Association of obstructive sleep apnoea with subclinical coronary atherosclerosis

Obstructive sleep apnea, coronary calcification and arterial stiffness in patients with diabetic kidney disease

BACKGROUND AND AIMS

Obstructive sleep apnea (OSA) may accelerate arterial calcification, but the relation remains unexplored in diabetic kidney disease (DKD). We examined the associations between OSA, coronary calcification and large artery stiffness in patients with DKD and reduced renal function.

METHODS

Patients with type 2 diabetes, estimated glomerular filtration rate (eGFR) < 60 ml/min/1.73 m2 and urine albumin-creatinine ratio (UACR) > 30 mg/g were tested for OSA quantified by the apnea-hypopnea index (AHI, events/hour). Patients without OSA (AHI< 5) were compared to patients with moderate (AHI 15-29) or severe (AHI ≥30) OSA and underwent computed tomography angiography with coronary Agatston scoring (CAS) to quantify coronary calcification. Arterial stiffness was determined as carotid-femoral pulse wave velocity (PWV).

RESULTS

Among 114 patients with acceptable AHI recordings had 43 no OSA, 33 mild OSA and 38 moderate-severe OSA. Mean age of the 74 patients completing the study was 71.5 ± 9.4 years (73% males), eGFR 32.2 ± 12.3 ml/min/1.73 m2 and UACR 533 (192-1707) mg/g. CAS (ln-transformed) was significantly higher in patients with OSA compared to patients without (6.6 ± 1.7 vs. 5.6 ± 2.4, p = 0.04), and the same was observed for PWV (11.9 ± 2.7 vs. 10.5 ± 2.2 m/s, p = 0.02). In multivariable linear regression analyses adjusted for sex, age, body mass index, UACR, and mean arterial pressure, moderate-severe OSA remained significantly associated with PWV but not with CAS. Dominance analysis revealed OSA as the third and second most important factor relative to CAS and PWV respectively.

CONCLUSIONS

In DKD patients, moderate-severe OSA is a significant predictor of arterial stiffness but is not independently associated with coronary calcification.

The Cardiovascular Impact of Obstructive Sleep Apnea in Women: Current Knowledge and Future Perspectives

Overall, cardiovascular diseases have many sex-related differences in prevalence, clinical presentation, and outcomes. A considerable amount of evidence suggests that obstructive sleep apnea (OSA) increases the risk for several cardiovascular diseases. Only recently, the sex-related differences in cardiovascular outcomes gained interest in the literature. In this review, the authors discuss the current evidence addressing the cardiovascular impact of OSA in women. Particular attention is devoted to hypertension, target-organ damage, heart failure, atrial fibrillation, and cardiovascular events (including mortality). A research agenda is proposed to increase the understanding of the relevance of OSA in women from the Cardiology perspective.

Increased diastolic blood pressure and apnea time contribute to the poor apnea and hypopnea index and life quality of primary snoring: a cohort study combined with external validation

Obstructive sleep apnea hypoventilation syndrome (OSAHS) is a common sleep breathing disorder closely associated with cardiovascular disease. However, the respiratory sleep and related cardiovascular parameters on the apnea and hypopnea index (AHI) and life quality of primary snoring are unclear. We launched a cohort study focused on the association between respiratory sleep and cardiovascular-related parameters and apnea and hypopnea index, incorporating data from 218 patients with primary snoring in our medical center between Jun 1, 2015, and Apr 1, 2016. Thirty patients from Sichuan Cancer Hospital were used for validation. Patients with longer apnea time were more likely to progress to higher AHI (> 30) than controls (OR = 5.66, 95% CI = [2.79, 11.97], p < 0.001). Similarly, if patients have a higher value of diastolic blood pressure, they will also have a higher AHI (> 30) (HR [95% CI] = 3.42 [1.14, 13.65], p = 0.043). According to multivariate analysis, longest apnea time, the mean percentage of SaO2, and neckline length were independent risk factors of overall survival. A predictive model developed based on these factors above yielded a favorable agreement (C-index = 0.872) on the calibration curve. Thirty patients conducted external validation from Sichuan Cancer Hospital, displaying an AUC of 0.833 (0.782-0.884). Increased diastolic blood pressure and apnea time affect AHI level. An AHI prediction model based on these factors above can help clinicians predict the risk of high AHI events.

Association between apnea-hypopnea index and coronary artery calcification: a systematic review and meta-analysis

BACKGROUND

The present study aimed to evaluate the association between presence and severity of obstructive sleep apnoea (OSA) and the presence of subclinical coronary artery disease (CAD) as assessed by coronary calcium score.

METHODS

Medline, Cochrane, and Google Scholar databases were searched. The presence of coronary artery calcification (CAC) and CAC score were assessed.

RESULTS

Irrespective of the cut-off value of apnoea-hypopnea index (AHI) (5 or 15 events/h), patients in the OSA group had higher rate of CAC presence and mean CAC score than those in the control group. Subgroup analyses of patients monitored with home sleep apnoea testing (HSAT) or in-hospital/laboratory polysomnography showed that the OSA group had higher rate of CAC presence and mean CAC score than the control group, except in the comparison of mean CAC score between AHI ≥5 vs. <5 events/h for patients using HSAT, which was not significant. Pair-wise comparison showed that CAC score may increase with increased OSA severity.

CONCLUSIONS

In participants without symptomatic coronary disease, the presence of OSA was associated with the presence and extent of CAC. However, potential confounders such as age, gender, and BMI and the diversity of CAC scores may affect the association.

Is obstructive sleep apnoea associated with hypoxaemia and prolonged ICU stay after type A aortic dissection repair? A retrospective study in Chinese population

Background

Although obstructive sleep apnoea (OSA) is prevalent among patients with aortic dissection, its prognostic impact is not yet determined in patients undergoing major vascular surgery. We aimed to investigate the association of OSA with hypoxaemia and with prolonged intensive care unit (ICU) stay after type A aortic dissection (TAAD) repair.

Methods

This retrospective study continuously enrolled 83 patients who underwent TAAD repair from January 1 to December 31, 2018. OSA was diagnosed by sleep test and defined as an apnoea hypopnea index (AHI) of ≥ 15/h, while an AHI of > 30/h was defined severe OSA. Hypoxaemia was defined as an oxygenation index (OI) of < 200 mmHg. Prolonged ICU stay referred to an ICU stay of > 72 h. Receiver operating characteristic curve analysis was performed to evaluate the predictive value of postoperative OI for prolonged ICU stay. Multivariate logistic regression was performed to assess the association of OSA with hypoxaemia and prolonged ICU stay.

