The effect of continuous positive airway pressure treatment on blood pressure: a systematic review and meta-analysis of randomized controlled trials

Correlation between apnea-hypopnea index and Tp-Te interval, Tp-Te/QT, and Tp-Te/QTc ratios in obstructive sleep apnea

Background

Obstructive sleep apnea (OSA) is a highly prevalent sleep disorder associated with important cardiovascular complications including ventricular arrhythmias. Tp‐Te interval, Tp‐Te/QT, and Tp‐Te/QTc ratios are repolarization indices representing ventricular arrhythmogenic potential. These parameters are associated with ventricular arrhythmias and sudden cardiac death. The aim of this study was to investigate the correlation between apnea–hypopnea index and Tp‐Te, Tp‐Te/QT, and Tp‐Te/QTc in OSA.

Methods

We screened a total of 280 patients who underwent overnight polysomnography (PSG) between the years 2012–2017 at our institution. Patients were assigned into four groups based on severity of apnea–hypopnea index: 70 with apnea–hypopnea index (AHI) <5 (control group), 71 with 5 ≤ AHI < 15, 63 with 15 ≤ AHI < 30, and 76 with AHI ≥ 30. Tp‐Te, Tp‐Te/QT, and Tp‐Te/QTc were measured.

Results

Compared to control group, repolarization parameters were significantly prolonged in other groups (Tp‐Te interval: 68.3 ± 6.8, 71.8 ± 6.3, 79.1 ± 5.5, and 85.1 ± 6.4 ms, p < .001; Tp‐Te/QT ratio: 167.5 ± 12.7, 181.7 ± 13.0, 202.2 ± 10.0 and 219.4 ± 13.5, p < .001; Tp‐Te/QTc ratio: 151.1 ± 16.6, 167.6 ± 16.6, 193.7 ± 14.4, and 225.5 ± 17.0, p < .001). There was a significant trend toward higher Tp‐Te, Tp‐Te/QT, and Tp‐Te/QTc across higher AHI categories. In a univariate regression analysis, body mass index, smoking status, Tp‐Te, and Tp‐Te/QTc were significantly associated with the severity of AHI in OSA. Tp‐Te (OR 1.629, 95% CI 1.393–1.906, p < .001), Tp‐Te/QTc (OR 1,333 95% CI 1.247–1.424, p < .001), and smoking status (OR 5.771, 95% CI 1.025–32.479, p = .047) were found to be significant independent predictors of severity of AHI in a multivariate analysis, after adjusting for other risk parameters.

Conclusions

Our study showed that Tp‐Te, Tp‐Te/QT, and Tp‐Te/QTc were prolonged in patients with OSA. There was significant correlation between apnea–hypopnea index and these parameters.

Association between Obstructive Sleep Apnea and Exfoliation Syndrome: The Utah Project on Exfoliation Syndrome

PURPOSE

Exfoliation syndrome (XFS), the most common recognizable cause of open-angle glaucoma worldwide, is a systemic disorder with genetic predisposition due to variations in lysyl oxidase-like 1 (LOXL1) function, leading to altered elastin matrices in ocular and systemic tissues. Obstructive sleep apnea (OSA) is a highly prevalent disorder also involving elastic tissue dysfunction and is associated with glaucoma. Because of the similarities between the disorders, we sought to uncover any relationship in the prevalence of these diagnoses.

DESIGN

Case-control, retrospective cohort study.

PARTICIPANTS

A cohort of 81 735 patients diagnosed with OSA at ages 50 to 90 years was identified from medical records from 1996 to 2017 in the Utah Population Database. Case subjects were matched to random controls on sex and birth year in a 4:1 ratio.

METHODS

International Classification of Diseases, Ninth Revision (ICD-9) codes or their Tenth Revision equivalent were used to define a diagnosis of OSA (ICD-9 327.23) and a diagnosis of XFS (ICD-9 365.52 and 366.11). Conditional logistic regression odds ratios (ORs) accounting for individual matching on sex and birth year were used to estimate the risk of XFS in patients with OSA. Models included adjustment for race, obesity, tobacco use, hypertension (HTN), atrial fibrillation (AF), and chronic obstructive pulmonary disease (COPD).

MAIN OUTCOME MEASURE

Whether patients with OSA have an increased risk of diagnosis of XFS compared with controls without OSA.

RESULTS

There was an increased risk of an XFS diagnosis in patients with OSA compared with non-OSA controls (OR, 1.27; 95% confidence interval [CI], 1.02-1.59; P = 0.03). In a stratification of patients by HTN diagnosis history, patients with OSA and HTN exhibited an increased risk of XFS compared with non-OSA controls with HTN (OR, 2.67; 95% CI, 2.06-3.46; P < 0.0001).

CONCLUSIONS

Patients with OSA may be at an increased risk of XFS compared with patients without OSA, particularly in patients with a history of HTN.

Meta-analysis of changes in the levels of catecholamines and blood pressure with continuous positive airway pressure therapy in obstructive sleep apnea

Stress from obstructive sleep apnea (OSA) stimulates catecholamine release consequently exacerbating hypertension. However, different studies have shown a conflicting impact of continuous positive airway pressure (CPAP) treatment in patients with OSA on catecholamine levels and blood pressure. We aimed to examine changes to catecholamine levels and blood pressure in response to CPAP treatment. We conducted a meta‐analysis of data published up to May 2020. The quality of the studies was evaluated using standard tools for assessing the risk of bias. Meta‐analysis was conducted using RevMan (v5.3) and expressed in standardized mean difference (SMD) for catecholamines and mean difference (MD) for systolic (SBP) and diastolic blood pressure (DBP). A total of 38 studies met our search criteria; they consisted of 14 randomized control trials (RCT) totaling 576 participants and 24 prospective cohort studies (PCS) of 547 participants. Mean age ranged between 41 and 62 year and body mass index between 27.2 and 35.1 kg/m². CPAP treatment reduced 24‐hour urinary noradrenaline levels both in RCT (SMD = −1.1; 95% confidence interval (CI): −1.63 to − 0.56) and in PCS (SMD = 0.38 (CI: 0.24 to 0.53). SBP was also reduced by CPAP treatment in RCT (4.8 mmHg; CI: 2.0‐7.7) and in PCS (7.5 mmHg; CI: 3.3‐11.7). DBP was similarly reduced (3.0 mmHg; CI: 1.4‐4.6) and in PCS (5.1 mmHg; CI: 2.3‐8.0). In conclusion, CPAP treatment in patients with OSA reduces catecholamine levels and blood pressure. This suggests that sympathetic activity plays an intermediary role in hypertension associated with OSA‐related stress.

Adaptive servo-ventilation in patients with chronic heart failure and sleep disordered breathing: predictors of usage

PURPOSE

Adaptive servo-ventilation (ASV) is a therapy designed for patients with central sleep apnea (CSA) and Cheyne Stokes respiration. The aim of this study was to find predictors of ASV usage in patients with CSA in a routine sleep clinic cohort.

METHODS

In this retrospective study, consecutive patients in whom ASV therapy was initiated at the University Hospital Regensburg between 2011 and 2015, were analyzed. Analysis included polysomnographies of diagnostic and ASV initiation nights, a phone questionnaire on ASV usage, readout of the ASV device 1 month after initiation ("early ASV usage," 1 month after ASV initiation), and the readout of the last month before a reappointment date set in 2015 ("late ASV usage," median 17 months after ASV initiation).

