Nocturnal Hypoxemia Due to Obstructive Sleep Apnea Is an Independent Predictor of Poor Prognosis After Myocardial Infarction

Using Apnea-Hypopnea Duration per Hour to Predict Hypoxemia Among Patients with Obstructive Sleep Apnea

Purpose

To explore the role of the mean apnea-hypopnea duration (MAD) and apnea-hypopnea duration per hour (HAD) in hypoxemia and evaluate whether they can effectively predict the occurrence of hypoxemia among adults with OSA.

Patients and Methods

A total of 144 participants underwent basic information gathering and polysomnography (PSG). Logistic regression models were conducted to evaluate the best index in terms of hypoxemia. To construct the prediction model for hypoxemia, we randomly divided the participants into the training set (70%) and the validation set (30%).

Results

The participants with hypoxemia tend to have higher levels of obesity, diabetes, AHI, MAD, and HAD compared with non-hypoxemia. The most relevant indicator of blood oxygen concentration is HAD (r = 0.73) among HAD, MAD, and apnea-hypopnea index (AHI). The fitness of HAD on hypoxemia showed the best. In the stage of establishing the prediction model, the area under the curve (AUC) values of both the training set and the validation set are 0.95. The increased HAD would elevate the risk of hypoxemia [odds ratio (OR): 1.30, 95% confidence interval (CI): 1.13-1.49].

Conclusion

The potential role of HAD in predicting hypoxemia underscores the significance of leveraging comprehensive measures of respiratory disturbances during sleep to enhance the clinical management and prognostication of individuals with sleep-related breathing disorders.

Association between sleep apnea-specific hypoxic burden and severity of coronary artery disease

PURPOSE

Sleep apnea-specific hypoxic burden (SASHB) is a polysomnographic metric that comprehensively measures the degree of nocturnal desaturation caused by obstructive sleep apnea. This research was conducted to elucidate the relationship between SASHB and coronary artery disease (CAD) severity.

METHODS

We carried out a prospective study of hospitalized patients with CAD of unstable angina who were expected to undergo invasive coronary angiography at Beijing Anzhen Hospital from February to September 2023. SASHB values were calculated using a self-programmed C +  + program. Multivariable logistic regression analysis was applied to identify the association between SASHB and the prevalence of severe CAD, documented by the Gensini Score, and the SYNTAX (Synergy between Percutaneous Coronary Intervention With Taxus and Cardiac Surgery) Score.

RESULTS

This study enrolled 137 patients with a median age of 59 years, 96 (70.1%) of whom were male. A total of 125 (91.2%) patients had coronary stenosis of ≥ 50% in at least one location. Patients with a high SASHB of ≥ 18% min/h had a significantly higher Gensini Score (32.0 vs. 18.5, P = 0.002) and SYNTAX Score (14.0 vs. 7.0, P = 0.002) than those with a low SASHB. After adjusting for multiple covariates, a high SASHB was significantly associated with the prevalence of severe CAD, determined by a Gensini Score ≥ 21 (OR 2.67, P = 0.008) or a SYNTAX Score > 22 (OR 4.03, P = 0.016).

CONCLUSION

Our findings revealed a robust and independent association between SASHB and CAD severity in patients with unstable angina, highlighting the potential value of SASHB as a predictor of risk and a target for interventions aimed at preventing cardiovascular diseases.

TRIAL REGISTRATION

Chinese Clinical Trial Registry No. ChiCTR2300067991 on February 2, 2023.

Metabolomic profiles of sleep-disordered breathing are associated with hypertension and diabetes mellitus development

Sleep-disordered breathing (SDB) is a prevalent disorder characterized by recurrent episodic upper airway obstruction. Using data from the Hispanic Community Health Study/Study of Latinos (HCHS/SOL), we apply principal component analysis (PCA) to seven SDB-related measures. We estimate the associations of the top two SDB PCs with serum levels of 617 metabolites, in both single-metabolite analysis, and a joint penalized regression analysis. The discovery analysis includes 3299 individuals, with validation in a separate dataset of 1522 individuals. Five metabolite associations with SDB PCs are discovered and replicated. SDB PC1, characterized by frequent respiratory events common in older and male adults, is associated with pregnanolone and progesterone-related sulfated metabolites. SDB PC2, characterized by short respiratory event length and self-reported restless sleep, enriched in young adults, is associated with sphingomyelins. Metabolite risk scores (MRSs), representing metabolite signatures associated with the two SDB PCs, are associated with 6-year incident hypertension and diabetes. These MRSs have the potential to serve as biomarkers for SDB, guiding risk stratification and treatment decisions.

Obstructive sleep apnea and temporal changes in cardiac repolarization in patients undergoing coronary artery bypass grafting

STUDY OBJECTIVES

In coronary artery bypass grafting (CABG), abnormal cardiac repolarization is associated with adverse cardiovascular events that can be measured via the QTc interval. We investigated the impact of obstructive sleep apnea on the change in repolarization after CABG and the association of change in repolarization with the occurrence of major adverse cardiac and cerebrovascular events.

METHODS

A total of 1,007 patients from 4 hospitals underwent an overnight sleep study prior to a nonemergent CABG. Electrocardiograms of 954 patients (median age: 62 years; male: 86%; mean follow-up: 2.1 years) were acquired prospectively within 48 hours before CABG (T1) and within 24 hours after CABG (T2). QTc intervals were measured using the BRAVO algorithm by Analyzing Medical Parameters for Solutions LLC. The change in T2 from T1 for QTc (ΔQTc) was derived, and Cox regression was performed.

RESULTS

Compared with those without, patients who developed major adverse cardiac and cerebrovascular events (n = 115) were older and had (1) a higher prevalence of smoking, hypertension, diabetes mellitus, and chronic kidney disease; (2) a higher apnea-hypopnea index and oxygen desaturation index; and (3) a smaller ΔQTc. Cox regression analysis demonstrated a smaller ΔQTc to be an independent risk factor for major adverse cardiac and cerebrovascular events (hazard ratio: 0.997; P = .032). In the multivariable regression model, a higher oxygen desaturation index was independently associated with a smaller ΔQTc (correlation coefficient: -0.58; P < .001).

CONCLUSIONS

A higher preoperative oxygen desaturation index was an independent predictor of a smaller ΔQTc. ΔQTc within 24 hours after CABG could be a novel predictor of occurrence of major adverse cardiac and cerebrovascular events at medium-term follow-up.

CLINICAL TRIAL REGISTRATION

Registry: ClinicalTrials.gov; Name: Undiagnosed Sleep Apnea and Bypass OperaTion (SABOT); URL: https://classic.clinicaltrials.gov/ct2/show/NCT02701504; Identifier: NCT02701504.

CITATION

Teo YH, Yong CL, Ou YH, et al. Obstructive sleep apnea and temporal changes in cardiac repolarization in patients undergoing coronary artery bypass grafting. J Clin Sleep Med. 2024;20(1):49-55.

Major Adverse Cardiac and Cerebrovascular Events in Geriatric Patients with Obstructive Sleep Apnea: An Inpatient Sample Analysis

BACKGROUND

Obstructive sleep apnea (OSA) is associated with an increased risk of major cardiac and cerebrovascular events (MACCE). However, data on the burden and predictors of MACCE in geriatric patients with OSA (G-OSA) remain limited.

METHODS

Using the National Inpatient Sample from 2018, we identified G-OSA admissions (age ≥ 65 years) and divided them into non-MACCE vs. MACCE (all-cause mortality, stroke, acute myocardial infarction, and cardiac arrest). We compared the demographics and comorbidities in both cohorts and extracted the odds ratio (multivariate analysis) of MACCE and associated in-hospital mortality.

RESULTS

Out of 1,141,120 geriatric obstructive sleep apnea G-OSA admissions, 9.9% (113,295) had MACCE. Males, Asians, or the Pacific Islander/Native American race, and patients from the lowest income quartile revealed a higher MACCE rate. Significant clinical predictors of MACCE in elderly OSA patients on multivariable regression analysis in decreasing odds were pulmonary circulation disease (OR 1.47, 95% CI 1.31-1.66), coagulopathy (OR 1.43, 95% CI 1.35-1.50), peripheral vascular disease (OR 1.34, 95% CI 1.28-1.40), prior sudden cardiac arrest (OR 1.34, 95% CI 1.11-1.62), prior myocardial infarction (OR 1.27, 95% CI 1.22-1.33), fluid and electrolyte imbalances (OR 1.25, 95% CI 1.20-1.29), male sex (OR 1.22, 95% CI-1.18-1.26), hyperlipidemia (OR 1.20, 95% CI 1.16-1.24), low household income (OR 1.19, CI 1.13-1.26), renal failure (OR 1.15, 95% CI 1.12-1.19), diabetes (OR 1.14, 95% CI 1.10-1.17), metastatic cancer (OR 1.14, 95% CI 1.03-1.25), and prior stroke or TIA (OR 1.12, 95% CI 1.07-1.17) (All p value < 0.05).

