.0 in severe, p = 0.002), and HFnu (35.3 ± 12.5 in non-severe and 27.6 ± 11.7 in severe, p < 0.001). However, in the AR group, LFnu (p = 0.648), LF/HF (p = 0.441), and HFnu (p = 0.648) were comparable between non-severe and severe OSA.

CONCLUSION

Considering that LFnu, HFnu, and LF/HF represent sympathetic activity, parasympathetic activity, and sympathovagal balance, respectively, AR may attenuate the sympathetic predominance and sympathovagal imbalance associated with cardiovascular morbidity in severe OSA.

Mandibular Advancement Devices in Obstructive Sleep Apnea and Its Effects on the Cardiovascular System: A Comprehensive Literature Review

BACKGROUND

Obstructive sleep apnea syndrome (OSA) is a chronic inflammatory disease characterized by endothelial dysfunction and cardiovascular complications. Continuous positive airway pressure (CPAP) is the standard treatment, hence poor adherence has prompted interest in mandibular advancement devices (MAD) as an alternative. This comprehensive review aimed to explore the effects of MAD therapy on oxidative stress, inflammation, endothelial function, and its impact on the cardiovascular risk in OSA patients.

RESULTS

MAD therapy significantly reduces the apnea-hypopnea index (AHI), improves serum nitric oxide (NOx) concentrations, reduces oxidative stress markers, and enhances endothelial function. Animal studies indicated that MAD reduces myocardial fibrosis and attenuates inflammatory markers. While both CPAP and MADs improve endothelial function and heart rate variability, CPAP is more effective in reducing OSA severity. Nevertheless, MAD has higher compliance, contributing to its positive impact on cardiovascular function. Moreover, CPAP and MADs have similar effectiveness in reducing cardiovascular risk.

CONCLUSIONS

MAD therapy is an effective alternative to CPAP, particularly for patients with mild to moderate OSA as well as those intolerant to CPAP. It offers significant improvements in endothelial function and oxidative stress. Further studies are needed to assess MAD therapy in comprehensive OSA management.

Consensus Statements among European Sleep Surgery Experts on Snoring and Obstructive Sleep Apnea: Part 2 Decision-Making in Surgical Management and Peri-Operative Considerations

Background: Reaching consensus on decision-making in surgical management and peri-operative considerations regarding snoring and obstructive sleep apnea (OSA) among sleep surgeons is critical in the management of patients with such conditions, where there is a large degree of variability. Methods: A set of statements was developed based on the literature and circulated among eight panel members of European experts, utilizing the Delphi method. Responses were provided as agree and disagree on each statement, and the comments were used to assess the level of consensus and develop a revised version. The new version, with the level of consensus and anonymized comments, was sent to each panel member as the second round. This was repeated for a total of five rounds. Results: The final set included a total of 71 statements: 29 stand-alone and 11 with 42 sub-statements. On the 33 statements regarding decision-making in surgical management, there was 60.6%, 27.3%, and 6.1% consensus among all eight, seven, and six panelists, respectively. On the 38 statements regarding the peri-operative considerations, there was 55.3%, 18.4%, and 15.8% consensus among all eight, seven, and six panelists, respectively. Conclusions: These results indicate the need for an expanded review of the literature and discussion to enhance consensus among the sleep surgeons that consider surgical management in patients with snoring and OSA.

Obstructive sleep apnea heterogeneity and autonomic function: a role for heart rate variability in therapy selection and efficacy monitoring

