Nocturnal hypoxia and age-related macular degeneration.

BACKGROUND: Nocturnal hypoxia is common, under-diagnosed and is found in the same demographic at risk of age-related macular degeneration (AMD). The objective of this study was to determine any association between nocturnal hypoxia and AMD, its severity, and the high-risk sub-phenotype of reticular pseudodrusen (RPD). METHODS: This cross-sectional study included participants aged ≥50 years with AMD, or normal controls, exclusive of those on treatment for obstructive sleep apnoea. All participants had at home, overnight (up to 3 nights) pulse oximetry recordings and multimodal imaging to classify AMD. Classification of Obstructive Sleep Apnea (OSA) was determined based on oxygen desaturation index [ODI] with mild having values of 5-15 and moderate-to-severe >15. RESULTS: A total of 225 participants were included with 76% having AMD, of which 42% had coexistent RPD. Of the AMD participants, 53% had early/intermediate AMD, 30% had geographic atrophy (GA) and 17% had neovascular AMD (nAMD). Overall, mild or moderate-to-severe OSAwas not associated with an increased odds of having AMD nor AMD with RPD (p ≥ 0.180). However, moderate-to-severe OSA was associated with increased odds of having nAMD (odds ratio = 6.35; 95% confidence interval = 1.18 to 34.28; p = 0.032), but not early/intermediate AMD or GA, compared to controls (p ≥ 0.130). Mild OSA was not associated with differences in odds of having AMD of any severity (p ≥ 0.277). CONCLUSIONS: There was an association between nocturnal hypoxia as measured by the ODI and nAMD. Hence, nocturnal hypoxia may be an under-appreciated important modifiable risk factor for nAMD.

Profile of Patients With Obstructive Sleep Apnea: An Initial Experience in a Tertiary Health Facility.

Introduction Obstructive sleep apnea (OSA) is the most common sleep-related breathing disorder with increasing prevalence worldwide. The disease is, however, underdiagnosed in many resource-limited countries, especially in sub-Saharan Africa with unknown prevalence. Study aim The aim of this study was to determine the demographic and clinical characteristics, as well as measured sleep study parameters of suspected OSA patients. Methods The study was a retrospective review of the clinical characteristics and home sleep study reports of patients seen at the respiratory and sleep clinic from January 2020 to June 2022. Descriptive statistics such as means, medians, and percentages were employed to summarize the data using tables and graphs. Spearman correlation coefficient and Fisher's exact test were used to determine associations between the variables. Findings The study participants were predominantly male, and 64.7% were ≥50 years of age. Approximately 76% of the cases had moderate-to-severe OSA based on the apnea-hypopnea index (AHI) scores with a mean BMI of 38.4kg/m2 and 43.1kg/m2, respectively (p=0.013), and a mean STOP-BANG score of 5.2 and 6.2, respectively (p <0.001). There was a positive correlation between AHI scores and BMI of the patients (r=0.252, p=0.003), as well as with their STOP-BANG scores (r=0.436, p< 0.001). Oxygen desaturation index (ODI) parameters of participants also positively correlated with the AHI scores (r=0.872, p<0.001). Conclusion The proportion of patients with moderate-to-severe OSA was high. Obesity was significantly associated with AHI scores, which also positively correlated with the STOP-BANG and ODI scores. These results suggest that the burden of OSA, which is closely linked with obesity, could be underestimated in Ghana and requires epidemiological studies in the very near future to clearly define and anticipate its impact on the health economy of Ghana.

Exercise-Induced Oxygen Desaturation Increases Arterial Stiffness in Patients with COPD During the 6WMT.

