Obstructive sleep apnea severity is associated with left ventricular mass independent of other cardiovascular risk factors in morbid obesity

Nocturnal hypoxia indexes are associated with left ventricular remodeling and diastolic dysfunction in obstructive sleep apnea patients

BACKGROUND AND OBJECTIVE

Obstructive sleep apnea (OSA) is associated with heart derangements detected at echocardiography as higher left ventricular mass index (LVMI), higher left ventricular end-diastolic diameter, lower left ventricular ejection fraction (LVEF), and impaired diastolic function. However, the currently used parameter to define OSA diagnosis and severity, the apnea/hypopnea index (AHI), poorly predicts cardiovascular damage, cardiovascular events, and mortality. Our study aimed to assess if other polygraphic indices of OSA presence and severity, in addition to AHI, might better predict echocardiographic cardiac remodeling.

METHODS AND RESULTS

We enrolled two cohorts of individuals referred for suspected OSA to the outpatient facilities of the IRCCS Istituto Auxologico Italiano, Milano, and of the Clinica Medica 3, Padova. All patients underwent home sleep apnea testing and echocardiography. Based on the AHI the cohort was divided into no-OSA (AHI<15 events/hour) and moderate-severe OSA (AHI≥15 events/hour). We recruited 162 patients and found that compared to patients with no-OSA, those with moderate-severe OSA showed higher LV remodeling [left ventricular end-diastolic volume (LVEDV) 48.4 ± 11.5 ml/m2 vs. 54.1 ± 14.0 ml/m2, respectively, p = 0.005] and lower LVEF (65.3 ± 5.8% vs. 61.6 ± 7.8%, respectively, p = 0.002), whereas we could not find any difference in LVMI and early and late ventricular filling velocity ratio (E/A). At multivariate linear regression analysis two polygraphic hypoxic burden-related markers were independent predictors of LVEDV and E/A, i.e., the percentage of time with O2 saturation below 90% (β = 0.222) and ODI (β = -0.422), respectively.

CONCLUSIONS

Our study shows that nocturnal hypoxia-related indexes were associated with left ventricular remodeling and diastolic dysfunction in OSA patients.

Aggravating effect of obstructive sleep apnoea on left ventricular remodelling and function disorder in patients with type 2 diabetes mellitus: a case-control study by 3D speckle tracking echocardiography

OBJECTIVES

The purpose of this study was to evaluate the early alterations of left ventricular (LV) structure and function in type 2 diabetes mellitus (T2DM) patients with or without obstructive sleep apnoea (OSA) using 3 D speckle tracking echocardiography (3DSTE).

METHODS

Eighty T2DM patients with preserved LVEF were included, half of whom had OSA as co-morbidity. Forty age- and sex-matched controls were also enrolled. LV structure and function were evaluated by conventional echocardiography and 3DSTE. LV global longitudinal strain (GLS), global circumferential strain (GCS), global area strain (GAS), and global radial strain (GRS) were all measured by 3DSTE.

RESULTS

Four geometric patterns (normal geometry, concentric remodelling, concentric and eccentric hypertrophy) occupied significantly different proportions within the three groups (p = .014). LV remodelling made up higher shares in two T2DM groups than in the controls, whereas LV hypertrophy appeared most frequently in the patients with T2DM and OSA. The patients with T2DM alone had significantly lower GLS and GCS than the controls (both p < .01). The patients with T2DM and OSA had significantly lower GLS, GCS, GAS, and GRS than the controls and the patients with T2DM alone (all p < .01). Fasting plasma glucose (FPG), OSA and BMI had negative impacts on all and part of the strain values in T2DM patients. The T2DM patients with moderate-to-severe OSA showed significantly lower GLS, GCS, GAS, and GRS than those with mild OSA (all p < .05).

CONCLUSIONS

The 3DSTE plus conventional echocardiography could detect the sub-clinical LV alterations in T2DM patients with or without OSA.

Cardiac consequences of intermittent hypoxia: a matter of dose? A systematic review and meta-analysis in rodents

Aim

Intermittent hypoxia (IH) is considered to be a major contributor to obstructive sleep apnoea-related cardiovascular consequences. The present meta-analysis aimed to assess the effects of IH on cardiac remodelling, function and infarct size after myocardial ischaemia across different rodent species and IH severities.

