Right Ventricular Remodeling and Dysfunction in Obstructive Sleep Apnea: A Systematic Review of the Literature and Meta-Analysis

Links Between Obstructive Sleep Apnea and Myocardial Blood Flow Changes Impacting Adverse Cardiovascular Disease-related Outcomes

PURPOSE OF REVIEW

Recent studies have demonstrated an association between obstructive sleep apnea (OSA) and abnormal myocardial blood flow (MBF), myocardial flow reserve (MFR), and coronary microvascular dysfunction (CMD). Here, we review the evidence and describe the potential underlying mechanisms linking OSA to abnormal MBF. Examining relevant studies, we assess the impact of OSA-specific therapy, such as continuous positive airway pressure (CPAP), on MBF.

RECENT FINDINGS

Recent studies suggest an association between moderate to severe OSA and abnormal MBF/MFR. OSA promotes functional and structural abnormalities of the coronary microcirculation. OSA also promotes the uncoupling of MBF to cardiac work. In a handful of studies with small sample sizes, CPAP therapy improved MBF/MFR. Moderate to severe OSA is associated with abnormal MFR, suggesting an association with CMD. Evidence suggests that CPAP therapy improves MBF. Future studies must determine the clinical impact of improved MBF with CPAP.

Relationships between Heart Chamber Morphology or Function and Respiratory Parameters in Patients with HFrEF and Various Types of Sleep-Disordered Breathing

Sleep-disordered breathing (SDB), i.e., central sleep apnea (CSA) and obstructive sleep apnea (OSA), affects the prognosis of patients with heart failure with reduced ejection fraction (HFrEF). The study assessed the relationships between heart chamber size or function and respiratory parameters in patients with HFrEF and various types of SDB. The 84 participants were patients aged 68.3 ± 8.4 years (80% men) with an average left ventricular ejection fraction (LVEF) of 25.5 ± 6.85% who qualified for cardioverter-defibrillator implantation with or without cardiac resynchronization therapy. SDB, defined by an apnea-hypopnea index (AHI) ≥ five events/hour, was diagnosed in 76 patients (90.5%); SDB was severe in 31 (36.9%), moderate in 26 (31.0%), and mild in 19 (22.6%). CSA was the most common type of SDB (64 patients, 76.2%). A direct proportional relationship existed only in the CSA group between LVEF or stroke volume (SV) and AHI (p = 0.02 and p = 0.07), and between LVEF or SV and the percentage of total sleep time spent with hemoglobin oxygen saturation < 90% (p = 0.06 and p = 0.07). In contrast, the OSA group was the only group in which right ventricle size showed a positive relationship with AHI (for basal linear dimension [RVD1] p = 0.06), mean duration of the respiratory event (for RVD1 p = 0.03, for proximal outflow diameter [RVOT proximal] p = 0.009), and maximum duration of respiratory event (for RVD1 p = 0.049, for RVOT proximal p = 0.006). We concluded that in HFrEF patients, SDB severity is related to LV systolic function and SV only in CSA, whereas RV size correlates primarily with apnea/hypopnea episode duration in OSA.

The causality between obstructive sleep apnea and ventricular structure and function: a bidirectional Mendelian randomization study

Background: Multiple observational studies have discovered a substantial link between obstructive sleep apnea (OSA) and ventricular dysfunction. However, conventional observational studies are vulnerable to causal reversal and confounding, making it challenging to infer the causes of effects and their direction. Methods: With the help of a bidirectional, two-sample Mendelian randomization (MR) study, we assessed the potential causality between OSA and left and right ventricular (LV, RV) structure and function. We conducted our analysis utilizing summary data from genome-wide association studies of OSA (16,761 cases and 201,194 controls) in the FinnGen Study, as well as LV (36,041 participants) and RV (29,506 participants) in the UK Biobank cardiovascular magnetic resonance research. The inverse variance weighted (IVW) was selected as the main strategy, with the MR-Egger and weighted median methods serving as supplements. Other methods were employed as sensitivity analysis tools to look at heterogeneity and pleiotropy, including MR-Egger intercept, Cochran Q statistic, MR-PRESSO, and leave-one-out analysis. Results: In the primary IVW analysis, genetically predicted OSA was strongly causative on LV end-diastolic volume (β = 0.114, 95% CI = 0.034-0.194, p = 0.006) and LV stroke volume (β = 0.111, 95% CI = 0.031-0.191, p = 0.007), and genetically predicted LV ejection fraction was linked to an increased risk of OSA (OR = 1.161, 95% CI = 1.029-1.309, p = 0.015). However, there was no connection found between OSA and any RV parameters. Conclusion: Our genetic analysis raises a potential causative link between OSA and ventricular structure and function, which may improve the knowledge of OSA as a risk factor for cardiovascular disease by demonstrating a direct impact on cardiac structure and function.

Correlation between obstructive sleep apnea and ventricular function: a cross-sectional hospital-based study

BACKGROUND

Obstructive sleep apnoea (OSA) is a major cause of cardiovascular morbidity and mortality worldwide. Previous studies showed high prevalence of OSA in heart failure. We aimed to evaluate the association of OSA with cardiac dysfunction and the importance of myocardial performance index (Tei) in identifying cardiac dysfunction.