Results

A total of 41 (49.4%) patients were diagnosed with OSA using the sleep test. Hypoxaemia occurred postoperatively in 56 patients (67.5%). Postoperatively hypoxaemia developed mostly in patients with OSA (52.4% vs. 83.0%, p = 0.003), and particularly in those with severe OSA (52.4% vs. 90.5%, p = 0.003). The postoperative OI could fairly predict a prolonged ICU stay (area under the receiver-operating characteristic curve, 0.72; 95% confidence intervals [CI] 0.60–0.84; p = 0.002). Severe OSA was associated with both postoperative hypoxaemia (odds ratio [OR] 6.65; 95% CI 1.56–46.26, p = 0.008) and prolonged ICU stay (OR 5.58; 95% CI 1.54–20.24, p = 0.009).

Conclusions

OSA was common in patients with TAAD. Severe OSA was associated with postoperative hypoxaemia and prolonged ICU stay following TAAD repair.

Obstructive sleep apnea increases the risk of cardiovascular damage: a systematic review and meta-analysis of imaging studies

BACKGROUND

We aimed to perform a systematic review and meta-analysis of the association between obstructive sleep apnea (OSA) and cardiac as well as coronary impairment evaluated using imaging modalities. Finding of this study will provide more robust evidence regarding OSA-induced cardiovascular damage.

METHODS

We systematically searched through PubMed, EMBASE, and Cochrane library databases for relevant literatures on the association between OSA and cardiovascular damage evaluated using imaging modalities, and manually searched the references of selected articles for additional relevant articles. For each clinical parameter relevant to the meta-analysis, we first evaluated the methodological heterogeneity of the relevant studies and thereafter pooled the data together using fixed effect or random effect model. The difference in the relevant indices of cardiovascular damage between OSA patients and controls was evaluated using the standardized mean difference.

RESULTS

Of the 82 articles included in the final systematic analysis, 20 studies explored the association between OSA and coronary atherosclerosis. OSA patients had higher rate of coronary atherosclerosis assessed by coronary artery calcification score and plaque volume. Moreover, the severity of OSA and coronary atherosclerosis displayed a positive correlation. The rest of the studies (n = 62) evaluated cardiac alterations in OSA patients. According to the inclusion and exclusion criteria, 46 studies yielding 3082 OSA patients and 1774 controls were pooled for the meta-analysis. For left cardiac structure and function, OSA patients exhibited significantly wider left atrial diameter; higher left atrium volume index; wider left ventricular end-systolic diameter, left ventricular end-diastolic diameter, and left ventricular mass; higher left ventricular mass index; wider interventricular septum diameter and posterior wall diameter; and higher left ventricular myocardial performance index (all p < 0.05). In addition, compared with controls, left ventricular ejection fraction was significantly decreased in OSA patients (p = 0.001). For right cardiac structure and function, OSA patients displayed a significant increase in right ventricular diameter and right ventricular myocardial performance index (both p < 0.001). Finally, compared with controls, OSA patients displayed significant decrease in tricuspid annular plane systolic excursion and RV fractional area change (p = 0.001).

CONCLUSION

Overall, this systematic review and meta-analysis provides imaging evidence in support that OSA patients are at a higher risk of developing coronary atherosclerosis and display cardiac remodeling and dysfunction.

Integrative analysis of key candidate genes and signaling pathways in acute coronary syndrome related to obstructive sleep apnea by bioinformatics

Although obstructive sleep apnea (OSA) has been clinically reported to be associated with acute coronary syndrome (ACS), the pathogenesis between the two is unclear. Herein, we analyzed and screened out the prospective molecular marker. To explore the candidate genes, as well as signaling cascades involved in ACS related to OSA, we extracted the integrated differentially expressed genes (DEGs) from the intersection of genes from the Gene Expression Omnibus (GEO) cohorts and text mining, followed by enrichment of the matching cell signal cascade through DAVID analysis. Moreover, the MCODE of Cytoscape software was employed to uncover the protein-protein interaction (PPI) network and the matching hub gene. A total of 17 and 56 integrated human DEGs in unstable angina (UA) and myocardial infarction (MI) group associated with OSAs that met the criteria of |log2 fold change (FC)|≥ 1, adjusted P < 0.05, respectively, were uncovered. After PPI network construction, the top five hub genes associated with UA were extracted, including APP, MAPK3, MMP9, CD40 and CD40LG, whereas those associated with MI were PPARG, MAPK1, MMP9, AGT, and TGFB1. The establishment of the aforementioned candidate key genes, as well as the enriched signaling cascades, provides promising molecular marker for OSA-related ACS, which will to provide a certain predictive value for the occurrence of ACS in OSA patients in the future.

Sleep apnea, coronary artery calcium density and cardiovascular events: results from the Multi-Ethnic Study of Atherosclerosis (MESA)

STUDY OBJECTIVES

Evaluate the association between obstructive sleep apnea (OSA), coronary artery calcium (CAC) density, and cardiovascular events in the Multi-Ethnic Study of Atherosclerosis (MESA).

METHODS

We analyzed 1041 participants with non-zero CAC scores who had polysomnography and CAC density data from the fifth examination of MESA. OSA was defined as apnea-hypopnea index [AHI] ≥ 15 events/hour. Multivariable linear regression models were used to evaluate the independent association between OSA and CAC density. Additionally, we evaluated the impact of OSA on associations of CAC measures with incident CVD events by testing for interaction in Cox proportional hazard regression models.

RESULTS

Our analytical sample was 45% female with a mean age of 70.6 +/- 9 years. Of this sample, 36.7% (n=383/1041) had OSA (AHI≥15). OSA was inversely and weakly associated with CAC density (β= -0.09, 95% CI -0.17 to -0.02, p=0.014) and remained significantly associated after controlling for traditional cardiovascular risk factors (β= -0.08, 95% CI -0.16 to 0, p=0.043). However, this inverse association was attenuated after controlling for BMI (β=-0.05, 95% CI -0.13 to 0.02, p=0.174). The mean follow-up period for CVD events was 13.3 +/- 2.8 years. Additionally, exploratory analysis demonstrated that CAC density was independently and inversely associated with CVD events only in the non-OSA subgroup (AHI≤15) (HR 0.509 [CI 0.323 - 0.801], p=0.0035).

CONCLUSIONS

OSA was associated with lower CAC density, but this association was attenuated by BMI. Further, increased CAC density was associated with a reduced risk of CVD events only in individuals within the non-OSA group in exploratory analysis.

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.

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.

Sleep Disordered Breathing and Cardiovascular Diseases

Sleep disordered breathing (SDB), which causes sleep deprivation, intermittent hypoxia, and negative intrathoracic pressure swings, can be accompanied by other harmful pathophysiologies relating to cardiovascular diseases (CVD), including sudden death, atrial fibrillation, stroke, and coronary artery disease leading to heart failure. Continuous positive airway pressure (CPAP) therapy for SDB has been reported to provide favorable effects such as lowered systemic blood pressure and improved endothelial function. However, in recent randomized controlled trials, CPAP has failed to demonstrate its beneficial prognostic impact on the primary or secondary setting of CVD. In this review article, we describe the characteristics of SDB complicated with CVD, the prognostic impacts of SDB in CVD, and the beneficial effects of CPAP on CVD.