CONCLUSIONS

This study emphasizes the significant association between obstructive sleep apnea (OSA) and major cardiac and cerebrovascular events (MACCE) in the geriatric population. Among the elderly OSA patients, a substantial 9.9% were found to have MACCE, with specific demographics like males, Asian or Pacific Islander/Native American individuals, and those from the lowest income quartile being particularly vulnerable. The study sheds light on several significant clinical predictors, with pulmonary circulation disease, coagulopathy, and peripheral vascular disease topping the list. The highlighted predictors provide valuable insights for clinicians, allowing for better risk stratification and targeted interventions in this vulnerable patient cohort. Further research is essential to validate these findings and inform how tailored therapeutic approaches for geriatric OSA patients can mitigate MACCE risk.

CLINICAL IMPLICATIONS

Elderly individuals with a high risk for MACCE should undergo routine OSA screening using tools like the sensitive STOP-BANG Questionnaire. Implementing CPAP treatment can enhance cardiovascular outcomes in these patients.

The need to promote sleep health in public health agendas across the globe

Healthy sleep is essential for physical and mental health, and social wellbeing; however, across the globe, and particularly in developing countries, national public health agendas rarely consider sleep health. Sleep should be promoted as an essential pillar of health, equivalent to nutrition and physical activity. To improve sleep health across the globe, a focus on education and awareness, research, and targeted public health policies are needed. We recommend developing sleep health educational programmes and awareness campaigns; increasing, standardising, and centralising data on sleep quantity and quality in every country across the globe; and developing and implementing sleep health policies across sectors of society. Efforts are needed to ensure equity and inclusivity for all people, particularly those who are most socially and economically vulnerable, and historically excluded.

Effect of Sleep-Disordered Breathing on Exercise Capacity after Myocardial Infarction - A Cross-Sectional Study

Background

Exercise capacity reflects the cardiovascular risk after myocardial infarction (MI). The study aims to evaluate the impact of sleep-disordered breathing (SDB) on exercise capacity after MI.

Methods

Consecutive patients referring to outpatient cardiac rehabilitation up to 28 days after MI and participating in the Polish Managed Care after Acute Myocardial Infarction (MC-AMI) program were included. On admission, we assessed the presence and the severity of SDB using the home sleep apnea test (HSAT), patients' maximum exercise capacity on a treadmill exercise stress test (EST), and a 6-minute walk test (6MWT), as well as the effect of SDB on the results obtained. In the multivariate analysis, we verified the strength of the observed associations concerning age, anthropometric parameters, and left ventricular ejection fraction (LVEF).

Results

A total of 254 patients aged 60.00 (interquartile range 51.00-67.00), including 39 (15.4%) women, with technically adequate HSAT, constituted the study group. Mild SDB was found in 82 (32.3%), moderate in 54 (21.3%), and severe in 51 (20.1%) patients. Among those diagnosed with SDB, obstructive sleep apnea (OSA) was dominant in 167 (89.8%). With the worsening of SDB, the distance in 6MWT and the maximum physical exertion achieved in EST, expressed in metabolic equivalents (METs) and maximal heart rate (MHR), decreased. The linear regression analysis confirmed the following: (1) inversely proportional relationship between the respiratory event index and METs, MHR, and 6MWT distance (p = 0.005, p = 0.008, and p = 0.004), and the maximum apnea duration and MET and 6MWT distance (p = 0.042 and p = 0.002); and (2) directly proportional relationship between mean arterial oxygen saturation ( SpO 2 ) during sleep and MET, MHR, and 6MWT distance (p = 0.019, p = 0.006, and p = 0.013), and minimum SpO 2 and MET and MHR (p = 0.040 and p < 0.001). However, the independent risk factors for impaired exercise capacity, determined using multivariable regression analysis, were age, female sex, higher body mass index (BMI), and decreased LVEF, but not SDB parameters.

Conclusions

SDB negatively impacts exercise capacity after MI. However, the strength of this association may be less pronounced due to the interaction of risk factors common for SDB and impaired exercise capacity, e.g., sex, age, BMI, and LVEF.

International Consensus Statement on Obstructive Sleep Apnea

BACKGROUND

Evaluation and interpretation of the literature on obstructive sleep apnea (OSA) allows for consolidation and determination of the key factors important for clinical management of the adult OSA patient. Toward this goal, an international collaborative of multidisciplinary experts in sleep apnea evaluation and treatment have produced the International Consensus statement on Obstructive Sleep Apnea (ICS:OSA).

METHODS

Using previously defined methodology, focal topics in OSA were assigned as literature review (LR), evidence-based review (EBR), or evidence-based review with recommendations (EBR-R) formats. Each topic incorporated the available and relevant evidence which was summarized and graded on study quality. Each topic and section underwent iterative review and the ICS:OSA was created and reviewed by all authors for consensus.

RESULTS

The ICS:OSA addresses OSA syndrome definitions, pathophysiology, epidemiology, risk factors for disease, screening methods, diagnostic testing types, multiple treatment modalities, and effects of OSA treatment on multiple OSA-associated comorbidities. Specific focus on outcomes with positive airway pressure (PAP) and surgical treatments were evaluated.

CONCLUSION

This review of the literature consolidates the available knowledge and identifies the limitations of the current evidence on OSA. This effort aims to create a resource for OSA evidence-based practice and identify future research needs. Knowledge gaps and research opportunities include improving the metrics of OSA disease, determining the optimal OSA screening paradigms, developing strategies for PAP adherence and longitudinal care, enhancing selection of PAP alternatives and surgery, understanding health risk outcomes, and translating evidence into individualized approaches to therapy.

Obstructive sleep apnea and cardiovascular events in acute coronary syndrome: a meta-analysis

OBJECTIVE

Obstructive sleep apnea (OSA) in patients with the acute coronary syndrome (ACS) were at high risk for cardiovascular events, but the results are currently inconclusive. We aimed to conduct a systematic review to determine the incidence of cardiovascular events among ACS patients with OSA by a meta-analysis of observational studies.

METHODS

PubMed, Embase, and Cochrane Library were searched for studies related to the association between OSA and the risk of cardiovascular events in patients with ACS. Risk of bias in observational studies was assessed according to the Risk Of Bias In the Non-randomized Studies-Of Interventions tool.We performed a meta-analysis using a random-effects model to calculate estimates of pooled hazard ratios (HR) with 95% confidence intervals (CI), and heterogeneity was assessed using the statistics.

RESULTS

A total of 12 studies evaluating ACS patients with OSA were included in the meta-analysis. OSA was related to the increased risk of MACE (HR = 2.2; 95% CI, 1.274-3.805, I2  = 76.1%). The effect of OSA on MACCE (HR = 1.921; 95% CI, 1.45-2.546; I2  = 19.1%) and readmission for unstable angina (HR = 3.137, 95% CI, 1.06-9.283; I2  = 52.4%) were statistically significant in the pooled analysis. All of the outcomes in the included studies had a serious risk of bias and the Grading of Recommendation, Assessment, Development, and Evaluation evidence level of all the evaluation results were very low.

CONCLUSIONS

OSA was associated with a significant increase in the risk of cardiovascular events for patients with ACS. Additional randomized controlled trial studies are required to confirm the results and to prove the treatment of OSA can change the prognosis.

The Usefulness of Questionnaires in Assessing the Risk of Obstructive Sleep Apnea in Patients in the Managed Care after Acute Myocardial Infarction Program-The Results of a Cross-Sectional Study

Obstructive sleep apnea (OSA) worsens prognosis after myocardial infarction (MI) but often remains undiagnosed. The study aimed to evaluate the usefulness of questionnaires in assessing the risk of OSA in patients participating in managed care after an acute myocardial infarction program. Study group: 438 patients (349 (79.7%) men) aged 59.92 ± 10.92, hospitalized in the day treatment cardiac rehabilitation department 7-28 days after MI. OSA risk assessment: A 4-variable screening tool (4-V), STOP-BANG questionnaire, Epworth sleepiness scale (ESS), and adjusted neck circumference (ANC). The home sleep apnea testing (HSAT) was performed on 275 participants. Based on four scales, a high risk of OSA was found in 283 (64.6%) responders, including 248 (56.6%) based on STOP-BANG, 163 (37.5%) based on ANC, 115 (26.3%) based on 4-V, and 45 (10.3%) based on ESS. OSA was confirmed in 186 (68.0%) participants: mild in 85 (30.9%), moderate in 53 (19.3%), and severe in 48 (17.5%). The questionnaires' sensitivity and specificity in predicting moderate-to-severe OSA were: for STOP-BANG-79.21% (95% confidence interval; CI 70.0-86.6) and 35.67% (95% CI 28.2-43.7); ANC-61.39% (95% CI 51.2-70.9) and 61.15% (95% CI 53.1-68.8); 4-V-45.54% (95% CI 35.6-55.8) and 68.79% (95% CI 60.9-75.9); ESS-16.83% (95% CI 10.1-25.6) and 87.90% (95% CI 81.7-92.6). OSA is common in post-MI patients. The ANC most accurately estimates the risk of OSA eligible for positive airway pressure therapy. The sensitivity of the ESS in the post-MI population is insufficient and limits this scale's usefulness in risk assessment and qualification for treatment.

