Association between central sleep apnea and left ventricular structure: the Multi-Ethnic Study of Atherosclerosis

Association Between Central Sleep Apnea and Left Atrial Enlargement in Snoring Patients with Preserved Ejection Fraction

Background

Central sleep apnea (CSA) significantly impacts cardiovascular health, linking it to left atrial enlargement, atrial fibrillation, and impaired cardiac function in heart failure patients with reduced ejection fraction (EF). However, the relationship between CSA and left atrial size in individuals with preserved EF remains underexplored.

Objective

This study aims to examine the relationship between left atrial size and CSA in snoring patients with preserved EF.

Methods

An observational study was conducted involving 341 consecutive snoring patients from a cardiology department who underwent overnight polysomnography (PSG) and echocardiography. Patients with EF below 50%, pulmonary diseases or neuromuscular disorders were excluded. CSA was defined as a central apnea-hypopnea index (CAHI) of five or more events per hour. Inverse probability of treatment weighting (IPTW) and logistic regression models were employed to evaluate the relationship between CSA and left atrial size.

Results

Among the 341 patients, 33 (9.68%) were diagnosed with CSA, with a higher prevalence in males (10.0%) than females (8.91%). Left atrial enlargement (LAE) was observed in 172 patients (50.44%), predominantly in females (71.29%). CSA patients demonstrated significantly higher apnea-hypopnea index (AHI) (49.2/h vs 26.75/h, p < 0.01) and oxygen desaturation index (ODI) (44.9 vs 22.85, p < 0.01), alongside more sleep time with oxygen saturation < 90% (6.6% vs 2.35%, p = 0.01). Echocardiographic evaluations revealed that CSA patients had a greater left atrial anterior-posterior diameter(LAD-ap 42.73 ± 13.01 mm vs 38.15 ± 4.58 mm, p < 0.01) and a higher frequency of LAE (69.7% vs 48.38%, p = 0.02). Males with CSA had a significantly increased risk of LAE (OR: 4.54; 95% CI: 1.45-14.2) after IPTW adjustment, with significant associations persisting among those with risk factors such as smoking and dyslipidemia.

Conclusion

This study highlights a significant association between CSA and left atrial enlargement in males with preserved EF, suggesting that CSA may contribute to atrial remodeling even without reduced ejection fraction.

Central sleep apnea and cardiovascular disease state-of-the-art

Central sleep apnea, a rare polysomnographic finding in the general population, is prevalent in certain cardiovascular conditions including systolic and diastolic left ventricular dysfunction, atrial fibrillation, coronary artery disease, carotid artery stenosis, stroke, and use of certain cardiac-related medications. Polysomnographic findings of central sleep apnea with adverse cardiovascular impacts include nocturnal hypoxemia and arousals, which can lead to increased sympathetic activity both at night and in the daytime. Among cardiovascular diseases, central sleep apnea is most prevalent in patients with left ventricular systolic dysfunction; a large study of more than 900 treated patients has shown a dose-dependent relationship between nocturnal desaturation and mortality. Multiple small randomized controlled trials have shown mitigation of sympathetic activity when central sleep apnea is treated with nocturnal oxygen, continuous positive airway pressure, and adaptive servoventilation. However, two early randomized controlled trials with positive airway pressure devices have shown either a neutral effect on survival or excess premature mortality in the active treatment arm, compared to untreated central sleep apnea. In contrast, the results of the most recent trial using an advanced adaptive servoventilation device showed improved quality of life and no signal for mortality suggesting that treatment of central sleep apnea was at least safe. In addition to positive airway pressure devices, multiple medications have been shown to improve central sleep apnea, but no long-term trials of pharmacologic therapy have been published. Currently, phrenic nerve stimulation is approved for the treatment of central sleep apnea, and the results of a randomized controlled trial showed significant improvement in sleep metrics and quality of life.

Implication of sleep apnea for cardiac remodeling in patients with hypertrophic cardiomyopathy

OBJECTIVES

Cardiac remodeling is a life-long process in hypertrophic cardiomyopathy (HCM), and if uncontrolled, would cause substantial morbidity and mortality. Sleep apnea (SA) is a common comorbidity in HCM. This study aimed to investigate the relationship between SA and cardiac remodeling in a large series of patients with HCM.

METHODS

A total of 606 patients with HCM who underwent sleep evaluations at Fuwai Hospital were included. Parameters of cardiac remodeling were evaluated by echocardiographic studies.