Comprehensive coronary plaque assessment in patients with obstructive sleep apnea

Obstructive sleep apnea (OSA) is associated with an increased risk of cardiovascular disease. Previous studies have assessed the relationship between OSA and coronary artery disease (CAD) using coronary artery calcium score (CAC) measurements. However, limited data are available regarding the association of OSA with non-calcified plaque burden. We therefore aimed to assess the relationship between CAD severity as assessed by coronary computed tomography angiography (CTA) and OSA. Forty-one adult subjects (59 ± 9 years, 15 men) underwent a 256-slice coronary CTA, which was followed by a diagnostic attended cardiorespiratory polygraphy (n = 13) or polysomnography (n = 28). Segment involvement score (SIS), segment stenosis score (SSS) and CAC were used to quantify total CAD burden. Correlation analysis was used to assess potential associations between CAD and OSA. Twenty-two patients were diagnosed with OSA. SIS and SSS were elevated in OSA (2.90 ± 2.78 versus 1.79 ± 2.39 and 4.91 ± 5.94 versus 1.79 ± 4.54, OSA versus controls, SIS and SSS respectively, both p < 0.01) and correlated with OSA severity as measured by the apnea-hypopnea index (AHI, r = 0.41 and 0.43, p < 0.01) and oxygen desaturation index (ODI, r = 0.45 and 0.46, p < 0.01). However, no significant correlation was observed between CAC and OSA. Compared to CAC, SIS and SSS provide additional information on coronary plaque burden in OSA, which shows a significant association with OSA.

The Importance of Apneic Events in Obstructive Sleep Apnea Associated with Acute Coronary Syndrome

Background

Obstructive sleep apnea (OSA) is a potential cardiovascular risk factor. However, there is currently no prominent screening strategy for its diagnosis in patients with acute coronary syndrome (ACS). The aim of this study was to establish the impact of apneic events in case of OSA associated with ACS.

Methods

Between January 1st and June 30th, fifty-three subjects with ACS (first acute myocardial infarction) were prospectively evaluated for OSA. Each patient was evaluated by polysomnography (PSG) two months after the ACS.

Results

Mean age of 59±9,6 years, 81,1% males, BMI at 28,5±4,2 kg/m², neck circumference of 42,5±12,6 cm, and waist circumference os 102,5±16,5 cm. The majority of patients (73,6%) had moderate to severe OSA (apnea-hypopnea index (AHI) ≥ 15/h and arousal index ≥ 10/h). We defined the apneic coefficient (AC) as the ratio between apnea index (AI) and AHI. We chose as cut-off the median value of apnea coefficient in our population which was at 37%. The patients with a higher AC (AC ≥ 37% versus AC < 37%) had higher levels of Troponin-I (63,4±63,2 versus 29,7±36,1 ng/mL, p=0,016), higher levels of NT-proBNP (1879,8±2141,8 versus 480±621,3 pg/mL, p=0,001), higher SYNTAX score (15,8±11,5 versus 10,2±5,9, p=0,049), and lower left ventricle ejection fraction (LVEF 53,3±11,4 versus 59,4±6,4%, p=0,023) and were more likely to have a STEMI (21 patients (77,7%) vesus 14 patients (53,8%), p=0,031).

Conclusion

An apneic coefficient (AI/AHI) ≥ 37% is correlated with more severe cardiac impairment, as well as higher hypoxemia and arousal index.

Clinical significance of obstructive sleep apnea in patients with acute coronary syndrome in relation to diabetes status

OBJECTIVE

The prognostic significance of obstructive sleep apnea (OSA) in patients with acute coronary syndrome (ACS) according to diabetes mellitus (DM) status remains unclear. We aimed to elucidate the association of OSA with subsequent cardiovascular events in patients with ACS with or without DM.

RESEARCH DESIGN AND METHODS

In this prospective cohort study, consecutive eligible patients with ACS underwent cardiorespiratory polygraphy between June 2015 and May 2017. OSA was defined as an Apnea Hypopnea Index ≥15 events/hour. The primary 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 804 patients, 248 (30.8%) had DM and 403 (50.1%) had OSA. OSA was associated with 2.5 times the risk of 1 year MACCE in patients with DM (22.3% vs 7.1% in the non-OSA group; adjusted HR (HR)=2.49, 95% CI 1.16 to 5.35, p=0.019), but not in patients without DM (8.5% vs 7.7% in the non-OSA group, adjusted HR=0.94, 95% CI 0.51 to 1.75, p=0.85). Patients with DM without OSA had a similar 1 year MACCE rate as patients without DM. The increased risk of events was predominately isolated to patients with OSA with baseline glucose or hemoglobin A1c levels above the median. Combined OSA and longer hypoxia duration (time with arterial oxygen saturation <90%>22 min) further increased the MACCE rate to 31.0% in patients with DM.

CONCLUSIONS

OSA was associated with increased risk of 1 year MACCE following ACS in patients with DM, but not in non-DM patients. Further trials exploring the efficacy of OSA treatment in high-risk patients with ACS and DM are warranted.

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.

Prevalence and association analysis of obstructive sleep apnea with gender and age differences - Results of SHIP-Trend

Identification of obstructive sleep apnea and risk factors is important for reduction in symptoms and cardiovascular risk, and for improvement of quality of life. The population-based Study of Health in Pomerania investigated risk factors and clinical diseases in a general population of northeast Germany. Additional polysomnography was applied to measure sleep and respiration with the objective of assessing prevalence and risk factors of obstructive sleep apnea in a German cohort. One-thousand, two-hundred and eight people between 20 and 81 years old (54% men, median age 54 years) underwent overnight polysomnography. The estimated obstructive sleep apnea prevalence was 46% (59% men, 33% women) for an apnea-hypopnea index ≥5%, and 21% (30% men, 13% women) for an apnea-hypopnea index ≥ 15. The estimated obstructive sleep apnea syndrome prevalence (apnea-hypopnea index ≥5; Epworth Sleepiness Scale >10) was 6%. The prevalence of obstructive sleep apnea continuously increased with age for men and women with, however, later onset for women. Gender, age, body mass index, waist-to-hip ratio, snoring, alcohol consumption (for women only) and self-reported cardiovascular diseases were significantly positively associated with obstructive sleep apnea, whereas daytime sleepiness was not. Diabetes, hypertension and metabolic syndrome were positively associated with severe obstructive sleep apnea. The associations became non-significant after adjustment for body mass. Women exhibited stronger associations than men. The prevalence of obstructive sleep apnea was high, with almost half the population presenting some kind of obstructive sleep apnea. The continuous increase of obstructive sleep apnea with age challenges the current theory that mortality due to obstructive sleep apnea and cardiovascular co-morbidities affect obstructive sleep apnea prevalence at an advanced age. Also, gender differences regarding obstructive sleep apnea and associations are significant for recognizing obstructive sleep apnea mechanisms and therapy responsiveness.