METHODS

Participants with OSA and sinus rhythm were included, while participants with arrhythmia, debilitating disease, or significant valvular heart disease were excluded. Thirty participants were enrolled, consecutively allocated in a single group, and underwent nocturnal polysomnography, electrocardiogram, and transthoracic echocardiography.

RESULTS

The prevalence of hypertension, diabetes, and smoking in the study population was 50%, 30%, and 23.3%, respectively. The mean body mass index and apnoea-hypopnoea index (AHI) of the study population was 40.11 ± 7.5 kg/m2 and22.12 ± 13.54 events/h, respectively. There were statistically significant differences between mild, moderate, and severe OSA regarding the left ventricular end diastolic diameter, left ventricular end systolic diameter, ejection fraction, and fractional shortening (p = 0.006, p = 0.002, p = 0.014 and p = 0.011),respectively. There were statistically significant regular positive correlations between the AHI and the right and left Tei (r = 0.447, p = 0.001 and r = 0.391, p = 0.003),respectively.

CONCLUSIONS

The prevalence of OSA was more in patients with comorbidities especially hypertension and diabetes. OSA was significantly associated with ventricular remodelling and cardiac dysfunction. A significant regular positive correlation was observed between the severity of OSA and worsening cardiac function as measured by Tei. Echocardiographic evaluation of the right and left ventricles and the right and left Tei could be considered as potentially valid, reproducible, and clinically applicable non-invasive methods for estimation of ventricular global function in patients with OSA.

Role of TRPC3 in Right Ventricular Dilatation under Chronic Intermittent Hypoxia in 129/SvEv Mice

Patients with obstructive sleep apnea (OSA) exhibit a high prevalence of pulmonary hypertension and right ventricular (RV) hypertrophy. However, the exact molecule responsible for the pathogenesis remains unknown. Given the resistance to RV dilation observed in transient receptor potential canonical 3(Trpc3)^-/- mice during a pulmonary hypertension model induced by phenylephrine (PE), we hypothesized that TRPC3 also plays a role in chronic intermittent hypoxia (CIH) conditions, which lead to RV dilation and dysfunction. To test this, we established an OSA mouse model using 8- to 12-week-old 129/SvEv wild-type and Trpc3^-/- mice in a customized breeding chamber that simulated sleep and oxygen cycles. Functional parameters of the RV were evaluated through analysis of cardiac cine magnetic resonance images, while histopathological examinations were conducted on cardiomyocytes and pulmonary vessels. Following exposure to 4 weeks of CIH, Trpc3^-/- mice exhibited significant RV dysfunction, characterized by decreased ejection fraction, increased end-diastole RV wall thickness, and elevated expression of pathological cardiac markers. In addition, reactive oxygen species (ROS) signaling and the endothelin system were markedly increased solely in the hearts of CIH-exposed Trpc3^-/- mice. Notably, no significant differences in pulmonary vessel thickness or the endothelin system were observed in the lungs of wild-type (WT) and Trpc3^-/- mice subjected to 4 weeks of CIH. In conclusion, our findings suggest that TRPC3 serves as a regulator of RV resistance in response to pressure from the pulmonary vasculature, as evidenced by the high susceptibility to RV dilation in Trpc3^-/- mice without notable changes in pulmonary vasculature under CIH conditions.

Obstructive Sleep Apnea and Right Ventricular Remodeling: Do We Have All the Answers?

Obstructive sleep apnea (OSA) syndrome is a very important sleep-related breathing disorder related to increased cardiovascular and overall morbidity and mortality. It is associated with multisystemic target organ damage due to micro- and macrovascular changes, resulting in carotid and coronary atherosclerosis, increased arterial stiffness, retinal damage, microalbuminuria, and cardiac remodeling. The latter consists of left ventricular (LV) hypertrophy, as well as diastolic and systolic dysfunction. The increasing burden of evidence shows that OSA also induces right ventricular (RV) remodeling that is more difficult to diagnose, but may also contribute to cardiovascular morbidity and mortality in these patients. Conventional echocardiographic parameters for assessment of RV systolic and diastolic functions are often not sensitive enough to detect subclinical and subtle changes in the RV function. Data published over last decade showed that the RV function, particularly systolic, is impaired in OSA patients and related with its severity. However, the introduction of speckle tracking echocardiography and the particularly longitudinal strain enabled the earlier detection of functional and mechanical changes even when conventional echocardiographic parameters of RV systolic function remained unchanged. The 3D echocardiography provided the possibility to evaluate the entire RV, with its unique shape, and determine 3D RV ejection fraction, which is comparable with results obtained by cardiac magnetic resonance. The use of this modality also provided a new insight into RV systolic (dys)function in OSA patients. In addition to weight loss, which has been proven very helpful in OSA patients, the only approved therapeutic approach is continuous positive airway pressure (CPAP) therapy. It is very important to assess if this therapy induces any improvement in cardiac structure and function. Limited data on this topic show that RV longitudinal strain is a more sensitive parameter rather than other conventional RV indexes in the detection of improvement in RV systolic function and mechanics. The aim of this review article is to summarize the current understanding of RV structural, functional, and mechanical changes in patients with OSA. Furthermore, we sought to provide the current knowledge regarding the effect of CPAP therapy on RV reverse remodeling in OSA patients.