RESULTS

SA was present in 363 (59.9%) patients. Left ventricular (LV) end-diastolic diameter (P < 0.001), left atrial (LA) diameter (P = 0.024), ascending aortic diameter (P < 0.001) all increased and maximal end-diastolic wall thickness (P < 0.001) decreased with the severity of SA. After adjustment for sex, age, body mass index, hypertension, hyperlipidemia, diabetes, coronary artery disease and cigarette use, log (apnea-hypopnea index+1) was independently correlated with increasing LV end-diastolic diameter (β = 0.729, P = 0.003) and deceasing maximal end-diastolic wall thickness (β = -0.503, P = 0.009). Log (percentage of total sleep time spent with oxygen saturation<90% + 1) was independently correlated with increasing LV end-diastolic diameter (β = 0.609, P = 0.004) and LA diameter (β = 0.695, P = 0.006). Severity of SA (severe SA with odds ratio, 2.38; 95% CI, 1.20-4.70; P = 0.013), log (apnea-hypopnea index+1) (OR, 1.28; 95% CI, 1.01-1.63; P = 0.045) and log (percentage of total sleep time spent with oxygen saturation<90% + 1) (OR, 1.31; 95% CI, 1.08-1.59; P = 0.006) were also independently associated with LV enlargement.

CONCLUSIONS

Severity of SA is independently associated with cardiac remodeling indicating a trend toward enlarged chamber size and thinned wall. Clinical trials are required to determine whether treatment of SA improves cardiac remodeling and long-term outcomes in patients with HCM.

Obstructive sleep apnoea heterogeneity and cardiovascular disease

Obstructive sleep apnoea (OSA), characterized by recurrent periods of upper airway obstruction and intermittent hypoxaemia, is prevalent in patients with cardiovascular disease (CVD), and is therefore important to consider in the prevention and management of CVD. Observational studies indicate that OSA is a risk factor for incident hypertension, poorly controlled blood pressure, stroke, myocardial infarction, heart failure, cardiac arrhythmias, sudden cardiac death and all-cause death. However, clinical trials have not provided consistent evidence that treatment with continuous positive airway pressure (CPAP) improves cardiovascular outcomes. These overall null findings might be explained by limitations in trial design and low levels of adherence to CPAP. Studies have also been limited by the failure to consider OSA as a heterogeneous disorder that consists of multiple subtypes resulting from variable contributions from anatomical, physiological, inflammatory and obesity-related risk factors, and resulting in different physiological disturbances. Novel markers of sleep apnoea-associated hypoxic burden and cardiac autonomic response have emerged as predictors of OSA-related susceptibility to adverse health outcomes and treatment response. In this Review, we summarize our understanding of the shared risk factors and causal links between OSA and CVD and emerging knowledge on the heterogeneity of OSA. We discuss the varied mechanistic pathways that result in CVD that also vary across subgroups of OSA, as well as the potential role of new biomarkers for CVD risk stratification.

Whole-genome association analyses of sleep-disordered breathing phenotypes in the NHLBI TOPMed program

BACKGROUND

Sleep-disordered breathing is a common disorder associated with significant morbidity. The genetic architecture of sleep-disordered breathing remains poorly understood. Through the NHLBI Trans-Omics for Precision Medicine (TOPMed) program, we performed the first whole-genome sequence analysis of sleep-disordered breathing.

METHODS

The study sample was comprised of 7988 individuals of diverse ancestry. Common-variant and pathway analyses included an additional 13,257 individuals. We examined five complementary traits describing different aspects of sleep-disordered breathing: the apnea-hypopnea index, average oxyhemoglobin desaturation per event, average and minimum oxyhemoglobin saturation across the sleep episode, and the percentage of sleep with oxyhemoglobin saturation < 90%. We adjusted for age, sex, BMI, study, and family structure using MMSKAT and EMMAX mixed linear model approaches. Additional bioinformatics analyses were performed with MetaXcan, GIGSEA, and ReMap.

RESULTS

We identified a multi-ethnic set-based rare-variant association (p = 3.48 × 10-8) on chromosome X with ARMCX3. Additional rare-variant associations include ARMCX3-AS1, MRPS33, and C16orf90. Novel common-variant loci were identified in the NRG1 and SLC45A2 regions, and previously associated loci in the IL18RAP and ATP2B4 regions were associated with novel phenotypes. Transcription factor binding site enrichment identified associations with genes implicated with respiratory and craniofacial traits. Additional analyses identified significantly associated pathways.

CONCLUSIONS

We have identified the first gene-based rare-variant associations with objectively measured sleep-disordered breathing traits. Our results increase the understanding of the genetic architecture of sleep-disordered breathing and highlight associations in genes that modulate lung development, inflammation, respiratory rhythmogenesis, and HIF1A-mediated hypoxic response.