CPAP effects on atherosclerotic plaques in patients with sleep-disordered breathing and coronary artery disease: The ENTERPRISE trial

BACKGROUND

Sleep-disordered breathing (SDB) is a novel cardiovascular risk factor. To date, the effects of continuous positive airway pressure (CPAP) on coronary plaque atheroma in SDB patients with coronary artery disease (CAD) have remained unclear. The CPAP Effects on Atherosclerotic Plaques in Patients with Sleep-Disordered Breathing and Coronary Artery Disease (ENTERPRISE) trial was designed to evaluate the effects of CPAP treatment in addition to optimal medical treatment on coronary plaque regression in SDB patients.

METHODS

This study is planned as a prospective, randomized, open-label, single-center study. The presence of SDB is defined as a 3% oxygen desaturation index (ODI) of ≥15 events/h as measured by nocturnal pulse oximetry. A total of 100 eligible SDB patients undergoing intravascular ultrasound (IVUS)-guided percutaneous coronary intervention will be randomly assigned to either CPAP as add-on therapy or no CPAP for SDB (1:1 ratio for CPAP vs. no CPAP). The intervention will consist of 12 months of CPAP treatment. The primary endpoint will be percentage changes in plaque atheroma volume of the non-culprit lesion segment as measured by IVUS. A specialist sleep cardiology team will carefully monitor patients receiving CPAP treatment in order to quickly detect and resolve problems, and to motivate patients to continue treatment.

CONCLUSION

This study will provide novel information on the effects of SDB and its treatment with CPAP on coronary plaque stability with regard to secondary prevention of CAD.

Influence of sleep-disordered breathing assessed by pulse oximetry on long-term clinical outcomes in patients who underwent percutaneous coronary intervention

BACKGROUND

Sleep-disordered breathing (SDB) has been recognized as an important risk factor for coronary artery disease (CAD). However, SDB was not fully examined, because sleep studies are limited. Nocturnal pulse oximetry has been suggested to be a useful tool for evaluating SDB. Therefore, the aim of this study was to investigate the influence of SDB assessed by nocturnal pulse oximetry on clinical outcomes in patients who underwent percutaneous coronary intervention (PCI).

METHODS

We conducted a prospective, multicenter, observational cohort study, wherein SDB was assessed by finger pulse oximetry in patients who underwent PCI from January 2014 to December 2016. SDB was defined as 4% oxygen desaturation index of 5 and higher. The primary endpoint was major adverse cardiac or cerebrovascular event (MACCE), defined as a composite of all-cause mortality, acute coronary syndrome, and/or stroke.

RESULTS

Of 539 patients, 296 (54.9%) had SDB. MACCE occurred in 32 patients (5.8%) during a median follow-up of 1.9 years. The cumulative incidence of MACCE was significantly higher in patients with SDB (P = 0.0134). In the stepwise multivariable Cox proportional model, the presence of SDB was a significant predictor of MACCE (hazard ratio 2.26; 95% confidence interval 1.05-5.4, P = 0.036).

CONCLUSIONS

SDB determined by nocturnal pulse oximetry was associated with worse clinical outcomes in patients who underwent PCI. Screening for SDB with nocturnal pulse oximetry was considered to be important for risk stratification in patients with CAD.

Association of obstructive sleep apnea with cardiovascular outcomes after percutaneous coronary intervention: A systematic review and meta-analysis

The relationship between obstructive sleep apnea (OSA) and adverse cardiovascular outcomes in patients undergoing percutaneous coronary intervention (PCI) remains unclear. We performed a systematic review and meta-analysis to assess the impact of OSA on subsequent cardiovascular events after PCI.We searched the PubMed, EMBASE, and Cochrane library from their inceptions to August 5, 2017. We included cohort studies that described the association between OSA (based on apnea-hypopnea index) and cardiovascular outcomes after PCI with stenting. The primary endpoint was major adverse cardiovascular event (MACE), including all-cause or cardiovascular death, myocardial infarction, stroke, repeat revascularization, or heart failure. Outcomes data were pooled using random effects models and heterogeneity was assessed with the I statistic.We identified 9 studies with 2755 participants. The prevalence of OSA in patients treated with PCI ranged from 35.3% to 61.8%. OSA was associated with increased risk of MACE after PCI (pooled risk ratio [RR] 1.96, 95% confidence interval [CI]: 1.36-2.81, P < .001, I = 54%). Between-study heterogeneity was partially explained by sample size (2 studies with ≤100 participants; RR 9.12, 95% CI: 2.69-31.00, I = 0% vs 7 studies with >100 participants; RR 1.64, 95% CI: 1.23-2.18, I = 35%). Moreover, the presence of OSA significantly increased the incidence of all-cause death (4 studies), cardiovascular death (4 studies), and repeat revascularization (7 studies) in patients undergoing PCI.Patients with OSA are at greater risk of subsequent cardiovascular events after PCI. Whether treatment of OSA prevents such events warrants further investigation.

Prevalence of Sleep-Disordered Breathing and Patient Characteristics in a Coronary Artery Disease Cohort Undergoing Cardiovascular Rehabilitation

PURPOSE

Coronary artery disease (CAD) is a leading cause of death and identification of risk factors for CAD is crucial. One such potential risk factor is sleep-disordered breathing (SDB). This prospective cohort study investigated the prevalence of SDB and determined risk factors for the presence of SDB in a large CAD cohort undergoing cardiac rehabilitation.

METHODS

A total of 1425 patients with confirmed CAD starting rehabilitation were screened for SDB using cardiorespiratory polygraphy (n = 921) or polygraphy plus pulse oximetry (n = 484).

RESULTS

A total of 1408 patients were included; 69.5% were male, 78% had acute coronary syndrome, and 22% had stable CAD. The prevalence of SDB (apnea-hypopnea index [AHI] ≥5/h) was 83%. Moderate to severe SDB (AHI ≥15/h) was present in 53%. Up to 70% of coronary artery bypass graft (CABG) recipients had an AHI ≥15/h versus 33% of those who had not undergone CABG. SDB severity did not vary significantly in patients with stable CAD or on the basis of left ventricular ejection fraction. SDB was more severe and the frequency of oxygen desaturation was higher in men than in women. Multivariate logistic regression identified age, sex, body mass index, and CABG as independent risk factors for severe SDB.

