Arousal index as a marker of carotid artery atherosclerosis in patients with obstructive sleep apnea syndrome

Sleep disturbance exacerbates atherosclerosis in type 2 diabetes mellitus

Background

Short sleep duration and poor sleep quality are important risk factors for atherosclerosis. The use of smart bracelets that measure sleep parameters, such as sleep stage, can help determine the effect of sleep quality on lower-extremity atherosclerosis in patients with type 2 diabetes.

Objective

To investigate the correlation between sleep disorders and lower-extremity atherosclerosis in patients with type 2 diabetes.

Methods

After admission, all patients were treated with lower-extremity arterial ultrasound and graded as having diabetic lower-extremity vascular lesions according to the results. A smart bracelet was used to obtain the patient sleep data. The correlation between sleep patterns and diabetic lower-extremity atherosclerosis, diabetic foot, and various metabolic indices was verified.

Results

Between August 2021 and April 2022, we screened 100 patients with type 2 diabetes, with 80 completing sleep monitoring. Univariate ordered logistic regression analysis indicated that patients with a sleep score below 76 (OR = 2.707, 95%CI: 1.127-6.488), shallow sleep duration of 5.3 h or more (OR=3.040, 95 CI: 1.005-9.202), wakefulness at night of 2.6 times or more (OR = 4.112, 95%CI: 1.513-11.174), and a deep sleep continuity score below 70 (OR = 4.141, 95%CI: 2.460-615.674) had greater risk of high-grade lower limb atherosclerosis. Multivariate ordinal logistic regression analysis revealed that the risk of high-grade lower limb atherosclerosis was higher in patients with 2.6 or more instances of nighttime wakefulness (OR = 3.975, 95%CI: 1.297-12.182) compared with those with fewer occurrences. The sleep duration curve of patients with different grades of diabetic lower-extremity atherosclerosis was U-shaped. According to the results of the one-way analysis of variance, the higher the deep sleep continuity score, the lower the Wagner scale score for diabetic foot (P < 0.05).

Conclusions

Sleep disorders (long, shallow sleep duration, frequent wakefulness at night, and poor continuity of deep sleep) can worsen lower limb atherosclerosis in patients with type 2 diabetes. This finding can provide a new method for medical professionals to prevent and treat diabetic lower-extremity vascular lesions.

Sleep Deprivation Promotes Endothelial Inflammation and Atherogenesis by Reducing Exosomal miR-182-5p

BACKGROUND

Insufficient or disrupted sleep increases the risk of cardiovascular disease, including atherosclerosis. However, we know little about the molecular mechanisms by which sleep modulates atherogenesis. This study aimed to explore the potential role of circulating exosomes in endothelial inflammation and atherogenesis under sleep deprivation status and the molecular mechanisms involved.

METHODS

Circulating exosomes were isolated from the plasma of volunteers with or without sleep deprivation and mice subjected to 12-week sleep deprivation or control littermates. miRNA array was performed to determine changes in miRNA expression in circulating exosomes.

RESULTS

Although the total circulating exosome levels did not change significantly, the isolated plasma exosomes from sleep-deprived mice or human were a potent inducer of endothelial inflammation and atherogenesis. Through profiling and functional analysis of the global microRNA in the exosomes, we found miR-182-5p is a key exosomal cargo that mediates the proinflammatory effects of exosomes by upregulation of MYD88 (myeloid differentiation factor 88) and activation of NF-ĸB (nuclear factor kappa-B)/NLRP3 pathway in endothelial cells. Moreover, sleep deprivation or the reduction of melatonin directly decreased the synthesis of miR-182-5p and led to the accumulation of reactive oxygen species in small intestinal epithelium.

CONCLUSIONS

The findings illustrate an important role for circulating exosomes in distant communications, suggesting a new mechanism underlying the link between sleep disorder and cardiovascular disease.