Objective: Given the established impact of exercise in reducing arterial stiffness and the potential for intermittent hypoxia to induce its elevation, this study aims to understand how oxygen desaturation during exercise affects arterial stiffness in individuals with COPD. Methods: We enrolled patients with stable COPD from China-Japan Friendship Hospital from November 2022 to June 2023. The 6-minute walk test (6-MWT) was performed with continuous blood oxygen saturation (SpO2) monitoring in these patients. The patients were classified into three groups: non-exercise induced desaturation (EID), mild-EID and severe-EID, according to the changes in SpO2 during the 6-MWT. The Cardio-Ankle Vascular Index (CAVI) and the change in CAVI (ΔCAVI, calculated as CAVI before 6MWT minus CAVI after the 6MWT) were measured before and immediately after the 6MWT to assess the acute effects of exercise on arterial stiffness. GOLD Stage, pulmonary function, and other functional outcomes were also measured in this study. Results: A total of 37 patients with stable COPD underwent evaluation for changes in CAVI (ΔCAVI) before and after the 6-MWT. Stratification based on revealed three subgroups: non-EID (n=12), mild-EID (n=15), and severe-EID (n=10). The ΔCAVI values was -0.53 (-0.95 to -0.31) in non-EID group, -0.20 (-1.45 to 0.50) in mild-EID group, 0.6 (0.08 to 0.73) in severe-EID group. Parametric tests indicated significant differences in ΔCAVI among EID groups (p = 0.005). Pairwise comparisons demonstrated significant distinctions between mild-EID and severe-EID groups, as well as between non-EID and severe-EID groups (p = 0.048 and p = 0.003, respectively). Multivariable analysis, adjusting for age, sex, GOLD stage, diffusion capacity, and blood pressure, identified severe-EID as an independent factor associated with ΔCAVI (B = 1.118, p = 0.038). Conclusion: Patients with COPD and severe-EID may experience worsening arterial stiffness even during short periods of exercise.

Ambient ultrafine particles exacerbate oxygen desaturation during sleep in patients with chronic obstructive pulmonary disease: New insights into the effect spectrum of ultrafine particles on susceptible populations.

The health effects of ultrafine particles (UFPs) are of growing global concern, but the epidemiological evidence remains limited. Sleep-disordered breathing (SDB) characterized by hypoxemia is a prevalent condition linked to many debilitating chronic diseases. However, the role of UFPs in the development of SDB is lacking. Therefore, this prospective panel study was performed to specifically investigate the association of short-term exposure to UFPs with SDB parameters in patients with chronic obstructive pulmonary disease (COPD). Ninety-one COPD patients completed 226 clinical visits in Beijing, China. Personal exposure to ambient UFPs of 0-7 days was estimated based on infiltration factor and time-activity pattern. Real-time monitoring of sleep oxygen saturation, spirometry, respiratory questionnaires and airway inflammation detection were performed at each clinical visit. Generalized estimating equation was used to estimate the effects of UFPs. Exposure to UFPs was significantly associated with increased oxygen desaturation index (ODI) and percent of the time with oxygen saturation below 90 % (T90), with estimates of 21.50 % (95%CI: 6.38 %, 38.76 %) and 18.75 % (95%CI: 2.83 %, 37.14 %), respectively, per 3442 particles/cm3 increment of UFPs at lag 0-3 h. Particularly, UFPs' exposure within 0-7 days was positively associated with the concentration of alveolar nitric oxide (CaNO), and alveolar eosinophilic inflammation measured by CaNO exceeding 5 ppb was associated with 29.63 % and 33.48 % increases in ODI and T90, respectively. In addition, amplified effects on oxygen desaturation were observed in current smokers. Notably, individuals with better lung function and activity tolerance were more affected by ambient UFPs due to longer time spent outdoors. To our knowledge, this is the first study to link UFPs to hypoxemia during sleep and uncover the key role of alveolar eosinophilic inflammation. Our findings provide new insights into the effect spectrum of UFPs and potential environmental and behavioral intervention strategies to protect susceptible populations.

The 1-minute sit-to-stand test as a screening tool to assess exercise-induced oxygen desaturation in normoxemic people with interstitial lung disease.