Right ventricular responses to CPAP therapy in obstructive sleep apnea: CMR analysis of the MOSAIC randomized trial

Effects of continuous positive airway pressure (CPAP) on right ventricular (RV) function in patients with untreated mild-to-moderate obstructive sleep apnea (OSA) are unclear. In this exploratory analysis of cardiac magnetic resonance (CMR)-derived indices of RV function in patients with minimally symptomatic OSA from the MOSAIC randomized control trial we found no effect of CPAP on RV CMR parameters. In those with lower RV ejection fraction and higher RV end-diastolic volume (EDV) at baseline, CPAP treatment appeared to improve RV function with a significant reduction in both RV EDV and RV end-systolic volume although between-group effects were not observed. These data suggest potential merit in a larger randomized study of CPAP in patients with mild-to-moderate OSA and a greater breadth of RV dysfunction.

Changes in Left Heart Geometry, Function, and Blood Serum Biomarkers in Patients with Obstructive Sleep Apnea after Treatment with Continuous Positive Airway Pressure

Background: Cardiovascular remodeling is essential in patients with obstructive sleep apnea (OSA), and continuous positive airway pressure (CPAP) therapy could improve these processes. Two-dimensional (2D) speckle-tracking (ST) echocardiography is a useful method for subclinical biventricular dysfunction diagnosis and thus might help as an earlier treatment for OSA patients. It is still not clear which blood serum biomarkers could be used to assess CPAP treatment efficacy. Objectives: To evaluate left heart geometry, function, deformation parameters, and blood serum biomarker (galectin-3, sST2, endothelin-1) levels in patients with OSA, as well as to assess changes after short-term CPAP treatment. Materials and Methods: Thirty-four patients diagnosed with moderate or severe OSA, as well as thirteen patients as a control group, were included in the study. All the subjects were obese (body mass index (BMI) > 30 kg/m2). Transthoracic 2D ST echocardiography was performed before and after 3 months of treatment with CPAP; for the control group, at baseline only. Peripheral blood samples for the testing of biomarkers were collected at the time of study enrolment before the initiation of CPAP therapy and after 3 months of CPAP treatment (blood samples were taken just for OSA group patients). Results: The left ventricle (LV) end-diastolic diameter and volume, as well as LV ejection fraction (EF), did not differ between groups, but an increased LV end-systolic volume and a reduced LV global longitudinal strain (GLS) were found in the OSA group patients (p = 0.015 and p = 0.035, respectively). Indexed by height, higher LV MMi in OSA patients (p = 0.007) and a higher prevalence of LV diastolic dysfunction (p = 0.023) were found in this group of patients. Although left atrium (LA) volume did not differ between groups, OSA group patients had significantly lower LA reservoir strain (p < 0.001). Conventional RV longitudinal and global function parameters (S′, fractional area change (FAC)) did not differ between groups; however, RV GLS was reduced in OSA patients (p = 0.026). OSA patients had a significantly higher right atrium (RA) diameter and mean pulmonary artery pressure (PAP) (p < 0.05). Galectin-3 and sST2 concentrations significantly decreased after 3 months of CPAP treatment. Conclusions: OSA is associated with the left heart remodeling process—increased LV myocardial mass index, LV diastolic dysfunction, reduced LV and RV longitudinal strain, and reduced LA reservoir function. A short-term, 3-months CPAP treatment improves LV global longitudinal strain and LA reservoir function and positively affects blood serum biomarkers. This new indexing system for LV myocardial mass by height helps to identify myocardial structural changes in obese patients with OSA.

Predictive value of incidental right ventricular abnormalities identified on SPECT for mortality and pulmonary hypertension

BACKGROUND

The clinical significance of incidentally found RV abnormalities on low-risk SPECT studies is not well-defined. The objective of this study was to determine the predictive value of incidental right ventricular (RV) abnormalities identified on single photon emission computed tomography (SPECT) scans for mortality and pulmonary hypertension (PH).

METHODS

We retrospectively analyzed all low-risk SPECT studies in patients without known coronary artery or pulmonary vascular disease, performed at our institution, from 2007-2020. Adjusted Cox proportional hazards models were used to evaluate the association between incidental RV abnormalities on low-risk SPECT studies and outcomes.

RESULTS

Of the 4761 patients included in the analysis, mortality events were present in 494, and echocardiographic PH was present in 619. Incidental RV abnormalities on low-risk SPECT studies were significantly and independently associated with all-cause mortality (HR = 1.41, CI [1.07-1.86], P = 0.0152) and echocardiographic PH (HR = 2.06, CI [1.64-2.60], P < 0.0001).

CONCLUSIONS

These data suggest incidental RV abnormalities found on low-risk SPECT imaging studies are significantly and independently associated with increased mortality and risk of developing echocardiographic PH, and could identify high-risk patients for closer monitoring and additional diagnostic testing.

Obstructive Sleep Apnea and Cardiovascular Risk: The Role of Dyslipidemia, Inflammation, and Obesity

Introduction: The present study aimed to establish the role of lipid abnormalities and inflammatory markers for developing cardiovascular risk, as well as to address the importance of obesity as a common comorbidity in patients with obstructive sleep apnea (OSA).

Methods: The study was conducted as a prospective cohort study including 120 patients with newly diagnosed OSA between 2019 and 2020, at University Clinical Hospital Center “Bezanijska kosa”, Belgrade, Serbia. The diagnosis was established by polysomnography. In all patients, sociodemographic data, respiratory, lipid, and inflammatory parameters were collected and complete echocardiographic study and 24-h blood pressure monitoring were performed.

