Respiratory Disturbance Index Values Research Articles

Influence of obesity and overweight on the association between sleep-disordered breathing and atrial fibrillation: the DASAP-HF study

Abstract Background The association between sleep apnea (SA) and atrial fibrillation (AF) has been well described. However, it remains unclear whether the association is causative or primarily dependent on shared comorbidities such as obesity. The Respiratory Disturbance Index (RDI) computed by an implantable cardioverter defibrillator (ICD) algorithm accurately identifies severe SA, whether central or obstructive in origin. Purpose In the present analysis we studied in patients with heart failure the contribution of obesity in the relationship between SA, measured by RDI, and AF. Methods Patients with ejection fraction ≤35% implanted with an ICD endowed with an algorithm (ApneaScan) that calculates the RDI each night, were enrolled and followed-up for 24 months. The weekly mean RDI value was considered, as calculated during the entire follow-up period. The endpoint was daily AF burden of ≥6 hours. Results 164 patients (age 67±10 years, 75% male, ejection fraction 29±5%) had usable RDI values during the entire follow-up period. Body mass index (BMI) was <25 kg/m2 in 62 patients (normal), 25.0–29.9 kg/m2 in 66 patients (overweight), ≥ 30 kg/m2 in 36 patients (obese). When compared with normal patients (31±11 episodes/h), the average RDI value calculated during the entire follow-up period did not differ in overweight patients (35±13 episodes/h, p=0.114), but was significantly higher in obese patients (39±12 episodes/h, p=0.002). During follow-up, AF burden ≥6 hours/day was documented in 48 (29%) patients (BMI ≥ versus <25 kg/m2; HR: 1.47, 95% CI: 0.83–2.60, p=0.197; BMI ≥ versus <30 kg/m2; HR: 0.98, 95% CI: 0.46–2.09, p=0.963). Based on the ROC curve analysis, average RDI ≥37 episodes/h maximized sensitivity and specificity for the prediction of AF (Area under the curve: 0.63, 95% CI: 0.55–0.70, p=0.011). Device-detected RDI ≥37 episodes/h was associated with the occurrence of AF on univariate analysis (HR: 3.88, 95% CI: 2.02–7.44, p<0.001), as well as after correction for either BMI ≥25 kg/m2 (HR: 3.76, 95% CI: 1.94–7.26, p<0.001), or BMI ≥30 kg/m2 (HR: 4.15, 95% CI: 2.15–8.04, p<0.001). Conclusions In heart failure patients, we confirmed the association between ICD-detected SA and AF, an association that persisted independent of patient body habitus. Funding Acknowledgement Type of funding sources: Private grant(s) and/or Sponsorship. Main funding source(s): The study is supported by a research grant from Boston Scientific

Association between implantable defibrillator-detected sleep apnea and atrial fibrillation: The DASAP-HF study.

The Respiratory Disturbance Index (RDI) computed by an implantable cardioverter defibrillator (ICD) algorithm accurately identifies severe sleep apnea (SA). In the present analysis, we tested the hypothesis that RDI could also predict atrial fibrillation (AF) burden. Patients with ejection fraction ≤35% implanted with an ICD were enrolled and followed up for 24 months. One month after implantation, patients underwent a polysomnographic study. The weekly mean RDI value was considered, as calculated during the entire follow-up period and over a 1-week period preceding the sleep study. The endpoints were as follows: daily AF burden of ≥5 min, ≥6 h, ≥23 h. Here, 164 patients had usable RDI values during the entire follow-up period. Severe SA (RDI ≥ 30 episodes/h) was diagnosed in 92 (56%) patients at the time of the sleep study. During follow-up, AF burden ≥ 5 min/day was documented in 70 (43%), ≥6 h/day in 48 (29%), and ≥23 h/day in 33 (20%) patients. Device-detected RDI ≥ 30 episodes/h at the time of the polygraphy, as well as the polygraphy-measured apnea hypopnea index ≥ 30 episodes/h, were not associated with the occurrence of the endpoints, using a Cox regression model. However, using a time-dependent model, continuously measured weekly mean RDI ≥ 30 episodes/h was independently associated with AF burden ≥ 5 min/day (hazard ratio [HR]: 2.13, 95% confidence interval [CI]: 1.24-3.65, p = .006), ≥6 h/day (HR: 2.75, 95% CI: 1.37-5.49, p = .004), and ≥23 h/day (HR: 2.26, 95% CI: 1.05-4.86, p = .037). In heart failure patients, ICD-diagnosed severe SA on follow-up data review identifies patients who are from two- to three-fold more likely to experience an AF episode, according to various thresholds of daily AF burden.

