Central Apnea Index Research Articles

The maturation changes of sleep-related respiratory abnormalities in infants with laryngomalacia.

Obstructive sleep apnea (OSA) and central sleep apnea (CSA) are common in infants with laryngomalacia. The purpose of this study was to evaluate developmental changes in sleep-related breathing disorders over time in infants with laryngomalacia and understand the effect of supraglottoplasty (SGP) and nonsurgical treatment. This is a retrospective review of infants with laryngomalacia who had at least 2 diagnostic polysomnography studies performed from January 2000 and May 2015. We included infants who had either OSA or CSA. Comparison of sleep and respiratory parameters by age group (0-6, 6-12, and >12 months old) was performed in both SGP and non-SGP groups using a mixed-effect regression model. A log-normal mixed model was used to explore the changes in sleep and respiratory parameters with age. The time to resolution of CSA and OSA was analyzed using nonparametric survival analysis. A total of 102 infants were included; 57 had only OSA and 45 had both CSA and OSA. There were significant decreases in apnea-hypopnea index, obstructive index, central apnea index, and arousal index with increasing age in both SGP and non-SGP groups. The mean age at resolution of CSA (central apnea index < 5) was 7.60 months old for SGP and 12.57 months old for non-SGP (P < .05). There were no significant differences in the mean age at resolution of OSA (obstructive index < 1; 35.18 [SGP] vs 41.55 months [non-SGP]; P = .60) between SGP and non-SGP groups. Infants with neurologic disease, congenital anomalies, or genetic syndromes required significantly more time to resolve OSA (28.12 [normal] vs 53.13 [neurological] vs 59.53 months [congenital anomalies and genetic]; P < .01). Both OSA and CSA improve in infants with laryngomalacia with increasing age regardless of SGP. The mechanism underlying these changes may involve airway growth and maturation of respiratory control. Time to resolution of OSA is affected by the presence of neurologic diseases, congenital anomalies, and genetic syndromes. Further studies are needed to confirm these findings and to evaluate long-term outcomes in this population.

Algorithm for automatic detection of self-similarity and prediction of residual central respiratory events during continuous positive airway pressure.

Study ObjectivesSleep-disordered breathing is a significant risk factor for cardiometabolic and neurodegenerative diseases. High loop gain (HLG) is a driving mechanism of central sleep apnea or periodic breathing. This study presents a computational approach that identifies “expressed/manifest” HLG via a cyclical self-similarity feature in effort-based respiration signals.MethodsWorking under the assumption that HLG increases the risk of residual central respiratory events during continuous positive airway pressure (CPAP), the full night similarity, computed during diagnostic non-CPAP polysomnography (PSG), was used to predict residual central events during CPAP (REC), which we defined as central apnea index (CAI) higher than 10. Central apnea labels are obtained both from manual scoring by sleep technologists and from an automated algorithm developed for this study. The Massachusetts General Hospital sleep database was used, including 2466 PSG pairs of diagnostic and CPAP titration PSG recordings.ResultsDiagnostic CAI based on technologist labels predicted REC with an area under the curve (AUC) of 0.82 ± 0.03. Based on automatically generated labels, the combination of full night similarity and automatically generated CAI resulted in an AUC of 0.85 ± 0.02. A subanalysis was performed on a population with technologist-labeled diagnostic CAI higher than 5. Full night similarity predicted REC with an AUC of 0.57 ± 0.07 for manual and 0.65 ± 0.06 for automated labels.ConclusionsThe proposed self-similarity feature, as a surrogate estimate of expressed respiratory HLG and computed from easily accessible effort signals, can detect periodic breathing regardless of admixed obstructive features such as flow limitation and can aid the prediction of REC.

Treatment of Cheyne-Stokes respiration with adaptive servoventilation-analysis of patients with regard to therapy restriction.

