Influence of the severity of obstructive sleep apnea on heart rate

Combined Airway and Bariatric Surgery (CABS) for Obstructive Sleep Apnea Patients with Morbid Obesity: A Comprehensive Alternative Preliminary Study

Although continuous positive airway pressure is the gold standard for obstructive sleep apnea (OSA), it does not improve obesity. By contrast, bariatric surgery significantly improves obesity but with sustained OSA in the majority of patients. This study proposes a comprehensive technique—combined airway and bariatric surgery (CABS)—to improve both obesity and OSA. The aims of the study are to evaluate the feasibility, safety and efficacy of CABS in morbidly obese OSA patients. The retrospective study enrolled 20 morbidly obese OSA patients (13 males; median age, 44 years; median apnea−hypopnea index (AHI), 63.2 event/h; median body mass index (BMI), 41.4 kg/m2). The study population was divided into two groups based on patients’ volition after shared decision making. The bariatric surgery (BS) group included laparoscopic sleeve gastrectomy (LSG, n = 8) and laparoscopic Roux-en-Y gastric bypass (LRYGB, n = 2). CABS involved bariatric surgery—LSG (n = 8) and LRYGB (n = 2) in conjunction with airway surgery (concurrent nasal/palatal/lingual surgery [n = 8], concurrent palatal/lingual surgery [n = 2]). Patients received a home sleep apnea test at baseline and one year after surgery. The two patient groups were not different in age, sex, preoperative AHI or preoperative BMI. There was no airway compromise, wound bleeding or infection throughout the postoperative period. One year after surgery, patients in both groups achieved significant improvement in AHI and BMI. Furthermore, the improvement in AHI was significantly higher (p = 0.04) in the CABS group than in the BS group despite the insignificant change in BMI reduction (p = 0.63) between the two groups. In the CABS group, the BMI dropped from 40.4 to 28.4 kg/m2 (p < 0.0001) and the AHI decreased from 75.1 to 4.5 event/h (p = 0.0004). The classic success rate for OSA was 90% and the cure rate was 60% in the CABS group. A perioperative assessment of CABS group patients also revealed a significant improvement in the Epworth sleepiness scale, minimal O2 saturation, snoring index and heart rate. CABS is feasible and safe in treating OSA with morbid obesity. CABS achieves more reduction in AHI than BS alone with high success and cure rates for OSA. CABS can also significantly improve quality of life and general health and offers a comprehensive alternative for morbidly obese OSA patients.

Racial disparities in sleep-related cardiac function in young, healthy adults: Implications for cardiovascular-related health

STUDY OBJECTIVES

Considerable evidence shows that individuals from marginalized racial/ethnic groups in the US experience greater rates of sleep disturbance and cardiovascular complications. Because sleep is a modifiable factor that is critically involved in cardiovascular health, improved understanding of the association between sleep and cardiovascular health during early adulthood can prevent cardiovascular disparities. This study examined racial/ethnic differences in cardiovascular function during sleep using heart-rate and heart-rate-variability analyses.

METHODS

Participants in this laboratory-based sleep study included healthy, "good sleepers" who were in early adulthood and resided in the US at the time of participation [14 non-Hispanic Black (NHB; age=30.9(6.6), 57% female), 12 Asian (Asian, age=26.0(5.2), 42% female), and 24 non-Hispanic white (NHW; age=24.6(5.8), 79% female)].

RESULTS

After adjusting for demographic factors and an apnea-hypopnea index, we found significantly higher heart rate within NREM Stage 2 (N2) (b=-22.6, p=.04) and REM sleep (b=-25.8, p=.048) and lower heart rate variability during N2 sleep (b=-22.6, p=.04) among NHB individuals compared to NHW individuals. Further, NHB and Asian participants demonstrated significantly lower percent of time in slow wave sleep (SWS) compared to NHW participants (NHB: b=-22.6, p=.04; Asian: b=-22.6, p=.04). Individuals' percent of time in SWS significantly mediated differences in heart rate during N2 [indirect=0.94, 95% CI (0.03, 2.68)] and REM sleep [indirect=1.02, 95% CI (0.04, 3.04)].