Implantable defibrillator-computed respiratory disturbance index predicts new-onset atrial fibrillation: the DASAP-HF study

Abstract Introduction Sleep apnea (SA), as measured by polysomnography, is a risk factor for atrial fibrillation (AF). The DASAP-HF study previously demonstrated that the Respiratory Disturbance Index (RDI) computed by an implantable cardioverter defibrillator (ICD) algorithm accurately identifies severe SA, is associated with cardiovascular events, and independently predicts death. Purpose In the present analysis we tested the hypothesis that device-detected RDI could also predict AF burden. Methods Patients with left ventricular ejection fraction ≤35% implanted with an ICD were enrolled and followed-up for 24 months. One month after implantation, patients underwent a polysomnographic study. The weekly average RDI value was considered, as calculated by the algorithm during the entire follow-up period and over a 1 week period preceding the sleep study, and patients were stratified according to an RDI value ≥ or <30 episodes/hour. The endpoints were: daily AF burden of ≥5 minutes, ≥6 hours, ≥23 hours. Results 164 enrolled patients had usable RDI values during the entire follow-up period. Severe SA (RDI≥30 episodes/h) was diagnosed in 92 (56%) patients at the time of the polysomnographic study. During a median follow-up of 25 months, AF burden ≥5 minutes/day was documented in 70 (43%), ≥6 hours/day in 48 (29%), and ≥23 hours/day in 33 (20%) patients. Device-detected RDI≥30 episodes/h at the time of the polysomnographic study, as well as the polysomnography-measured apnea hypopnea index ≥30 episodes/h, were not associated with the occurrence of the endpoints, using a Cox regression model. However, using time-dependent Cox model continuously measured weekly average RDI≥30episodes/h was independently associated with AF burden ≥5 minutes/day (HR: 2.13, 95% CI: 1.24–3.65, p=0.006), ≥6 hours/day (HR: 2.75, 95% CI: 1.37–5.49, p=0.004), and ≥23 hours/day (HR: 2.26, 95% CI: 1.05–4.86, p=0.037), after correction for history of AF, left atrial diameter, and gender. Conclusions In heart failure patients implanted with an ICD, device-diagnosed severe SA is associated with a higher risk of AF. In particular, severe SA on follow-up data review identifies patients who are from two- to three-fold more likely to experience an AF episode, according to various thresholds of daily AF burden. Funding Acknowledgement Type of funding sources: Private grant(s) and/or Sponsorship. Main funding source(s): Promoted by the Italian Heart Rhythm Society (AIAC).Supported by a research grant from Boston Scientific.

Efficacy of a Pediatric Sleep Questionnaire for the Diagnosis of Obstructive Sleep Apnea in Children.

Background: Obstructive sleep apnea (OSA) is a source of significant morbidity in children. Polysomnography (PSG), the gold standard diagnostic tool for OSA, is often unavailable due to patient financial and geographic constraints. Our objective is to analyze the relationship between a patient's subjective complaints and the results from their PSG to determine the diagnostic value of the Pediatric Sleep Questionnaire (PSQ) for detecting OSA in children.Methods: A retrospective chart review was conducted for pediatric patients with suspected OSA from March 2012 to January 2014. Preoperative PSQ scores were compared with the results from PSG in the form of Apnea-Hypopnea Index (AHI) and Respiratory Disturbance Index (RDI) values. AHI and RDI values ranging from 1 to 5 were classified as mild OSA while values ranging from 5 to 10 were classified as moderate OSA.Results: A total of 161 patients were recruited for this study with 63 patients (39%) both completing the PSQ and undergoing PSG. Sensitivity of the positive questionnaire was higher in patients with AHI and RDI values indicative of moderate OSA (95% and 100% respectively) versus values indicative of mild OSA (83% and 86% respectively). Conversely, the positive predictive value of the positive questionnaire (n=49) was lower in patients with AHI and RDI values indicative of moderate OSA (39% and 46% respectively) versus values indicative of mild OSA (70% and 80% respectively).Conclusion: The PSQ has high diagnostic value for screening patients with suspected OSA. We recommend the use of the PSQ in the primary care setting for children with suspected OSA.

ICD-detected respiratory disturbance index: accuracy for sleep apnea detection and prognostic value