Methods and results

Relevant articles from PubMed, Embase and Web of Science were screened. We performed a random effect meta-analysis to assess the effect of IH on myocardium in rodents by using standardised mean difference (SMD). Studies using rodents exposed to IH and outcomes related to cardiac remodelling, contractile function and response to myocardial ischaemia–reperfusion were included. 5217 articles were screened and 92 were included, demonstrating that IH exposure induced cardiac remodelling, characterised by cardiomyocyte hypertrophy (cross-sectional area: SMD=2.90, CI (0.82–4.98), I²=94.2%), left ventricular (LV) dilation (LV diameter: SMD=0.64, CI (0.18–1.10), I²=88.04%), interstitial fibrosis (SMD=5.37, CI (3.22–7.53), I²=94.8) and apoptosis (terminal deoxynucleotidyl transferase dUTP nick end labelling: SMD=6.70, CI (2.96–10.44), I²=95.9). These structural changes were accompanied by a decrease in LV ejection fraction (SMD=−1.82, CI (−2.52–−1.12), I²=94.22%). Importantly, most of the utilised IH protocols mimicked extremely severe hypoxic disease. Concerning infarct size, meta-regression analyses highlighted an ambivalent role of IH, depending on its severity. Indeed, IH exposure with inspiratory oxygen fraction (F_IO2) <7% was associated with an increase in infarct size, whereas a reduced infarct size was reported for F_IO2 levels above 10%. Heterogeneity between studies, small study effect and poor reporting of methods in included articles limited the robustness of the meta-analysis findings.

Conclusion

This meta-analysis demonstrated that severe IH systematically induces cardiac remodelling and contractile dysfunction in rodents, which might trigger or aggravate chronic heart failure. Interestingly, this meta-analysis showed that, depending on stimulus severity, IH exhibits both protective and aggravating effects on infarct size after experimental ischaemia–reperfusion procedures.

This meta-analysis shows that IH induces cardiac remodelling and contractile dysfunction in rodents, independently of IH characteristics. Conversely, the dual response to myocardial ischaemia–reperfusion seems to be related to IH intensity and duration.https://bit.ly/3rdnR32

Obstructive sleep apnoea syndrome and left ventricular hypertrophy: a meta-analysis of echocardiographic studies

AIM

We investigated the association between obstructive sleep apnoea (OSA) and subclinical cardiac organ damage through a meta-analysis of echocardiographic studies that provided data on left ventricular hypertrophy (LVH), assessed as a categorical or continuous variable.

DESIGN

The PubMed, OVID-MEDLINE, and Cochrane library databases were systematically analyzed to search English-language articles published from 1 January 2000 to 15 August 2019. Studies were detected by using the following terms: 'obstructive sleep apnea', 'sleep quality', 'sleep disordered breathing', 'cardiac damage', 'left ventricular mass', 'left ventricular hypertrophy', and 'echocardiography'.

RESULTS

Meta-analysis included 5550 patients with OSA and 2329 non-OSA controls from 39 studies. The prevalence of LVH in the pooled OSA population was 45% (CI 35--55%). Meta-analysis of studies comparing the prevalence of LVH in participants with OSA and controls showed that OSA was associated with an increased risk of LVH (OR = 1.70, CI 1.44-2.00, P < 0.001). LV mass was significantly increased in patients with severe OSA as compared with controls (SMD 0.46 ± 0.08, CI 0.29-0.62, P < 0.001) or with mild OSA. This was not the case for studies comparing patients with unselected or predominantly mild OSA and controls (0.33 ± 0.17, CI -0.01 to 0.67, P = 0.057).

CONCLUSION

The present meta-analysis expands previous information on the relationship between OSA and echocardiographic LVH, so far based on individual studies. The overall evidence strongly suggests that the likelihood of LVH increases with the severity of OSA, thus exhibiting a continuous relationship.

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.

Left Ventricular Geometrical Changes in Severely Obese Adolescents: Prevalence, Determinants, and Clinical Implications

