Prevalence of left ventricular hypertrophy in persons with and without obstructive sleep apnea

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.

The association of obstructive sleep apnea and left ventricular hypertrophy in obese and overweight children with history of elevated blood pressure

Obesity is a potent cardiovascular disease (CVD) risk factor and is associated with left ventricular hypertrophy (LVH). Obstructive sleep apnea (OSA) is common among individuals with obesity and is also associated with CVD risk. The authors sought to determine the association of OSA, a modifiable CVD risk factor, with LVH among overweight/obese youth with elevated blood pressure (EBP). This was a cross-sectional analysis of the baseline visit of 61 consecutive overweight/obese children with history of EBP who were evaluated in a pediatric obesity hypertension clinic. OSA was defined via sleep study or validated questionnaire. Children with and without OSA were compared using Fisher's exact tests, Student's t tests, and Wilcoxon rank sum test. Multivariable logistic regression evaluated the association between OSA and LVH. In this cohort, 71.7% of the children had LVH. Children with OSA were more likely to have LVH (85.7% vs 59.4%, P = 0.047). OSA was associated with 4.11 times greater odds of LVH (95% CI 1.15, 14.65; P = 0.030), remaining significant after adjustment for age, sex, race, and BMI z-score (after adjustment for hypertension, P = 0.051). A severe obstructive apnea-hypopnea index (AHI >10) was associated with 14 times greater odds of LVH (95% CI 1.14, 172.64, P = 0.039). OSA was significantly associated with LVH among overweight/obese youth with EBP, even after adjustment for age, sex, race, and BMI z-score. Those with the most severe OSA (AHI >10) had the greatest risk for LVH. Future studies exploring the impact of OSA treatment on CVD risk in children are needed.

Hypertension, snoring, and obstructive sleep apnoea during pregnancy: a cohort study

OBJECTIVE

To assess the frequency of obstructive sleep apnoea among women with and without hypertensive disorders of pregnancy.

DESIGN

Cohort study.

SETTING

Obstetric clinics at an academic medical centre.

POPULATION

Pregnant women with hypertensive disorders (chronic hypertension, gestational hypertension, or pre-eclampsia) and women who were normotensive.

METHODS

Women completed a questionnaire about habitual snoring and underwent overnight ambulatory polysomnography.

MAIN OUTCOME MEASURES

The presence and severity of obstructive sleep apnoea.

RESULTS

Obstructive sleep apnoea was found among 21 of 51 women with hypertensive disorders (41%), but in only three of 16 women who were normotensive (19%, chi-square test, P=0.005). [Author correction added on 16 June 2014, after first online publication: Results mentioned in the abstract were amended.] Non-snoring women with hypertensive disorders typically had mild obstructive sleep apnoea, but >25% of snoring women with hypertensive disorders had moderate to severe obstructive sleep apnoea. Among women with hypertensive disorders, the mean apnoea/hypopnoea index was substantially higher in snorers than in non-snorers (19.9±34.1 versus 3.4±3.1, P=0.013), and the oxyhaemoglobin saturation nadir was significantly lower (86.4±6.6 versus 90.2±3.5, P=0.021). Among women with hypertensive disorders, after stratification by obesity, the pooled relative risk for obstructive sleep apnoea in snoring women with hypertension compared with non-snoring women with hypertension was 2.0 (95% CI 1.4-2.8).

CONCLUSIONS

Pregnant women with hypertension are at high risk for unrecognised obstructive sleep apnoea. Although longitudinal and intervention studies are urgently needed, given the known relationship between obstructive sleep apnoea and hypertension in the general population, it would seem pertinent that hypertensive pregnant women who snore should be tested for obstructive sleep apnoea, a condition believed to cause or promote hypertension.

Severe obstructive sleep apnea elicits concentric left ventricular geometry

BACKGROUND

Obstructive sleep apnea (OSA) has several negative effects on the heart including increase in myocardial end-systolic stress, venous return and sympathetic activity, all potential stimuli of left ventricular (LV) hypertrophy. The impact of the severity of OSA on LV geometry is unknown. We hypothesized that OSA is related to concentric LV geometry.