Results: The mean patient age was 55.7 ± 13.8 years. Study population was mostly male (70.0%) and obese (56.7%). At least 30 apneas or hypopneas per hour were present in 39.0% of patients. A strong positive correlation was found between OSA severity and BMI (r = 0.562, p < 0.001), both associated with lipid, inflammatory and respiratory parameters, and cardiovascular profile of patients with OSA (p < 0.05 for all). Echocardiographic study and 24-h blood pressure monitoring parameters were in turn correlated with lipid and inflammatory markers (p < 0.05 for all).

Conclusion: The results of this study support the important role of dyslipidemia and inflammation, as well as coexistence of obesity in the pathogenesis of numerous conditions linked with an increased risk of cardiovascular morbidity and mortality in patients with OSA.

Does Sleep Position Influence Sleep-Disordered Breathing in Infants With Cleft Palate: A Feasibility Study?

OBJECTIVE

Cleft palate (CP) can affect breathing, leading to sleep-disordered breathing (SDB). Sleep position can affect SDB, but the optimum sleep position for infants with CP is unknown. We aimed to determine the design of a pragmatic study to investigate the effect of the 2 routinely advised sleep positions in infants with CP on oxygen saturations.

DESIGN

A multicentered observational cohort.

SETTING

Four UK-based cleft centers, 2 advising supine- and 2 side-lying sleep positions for infants with CP.

PARTICIPANTS

Infants with isolated CP born July 1, 2015, and December 31, 2016. Of 48 eligible infants, 30 consented (17 side-lying; 13 supine).

INTERVENTIONS

Oxygen saturation (SpO2) and end-tidal carbon dioxide (ETCO2) home monitoring at age 1 and 3 months. Qualitative interviews of parents.

OUTCOME MEASURES

Willingness to participate, recruitment, retention, and acceptability/success (>90 minutes recording) of SpO2 and ETCO2 monitoring.

RESULTS

SpO2 recordings were obtained during 50 sleep sessions on 24 babies (13 side-lying) at 1 month (34 sessions >90 minutes) and 50 sessions on 19 babies (10 side-lying) at 3 months (27 sessions >90 minutes). The ETCO2 monitoring was only achieved in 12 sessions at 1 month and 6 at 3 months; only 1 was >90 minutes long. The ETCO2 monitoring was reported by the majority as unacceptable. Parents consistently reported the topic of sleep position in CP to be of importance.

CONCLUSIONS

This study has demonstrated that it is feasible to perform domiciliary oxygen saturation studies in a research setting and has suggested that there may be a difference in the effects of sleep position that requires further investigation. We propose a study with randomization is indicated, comparing side-lying with supine-lying sleep position, representing an important step toward better understanding of SDB in infants with CP.

Continuous positive airway pressure treatment in sleep apnea: patient compliance and impact on the right heart

Obstructive sleep apnea syndrome (OSAS) is considered to be an important predisposing factor for cardiovascular diseases. The main objective of this study was to investigate the impact of CPAP treatment on cardiac structure and function and to assess patient compliance over a long-term course of CPAP treatment. A total of 50 patients diagnosed with moderate-to-severe OSAS based on overnight study, without relevant concomitant diseases were enrolled. Patient compliance, along with echocardiographic and CPAP parameters, was assessed. The average time to follow-up was 38 ± 4.2 months. An increase in tricuspid annular plane systolic excursion (TAPSE) (22.1 ± 4.3-25.5 ± 4.6 mm, p = 0.005) and peak early systolic tricuspid annular velocity (S') (14 ± 3.2-17.2 ± 5.2 cm/s, p = 0.005) after CPAP treatment was noted. In patients without CPAP, no significant change in right ventricular (RV) contractility was found. There were no significant differences regarding right atrial (RA) and RV diameters, as well as tricuspid regurgitant peak gradient (TRPG) in both groups; however, a predisposition to increased RA size along with RV and tricuspid annulus diameters was revealed. The mean duration of nightly CPAP use was 3 ± 2.3 h/night in all-day analysis and 4.7 ± 2.1 h/night on days with device usage. The non-adherence rate was 57%. The use of effective CPAP therapy may lead to increased RV systolic function in patients with OSAS in long-term observation. However, long-term patient compliance is generally poor. Regardless of CPAP therapy, a gradual increase in heart size is observed.

Predictive echocardiographic factors of severe obstructive sleep apnea

Introduction

obstructive sleep apnea (OSA) is a common chronic pulmonary disease, characterized by repetitive collapse of the upper respiratory airways, leading to oxygen desaturation. This condition is recognized to be associated with cardiovascular disease. Several studies have shown the effects of OSA on both geometry and cardiac function, with conflicting results. We aimed to investigate the relationship between echocardiographic abnormalities and the severity of OSA.

Methods

this is a cross-sectional single center study including patients, without any cardiovascular or pulmonary comorbidities, with polygraphy proven OSA. All participants underwent a detailed transthoracic echocardiography (TTE).