PurposeThe SERVE-HF study revealed no benefit of adaptive servoventilation (ASV) versus guideline-based medical treatment in patients with symptomatic heart failure, an ejection fraction (EF) ≤45% and a predominance of central events (apnoea-hypopnea Index [AHI] > 15/h). Because both all-cause and cardiovascular mortality were higher in the ASV group, an EF ≤ 45% in combination with AHI 15/h, central apnoea-hyponoea index [CAHI/AHI] > 50% and central apnoea index [CAI] > 10/h were subsequently listed as contraindications for ASV. The intention of our study was to analyse the clinical relevance of this limitation.MethodsData were analysed retrospectively for patients treated with ASV who received follow-up echocardiography to identify contraindications for ASV.ResultsEchocardiography was conducted in 23 patients. The echocardiogram was normal in 10 cases, a left ventricular hypertrophy with normal EF was found in 8 patients, there was an EF 45–50% in 2 cases and a valvular aortic stenosis (grade II) with normal EF was found in 1 case. EF <45% was present in just 2 cases, and only 1 of these patients also had more than 50% central events in the diagnostic night.ConclusionThe population typically treated with ASV is entirely different from the study population in SERVE-HF, as nearly half of the patients treated with ASV showed a normal echocardiogram. Thus, the modified indication for ASV has little impact on the majority of treated patients. The current pathomechanistic hypothesis of central apnoea must be reviewed.

EFFECTS OF TRANSVENOUS PHRENIC NERVE STIMULATION ON CENTRAL SLEEP APNEA AND SLEEP ARCHITECTURE: THE 5 YEAR ANALYSIS

EFFECTS OF TRANSVENOUS PHRENIC NERVE STIMULATION ON CENTRAL SLEEP APNEA AND SLEEP ARCHITECTURE: THE 5 YEAR ANALYSIS

Cardiorespiratory Monitoring Data during Sleep in Healthy Canadian Infants

Rationale: Sleep study interpretation in children needs to be based on age-specific normal values. Although several studies have reported normal cardiorespiratory parameters during sleep in children and adolescents, few have included younger children.Objectives: To describe cardiopulmonary indices, specifically oxygen saturation and heart rate, as well as frequency of obstructive and central apneas in healthy 1-year-old Canadian infants during sleep.Methods: Home sleep cardiorespiratory monitoring was performed among infants participating in the Edmonton subcohort of the CHILD (Canadian Healthy Infant Longitudinal Development) study at their 1-year follow-up visit. A portable sleep monitoring device, which included a nasal pressure cannula, an oronasal thermal airflow sensor, a pulse oximeter, and respiratory inductance plethysmography belts, was used to collect sleep architecture and cardiorespiratory data during one night of monitoring in the home. Sleep scoring was done in blocks of 5 minutes using a novel pilot sleep scoring algorithm.Results: Among the 562 subjects (mean ± standard deviation age 1.1 ± 0.2 yr) who attempted home sleep cardiorespiratory monitoring, 91% provided technically acceptable data with no loss of signal preventing analysis of any parameter. Obstructive and central apneas were rare, with a median obstructive apnea index of 0.0 events/h (10th percentile, 0.0; 90th percentile, 0.5) and a median central apnea index of 2.5 events/h (10th percentile, 0.6; 90th percentile, 7.1). Median oxygen saturation was 97.0% (10th percentile, 95.4; 90th percentile, 97.9). The oxygen desaturation index was 6.7 events/h (10th percentile, 1.4; 90th percentile, 15.8), with infants spending only 0.1% (10th percentile, 0.0; 90th percentile, 0.6) of the time with an oxygen saturation below 92%.Conclusions: These results provide important reference data for healthy infants undergoing cardiorespiratory monitoring during sleep.

Transvenous Phrenic Nerve Stimulation is Safe and Effective in Patients with Heart Failure and Cheyne-stokes Respiration