RESULTS

In 69 consecutive patients, the mean early and late ASV usage per night was 4.8 ± 2.5 h and 4.1 ± 3.0 h, respectively. Seventeen months after initiation, 57% of patients used the device ≥ 4 h per night, and of those 91% reported a subjective benefit from ASV therapy. Early ASV usage was significantly associated with late ASV usage (univariable regression: Beta 0.8, 95%CI [0.6; 1.0] p < 0.001). In multivariable regression analysis, short duration of slow wave sleep (N3) during diagnostic polysomnography (Beta - 6.2, 95%CI [- 11.0; - 1.5]; p = 0.011) and subjective benefit from ASV (Beta 174.0, 95%CI [68.6; 279.5]; p = 0.002) were significantly associated with longer late ASV usage.

CONCLUSION

Early ASV usage predicts late ASV usage. In addition, low slow wave sleep before ASV initiation and subjective benefit from ASV may contribute to higher late ASV usage.

Slow-wave sleep is associated with incident hypertension in patients with obstructive sleep apnea: a cross-sectional study

OBJECTIVE

This study aimed to examine the association between slow-wave sleep ([SWS] N3 stage) and the risk of hypertension in patients with obstructive sleep apnea (OSA) or primary snorers.

METHODS

A retrospective cross-sectional study of 1145 participants who were evaluated for suspected OSA at our Sleep Medical Center were included. Among these participants, 1022 had OSA and 123 were primary snorers. Logistic regression modeling was performed to evaluate the association between the prevalence of hypertension and combined OSA and SWS based on polysomnographic measurements.

RESULTS

Patients with OSA in the lowest SWS quartile (quartile 1,  < 2.0%) showed a two-fold increased risk of hypertension after adjustment for confounding factors compared with primary snorers (odds ratio, 2.13 [95% confidence interval 1.54-2.06]). In logistic analysis stratified according to SWS quartiles, there was no significant difference in the risk of hypertension between patients with OSA and primary snorers in quartile 1. However, in the highest quartile (quartile 4), SWS was significantly associated with incident hypertension in patients with OSA rather than primary snorers.

CONCLUSION

SWS is associated with prevalent hypertension in patients with OSA. Notably, a low proportion of SWS confers a stronger association with incident hypertension than OSA.

Low long-term mortality in patients with sleep apnoea and positive airway pressure therapy: analysis of a large German healthcare database

Background

There are limited data on long-term mortality in sleep apnoea (SA) patients with and without positive airway pressure (PAP) therapy. This retrospective cohort study investigated long-term hospitalisation and mortality rates in SA patients from a German statutory health insurance (SHI) database who did versus did not receive PAP therapy.

Methods

Patients had continuous insurance coverage from 01 January 2008 to 31 December 2013, complete medical records and ≥1 SA-related diagnosis in 2009. Those receiving PAP were matched with a control group not treated with PAP. Outcomes (hospitalisations including stays in the sleep laboratory) were compared between groups the year prior to and the 4 years after SA diagnosis. Mortality was assessed in the 4 years after SA diagnosis.

Results

2176 PAP therapy recipients were matched with 2176 controls. The PAP group had a higher rate of hospitalisation in the year before SA diagnosis than the control group (80.2% vs. 26.6%; p = 0.0016). After diagnosis, the PAP group had a higher hospitalisation rate only in year 1 (p < 0.05), and average length of stay per hospitalisation was lower in the PAP group (p < 0.05 vs. control at years 1, 2 and 4). Cumulative all-cause mortality after year 3 (3.4% vs. 4.6%; p = 0.0287) and after year 4 (4.8% vs. 6.5%; p = 0.0175) was significantly lower in SA patients receiving PAP versus controls (relative risk reduction for death after 4 years: 25.5%).

Conclusion

This real-world cohort study showed an association between long-term PAP therapy use and lower mortality, a higher rate of hospitalisations before and shorter hospital stays after treatment initiation.

Acetazolamide for OSA and Central Sleep Apnea: A Comprehensive Systematic Review and Meta-Analysis

BACKGROUND

Therapy options for OSA and central sleep apnea (CSA) are limited, thus many patients remain untreated. Clinically, acetazolamide is sometimes used for CSA; however, given overlapping pathophysiologic properties of OSA and CSA, we hypothesized that acetazolamide is equally effective for both types. Prior reviews focused on specific subtypes of sleep apnea, study designs, and languages, thus including few studies (typically ≤3) limiting insights.

RESEARCH QUESTION

How efficacious is acetazolamide for sleep apnea, and is its effect modified by sleep apnea type or acetazolamide dose?

STUDY DESIGN AND METHODS

We queried MEDLINE, EMBASE, and ClinicalTrials.gov from inception until March 11, 2019. Any study in which adults with OSA/CSA received oral acetazolamide vs no acetazolamide (control) that reported sleep apnea-related outcomes was eligible, independent of study design or language. Two reviewers independently assessed eligibility and abstracted data. Primary outcomes were apnea-hypopnea index (AHI) and oxygen saturation nadir. Quality of evidence (QoE) was rated with the use of Grades of Recommendation Assessment, Development and Evaluation methods.

RESULTS

We included 28 studies (13 OSA/15 CSA; N_{Subjects,Acetazolamide} = 542; N_{Subjects,Control} = 553) that enabled meta-analyses for 24 outcomes. Acetazolamide doses ranged from 36 to 1000 mg/d and treatment duration from 1 to 90 d (median, 6 d). Overall, acetazolamide vs control lowered the AHI by -0.7 effect sizes (95% CI, -0.83 to -0.58; I² = 0%; moderate QoE) that corresponded to a reduction of 37.7% (95% CI, -44.7 to -31.3) or 13.8/h (95% CI, -16.3 to -11.4; AHI_Control = 36.5/h). The AHI reduction was similar in OSA vs CSA, but significantly greater with higher doses (at least up to 500 mg/d). Furthermore, acetazolamide improved oxygen saturation nadir by +4.4% (95% CI, 2.3 to 6.5; I² = 63%; no evidence of effect modification; very low QoE) and several secondary outcomes that included sleep quality measures and BP (mostly low QoE).

INTERPRETATION

Short-term acetazolamide improved both OSA and CSA. Rigorous studies with long-term follow up are warranted to assess Acetazolamide's value for the chronic treatment of patients with sleep apnea.

CLINICAL TRIAL REGISTRATION

PROSPERO (CRD42019147504).

Prospective association of obstructive sleep apnea risk factors with heart failure and its subtypes in postmenopausal women: The Women's Health Initiative

STUDY OBJECTIVES

The relationship between obstructive sleep apnea (OSA) and heart failure (HF) incidence in postmenopausal women has been understudied, given the limited representation of women in heart failure studies. We investigated the relationship between OSA risk factors and HF and its subtypes in postmenopausal women.

METHODS

We performed a prospective analysis on the adjudicated HF outcomes in the Women's Health Initiative from enrollment (1993-1998) to September 30, 2016. HF with preserved ejection fraction (HFpEF) and reduced ejection fraction (HFrEF) were defined as adjudicated acute HF hospitalization with EF ≥ 45% or < 45%, respectively. We employed Cox regression to examine the association between OSA risk factors and symptoms (individually and using a summary risk score) and time to first hospitalized HF.