Results

a total of 93 patients were included in the study, with 62.2% (n=56) females. According to the apnea hypopnea index (AHI), patients were divided into two groups: mild to moderate OSA (5≤ AHI< 30/H) and severe OSA (AHI≥ 30/H). There were no differences in baseline characteristics between the two groups. The assessment of echocardiographic parameters demonstrated that severe OSA have a higher left ventricular end-systolic (LVES) (47.6±7.2 VS 46.2±4.7), left ventricular end-diastolic (LVED) (31.3±6.2 VS 28.9±4.5) diameters and interventricular septum (IVS) thickness (12.7±2.4 VS11.7±2.5) diameters rather than mild to moderate OSA without a significant difference between the two groups. Furthermore, severe OSA patients had lower mean value of left ventricular ejection fraction (LVEF) and fractional shortening (FS) equal to 62.1±9.7 and 32.5±6.3 respectively. The difference between the two groups was not statistically significant. However, a significant association was shown between severity of OSA and left ventricular (LV) diastolic dysfunction, right ventricular internal diameter (RVID) and systolic pulmonary artery pressure (sPAP), with p=0.05, p=0.05 and p= 0.03 respectively. The RVID was also independently associated to the severity of the OSA (aOR 1.33, 95%CI: 0.99-1.79; p=0.05).

Conclusion

using bidimensional echocardiography showed a relationship between severe OSA and right ventricular parameters (diastolic dysfunction and RVID) and sPAP.

Assessment of right ventricular remodeling and dysfunction in obstructive sleep apnea syndrome: a prospective monocentric study

BACKGROUND

Obstructive sleep apnea (OSA) is a common sleep-related disorder that has been implicated in many serious cardiovascular diseases including cardiac remodeling and dysfunction. Since most investigations have focused on the left heart, little is known on right ventricular (RV) involvement in OSA. The role of the RV in the management of cardiovascular outcomes has become increasingly recognized. Early detection of subtle signs of RV dysfunction and remodeling in patients with OSA is crucial for optimal medical care.

PURPOSE

We aimed to investigate the effect of OSA and its severity on the RV structure and function using conventional echocardiography.

METHODS

We conducted a cross-sectional analytical study including patients with OSA who did not have heart failure or chronic pulmonary disease comparing them to controls without OSA. All patients underwent respiratory polygraphy at the Pneumology Department and standard echocardiography performed by the same blinded cardiologist at the Cardiology Department of Taher Sfar University Hospital.

RESULTS

A total of 139 patients with OSA and 45 controls were enrolled in the study. Amonth the patients, there were 32% (n = 44) with mild, 20% (n = 28) with moderate, and 48% (n = 67) with severe OSA. Sixty-three percent of the study population were women. The mean age was 54.1 ± 11.0 years. Early RV dilatation was present in the mild disease stage (RVID = 42.0 ± 7.7 mm vs. 32.4 ± 5.5 mm in controls; p < 0.0001) without obvious RVH. The systolic pulmonary artery pressure was significantly higher in patients with OSA (31.2 ± 8.2 vs. 20.9 ± 9.8; p < 0.0001). Tricuspid annular plane systolic excursion was borderline normal and significantly lower in patients with OSA (17.7 ± 4.7 vs. 26.0 ± 5.7, p < 0.0001). In multivariate analysis, an OSA was independently associated with RV remodeling (OR: 0.257, 95% CI [0.114-0.582], p = 0.001) but not with RV dysfunction.

CONCLUSION

OSA was independently associated with structural alterations of RV early in the disease course, suggesting that the reversibility of these deleterious effects requires earlier detection and initiation of treatment.

Cardiovascular Disorders Triggered by Obstructive Sleep Apnea-A Focus on Endothelium and Blood Components

Obstructive sleep apnea (OSA) is known to be an independent cardiovascular risk factor. Among arousal from sleep, increased thoracic pressure and enhanced sympathetic activation, intermittent hypoxia is now considered as one of the most important pathophysiological mechanisms contributing to the development of endothelial dysfunction. Nevertheless, not much is known about blood components, which justifies the current review. This review focuses on molecular mechanisms triggered by sleep apnea. The recurrent periods of hypoxemia followed by reoxygenation promote reactive oxygen species (ROS) overproduction and increase inflammatory response. In this review paper we also intend to summarize the effect of treatment with continuous positive airway pressure (CPAP) on changes in the profile of the endothelial function and its subsequent potential clinical advantage in lowering cardiovascular risk in other comorbidities such as diabetes, atherosclerosis, hypertension, atrial fibrillation. Moreover, this paper is aimed at explaining how the presence of OSA may affect platelet function and exert effects on rheological activity of erythrocytes, which could also be the key to explaining an increased risk of stroke.

An umbrella review of systematic reviews and meta-analyses of observational investigations of obstructive sleep apnea and health outcomes

Purpose

The previous analysis of systematic reviews and meta-analyses have illustrated that obstructive sleep apnea (OSA) is correlated with multiple health outcomes. In the present research, our main aim was to execute an umbrella review to assess the available evidence for the associations between OSA and health outcomes.

Methods

Herein, a meta-analysis of previous observational investigations that have reported associations between OSA and health outcomes in all human populations and settings was performed. We used these studies to execute an umbrella review of available meta-analyses and systematic reviews.