Cognitive and Neuroimaging Correlates of the Insomnia Severity Index in Obstructive Sleep Apnea: A Pilot-Study

We aim to determine the sleep correlates of age-related brain loss in a sample of middle-aged to older males with obstructive sleep apnea (OSA). We recruited consecutive treatment naïve male patients with moderate to severe OSA from January to November of 2019. We excluded participants if they had dementia, stroke or heart disease. We collected demographic variables and vascular risk factors. We also obtained the insomnia severity index, the Epworth sleepiness scale and the Pittsburgh sleep quality index. We also obtained computerized neurocognitive testing with the go-no-go response inhibition test, Stroop interference test, catch game test, staged information processing speed test, verbal memory test and non-verbal memory test. We derived age and education adjusted domain-specific Z-scores for global cognition, memory, attention, processing speed and executive function. We used brain MRI T1-weighted images to derive total hippocampal and gray matter volumes. Partial correlations evaluated associations between variables from sleep questionnaires (e.g., insomnia severity index score), and polysomnographic variables (the apnea-hypopnea index, average oxygen levels during sleep) with cognitive domains and brain volumes. We examined 16 participants with an age range of 40–76 years, 73% Hispanic/Latino. The mean apnea-hypopnea index was 48.9 ± 25.5 and average oxygen saturation during sleep was 91.4% ± 6.9%. Hypertension was seen in 66% and diabetes mellitus in 27%. We found that the insomnia severity index score and average oxygen levels during sleep had the strongest correlations with brain volumes and cognition. These preliminary findings may aid in developing future strategies to improve age-related brain loss in patients with OSA.

Association of Sleep Quality With Greater Left Ventricular Mass in Children Aged 9 to 11 Years

OBJECTIVE

Research has consistently found associations between sleep characteristics and cardiovascular disease risk in children, adolescents, and adults. Although primarily investigated in clinical samples (e.g., in those with sleep disorders), greater left ventricular mass is associated with poor sleep quality in nonclinical adult populations as well; however, this has not been evaluated in children or adolescents. Our study aim was to consider the relationship between objectively measured sleep characteristics and left ventricular mass in children.

METHODS

We assessed sleep and cardiac structure in a biracial sample of 9- to 11-year-old children (n = 176; 41% White, 59% Black; 50% female). Sleep was assessed with actigraphy for five nights. Cardiac dimensions were assessed using echocardiography.

RESULTS

After adjusting for covariates, we found that poor sleep quality was associated with significantly greater left ventricular mass (β = 0.13, t(167) = 2.14, p = .034, Cohen d = 0.16, for activity during sleep; β = 0.15, t(167) = 2.43, p = .016, Cohen d = 0.18, for sleep fragmentation). Other cardiac dimensions (namely, relative wall thickness and right ventricular dimension) were also significantly associated with sleep characteristics. Notably, associations did not differ as a function of sex or race.

CONCLUSIONS

The present findings are novel and unique because no prior reports have systematically documented the association between poor sleep quality with potentially detrimental cardiac remodeling in a nonclinical sample of children. However, the novelty and importance of these findings require additional research for confirmation.

The Effects of Eplerenone on the Circadian Blood Pressure Pattern and Left Ventricular Hypertrophy in Patients with Obstructive Sleep Apnea and Resistant Hypertension-A Randomized, Controlled Trial

The obstructive sleep apnea (OSA) is highly associated with various significant cardiovascular outcomes such as resistant hypertension (RAH). Despite this, as of now the relationship between high night-time blood pressure (BP) and left ventricular hypertrophy (LVH) in patients with OSA and RAH is not fully understood. The aim of this study was to assess the influence of the addition of eplerenone to a standard antihypertensive therapy on parameters of 24-h ambulatory blood pressure measurement (ABPM) as well as on the results of echocardiography and polysomnography in patients with OSA and RAH. The patients were randomly assigned to one of the two study groups: the treatment group, receiving 50 mg/d eplerenone orally for 6 months (n = 51) and the control group, remaining on their standard antihypertensive therapy (n = 51). After that period, a significant reduction in the night-time BP parameters in the treatment group including an increased night blood pressure fall from 4.6 to 8.9% was noted. Additionally, the number of non-dipper patients was reduced by 45.1%. The treatment group also revealed a decrease in left ventricular hypertrophy and in the apnea-hypopnea index (AHI) with a positive correlation being observed between these two parameters. This study is the first to report the improvement of the circadian BP profile and the improvement of the left ventricle geometry in patients with OSA and RAH following the addition of selective mineralocorticoid receptor antagonists to antihypertensive therapy.