RESULTS

Of 42,362 women, 2,205 (5.21%) developed all HF, 1,162 (2.74%) women developed HFpEF, and 679 (1.60%) developed HFrEF. Individual OSA risk factors and symptoms, including obesity (hazard ratio = 1.33, 95% confidence interval [CI] 1.20-1.48), snoring (hazard ratio = 1.30, 95% CI 1.16-1.46), and hypertension (HR = 1.45, 95% CI 1.35-1.56), were positively associated with risk of HF and HFpEF, but only hypertension was associated with HFrEF. When examined as a summary risk score compared with those with none of the OSA risk factors, presence of each additional factor was significantly associated with increased risk of hospitalized HF in a dose-response fashion for HFpEF (P trend < .001), but not HFrEF (P trend = .26).

CONCLUSIONS

OSA risk factors and symptoms were associated with HFpEF, but not HFrEF, among postmenopausal women and are largely dependent on body mass index, snoring, and hypertension.

Association between adherence to continuous positive airway pressure treatment and cost among medicare enrollees

OBJECTIVE

To analyze the cost associated with sleep apnea and effects of continuous positive airway pressure (CPAP) treatment on costs among fee-for-service Medicare beneficiaries.

METHODS

Retrospective cohort design using 5% Medicare claims between 2006 and 2010. Medicare beneficiaries with and without sleep apnea diagnosis between 2007 and 2008 were identified and followed retrospectively for 2 years pre-index-date and 2 years post-index-date. We defined CPAP fill as at least one durable medical equipment claim for CPAP in 6-month period. At least three CPAP fills was defined as "full adherence," and one or two CPAP fills was "partial adherence." We used interrupted time series and generalized linear log-link models to study the association between sleep apnea, CPAP treatment, and costs. To minimize bias, we used propensity score and instrumental variables approach.

RESULTS

Sleep apnea was associated with higher costs (odds ratio [OR] = 1.60; 95% confidence interval [CI] = 1.58, 1.63) compared to those without sleep apnea. Almost half of those with sleep apnea received CPAP treatment. Interrupted time series analysis indicated post level increase in mean monthly cost for full CPAP adherence group, partial CPAP adherence group and no-CPAP group. However, the increase was smallest for the full CPAP adherence group. Full CPAP adherence was associated with lower change in cost (OR = 0.92; 95% CI = 0.88, 0.97) compared to the no-CPAP group.

CONCLUSIONS

Medicare beneficiaries with sleep apnea experience increased cost. Full adherence to CPAP treatment for sleep apnea was associated with lower increase in cost. These findings emphasize the need to effectively identify and treat sleep apnea in Medicare patients.

Leptin: Master Regulator of Biological Functions that Affects Breathing

Obesity is a global epidemic in developed countries accounting for many of the metabolic and cardiorespiratory morbidities that occur in adults. These morbidities include type 2 diabetes, sleep-disordered breathing (SDB), obstructive sleep apnea, chronic intermittent hypoxia, and hypertension. Leptin, produced by adipocytes, is a master regulator of metabolism and of many other biological functions including central and peripheral circuits that control breathing. By binding to receptors on cells and neurons in the brainstem, hypothalamus, and carotid body, leptin links energy and metabolism to breathing. In this comprehensive article, we review the central and peripheral locations of leptin's actions that affect cardiorespiratory responses during health and disease, with a particular focus on obesity, SDB, and its effects during early development. Obesity-induced hyperleptinemia is associated with centrally mediated hypoventilation with decrease CO₂ sensitivity. On the other hand, hyperleptinemia augments peripheral chemoreflexes to hypoxia and induces sympathoexcitation. Thus, "leptin resistance" in obesity is relative. We delineate the circuits responsible for these divergent effects, including signaling pathways. We review the unique effects of leptin during development on organogenesis, feeding behavior, and cardiorespiratory responses, and how undernutrition and overnutrition during critical periods of development can lead to cardiorespiratory comorbidities in adulthood. We conclude with suggestions for future directions to improve our understanding of leptin dysregulation and associated clinical diseases and possible therapeutic targets. Lastly, we briefly discuss the yin and the yang, specifically the contribution of relative adiponectin deficiency in adults with hyperleptinemia to the development of metabolic and cardiovascular disease. © 2020 American Physiological Society. Compr Physiol 10:1047-1083, 2020.

Alternations of Blood Pressure Before and After OSA Surgery

OBJECTIVE

To investigate the changes of blood pressure (BP) on patients with obstructive sleep apnea/hypopnea syndrome (OSA) before and after upper airway surgery.

DESIGN

Case series with chart review.

SETTING

Tertiary academic medical center.

SUBJECTS AND METHODS

Patients with OSA who underwent upper airway surgery were enrolled. We retrospectively investigated the nighttime and daytime BP before and at least 3 months after OSA surgery. Paired t test was used to compare the changes of BP before and after surgery. Generalized estimating equation was used to examine the prognostic significance of the variables in predicting the changes of postoperative BP.

RESULTS

In total, 176 patients with OSA (149 men, 27 women; mean age, 42.9 years; mean apnea/hypopnea index, 43.1/h) were enrolled in this study. The overall nighttime and daytime BP decreased significantly before and after OSA surgery (daytime systolic BP was reduced from 137.3 ± 14.0 mm Hg to 132.7 ± 17.0 mm Hg, P < .01; nighttime systolic BP was reduced from 138.7 ± 16.0 mm Hg to 133.7 ± 15.3 mm Hg, P < .01; daytime diastolic BP was reduced from 87.7 ± 14.7 mm Hg to 84.9 ± 10.6 mm Hg, P = .01; nighttime diastolic BP was reduced from 85.4 ± 12.9 mm Hg to 83.1 ± 11.1 mm Hg, P = .02). The changes of nighttime systolic and diastolic BP were significantly associated with the improvement of percentage of O₂ saturation <90% during polysomnography.

CONCLUSION

Surgical modifications of the upper airways for patients with OSA could benefit blood pressure.

Obesity and cardiovascular disease in women

As the prevalence of obesity continues to grow worldwide, the health and financial burden of obesity-related comorbidities grows too. Cardiovascular disease (CVD) is clearly associated with increased adiposity. Importantly, women are at higher risk of CVD when obese and insulin resistant, in particular at higher risk of developing heart failure with preserved ejection fraction and ischemic heart disease. Increased aldosterone and mineralocorticoid receptor activation, aberrant estrogenic signaling and elevated levels of androgens are among some of the proposed mechanisms explaining the heightened CVD risk. In addition to traditional cardiovascular risk factors, understanding nontraditional risk factors specific to women, like excess weight gain during pregnancy, preeclampsia, gestational diabetes, and menopause are central to designing personalized interventions aimed to curb the epidemic of CVD. In the present review, we examine the available evidence supporting a differential cardiovascular impact of increased adiposity in women compared with men and the proposed pathophysiological mechanisms behind these differences. We also discuss women-specific cardiovascular risk factors associated with obesity and insulin resistance.