Results

Sixty-six articles comprising 136 unique outcomes were enrolled in this analysis. Of the 136 unique outcomes, 111 unique outcomes had significant associations (p < 0.05). Only 7 outcomes (coronary revascularization after PCI, postoperative respiratory failure, steatosis, alaninetrans aminase (ALT) elevation, metabolic syndrome (MS), psoriasis, and Parkinson’s disease) had a high quality of evidence. Twenty-four outcomes had a moderate quality of evidence, and the remaining 80 outcomes had a weak quality of evidence. Sixty-nine outcomes exhibited significant heterogeneity. Twenty-five outcomes exhibited publication bias. Sixty-three (95%) studies showed critically low methodological quality.

Conclusion

Among the 66 meta-analyses exploring 136 unique outcomes, only 7 statistically significant outcomes were rated as high quality of evidence. OSA may correlate with an increased risk of coronary revascularization after PCI, postoperative respiratory failure, steatosis, ALT elevation, MS, psoriasis, and Parkinson’s disease.

Cardiac function and cognitive function in patients with obstructive sleep apnea

Objectives

This study was designed to evaluate echocardiographic findings in patients with obstructive sleep apnea (OSA) with cognitive impairment and compare it with the control group.

Methods

Sixty-seven OSA patients and 52 group of healthy controls were evaluated prospectively by Mini-Mental State Examination questionnaire and trans-thoracic echocardiography.

Results

The cognitive impairment and diastolic dysfunction were 19.6% (P = .002) and 18.4% (P = .016) more prevalent in OSA group compared to the control group. The mean tricuspid regurgitant gradient, pulmonary artery size, and transmitral A velocity were higher, but mean right ventricular peak systolic velocity, tricuspid annular plane systolic excursion (TAPSE), fractional area change (FAC), transmitral E/A ratio, and annular E’ velocity were lower in the OSA group than the control group. Comparing the patients with and without cognitive disorders, showed significant differences regarding the size of right atrium, TAPSE and FAC (P < .05).

Conclusions

OSA patients need accurate cardiac examinations, early diagnosis, and interventions to prevent the progression of cardiac dysfunction, especially older male patients with higher BMI and impaired cognition. Further studies are needed to determine the exact link between the OSA, obesity, and cardiac physiology.

Targeting subclinical organ damage in obstructive sleep apnea: a narrative review

Subclinical abnormalities in cardiac and vascular structure reflect the adverse effects triggered by a variety of risk factors on the cardiovascular (CV) system thereby representing an intermediate step in the cardiovascular continuum; such alterations are recognized as reliable markers of increased cardiovascular risk in different clinical settings including obstructive sleep apnea (OSA). The mechanisms underlying subclinical organ damage (OD) in the OSA setting are multifactorial. Hypoxemia and hypercapnia, induced by repeated collapses of upper airways, have been suggested to trigger a cascade of events such as activation of the sympathetic tone, renin-angiotensin-aldosterone system leading to endothelial dysfunction, vasoconstriction, myocardial and vascular remodeling, and hypertension. Furthermore, coexisting non-haemodynamic alterations such as increased oxidative stress, release of inflammatory substances, enhanced lipolysis and insulin resistance have been reported to play a role in the pathogenesis of both cardiac and extra-cardiac OD. In this article we reviewed available evidence on the association between OSA and subclinical cardiac (i.e., left and right ventricular hypertrophy, left atrial dilatation) and extra-cardiac organ damage (i.e., carotid atherosclerosis, arterial stiffness, microvascular retinal changes, and microalbuminuria). This association is apparently stronger for cardiac and carotid subclinical damage than for other markers (i.e., arterial stiffness and retinal changes) and mostly evident in the setting of severe OSA.

Narrative review of sleep and pulmonary hypertension

Pulmonary hypertension (PH) is a condition of raised pulmonary artery pressure (PAP), which may be secondary to a number of causes, one of which is sleep disordered breathing (SDB). When PH complicates SDB, it carries a significant burden of morbidity and mortality due to the risk of progression to right ventricular failure over time. This narrative review will cover the definition and classification of PH, and explore the epidemiology of PH in SDB. The mechanisms by which the two conditions are linked will be reviewed. Repetitive hypoxia with or without hypercapnia alongside frequent arousals can result in important metabolic and pulmonary vascular consequences for the left and right heart. MEDLINE was used to search for all relevant articles and abstracts published from January 1960 to October 2019 inclusive (in all languages). Current best practice in the investigation and management of PH complicating SDB will be reviewed. Important diagnostic investigations and when to consider and screen further for PH in patients with SDB will be discussed. Optimal disease management must include control of SDB with therapy. Additional treatment options will be reviewed. Areas for further research will be highlighted.

Pulmonary arterial pressure and nasal obstruction in mouth-breathing children: Similarities between adenotonsillar hypertrophy and allergic rhinitis

BACKGROUND

Upper airway obstruction may cause pulmonary hypertension in childhood. In this study we aimed to identify a possible correlation of systolic pulmonary arterial pressure (SPAP), using Doppler echocardiography, with nasal patency (NP), as measured by rhinomanometry, in mouth-breathing (MB) children with allergic rhinitis (AR) and adenotonsillar hypertrophy (ATH).

METHODS

In this cross-sectional study we evaluated 183 patients, from 2 to 12 years of age, at an MB referral clinic in Brazil, from December 2013 to 2017. We allocated patients to 4 etiology groups: group 1, 60 MBs with ATH; group 2, 47 MBs with AR; group 3, 43 MBs with both ATH and AR; and group 4, 33 nasal breathing control subjects. The ratio of total nasal inspiratory flow (assessed by active anterior rhinomanometry) and expected inspiratory flow adjusted for height determined the percent NP (%NP).