Abstract Purpose In patients affected by heart failure an association exists between sleep apnea (SA) measured by polysomnography and adverse outcome. Impedance-based implantable cardioverter defibrillator (ICD) algorithms have been designed to compute the Respiratory Disturbance Index (RDI) to identify severe SA. The purpose of the DASAP-HF study was to evaluate the accuracy of RDI for the prediction of severe SA, and investigate the prognostic value of device-detected RDI values. Methods Patients with left ventricular ejection fraction ≤35% implanted with an ICD were enrolled and followed for 24 months. One month after implantation, patients underwent a polysomnographic study (PS) for assessing the apnea-hypopnea index (AHI). The average RDI value was calculated over a 1-week period preceding the sleep study and compared with the assessment of severe SA at PS (AHI ≥30 episodes/h). The endpoint was all-cause death after 24 months. Results 224 out of 265 enrolled patients had usable RDI values. Patients characteristics: 79% male, 67±10 years, BMI 27±7kg/m2, ejection fraction 29±5%, 54% ischemic cardiomyopathy, 50% CRT-D. The mean AHI value at PS was 21±15 episodes/h. The mean RDI value recorded during the week preceding PS was 30±16 episodes/h. RDI values accurately identified severe SA diagnosed at PS (AUC 0.77; 95% CI 0.70–0.83; P=0.001). Based on the ROC curve analysis, RDI ≥29 episodes/h and AHI ≥17 episodes/h maximized sensitivity and specificity for the prediction of death. Both indexes were independently associated with all-cause death but, after correction for the other independent significant prognostic variables, RDI≥29episodes/h yielded stronger prediction (HR: 12.22, 95% CI:1.64–91.37, p=0.015) as compared to AHI ≥17episodes/h (HR: 4.14, 95% CI:1.17–14.66, p=0.028). Moreover, severe SA diagnosed at PS (AHI ≥30episodes/h) was not associated with death (HR: 1.20, 95% CI:0.3817–3.8266, p=0.761). Conclusions In heart failure patients indicated to ICD, severe SA was confirmed to be associated with survival. The ICD-measured RDI accurately identified severe SA detected at PS, and was associated with the risk of death at long-term. Funding Acknowledgement Type of funding source: Private company. Main funding source(s): Boston Scientific

Prognostic value of implantable defibrillator–computed respiratory disturbance index: The DASAP-HF study

Sleep apnea, as measured by polysomnography, is associated with adverse outcomes in heart failure. The DASAP-HF (Diagnosis and Treatment of Sleep Apnea in Patient With Heart Failure) study previously demonstrated that the respiratory disturbance index (RDI) computed by the ApneaScan algorithm (Boston Scientific) accurately identifies severe sleep apnea in implantable cardioverter-defibrillator (ICD) patients. The purpose of the long-term study phase was to assess the incidence of clinical events after 24 months and investigate the association with RDI values. Patients with left ventricular ejection fraction ≤35% implanted with an ICD were enrolled and followed-up for 24 months. The RDI calculated at 1 month after implantation was used to stratify patients (below or above 30 episodes/h). The endpoints were all-cause death and a combination of all-cause death or cardiovascular hospitalization. Of the 265 enrolled patients, 224 had usable RDI values. Severe sleep apnea (RDI ≥30 episodes/h) was diagnosed in 115 patients (51%). These patients were more frequently male (84% vs 72%; P = .030) and had higher creatinine levels. During median follow-up of 25 months, 19 patients (8%) died. Cardiovascular hospitalizations were reported in 19 patients (8%). The risk of all-cause death was higher in patients with RDI ≥30 episodes/h (hazard ratio [HR] 3.33; 95% confidence interval [CI] 1.35-8.21; P = .023), as well as the risk of all-cause death or cardiovascular hospitalization (HR 1.94; 95% CI 1.01-3.76; P = .048). At multivariate analysis, independent predictors of death were RDI ≥30 episodes/h (HR 4.02; 95% CI 1.16-13.97; P = .029) and creatinine levels (HR 2.36; 95% CI 1.26-4.42; P = .008). In heart failure patients implanted with an ICD, higher RDI values are associated with death and cardiovascular hospitalizations. Device-detected severe sleep apnea independently predicts death.

847Interim analysis of the device-detected cardiac tachyarrhythmic events and sleep-disordered breathing (DEDiCATES)" study; focused on baseline characteristics

Abstract Funding Acknowledgements This work is supported by Boston Scientific. Background/introduction: Sleep-disordered breathing (SDB) is one of the common comorbidities in cardiac implantable electronic devices (CIED) patients. It’s feasible to detect SDB using specialized diagnostic function of CIEDs showing comparable performance in diagnostic accuracy of SDB to conventional polysomnography. To date, few studies have investigated the prognostic value of CIED-detected SDB in cardiovascular risk. Purpose In the Device-Detected CArdiac Tachyarrhythmic events and Sleep-disordered breathing (DEDiCATES) study, we aim to determine whether device-detected sleep-disordered breathing (SDB) events are associated with increased risk of cardiac arrhythmias or other cardiovascular (CV) outcomes. Here, we present interim baseline data of the study population to investigate the baseline prevalence and severity of device-detected SDB in CIED patients. Methods The study was designed as a prospective, multicenter, and observational study to include 600 patients. Eligible patients have dual chamber CIEDs with SDB detection function which reports the average number of sleep disturbance events per hour per night in the form of a Respiratory Disturbance Index (RDI). The daily RDI values were collected to measure the severity and burden of SDB. The baseline severity of SDB was determined according to RDI data recorded during the first 1 week, 1 month, and 3 ± 1 months after CIED implantation; patients with RDI≥ 30/h for at least one night are classified into the severe SDB group. Results A total of 313 patients who completed the first device interrogation at 3 ± 1 months were included for analysis. The mean age and CHA2DS2VASc score were 69 and 3.1, respectively. Forty-nine percent of patients were men, and 35.5% were classified as high risk for SDB by Berlin questionnaire. The rate of severe SDB increased with longer monitoring period (83.8% at 1week, 91.6% at 1 month, and 96.4% at 3 ± 1 months). There was no baseline demographic difference between the severe and non-severe SDB groups, except that baseline body mass index (BMI) was higher in the severe group (24.5% vs. 21.5%, p = 0.01). The mean RDI was 36.3, 34.2, and 33.0 per night during the first 1 week, 1 month, and 3 ± 1 months, respectively. Considering the limitation of the categorical criteria of baseline severity, we arbitrarily reclassified the patients according to median mean RDI value. Men were more frequent and BMI was higher in the above-mean RDI group compared to the below-mean RDI group. Using logistic regression analysis, we identified that BMI and male gender were associated with patients with above-mean RDI. Conclusions Conventional categorical classification of SDB severity seems to be limited in its ability to discriminate high risk patients. Thus, more suitable RDI-related variables need to be identified in future outcome analysis. Abstract Figure. Prevalence of baseline severe SDB