Predictors of changes in subjective daytime sleepiness in response to CPAP therapy withdrawal in OSA: A post-hoc analysis

Subjective sleepiness is the hallmark symptom of untreated obstructive sleep apnea (OSA) and leads to an increased risk of motor vehicle accidents and impaired quality of life. Continuous positive airway pressure (CPAP) is the standard therapy for OSA and improves sleepiness. The aim was to identify factors that might predict recurrence of sleepiness in times off CPAP and to define OSA patient types with a likely effect of CPAP on sleepiness. A post-hoc analysis of six clinical trials, including 132 patients with OSA effectively treated with CPAP prior to study inclusion, who were allocated to 2 weeks of CPAP withdrawal, was conducted to assess predictors of a change in subjective sleepiness. A multivariate regression model was used to assess predictors of a change in the Epworth Sleepiness Scale (ESS) score. In response to CPAP withdrawal, the median apnea-hypopnea index (AHI) and the ESS score significantly increased compared to baseline on CPAP by 32.6/hr (95% CI, 28.8, 36.4)/hr and 2.5 (95% CI, 1.8,3.2), respectively (p < .001), in the included 132 patients. There was an independent positive association of AHI (Coef. [95% CI] 0.04 [0.01, 0.08]) with an increase in ESS score upon CPAP withdrawal, and an independent negative association of age (coef. [95% CI], -0.10 [-0.18, -0.2]), ESS on CPAP (coef. [95% CI], -0.21 [-0.40, -0.015]) and active smoking status (coef. [95% CI], -1.22 [-2.26, -0.17]). These findings suggest that younger patients with a low residual sleepiness on CPAP and a recurrence of more severe OSA during CPAP withdrawal are at highest risk of suffering from a clinically relevant return of daytime sleepiness in times off CPAP.

Obstructive Sleep Apnoea Syndrome: Continuous Positive Airway Pressure Therapy for Prevention of Cardiovascular Risk

Obstructive sleep apnoea (OSA) syndrome is characterised by the presence of apnoea or obstructive hypopnoea during sleep, accompanied by hypoxia. It is estimated that the syndrome affects approximately 10% of men and 15% of women. Diagnosis and treatment rates have increased in recent years, but the condition remains undiagnosed in a high percentage of patients. Recent evidence suggests that OSA may increase the risk of cardiovascular disease. The relationship between OSA and cardiovascular disease can be explained, at least in part, by the coexistence of cardiovascular risk factors in the two pathologies, such as age, overweight, smoking and sedentary lifestyle. However, OSA has been independently associated with the risk of developing hypertension, cerebrovascular disease, ischaemic heart disease, heart failure and arrhythmias. Clinical trials that have evaluated the efficacy of continuous positive airway pressure (CPAP) treatment in primary and secondary cardiovascular prevention have not demonstrated a significant reduction in the incidence or recurrence of cardiovascular events. This article analyses the relationship between OSA and cardiovascular risk and discusses recent clinical trials on the efficacy of CPAP in primary and secondary cardiovascular prevention.

Efficacy and adherence of auto-CPAP therapy in patients with obstructive sleep apnea: a prospective study

Introduction

The use of auto-continuous positive airway pressure (auto-CPAP) therapy has been recommended for subjects with moderate-to-severe obstructive sleep apnea (OSA) without significant comorbidities. This study is aimed at evaluating the efficacy and adherence of auto-CPAP therapy in subjects with OSA.

Methods

It was a perspective and descriptive study. All study subjects who had apnea-hypopnea index (AHI) > 30/h, measured by polysomnography, were included. They were treated with auto-CPAP and followed-up for 6 months for evaluating the effect of CPAP-therapy on clinical and biological features and treatment adherence.

Results

One hundred and thirty-nine subjects with severe OSA were accepted for auto-CPAP therapy at inclusion. BMI was 28.4±3.8 kg/m²; neck and abdomen circumferences were 38.2±6.4 and 85.7±11.6. Epworth and Pichot scores were 18.4±6.3 and 28.3±4.5, respectively; AHI was 39±7/h and arousal index was 39±13/h. At 6^th month, 96.4% of study subjects continued to use auto-CPAP-therapy within 6.5±2.4 h/night. There was a significant correlation between the modification (Δ) of Epworth scores and (Δ) AHI after 3 and 6 months of auto-CPAP-therapy (R=0.568 and p=0.003; R=0.745 and p=0.002; respectively). At 6^th month follow up, the main side effects of auto-CPAP were difficult sleeping, dry mouth or nose, skin marks or rashes, discomfort when breathing, and nasal congestion (36.1%, 32.0%, 20.8%, 16.0%, and 11.9%, respectively).

Conclusion

Auto-CPAP is effective in treatment of Vietnamese patients with severe OSA in short term follow up.

Obstructive sleep apnea, hypertension, resistant hypertension and cardiovascular disease

Obstructive sleep apnea (OSA) is one of the most common causes of hypertension (HTN) and cardiovascular disease (CVD). It is also a quite common underlying factor in resistant HTN (RHTN). The main etiological factor of OSA is obesity, which is a rapidly growing global epidemic. To control obesity, patients should be encouraged by health care professionals to lose weight and be educated about weight loss strategies such as lifestyle modifications, which include regular exercise, low-calorie diet, low sodium intake, smoking cessation, and decreased alcohol consumption. This review also emphasizes the importance of screening for OSA as the major underlying cause of essential, and RHTN, which can lead to CVD and can cause end-organ damage. It also stresses the importance of using continuous positive airway pressure (CPAP) and its beneficial effects, along with other antihypertensive regimens, in treating HTN, and RHTN. Treatment with CPAP therapy decreases sympathetic activity, high blood pressure (BP), heart rate, and CVD as well as its associated mortality.

Effects of acupuncture on obstructive sleep apnea severity, blood pressure control and quality of life in patients with hypertension: A randomized controlled trial

Obstructive sleep apnea (OSA) is a common condition among patients with hypertension and treatment with continuous positive airway pressure (CPAP) can decrease blood pressure (BP). However, CPAP is not well tolerated by a significant proportion of patients. The authors investigated the effects of acupuncture on OSA severity and BP control in patients with hypertension. Hypertensive patients with mild to moderate OSA (apnea-hypopnea index, 5-30 events/hr) were randomly assigned to receive acupuncture or sham-acupuncture treatment. Patients were assessed at baseline and after 10 acupuncture sessions using polysomnography, 24-hr ambulatory BP monitoring and a quality of life questionnaire. Forty-four patients (34% men; mean age, 57.0 ± 5.4 years; body mass index, 29.6 ± 3.2 kg/m² ; apnea-hypopnea index, 16.3 ± 6.7 events/hr) completed the study. There were no differences in pre-post-intervention apnea-hypopnea index, daytime or nocturnal BP, or quality of life between the acupuncture and sham-acupuncture groups (p > .05). Acupuncture therapy in hypertensive patients with OSA did not reduce OSA severity, daytime or nocturnal BP, or quality of life.

Non-sleepy obstructive sleep apnoea: to treat or not to treat?

Non-sleepy obstructive sleep apnoea (OSA) is thought to have a prevalence of around 20-25% in industrialised countries. However, the question of whether it should be routinely treated or not is controversial. This review collates the results from recent randomised controlled trials addressing OSA and examines whether treating the condition leads to improvements in quality of life and reduced cardiometabolic dysfunction, comorbidities generally attributed to untreated obstructive sleep apnoea/hypopnoea syndrome.