BACKGROUND: In patients with interstitial lung disease (ILD), exercise-induced desaturation during the six-minute walk test (6MWT), specifically nadir oxygen saturation (nSpO2) of ≤88% is a negative prognostic marker. As the 6MWT is often impractical for ILD patients, the aim of this study is to compare the 1-minute sit-to-stand test (1minSTS) with the 6MWT to detect exercise-induced desaturation. METHODS: Participants were recruited from a tertiary referral clinic with both tests performed on the same day. Utilising Bland-Altman analysis, the relationship between nSpO2 on 1minSTS and 6MWT was determined. An area under the receiver operating characteristic curve (AUC) determined the ability of nSpO2 on 1minSTS test to predict SpO2 ≤88% on 6MWT. RESULTS: Fifty participants completed the study (idiopathic pulmonary fibrosis n=24,48%; connective tissue disease associated ILD n=20,40%; other ILD n=6,12%). Mean (SD) FVC%pred was 73±16%, mean DLCO%pred 57±16% and resting SpO2 99±1%. The 1minSTS resulted in less exercise-induced oxygen desaturation, with a median IQR nSpO2 of 95% (89-98) and 93% (85-96) respectively (p<0.001). Moderate agreement was determined between the nSpO2 on both tests, with a mean difference of 3.2% [-14 to +3.0%]. The 1minSTS test accurately identified participants with nSpO2 ≤88% on 6MWT (AUC 0.96). Oxygen desaturation ≤ 94% during the 1minSTS test provided 100% sensitivity and 87% specificity for oxygen desaturation ≤88% at 6MWT. CONCLUSION: This study demonstrates that exercise-induced oxygen desaturation during the 1minSTS test correlates with oxygen desaturation on 6MWT. The 1minSTS may be a practical screening tool for ILD patients who would benefit from further exercise testing.

Evaluation of novel indices of walking performance taking oxygen desaturation into account during six-minute walk test in cardiovascular disease patients.

In pulmonary disease patients since oxygen desaturation during 6-min walk test (6MWT) affects walk distance (6MWD), some novel indices such as desaturation/distance ratio [DDR, oxygen desaturation area (DAO2)/6MWD] and distance-saturation product [DSP, 6MWD × minimum peripheral oxygen saturation (SpO2)] are evaluated. However, there has been no study examining these indices that consider exercise-induced desaturation (EID) in patients with cardiovascular disease. In 94 cardiovascular disease patients without pulmonary complications, 6MWT and echocardiography were performed at the entry of cardiac rehabilitation. SpO2 was measured during 6MWT using a continuously monitorable pulse oximeter, and DSP and DDR were calculated using minimum SpO2 and DAO2 [sum of (100-SpO2) per second during 6MWT], respectively. EID was defined as SpO2 decrease of ≥ 4% or minimum SpO2 of < 90% during 6MWT. DSP was slightly lower and DDR was markedly higher in patients with EID than in those without. When examining correlations of DSP and DDR with their components, DSP was correlated with 6MWD much closely than minimum SpO2, while DDR was correlated as closely with DAO2 as 6MWD. Furthermore, DAO2, but not minimum SpO2, had a direct correlation with 6MWD. As for associations with cardiac function, DSP was correlated with several cardiac parameters, but DDR was not correlated with any of these parameters. Our findings suggest that oxygen desaturation during 6MWT affects walking distance in cardiovascular disease patients even without pulmonary complications and that DDR is more appropriate than DSP as an index of walking performance that takes EID into consideration, independently of cardiac function.

Impact of Intermittent Hypoxia Related to Obstructive Sleep Apnoea Syndrome on Low-Grade Inflammation in Hypertensive Patients: Potential Implications for Cardiovascular Risk.