Left ventricular hypertrophy (LVH) is independently associated with a higher risk of cardiovascular morbidity and mortality in adults. Adiposity is a risk factor for LVH, independent of blood pressure. Potential causes of this nonhemodynamic pathogenesis identified in adults include adverse body fat distribution, insulin resistance, dyslipidemia, and obstructive sleep apnea syndrome (OSA). In severely obese adolescents, the determinants of obesity-induced changes in left ventricular structure are poorly characterized. Cardiac ultrasonographic, demographic, anthropometric, and comorbidity-related data were prospectively collected in adolescents with severe obesity refractory to conservative treatment who presented for surgical therapy. Differences between adolescents with LVH and without LVH were evaluated using independent samples t, chi-square, or Fisher's exact test. Multivariable linear regression analysis was performed to evaluate associations with left ventricular structural changes, corrected for body mass index (BMI) z score. Forty-three patients entered analysis, of whom 24 (55.8%) showed LVH. The most common geometrical change was eccentric LVH (eLVH), occurring in 21 subjects (48.8%). Demographic and anthropometric variables did not differ between patients with and without LVH. Independent of BMI z score, left ventricular mass index was significantly associated with apnea-hypopnea index (AHI) (regression parameter B = 0.8; 95% CI 0.3 to 1.2). Interventricular septum thickness (IVST) was significantly associated with HOMA-IR values (B = 0.1; 95% CI 0.04 to 0.2), HDL-cholesterol (B = - 1.2; 95% CI - 2.2 to 0.1), and triglyceride levels (B = 0.5; 95% CI 0.001 to 0.9). LVH, especially eLVH, is highly prevalent amongst severely obese adolescents. Adverse changes in cardiac structure, increased IVST in particular, are independently associated with several nonhemodynamic comorbidities that are common in this population, namely OSA, insulin resistance, and dyslipidemia.

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

STUDY OBJECTIVES

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

METHODS

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

RESULTS

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

CONCLUSIONS

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

Association Between Sleep Disordered Breathing and Left Ventricular Function: A Cross-Sectional Analysis of the ECHO-SOL Ancillary Study

BACKGROUND

Prior studies have found that sleep-disordered breathing (SDB) is common among those with left ventricular (LV) dysfunction and heart failure. Few epidemiological studies have examined this association, especially in US Hispanic/Latinos, who may be at elevated risk of SDB and heart failure.

METHODS

We examined associations between SDB and LV diastolic and systolic function using data from 1506 adults aged 18 to 64 years in the Hispanic Community Health Study/Study of Latinos ECHO-SOL Ancillary Study (2011-2014). Home sleep testing was used to measure the apnea-hypopnea index, a measure of SDB severity. Echocardiography was performed a median of 2.1 years later to quantify LV diastolic function, systolic function, and structure. Multivariable linear regression was used to model the association between apnea-hypopnea index and echocardiographic measures while accounting for the complex survey design, demographics, body mass, and time between sleep and echocardiographic measurements.

RESULTS

Each 10-unit increase in apnea-hypopnea index was associated with 0.2 (95% CI, 0.1-0.3) lower E', 0.3 (0.1-0.5) greater E/E' ratio, and 1.07-fold (1.03-1.11) higher prevalence of diastolic dysfunction as well as 1.3 (0.3-2.4) g/m2 greater LV mass index. These associations persisted after adjustment for hypertension and diabetes mellitus. In contrast, no association was identified between SDB severity and subclinical markers of LV systolic function.

CONCLUSIONS

Greater SDB severity was associated with LV hypertrophy and subclinical markers of LV diastolic dysfunction. These findings suggest SDB in Hispanic/Latino men and women may contribute to the burden of heart failure in this population.

Targeting Concentric Left Ventricular Hypertrophy in Obstructive Sleep Apnea Syndrome. A Meta-analysis of Echocardiographic Studies

AIM

We assessed the association between obstructive sleep apnea (OSA) and left ventricular hypertrophy (LVH) subtypes (i.e., concentric and eccentric LVH) trough a meta-analysis of echocardiographic studies.

DESIGN

The PubMed, OVID-MEDLINE, and Cochrane library databases were systematically analyzed to search full papers published from 1st January 2000 to 31st August 2019. Studies were detected by using the following terms: "obstructive sleep apnea", "sleep disordered breathing", "left ventricular mass", "left ventricular geometry", "left ventricular hypertrophy", "echocardiography".

RESULTS

Meta-analysis included 1,760 patients with OSA and 1,284 non-OSA controls from 9 studies. The prevalence rates of concentric and eccentric LVH in the pooled OSA population were 24.0% (confidence interval [CI] 16.0-33.0%) and 16.0% (CI 12.0-23.0%), respectively. Meta-analysis of six studies comparing the prevalence of LVH subtypes in participants with OSA and controls showed that OSA was associated with an increased risk of both concentric (odds ratio [OR] = 1.62, CI: 1.27-2.07, P < 0.0001) and eccentric (OR = 1.34, CI: 1.07-1.67, P < 0.009) LVH, respectively.