A meta-analysis of continuous positive airway pressure therapy in prevention of cardiovascular events in patients with obstructive sleep apnoea

Aims

To assess whether continuous positive airway pressure (CPAP) therapy reduces major adverse cardiovascular events (MACE) in patients with moderate-to-severe obstructive sleep apnoea (OSA).

Methods and results

A total of 235 articles were recovered using MEDLINE, EMBASE and Cochrane library (inception-December 2016) and references contained in the identified articles. Seven randomized controlled trials (RCTs) were selected for final analysis. Analysis of 4268 patients demonstrated non-significant 26% relative risk reduction in MACE with CPAP [risk ratio (RR) 0.74; 95% confidence interval (CI) 0.47-1.17; P = 0.19, I2 = 48%]. A series of sensitivity analyses suggested that increased CPAP usage time yielded significant risk reduction in MACE. and stroke. Subgroup analysis revealed that CPAP adherence time ≥4 hours (h)/night reduced the risk of MACE by 57% (RR 0.43; 95% CI 0.23-0.80; P = 0.01, I2 = 0%). CPAP therapy showed no beneficial effect on myocardial infarction (MI), all-cause mortality, atrial fibrillation/flutter (AF), or heart failure (HF) (P > 0.05). CPAP had positive effect on mood and reduced the daytime sleepiness [Epworth Sleepiness Scale (ESS): mean difference (MD) -2.50, 95% CI - 3.62, -1.39; P < 0.001, I2 = 81%].

Conclusion

CPAP therapy might reduce MACE and stroke among subjects with CPAP time exceeding 4 h/night. Additional randomized trials mandating adequate CPAP time adherence are required to confirm this impression.

A randomized controlled trial on ambulatory blood pressure lowering effect of CPAP in patients with obstructive sleep apnea and nocturnal hypertension

Objective: In a randomised controlled trial, we investigated the blood pressure (BP) lowering effect of continuous positive airway pressure (CPAP) in patients with moderate-severe obstructive sleep apnoea syndrome (OSAS, an apnoea-hypopnoea index, AHI of 15 or higher) and nocturnal hypertension (night-time systolic/diastolic BP ≥120/70 mmHg).Methods: Sixty patients were randomly assigned to CPAP or sham CPAP, while maintaining their antihypertensive treatment. Ambulatory BP monitoring was performed at baseline (first run-in visit) and the end of follow-up. Clinic and home BP were measured at baseline and each of the monthly follow-up visits.Results: Of the 60 patients, 47 completed the 3-month study. CPAP (n = 26), compared with sham CPAP (n = 21), slightly and non-significantly reduced 24-h systolic/diastolic BP by -2.8/-2.5 mmHg (p ≥ 0.27), with a slightly greater between-group difference in the daytime (-4.0/-2.8 mmHg, p ≥ 0.29) than night-time (-0.2/-1.5 mmHg, p ≥ 0.50). The CPAP treatment did not significantly influence clinic or home BP during follow-up (p ≥ 0.27). Nonetheless, simple and partial correlation analyses showed that the ambulatory BP lowering effect was dependent on the daytime pulse rate at baseline (r ≥ 0.47, p ≤ 0.01). In patients with a daytime pulse rate greater than 85 beats/min, the mean changes in daytime systolic BP were significantly greater in the CPAP (n = 10) than sham CPAP group (n = 11), with a between-group mean difference of -10.1 mmHg (p = 0.048).Conclusions: The CPAP treatment did not show significant ambulatory BP lowering effect in patients with moderate-severe OSAS and nocturnal hypertension. However, it may be effective in lowering daytime BP in patients with a faster pulse rate.

Resistant/Refractory Hypertension and Sleep Apnoea: Current Knowledge and Future Challenges

Hypertension is one of the most frequent cardiovascular risk factors. The population of hypertensive patients includes some phenotypes whose blood pressure levels are particularly difficult to control, thus putting them at greater cardiovascular risk. This is especially true of so-called resistant hypertension (RH) and refractory hypertension (RfH). Recent findings suggest that the former may be due to an alteration in the renin-angiotensin-aldosterone axis, while the latter seems to be more closely related to sympathetic hyper-activation. Both these pathophysiological mechanisms are also activated in patients with obstructive sleep apnoea (OSA). It is not surprising, therefore, that the prevalence of OSA in RH and RfH patients is very high (as reflected in several studies) and that treatment with continuous positive airway pressure (CPAP) manages to reduce blood pressure levels in a clinically significant way in both these groups of hypertensive patients. It is therefore necessary to incorporate into the multidimensional treatment of patients with RH and RfH (changes in lifestyle, control of obesity and drug treatment) a study of the possible existence of OSA, as this is a potentially treatable disease. There are many questions that remain to be answered, especially regarding the ideal combination of treatment in patients with RH/RfH and OSA (drugs, renal denervation, CPAP treatment) and patients' varying response to CPAP treatment.

Severe obstructive sleep apnea is associated with significant coronary artery plaque burden independent of traditional cardiovascular risk factors

Obstructive Sleep Apnea (OSA) is strongly associated with adverse cardiovascular events. In these patients, increased oxidative stress has been associated with accelerated coronary atherosclerosis. However, it is unclear if OSA is associated with significant coronary artery plaque burden. Our aim is to determine whether OSA and/or markers of hypoxemia are associated with coronary plaque burden (CPB). Patients who had coronary computed tomography angiography (CCTA) and a polysomnogram within 1 year of each other between 2011 and 2016 were analyzed. Apnea-Hypopnea Index (AHI) and hypoxemic burden (ODI3%, ODI4%, nadir SpO2, average spO₂ and time of spO₂ < 88%) were obtained from the polysomnogram. Total CPB was assessed using the prognostically validated CT-Leaman score (CT-LeSc). Significant CPB was defined as CT-LeSc ≥ 8.3. There were 119 patients with mean (± SD) age of 59 ± 12 years. Using logistical regression analysis; AHI, ODI4% and ODI3% were the only parameters associated with significant CPB. Severe OSA (AHI ≥ 30 events/h) was associated with significant CPB with adjusted OR of 3.21 (p = 0.010) independent of traditional cardiovascular risk factors. Mechanisms associated with apnea and hypopnea events (as measured by AHI, ODI3% and ODI4%), but not the severity of arterial desaturation (nadir SpO₂, burden of SpO₂ < 88%) were associated with significant CPB.

Sleep Apnea and Cardiovascular Disease: An Enigmatic Risk Factor

Synchronization of molecular, metabolic, and cardiovascular circadian oscillations is fundamental to human health. Sleep-disordered breathing, which disrupts such temporal congruence, elicits hemodynamic, autonomic, chemical, and inflammatory disturbances with acute and long-term consequences for heart, brain, and circulatory and metabolic function. Sleep apnea afflicts a substantial proportion of adult men and women but is more prevalent in those with established cardiovascular diseases and especially fluid-retaining states. Despite the experimental, epidemiological, observational, and interventional evidence assembled in support of these concepts, this substantial body of work has had relatively modest pragmatic impact, thus far, on the discipline of cardiology. Contemporary estimates of cardiovascular risk still are derived typically from data acquired during wakefulness. The impact of sleep-related breathing disorders rarely is entered into such calculations or integrated into diagnostic disease-specific algorithms or therapeutic recommendations. Reasons for this include absence of apnea-related symptoms in most with cardiovascular disease, impediments to efficient diagnosis at the population level, debate as to target, suboptimal therapies, difficulties mounting large randomized trials of sleep-specific interventions, and the challenging results of those few prospective cardiovascular outcome trials that have been completed and reported. The objectives of this review are to delineate the bidirectional interrelationship between sleep-disordered breathing and cardiovascular disease, consider the findings and implications of observational and randomized trials of treatment, frame the current state of clinical equipoise, identify principal current controversies and potential paths to their resolution, and anticipate future directions.