There is evidence for a particular relationship between low-grade inflammation (LGI) and intermittent hypoxia (IH) related to obstructive sleep apnoea syndrome (OSAS). However, despite the potential deleterious cardiovascular consequences associated with this LGI in hypertensive patients, few studies have investigated the impact of IH related to OSAS on CRP levels in this subpopulation. In total, 1404 hypertensive patients were selected retrospectively from the Sleep Laboratory database. CRP levels ≥3 mg/L but <10 mg/L were used as cut-offs to identify hypertensive patients with LGI. Logistic regressions were conducted to examine the risk of LGI associated with IH related to OSAS in hypertensive patients. LGI was frequent (33.8%) in hypertensive patients. After adjustment for confounders, multivariate logistic regressions revealed that only moderate to severe OSAS (apnoea-hypopnoea index ≥ 15/h) with high IH (oxygen desaturation index ≥ 15/h) [OR 1.51 (95% CI 1.06-2.14)] was significantly associated with LGI in hypertensive patients (p-value = 0.045). Consistent with our hypothesis, our results demonstrated the existence of a particular subtype of hypertensive patients at high cardiovascular risk characterised by the presence of LGI induced by IH hypoxia related to moderate to severe OSAS, which justifies the establishment of adequate management of this pathology to allow better cardiovascular prevention in this subpopulation.

Relationship between obstructive sleep apnea and pulmonary hypertension: past, present and future.

INTRODUCTION: Obstructive sleep apnea (OSA) is a widely prevalent condition with consequent multiple organ systems complications. There is consensus that OSA is associated with negative effects on pulmonary hemodynamics but whether it contributes to development of clinical pulmonary hypertension (PH) is unclear. AREAS COVERED: In this review, we (1) highlight previous studies looking into the possible bidirectional association of OSA and PH, focusing on those that explore clinical prognostic implications, (2) explore potential pathophysiology, (3) discuss the new metrics in OSA, (4) describe endo-phenotyping of OSA, (5) recommend possible risk assessment and screening pathways. EXPERT OPINION: Relying only on symptoms to consider a sleep study in PH patients is a missed opportunity to detect OSA, which, if present and not treated, can worsen outcomes. The potential prognostic role of sleep study metrics such as oxygen desaturation index (ODI), hypoxic burden (HB) and ventilatory burden (VB) in OSA should be studied in prospective trials to identify patients at risk for PH. AHI alone has not provided clarity. In those with PH, we should consider replacing ambulatory overnight pulse oximetry (OPO) with home sleep studies (HST). In PH patients, mild OSA should be sufficient to consider PAP therapy.

Significance of preoperative exercise oxygen desaturation in lung cancer with interstitial lung disease.

OBJECTIVES: Evaluating the diffusing capacity for carbon monoxide (DLco) is crucial for patients with lung cancer and interstitial lung disease. However, the clinical significance of assessing exercise oxygen desaturation (EOD) remains unclear. METHODS: We retrospectively analysed 186 consecutive patients with interstitial lung disease who underwent lobectomy for non-small-cell lung cancer. EOD was assessed using the two-flight test (TFT), with TFT positivity defined as ≥5% SpO2 reduction. We investigated the impact of EOD and predicted postoperative (ppo)%DLco on postoperative complications and prognosis. RESULTS: A total of 106 (57%) patients were identified as TFT-positive, and 58 (31%) patients had ppo% DLco < 30%. Pulmonary complications were significantly more prevalent in TFT-positive patients than in TFT-negative patients (52% vs 19%, P < 0.001), and multivariable analysis revealed that TFT-positivity was an independent risk factor (odds ratio 3.46, 95% confidence interval 1.70-7.07, P < 0.001), whereas ppo%DLco was not (P = 0.09). In terms of long-term outcomes, both TFT positivity and ppo%DLco < 30% independently predicted overall survival. We divided the patients into 4 groups based on TFT positivity and ppo%DLco status. TFT-positive patients with ppo%DLco < 30% exhibited the significantly lowest 5-year overall survival among the 4 groups: ppo%DLco ≥ 30% and TFT-negative, 54.2%; ppo%DLco < 30% and TFT-negative, 68.8%; ppo%DLco ≥ 30% and TFT-positive, 38.1%; and ppo%DLco < 30% and TFT-positive, 16.7% (P = 0.001). CONCLUSIONS: Incorporating EOD evaluation was useful for predicting postoperative complications and survival outcomes in patients with lung cancer and interstitial lung disease.