Association between Arousals during Sleep and Subclinical Coronary Atherosclerosis in Patients with Obstructive Sleep Apnea

(1) Aim: We aim to evaluate the association between arousals during sleep and subclinical coronary atherosclerosis detected by coronary computed tomography angiography (CTA) in patients with obstructive sleep apnea (OSA). (2) Methods: This was a cross-sectional study. Consecutive newly diagnosed OSA patients, who underwent coronary CTA examinations within 3 months of the sleep study, were eligible. We used the arousal index (ArI) derived from polysomnography to assess arousals during sleep and a semi-automated plaque quantification software to characterize and quantify the subclinical coronary atherosclerosis. Multiple regression models were used to evaluate the associations of the ArI with the coronary atherosclerotic plaque presence, volume, and composition. (3) Results: A total of 99 patients with OSA were included in the study. In the multivariable models, patients with a high ArI (ArI > 32.2 events/h) were more likely to have coronary plaques compared to those with a low ArI (ArI ≤ 32.2 events/h) (OR: 3.29 [95% CI: 1.284 to 8.427], p = 0.013). Furthermore, the ArI exhibited significant associations with total (β = 0.015), noncalcified (β = 0.015), and low-attenuation (β = 0.012) coronary plaque volume after accounting for established risk factors (p = 0.008, 0.004, and 0.002, respectively). However, no association between the ArI and calcified plaque volume was found. (4) Conclusion: Repetitive arousals during sleep are associated with an increased coronary plaque burden in patients with OSA, which remained robust after adjusting for multiple established cardiovascular risk factors.

Long-term outcomes regarding arterial stiffness and carotid artery atherosclerosis in female patients with rapid eye movement obstructive sleep apnea

Objective

Rapid eye movement (REM) obstructive sleep apnea (OSA) is associated with the risk of cardiovascular events. Arterial stiffness and carotid artery intima-media thickness (IMT) predict these events, but few relevant studies have been conducted. We compared long-term changes in arterial stiffness and IMT between patients with REM OSA and non-REM (NREM) OSA receiving continuous positive airway pressure (CPAP) or oral appliance (OA) therapy.

Methods

Newly diagnosed female patients with OSA received CPAP (n = 6) or OA (n = 7). Pulse wave velocity (PWV) and carotid artery ultrasound were performed before and 60 months after treatment.

Results

There were no differences in baseline characteristics (mean age: 56.0 vs. 61.3 years; mean body mass index: 22.6 vs. 21.7 kg/m²) between the REM OSA and non-REM OSA groups. The median apnea-hypopnea index was lower in the REM OSA group than in the non-REM OSA group. Increased PWV (12.92 ± 1.64 to 14.56 ± 2.73 m/s) and deteriorated glucose metabolism were observed in the REM OSA group after treatment. PWV, IMT, and cardiovascular risk factors were unaffected in the non-REM OSA group.

Conclusion

Arterial stiffness and glucose metabolism are deteriorated in patients with REM OSA compared with these parameters in patients with non-REM OSA after CPAP or OA treatment.

Stroke: What's Sleep Got to Do With It?

SUMMARY

Ischemic strokes most often occur between 6 am and 12 am after awakening from sleep but up to 30% occur during sleep. Wake-up strokes (WUS) are new focal neurological deficit(s) persisting for ≥ 24 hours attributable to an ischemic event present on patient awakening. Obstructive sleep apnea (OSA) is a major risk factor for WUS because it compounds the instability of the morning environment and increases the likelihood of cardiovascular events, including hypertension, atrial fibrillation, right-to-left shunts, and stroke. Circadian-driven alterations in structural, homeostatic, and serological factors also predispose to WUS. Also, WUS patients are often not considered candidates for time-dependent intravenous thrombolysis therapy because of an uncertain onset time. However, using the tissue clock (positive diffusion weighted imaging-negative fluid-attenuated inversion recovery mismatch) dates the WUS as 3 to 4.5 hours old and permits consideration for intravenous thrombolysis and if needed mechanical thrombectomy. Given the high prevalence of moderate/severe OSA in stroke patients and its impact on stroke outcomes, screening with overnight pulse oximetry and home sleep apnea test is needed. Treating OSA poststroke remains challenging. Polysomnographic changes in sleep architecture following acute/subacute stroke may also impact upon stroke outcome.

Respiratory Arousals in Patients with Very Severe Obstructive Sleep Apnea and How They Change after a Non-Framework Surgery

Respiratory arousal is the change from a state of sleep to a state of wakefulness following an apnea or hypopnea. In patients with obstructive sleep apnea (OSA), it could have a helpful role to activate upper airway muscles and the resumption of airflow and an opposing role to contribute to greater ventilatory instability, continue cycling, and likely exacerbate OSA. Patients with very severe OSA (apnea-hypopnea index (AHI) ≥ 60 events/h) may have specific chemical (e.g., possible awake hypercapnic hypoxemia) and mechanical (e.g., restricted dilator muscles) stimuli to initiate a respiratory arousal. Little was reported about how respiratory arousal presents in this distinct subgroup, how it relates to AHI, Epworth Sleepiness Scale (ESS), body mass index (BMI), and oxygen saturation, and how a non-framework surgery may change it. Here, in 27 patients with very severe OSA, we show respiratory arousal index was correlated with each of AHI, mean oxyhemoglobin saturation of pulse oximetry (SpO2), mean desaturation, and desaturation index, but not in BMI or ESS. The mean (53.5 events/h) was higher than other reports with less severe OSAs in the literature. The respiratory arousal index can be reduced by about half (45.3%) after a non-framework multilevel surgery in these patients.

