Snoring and severity of symptomatic and asymptomatic carotid stenosis: a population-based study

Snoring severity is associated with carotid vascular remodeling in young adults with overweight and obesity

BACKGROUND

Snoring is often used as a surrogate measure for obstructive sleep apnea (OSA), a sleep disorder associated with cardiovascular disease (CVD) risk. Whether snoring is linked to CVD independent of OSA remains unclear. We aimed to explore the snoring and subclinical CVD association in adults with and without OSA.

METHODS

We conducted a cross-sectional study in 122 overweight/obese participants (24% male; mean age 40.1 years) attending the 24-month follow-up visit of a lifestyle intervention. Using home-based objective measures of sleep-disordered breathing, we stratified participants into 3 snoring/OSA categories using the snoring index (SI), a measure of snoring vibration, and oxygen desaturation index (ODI): (1) OSA (ODI ≥ 5), (2) non-OSA heavy snorer (ODI <5, above-median SI), and (3) non-OSA low snorer (ODI <5, below-median SI). Vascular measures including pulse wave velocity ([PWV]; carotid-femoral [cf], femoral-ankle [fa], brachial-ankle [ba]), carotid intima-media thickness (IMT), and carotid interadventitial diameter (IAD) were compared across snoring/OSA categories. Linear regressions assessed the association between snoring and subclinical CVD independent of traditional CVD risk factors.

RESULTS

Compared to non-OSA low snorers, common carotid IMT and IAD were higher in non-OSA heavy snorers, and faPWV, IMT, and IAD were higher among those with OSA. The difference between non-OSA heavy snorers and low snorers persisted after adjusting for age, race, sex, blood pressure, body mass index, lipids, and insulin resistance (P < .05 for IMT and IAD).

CONCLUSIONS

In overweight/obese young to middle-aged adults, objectively measured snoring was related to vascular remodeling in those without OSA. Snoring may contribute to CVD risk but warrants further examination in larger prospective cohorts.

Sleep-disordered breathing and stroke: chicken or egg?

The bidirectional interaction between sleep-disordered breathing (SDB) and stroke has been the subject of many studies. On the one hand, different forms of SDB, and especially obstructive sleep apnea, increase the risk of stroke either directly or indirectly by influencing other known cardiovascular risk factors such as arterial hypertension and arrhythmias. On the other hand, stroke itself can cause either de novo appearance of SDB, aggravate a pre-existing SDB, or trigger a transition from one type of pathological SDB pattern into another. In this review, we discuss some aspects of this "chicken or egg" relationship.

Association between Snoring and High-Risk Carotid Plaque Features

Objectives Previous studies have demonstrated an association between snoring and carotid disease independent of sleep apnea. The aim of this study was to quantify the association between self-reported snoring and high-risk carotid plaque features on magnetic resonance imaging (MRI) that predict stroke. Study Design Cross-sectional. Setting Tertiary care university hospital and affiliated county hospital. Methods We surveyed 133 subjects with asymptomatic carotid artery disease that had been previously evaluated with high-resolution MRI. The survey captured data on self-reported snoring (exposure) and covariates (age, sex, body mass index, and sleep apnea via the STOP-Bang questionnaire). A subset of patients underwent home sleep apnea testing. High-risk carotid plaque features were identified on the high-resolution MRI and included thin/ruptured fibrous cap and intraplaque hemorrhage (outcomes). We quantified the association between snoring and high-risk carotid plaque features with the chi-square test (unadjusted analysis) and multivariate logistic regression adjusting for the covariates. Results Of 133 subjects surveyed, 61 (46%) responded; 32 (52%) reported snoring. Significantly higher proportions of snorers than nonsnorers had a thin/ruptured fibrous cap (56% vs 25%, P = .01) and intraplaque hemorrhage (63% vs 29%, P < .01). In multivariate analysis, snoring was associated with thin/ruptured fibrous cap (odds ratio, 4.4; 95% CI, 1.1-16.6; P = .04) and intraplaque hemorrhage (odds ratio, 8.2; 95% CI, 2.1-31.6; P < .01) after adjusting for age, sex, body mass index, and sleep apnea. Conclusion This pilot study suggests a significant independent association between snoring and high-risk carotid plaque features on MRI. Further study is warranted to confirm these results in a larger cohort of subjects.