CONCLUSIONS

Our results showed disparities in sleep-related cardiovascular function in early adulthood that are mediated by SWS. These data suggest targeting sleep health in early adulthood might help reduce cardiovascular disease burden on individuals from marginalized groups.

Increased heart rate with sleep disordered breathing in hypertrophic cardiomyopathy

BACKGROUND

Current guidelines recommend medications with rate control properties for symptomatic patients with hypertrophic cardiomyopathy (HCM) based on the rationale that lowering heart rate (HR) improves their symptoms. Whether sleep disordered breathing (SDB) is associated with increased HR in HCM patients is not known.

METHOD

We diagnosed uncontrolled SDB (oxygen desaturation index ≥5) in consecutive echocardiographically confirmed HCM patients seen at Mayo Clinic, Rochester, and analyzed their HR as recorded by a 24-h Holter monitor. We compared mean, minimum, maximum HR between those with vs without SDB. In a pilot subanalysis of HCM patients with SDB who also underwent subsequent diagnostic polysomnography (PSG), we analyzed RR interval changes coinciding with obstructive sleep apnea and hypopnea episodes.

RESULTS

Of the 230 HCM patients included in this study (age 54 ± 16 years; 138 male; LVOT pressure gradient at rest 45 ± 39 mmHg), 115 (50%) patients had SDB. HCM patients with SDB were recorded to have higher mean HR (71 vs. 67 bpm; p = .002, adjusted p = .001), and this difference was most pronounced during night hours of 10 PM to 5 AM (61 vs. 67 bpm; p < .001). In the pilot analysis of the available PSG data, the release of obstructive sleep apneas and hypopneas coincided with fluctuation of HR.

CONCLUSIONS

SDB is independently associated with higher mean HR in patients with HCM, and this difference is most significant during sleep. Treatment of SDB, which is readily available, should be tested as a complementary modality to the currently recommended pharmacotherapy aimed at lowering HR in patients with symptomatic HCM.

A Non-Framework Multilevel Surgery May Reduce Mean Heart Rate in Patients with Very Severe Obstructive Apnea Having Confined Retroglossal Space and Framework

An elevated mean heart rate in untreated patients of obstructive sleep apnea (OSA) may lead to a higher risk of mortality and the development of various cardiovascular diseases. The elevation may positively relate to the severity of OSA and present in both wakefulness and sleep. A reduction in heart rate has been presented in reports of treating OSA patients with continuous positive airway pressure (CPAP). However, patients with very severe OSA may refuse use of CPAP devices and advocated surgeries, such as direct skeletal surgery or tracheostomy. It is unclear whether the non-framework multilevel surgery we reported previously can overcome the unfavorable anatomy and reduce mean heart rate, which serves as a risk factor of mortality. Here, we show that multilevel surgery reduced the mean heart rate from 68.6 to 62.7 with a mean reduction of 5.9 beats/min. The results suggest that the surgery may reduce the risk of consequences and mortality associated with an elevated mean heart rate, such as various cardiovascular diseases. We disclose these findings, along with the variations and possible risks to our future patients with very severe OSA who refuse or cannot use a CPAP device or reject direct skeletal surgery.

Longitudinal effect of nocturnal R-R intervals changes on cardiovascular outcome in a community-based cohort

RATIONALE

Sleep-disordered breathing (SDB) is strongly linked to adverse cardiovascular outcomes (cardiovascular diseases (CVD)). Whether heart rate changes measured by nocturnal R-R interval (RRI) dips (RRI dip index (RRDI)) adversely affect the CVD outcomes is unknown.

OBJECTIVES

To test whether nocturnal RRDI predicts CVD incidence and mortality in the Wisconsin Sleep Cohort study (WSCS), independent of the known effects of SDB on beat-to-beat variability.

METHODS

The study analysed electrocardiograph obtained from polysomnography study to assess the nocturnal total RRDI (the number of RRI dips divided by the total recording time) and sleep RRDI (the number of RRI dips divided by total sleep time). A composite CVD risk as a function of total and sleep RRDI was estimated by Cox proportional hazards in the WSCS.