CONCLUSIONS

Our findings suggest that in the OSA setting concentric LVH is more frequent than eccentric LVH. From a practical perspective, in consideration of the particularly adverse prognostic significance of concentric LVH, a comprehensive echocardiographic evaluation targeting LVH subtypes could improve cardiovascular risk stratification in patients with OSA.

Accelerated tumor growth under intermittent hypoxia is associated with hypoxia-inducible factor-1-dependent adaptive responses to hypoxia

Mounting evidence has revealed a causative role of intermittent hypoxia (IH) in cancer progression in mouse models of obstructive sleep apnea (OSA), but most studies have focused on the effects of IH following tumor implantation using an exposure to single IH frequency. Thus, we aimed to investigate 1) the potential effect of IH on the initial tumor growth in patients with OSA without an interaction with other mechanisms induced by IH in mice and 2) the influence of the IH frequency on tumor growth, which were tested using pre-conditioning with IH (Pre-IH) and 2 different IH frequencies, respectively. Pre-IH was achieved by alternatively maintaining melanoma cells between normoxia (10 min, 21% O₂) and hypoxia (50 min, 1% O₂) for 7 days (12 cycles per day) before administering them to mice. The conditions for IH-1 and IH-2 were 90 s of 12% FiO₂ followed by 270s of 21% FiO₂ (10 cycles/h), and 90 s of 12% FiO₂ and 90 s of 21% FiO₂ (20 cycles/h), respectively, for 8 h per day. Tumor growth was significantly higher in the Pre-IH group than in the normoxia group. In addition, the IH-2 group showed more accelerated tumor growth compared to the normoxia and IH-1 groups. Immunohistochemistry and gene-expression results consistently showed the up-regulation of molecules associated with HIF-1α-dependent hypoxic adaptation in tumors of the Pre-IH and IH-2 groups. Our findings reveal that IH increased tumor progression in a frequency-dependent manner, regardless of whether it was introduced before or after in vivo tumor cell implantation.

Waist circumference and postmenopause stages as the main associated factors for sleep apnea in women: a cross-sectional population-based study

OBJECTIVE

The current study aimed to investigate stages of reproductive aging as an associated factor for obstructive sleep apnea syndrome (OSAS) among women in a representative sample of Sao Paulo, Brazil.

METHODS

Four hundred seven women underwent clinical evaluation, polysomnography, and biochemical analysis. Stages of reproductive aging were defined as premenopause, early postmenopause, and late postmenopause.

RESULTS

OSAS was more frequent in the postmenopausal groups, with 68.4% of women affected by severe OSAS belonging to the late postmenopause group. After adjustment for potential confounding factors, associated factors for OSAS, regardless of its severity, were waist circumference, modified Mallampati score IV, and both postmenopause stages. For moderate to severe OSAS and severe OSAS, we found waist circumference and both postmenopause stages to be the main factors. We carried out a receiver operating characteristic curve analysis, which demonstrated that the cutoff value for waist circumference was 87.5 cm, with a maximum of 75.7% accuracy for the classification of women as OSAS or non-OSAS.

CONCLUSIONS

OSAS is prevalent in postmenopausal women, especially in late postmenopause. This study highlights the association between waist circumference, early postmenopause and late postmenopause, and severity of OSAS. Our findings suggest that postmenopause stages may potentially exacerbate the presence of sleep disturbance and that reducing waist circumference may be an important strategy for managing OSAS in women.

Association between Obstructive Sleep Apnea and Left Ventricular Structure by Age and Gender: the Multi-Ethnic Study of Atherosclerosis

STUDY OBJECTIVES

The presence and severity of obstructive sleep apnea (OSA) are associated with impaired left ventricular (LV) structure and function. Our goal was to quantify the associations between LV systolic function and mass with severity of OSA in an ethnically diverse cohort, assessing variations by age and sex.

METHODS

We conducted a cross-sectional analysis of data from 1,412 racially/ethnically diverse participants across 6 US communities from the Multi-Ethnic Study of Atherosclerosis who underwent both overnight polysomnography and cardiac magnetic resonance imaging from 2010-2012. We evaluated the association between the obstructive apnea-hypopnea index (AHI) by clinical category (< 5, 5-15, 15-30, 30-50, > 50) and secondary measures of sleep apnea with the outcomes left ventricular (LV) mass adjusted for height, LV mass/volume ratio, and LV ejection fraction.