STATISTICAL MODELS FOR PREDICTING A PATIENT’S RESPIRATORY DISTURBANCE INDEX

SESSION TITLE: Clinical Prediction and Diagnosis of OSA SESSION TYPE: Original Investigations PRESENTED ON: 10/23/2019 10:45 AM - 11:45 AM PURPOSE: Respiratory disturbance index (RDI) is an important measure to diagnose the severity of obstructive sleep apnea (OSA). To get an accurate RDI value of a patient, an expensive sleep study must be undergone, and the patient needs to wear sleep and breathing monitoring sensors on the skin over a night. Although previous studies developed binary classification models for estimating the presence of OSA by using a patient’s anthropometric information [e.g., neck circumference, body mass index (BMI)], research is limited to directly predict a value of RDI. The present study developed statistical models to predict a patient’s RDI value by incorporating demographic information and anthropometric dimensions. METHODS: RDI data of 620 patients (254 females and 366 males) with a wide range of age and body size was collected at Torr Sleep Center in Corpus Christi, TX in 2007 and 2008. Prediction models for female and male patients were separately developed by employing a stepwise regression method (pin < 0.05 and pout > 0.05) using potential regressors including age, height (H; unit: inch), BMI (B; unit: kg/m2), neck circumference (NC; unit: inch), waist divided by hip circumference (WH), and two-way interactions among other variables (e.g., H × B, H × NC, and B × WH). Note that due to the correlation between waist and hip circumferences, the ratio between waist and hip circumferences was used as a potential regressor in the modeling process. RESULTS: The developed models for predicting RDI value for female and male patients are presented below. RDI female = -65.30 + 0.78 × BMI + 2.90 × NC + 0.29 × Age RDI male = -60.32 + 1.00 × BMI + 3.30 × NC The adj. R2 and root mean squared error (RMSE) of the female and male models are 0.17 and 22.5, and 0.16 and 24.7, respectively. RDI was significantly associated with age (p = 0.014), BMI (p < 0.001), and neck circumference (p = 0.010) for female and BMI (p < 0.001) and neck circumference (p = 0.005) for male. Although age does not have a significant effect on the RDI for the male patients, it was significant for the female patients. CONCLUSIONS: The statistical linear models for predicting a patient’s RDI values have been developed for the first time. The present study is the first study to report a significant effect of age on RDI for a female patient. CLINICAL IMPLICATIONS: The developed model would be particularly useful to predict a patient’s RDI value based on an easily measurable demographic information and anthropometric dimensions. For example, we can anticipate that if a NC of a female patient has been increased by one inch, then RDI value of the patient would be increased by 2.9. Note that the developed models are only applicable to patients, not healthy subjects. DISCLOSURES: No relevant relationships by Jangwoon Park, source=Web Response No relevant relationships by Alaa Sheta, source=Web Response Speaker/Speaker's Bureau relationship with Astra Zaneca, Sunovian, Paratek Please note: $1001 - $5000 Added 01/13/2019 by Salim Surani, source=Web Response, value=Consulting fee

Variability of Sleep Apnea Severity and Risk of Atrial Fibrillation: The VARIOSA-AF Study.