RESULTS

The median %NP was higher in controls than in the MB groups (controls, 114% [79-147%]; ATH: 65% [5-116%]; AR: 57% [23-144%]; ATH and AR: 64% [3-120%]; p < 0.001). Median SPAP was higher in the MB groups than in controls (SPAP: ATH, 26.0 [20.0-35.0] mmHg; AR, 26.0 [22.0-32.0] mmHg; ATH and AR, 26.30 [20.0-34.0] mmHg; control, 22.0 [16.0-30.0] mmHg; p < 0.001). SPAP showed a negative association with %NP (Spearman's rho = -0.24; p < 0.001).

CONCLUSION

Reduced nasal airflow in MB children showed a correlation with higher levels of systolic pulmonary arterial pressure. The AR and ATH groups were similar in nasal obstruction severity and systolic pulmonary arterial pressure level distribution.

Diastolic dysfunction in men with severe obstructive sleep apnea syndrome but without cardiovascular or oxidative stress-related comorbidities

Background:

We aimed to evaluate whether the severity of obstructive sleep apnea syndrome (OSAS) per se affects the prevalence of left ventricular (LV) diastolic dysfunction in patients without comorbidities.

Methods:

A total of 42 patients with first-diagnosed severe OSAS [apnea–hypopnea index (AHI) > 30] and 25 controls (AHI < 5), having been referred for snoring to the Sleep Laboratory Department of our tertiary Hospital, were enrolled in the study. Inclusion criteria were absence of any cardiovascular or oxidative stress-related comorbidities, and age between 20 and 70 years. Clinical, laboratory, echocardiographic, and polysomnographic data were recorded prospectively. Diastolic dysfunction diagnosis and grading was based on 2016 ASE/EACVI recommendations.

Results:

Severe OSAS was associated with significantly increased prevalence and degree of diastolic dysfunction (26/42; 61.9%) compared with controls (7/25; 28%) (p = 0.007). AHI ⩾ 55 (dichotomous value of severe OSAS subset) was also characterized by greater prevalence and degree of diastolic dysfunction compared with 30 < AHI < 55 patients (p = 0.015). In the severe OSAS subset, age >45 years-old, height <1.745 m, body-mass index (BMI) >27.76 kg m⁻², OSAS severity (AHI > 57.35), oxidative stress (overnight reduction of reduced to oxidized glutathione ratio < 18.44%), and BMI/height ratio > 16.155 kg m⁻³ (an index describing ‘dense’, short-heavy patients) presented significant diagnostic utility in identifying diastolic dysfunction in ROC-curve analysis (0.697 ⩾ AUC ⩾ 0.855, 0.001 ⩽ p ⩽ 0.018). In binary logistic regression model, advanced age (OR 1.23, 95% CI 1.025–1.477; p = 0.026) and AHI (OR 1.123, 95% CI 1.007–1.253; p = 0.036) showed independent association with diastolic dysfunction in severe OSAS.

Conclusions:

The present prospective study may suggest that severe OSAS is significantly associated with LV diastolic dysfunction; OSAS clinical severity exerts a positive influence on (and possibly constitutes an independent risk factor of) LV diastolic dysfunction.

The reviews of this paper are available via the supplementary material section.

Nocturnal Hypoxemia Impacts Right Ventricle Diastolic Function in Obstructive Sleep Apnea: A Retrospective Observational Study

Obstructive sleep apnea (OSA), although a growing healthcare problem and documented risk factor for cardiovascular diseases, is still under-diagnosed in cardiac patients. To investigate the correlation between OSA and echocardiographic parameters of right ventricle diastolic (RVD) dysfunction, in particular trans-tricuspid E-wave deceleration time (EDT), we retrospectively analyzed data of 103 pure (comorbidity-free) OSA patients with comprehensive echocardiographic examination (ETT). Apnea/hypopnea index (AHI), oxygen desaturation index (ODI), mean nighttime oxyhemoglobin saturation (SpO2), time elapsed with SpO2 < 90% (T90) and mean peak desaturation of nocturnal events (Mdes, graded as mild, medium or severe) were compared with echocardiographic parameters. We found RVD dysfunction present in 58.3% of patients. Altered EDT correlated significantly with mean SpO2, T90, and Mdes (p < 0.01, all). Nocturnal desaturators had a significantly worse EDT than non-desaturators (p = 0.027) and a higher risk of prolonged EDT (odds ratio, OR = 2.86). EDT differed significantly according to Mdes severity (p = 0.005) with a higher risk of prolonged EDT in medium/severe vs. mild Mdes (OR = 3.44). EDT detected the presence of RVD dysfunction in 58.3% of our pure OSA patients. It correlated poorly with AHI severity but strongly with nocturnal desaturation severity, independently of age. This ETT marker may be useful for deciding appropriate diagnostic and therapeutic strategies.

Impact of obstructive sleep apnea on pulmonary hypertension in patients with chronic obstructive pulmonary disease

Background:

Chronic obstructive pulmonary disease (COPD) and obstructive sleep apnea (OSA) syndrome are highly prevalent respiratory conditions. Their coexistence is referred to as the overlap syndrome. They are both related to pulmonary hypertension (PH) development. This study investigated the effects of OSA on PH in patients with COPD and the associated factors.