CONCLUSION

SDB is a highly prevalent comorbidity in patients with CAD, particularly those who have undergone CABG. These results strengthen existing associations and emphasize the importance of diagnosing and monitoring SDB in patients with CAD entering a cardiac rehabilitation program. Early diagnosis and intervention has the potential to have a beneficial effect on CAD prognosis.

Endothelin-1 and ET receptors impair left ventricular function by mediated coronary arteries dysfunction in chronic intermittent hypoxia rats

Obstructive sleep apnea (OSA) results in cardiac dysfunction and vascular endothelium injury. Chronic intermittent hypoxia (CIH), the main characteristic of OSAS, is considered to be mainly responsible for cardiovascular system impairment. This study is aimed to evaluate the role of endothelin‐1(ET‐1) system in coronary injury and cardiac dysfunction in CIH rats. In our study, Sprague–Dawley rats were exposed to CIH (FiO₂ 9% for 1.5 min, repeated every 3 min for 8 h/d, 7 days/week for 3 weeks). After 3 weeks, the left ventricular developed pressure (LVDP) and coronary resistance (CR) were measured with the langendorff mode in isolated hearts. Meanwhile, expressions of ET‐1 and ET receptors were detected by immunohistochemical and western blot, histological changes were also observed to determine effects of CIH on coronary endothelial cells. Results suggested that decreased LVDP level combined with augmented coronary resistance was exist in CIH rats. CIH could induce endothelial injury and endothelium‐dependent vasodilatation dysfunction in the coronary arteries. Furthermore, ET‐1 and ET_A receptor expressions in coronary vessels were increased after CIH exposure, whereas ET_B receptors expression was decreased. Coronary contractile response to ET‐1 in both normoxia and CIH rats was inhibited by ET_A receptor antagonist BQ123. However, ET_B receptor antagonist BQ788 enhanced ET‐1‐induced contractile in normoxia group, but had no significant effects on CIH group. These results indicate that CIH‐induced cardiac dysfunction may be associated with coronary injury. ET‐1 plays an important role in coronary pathogenesis of CIH through ET_A receptor by mediating a potent vasoconstrictor response. Moreover, decreased ET_B receptor expression that leads to endothelium‐dependent vasodilatation decline, might be also participated in coronary and cardiac dysfunction.

Validation of a non-contact screening device for the combination of sleep-disordered breathing and periodic limb movements in sleep

PURPOSE

Recent studies found that the non-contact screening device SleepMinder (ResMed Sensor Technologies, Dublin, Ireland) detects sleep-disordered breathing (SDB) with high diagnostic accuracy in cohorts suspected of this disorder. However, it was reported that in patients with periodic limb movement in sleep (PLMS), this non-contact device overestimates the apnea-hypopnea index (AHI). We aimed to overcome this limitation by introducing the novel sleep disorder index (SDI) which is sum of the AHI and the period limb movement index (PLMI).

METHODS

Between January 2011 and December 2013, we studied a mixed cohort of 57 patients (31 OSA, 19 PLMS). The easy-to-use non-contact device emits a very weak electromagnetic radiation and detects body movement by measuring the Doppler effect. We interpreted the device-generated movement index as the SDI and validated the diagnostic accuracy against simultaneous application of the gold-standard polysomnography (PSG).

RESULTS

We found that the SDI of the non-contact device correlated well with the sum of AHI and PLMI derived from PSG (r = 0.79, p = 0.01). For PSG-derived SDI cutoff ≥ 15/h, we obtained a sensitivity of 92.2% and a specificity of 95.8%. Positive likelihood ratio was 23.3 and negative likelihood ratio 0.03.

CONCLUSIONS

The studied non-contact screening device detects accurately the combination of the sleep disorders SDB and/or PLM. However, further testing is required in order to specify the nature of the underlying sleep disorder. At the current stage of algorithm development, the clinical strength is that the studied non-contact device can be used as a rule-out screening device for SDB and PLM.

Association of Obstructive Sleep Apnea With Subclinical Cardiovascular Disease Predicted by Coronary Artery Calcium Score in Asymptomatic Subjects

The aim of this study is to determine the association among various sleep parameters for obstructive sleep apnea (OSA) and subclinical cardiovascular disease measured by coronary artery calcium (CAC) score. A cross-sectional study was conducted among 461 patients who underwent both polysomnography (PSG) and coronary artery computed tomography to evaluate CAC score. For each participant, coronary artery computed tomography was conducted within 12 months of PSG. We evaluated the possible association among various PSG parameters by evaluating overnight-attended PSG and CAC. A univariate analysis with lowest SaO₂ and stage 3 sleep % during sleep was significantly associated with CAC score (β = -5.528, 95% confidence interval [CI] -9.179 to -1.777, p = 0.004 and β = -8.658, 95% CI -16.461 to -0.855, p = 0.030, respectively). However, after adjustment for possible confounders, only the lowest SaO₂ was independently associated with CAC score (β = -5.234, 95% CI -9.215 to -1.253, p = 0.010). This association was stronger in participants aged ≥60 years (β = -26.966, 95% CI -41.874 to -12.058, p = 0.001). In a univariate analysis, apnea-hypopnea index, stage 3 sleep %, and moderate and severe OSA were significantly associated with CAC presence (odds ratio [OR] 1.010, p = 0.035; OR 0.949, p = 0.039; OR 2.186, p = 0.013; and OR 2.019, p = 0.020, respectively). However, after adjusting for possible confounders, there was no significant association. In conclusion, the patients with intermittent hypoxemia during sleep should be considered for evaluation of coronary artery calcification to detect cardiovascular disease in subclinical status.

Impact of High Risk for Obstructive Sleep Apnea on Survival after Acute Coronary Syndrome: Insights from the ERICO Registry

Background

Obstructive sleep apnea (OSA) is a very often clinical condition that can be associated with high mortality risk, particularly in coronary heart disease (CHD). The diagnosis of OSA is not always accessible via the gold-standard method polysomnography.

Objective

To evaluate long-term influence of the high risk for OSA on fatal and non-fatal outcomes after acute coronary syndrome (ACS) in the Acute Coronary Syndrome Registry Strategy (ERICO) Study using the Berlin questionnaire as a surrogate.

Methods

Berlin questionnaire, a screening questionnaire for OSA, was applied in 639 cases of ACS 30 days after the index event. Cox regression proportional-hazards model was used to calculate the hazard ratio (HR) of all-cause, cardiovascular and CHD (myocardial infarction) mortality, as well as, the combined endpoint of fatal or recurrent non-fatal CHD.

Results

The high-risk group for OSA had higher frequencies of previous personal/family history of CHD and diabetes, in addition to a poorer event-free survival, as compared to the low-risk group (p-log-rank=0.03). The HR for fatal or recurrent non-fatal CHD was 4.26 (95% confidence interval, 1.18 - 15.36) in patients at high risk for OSA compared to those at low risk for OSA after a 2.6-year mean follow-up.