This study sought to determine night-to-night variability in the severity of sleep-disordered breathing (SDB) and the dynamic intraindividual relationship to daily risk of incident atrial fibrillation (AF) by using simultaneous long-term day-by-day SDB and AF monitoring. Night-to-night variability in SDB severity may result in a dynamic exposure to SDB related conditions impacting the timing and extent of cardiovascular responses. This study was an observational cohort study. Daily data for AF burden and average respiratory disturbance index (RDI) were extracted from pacemakers capable of monitoring nightly SDB and daily AF burden in 72 patients. Nightly RDI values were grouped into quartiles of severity within each patient. AF burdens of >5 min, >1 h, and >12 h were the outcome variables. A total of 32% of patients had a mean RDI of≥20/h, indicative of overall severe SDB. There was significant night-to-night variation in RDI reflected by an absolute SD of ±6.3 events/h (range 2 to 14 events/h) within any givenpatient. Within each patient, the nights with the highest RDI (in their highest quartile) conferred a 1.7-fold (1.2to2.2; p<0.001), 2.3-fold (1.6 to 3.5; p< 0.001), and 10.2-fold (3.5 to 29.9; p< 0.001) increase risk of having atleast 5 min, 1h, and 12 h, respectively, of AF during the same day compared with the best sleep nights (in their lowestquartiles). There is considerable night-to-night variability in SDB severity which cannot be detected by 1 single overnight sleep study. SDB burden may be a better metric with which to assess the extent of dynamic SDB related cardiovascular responses such as daily AF risk than the categorical diagnosis of SDB. (Night-to-Night Variability in Severity of Sleep Apnea and Daily Dynamic Atrial Fibrillation Risk [VARIOSA-AF]; ACTRN 12618000757213).

Relationship between sleep-disordered breathing and central systolic blood pressure in a community-based population: the Toon Health Study.

Sleep-disordered breathing (SDB) is linked with brachial blood pressure. Although central systolic blood pressure (cSBP) is a better predictor of cardiovascular diseases than is brachial blood pressure, the association between SDB and cSBP is not fully understood. This cross-sectional study included 1484 participants without cardiovascular diseases who were enrolled in the Toon Health Study between 2009 and 2012. The respiratory disturbance index (RDI) was estimated with a one-night sleep test using an airflow monitor. Participants were grouped into three categories according to RDI level: mild (<10 events/h), moderate (10 to <20 events/h), and severe (≥20 events/h). The cSBP was measured using a noninvasive automated tonometer. Multivariable-adjusted cSBP means for the mild, moderate, and severe RDI categories were, respectively, 116.0, 118.0, and 120.7 mm Hg (p for trend = 0.02) for men and 111.8, 113.7, and 111.7 mm Hg (p for trend = 0.59) for women. The association for men was no longer significant after adjusting for BMI. When stratified by BMI (<22 or ≥22 kg/m2), the RDI was associated with cSBP among men with BMI ≥ 22 kg/m2, and this association was of borderline significance. Augmentation index, pulse pressure amplification, and brachial blood pressure were not significantly associated with the RDI. Higher RDI values were associated with increased multivariable-adjusted cSBP means among men. This association was more evident among those with BMI ≥ 22 kg/m2. In conclusion, we found that the RDI was associated with cSBP among men, and this association was independent of confounding variables among individuals above the ideal weight.

Rationale, design, and endpoints of the ‘DEvice-Detected CArdiac Tachyarrhythmic Events and Sleep-disordered Breathing (DEDiCATES)’ study: Prospective multicenter observational study of device-detected tachyarrhythmia and sleep-disordered breathing

BackgroundFew studies have investigated the prognostic value of cardiac implantable electronic device (CIED)-detection of sleep-disordered breathing (SDB) for risk stratification of cardiovascular events. In the Device-Detected CArdiac Tachyarrhythmic events and Sleep-disordered breathing (DEDiCATES) study, we aim to determine whether device-detected SDB events are associated with increased risk of cardiac arrhythmias or other cardiovascular outcomes. Methods and designSix-hundred patients (300 patients with low-voltage pacing devices and 300 with high-voltage defibrillator devices) who have dual chamber CIEDs with AP Scan™ function (Boston Scientific Inc., Marlborough, MA, USA) are planned to be enrolled in this study. AP Scan reports the average number of sleep disturbance events per hour per night in the form of a Respiratory Disturbance Index (RDI). The daily RDI values are to be used for quantitative measurement of the severity and burden of SDB. CIED-detected atrial high rate episodes (AHREs) and clinical atrial tachyarrhythmia will be assessed as the primary outcomes over a follow-up period of 2 years. Correlations between CIED-detected SDB and AHRE burdens will be analyzed. The secondary outcomes are CIED-detected or clinical ventricular arrhythmic events, stroke, heart failure hospitalization, mortality, and quality of life. ConclusionThis study will determine the prognostic value of automated diagnostic function of CIED for SDB, which will help to improve the cardiovascular prognoses of CIED patients by enabling convenient and accurate assessments of SDB events.