RESULTS

The study sample consisted of 569 participants from the WSCS with no prior CVD at baseline were followed up for up to 15 years. Nocturnal total RRDI (10-unit change) was associated with composite CVD event(s) (HR, 1.24 per 10-unit increment in RRDI (95% CI 1.10 to 1.39), p<0.001). After adjusting for demographic factors (age 58±8 years old; 53% male; and body mass index 31±7 kg/m²), and apnoea-hypopnoea index (AHI 4%), individuals with highest total nocturnal RRDI category (≥28 vs<15 dips/hour) had a significant HR for increased incidence of CVD and mortality of 7.4(95% CI 1.97 to 27.7), p=0.003). Sleep RRDI was significantly associated with new-onset CVD event(s) (HR, 1.21 per 10-unit increment in RRDI (95% CI 1.09 to 1.35), p<0.001) which remained significant after adjusting for demographic factors, AHI 4%, hypoxemia and other comorbidities.

CONCLUSION

Increased nocturnal RRDI predicts cardiovascular mortality and morbidity, independent of the known effects of SDB on beat-to-beat variability. The frequency of RRDI is higher in men than in women, and is significantly associated with new-onset CVD event(s) in men but not in women.

Abnormal respiratory event detection in sleep: A prescreening system with smart wearables

Sleeping is an important activity to monitor since it has a crucial role in the overall health and well-being of the people and society. In order to diagnose the problems in sleep, different monitoring systems are developed in the literature. The unobtrusiveness, reduced cost, objectiveness, protection of privacy and user-friendliness are the main design considerations and the proposed system design achieves those objectives by utilizing smart wearables, smart watch and smart phone. The accelerometer and heart rate monitor sensors on smart watch and the sound level sensor on the smart phone are activated. The experiments with this system are performed with 17 subjects in a sleep clinic. The data collected from these subjects is used to generate various combinations by employing varied feature extraction, feature selection and sampling approaches. Five different machine learning algorithms are implemented and the classification results are generated using the various combinations of data, training and scoring strategies. The system performance is measured in two ways, the accuracy rate of distinguishing abnormal respiratory events is 85.95% and the classification success of subjects according to the problems in their respiration is one misclassification among 17 subjects. With all the methodology utilized in this study, the proposed system is a novel prescreening tool which recognizes the severity of problems in respiration during sleep.

Obstructive sleep apnea is associated with increased QT corrected interval dispersion: the effects of continuous positive airway pressure

Introduction

Severe obstructive sleep apnea is associated with increased QT corrected interval dispersion and continuous positive airway pressure is thought to improve this arrhythmogenic marker.

Objective

The aim of the study was to determine the decrease of ratio of cardiovascular risk in patients with obstructive sleep apnea.

Methods

The study included 65 patients with severe obstructive sleep apnea who had an apnea-hypopnea index score of >30. Each patient underwent 12-channel electrocardiogram monitoring and polysomnography. Patients with an apnea-hypopnea index score of <5 were used as the control group. The control group also underwent electrocardiogram monitoring and polysomnography testing. The QT corrected interval dispersion levels of both groups were calculated. Three months after continuous positive airway pressure treatment, electrocardiogram recordings were obtained from the 65 patients with severe obstructive sleep apnea again, and their QT corrected interval dispersion values were calculated.

Results

There were 44 male and 21 female patients with severe obstructive sleep apnea syndrome. The age, gender, body mass index, initial saturation, minimum saturation, average saturation, and desaturation index were determined in both groups. The QT corrected intervals of the obstructive sleep apnea patients (62.48 ± 16.29 ms) were significantly higher (p = 0.001) than those of the control group (29.72 ± 6.30 ms). There were statistically significant differences between the QT corrected values before and after the continuous positive airway pressure treatment, with pretreatment QT corrected intervals of 62.48 ± 16.29 ms and 3-month post-treatment values of 41.42 ± 16.96 ms (p = 0.001). There was a positive and significant correlation between QT corrected interval dispersion periods and the apnea-hypopnea index and hypopnea index in obstructive sleep apnea patients (p = 0.001; r = 0.71; p = 0.001; r = 0.679, respectively).

Conclusion

Continuous positive airway pressure treatment reduced the QT corrected interval dispersion in patients with severe obstructive sleep apnea. In addition, shortening the QT corrected interval dispersion periods in patients with severe obstructive sleep apnea may reduce their risk of arrhythmias and cardiovascular disease.