Clinical significance of obstructive sleep apnea in patients with acute coronary syndrome with or without prior stroke: a prospective cohort study

BACKGROUND AND OBJECTIVE

Whether obstructive sleep apnea (OSA) is associated with worse prognosis in patients with acute coronary syndrome (ACS) with or without prior stroke remains unclear. We investigated the association of OSA with cardiovascular events in ACS patients with or without prior stroke.

METHODS

Between June 2015 and January 2020, we prospectively recruited eligible ACS patients who underwent cardiorespiratory polygraphy during hospitalization. We defined OSA as an apnea hypopnea index (AHI) ≥ 15 events/hour. The primary composite end point was major adverse cardiovascular and cerebrovascular events (MACCEs), including cardiovascular death, myocardial infarction, stroke, ischemia-driven revascularization, or hospitalization for unstable angina or heart failure.

RESULTS

Among 1927 patients enrolled, 207 patients had prior stroke (10.7%) and 1014 had OSA (52.6%). After a mean follow-up of 2.9 years, patients with stroke had significantly higher risk of MACCEs than those without stroke (hazard ratio [HR]:1.49; 95% confidence interval [CI]: 1.12-1.98, P = 0.007). The multivariate analysis showed that patients with OSA had 2.0 times the risk of MACCEs in prior stroke group (41 events [33.9%] vs 18 events [20.9%]; HR:2.04, 95% CI:1.13-3.69, P = 0.018), but not in non-prior stroke group (186 events [20.8%] vs 144 events [17.4]; HR:1.21, 95% CI 0.96-1.52, P = 0.10). No significant interaction was noted between prior stroke and OSA for MACCE (interaction P = 0.17).

CONCLUSIONS

Among ACS patients, the presence of OSA was associated with an increased risk of cardiovascular events in patients with prior stroke. Further trials exploring the efficacy of OSA treatment in high-risk patients with ACS and prior stroke are warranted. Trial registration Clinicaltrials.gov identifier NCT03362385.

Should we treat with continuous positive airway pressure severe non-sleepy obstructive sleep apnea individuals without underlying cardiovascular disease?

The majority of the current international obstructive sleep apnea (OSA) guidelines base the recommendation to treat OSA with continuous positive airway pressure (CPAP) on the presence of symptoms (principally, albeit not exclusively on daytime hypersomnolence). In nonsleepy patients, even with severe OSA, controversies remain, as clear evidence supporting CPAP treatment of this subgroup of OSA patients is lacking. However, given the nonnegligible proportion of non-sleepy OSA patients, clinicians often face a serious dilemma since CPAP treatment in these patients may prove to be not cost-effective. Here, we propose a simple three-step-based algorithm that attempts to better phenotype non-sleepy OSA patients prior to reaching a CPAP treatment decision while also considering a series of clinically relevant elements in the process that may improve with CPAP therapy. Such algorithm focuses on the presence of several OSA symptoms that are susceptible to benefit from treatment and also relies on OSA phenotypes that need to be considered in an effort to achieve optimal cardiovascular prevention. Here, we attempt to establish a framework for clinicians who are evaluating severe nonsleepy OSA patients in their practices. However, the algorithm proposal needs to be extensively validated before being systematically implemented in clinical settings.

Sleep apnea is associated with the increase of certain genera of Ruminococcaceae and Lachnospiraceae in the gut microbiome of hypertensive patients

BACKGROUND

Obstructive sleep apnea (OSA) and hypertension are interrelated diseases linked to gut dysbiosis. This study aimed to investigate the effect of OSA on the gut microbiome in the context of hypertension and vice versa.

RESEARCH DESIGN AND METHODS

Of 211 consecutively screened patients, 52 completed polysomnography study, medical history questionnaires, and fecal sample collection. 16S rRNA gene sequencing was performed on fecal samples, and diversity, richness, and microbial taxa were analyzed using bioinformatics.

RESULTS

Alpha diversity showed slightly decreased diversity in OSA and hypertension groups without significant difference, and the hypoxia burden index (HBI) showed a weak positive correlation with Chao1 index (r = 0.342, p < 0.05) in OSA patients. Firmicutes-to-Bacteroidetes ratio was higher in patients with than without OSA. In hypertensive patients, those with OSA had higher Ruminococcus_1, Lachnoclostridium, Lachnospira, [Ruminococcus]_torques_group, and unidentified Lachnospiraceae levels than those without OSA. Conversely, in OSA patients, hypertensive patients had lower Faecalibacterium and Lachnospiraceae_NK4A136_group levels.

CONCLUSION

The present study suggests a possible compensatory mechanism for gut microbiome changes in sleep apnea pathophysiology. The positive correlation between HBI and alpha diversity, and increase in certain genera of Ruminococcaceae and Lachnospiraceae in OSA patients may represent an adaptive response to hypoxia.

Association of obstructive sleep apnea and nocturnal hypoxemia with all-cancer incidence and mortality: a systematic review and meta-analysis

STUDY OBJECTIVES

Biological models suggest that obstructive sleep apnea (OSA) is potentially carcinogenic. We aimed to clarify the inconsistent epidemiological literature by considering various traditional and novel OSA severity indices.

METHODS

We systematically searched PubMed, Embase, Scopus, and the Cochrane Library for observational or randomized studies of associations of OSA, measured by diagnostic codes or any index, each with all-cancer incidence or mortality in adults, compared with participants with no/mild OSA. Two reviewers independently selected studies, extracted data, and evaluated study bias using the Newcastle-Ottawa scale and quality of evidence using GRADE (Grading of Recommendations Assessment, Development, and Evaluation). We performed inverse variance-weighted, random-effects meta-analyses and sensitivity analyses.

RESULTS

We included 20 observational studies (5,340,965 participants), all with moderate/low bias, from 1,698 records. Based on T90 (sleep duration with oxygen saturation < 90%), patients with OSA who had moderate (T90 > 1.2%, hazard ratio [HR] = 1.28, 95% confidence interval [CI] = 1.07-1.54) and severe nocturnal hypoxemia (T90 > 12%, HR = 1.43, 95% CI = 1.16-1.76) experienced 30%-40% higher pooled all-cancer risk than normoxemic patients, after multiple adjustment for covariates including obesity. Furthermore, severe nocturnal hypoxemia nearly tripled all-cancer mortality (HR = 2.66, 95% CI = 1.21-5.85). Patients with apnea-hypopnea index-defined severe OSA, but not moderate OSA, had higher all-cancer risk (HR = 1.18, 95% CI = 1.03-1.35) but similar all-cancer mortality as patients without OSA. An OSA diagnosis was not associated with all-cancer risk. Evidence quality ranged from low to moderate. Insufficient evidence was available on the oxygen desaturation index, lowest/median saturation, and arousal index.

CONCLUSIONS

In patients with OSA, nocturnal hypoxemia is independently associated with all-cancer risk and mortality. Future studies should explore if risk differs by cancer type, and whether cancer screening and OSA treatment are beneficial.

SYSTEMATIC REVIEW REGISTRATION

Registry: PROSPERO; URL: https://www.crd.york.ac.uk/prospero/display_record.php?RecordID=220836; Identifier: CRD42021220836.

CITATION

Tan BKJ, Teo YH, Tan NKW, et al. Association of obstructive sleep apnea and nocturnal hypoxemia with all-cancer incidence and mortality: a systematic review and meta-analysis. J Clin Sleep Med. 2022;18(5):1427-1440.

Disparities in oxygen saturation and hypoxic burden levels in obstructive sleep apnea patient's response to oral appliance treatment

Background

Oxygen saturation indices show a strong correlation with long‐term health outcomes. Nonetheless, evidence on the relationship between reduction in respiratory events and increase in oxygenation levels following oral appliance (OA) treatment is scarce.

Objectives

To verify the relationship between reduction in the apnoea‐hypopnoea index (AHI) and oxygen saturation levels following OA treatment, we have conducted an evaluation of polysomnography (PSG) and clinical parameters associated with the improvement of oxygen desaturation.

Methods

OSA patients (n = 48) who received an OA and had pre‐ and post‐treatment PSG were classified into three responder groups according to the change in AHI and min O₂ post‐treatment: responder_AHIonly (decrease in AHI of ≥50% but increase in min O₂ level of <4% or decrease); responder_MinO2only (increase in min O₂ level of ≥4% but decrease in AHI <50% or increase) and responder_Congruous (decrease in AHI of ≥50% and increase in min O₂ level of ≥4%). Various demographic and PSG variables were statistically compared among groups.

Results

There were 26 (54.17%) responder_AHIonly, 9 (18.75%) responder_MinO2only and 13 (27.08%) responder_Congruous. Pre‐treatment min O₂ was significantly lower in responder_MinO2only. A higher pre‐treatment min O₂ showed a significant correlation with a smaller amount of change in mean O₂ (r = −.486) and min O₂ (r = −.764) with treatment. Pre‐treatment min O₂ showed the strongest ability to predict those who would show a ≥4% min O₂ increase following treatment.

Conclusion

Certain patients do not show sufficient decrease in hypoxaemia in spite of the improvement in AHI. Pre‐treatment min O₂ should be considered in OA treatment planning regarding its close relation to improvements in oxygenation levels with treatment.