Association between obesity and sleep disorders in postmenopausal women

To investigate the relationship between obesity and sleep architecture in postmenopausal women. One hundred seven postmenopausal women from the Ambulatory of Integrative Treatment for Female Sleep Disorders were invited by telephone to participate in this study. Fifty-three completed the study. We included women aged 50 to 70 years, and excluded women on hormone therapy or missing data. The study consisted of two meetings, including a full-night polysomnography. Menopause status was confirmed by amenorrhea for at least 1 year. Anthropometric measurements included: body mass, height, body mass index (BMI), waist circumference, hip circumference, waist-to-hip ratio (WHR), and neck circumference. Participants were allocated into two groups according to BMI: nonobese group (BMI <30 kg/m) and obese group (BMI ≥30 kg/m). The obese group had significantly (P < 0.01) increased values of BMI, neck circumference, waist circumference, and hip circumference. WHR was similar between the groups (P = 0.77). Obese participants had significantly increased values of respiratory disturbance index (16.4 vs 9.3 n°/h) and apnea-hypopnea index (14.2 vs 5.6 n°/h). Rapid eye movement sleep latency was positively correlated to body mass (r = P < 0.01), BMI (P < 0.01), and hip circumference (P = 0.01). WHR was negatively correlated to sleep efficiency (P = 0.03). The linear regression model showed that BMI (P < 0.01) and WHR (P < 0.01) were positive predictors of rapid eye movement sleep latency. In postmenopausal women, high BMI and abdominal obesity are sources of sleep disturbances, decreasing deep sleep, and sleep efficiency, while increasing the risk of obstructive sleep apnea.

Implantable cardioverter-defibrillator–computed respiratory disturbance index accurately identifies severe sleep apnea: The DASAP-HF study

Sleep apnea (SA) is a relevant issue in the management of patients with heart failure for risk stratification and for implementing treatment strategies. The purpose of this study was to evaluate in patients with implantable cardioverter-defibrillators (ICDs) the performance of the respiratory disturbance index (RDI) computed by the ApneaScan algorithm (Boston Scientific Inc., Natick, MA) as a discriminator of severe SA. ICD-indicated patients with left ventricular ejection fraction ≤35% were enrolled. One month after implantation, patients underwent a polysomnographic study. We evaluated the accuracy of the RDI for the prediction of severe SA (apnea-hypopnea index [AHI] ≥30 episodes/h) and the agreement between RDI and AHI during the sleep study night. Two hundred sixty-five patients were enrolled to obtain the required sample of 173 patients with AHI and RDI data for analysis. The mean AHI was 21 ± 15 episodes/h and severe SA was diagnosed in 38 patients (22%), while the mean RDI was 33 ± 13 episodes/h. On the basis of the receiver operating characteristic curve analysis of RDI values, the area under the curve was 0.77 (95% confidence interval [CI] 0.70-0.83; P < .001). At an RDI value of 31 episodes/h, severe SA was detected with 87% (95% CI 72%-96%) sensitivity and 56% (95% CI 48%-66%) specificity. RDI closely correlated with AHI recorded during the same night (r=0.74; 95% CI 0.57-0.84; P < .001), and the Bland-Altman agreement analysis revealed a bias of 11 episodes/h, with limits of agreement being -10 to 32 episodes/h. The RDI accurately identified severe SA and demonstrated good agreement with AHI. Therefore, it may serve as an efficient tool for screening patients at risk of SA.

Causes of Excessive Daytime Sleepiness in Patients with Acute Stroke—A Polysomnographic Study

Sleep disorders are common in stroke patients. Sleep-disordered breathing (SDB), which is present in up to 72% of stroke patients, is the most frequent cause of excessive daytime sleepiness (EDS) in common population. The aim of this study was to assess the frequency of EDS in stroke patients and to analyze the impact of SDB, stroke severity, and location of stroke on EDS in the acute phase of stroke. We enrolled 102 patients with the clinical diagnosis of acute stroke. Baseline clinical characteristics were recorded on admission. An Epworth sleepiness scale score higher than 9 was considered as EDS. To detect SDB, we performed standard overnight polysomnography within 4 ± 2 days after the stroke onset. EDS was present in 21 patients (20.6%). In a population with EDS, we found a significantly higher number of obstructive apneic pauses, central apneic pauses, as well as significantly higher values of respiratory disturbance index (RDI), RDI during nonrapid eye movement sleep, desaturation index, and significant decrease of REM sleep duration. RDI (odds ratio [OR], 1.031; 95% confidence interval [CI], 1.007-1.056; P = .01) and duration of REM sleep (OR, .922; 95% CI, .853-.997; P = .042) were the only independent variables significantly associated with EDS in a binary multivariate regression model. SDB is a common, significant, and treatable cause of EDS in acute stroke patients. We suppose that examination in sleep laboratories is reasonable in all stroke patients with EDS, although the impact of SDB therapy on EDS and overall outcome in acute stroke remains unknown.