Childhood maltreatment and sleep apnea: Findings from a cross-sectional general population study.

OBJECTIVE: Cumulative evidence indicates that childhood maltreatment (CM) is associated with sleep disturbances possibly suggesting sleep apnea. However, the relation between CM and objective measures of sleep apnea as determined by polysomnography (PSG) has not yet been assessed. METHODS: Using a cross-sectional design and based on PSG measurements from N = 962 subjects from the SHIP-Trend general population study, we used linear regression models to investigate the relationship between apnea-hypopnea (AHI) and oxygen desaturation index (ODI) and Epworth sleepiness scale (ESS) metrics and the Childhood Trauma Questionnaire (CTQ). All significant models were additionally adjusted for obesity, depression, metabolic syndrome, risky health behaviors, and socioeconomic factors. RESULTS: While both AHI and ESS were positively associated with the CTQ sum score, ODI was not. Investigating the CTQ subscales, ESS was associated with emotional abuse and emotional neglect; AHI was associated with physical and sexual abuse as well as physical neglect. For both the sum score and the subscales of the CTQ, ESS effects were partially mediated by depressive symptoms, while AHI effects were mediated by obesity, risky health behaviors, and metabolic syndrome. CONCLUSION: The findings of this general population study suggest an association between CM, particularly physical neglect, and objective as well as subjective indicators of sleep apnea, which were partially mediated by depressive symptoms and obesity.

A polysomnographic study of slow-wave sleep loss in elderly patients with epilepsy.

Objective: The primary objective is to explore what causes slow-wave sleep loss in elderly patients with epilepsy. The secondary objective is to identify the PSG characteristics in elderly patients with epilepsy. The clinical demographics, sleep architecture, sleep-related events, and interictal epileptiform discharges are to be evaluated in the objectives. Methods: The video electroencephalography (VEEG) and polysomnogram (PSG) data from 44 elderly patients with epilepsy and 52 elderly patients with sleep disorders but without definite central nervous system diseases were analysed. This was a case-control study. The differences in the PSG sleep architecture parameters (total sleep time (TST), sleep efficiency, wake after sleep onset, etc.) and sleep-related events (apnea hypopnea index, oxygen desaturation index (ODI), periodic limb movement index, etc.) between the epilepsy and control groups. As Additionally, these parameters were assessed within the elderly patients with epilepsy, comparing the slow-wave sleep existence and slow-wave sleep loss groups, using VEEG and PSG. Results: The epileptic group exhibited significantly lower TST (343.477 ± 96.3046min vs 389.115 ± 61.5727min, p < 0.05), rapid eye movement (%) (13.011 ± 7.5384 vs 16.992 ± 6.7025, p < 0.05), non-rapid eye movement stage 3 (%) (1.35[0,7.225] vs 3.65[0.425,13.75], p < 0.05), and sleep efficiency (%) (69.482 ± 14.1771% vs 77.242 ± 10.6171%, p < 0.05). Conversely, the ODI (25.6[9.825,51.775] events/hour vs 16.85[5.3,30.425] events/hour, p < 0.05) and spontaneous arousal index (4.0455[2.1805,6.9609] events/hour vs 2.9709[1.4747,5.0554] events/hour, p < 0.05) were significantly higher in elderly patients with epilepsy. The prevalence of obstructive sleep apnea-hypopnea syndrome (OSAHS) was significantly higher in the slow-wave sleep loss group than in the slow-wave sleep existence group (100% vs 77.8%, p < 0.05). The incidence of slow-wave sleep loss was lower in patients with epilepsy aged between 75 and 85 years compared to those aged between 65 and 75 years. Conclusion: Elderly patients with epilepsy exhibit higher levels of ODI and spontaneous arousal index. Our findings indicate that OSAHS could be a contributing factor to slow-wave sleep loss in this population. The incidence of slow-wave sleep loss was lower in patients aged above 75 years among elderly patients with epilepsy.