Obstructive sleep apnea in patients with acute aortic dissection

Background

Obstructive sleep apnea (OSA) imposes an afterload burden on the left ventricle and increases the pressure gradient across the aortic wall. Thus, OSA may increase the risk for aortic dissection (AD).

Methods

This study enrolled 40 subjects with acute AD from four institutions; 37 completed the modified Berlin Questionnaire and 31 underwent attended overnight polysomnography. Aortic diameter was measured on a computed tomography scan at seven locations from the sinotubular junction to the diaphragm.

Results

Twenty‐seven subjects had type A dissection; 13 had type B. In those who had polysomnography apnea–hypopnea index (AHI) ranged from 0.7 to 89. Prevalence of OSA (AHI ≥ 5) was 61%. Nocturnal presentation (10 p.m.–7 a.m.) did not differ by presence/absence of OSA. The modified Berlin Questionnaire was not predictive of the presence of OSA. Among type A subjects with polysomnography (n = 23), aortic diameters at all locations were greater in the OSA group though differences were not statistically significant. Summating aortic diameters at the seven locations also yielded a numerically larger mean value in the OSA group versus the non‐OSA group.

Conclusions

In this sample of patients with acute dissection, OSA was prevalent but was not associated with a nocturnal presentation. The presence of underlying OSA may be associated with larger aortic diameters at the time of dissection compared to patients without OSA. Though differences did not meet statistical significance the current series is limited by small numbers.

OSA and cardiorespiratory fitness: a review

The effects of untreated obstructive sleep apnea (OSA) on cardiopulmonary function remain unclear. Cardiorespiratory fitness (CRF), commonly reflected by VO₂ max measured during cardiopulmonary exercise testing, has gained popularity in evaluating numerous cardiopulmonary conditions and may provide a novel means of identifying OSA patients with the most clinically significant disease. This emerging testing modality provides simultaneous assessment of respiratory and cardiovascular function with results helping uncover evidence of evolving pathology in either organ system. In this review, we highlight the current state of the literature in regard to OSA and CRF with a specific focus on changes in cardiovascular function that have been previously noted. While OSA does not appear to limit respiratory function during exercise, studies seem to suggest an abnormal cardiovascular exercise response in this population including decreased cardiac output, a blunted heart rate response (ie, chronotropic incompetence), and exaggerated blood pressure response. Surprisingly, despite these observed changes in the cardiovascular response to exercise, results involving VO₂ max in OSA remain inconclusive. This is reflected by VO₂ max studies involving middle-aged OSA patients showing both normal and reduced CRF. As prior studies have not extensively characterized oxygen desaturation burden, we propose that reductions in VO₂ max may exist in OSA patients with only the most significant disease (as reflected by nocturnal hypoxia). Further characterizing this relationship remains important as some research suggests that positive airway pressure therapy or aerobic exercise may improve CRF in patients with OSA. In conclusion, while it likely that severe OSA, via an abnormal cardiovascular response to exercise, is associated with decreased CRF, further study is clearly warranted to include determining if OSA with decreased CRF is associated with increased morbidity or mortality.

CITATION

Powell TA, Mysliwiec V, Brock MS, Morris MJ. OSA and cardiorespiratory fitness: a review. J Clin Sleep Med. 2022;18(1):279-288.

Differentiation Model for Insomnia Disorder and the Respiratory Arousal Threshold Phenotype in Obstructive Sleep Apnea in the Taiwanese Population Based on Oximetry and Anthropometric Features

Insomnia disorder (ID) and obstructive sleep apnea (OSA) with respiratory arousal threshold (ArTH) phenotypes often coexist in patients, presenting similar symptoms. However, the typical diagnosis examinations (in-laboratory polysomnography (lab-PSG) and other alternatives methods may therefore have limited differentiation capacities. Hence, this study established novel models to assist in the classification of ID and low- and high-ArTH OSA. Participants reporting insomnia as their chief complaint were enrolled. Their sleep parameters and body profile were accessed from the lab-PSG database. Based on the definition of low-ArTH OSA and ID, patients were divided into three groups, namely, the ID, low- and high-ArTH OSA groups. Various machine learning approaches, including logistic regression, k-nearest neighbors, naive Bayes, random forest (RF), and support vector machine, were trained using two types of features (Oximetry model, trained with oximetry parameters only; Combined model, trained with oximetry and anthropometric parameters). In the training stage, RF presented the highest cross-validation accuracy in both models compared with the other approaches. In the testing stage, the RF accuracy was 77.53% and 80.06% for the oximetry and combined models, respectively. The established models can be used to differentiate ID, low- and high-ArTH OSA in the population of Taiwan and those with similar craniofacial features.

Waist-To-Hip Ratio Predicts Abnormal Overnight Oximetry in Men Independent of Body Mass Index

Background: Ambulatory overnight oximetry (OXI) has emerged as a cost-effective initial test for sleep disordered breathing. Obesity is closely associated with obstructive sleep apnea (OSA); however, whether body mass index (BMI) or waist-to-hip ratio (WHR) predicts abnormal overnight OXI remains unknown. Methods: We performed a retrospective cross-sectional study of 393 men seen in the Executive Health Program at Mayo Clinic in Rochester, Minnesota who underwent ambulatory overnight OXI ordered by preventive medicine physicians between January 1, 2004 through December 31, 2010. We compared participant/spouse-reported symptoms (sleepiness, snoring), physician indications for OXI (obesity, fatigue), Epworth Sleepiness Scale scores, anthropomorphic measurements (WHR, BMI), and comorbid medical conditions (hypertension, diabetes) with OXI results. Results: 295 of the 393 men who completed OXI had abnormal results. During multivariate analysis, the strongest independent predictor of abnormal OXI for men was WHR (≥1.0, OR = 5.59) followed by BMI (≥30.0 kg/m2, OR = 2.75), age (≥55 yrs, OR = 2.06), and the presence of snoring (OR = 1.91, P < 0.05 for all). A strong association was observed between WHR and abnormal OXI in obese (BMI ≥ 30.0 kg/m2, OR = 6.28) and non-obese (BMI < 29.9 kg/m2, OR = 6.42, P < 0.01 for both) men. Furthermore, 88 men with abnormal OXI underwent polysomnography with 91% being subsequently diagnosed with OSA. Conclusions: In ambulatory, predominantly middle-aged men undergoing preventive services evaluation many physician indications for OXI were not predictors of abnormal results; however, WHR strongly predicted abnormal OXI in obese and non-obese men. As such, we suggest middle-aged men who snore and have a WHR ≥1.0 should be directly referred to a sleep clinic for polysomnography.

Obstructive Sleep Apnea and Cardiac Arrhythmias: A Contemporary Review

Obstructive sleep apnea (OSA) is a highly prevalent disorder with a growing incidence worldwide that closely mirrors the global obesity epidemic. OSA is associated with enormous healthcare costs in addition to significant morbidity and mortality. Much of the morbidity and mortality related to OSA can be attributed to an increased burden of cardiovascular disease, including cardiac rhythm disorders. Awareness of the relationship between OSA and rhythm disorders is variable among physicians, a fact that can influence patient care, since the presence of OSA can influence the incidence, prevalence, and successful treatment of multiple rhythm disorders. Herein, we provide a review of this topic that is intentionally broad in scope, covering the relationship between OSA and rhythm disorders from epidemiology and pathophysiology to diagnosis and management, with a particular focus on the recognition of undiagnosed OSA in the general clinical population and the intimate relationship between OSA and atrial fibrillation.

Diagnostic accuracy of the Berlin questionnaire and the NoSAS score in detecting risk for obstructive sleep apnea in rotating shift workers

BACKGROUND

Data on the validity of tools for sleep apnea risk detection in rotating shift workers are limited. The aim was to evaluate the Berlin questionnaire (BQ) and the Neck, Obesity, Snoring, Age, Sex (NoSAS) score for the detection of obstructive sleep apnea risk in shift workers.

METHODS

This cross-sectional study included male rotating shift workers, drivers of heavy off-road machinery in an iron ore extraction company. Polysomnography was the gold standard for evaluation. Obstructive sleep apnea (OSA) was defined as an apnea-hypopnea index (AHI) of ≥ 5 events/h. The Shapiro-Wilk test verified the data distribution and comparative analysis was conducted using the chi-square analyses and U Mann-Whitney with Bonferroni correction. Receiver operating characteristic curve analysis, sensitivity, specificity, positive and negative predictive values, positive and negative likelihood ratios, and accuracy were used for evaluate BQ and NoSAS with OSA diagnosis by polysomnograph.

RESULTS

Among 119 male shift workers, ages 24 to 57 years, polysomnography showed that 84% had obstructive sleep apnea (AHI ≥ 5), and 46% had moderate to severe sleep apnea (AHI ≥ 15). For AHI ≥ 5, the NoSAS score had higher sensitivity and specificity than the BQ. For AHI ≥ 15 and AHI ≥ 30, the NoSAS score had a sensitivity higher than 70% while BQ was 60% and 58%, respectively. The accuracy of the NoSAS score was higher for all OSA criteria than that of BQ.