RESULTS

After adjusting for potential confounders and mediators, LV mass was significantly increased with increasing AHI category for subjects age 65 y or younger (β = 1.84 ± 0.47 g/m, P = 0.0001). The association between the AHI and LV mass appeared stronger in whites and Chinese compared to blacks and Hispanics, although interaction terms were not statistically significant. Additionally, while both LV mass and LV mass/volume ratio were significantly associated with hypoxia, ejection fraction was not associated with any OSA severity index. Comparable associations were observed in men and women.

CONCLUSIONS

Independent of confounders, higher levels of AHI are significantly associated with increased LV mass in both men and women younger than 65 y from a community-based cohort.

Early major medical complications after surgical management of obstructive sleep apnea: a retrospective cohort analysis and case series

PURPOSE

The purpose of this study was to determine the frequency and relative risk (RR) of early postoperative major medical complications after surgery for the management of obstructive sleep apnea.

PATIENTS AND METHODS

This was a retrospective cohort analysis of patients who had undergone surgery for the treatment of polysomnogram-confirmed obstructive sleep apnea at 2 hospitals in Pittsburgh, PA, between 1992 and 2013. Early postoperative major medical complications were defined as either a life-threatening complication requiring intensive care unit intervention or death within the immediate hospital course. Standard demographic data, apnea-hypopnea index, Epworth Sleepiness Score, minimum nocturnal oxygen saturation, and body mass index were collected. The 2-tailed independent t test, Fisher exact test, and RR with 95% confidence interval were used.

RESULTS

A total of 267 consecutive patients who underwent surgery for obstructive sleep apnea and met the inclusion criteria were included in this study. A total of 6 patients (6 of 267, 2.2%) had early major medical postoperative complications. When stratified by surgical group (intrapharyngeal vs extrapharyngeal), there were 162 intrapharyngeal patients with 2 complications (1.2%) and 105 extrapharyngeal patients with 4 complications (3.8%). We found no statistically significant difference in frequency (2 of 162 intrapharyngeal patients [1.2%] vs 4 of 105 extrapharyngeal patients [3.8%], P = .17) or RR (3.1; 95% confidence interval, 0.58 to 16.55; P = .1885) between the groups. There were statistically significant differences for mean age, apnea-hypopnea index, Epworth Sleepiness Score, minimum nocturnal oxygen saturation, and body mass index between the surgical groups.

CONCLUSIONS

The overall frequency of early major medical postoperative complications in upper airway surgery for obstructive sleep apnea is low, with no statistically significant difference in frequency and RR between intrapharyngeal and extrapharyngeal surgery. There may, however, be a clinically significance difference in RR possibly because of associated differences in risk factors between the groups.

Factors affecting blood pressure profile in pre and postmenopausal women with obstructive sleep apnea hypopnea syndrome

PURPOSE

Obstructive sleep apnea hypopnea syndrome (OSAHS) is an independent risk factor for development of hypertension. Epidemiological surveys have found that risk of cardiovascular diseases increased in postmenopausal women. However, it is not well known about the profiles of hypertension of women with OSAHS in their different reproductive stages. This study aimed to investigate the difference of blood pressure profile between pre and postmenopausal women with OSAHS.

METHODS

Women who were tested by polysomnography (PSG) (n = 207) in Ruijin Hospital were recruited in the study. The subjects were divided into two groups of premenopausal women (24 with and 30 without OSAHS), and two groups of postmenopausal women (116 with and 37 without OSAHS). Among the groups, the differences of demographic and PSG variables were compared. The factors influencing blood pressure were further studied.

RESULTS

The prevalence of hypertension (56.9 %) in postmenopausal OSAHS patients was higher than the other three groups. Among OSAHS patients, both average systolic blood pressure (SBP) and diastolic blood pressure (DBP) of postmenopausal women were higher than those of premenopausal ones [(129.9 ± 16.16 mmHg vs. 123.7 ± 18.89), (84.96 ± 9.88 mmHg vs. 78.81 ± 10.34), P = 0.05, P < 0.01, respectively], with the elevation of DBP being more pronounced. For premenopausal women, body mass index (BMI) was the only factor affecting blood pressure (p < 0.05); in postmenopausal women, BMI was a factor affecting SBP, while BMI and apnea hypopnea index (AHI) affecting DBP (P < 0.05).

CONCLUSION

Blood pressure profile of postmenopausal women with OSAHS was affected by both BMI and AHI. But those of premenopausal ones were predominantly related to BMI.