Veno-venous extracorporeal membrane oxygenation cannulation in prone position.

A 54-year-old woman was referred for veno-venous extracorporeal oxygenation membrane (VV-ECMO) due to refractory hypoxic respiratory failure caused by COVID-19, despite mechanical ventilation and prolonged prone positioning.

The effect of longitudinal sleep monitoring on clinician agreement in obstructive sleep apnea diagnosis: The ELSA study.

There is strong evidence for clinically relevant night-to-night variability of respiratory events in patients with suspected obstructive sleep apnea. Sleep experts retrospectively evaluated diagnostic data in 56 patients with suspected obstructive sleep apnea. Experts were blinded to the fact that they were diagnosing the same case twice, once based on a short report of a single in-laboratory respiratory polygraphy and once with the additional information of 14 nights of pulse oximetry at home. All experts (n = 22) were highly qualified, 13 experts (59.1%) treated > 100 patients with suspected obstructive sleep apnea per year. In 12 patients, the apnea-hypopnea index in the respiratory polygraphy was < 5 per hr, but the mean oxygen desaturation index of 14 nights of pulse oximetry was ≥ 5 per hr. The additional information of 14 nights of pulse oximetry helped to diagnose obstructive sleep apnea with a 70% consensus in two of those patients (16.7% [95% confidence interval: 4.7/44.8]). In eight patients, experts could not agree to a 70% consensus regarding continuous positive airway pressure therapy recommendation after respiratory polygraphy. The additional information of multiple-night testing led to a consensus in three of those cases (37.5% [95% confidence interval: 14/69]). Change of obstructive sleep apnea diagnosis and continuous positive airway pressure recommendation was significantly negatively associated with the number of treated obstructive sleep apnea patients > 100 per year compared with 0-29 patients per year (Coef. [95% confidence interval] -0.63 [-1.22/-0.04] and -0.61 [-1.07/-0.15], respectively). Experts found already a high level of consensus regarding obstructive sleep apnea diagnosis, severity and continuous positive airway pressure recommendation after a single respiratory polygraphy. However, longitudinal sleep monitoring could help increase consensus in selected patients with diagnostic uncertainty.

Correlation between polysomnographic parameters and volumetric changes generated by maxillomandibular advancement surgery in patients with obstructive sleep apnea: a fluid dynamics study.

STUDY OBJECTIVES: Maxillomandibular advancement surgery (MMA) is a therapeutic option for obstructive sleep apnea (OSA). The main objective of this study was to determine the impact of MMA on the physical and airflow characteristics of the upper airway based on data obtained by computational fluid dynamics (CFD) and to correlate these data with polysomnography parameters. Other objectives included the identification of presurgical variables that could help avoid surgeries likely to have a low success rate. METHODS: This was a retrospective observational study of 18 patients with moderate-severe OSA who underwent MMA. Polysomnography and computed axial tomography imaging were performed before and after the surgery. Three-dimensional models for CFD study were made based on the images obtained. RESULTS: MMA achieved an average increase in airway volume of 43.75%, with a mean decrease in the maximum airway velocity of 40.3%. We found significant correlations between improved apnea-hypopnea index values and both the increase in airway volume and decrease in maximum airway speed. Patients with a maximum velocity of less than 7.2 m/s before the intervention had a high rate of surgical failure (43%). CONCLUSIONS: MMA generates a significant increase in the volume of the upper airway, which was associated with improved flow conditions in the CFD simulation. These findings also correlated with improved polysomnography parameters. Thus, CFD simulation on three-dimensional anatomical models of patients with OSA could contribute to the better selection of candidates for MMA. CITATION: Furundarena-Padrones L, Cabriada-Nuño V, Brunsó-Casellas J, et al. Correlation between polysomnographic parameters and volumetric changes generated by maxillomandibular advancement surgery in patients with obstructive sleep apnea: a fluid dynamics study. J Clin Sleep Med. 2024;20(3):371-379.