CONCLUSION

In rotating shift workers, drivers of heavy off-road machinery, the NoSAS score showed higher accuracy in identifying patients at risk for sleep apnea than the BQ.

Changes in platelet count and coagulation parameters in children with obstructive sleep apnea

OBJECTIVE

To investigate the correlation between obstructive sleep apnea (OSA) and coagulation status and to speculate on the underlying mechanism in children with OSA.

METHODS

We divided 345 children with OSA (age 2-14 years) into four groups according to the apnea-hypopnea index (AHI). We compared platelet (PLT) and coagulation parameters among groups. Correlations between the polysomnography parameters and coagulation parameters were investigated.

RESULTS

Children with OSA had higher PLT counts than those without OSA (P < 0.001), while no significant difference was observed in prothrombin time, international normalized ratio, activated partial thromboplastin time, thrombin time, or fibrinogen among children with/without OSA. In linear regression analysis, the AHI and oxygen desaturation index (ODI) presented positive correlation with the PLT count (R² = 0.155, beta = 0.307, P < 0.001 and R² = 0.113, beta = 0.262, P < 0.001), and there was no correlation among the AHI, ODI, and other coagulation parameters. The minimum and mean oxygen saturation of arterial blood manifested negative correlation with the PLT count (R² = 0.076, beta =  - 0.116, P = 0.034 and R² = 0.083, beta =  - 0.140, P = 0.008, respectively).

CONCLUSIONS

Children with OSA have a higher PLT count, positively correlated with OSA severity, and no evidence of coagulation disorder.

The potential of miR-499 plasmatic level as a biomarker of obstructive sleep apnea syndrome

Background: Obstructive sleep apnea syndrome (OSAS) is one of the most common sleep-related breathing disorders. The aim of this study was to improve diagnostics in OSAS using blood circulating biomarkers. We consider the potential of cardiac-specific miRNAs in the diagnosis and risk assessment of cardiovascular complications. Materials & methods: Plasmatic levels of miR-1-3p, miR-133a-3p and miR-499a-5p were measured by reverse transcription-PCR and compared with the clinical status of OSAS patients and controls. Results: The level of miR-499 was higher (p = 0.0343) in OSAS patients (mean expression: 0.00561) compared with the controls (mean expression: 0.00003), using the multivariate logistic regression. Conclusion: The role of miR-499 in gene expression regulation during hypoxia and our findings indicate that miR-499 could be a new diagnostic biomarker for OSAS.

Validation of an obstructive sleep apnea symptom inventory in persons with multiple sclerosis

BACKGROUND

Improved screening for obstructive sleep apnea (OSA) could enhance multiple sclerosis (MS) clinical care; yet the utility of current screening tools for OSA have yet to be evaluated in persons with multiple sclerosis (PwMS).

OBJECTIVES

The STOP-Bang Questionnnaire is an 8-item screening tool for OSA that is commonly used in non-MS samples. The aim of this study was to assess the validity of the STOP-Bang in PwMS.

METHODS

STOP-Bang and polysomnography data were analyzed from n = 200 PwMS. Sensitivity, specificity, positive-, and negative-predictive value (PPV and NPV) were calculated, with receiving operating characteristic (ROC) curves, for each STOP-Bang threshold score, against polysomnography-confirmed OSA diagnosis at three apnea severity thresholds (mild, moderate, and severe).

RESULTS

Nearly 70% had a STOP-Bang score of ⩾3% and 78% had OSA. The STOP-Bang at a threshold score of 3 provided sensitivities of 87% and 91% to detect moderate and severe OSA, respectively; and NPV of 84% and 95% to identify PwMS without moderate or severe OSA, respectively. Sensitivity to detect milder forms of OSA was 76%. The NPV to identify persons without milder forms of OSA was 40%.

CONCLUSION

The STOP-Bang Questionnaire is an effective tool to screen for moderate and severe OSA in PwMS, but may be insufficient to exclude mild OSA.

Association of Obstructive Sleep Apnea With the Risk of Repeat Adverse Cardiovascular Events in Patients With Newly Diagnosed Acute Coronary Syndrome: A Systematic Review and Meta-Analysis

BACKGROUND

The impact of obstructive sleep apnea (OSA) on subsequent cardiovascular events in patients with acute coronary syndrome (ACS) remains inconclusive.

AIM

Our aim was to systematically assess the relationship between preexisting OSA and adverse cardiovascular events in patients with newly diagnosed ACS by conducting a systematic review and meta-analysis.

METHODS

We systematically searched PubMed, EMBASE, and Cochrane library for studies published up to May 1, 2020, that reported any association between OSA and cardiovascular events in patients with newly diagnosed ACS. The main outcomes were a composite of all-cause or cardiovascular death, recurrent myocardial infarction, stroke, repeat revascularization, or heart failure. We conducted a pooled analysis using the random-effects model. We also performed subgroup, sensitivity, heterogeneity analysis, and the assessment of publication bias.

RESULTS

We identified 10 studies encompassing 3350 participants. The presence of OSA was associated with increased risk of adverse cardiovascular events in newly prognosed ACS (risk ratio [RR] 2.18, 95% confidence interval [CI]: 1.45-3.26, P < .001, I2 = 64%). Between-study heterogeneity was partially explained by a multicenter study (9 single-center studies, RR 2.33 95% CI 1.69-3.19, I2 =18%), and I2 remarkably decreased from 64% to 18%. Moreover, OSA significantly increased the incidence of repeat revascularization (8 studies) and heart failure (6 studies) in patients with newly diagnosed ACS.

CONCLUSION

Patients with preexisting OSA are at greater risk of subsequent cardiovascular events after onset of ACS. Further studies should investigate the treatment of OSA in patient with ACS.

Sleep apnea, "the Ugly Duckling of the Cinderellas" in cardiovascular prevention and rehabilitation

Cardiovascular diseases are the leading cause of death and account for the largest share of health expenditure worldwide, mainly invested in hospital and secondary care. Prevention and rehabilitation strategies are nearly neglected, therefore "the Cinderellas," in the health-care budget. The World Health Organization has proposed cost-effective interventions to reduce the impact of cardiovascular diseases that include polydrug treatment for hypertension and diabetes, counselling, diet, exercise, and others. Obstructive sleep apnea is not even mentioned among these interventions; consequently, it could be "the Ugly Duckling of the Cinderellas." Obstructive sleep apnea (OSA) is characterized by the presence of obstructive apneas or hypopneas during sleep, accompanied by hypoxia; and it is a highly prevalent but under-diagnosed condition. Although awareness of sleep apnea has recently increased most facts about it remains ignored by many. Robust evidence suggests that OSA is associated with, or is an independent risk factor for, hypertension, cerebrovascular disease, ischemic heart disease, heart failure and arrhythmias and that its prevalence among some of these cardiovascular diseases is higher than 80%. The efficacy of continuous positive airway pressure treatment for obstructive sleep apnea has been established. If obstructive sleep apnea plays a significant role in cardiovascular diseases, then screening and timely appropriate treatment could reduce morbidity and mortality. Thus, the public health and economic impact of these conditions could be included in the "best buy" list of interventions. This narrative review discusses the relationship between OSA and cardiovascular diseases and how neglected the link is.

A novel parameter is better than the AHI to assess nocturnal hypoxaemia and excessive daytime sleepiness in obstructive sleep apnoea

To evaluate whether the percentage of total sleep time spent with apnoea and hypopnoea duration time (AHT%) is better than the apnoea-hypopnoea index (AHI) for the assessment of nocturnal hypoxaemia and excessive daytime sleepiness (EDS) in patients with obstructive sleep apnoea (OSA). Patients with suspected OSA were enrolled. Polysomnography, Epworth Sleepiness Scale, self-administered surveys and anthropometric measures were performed. The efficiency of AHT% and the AHI was evaluated for nocturnal hypoxaemia and EDS. A total of 160 eligible participants were analysed. The median AHT% in normal, mild, moderate and severe OSA patients was significantly different in the four-group patients with OSA. Spearman rank correlations analysis found that the associations were stronger between AHT% with percentage of total sleep time and O₂ saturation of < 90% and minimum nocturnal oxygen saturation than these parameters with the AHI. AHT% had a greater area under the curve than the AHI for predicting EDS in patients with OSA. AHT% was significantly higher in the EDS group. We present a novel parameter, AHT%, to evaluate nocturnal hypoxaemia and EDS in OSA patients. AHT% partially compensates for the shortcomings of the AHI. AHT% is better than the AHI for assessing nocturnal hypoxaemia and EDS. AHT% reflects different clinical characteristics associated with OSA from a new perspective.