More Than the Sum of the Respiratory Events: Personalized Medicine Approaches for Obstructive Sleep Apnea

Traditionally, the presence and severity of obstructive sleep apnea (OSA) have been defined by the apnea-hypopnea index (AHI). Continuous positive airway pressure is generally first-line therapy despite low adherence, because it reliably reduces the AHI when used, and the response to other therapies is variable. However, there is growing appreciation that the underlying etiology (i.e., endotype) and clinical manifestation (i.e., phenotype) of OSA in an individual are not well described by the AHI. We define and review the important progress made in understanding and measuring physiological mechanisms (or endotypes) that help define subtypes of OSA and identify the potential use of genetics to further refine disease classification. This more detailed understanding of OSA pathogenesis should influence clinical treatment decisions as well as help inform research priorities and clinical study design. In short, treatments could be individualized on the basis of the underlying cause of OSA; patients could better understand which symptoms and outcomes will respond to OSA treatment and by how much; and researchers could select populations most likely to benefit from specific treatment approaches for OSA.

Acute effects of continuous positive airway pressure in patients with obstructive sleep apnea

Objectives. To enhance the initial compliance of continuous positive airway pressure (CPAP) in the patient with obstructive sleep apnea (OSA), we investigate the acute effects of one-night CPAP on morning blood pressure (BP) and, if any exist, to determine which factors predict BP-lowering effects of one-night CPAP in OSA subgroups stratified by the presence or absence of uncontrolled hypertension. Design. Newly diagnosed OSA patients (a respiratory distress index (RDI) ≥ 15) without a history of hypertension were stratified by the presence or absence of morning hypertension. Comparisons were made of morning BP, overnight change in mean BP (MBP), and circadian BP pattern (R_M/E, the ratio of morning to evening MBP) between two time points of diagnostic and CPAP titrations in each subgroup. In the subgroup with a significantly reduced morning BP, predictors of changes in morning MBP were determined by multiple linear regression analyses. Results. The prevalence of morning hypertension was 48.8%. One-night CPAP reduced BP immediately only in patients with morning hypertension. By contrast, patients without morning hypertension did not experience any BP-lowering effects. In the subgroup with morning hypertension, baseline morning MBP, female sex, and R_M/E were independently associated with reduced morning MBP, and R_M/E was the most important predictor. Conclusions. These results confirm the acute effects of one-night CPAP on lowering BP in OSA patients with morning hypertension. An unfavorable circadian BP pattern is the most important predictor.

Differential blood pressure response to continuous positive airway pressure treatment according to the circadian pattern in hypertensive patients with obstructive sleep apnoea

Continuous positive airway pressure (CPAP) has a heterogeneous effect on blood pressure (BP) in hypertensive patients. However, the effect of CPAP on BP in hypertensive subjects regarding circadian BP pattern has never been explored. This study aimed to assess the effect of CPAP on BP, taking into consideration the circadian BP pattern in untreated hypertensive patients.This study is a post hoc analysis of the Spanish Cohort for the Study of the Effect of CPAP in Hypertension (CEPECTA), a multicentre, randomised trial of CPAP versus sham-CPAP in patients with new-onset systemic hypertension and an apnoea-hypopnoea index >15 events·h^-1 We included patients for whom 24-h ambulatory BP monitoring (ABPM) data were available at baseline and 12 weeks after the intervention. Subjects were classified based on the dipping ratio (dipper/non-dipper). We evaluated the effect of CPAP on ABPM parameters after 12 weeks of treatment.Overall, 272 hypertensive subjects were included in the analysis (113 dippers and 159 non-dippers). Baseline clinical and polysomnographic variables were similar between the groups. CPAP treatment in non-dipper patients was associated with reductions in 24-h ambulatory BP variables and night-time ambulatory BP measurements. However, a nonsignificant effect was reported in the dipper group. The differential effects of CPAP between the groups were -2.99 mmHg (95% CI -5.92-- -0.06 mmHg) for the mean 24-h ambulatory BP and -5.35 mmHg (95% CI -9.01- -1.69 mmHg) for the mean night-time ambulatory BP.Our results show a differential effect of CPAP treatment on BP in hypertensive patients depending on the circadian pattern. Only non-dipper patients benefited from CPAP treatment in terms of BP reduction.

Long term management of obstructive sleep apnea and its comorbidities

Obstructive sleep apnea (OSA) is a worldwide highly prevalent disease associated with systemic consequences, including excessive sleepiness, impairment of neurocognitive function and daytime performance, including driving ability. The long-term sequelae of OSA include and increase risk for cardiovascular, cerebrovascular and metabolic syndrome disorders that ultimately lead to premature death if untreated. To ensure optimal long-term outcomes, the assessment and management of OSA should be personalized with the involvement of the appropriate specialist. Most studies have demonstrated inmediate improvement in daytime somnolence and quality of life with CPAP and other therapies, but the effect of long-term treatment on mortality is still under debate. Currently, the long-term management of OSA should be based on a) identifying physiological or structural abnormalities that are treatable at the time of patient evaluation and b) comprehensive lifestyle interventions, especially weight-loss interventions, which are associated with improvements in OSA severity, cardiometabolic comorbidities, and quality of life. In long-term management, attention should be paid to the clinical changes related to a potential reoccurrence of OSA symptoms and it is also necessary to monitor throughout the follow up how the main associated comorbidities evolve.

Effect of CPAP Treatment of Sleep Apnea on Clinical Prognosis After Ischemic Stroke: An Observational Study

STUDY OBJECTIVES

To evaluate continuous positive airway pressure (CPAP) treatment in patients with moderate to severe sleep-disordered breathing (SDB) after an ischemic stroke.

METHODS

We identified patients included in the Acute Stroke Registry and Analysis of Lausanne (ASTRAL) who underwent polysomnography after an ischemic stroke. We compared patients without significant SDB (apnea-hypopnea index [AHI] < 15 events/h: SDB-), with AHI ≥ 15 events/h who refused CPAP or with poor CPAP adherence (SDB+ CPAP-), and patients with SDB effectively treated by CPAP (SDB+ CPAP+).

RESULTS

We analyzed data from 101 patients (age 68.5 ± 11.1 years, 84.1% men). In multivariate analysis the SDB+ CPAP+ group was associated with a significant reduction of stroke recurrence and mortality (odds ratio 0.13, 95% confidence interval 0.00-0.86, P = .031), whereas atrial fibrillation was independently associated with a higher risk (odds ratio 4.32, 95% confidence interval 1.51-12.33, P = .006). Event-free survival analysis (stroke recurrence and death) after 2-year follow-up showed that those in the SDB+ CPAP+ group had significantly higher cardiovascular survival, and Cox proportion hazard model identified CPAP treatment as significantly associated with survival time (P = .025). The AHI and the National Institutes of Health Stroke Scale subacute score were independently associated with CPAP adherence among patients with SDB.