The Relationship between Snoring Sound Intensity and Morning Blood Pressure in Workers

STUDY OBJECTIVES

This study aimed to determine the consequences of snoring independent of obstructive sleep apnea (OSA) and hypothesized that snoring sound intensity, as assessed by mean tracheal sound (TS) energy (Leq), is related to morning blood pressure (BP).

METHODS

A home-based TS monitoring study was performed for two nights on 191 workers in Japan using an IC recorder. Leq and the respiratory disturbance index (RDI) were calculated from the TS data. RDI was used as a marker of OSA severity. Systolic and diastolic BP measurements in the evening and morning (eSBP/eDBP and mSBP/mDBP, respectively) were done before and after TS recording. The data of the second night were analyzed.

RESULTS

Leq was significantly related to both mSBP and mDBP (r = 0.32, p < 0.0001; r = 0.34, p < 0.0001, respectively). Leq was also significantly related to morning BP after adjustment for age, sex, and body mass index. However, the relationship was no longer significant when both RDI and Leq were included in the multiple regression model. In non-apneic, non-obese subjects, Leq was significantly related to both mSBP and mDBP (r = 0.38, p < 0.0001; r = 0.33, p = 0.0004, respectively). In this group, Leq was associated with mSBP after adjusting for all confounding factors (n = 106, p = 0.022).

CONCLUSIONS

The association between night TS intensity and morning BP suggests a pathological role of heavy snoring. To understand this association, a prospective cohort study in a general population is warranted.

COMMENTARY

A commentary on this article appears in this issue on page 1581.

Management of severe obstructive sleep apnea using mandibular advancement devices with auto continuous positive airway pressures

The use of continuous positive airway pressures (CPAP) is considered standard treatment of moderate to severe obstructive sleep apnea (OSA). Treatment of the disease poses a great challenge not only for its diagnostic purpose but also for its treatment part. In about 29-83% of the patients, treatment is difficult because of non-compliance resulting due to high pressures, air leaks and other related issues. In such situations, alternative methods of treatment need to be looked for so as to ascertain better management. Mandibular advancement devices along with CPAP may show better treatment outcome in specific situations.

Snoring amplifies the risk of heart failure and mortality in dialysis patients

BACKGROUND

Snoring, an indicator of sleep-disordered breathing (SDB), associates with all-cause and cardiovascular (CV) mortality in high-risk conditions such as chronic heart failure (HF). Because SDB and HF are exceedingly frequent in end-stage kidney disease (ESKD), we hypothesized that SDB as detected by snoring may impact upon the relationship between chronic HF and all-cause and CV mortality in these patients.

METHODS

We tested this hypothesis in a cohort of 827 ESKD patients, followed up for 2.3 years.

RESULTS

In this population, snoring was a strong modifier of the risk of chronic HF for all-cause and CV death. In fully adjusted Cox models, the hazard ratio (HR) associated to chronic HF for the study outcomes was highest in heavy snorers [all-cause death: HR 2.6 (95% CI 1.6-4.3, p < 0.001); CV death: HR 4.0 (95% CI 2.1-7.6, p < 0.001)], intermediate in moderate snorers [all-cause death: HR 1.6 (95% CI 1.1-2.2, p = 0.01); CV death: HR 1.8 (95% CI 1.2-2.8, p = 0.01)], and lowest and not significant in non-snorers [all-cause death: HR 0.9 (95% CI 0.6-1.6, p = NS); CV death: HR 0.8 (95% CI 0.4-1.6, p = NS)].

CONCLUSIONS

Snoring is a strong and independent effect modifier of the relationship between chronic HF and all-cause and CV mortality in ESKD. Since SDB and snoring are in part attributable to reversible pharyngeal oedema, intensified surveillance and treatment of chronic HF snorers on dialysis may translate into better clinical outcomes in this very high-risk population, an issue which remains to be tested in specifically designed clinical trials.

The effect of obstructive sleep apnea syndrome and snoring severity to intima-media thickening of carotid artery

INTRODUCTION

Intima-media thickening (IMT), which is the early finding of carotid artery atherosclerosis, has been shown to be associated with obstructive sleep apnea syndrome (OSAS). In our study, we aimed to assess prospectively the effect of severity of OSAS and snoring on carotid artery IMT.

METHODS

A total of 102 patients who were admitted to sleep laboratory between May 2011 and May 2012 were included in the study. All patients were examined by polysomnography. Common carotid arteries (CCA) and internal carotid arteries (ICA) were evaluated for IMT by carotid Doppler ultrasonography.