Assessment of respiratory disturbance index determined with a non-restrictive monitor and of autonomic nervous system parameters in heart failure patients: A pilot study

BackgroundThere is a link between sympathetic overactivity and sleep-disordered breathing (SDB), and both of which are important indicators of the development of heart failure. To manage the increasing numbers of heart failure patients, any method used to check for them needs to be as non-invasive, simple, and cost-effective as possible. The purpose of this study is to assess screening of SDB with a non-restrictive monitor and the autonomic nervous system in heart failure patients. MethodsThe subjects were 49 patients (mean age: 67 years; male: 78%) hospitalized for worsening heart failure. After stabilization with appropriate medical therapy, each patient simultaneously underwent sleep apnea syndrome (SAS) screening with the SD-101 (Kenzmedico Co. Ltd., Saitama, Japan), which is a novel, non-restrictive, sheet-like monitor for SAS screening, and assessment of heart rate variability (HRV) with a Holter monitor. In addition, we assessed daytime sleepiness by using the Epworth Sleepiness Scale. ResultsThe mean respiratory disturbance index (RDI) was 21.9events/h. Males had significantly greater RDI values than females (24.5±11.2events/h vs. 13.0±6.2events/h, p<0.001). RDI on SD-101 testing was closely correlated with cyclic variation of heart rate index obtained with a Holter electrocardiogram scanner (r=0.843). Although plasma brain natriuretic peptide level was not correlated with HRV, plasma norepinephrine level was moderately well correlated with the total low- to high-frequency ratio of HRV (r=0.529). ConclusionsSAS screening is important for heart failure patients, because absence of subjective sleepiness is not reliable in ruling out SDB. The SAS screening with SD-101 might apply for managing heart failure.

WatchPAT versus Polysomnography: A Meta‐analysis

Objectives:Recognize the correlation between WatchPAT and Polysomnography (PSG) results including the apnea‐hypopnea index (AHI), respiratory disturbance index (RDI), and oxygen desaturation index (ODI).Methods:A systematic literature review was performed by searching Pubmed, OVID Medline, and the Cochrane database for articles from June 2000 comparing WatchPAT to PSG. Meta‐analysis of continuous measures using the fixed effect model was performed.Results:Twelve studies that directly compared the results of AHI, RDI, and ODI between WatchPAT and PSG were identified. Five of the 12 studies, involving a total of 476 patients, measured AHI. WatchPAT AHI was not found to be significantly different from PSG AHI (standardized mean difference [SMD], 0.10; 95% confidence interval [CI], –0.08 to 0.28). RDI values, obtained from 5 studies with a total of 612 patients, did not significantly differ between WatchPAT and PSG (SMD, 0.08; 95% CI, –0.07 to 0.24). No significant difference was found between WatchPAT ODI and PSG ODI values from 2 studies with a total of 298 patients (SMD, 0.11; 95% CI, –0.12 to 0.34).Conclusions:The respiratory indices provided by WatchPAT are comparable to those obtained by PSG. This meta‐analysis reinforces the validation of WatchPAT as an alternative to PSG in the diagnosis of obstructive sleep apnea (OSA). With WatchPAT, patients can be evaluated in their own habitual environment rather than in a sleep lab. Therefore, the use of WatchPAT provides a less stress‐inducing option for patients and a more financially efficient method for the evaluation of OSA.

Clinical effect of surgical correction for nasal pathology on the treatment of obstructive sleep apnea syndrome.

ObjectivesThis study aimed to evaluate the hypothesis that relief of nasal obstruction in subjects with obstructive sleep apnea (OSA) would lead to reduce OSA severity and to discuss the available evidence on the clinical efficacy of nasal surgery as a treatment modality for OSA.Study DesignTwenty-five subjects who had reduced patency of nasal cavity and narrowing of retroglossal or retropalatal airways were diagnosed with OSA and underwent nasal surgery, such as septoplasty or turbinoplasty to correct nasal pathologies. The effect of the surgery on nasal patency was quantified by measuring minimal cross-sectional area (MCA) using acoustic rhinometry. The watch-PAT-derived respiratory disturbance index (RDI), apnea and hypopnea index (AHI), lowest oxygen saturation, and valid sleep time were measured before and after nasal surgery.ResultsThe present study shows that the AHI and RDI decreased significantly and the lowest oxygen saturation and valid sleep time rose after nasal surgery in 25 OSA subjects. In addition, a reduction in subjective symptoms was observed in subjects and mean MCA increased after nasal surgery. Fourteen subjects were classified as responders and 11 subjects as non-responders. Responders showed considerable improvement of their subjective symptoms and the AHI and RDI were significantly lower after surgery. We found that the changes between pre- and post-operative AHI and RDI values were minimal in 11 non-responders. However, daytime somnolence and REM sleep time improved after nasal surgery in non-responders.ConclusionsOur study provides evidence that the surgical treatment of nasal pathology improves nasal airway patency and reduces OSA severity in 56% subjects. Furthermore, correction of nasal pathology appears to result in improved sleep quality in both responder and non-responders OSA subjects.