Effect of functional appliances on sleep-disordered breathing in Class II division 1 malocclusion children: Randomized controlled trial.

OBJECTIVES: A randomized controlled trial was undertaken to investigate the orthopaedic effect of functional appliances on the pharyngeal airway space and nocturnal breathing of children with skeletal class II due to mandibular retrusion. MATERIALS AND METHODS: Forty patients were randomized into a 1:1 ratio study (Twin block) group and a control (fixed appliance) group. Each group included equal numbers of boys and girls. Diagnosis with sleep-disordered breathing was not an inclusion criterion. The duration of the trial was 12 months (T0 - T12). Eligibility criteria included skeletal Class II division 1 malocclusion with mandibular retrognathism, SNA ≥82, SNB ≤78, ANB ≥4, overjet ≥6 mm, and patients in circumpubertal stage CVM2 and CVM3. The main outcomes were pharyngeal airway volume, oxygen desaturation index (ODI), and maximum expiratory pressure (MEP), while the secondary outcomes were skeletal and dental changes of the maxilla and mandible. Randomization was accomplished with random blocks of 20 patients with allocation concealed in sequentially numbered, opaque, and sealed envelopes. Blinding was only applicable for data analysis of radiographic measurements and data extracted from the pulse oximeter. RESULTS: The mean age of the patients was 10 ± 1.5 and 10 ± 1.2 at (T0) for the Twin Block and the control groups, respectively. The changes in the oropharyngeal (2.66 cc and 0.056; P = .03) and nasopharyngeal (1.3 cc and 0.84; P = .053) airway volumes for the Twin block and control groups, respectively, were significantly different for the oropharynx. There was a significant decrease in ODI by [median -3.55 (-5.05 to 0.50); P ≤ .001] and a significant increase [median 45 (0.0-110); P ≤ .001] in MEP for the Twin block group. A significant inverse correlation (r = -.589; P = .006) could be found between the total volume of the oropharynx and ODI. No serious harm was observed. CONCLUSIONS: The Twin block group showed significant change in oropharyngeal airway volume and improvement of nocturnal breathing. REGISTRATION: This trial was registered at https://www. CLINICALTRIALS: gov, registration number NCT04255511.

Relationship between ODI and sleep structure of obstructive sleep apnea and cardiac remodeling.

PURPOSE: The purpose of the study was to evaluate the quantitative relationship between Oxygen Desaturation Index (ODI) and sleep structure of obstructive sleep apnea (OSA) and cardiac remodeling. METHODS: In this study, patients were enrolled from January 2015 to October 2022, and were divided into 3 groups according to AHI: patients with AHI < 15, patients with 15 ≤ AHI < 30, and 260 patients with AHI ≥ 30. Stratified linear regression was used to analyze independent risk factors for cardiac remodeling in OSA. RESULTS: A total of 479 patients were enrolled. We found that compared with AHI < 15 group (n = 120), the group with AHI > 30 (n = 260) had increased left atrial anteroposterior diameter, left ventricular end-diastolic internal diameter, left ventricular posterior wall thickness, right ventricular anteroposterior diameter, and interventricular septal thickness (P < 0.05). The group with 15 ≤ AHI ≤ 30 (n = 99) had increased left atrial anteroposterior diameter (P < 0.05). Multivariate linear regression revealed that N2 sleep was an independent risk factor for left ventricular posterior wall thickness, with positive correlation (p < 0.05). N3 sleep was an independent risk factor for transverse right atrial diameter and right ventricular anteroposterior diameter, with negative correlation (P < 0.05). ODI was an independent risk factor for interventricular septal thickness, with positive correlation (P < 0.05). The arousal index was an independent risk factor for increased left atrial anteroposterior diameter, with positive correlation (P < 0.05). CONCLUSIONS: Increased ODI is an independent risk factor for interventricular septal thickness, while decreased slow wave sleep is an independent risk factor for right heart remodeling in OSA.