Obstructive sleep apnea is a highly prevalent sleep-related breathing disorder, resulting in a disturbed breathing pattern, changes in blood gases, abnormal autonomic regulation, metabolic fluctuation, poor neurocognitive performance, and increased cardiovascular risk. With broad inter-individual differences recognised in risk factors, clinical symptoms, gene expression, physiological characteristics, and health outcomes, various obstructive sleep apnea subtypes have been identified. Therapeutic efficacy and its impact on outcomes, particularly for cardiovascular consequences, may also vary depending on these features in obstructive sleep apnea. A number of interventions such as positive airway pressure therapies, oral appliance, surgical treatment, and pharmaceutical options are available in clinical practice. Selecting an effective obstructive sleep apnea treatment and therapy is a challenging medical decision due to obstructive sleep apnea heterogeneity and numerous treatment modalities. Thus, an objective marker for clinical evaluation is warranted to estimate the treatment response in patients with obstructive sleep apnea. Currently, while the Apnea-Hypopnea Index is used for severity assessment of obstructive sleep apnea and still considered a major guide to diagnosis and managements of obstructive sleep apnea, the Apnea-Hypopnea Index is not a robust marker of symptoms, function, or outcome improvement. Abnormal cardiac autonomic modulation can provide additional insight to better understand obstructive sleep apnea phenotyping. Heart rate variability is a reliable neurocardiac tool to assess altered autonomic function and can also provide cardiovascular information in obstructive sleep apnea. Beyond the Apnea-Hypopnea Index, this review aims to discuss the role of heart rate variability as an indicator and predictor of therapeutic efficacy to different modalities in order to optimise tailored treatment for obstructive sleep apnea.

The 24-Hour Cardiac Autonomic Activity in Patients With Allergic Rhinitis

BACKGROUND

Definitive knowledge of the 24-hour cardiac autonomic activity in patients with allergic rhinitis (AR) is lacking. Thus, we aimed to evaluate heart rate variability (HRV), which is used to measure cardiac autonomic activity by 24-hour Holter monitoring in patients with AR.

METHODS

We enrolled 32 patients who visited our clinic and were diagnosed with AR. The control group was selected four-fold (n = 128) by matching (age, sex, hypertension, and diabetes) in the AR group from a Holter registry in the cardiology department. The HRV results, which were measured using 24-hour Holter monitoring, were compared between the AR and control groups.

RESULTS

All time-domain parameters of HRV revealed no differences between the groups. However, among the frequency domain parameters of HRV, the low-frequency to high-frequency ratio and low-frequency power in normalized units were significantly lower in the AR group. Conversely, high-frequency power in normalized units was significantly higher in the AR group. In the multiple regression analysis, AR was independently associated with sympathetic withdrawal (adjusted odds ratio = 3.393, P = 0.020) after adjusting for age, sex, hypertension, diabetes mellitus, and hyperlipidemia.

CONCLUSIONS

The present findings suggest differences in cardiac autonomic activity which are related with sympathetic withdrawal in patients with AR compared with that in the normal population over 24 hours.

Evaluation of mandibular advancement device placement based on levels of TNF-alpha in participants with obstructive sleep apnea: A clinical study

STATEMENT OF PROBLEM

Objective assessments of the effect of mandibular advancement device on patients with obstructive sleep apnea are lacking.

PURPOSE

The purpose of this clinical study was to compare levels of serum tumor necrosis factor alpha (TNF-alpha), Epworth Sleepiness Scale score, and Berlin Questionnaire score in patients with mild to moderate obstructive sleep apnea before and after treatment with a mandibular advancement device.

MATERIAL AND METHODS

Twenty participants diagnosed with mild to moderate obstructive sleep apnea based on polysomnography testing were enrolled. A custom nonadjustable mandibular advancement device with 70% mandibular protrusion was provided for each participant for management of the obstructive sleep apnea. Evaluation of TNF-alpha levels was performed before treatment (baseline) and 3 and 6 months after starting mandibular advancement device therapy by using a Human TNF-alpha enzyme-linked immunoassay (ELISA) sandwich kit. The Epworth Sleepiness Scale and Berlin Questionnaire were also filled out by the participants at the same time intervals (α=.05).

RESULTS

A statistically significant decline in the levels of TNF-alpha was observed at 3 and 6 months compared with baseline (P<.001). The Epworth Sleepiness Scale scores showed a statistically significant reduction at 3 and 6 months compared with baseline (P<.001). The risk of obstructive sleep apnea assessed by using the Berlin Questionnaire was found to be significantly reduced at 6 months compared with baseline (P=.001).