Obstructive Sleep Apnea as a Cardiovascular Risk Factor-Beyond CPAP

Patients with obstructive sleep apnea (OSA) experience repetitive partial or complete airway collapse during sleep resulting in nocturnal hypoxia-normoxia cycling, and are at increased cardiovascular risk. The number of apneas and hypopneas indexed per hour of sleep (apnea-hypopnea index) along with the associated intermittent hypoxia predict the increased cardiovascular risk; thus, their attenuation or prevention are objectives of OSA therapy. Continuous positive airway pressure (CPAP) is the gold standard treatment for OSA and, when effective, mitigates the apnea-hypopnea index and hypoxemia. As such, it is reasonable to expect CPAP would decrease cardiovascular risk. However, 3 recent randomized clinical trials of CPAP vs usual care did not show any significant effects of CPAP in attenuating incident cardiovascular events in patients with OSA. In this review, we discuss these studies in addition to potential complementary therapeutic options to CPAP (eg, neurostimulation) and conclude with suggested therapeutic targets for future interventional studies (eg, the autonomic nervous system). Although these areas of research are exciting, they have yet to be tested to any similar degree of rigour as CPAP.

Therapeutic value of treating central sleep apnea by adaptive servo-ventilation in patients with heart failure: A systematic review and meta-analysis

BACKGROUND

Despite the efficacy of adaptive servo-ventilation (ASV) in suppressing central sleep apnea (CSA), its impact on long-term outcomes is debatable. We aim to identify subjects with specific features who might benefit from ASV therapy.

METHODS

Randomized clinical trials and comparative observational studies investigating the effects of ASV on cardiovascular (CV) and all-cause mortality and major adverse cardiovascular events (MACEs) in CSA patients were searched from PubMed, EMBASE, Cochrane library and Web of Science. Eligible studies were identified with relative risks (RR) of death and MACEs compared between patients treated by ASV and usual care.

RESULTS

A total of eight studies (three randomized controlled trials and five observational studies) including 2208 participants were selected for analysis. All-cause and CV mortality were not significantly reduced by ASV. Patients with nadir nocturnal saturation ≤ 80% (mean value) had lower risk of MACEs by ASV treatment compared with by usual care (RR, 0.18; p < 0.001). Patients with severe heart failure (HF), defined as left ventricular ejection fraction (LVEF) ≤ 33% (mean value), or HF of New York Heart Association (NYHA) classification of III/IV, did not have reduced risk of MACEs post ASV therapy. However, subjects with LVEF > 33% (RR, 0.35; p < 0.001) or NYHA Ⅰ/Ⅱ (RR, 0.35; p < 0.001) had significantly lower risk of MACEs by using ASV than by usual care.

CONCLUSIONS

Although ASV appears to not reduce CV and all-cause death for HF patients with extremely low LVEF, those with profound CSA associated hypoxemia or less severe HF still benefit from ASV therapy.

Obstructive sleep apnea increases heart rhythm disorders and worsens subsequent outcomes in elderly patients with subacute myocardial infarction

OBJECTIVE

Obstructive sleep apnea (OSA) is a potential cardiovascular risk. We aimed to investigate the association of OSA with heart rhythm disorders and prognosis in elderly patients with new-onset acute myocardial infarction (AMI).

METHODS

We prospectively enrolled 252 AMI elderly patients (mean age, 68.5 ± 6.9 years) who were undergoing revascularization and completed a sleep study during their hospitalization. All subjects were categorized into non-OSA (apnea–hypopnea index (AHI) < 15, n = 130) and OSA (AHI ≥ 15, n = 122) groups based on the AHI. The changes in the autonomic nervous system, incidence of arrhythmia during nocturnal sleep, and major adverse cardiovascular and cerebrovascular events (MACCEs) were compared between the groups.

RESULTS

The mean AHI value in all AMI patients was 22.8 ± 10.9. OSA patients showed higher levels of body mass index and peak high-sensitivity C-reactive protein and lower levels of minimum nocturnal oxygen saturation (MinSaO₂), as well as greater proportion of multivessel coronary artery disease (all P < 0.05). The OSA group also showed significant increases in heart rate variability and heart rate turbulence onset (both P < 0.05) and higher incidence of arrhythmia (including sinus, atrial, and ventricular in origin). At a median follow-up of 6 months (mean 0.8–1.6 years), OSA (AHI ≥ 15) combined with hypoxia (MinSaO ₂ ≤ 80%) was independently associated with the incidence of MACCEs (hazard ratio [HR]: 4.536; 95% confidence interval [CI]: 1.461−14.084,P = 0.009) after adjusting for traditional risk factors.

CONCLUSIONS

OSA and OSA-induced hypoxia may correlate with the severity of myocardial infarction, increase the occurrence of heart rhythm disorders in elderly subacute MI patients, and worsen their short-term poor outcomes.

Evaluation of a multicomponent grading system for obstructive sleep apnoea: the Baveno classification

New findings on pathophysiology, epidemiology, and outcome have raised concerns on the relevance of the apnoea-hypopnoea index (AHI) in the classification of obstructive sleep apnoea (OSA) severity. Recently, a multicomponent grading system decision integrating symptomatology and comorbidities (Baveno classification), was proposed to characterise OSA and to guide therapeutic decisions. We evaluated whether this system reflects the OSA population, whether it translates into differences in outcomes, and whether the addition of AHI improves the scheme. A total of 14 499 OSA patients from the European Sleep Apnoea Database cohort were analysed. The groups were homogeneously distributed and were found to clearly stratify the population with respect to baseline parameters. Differences in sleepiness and blood pressure between the groups were analysed in a subgroup of patients after 24-36 months of treatment. Group A (minor symptoms and comorbidities) did not demonstrate any effect of treatment on outcome. However, groups B (severe symptoms, minor comorbidities), C (minor symptoms, severe comorbidities) and D (severe symptoms and comorbidities) were associated with improvement in either or both parameters with treatment. The AHI is an essential prerequisite of the diagnosis; however, adding the AHI did not improve the classification. Rather, it was inferior with respect to guiding the treatment decision. Thus, the Baveno classification allows a better stratification of the OSA population and may provide a better guidance for therapeutic decisions in OSA.

Impact of obstructive sleep apnea on left ventricular mass index in men with coronary artery disease

STUDY OBJECTIVES

Left ventricular hypertrophy (LVH) is associated with augmented risk for mortality in patients with coronary artery disease (CAD). These patients often have obstructive sleep apnea (OSA). We aimed to evaluate the relationship between OSA and the left ventricular mass index (LVMI) in men with CAD.

METHODS

Consecutive patients with CAD were recruited and underwent overnight portable monitoring for the assessment of OSA. LVMI was ascertained using high-resolution echocardiography. Univariate and multivariate regression analyses were conducted to explore the associations between the OSA parameters and the LVMI levels.

RESULTS

Of the 1,053 examined male patients with CAD, 425 (40.4%) had moderate-to-severe OSA (respiratory event index ≥ 15 events/h). The prevalence of LVH (LVMI > 125 g/m²) was 36.0% (n = 379). The mean LVMI values increased with increasing OSA severity (P < .001). Patients with respiratory event index ≥ 30 events/h had 2.30 (95% confidence interval 1.50-3.54, P < .001) times increased risk of LVH than those without OSA (respiratory event index < 5 events/h) independent of confounders. The minimum oxygen saturation levels were the strongest factor correlated with LVMI (β = -0.299, P = .004) of several OSA indices. Patients with minimum oxygen saturation < 70% had an adjusted odds ratio of 3.62 (95% confidence interval 1.81-7.25, P < .001) for LVH development compared with those with minimum oxygen saturation ≥ 90%.

CONCLUSIONS

OSA severity was associated with a higher likelihood of LVH in men with CAD, which is partially related to severe nocturnal intermittent hypoxemia. Aggressive effort at managing OSA among patients with CAD may further reduce the cardiovascular risk.

Hypoxemia and pulmonary hypertension in patients with concomitant restrictive ventilatory defect and sleep apnea: the overlap syndrome

BACKGROUND

To investigate the severity of hypoxemia and prevalence of pulmonary hypertension (PHTN) in patients with the overlap syndrome (OS) of restrictive ventilatory defect (RVD) and sleep apnea (SA).

METHODS

Patients referred for both sleep test and spirometry for suspected SA and ventilatory disorders were recruited prospectively from January 2019 to January 2020. SA was determined by an apnea-hypopnea index ≥ 5/h; average oxygen saturation during sleep (meanSaO₂) and percentage of total sleep time with saturation < 90% (T90) were calculated. RVD was diagnosed in the presence of forced expiratory volume in the first second/forced vital capacity (FVC) > 0.7 and FVC < 80% predicted value. PHTN was defined by tricuspid regurgitation peak velocity ≥ 3.4 m/s, documented by noninvasive transthoracic echocardiography.

RESULTS

Patients with OS had significantly lower meanSaO₂ but higher T90 than subjects with isolated SA and isolated RVD. Patients with OS vs. those with isolated SA had higher odds of PHTN in multivariable analysis with age, sex, and body mass index adjusted for (OR 2.96, 95%CI 1.05-8.91, p = 0.040). Patients with meanSaO₂ < 92% vs. meanSaO₂ ≥ 92% had significantly higher odds of being diagnosed with PHTN (OR 5.40, 95%CI 2.01-15.7, p < 0.001). Similarly, T90 (≥ 4.5% versus < 4.5%) was also independently associated with the prevalence of PHTN (OR 7.21, 95%CI 2.54-23.67, p < 0.001).