METHODS

One hundred and fifty-seven patients with suspected OSA underwent echocardiography, ambulatory 24-h blood pressure and ECG monitoring. On the basis of the severity of OSA, patients were divided into controls, mild OSA and moderate/severe OSA (apnea-hypopnea index <5, 5-15 and >15/h, respectively). Patients with LV hypertrophy were defined as LV mass at least 49.2 g/m2.7 for men and at least 46.7 for women. Relative wall thickness of at least 0.43 identified patients with concentric LV geometry.

RESULTS

Patients with moderate/severe OSA (n = 86) had a higher body mass index and a higher prevalence of paroxysmal atrial fibrillation than those (n = 51) with mild OSA and controls (n = 20). Prevalence of hypertension, diabetes, obesity, LV mass and blood pressure did not differ between the groups. Relative wall thickness was positively related to apnea-hypopnea index (r = 0.30; P = 0.003) and the prevalence of concentric LV geometry was 20% in controls, 12% in mild OSA and 58% in moderate/severe OSA (P < 0.001). In logistic regression analysis concentric LV geometry was associated with moderate/severe OSA [odds ratio (OR) 7.6, P < 0.001], low stress-corrected midwall shortening (OR 3.38, P = 0.004), and higher body mass index (OR 1.09, P = 0.03).

CONCLUSIONS

Moderate/severe OSA is associated with high prevalence of concentric LV geometry. This increased prevalence may in part explain the increased rate of cardiovascular events in these patients.

[Cardiac effects of obstructive sleep apnea]

Sleep disordered breathing, especially obstructive sleep apnea, are common in cardiovascular disease. Negative hemodynamic effects are mediated by nocturnal ischemia and intrathoracal pressure swings. Therefore "therapy resistant" arterial hypertension and congestive heart failure, as well as atrial fibrillation or sleep associated bradycardia are suggestive of sleep disordered breathing. Further on, clinical course of coronary artery disease seems to be influenced by nocturnal breathing disorders. Application of continuous positive airway pressure (CPAP) is effective in most of the patients and attenuates cardiodepressive hemodynamic effects of obstructive sleep apnea.

Cardiac remodeling in obesity

The dramatic increase in the prevalence of obesity and its strong association with cardiovascular disease have resulted in unprecedented interest in understanding the effects of obesity on the cardiovascular system. A consistent, but puzzling clinical observation is that obesity confers an increased susceptibility to the development of cardiac disease, while at the same time affording protection against subsequent mortality (termed the obesity paradox). In this review we focus on evidence available from human and animal model studies and summarize the ways in which obesity can influence structure and function of the heart. We also review current hypotheses regarding mechanisms linking obesity and various aspects of cardiac remodeling. There is currently great interest in the role of adipokines, factors secreted from adipose tissue, and their role in the numerous cardiovascular complications of obesity. Here we focus on the role of leptin and the emerging promise of adiponectin as a cardioprotective agent. The challenge of understanding the association between obesity and heart failure is complicated by the multifaceted interplay between various hemodynamic, metabolic, and other physiological factors that ultimately impact the myocardium. Furthermore, the end result of obesity-associated changes in the myocardial structure and function may vary at distinct stages in the progression of remodeling, may depend on the individual pathophysiology of heart failure, and may even remain undetected for decades before clinical manifestation. Here we summarize our current knowledge of this complex yet intriguing topic.

A preliminary study on the influence of obstructive sleep apnea upon cumulative parasympathetic system activity

OBJECTIVE

Although the autonomic nervous system plays a key role in mediating cardiovascular changes during obstructive sleep apnea (OSA), parasympathetic nervous system (PNS) activity during sleep apnea has not yet been sufficiently investigated. This study is to discuss the relationship between PNS activity and OSA.

METHODS

Polysomnography recording was carried out in 76 patients (71 male and 5 female) with OSA. Cumulative PNS activity during sleep for each patient was derived from time series data of electrocardiogram (ECG) and analyzed by coarse graining spectral analysis of heart rate variability. The correlation between cumulative PNS activity and apnea-hypopnea index (AHI) was then discussed.

RESULTS

Cumulative PNS activity and PNS peaks during sleep were lowly but significantly correlated with OSA severity (r=-0.344, p<0.005; and r=-0.266, p<0.05 respectively), and a linear regression equation could be established. Furthermore, significant correlation was also observed in the adult groups and in the moderate and severe groups, but not in the juvenile and the elderly and mild groups.

CONCLUSION

These findings indicated that PNS function was obviously influenced by OSA during sleep. Cumulative PNS activity level might also serve as a useful parameter for the evaluation of OSA.