[Arousal characteristics in different OSAHS populations]

Objective:This study sought to explore the effect of age on arousal index in patients with OSAHS, and the significance of arousal index among different phenotypes identified through cluster analysis according to clinical symptoms and complications. Methods:A total of 607 adult patients with OSAHS who received polysomnography in the Second Affiliated Hospital of Xi'an Jiaotong University from July 2020 to July 2021 were selected. All patients registered basic human data, symptoms, complaints and complications, completed the Epworth Sleepiness Scale. We explored the distribution of several PSG parameters in different age groups, and included typical symptoms and complications into cluster analysis to explore the parameter differences in patients with different phenotypes. Results:Young patients had the lowest arousal index and arousal frequency in NREM stage, in middle-aged patients, the arousal index was relatively higher, the arousal times during NREM with oxygen desaturation were the highest. Among elderly patients, the wakefulness after sleep onset（WASO） was the longest, the arousal times in REM sleep was the lowest, and the spontaneous arousal times in NREM sleep were the highest（P<0.05）. Among the 3 types according to the cluster analysis, phenotype Ⅰwas characterised by maximally complications, excessive daytime sleepiness and obesity, while memory and attention impairment were obvious in phenotype Ⅱ. Phenotype Ⅲhad minimal complications, relatively better mental state with shorter time-course of snoring and apnea. Phenotype I differed significantly by higher severity, more severe hypoxemia, higher arousal index and longer WASO time（P<0.05）. Conclusion:the arousal index distribution varies among OSAHS patients with different age, and cluster analysis shows that patients with severe symptoms and more complications tend to have higher arousal index.

Effect of Sleep-Disordered Breathing During Rapid Eye Movement Sleep and Non-Rapid Eye Movement sleep on Acute Ischemic Stroke

OBJECTIVES

Sleep-disordered breathing adversely impacts stroke outcomes. We investigated whether sleep-disordered breathing during rapid eye movement sleep and non-rapid eye movement sleep differentially influenced stroke outcomes.

MATERIALS AND METHODS

Acute ischemic stroke patients who finished polysomnography within 14 days of stroke onset from April 2010 to August 2018 were reviewed. Patients were divided into four groups according to apnea-hypopnea index during rapid eye movement sleep and non-rapid eye movement sleep. The modified Rankin Scale was used to evaluate short-term outcome. During January and April 2019, another follow-up was performed for long-term outcomes, including stroke-specific quality-of-life scale, modified Rankin Scale, stroke recurrence and death.

RESULTS

Of 140 patients reviewed, 109 were finally recruited. Although patients with sleep-disordered breathing during non-rapid eye movement sleep only and with sleep-disordered breathing during both rapid eye movement sleep and non-rapid eye movement sleep had higher apnea-hypopnea indices and more disrupted sleep structures, short-term and long-term outcomes did not significantly different between four groups. In Logistic regression analysis, apnea-hypopnea index (p = 0.013, OR 1.023, 95%CI 1.005-1.042) was found independently associated with short-term outcome. Rapid eye movement sleep latency (p = 0.045, OR 0.994, 95%CI 0.987-1.000) was found independently associated with quality of life. Apnea-hypopnea indices during rapid eye movement sleep or non-rapid eye movement sleep were not significantly associated with short-term or long-term outcomes.

CONCLUSIONS

Apnea-hypopnea index is an independent risk factor of short-term outcome of acute ischemic stroke while sleep-disordered breathing during rapid eye movement sleep and non-rapid eye movement sleep do not affect stroke outcomes differently.

Sleep Fragmentation and Atherosclerosis: is There a Relationship?

Sleep fragmentation refers to the disruption of sleep architecture with poor quality of sleep despite optimal duration of sleep. Sleep fragmentation has been shown to have multiple effects on different body systems. This article reviews the effect of sleep fragmentation on the rate of atherosclerosis which has been linked to comorbidities like myocardial infarction, stroke, and coronary artery disease with an aim to educate patients regarding the importance of sleep hygiene and to incorporate a good amount and quality of sleep as life style modification along with diet and exercise.