CONCLUSIONS

This observational study shows that CPAP treatment in stroke patients with moderate to severe SDB is associated with lower rates of stroke recurrence and death.

The Relationship between Obstructive Sleep Apnea and Alzheimer's Disease

Obstructive sleep apnea (OSA) and Alzheimer's disease (AD) are highly prevalent conditions with growing impact on our aging society. While the causes of OSA are now better characterized, the mechanisms underlying AD are still largely unknown, challenging the development of effective treatments. Cognitive impairment, especially affecting attention and executive functions, is a recognized clinical consequence of OSA. A deeper contribution of OSA to AD pathogenesis is now gaining support from several lines of research. OSA is intrinsically associated with disruptions of sleep architecture, intermittent hypoxia and oxidative stress, intrathoracic and hemodynamic changes as well as cardiovascular comorbidities. All of these could increase the risk for AD, rendering OSA as a potential modifiable target for AD prevention. Evidence supporting the relevance of each of these mechanisms for AD risk, as well as a possible effect of AD in OSA expression, will be explored in this review.

The Potential Role of Obstructive Sleep Apnoea in Refractory Hypertension

PURPOSE OF REVIEW

This review seeks to present an overview of the recently found association between refractory hypertension (RfH) and obstructive sleep apnoea (OSA).

RECENT FINDINGS

RfH was recently defined as an extreme phenotype of resistant hypertension characterized by the lack of blood pressure control despite using ≥ 5 antihypertensive drugs at optimal doses. Current data support that the pathophysiological pathway of both types of hypertension is different. The main mechanism involved in resistant hypertension is fluid retention whereas in the case of RfH is the sympathetic over-activity. OSA is now recognized as a cause of hypertension (especially in the case of difficult-to-treat hypertension). It seems that the biological mechanism linking OSA and arterial hypertension is the sympathetic over-activity related to the respiratory events (apnoeas and hypopnoeas) during the night. So, it is not surprising that, although the literature is scarce, some studies have found a very high prevalence of OSA and an excess of sympathetic activity in patients with RfH. Finally, a very recent study demonstrated that continuous positive airway pressure (CPAP) treatment, which controls sympathetic activation in OSA patients, achieves very significant reductions in blood pressure levels in RfH patients, even greater than in those with resistant (non-refractory) hypertension. The prevalence of OSA in patients with RfH is very high. CPAP treatment achieves a clinically significant reduction in blood pressure levels in those patients with RfH (especially in night readings). Patients with RfH must be sent to a sleep unit for a study.

Diurnal changes in central blood pressure and pulse pressure amplification in patients with obstructive sleep apnoea

STUDY OBJECTIVES

Recent evidence suggests that compared to peripheral blood pressure (BP), central BP may be more strongly associated with target organ damage and cardiovascular morbidity and mortality. Technological advances now allow the ambulatory measurement of peripheral and central BP over 24 ​h. For the first time, we set out to characterise the diurnal profile of central BP and pulse pressure amplification (PPA) in patients with obstructive sleep apnoea (OSA).

METHODS

In this observational study, patients with moderate to severe OSA underwent 24 ​h central and peripheral BP testing before and after at least 4 weeks of CPAP therapy. Concurrent actigraphy was performed to confirm sleep and wake times.

RESULTS

36 patients were screened, 31 had successful testing (mean (SD) age 45 ​± ​10 years, AHI 58 ​± ​27 events/hr, Office BP 136/89 ​± ​10.7/9.5 ​mmHg, 32% on anti-hypertensives, 77% dippers), 21 completed testing post CPAP. Central systolic and diastolic BP followed the same nocturnal dipping profile as peripheral BP, however the peripheral pulse pressure (PP) narrowed in sleep (-3.2 ​mmHg, p ​< ​0.001), whereas the central PP remained unchanged (0.124 ​mmHg, NS), causing a significant reduction in PPA overnight (-10.7%, p ​< ​0.001). The magnitude of dip in central systolic pressure was less than peripheral systolic pressure (by 2.3 ​mmHg, p ​< ​0.001). After treatment with CPAP, the PPA reduction overnight was attenuated (by -3.3%, p ​= ​0.004).

CONCLUSIONS

In moderate to severe OSA, central BP and PPA reduce overnight during sleep. Further randomised controlled studies are needed to quantify the differential effects of CPAP and anti-hypertensives on central versus peripheral BP.

Beyond Resistant Hypertension

Obstructive sleep apnea (OSA) is an independent cause of resistant hypertension (RH) but its association with refractory hypertension (RfH), a recently described form of severe hypertension, has not yet been investigated. This study seeks to analyze the association between the presence and severity of OSA/OSA syndrome with RfH and to compare it with a group of patients with OSA/OSA syndrome and RH. We conducted a multicenter, cross-sectional study of consecutive patients diagnosed with RH by means of 24-hour ambulatory blood pressure monitoring. Those patients with blood pressure levels ≥130/80 mm Hg, despite taking at least 5 antihypertensive drugs, were considered to have true RfH. All patients underwent a sleep study and completed a detailed clinical history related to OSA, current medication, and cardiovascular diseases. Overall, 229 patients were included (mean age, 58.3 years; 63% male), of whom 42 (18.3%) satisfied the criteria for RfH. Compared with those with RH, patients with RfH had a higher cardiovascular risk profile, higher blood pressure measurements, and a 2-fold greater risk of having both severe OSA (odds ratio, 2.1, with a prevalence of apnea-hypopnea index ≥15, 95.2% and apnea-hypopnea index ≥30, 64.3%) and OSA syndrome (apnea-hypopnea index ≥5+Epworth Sleepiness Scale >10; odds ratio, 1.9; 52.4% versus 37.3%; P=0.023), as well as higher OSA severity (apnea-hypopnea index, 41.8 versus 33.8 events/h; P=0.026). Patients with RfH had an even greater prevalence and severity of OSA and OSA syndrome than RH patients, highlighting the need to identify these patients to refer them to sleep units on a preferential basis.

Reduction in sympathetic tone in patients with obstructive sleep apnoea: is fixed CPAP more effective than APAP? A randomised, parallel trial protocol

INTRODUCTION

Obstructive sleep apnoea (OSA) is a prevalent disease associated with cardiovascular events. Hypertension is one of the major intermediary mechanisms leading to long-term cardiovascular adverse events. Intermittent hypoxia and hypercapnia associated with nocturnal respiratory events stimulate chemoreflexes, resulting in sympathetic overactivity and blood pressure (BP) elevation. Continuous positive airway pressure (CPAP) is the primary treatment for OSA and induces a small but significant reduction in BP. The use of auto-adjusting positive airway pressure (APAP) has increased in the last years and studies showed different ranges of BP reduction when comparing both modalities. However, the pathophysiological mechanisms implicated are not fully elucidated. Variations in pressure through the night inherent to APAP may induce persistent respiratory efforts and sleep fragmentation that might impair sympathovagal balance during sleep and result in smaller decreases in BP. Therefore, this double-blind randomised controlled trial aims to compare muscle sympathetic nerve activity (MSNA) assessed by microneurography (reference method for measuring sympathetic activity) after 1 month of APAP versus fixed CPAP in treatment-naive OSA patients. This present manuscript describes the design of our study, no results are presented herein. and is registered under the below reference number.