Systolic Blood Pressure Elevation in Children with Obstructive Sleep Apnea Is Improved with Positive Airway Pressure Use

INTRODUCTION

To evaluate the effect of continuous positive airway pressure (CPAP) treatment on blood pressure (BP) in children with obstructive sleep apnea (OSA).

STUDY DESIGN

Retrospective chart review of children aged 7-17 referred to Benioff Children's Hospital Oakland for the evaluation of snoring. Data collected included age, body mass index (BMI), BP, heart rate, apnea-hypopnea index, and oxygen saturation nadir. Children were divided into 3 groups: snorers, untreated OSA, and OSA treated with CPAP. Seventy-five children were identified, 25 in each group.

RESULTS

There was no difference in age or apnea-hypopnea index among the groups. The CPAP group had higher BMI than the snorers and untreated OSA groups. Systolic BP was higher in the 2 OSA groups compared with the snorers. After CPAP treatment, systolic BP decreased. The BP decrease was significantly greater in patients with higher BMI at baseline. There was no significant change in diastolic BP in the 3 groups.

CONCLUSION

Children with OSA have higher systolic BP than habitual snorers. Treatment with CPAP in children with OSA for 6 months reduced their systolic BP despite a small increase in their BMI.

Nocturnal pulse rate and symptomatic response in patients with obstructive sleep apnoea treated with continuous positive airway pressure for one year

BACKGROUND

Obstructive sleep apnoea (OSA) is the most common form of sleep-disordered breathing and a known risk factor for cardiovascular disease. We hypothesised that in patients with OSA the characteristics of nocturnal pulse rate (PR) are associated with changes in blood pressure and daytime sleepiness, following commencement of continuous positive airway pressure (CPAP) therapy.

METHODS

Pulse oximetry data, demographics, daytime sleepiness and blood pressure were recorded at baseline and at one year follow up. Patients with OSA were grouped according to positive and negative changes in the PR (ΔPR) response during the first night of pulse oximetry before commencement of CPAP.

RESULTS

A total of 115 patients (58 with OSA and 57 matched subjects without OSA) were identified and included in the analysis. The scale of improvement in daytime sleepiness could be predicted by a negative or positive ΔPR, as recorded in the initial screening pulse oximetry [ΔESS -5.8 (5.1) vs. -0.8 (7.2) points, P<0.05]. A negative correlation was observed between mean nocturnal PR and changes in systolic blood pressure (SBP) after one year of CPAP treatment (r=-0.42, P<0.05).

CONCLUSIONS

Mean nocturnal PR prior to CPAP initiation was associated with changes in SBP at one year follow up. A descending nocturnal PR in patients with OSA, prior to CPAP initiation, might help to identify a symptomatic response from long term CPAP treatment.

Arrhythmia and sleep-disordered breathing in patients undergoing cardiac surgery

BACKGROUND

Recently, the role of sleep-disordered breathing (SDB) in cardiovascular disease has attracted attention. In this study, we investigated the influence of SDB on postoperative arrhythmias after cardiac surgery.

METHODS AND RESULTS

In 89 patients undergoing cardiac surgery, postoperative portable monitoring for SDB and Holter electrocardiography were performed. The primary end-points were the apnea-hypopnea index (AHI) and occurrence of arrhythmia. The secondary end-points were: (1) patient background factors; (2) average heart rate; (3) maximum heart rate (total, daytime, and nighttime); (4) minimum heart rate (total, daytime, and nighttime); (5) minimum SaO(2) during sleep; and (6) an independent predictor for arrhythmia. Twenty-six patients (29.2%) had an AHI≥15 and they were classified into the SDB group, while patients with an AHI<15 formed the non-SDB group (70.8%). Although there was no significant difference in atrial fibrillation, frequent nocturnal premature ventricular contractions were significantly more common in the SDB group (19.2%) than the non-SDB group (3.2%) (p=0.01). Maximum daytime and nighttime heart rates were also significantly higher in the SDB group. AHI was a significant predictor for frequent nocturnal premature ventricular contractions.

CONCLUSIONS

This study showed that SDB is common among patients undergoing cardiac surgery, and that SDB might be closely associated with arrhythmia in these patients.