CONCLUSIONS

Patients with mild to moderate obstructive sleep apnea showed reduced levels of TNF-alpha and Epworth Sleepiness Scale and Berlin Questionnaire scores when treated with a mandibular advancement device.

A Classifying Model of Obstructive Sleep Apnea Based on Heart Rate Variability in a Large Korean Population

BACKGROUND

The majority of patients with obstructive sleep apnea do not receive timely diagnosis and treatment because of the complexity of a diagnostic test. We aimed to predict obstructive sleep apnea based on heart rate variability, body mass index, and demographic characteristics in a large Korean population.

METHODS

Models of binary classification for predicting obstructive sleep apnea severity were constructed using 14 features including 11 heart rate variability variables, age, sex, and body mass index. Binary classification was conducted separately using apnea-hypopnea index thresholds of 5, 15, and 30. Sixty percent of the participants were randomly allocated to training and validation sets while the other forty percent were designated as the test set. Classifying models were developed and validated with 10-fold cross-validation using logistic regression, random forest, support vector machine, and multilayer perceptron algorithms.

RESULTS

A total of 792 (651 men and 141 women) subjects were included. The mean age, body mass index, and apnea-hypopnea index score were 55.1 years, 25.9 kg/m², and 22.9, respectively. The sensitivity of the best performing algorithm was 73.6%, 70.7%, and 78.4% when the apnea-hypopnea index threshold criterion was 5, 10, and 15, respectively. The prediction performances of the best classifiers at apnea-hypopnea indices of 5, 15, and 30 were as follows: accuracy, 72.2%, 70.0%, and 70.3%; specificity, 64.6%, 69.2%, and 67.9%; area under the receiver operating characteristic curve, 77.2%, 73.5%, and 80.1%, respectively. Overall, the logistic regression model using the apnea-hypopnea index criterion of 30 showed the best classifying performance among all models.

CONCLUSION

Obstructive sleep apnea was fairly predicted by using heart rate variability, body mass index, and demographic characteristics in a large Korean population. Prescreening and continuous treatment monitoring of obstructive sleep apnea may be possible simply by measuring heart rate variability.

The differences between daytime and night-time heart rate variability may usefully predict the apnea-hypopnea index in patients with obstructive sleep apnea

STUDY OBJECTIVES

The association between daytime/night-time heart rate variability (HRV) and the apnea-hypopnea index (AHI) remains unclear. We sought a relationship between AHI and the daytime-to night-time HRV ratio as measured by 24-h Holter monitoring in patients with obstructive sleep apnea (OSA).

METHODS

We prospectively enrolled 66 patients who visited our sleep clinic complaining of habitual snoring or sleep apnea. All underwent 24-h Holter monitoring (to measure HRV) combined with full-night polysomnography (PSG). Sixty-two met our enrolment criteria. We evaluated the associations between HRV frequency domains and the PSG indices. We also considered medical histories and anthropometric data.

RESULTS

The night-time very low frequency (VLF), low frequency (LF), and high frequency (HF) HRVs were significantly higher than the daytime values. On correlation analysis, the day/night VLF (r = 0.550, p < 0.001), LF (r = 0.556, p < 0.001), and HF (r = 0.303, p = 0.017) HRVs were significantly related to the AHI. Of the day/night HRV ratios, the VLF (p for trend = 0.003) and LF (p for trend = 0.013) ratios decreased significantly by OSA severity. Multivariable analysis showed that the day/night VLF (β = 16.387, p < 0.001) and day/night LF (β = 25.248, p < 0.001) were independently (and significantly) associated with the AHI.

CONCLUSIONS

Twenty-four-hour Holter monitoring may usefully predict AHI. The day/night VLF and day/night LF ratios tended to decrease by OSA severity and were independently associated with the AHI.