METHODS AND ANALYSIS

Adult subjects with newly diagnosed OSA (Apnoea-Hypopnoea Index >20/hour) will be randomised for treatment with APAP or fixed CPAP. Measurements of sympathetic activity by MSNA, heart rate variability and catecholamines will be obtained at baseline and after 30 days. The primary composite outcome will be the change in sympathetic tone measured by MSNA in bursts/min and bursts/100 heartbeats. Sample size calculation was performed with bilateral assumption. We will use the Student's t-test to compare changes in sympathetic tone between groups.

ETHICS AND DISSEMINATION

The protocol was approved by The French Regional Ethics Committee. The study started in March 2018 with primary completion expected to March 2019. Dissemination plans of the results include presentations at conferences and publication in peer-reviewed journals.

TRIAL REGISTRATION NUMBER

NCT03428516; Pre-results.

Rhinological interventions for obstructive sleep apnoea - a systematic review and descriptive meta-analysis

OBJECTIVES

Obstructive sleep apnoea is a common chronic sleep disorder characterised by collapse of the upper airway during sleep. The nasal airway forms a significant part of the upper airway and any obstruction is thought to have an impact on obstructive sleep apnoea. A systematic review was performed to determine the role of rhinological surgical interventions in the management of obstructive sleep apnoea.

METHODS

A systematic review of current literature was undertaken; studies were included if they involved comparison of a non-surgical and/or non-rhinological surgical intervention with a rhinological surgical intervention for treatment of obstructive sleep apnoea.

RESULTS

Sixteen studies met the selection criteria. The pooled data suggest that there are reductions in the apnoea/hypopnea index and respiratory disturbance index following nasal surgery. However, the current body of studies is too heterogeneous for statistically significant meta-analysis to be conducted.

CONCLUSION

Nasal surgery may have limited benefit for a subset of patients based on current evidence.

Is Maxillomandibular Advancement Associated With Comorbidity Reduction in Patients With Obstructive Sleep Apnea?

PURPOSE

This study investigated whether patients with documented obstructive sleep apnea (OSA) who have a decrease in apnea-hypopnea index (AHI) score and self-reported symptoms after maxillomandibular advancement (MMA) with genial tubercle advancement (GTA) also have a change in their medical comorbidity profile a minimum of 2 years postoperatively. Changes in the quantity of medical diagnoses, quantity of prescription medications, and average weight and body mass index (BMI) were assessed.

PATIENTS AND METHODS

This is a retrospective cohort study of patients with a diagnosis of OSA (AHI score >5 on polysomnogram [PSG]) treated at the Massachusetts General Hospital (Boston, MA) with MMA and GTA from 2001 through 2015. Patients were identified through the oral and maxillofacial surgery patient data registry. Inclusion criteria were the availability of complete clinical records and requisite follow-up time. The primary predictor variable was operative status (preoperative or postoperative). The primary outcome variables were comorbidities reported to be associated with OSA and identified in the authors' previous study (J Oral Maxillofac Surg 76:1999.e1, 2018). Two-tailed paired t tests were used for continuous variables and χ² or Fisher exact tests were used for categorical variables.

RESULTS

Forty-six patients (39 men, 7 women) met the inclusion criteria. Average weight (206.7 ± 42.4 lb preoperatively; 213.8 ± 41.7 lb postoperatively; P = .014) and average BMI (30.0 ± 5.7 kg/m² preoperatively; 30.9 ± 5.3 kg/m² postoperatively; P = .041) significantly increased in patients postoperatively. No meaningful changes in the number of medical diagnoses or number of prescription medications were noted. Stratification of patients by BMI showed significant increases in weight (188.6 ± 21.5 lb preoperatively; 200.1 ± 27.9 lb postoperatively; P = .0085) and BMI (27.1 ± 1.44 kg/m² preoperatively; 28.9 ± 3.52 kg/m² postoperatively; P = .013) only in "overweight" patients. No other parameters were found to be relevant.

CONCLUSIONS

Subjective improvement in OSA symptoms was reported by all patients and objective PSG improvement was reported for 71% of those evaluated. However, no relevant changes in comorbidity profile were found, suggesting that the medical conditions commonly observed with OSA are likely of multifocal etiology.

Predictors of positive airway pressure therapy termination in the first year: analysis of big data from a German homecare provider

Background

There is a lack of robust data about factors predicting continuation (or termination) of positive airway pressure therapy (PAP) for sleep apnea. This analysis of big data from a German homecare provider describes patients treated with PAP, analyzes the therapy termination rate over the first year, and investigates predictive factors for therapy termination.

Methods

Data from a German homecare service provider were analyzed retrospectively. Patients who had started their first PAP therapy between September 2009 and April 2014 were eligible. Patient demographics, therapy start date, and the date of and reason for therapy termination were obtained. At 1 year, patients were classified as having compliance-related therapy termination or remaining on therapy. These groups were compared, and significant predictors of therapy termination determined.

Results

Of 98,329 patients included in the analysis, 11,702 (12%) terminated PAP therapy within the first year (after mean 171 ± 91 days). There was a U-shaped relationship between therapy termination and age; therapy termination was higher in the youngest (< 30 years, 15.5%) and oldest (≥ 80 years, 19.8%) patients, and lower in those aged 50–59 years (9.9%). Therapy termination was significantly more likely in females versus males (hazard ratio 1.48, 95% confidence interval 1.42–1.54), in those with public versus private insurance (1.75, 1.64–1.86) and in patients whose first device was automatically adjusting or fixed-level continuous positive airway pressure versus bilevel or adaptive servo-ventilation (1.28, 1.2–1.38).

Conclusions

This analysis of the largest dataset investigating PAP therapy termination identified a number of predictive factors. These can help health care providers chose the most appropriate PAP modality, identify specific patient phenotypes at higher risk of stopping PAP and target interventions to support ongoing therapy to these groups, as well as allow them to develop a risk stratification tool.

Cardiac rhythm disorders in obstructive sleep apnea

Obstructive sleep apnea (OSA) is common among patients with cardiac rhythm disorders. OSA may contribute to arrhythmias due to acute mechanisms, such as generation of negative intrathoracic pressure during futile efforts to breath, intermittent hypoxia, and surges in sympathetic activity. In addition, OSA may lead to heart remodeling and increases arrhythmia susceptibility. Atrial distension and remodeling, that has been shown to be associated with OSA, is a well-known anatomical substrate for atrial fibrillation (AF). AF is the arrhythmia most commonly described in patients with OSA. Several observational studies have shown that the treatment of OSA with continuous positive airway pressure (CPAP) reduces recurrence of AF after electrical cardioversion and catheter ablation. There is also evidence that nocturnal hypoxemia, a hallmark of OSA, predicts sudden cardiac death (SCD) independently of well-established cardiovascular risk factors. Among patients with an implantable cardiac defibrillator, those with OSA have a higher risk of receiving treatment for life-threatening arrhythmias. Nocturnal hypoxemia may also increase vagal tone, which increases susceptibility to bradycardic and conduction rhythm disorders that have also been described in patients with OSA. In conclusion, there are several biological pathways linking OSA and increased cardiac arrhythmogenesis propensity. However, the independent association is derived from observational studies and the direction of the association still needs clarification due to the lack of large clinical trials. This review focuses on the current scientific evidence linking OSA to cardiac rhythm disorders and point out future directions.