Conclusions

Using Berlin questionnaire, we were able to identify high risk for OSA as an independent predictor of non-fatal reinfarction or CHD mortality in post-ACS individuals in a long-term follow-up.

Gelatinases and their tissue inhibitors in a group of subjects with obstructive sleep apnea syndrome

Obstructive sleep apnea syndrome (OSAS) is associated with an elevated risk of cardiovascular events and stroke. Matrix metalloproteinases (MMPs) are endopeptidases involved in extracellular matrix degradation and then in the development and progression of cardiovascular diseases. Our aim was to evaluate plasma levels of gelatinases (MMP-2 and MMP-9) and their tissue inhibitors (TIMP-1 and TIMP-2) in a group of subjects with OSAS. We enrolled 48 subjects (36 men and 12 women; mean age 49.7 ± 14.68 yrs) with OSAS diagnosed with a 1-night cardiorespiratory study and then we subdivided these subjects into two subgroups according to the apnea/hypopnea index (AHI): Low (L = 21 subjects with AHI <30) and High (H = 27 subjects with AHI >30). We measured plasma concentration of the gelatinases and their inhibitors using ELISA kits. We observed a significant increase in plasma concentration of MMP-9, MMP-2, TIMP-1 and TIMP-2 in the entire group of OSAS subjects and in the two subgroups, with higher levels in the H in comparison with the L subgroup. In the whole group of OSAS subjects we also noted a significant decrease in MMP-9/TIMP-1 ratio in comparison with normal controls. Only MMP-9 was significantly correlated with the severity of the disease, expressed as AHI, with the oxygen desaturation index and also with the mean oxygen saturation. MMPs pattern is altered in OSAS and significantly influenced by the severity of the disease; it probably contributes to the vascular remodeling that leads to the atherosclerotic disease and cardiovascular complications.

Sleep Assessment in Large Cohort Studies with High-Resolution Accelerometers

Accelerometry can be a practical replacement for polysomnography in large observational studies. This review discusses the need for sleep characterization in large observational studies, exemplified by the practices of the ongoing German National Cohort study. After brief descriptions of the physical principles and state-of-the-art accelerometer devices and an overview of public data analysis algorithms for sleep-wake differentiation, we demonstrate that the spectral properties of acceleration data provide additional features that can be exploited. This leads to a periodogram-based sleep detection algorithm. Finally, we address issues of data handling and quality assurance in large cohort studies.

Obstructive sleep apnea is independently associated with subclinical coronary atherosclerosis among middle-aged women

PURPOSE

Obstructive sleep apnea (OSA) is associated with coronary disease among men. However, this association is not clear for women. In this study, we evaluate the association between OSA and presence of subclinical atherosclerosis assessed by tomographic coronary calcium score in middle-aged women.

METHODS

We evaluated consecutive women aged between 45 and 65 years in perimenopause or postmenopause period (with menstrual irregularity-amenorrhea > 60 days), without manifest cardiovascular disease (heart failure, coronary disease, and stroke), from two gynecologic clinics. All patients underwent clinical evaluation, computed tomographic examination for coronary artery calcium (CAC > 100 Agatston units), and portable sleep study. Multiple logistic regression models were used to evaluate the association between OSA and CAC, controlling for traditional risk factors including Framingham Risk Score (FRS), body mass index (BMI), and diabetes.

RESULTS

We studied 214 women (age 56 years (52-61); BMI 28 kg/m² (25-31), 25 % diabetes, 62 % hypertension). OSA (apnea-hypopnea index (AHI) ≥5 events/h) was diagnosed in 82 women (38.3 %). CAC was more prevalent in patients with moderate/severe OSA (AHI ≥15 events/h) than in patients without or with mild OSA, 19 % vs 4.5 and 1.6 %, respectively (p < 0.01). Moderate to severe OSA was associated with CAC in unadjusted (odds ratio = 6.25, 95 % CI 1.66-23.52; p < 0.01) and adjusted (odds ratio = 8.19, 95 % CI 1.66-40.32; p = 0.01) logistic regression analysis.

CONCLUSION

Moderate to severe OSA is independently associated with the presence of CAC in middle-aged women. These results reinforce the concept that women are also susceptible to the cardiovascular consequences of OSA.

Systemic inflammation in patients with compromised upper airway anatomy and primary snoring or mild obstructive sleep apnea

Our aim was to study associations between serum fibrinogen and C-reactive protein (CRP) levels and respiratory parameters on polysomnography (PSG) in patients with snoring as their main complaint and compromised upper airway anatomy. In this retrospective study, consecutive patients (43 female and 132 male; age range 11-82 years, respiratory distress index-RDI range 0.1-94.4/h) with snoring as their main complaint and compromised upper airway anatomy who underwent PSG were assessed. Spearman's Rho coefficients between RDI, AI (apnea index), hypopnea index (HI), average and lowest SpO2 (in %) and CRP- and fibrinogen serum levels were calculated. Comparisons between groups were made using Wilcoxon-W test. Patients with CRP > 5 mg/dl (22 % of the cohort) had significantly increased RDI, AI, average and lowest SpO2 than patients with CRP < 5 mg/dl. Increased correlation coefficients were observed for average SpO2 (-0.386), RDI (0.355), lowest SpO2 (-0.323) and AI (0.309). Patients with fibrinogen >350 mg/dl (in 33 %) had significantly increased RDI, HI, AI, average and lowest SpO2 than patients with fibrinogen <350 mg/dl. Increased correlation coefficients were found for average (-0.340) and lowest (-0.268) SpO2, RDI (0.236) and AI (0.229). Even patients with RDI < 15/h had increased serum CRP-(in 11 %) and/or fibrinogen-(in 19 %) levels. Simultaneous elevation of both CRP and fibrinogen levels occurred only in patients with RDI > 5/h. Systemic inflammation is strongly associated with average and lowest SpO2, RDI and AI (and with HI) in snorers with compromised upper airway anatomy and is present even in patients with primary snoring and mild obstructive sleep apnea.

Obstructive Sleep Apnea and Cardiovascular Events After Percutaneous Coronary Intervention

BACKGROUND

There is a paucity of data from large cohort studies examining the prognostic significance of obstructive sleep apnea (OSA) in patients with coronary artery disease. We hypothesized that OSA predicts subsequent major adverse cardiac and cerebrovascular events (MACCEs) in patients undergoing percutaneous coronary intervention.