Methods:

Consecutive patients with stable COPD were recruited for an observational cross-sectional study from September 2016 to May 2018 at Peking University Third Hospital. In total, 106 patients with COPD were enrolled and performed home portable monitoring and echocardiography. OSA was defined by an apnea hypopnea index (AHI) ≥10 events/h. Based on OSA absence or presence, patients were divided into the COPD with OSA and COPD without OSA groups. Factors affecting pulmonary artery pressure (PAP) and PH were identified using univariate analysis and logistic regression models.

Results:

In the 106 patients with COPD, the mean age was 69.52 years, 91.5% were men, and the mean forced expiratory volume in 1 s (FEV₁) percentage of predicted was 56.15%. Fifty-six (52.8%) patients with COPD were diagnosed with OSA, and 24 (22.6%) patients with COPD were diagnosed as PH. Compared with COPD without OSA group, the median PAP in COPD with severe OSA group increased by 5 mmHg (36.00 [26.00–50.00] mmHg vs. 31.00 [24.00–34.00] mmHg, P = 0.036). COPD with percent of night-time spent with oxygen saturation below 90% (T90) > 10% group had higher PAP than COPD with T90 ≤ 1% group (36.00 [29.00–50.00)] mmHg vs. 29.00 [25.50–34.00] mmHg, F = 7.889, P = 0.007). Univariate analysis revealed age, FEV₁% predicted, T90, and Charlson index had statistically significant effects on PH. Multiple regression analysis showed a significant and independent effect of both FEV₁% predicted (odds ratio [OR] = 3.46; 95% confidence interval [CI]: 1.15–10.46; P = 0.028) and AHI (OR = 3.20; 95% CI: 1.09–19.35; P = 0.034) on PH.

Conclusions:

Patients with COPD with OSA are more susceptible to PH, which is associated with declining lung function and increased severity of OSA. Thus, nocturnal hypoxemia and OSA in elderly patients with COPD should be identified and treated.

Sleep Apnea and Cardiovascular Disease: An Enigmatic Risk Factor

Synchronization of molecular, metabolic, and cardiovascular circadian oscillations is fundamental to human health. Sleep-disordered breathing, which disrupts such temporal congruence, elicits hemodynamic, autonomic, chemical, and inflammatory disturbances with acute and long-term consequences for heart, brain, and circulatory and metabolic function. Sleep apnea afflicts a substantial proportion of adult men and women but is more prevalent in those with established cardiovascular diseases and especially fluid-retaining states. Despite the experimental, epidemiological, observational, and interventional evidence assembled in support of these concepts, this substantial body of work has had relatively modest pragmatic impact, thus far, on the discipline of cardiology. Contemporary estimates of cardiovascular risk still are derived typically from data acquired during wakefulness. The impact of sleep-related breathing disorders rarely is entered into such calculations or integrated into diagnostic disease-specific algorithms or therapeutic recommendations. Reasons for this include absence of apnea-related symptoms in most with cardiovascular disease, impediments to efficient diagnosis at the population level, debate as to target, suboptimal therapies, difficulties mounting large randomized trials of sleep-specific interventions, and the challenging results of those few prospective cardiovascular outcome trials that have been completed and reported. The objectives of this review are to delineate the bidirectional interrelationship between sleep-disordered breathing and cardiovascular disease, consider the findings and implications of observational and randomized trials of treatment, frame the current state of clinical equipoise, identify principal current controversies and potential paths to their resolution, and anticipate future directions.

Temporal shifts in fluid in pulmonary hypertension with and without sleep apnea

Overnight extracellular rostral fluid shifts have been shown to be of importance in patients with fluid-retaining states and are associated with a higher prevalence of sleep apnea. Pulmonary hypertension is frequently associated with right ventricular dysfunction and progressive right ventricular failure, and an increased prevalence of sleep apnea has been described. In light of the importance of fluid shifts in the pathophysiology of sleep apnea, we aimed to explore temporal fluid shifts in patients with pulmonary hypertension with and without sleep apnea. Patients with pulmonary hypertension (WHO Group 1 or 4) had overnight extracellular rostral fluid shift assessment before and a minimum of 3 months after initiation of pulmonary hypertension-specific therapy. Fluid shift measurements of extracellular leg, abdominal, thoracic and neck fluid volumes were performed simultaneously. Twenty-nine patients with pulmonary hypertension (age 55 ± 16 years, 69% female) participated. Sleep apnea was diagnosed in 15 subjects (apnea-hypopnea index 14 [8-27] per hr). There were no significant differences in baseline or overnight leg extracellular rostral fluid, abdominal extracellular rostral fluid, thoracic extracellular rostral fluid or neck extracellular rostral fluid between those with and without sleep apnea. There was a significant inverse correlation between the sleep apnea severity and the overnight change in leg extracellular rostral fluid (r = -0.375, p = 0.049). There were no significant differences detected in overnight extracellular rostral fluid shifts from baseline to follow-up. Treatment-naïve patients with pulmonary hypertension both with and without sleep apnea demonstrate overnight extracellular rostral fluid shifts from the legs into the thorax and neck. Pulmonary hypertension-specific treatment, while significantly improving cardiac haemodynamics, had little impact on nocturnal extracellular rostral fluid shifts or the presence of sleep apnea.