Understanding the pathophysiological mechanisms of cardiometabolic complications in obstructive sleep apnoea: towards personalised treatment approaches

In January 2019, a European Respiratory Society research seminar entitled "Targeting the detrimental effects of sleep disturbances and disorders" was held in Dublin, Ireland. It provided the opportunity to critically review the current evidence of pathophysiological responses of sleep disturbances, such as sleep deprivation, sleep fragmentation or circadian misalignment and of abnormalities in physiological gases such as oxygen and carbon dioxide, which occur frequently in respiratory conditions during sleep. A specific emphasis of the seminar was placed on the evaluation of the current state of knowledge of the pathophysiology of cardiovascular and metabolic diseases in obstructive sleep apnoea (OSA). Identification of the detailed mechanisms of these processes is of major importance to the field and this seminar offered an ideal platform to exchange knowledge, and to discuss pitfalls of current models and the design of future collaborative studies. In addition, we debated the limitations of current treatment strategies for cardiometabolic complications in OSA and discussed potentially valuable alternative approaches.

Effect of Nighttime Earplugs and Eye Masks on Sleep Quality in Intensive Care Unit Patients

Purpose

Poor sleep quality in intensive care unit (ICU) can be associated with poor outcome. Excessive noise and lights in ICU are known to disrupt patients’ sleep by causing arousals.

Study design

A prospective randomized controlled study.

Materials and methods

The patients admitted to the medical ICU were prospectively included and randomized to receive earplugs and eye masks or no intervention during their first 5 nights in ICU. Their arousal index and other sleep parameters were measured during the first night by polysomnography. Secondary outcomes including wrist actigraphy profiles and subjective sleep quality were recorded during all study nights.

Results

Seventeen patients were enrolled. Eight patients were randomized to earplugs and eye masks group and nine patients were randomized to control group during their first 5 nights in the ICU. The use of earplugs and eye masks demonstrated the trend toward lower arousal index during the first night (21.15 (14.60) vs 42.10 (18.20) events per hour, p = 0.086) and increased activity index (activity count/hour) (16.12 (7.99) vs 10.84 (10.39) count/hour, p = 0.059) compared to control group. Polysomnography and actigraphy did not demonstrate good agreement.

Conclusion

The use of earplugs and eye masks has a trend toward reduction in arousal index and increased activity in patients admitted to ICU. Limited sample size most likely explained insignificant difference in outcomes. Wrist actigraphy did not accurately measure sleep parameters in ICU patients.

Trial registration

www.clinicaltrials.in.th, TCTR20170727003.

How to cite this article

Arttawejkul P, Reutrakul S, Muntham D, Chirakalwasan N. Effect of Nighttime Earplugs and Eye Masks on Sleep Quality in Intensive Care Unit Patients. Indian J Crit Care Med 2020;24(1):6–10.

Relationship Between Sleep Apnea and Coronary Artery Calcium in Patients With Ischemic Stroke

Study Objectives: Coronary artery disease is considered to be the major cause of death amongst patients with ischemic stroke. The coronary artery calcium (CAC) score is related not only to sleep-disordered breathing, but also with future risk of cardiovascular mortality. We investigated the association between the severity of sleep-disordered breathing and CAC score in patients with ischemic stroke.

Methods: We included 32 patients who underwent coronary multichannel computed tomography and polysomnography (within 2 years of the stroke event) amongst the patients admitted to our clinic due to acute ischemic stroke. We investigated vascular risk factors, polysomnography findings, and sleep questionnaire scores, and their relationships with the CAC score.

Results: All patients were found to have sleep apnea of any degree, and 23 (72%) had severe sleep apnea. Twenty-three (72%) patients had a positive CAC score. Higher CAC scores were associated with elevated respiratory disturbance index (RDI), apnea index, oxygen desaturation index, and STOP-BANG test scores. Multivariate analysis after adjusting for potential confounding factors revealed independent relationships between the CAC score and the RDI (ß [SE] = 5.3 [2.1], p = 0.01), oxygen desaturation index (ß [SE] = 6.8 [2.8], p = 0.02), and STOP-BANG test score (ß [SE] = 90.3 [37.7], p = 0.02).

Conclusion: Our findings indicate a relationship between coronary atherosclerotic burden measured by the CAC score and the severity of sleep apnea. Performing polysomnography could be useful for investigating the severity of hidden coronary artery disease among these patients.