METHODS AND RESULTS

The Sleep and Stent Study was a prospective, multicenter registry of patients successfully treated with percutaneous coronary intervention in 5 countries. Between December 2011 and April 2014, 1748 eligible patients were prospectively enrolled. The 1311 patients who completed a sleep study within 7 days of percutaneous coronary intervention formed the cohort for this analysis. Drug-eluting stents were used in 80.1% and bioresorbable vascular scaffolds in 6.3% of the patients, and OSA, defined as an apnea-hypopnea index of ≥15 events per hour, was found in 45.3%. MACCEs, a composite of cardiovascular mortality, nonfatal myocardial infarction, nonfatal stroke, and unplanned revascularization, occurred in 141 patients during the median follow-up of 1.9 years (interquartile range, 0.8 years). The crude incidence of an MACCEs was higher in the OSA than the non-OSA group (3-year estimate, 18.9% versus 14.0%; p=0.001). Multivariate Cox regression analysis indicated that OSA was a predictor of MACCEs, with an adjusted hazard ratio of 1.57 (95% confidence interval, 1.10-2.24; P=0.013), independently of age, sex, ethnicity, body mass index, diabetes mellitus, and hypertension.

CONCLUSIONS

OSA is independently associated with subsequent MACCEs in patients undergoing percutaneous coronary intervention. Evaluation of therapeutic approaches to mitigate OSA-associated risk is warranted.

CLINICAL TRIAL REGISTRATION

URL: http://www.clinicaltrials.gov. Unique identifier: NCT01306526.

Hidden Markov modelling of intra-snore episode behavior of acoustic characteristics of obstructive sleep apnea patients

Obstructive sleep apnea (OSA) is a breathing disorder that can cause serious medical consequences. It is caused by full (apnea) or partial (hypopnea) obstructions of the upper airway during sleep. The gold standard for diagnosis of OSA is the polysomnography (PSG). The main measure for OSA diagnosis is the apnea-hypopnea index (AHI). However, the AHI is a time averaged summary measure of vast amounts of information gathered in an overnight PSG study. It cannot capture the dynamic characteristics associated with apnea/hypopnea events and their overnight distribution. The dynamic characteristics of apnea/hypopnea events are affected by the structural and functional characteristics of the upper airway. The upper airway characteristics also affect the upper airway collapsibility. These effects are manifested in snoring sounds generated from the vibrations of upper airway structures which are then modified by the upper airway geometric and physical characteristics. Hence, it is highly likely that the acoustical behavior of snoring is affected by the upper airway structural and functional characteristics. In the current work, we propose a novel method to model the intra-snore episode behavior of the acoustic characteristics of snoring sounds which can indirectly describe the instantaneous and temporal dynamics of the upper airway. We model the intra-snore episode acoustical behavior by using hidden Markov models (HMMs) with Mel frequency cepstral coefficients. Assuming significant differences in the anatomical and physiological upper airway configurations between low-AHI and high-AHI subjects, we defined different snorer groups with respect to AHI thresholds 15 and 30 and also developed HMM-based classifiers to classify snore episodes into those groups. We also define a measure called instantaneous apneaness score (IAS) in terms of the log-likelihoods produced by respective HMMs. IAS indicates the degree of class membership of each episode to one of the predefined groups as well as the instantaneous OSA severity. We then assigned each patient to an overall AHI band based on the majority vote of each episode of snoring. The proposed method has a diagnostic sensitivity and specificity between 87-91%.

Association of short-term ozone and temperature with sleep disordered breathing

Scarce evidence suggests that ambient air pollution and temperature might play a role in incidence and severity of sleep disordered breathing (SDB). We investigated the association of short-term exposure to fine particulate matter (particles with a 50% cut-off aerodynamic diameter of 10 μm (PM10)), ozone and temperature with SDB in the general population. Between 2006 and 2008, 1773 participants (aged 50-80 years) of the Heinz Nixdorf Recall study underwent screening for SDB, as defined by the apnoea-hypopnoea index (AHI). We assessed daily exposure to PM10, ozone, temperature and humidity. We used multiple linear regression to estimate associations of daily PM10, ozone levels and temperature on the day of screening, adjusting for relative humidity, season, age, sex, body mass index, education, smoking habits, alcohol consumption and physical activity. In the study population, the mean±sd AHI was 11.2±11.4 events·h(-1). Over all seasons, an interquartile range increase in temperature (8.6°C) and ozone (39.5 µg·m(-3)) was associated with a 10.2% (95% CI 1.2-20.0%) and 10.1% (95% CI 2.0-18.9%) increase in AHI, respectively. Associations for temperature were stronger in summer, yielding a 32.4% (95% CI 0.0-75.3%) increase in AHI per 8.6°C (p-value for season-temperature interaction 0.08). We observed that AHI was not associated with PM10. This study suggests that short-term variations in ozone concentration and temperature are associated with SDB.

Objectively measured sleep characteristics and prevalence of coronary artery calcification: the Multi-Ethnic Study of Atherosclerosis Sleep study

BACKGROUND

We tested whether objectively measured indices of obstructive sleep apnoea (OSA) and sleep quality are associated with coronary artery calcification (CAC) prevalence independent of obesity, a classic confounder.

METHODS

1465 Multi-Ethnic Study of Atherosclerosis participants (mean age 68 years), who were free of clinical cardiovascular disease, had both coronary CT and in-home polysomnography and actigraphy performed. OSA categories were defined by the Apnea-Hypopnea Index (AHI). Prevalence ratios (PRs) for CAC >0 and >400 (high burden) were calculated.

RESULTS

Participants with severe OSA (AHI ≥30; 14.6%) were more likely to have prevalent CAC, relative to those with no evidence of OSA, after adjustment for demographics and smoking status (PR 1.16; 95% CI 1.06 to 1.26), body mass index (1.11; 1.02 to 1.21) and traditional cardiovascular risk factors (1.10; 1.01 to 1.19). Other markers of hypoxaemia tended to be associated with a higher prevalence of CAC >0. For CAC >400, a higher prevalence was observed with both a higher arousal index and less slow-wave sleep. Overall, associations were somewhat stronger among younger participants, but did not vary by sex or race/ethnicity.

CONCLUSIONS

In this population-based multi-ethnic sample, severe OSA was associated with subclinical coronary artery disease (CAC >0), independent of obesity and traditional cardiovascular risk factors. Furthermore, the associations of the arousal index and slow-wave sleep with high CAC burden suggest that higher nightly sympathetic nervous system activation is also a risk factor. These findings highlight the potential importance of measuring disturbances in OSA as well as sleep fragmentation as possible risk factors for coronary artery disease.