CONCLUSION

Patients with OS of RVD and SA had severe hypoxemia, which is associated with the prevalence of PHTN. Further investigation is needed to discern whether therapeutic strategies toward OS might mitigate PHTN in this cohort.

TRIAL REGISTRATION

Clinical Trial Registration No. ChiCTR1900027294 on 1 October 2019.

Use of the WatchPAT to detect occult residual sleep-disordered breathing in patients on CPAP for obstructive sleep apnea

STUDY OBJECTIVES

To determine the accuracy of the apnea-hypopnea index (AHI) as measured by continuous positive airway pressure (CPAP) machines by simultaneously employing a home sleep apnea testing device (WatchPAT 200, Itamar Medical, Israel [WPAT]) in patients suspected of having residual sleep-disordered breathing (SDB).

METHODS

Patients with new, recurrent, or worsening signs, symptoms, or comorbidities associated with obstructive sleep apnea underwent home sleep apnea testing using WPAT while simultaneously using CPAP at their usual prescribed settings. CPAP AHI and WPAT AHI, respiratory disturbance index, and oximetry readings were then compared.

RESULTS

We identified an elevated AHI with WPAT testing in nearly half of patients with clinically suspected residual SDB and a normal CPAP AHI. WPAT detected additional respiratory events as well, including rapid eye movement-related apneas, respiratory effort-related arousals, and hypoxemia.

CONCLUSIONS

WPAT AHI was significantly higher than simultaneous CPAP AHI in nearly half of those patients with clinically suspected residual SDB being treated with CPAP. Additional respiratory disturbances, including rapid eye movement-related respiratory events, respiratory effort-related arousals, and hypoxemia, were elucidated only with the use of the WPAT. Residual SDB may have potential clinical consequences, including reduced CPAP adherence, ongoing hypersomnolence, and other health-related sequelae. Simultaneous WPAT testing of patients with a normal CPAP AHI may represent a valuable tool to detect clinically suspected residual SDB or to ensure adequate treatment in high-risk patients with obstructive sleep apnea in general.

Low Prognostic Value of Novel Nocturnal Metrics in Patients With OSA and High Cardiovascular Event Risk: Post Hoc Analyses of the SAVE Study

BACKGROUND

Traditional methods for the quantification of OSA severity may not encapsulate potential relationships between hypoxemia in OSA and cardiovascular risk.

RESEARCH QUESTION

Do novel nocturnal oxygen saturation (Spo₂) metrics have prognostic value in patients with OSA and high cardiovascular event risk?

STUDY DESIGN AND METHODS

We conducted post hoc analyses of the Sleep Apnea Cardiovascular Endpoints (SAVE) trial. In 2687 individuals, Cox proportional hazards models that were stratified for treatment allocation were used to determine the associations between clinical characteristics, pulse oximetry-derived metrics that were designed to quantify sustained and episodic features of hypoxemia, and cardiovascular outcomes. Metrics included oxygen desaturation index, time <90% Spo₂, average Spo₂ for the entire recording (mean Spo₂), average Spo₂ during desaturation events (desaturation Spo₂), average baseline Spo₂ interpolated across episodic desaturation events (baseline Spo₂), episodic desaturation event duration and desaturation/resaturation-time ratio, and mean and SD of pulse rate.

RESULTS

Neither apnea-hypopnea index, oxygen desaturation index, nor any of the novel Spo₂ metrics were associated with the primary SAVE composite cardiovascular outcome. Mean and baseline Spo₂ were associated with heart failure (hazard ratio [HR], 0.81; 95% CI, 0.69-0.95; P = .009; and HR, 0.78; 95% CI, 0.67-0.90; P = .001, respectively) and myocardial infarction (HR, 0.86; 95% CI, 0.77-0.95; P = .003; and HR, 0.81; 95% CI, 0.73-0.90; P < .001, respectively). Desaturation duration and desaturation/resaturation time ratio, with established risk factors, predicted future heart failure (area under the curve, 0.86; 95% CI, 0.79-0.93).

INTERPRETATION

Apnea-hypopnea index and oxygen desaturation index were not associated with cardiovascular outcomes. In contrast, the pattern of oxygen desaturation was associated with heart failure and myocardial infarction. However, concomitant risk factors remained the predominant determinants for secondary cardiovascular events and thus deserve the most intensive management.

Prevalence of Undiagnosed Obstructive Sleep Apnea Among Patients Hospitalized for Cardiovascular Disease and Associated In-Hospital Outcomes: A Scoping Review

BACKGROUND

Obstructive sleep apnea (OSA) is associated with long-term cardiovascular morbidity and is highly prevalent in patients with cardiovascular disease (CVD). The objectives of this scoping review were to determine the prevalence of OSA inpatients hospitalized for CVD and to map the range of in-hospital outcomes associated with OSA.

METHODS

We searched MEDLINE(R), Embase, and Cochrane Databases for articles published from 1946-2018. We included studies involving non-surgical adults with OSA or at high risk of OSA who were hospitalized for CVD. The outcomes were considered as in-hospital if they were collected from admission up to 30 days post-discharge from hospital.

RESULTS

After the screening of 4642 articles, 26 studies were included for qualitative synthesis. Eligible studies included patients presenting with acute coronary syndromes (n = 19), congestive heart failure (n = 6), or any cardiovascular disease (n = 1). The pooled prevalence of OSA in cardiac inpatients was 48% (95% CI: 42-53). The in-hospital outcomes reported were mortality (n = 4), length of stay (n = 8), left ventricular ejection fraction (n = 8), peak troponin (n = 7), peak B-type natriuretic peptide (n = 4), and composite cardiovascular complications (n = 2).

CONCLUSIONS

OSA is highly prevalent in the cardiac inpatient population. The outcomes reported included mortality, cardiac function, cardiac biomarkers, and resource utilization. There are significant knowledge gaps regarding the effect of treatment and OSA severity on these outcomes. The findings from this review serve to inform further areas of research on the management of OSA among patients with CVD.

Sleep Disordered Breathing in Hypertrophic Cardiomyopathy-Current State and Future Directions

Hypertrophic cardiomyopathy (HCM) is the most common inherited cardiomyopathy and sleep disordered breathing (SDB) is a treatable risk factor that has been seen to occur concurrently, and is known to propagate mortality and morbidity in a number of cardiovascular disease states including heart failure, and indeed hypertrophic cardiomyopathy. In this review, we summarize past studies that explored the simultaneous occurrence of HCM and SDB, and the pathophysiology of SDB in relation to heart failure, arrhythmias, cardiac ischemia and pulmonary hypertension in HCM. The current therapeutic modalities, with the effect of obstructive sleep apnea (OSA) treatment on HCM, are then discussed along with potential future directions.

AVAPS-AE versus ST mode: A randomized controlled trial in patients with obesity hypoventilation syndrome

BACKGROUND AND OBJECTIVE

Average volume-assured pressure support-automated expiratory positive airway pressure (AVAPS-AE) combines an automated positive expiratory pressure to maintain upper airway patency to an automated pressure support with a targeted tidal volume. The aim of this study was to compare the effects of 2-month AVAPS-AE ventilation versus pressure support (ST) ventilation on objective sleep quality in stable patients with OHS. Secondary outcomes included arterial blood gases, health-related quality of life, daytime sleepiness, subjective sleep quality and compliance to NIV.

METHODS

This is a prospective multicentric randomized controlled trial. Consecutive OHS patients included had daytime P_a CO₂  > 6 kPa, BMI ≥ 30 kg/m² , clinical stability for more than 2 weeks and were naive from home NIV. PSG were analysed centrally by two independent experts. Primary endpoint was sleep quality improvement at 2 months.

RESULTS

Among 69 trial patients, 60 patients had successful NIV setup. Baseline and follow-up PSG were available for 26 patients randomized in the ST group and 30 in the AVAPS-AE group. At baseline, P_a CO₂ was 6.94 ± 0.71 kPa in the ST group and 6.61 ± 0.71 in the AVAPS-AE group (P = 0.032). No significant between-group difference was observed for objective sleep quality indices. Improvement in P_a CO₂ was similar between groups with a mean reduction of -0.87 kPa (95% CI: -1.12 to -0.46) in the ST group versus -0.87 kPa (95% CI: -1.14 to -0.50) in the AVAPS-AE group (P = 0.984). Mean NIV use was 6.2 h per night in both groups (P = 0.93). NIV setup duration was shorter in the AVAPS-AE group (P = 0.012).

CONCLUSION

AVAPS-AE and ST ventilation for 2 months had similar impact on sleep quality and gas exchange.

Association of Obstructive Sleep Apnea With Cardiovascular Outcomes in Patients With Acute Coronary Syndrome

Background

The prognostic significance of obstructive sleep apnea (OSA) in patients with acute coronary syndrome (ACS) in the contemporary era is unclear. We performed a large, prospective cohort study and did a landmark analysis to delineate the association of OSA with subsequent cardiovascular events after ACS onset.