RESULTS

The mean age was 45.9 ± 11.1, with 40 (39.2 %) women and 62 (60.8 %) men. Of 88 OSAS patients who had an apnea-hypopnea index (AHI) of >5, 33 (37.5 %) had mild, 20 (22.7 %) had moderate, and 35 (39.8 %) had severe disease. Fourteen patients who had AHI <5 were designated as the habitual snoring group. IMT was detected in 17 (16.7 %) of all patients. In patients with severe OSAS, CCA walls were thicker (p = 0.040) and IMT ratios were higher (p = 0.019) compared to mild/moderate OSAS patients. In patients with IMT, age, AHI, oxygen desaturation index (ODI), and snoring index were higher compared to patients without IMT (p < 0.05).

CONCLUSION

Carotid artery IMT, which is an early finding of atherosclerosis, was found to be highly correlated with OSAS and snoring severity.

Mean tracheal sound energy during sleep is related to daytime blood pressure

STUDY OBJECTIVES

The pathological role of snoring independent of obstructive sleep apnea remains under debate. The authors hypothesized that snoring sound intensity, as assessed by mean tracheal sound energy (Leq) during sleep, is related to daytime blood pressure.

DESIGN

Retrospective analysis of clinical records and polysomnography data.

SETTING

Sleep laboratory at a national hospital in Japan.

PATIENTS

Consecutive patients who underwent diagnostic polysomnography with suspicion of sleep apnea between January 2005 and December 2009 (n = 1,118).

INTERVENTIONS

Not applicable.

MEASUREMENTS AND RESULTS

Leq was calculated from tracheal sound spectra recorded every 0.2 sec during polysomnography. Daytime high blood pressure (HBP) was defined as taking antihypertensive drugs or having a systolic blood pressure ≥ 140 mm Hg or a diastolic blood pressure ≥ 90 mmHg at the patient's first clinical visit. Patient age, sex, body mass index, apnea-hypopnea index, alcohol consumption, and smoking were considered as confounders. Leq during sleep was associated with HBP after adjusting for all confounding factors (n = 1,074, P = 0.00019). This association was demonstrated even in nonapneic nonobese patients (n = 232, P = 0.012).

CONCLUSIONS

The association between snoring intensity, as assessed by mean sound energy, and blood pressure suggests a pathological role for heavy snoring. Further study in a general population is warranted.

The relationship between cephalometric carotid artery calcification and Framingham Risk Score profile in patients with obstructive sleep apnea

PURPOSE

The morbidity rate of arteriosclerosis becomes clinically manifested as acute cardiovascular events. In the progress of atherosclerosis, the carotid artery calcifies and sometimes appears as a calcified mass on a cephalometric radiograph. This study was designed to evaluate cardiovascular risks according to the Framingham Risk Score (FRS) between subjects with and without visible carotid artery calcification on a cephalogram.

METHODS

Subjects diagnosed with obstructive sleep apnea (OSA) were divided into two groups according to whether or not calcification was visible on a cephalometric radiograph in the carotid artery area, and the characteristic differences between the two groups were analyzed. The evaluated variables included age, BMI, apnea-hypopnea index (AHI), SpO2, ESS, blood pressure, medication history, diabetes mellitus (DM), drinking, smoking, and lipid-related measurements. FRSs for stroke, general cardiovascular disease (GCD), and coronary heart disease (CHD) were calculated. Statistical analyses were performed (SPSS 18.0) with significance defined as a two-tailed p value less than 0.05.

RESULTS

A total of 811 subjects completed the data collection (727 males, age 53.0 ± 12.5 years, AHI 31.7 ± 22.6, times/h). From FRSs, probabilities of a GCD, stroke, and CHD within 10 years were 16.0 ± 9.7, 9.8 ± 6.7, and 11.9 ± 8.3 %, respectively. Some 84 subjects exhibited calcification in the carotid arterial area. Calcification subjects were higher GCD risk and older than subjects who had no identified calcification (20.3 ± 10.1 vs 15.6 ± 20.3 %, p = 0.013, 58.8 ± 11.4 vs. 52.3 ± 12.5 years, p < 0.001). Although there is no significant difference in OSA-related variables and FRSs, subjects with visible calcifications have higher prevalence of high blood pressure medication and DM (p < 0.01).

CONCLUSION

While the presence of a calcified mass on a cephalometric radiograph is not diagnostic of atherosclerosis, this information indicates some cardiovascular risk.