Minimal nocturnal oxygen saturation predicts future subclinical carotid atherosclerosis: the Wisconsin sleep cohort

Previous data on the associations between nocturnal oxygen saturation parameters and carotid atherosclerosis are conflicting. We examined the prospective associations of nocturnal oxygen saturation (SaO2 ) and cardiovascular disease (CVD) risk factors with carotid intima-media thickness (IMT) and plaques. We used data on 689 Wisconsin sleep cohort participants who had baseline overnight polysomnography followed by carotid ultrasonography a mean (SD) of 7.8 (2.5) years later. Far wall common carotid IMT was measured using B-mode ultrasound. Bilateral common, bifurcation and internal carotid artery segments were evaluated for plaque score. Participants (8) were aged 56 years (55% male); 32% had hypertension and mean body mass index (BMI) was 31 (7) kg m(2). Mean and minimum nocturnal SaO2 were 95% (2) and 86% (7), respectively. Mean percentage sleep time with SaO2 < 90% was 2% (8). Both mean (odds ratio [OR]: 0.60 lower plaque count per 5% higher mean SaO2, 95% confidence interval [CI]: 0.38-0.96, P = 0.033) and minimum SaO2 (OR: 0.88 lower plaque count per 5% higher minimum SaO2, 95% CI: 0.80-0.97, P = 0.013) predicted carotid plaque score after adjusting for age, sex and BMI. Minimum SaO2 predicted future plaque score after adding adjustment for traditional CVD risk factors (OR: 0.90 lower plaque count per 5% higher minimum SaO2, 95% CI: 0.81-0.99, P = 0.038). Mean SaO2 was not associated with carotid IMT after CVD risk factor adjustment. We conclude that minimum nocturnal SaO2 is an independent predictor of future carotid plaque burden. Other nocturnal SaO2 parameters are not associated with future carotid IMT or plaques after adjusting for traditional CVD risk factors.

The correlation of serum growth differentiation factor-15 level in patients with obstructive sleep apnea

PURPOSE

Growth differentiation factor-(GDF-) is a prognostic biomarker in cardiovascular disorders (CVD). GDF-15 level was not studied in patients with obstructive sleep apnea syndrome (OSAS) before. In this study, we investigated serum GDF-15 levels in OSAS patients and compared them with healthy controls.

MATERIAL AND METHODS

Polysomnographically, confirmed forty consecutive OSAS patients (20 men and 20 women) and forty consecutive healthy controls (23 men and 17 women) were enrolled in the study. The samples in each group had similar demographic characteristics and body mass index (BMI) values.

RESULTS

In the study, no significant correlation was found about GDF-15 levels of OSAS group and healthy controls. However, there was a significant statistical correlation between age and GDF-15 level. In correlation analysis, there was not any significant correlation between age and BMI.

CONCLUSION

Although various developing biomarkers have been studied in cardiovascular disorders, GDF-15 levels have attracted a widespread interest as predictors of cardiovascular risk. GDF-15 level has not been evaluated previously in patients with OSAS. A significant statistical correlation was found between age and GDF-15 level. To reveal close relation between OSAS and GDF-15, further studies are needed with combination of GDF-15 and other biomarkers in OSAS.

Synchronized imaging and acoustic analysis of the upper airway in patients with sleep-disordered breathing

Progressive narrowing of the upper airway increases airflow resistance and can produce snoring sounds and apnea/hypopnea events associated with sleep-disordered breathing due to airway collapse. Recent studies have shown that acoustic properties during snoring can be altered with anatomic changes at the site of obstruction. To evaluate the instantaneous association between acoustic features of snoring and the anatomic sites of obstruction, a novel method was developed and applied in nine patients to extract the snoring sounds during sleep while performing dynamic magnetic resonance imaging (MRI). The degree of airway narrowing during the snoring events was then quantified by the collapse index (ratio of airway diameter preceding and during the events) and correlated with the synchronized acoustic features. A total of 201 snoring events (102 pure retropalatal and 99 combined retropalatal and retroglossal events) were recorded, and the collapse index as well as the soft tissue vibration time were significantly different between pure retropalatal (collapse index, 2 ± 11%; vibration time, 0.2 ± 0.3 s) and combined (retropalatal and retroglossal) snores (collapse index, 13 ± 7% [P ≤ 0.0001]; vibration time, 1.2 ± 0.7 s [P ≤ 0.0001]). The synchronized dynamic MRI and acoustic recordings successfully characterized the sites of obstruction and established the dynamic relationship between the anatomic site of obstruction and snoring acoustics.

Obstructive sleep apnea and progression of coronary artery calcium: the multi-ethnic study of atherosclerosis study

Background

Obstructive sleep apnea (OSA) is a common condition associated with cardiovascular disease. Its potential effect on progression of subclinical atherosclerosis is not well understood. We tested the hypothesis that self‐reported OSA is associated with progression of coronary artery calcium (CAC). We also evaluated whether traditional cardiovascular risk factors accounted for the association.

Methods and Results

In the Multi‐Ethnic Study of Atherosclerosis (MESA) prospective cohort, we studied 2603 participants who at baseline (2002–2004) completed a sleep questionnaire and underwent coronary computed tomography (CT) and, then 8 years later (2010–2011), a repeat coronary CT. Participants were categorized by symptoms of habitual snoring or reported physician diagnosis of OSA. At baseline, 102 (3.9%) reported diagnosed OSA; 666 (25.6%) reported diagnosed habitual snoring; and 1835 (70.5%) reported neither habitual snoring nor OSA (“normal”). At baseline, CAC prevalence was highest among those with OSA but similar for those with and without habitual snoring. During 8 years of follow‐up, greater progression of CAC was observed among those with OSA versus normal (mean increase of 204.2 versus 135.5 Agatston units; P=0.01), after accounting for demographics, behaviors, and body habitus. Modest attenuation was observed after adjustment for cardiovascular risk factors (188.7 versus 138.8; P=0.06). CAC progression among habitual snorers was similar to that observed in the normal group.

Conclusions

OSA was associated with CAC score progression after adjustment for demographics, behaviors, and body mass index. However, the association was not significant after accounting for cardiovascular risk factors, which may mediate the association between OSA and CAC.

Systematic review on noninvasive assessment of subclinical cardiovascular disease in obstructive sleep apnea: new kid on the block!

Patients with obstructive sleep apnea (OSA) have a high burden of cardiovascular disease (CVD) but a causal relationship between OSA and atherosclerotic CVD remains unclear. We systematically reviewed the literature analyzing the relationship. A review of the Medline database for studies noninvasively evaluating subclinical CVD in OSA was conducted. A total of fifty-two studies were included in this review. Across the studies the prevalence of atherosclerosis, as assessed by coronary artery calcification, carotid intima-media thickness, brachial artery flow-mediated dilation and pulse wave velocity was higher in patients with OSA and correlated with increasing severity and duration of OSA. This study shows OSA is an independent predictor of subclinical CVD as CVD is more likely to occur in patients with long standing and severe OSA. Further research is however necessary to identify specific OSA populations that would benefit from aggressive screening.