Methods and Results

Between June 2015 and May 2017, consecutive eligible patients admitted for ACS underwent cardiorespiratory polygraphy during hospitalization. OSA was defined as an apnea‐hypopnea index ≥15 events·h⁻¹. The primary end point was major adverse cardiovascular and cerebrovascular event (MACCE), including cardiovascular death, myocardial infarction, stroke, ischemia‐driven revascularization, or hospitalization for unstable angina or heart failure. OSA was present in 403 of 804 (50.1%) patients. During median follow‐up of 1 year, cumulative incidence of MACCE was significantly higher in the OSA group than in the non‐OSA group (log‐rank, P=0.041). Multivariate analysis showed that OSA was nominally associated with incidence of MACCE (adjusted hazard ratio, 1.55; 95% CI, 0.94–2.57; P=0.085). In the landmark analysis, patients with OSA had 3.9 times the risk of incurring a MACCE after 1 year (adjusted hazard ratio, 3.87; 95% CI, 1.20–12.46; P=0.023), but no increased risk was found within 1‐year follow‐up (adjusted hazard ratio, 1.18; 95% CI, 0.67–2.09; P=0.575). No significant differences were found in the incidence of cardiovascular death, myocardial infarction, and ischemia‐driven revascularization, except for a higher rate of hospitalization for unstable angina in the OSA group than in the non‐OSA group (adjusted hazard ratio, 2.10; 95% CI, 1.09–4.05; P=0.027).

Conclusions

There was no independent correlation between OSA and 1‐year MACCE after ACS. The increased risk associated with OSA was only observed after 1‐year follow‐up. Efficacy of OSA treatment as secondary prevention after ACS requires further investigation.

Obstructive sleep apnoea in acute coronary syndrome

Obstructive sleep apnoea (OSA) syndrome affects about 13% of the male and 7–9% of the female population. Hypoxia, oxidative stress and systemic inflammation link OSA and cardiovascular and metabolic consequences, including coronary artery disease. Current research has identified several clinical phenotypes, and the combination of breathing disturbances during sleep, systemic effects and end-organ damage might help to develop personalised therapeutic approaches. It is unclear whether OSA is a risk factor for acute coronary syndrome (ACS) and might affect its outcome. On the one hand, OSA in patients with ACS may worsen prognosis; on the other hand, OSA-related hypoxaemia could favour the development of coronary collaterals, thereby exerting a protective effect. It is unknown whether positive airway pressure treatment may influence adverse events and consequences of ACS. In non-sleepy patients with OSA and stable coronary artery disease, randomised controlled trials failed to show that continuous positive airway pressure (CPAP) treatment protected against cardiovascular events. Conversely, uncontrolled studies suggested positive effects of CPAP treatment in such patients. Fewer data are available in subjects with ACS and OSA, and results of randomised controlled studies on the effects of CPAP are expected shortly. Meanwhile, the search for reliable markers of risk continues. Recent studies suggest that daytime sleepiness may indicate a more severe OSA phenotype with regard to cardiovascular risk. Finally, some studies suggest sex-related differences. The picture is still incomplete, and the potential role of OSA in patients with ACS awaits confirmation, as well as clear definition of subgroups with different degrees of risk.

Evidence suggests a high prevalence of OSA in ACS. While some studies suggest hypoxia may have a protective effect, the majority show increased adverse cardiac outcomes. Treatment effectiveness on ACS outcome crucially depends on patients' adherence.http://bit.ly/2Id97ec

The beneficial effect of weight reduction on adverse cardiovascular outcomes following bariatric surgery is attenuated in patients with obstructive sleep apnea

Weight loss after bariatric surgery is associated with reduction in adverse cardiovascular outcomes; however, the impact of obstructive sleep apnea (OSA) on reduction of cardiovascular outcomes after bariatric surgery in morbidly obese patients is not known. We retrospectively assessed differences in cardiovascular events after laparoscopic adjustable gastric banding (LAGB)-induced weight loss in patients with and without OSA before and after propensity score matching for age, sex, body mass index (BMI), and major comorbidities between the two groups and determined predictors of poor outcomes. OSA was present in 222 out of 830 patients (27 per cent) who underwent LAGB between 2001 and 2011. Despite a similar reduction in BMI (20.0 and 20.8 per cent), a significantly higher percentage of cardiovascular events were observed in patients with than without OSA (35.6 vs 6.9 per cent; p < 0.001) at 3 years (mean follow-up 6.0 ± 3.2; range: 0.5 to 13 years). The differences in the cumulative endpoint of new onset stroke, heart failure, myocardial infarction, venous thrombosis, and pulmonary embolism between the OSA and non-OSA groups were maintained after propensity matching. Patients with OSA treated with continuous positive airway pressure (CPAP) during sleep [n = 66] had lower cardiovascular event rates at 30 months compared with those not treated (p < 0.041). OSA (hazard ratio: 6.92, 95% CI: 3.39-14.13, p < 0.001) remained an independent predictor of cardiovascular events after multivariate analysis. Thus, patients with OSA, despite a similar initial weight loss after LAGB, had a higher incidence of cardiovascular events compared with a propensity-matched group without OSA. Treatment with CPAP appears to reduce such events.

Obstructive sleep apnoea and comorbidity - an overview of the association and impact of continuous positive airway pressure therapy

INTRODUCTION

Obstructive sleep apnoea (OSA) is highly prevalent and there is considerable evidence supporting an independent association with a wide range of co-morbidities including cardiovascular, endocrine and metabolic, neuropsychiatric, pulmonary, and renal. Areas covered: A PubMed search of all the recent literature relating to OSA and co-morbidities was undertaken to critically evaluate the potential relationships and possible benefit of continuous positive airway pressure (CPAP) therapy. Expert commentary: The evidence supporting an independent association is stronger for some co-morbidities than others and in cardiovascular diseases is strongest for hypertension and atrial fibrillation. Potential mechanisms include intermittent hypoxia, fluctuating intrathoracic pressure, and recurring micro-arousals that trigger cell and molecular consequences including sympathetic excitation, systemic inflammation and oxidative stress, in addition to metabolic and endothelial dysfunction. Different mechanisms may predominate in individual co-morbidities. Recent long term randomised controlled trials have cast doubt on benefits to co-morbidities from CPAP therapy of OSA, especially where co-morbidities are already established. However, benefits may result in patients who are compliant with therapy and further research is required to clearly establish the role of OSA therapy in both primary and secondary prevention of co-morbidities.

The epidemiology of obstructive sleep apnoea and cardiovascular disease

Obstructive sleep apnoea, the most common form of sleep-disordered breathing, is highly prevalent in patients with cardiovascular disease. The last 30 years has seen a plethora of large scale epidemiological studies investigating the relationship between sleep apnoea and cardiovascular outcomes. This review highlights the key epidemiological studies addressing the links between sleep apnoea and hypertension, cardiac arrhythmias, cerebrovascular disease, coronary artery disease, heart failure and pulmonary hypertension, with a particular focus on some of the most recent reports.

Obstructive sleep apnoea and coronary artery disease

Obstructive sleep apnoea (OSA) is a highly prevalent disorder, which causes significant nocturnal and daytime symptoms, reduced quality of life, and impaired functional capacity. Importantly, however, OSA also appears to predispose to the development of a number of cardiovascular and metabolic diseases, including diabetes, hypertension, and stroke. In this review we explore its relationship with coronary artery disease (CAD), discussing mechanisms whereby it may promote the development of atherosclerosis, evidence of its effect on CAD incidence and outcomes, and coronary imaging studies in subjects with OSA. Finally, we shall evaluate the current evidence regarding the impact of continuous positive airway pressure therapy on CAD outcomes in OSA patients.

Sleep Study and Oximetry Parameters for Predicting Postoperative Complications in Patients With OSA

In the surgical setting, OSA is associated with an increased risk of postoperative complications. At present, risk stratification using OSA-associated parameters derived from polysomnography (PSG) or overnight oximetry to predict postoperative complications has not been established. The objective of this narrative review is to evaluate the literature to determine the association between parameters extracted from in-laboratory PSG, portable PSG, or overnight oximetry and postoperative adverse events. We obtained pertinent articles from Ovid MEDLINE, Ovid MEDLINE In-Process & Other Non-Indexed Citations, and Embase (2008 to December 2017). The search included studies with adult patients undergoing surgery who had OSA diagnosed with portable PSG, in-laboratory PSG, or overnight oximetry that reported on specific sleep parameters and at least one adverse outcome. The search was restricted to English-language articles. The search yielded 1,810 articles, of which 21 were included in the review. Preoperative apnea-hypopnea index (AHI) and measurements of nocturnal hypoxemia such as oxygen desaturation index (ODI), cumulative sleep time percentage with oxyhemoglobin saturation (Spo₂) < 90% (CT90), minimum Spo₂, mean Spo₂, and longest apnea duration were associated with postoperative complications. OSA is associated with postoperative complications in the population undergoing surgery. Clinically and statistically significant associations between AHI and postoperative adverse events exists. Complications may be more likely to occur in the category of moderate to severe OSA (AHI ≥ 15). Other parameters from PSG or overnight oximetry such as ODI, CT90, mean and minimal Spo₂, and longest apnea duration can be associated with postoperative complications and may provide additional value in risk stratification and minimization.