The morphology of the nasopharyngeal inlet in obstructive sleep apnea

Routine flexible optic laryngoscopy (FOL) can visualize the airway from the nasopharynx to the hypopharynx in obstructive sleep apnea (OSA). With the tip of a flexible endoscope at the nasopharyngeal inlet (NPI), we can visualize the morphology of this area. We evaluated the effect of NPI morphology on OSA severity. Videos were obtained during FOL examinations of the NPI in 83 patients (11 females, 72 males; mean age 42.1 ± 9.5 years) and NPI morphology was examined. Two main morphologies were seen: wide and narrow. The narrow NPI group (n = 45) was further subdivided into kidney-shaped (n = 34), elliptical (n = 6), and circumferential (n = 5) groups. The wide NPI group (n = 38) was subdivided into circumferential (n = 20) and kidney-shaped (n = 18) groups. Mean Respiratory Disturbance Index (RDI) values were 30.38 ± 22.36 and 14.51 ± 13.9 in the narrow and wide groups, respectively. Mean RDI values were 45.32 ± 30.6, 23.74 ± 10.8, and 28.72 ± 21.5 in the narrow circumferential, elliptical, and kidney-shaped groups, respectively. Mean RDI values were 11.58 ± 12.91 and 17.8 ± 14.6 in the wide circumferential and kidney-shaped groups, respectively. RDI values were significantly lower in the wide morphology group (p < 0.0005). NPI morphology might predict OSA during routine FOL examination. Further analysis of the subgroups supported evidence of narrowing, reflected as higher RDI values.

Atrial fibrillation is associated with severe sleep‐disordered breathing in patients with ischaemic stroke and transient ischaemic attack

Sleep-disordered breathing (SDB) is a risk factor for cerebrovascular disease. We investigated the frequency of SDB in Japanese patients with acute ischaemic stroke and transient ischaemic attack (TIA), as well as factors associated with SDB severity. Between April 2010 and March 2011, we prospectively enrolled patients with ischaemic stroke and TIA within 24 h of onset to participate in a sleep study within 7 days of admission. We defined SDB as a respiratory disturbance index (RDI) (number of apnoeas or hypopnoeas per hour) of ≥ 5. Patients were assigned to groups based on RDI values of ≥ 30 (severe) and <30 (absent or not severe). The frequency of SDB and factors associated with severity were investigated using multivariate regression analysis. We enrolled 150 patients amongst whom 126 (84%) had SDB. The frequencies of SDB were 21 (75%) patients with TIA, 105 (86%) with ischaemic stroke, 8/10 (80%) with large artery atherosclerosis, 14/14 (100%) with small vessel occlusion, 37/41 (90%) with cardioembolism and 46/57 (81%) with other causes of stroke/undetermined. Severe SDB was evident in 44 (29%) patients. The frequency of males (75% vs. 56%, P = 0.027), atrial fibrillation (AF) (39% vs. 23%, P = 0.045), higher body mass index (23.8 ± 3.8 vs. 22.3 ± 3.8, P = 0.043) and a larger neck circumference (37.8 ± 4.3 vs. 35.8 ± 4.2, P = 0.012) was significantly higher in the group with severe SDB. Multivariate regression analysis found that AF (OR 2.4; 95% CI 1.079-5.836, P = 0.0359) was independently associated with severe SDB. Most Japanese patients with acute ischaemic stroke and TIA had SDB, and AF was associated with SDB.

Palatoplasty as the Technique of Choice for Prevention of Obstructive Sleep Apnea Secondary to Surgery for Velopharyngeal Insufficiency

The aim of this study is to compare patients treated with pharyngoplasty and those treated with palatoplasty for velopharyngeal insufficiency to establish what surgical procedure poses the highest risk for developing sleep apnea. The hypothesis tested in this study is that the incidence of obstructive sleep apnea syndrome associated with pharyngoplasty is greater than that associated with palatoplasty for velopharyngeal insufficiency. Twenty patients were taken from the Institution FISULAB. Observational cohort analytic study. An overnight polysomnographic study was used to determine the incidence and severity of obstructive sleep apnea syndrome. The incidence of obstructive sleep apnea syndrome following pharyngoplasty was shown to be significantly higher than after palatoplasty. The apnea-hypopnea index, also called the respiratory disturbance index, was 12.7 in the pharyngoplasty group and 1.35 in the palatoplasty group (p < .001). When obstructive sleep apnea syndrome was stratified into different levels of severity according to the values of respiratory disturbance index, there were noticeable differences between these two groups. In the palatoplasty group, one patient had mild obstructive sleep apnea syndrome. In the pharyngoplasty group, two patients had mild obstructive sleep apnea syndrome, one patient had moderate obstructive sleep apnea syndrome, and two patients had severe obstructive sleep apnea syndrome. When comparing the apnea-hypopnea index (i.e., respiratory disturbance index) of patients treated for velopharyngeal insufficiency with palatoplasty versus pharyngoplasty, we observed an important difference between the groups, with the highest indices in the pharyngoplasty group.