Introduction The most common type of central sleep apnea (CSA) breathing pattern in patients with heart failure (HF) is Cheyne-Stokes respiration (CSR). CSR manifests as a cyclical pattern of apnea and hyperventilation, with absence of airflow and respiratory effort followed by hyperventilation in a crescendo-decrescendo pattern. CSR may be a predictor of negative clinical outcomes in HF patients. Purpose Examine the response to transvenous phrenic nerve stimulation (TPNS) in patients with HF and different amounts of CSR. Methods Patients with CSA and HF who participated in the remedē System Pivotal Trial were divided into clinically relevant subgroups based on percentage of sleep in CSR (%CSR: 50%) during their baseline polysomnogram. The subgroups were analyzed for efficacy and safety by randomized group (TPNS vs control [no TPNS]). Epworth sleepiness scale (ESS) was also collected. Results At baseline, higher percentage CSR subgroups had lower left ventricular ejection fraction (median 45% for CSR 50%). Baseline apnea-hypopnea index (AHI) indicated severe CSA in all subgroups. All CSR subgroups receiving TPNS therapy had more than 50% of patients achieve ≥50% reduction in AHI at 6 months (see Table); control response rates were ≤11% in each CSR subgroup. The AHI decreased by ≥21 events/hour in each CSR subgroup on therapy while Control subgroups had little or no improvement. The central apnea index decreased to median ≤3 events/hour in each TPNS CSR subgroup; each control subgroup had median 22-24 events/hour remaining at 6 months. Baseline daytime sleepiness was worse in lower %CSR subgroups, however improved in all subgroups. No apparent relationship existed between %CSR and cardiovascular death in patients using TPNS therapy through 6 months, with the only death being in the 20-50% CSR subgroup; the death was determined not related to device, therapy or procedure by the clinical events committee. Further, 2/22 control subjects with CSR>50% experienced a cardiovascular death compared to 0/12 in the TPNS treated subgroup. Conclusions Transvenous phrenic nerve stimulation can treat CSA in HF patients regardless of the percentage of sleep in CSR and no signal of increased mortality was observed.

Central Sleep Apnea and Pacing-Induced Cardiomyopathy

The role of central sleep apnea (CSA) in pacing-induced cardiomyopathy (PICM) remains speculative. In a prospective trial entitled UPGRADE, the presence of CSA was assessed by single-night polysomnography (PSG) in 54 PICM patients within 1 month after left ventricular lead implantation (with biventricular stimulation still not activated). CSA was diagnosed in half of patients (n = 27). Patients with moderate or severe CSA were randomized to cardiac resynchronization therapy (CRT) versus right ventricular pacing (RVP) in a double-blinded cross-over design and re-scheduled for a follow-up PSG within 3 to 5 months. After crossing-over of stimulation mode another PSG was conducted 3 to 5 months later. CRT led to a significant increase in left ventricular ejection fraction and significant reduction in left ventricular end systolic volumes and N-terminal pro brain natriuretic peptide plasma levels, whereas no significant effects were observed with ongoing RVP. CSA was significantly improved after 3.9 (3.2 to 4.4) months of CRT: apnea-hypopnea index decreased from 39.1 (32.1 to 54.0) events per hour at baseline to 22.2/h (10.9 to 36.7) by CRT (p <0.001). Central apnea index decreased from 27.1/h (17.7 to 36.1) at baseline to 6.8/h (1.1 to 14.4) after CRT activation (p <0.001). Ongoing RVP yielded only a minor improvement in apnea-hypopnea index and central apnea index. Pre-existent CSA did not affect structural response rate and had no impact on mid-term follow-up (median 2.8 years). In conclusion, CSA is highly prevalent in patients with PICM. CRT upgrading significantly improves CSA leading to a similar outcome in PICM patients without pre-existent CSA.

The influence of opioids and nonopioid central nervous system active medications on central sleep apnea: a case-control study.

Opioids are known to contribute to central sleep apnea (CSA), but the influence of nonopioid central nervous system active medications (CNSAMs) on CSA remains unclear. In light of the hypothesized impact of nonopioid CNSAMs on respiration, we examined the relationships between the use of opioids only, nonopioid CNSAMs alone, and their combination with CSA. Among all adults who underwent polysomnography testing at the University of Michigan's sleep laboratory between 2013 and 2018 (n = 10,606), we identified 212 CSA cases and randomly selected 300 controls. Participants were classified into four groups based on their medication use: opioids alone, nonopioid CNSAMs only, their combination, and a reference group, including those who did not use any of these medications. We defined CSA as a binary outcome and as a continuous variable using central apnea index data. Logistic and linear regression were used to examine associations between medication use, CSA diagnosis, and central apnea index. Study participants included 58% men, and mean age was 50 (± 14 standard deviation years. Nearly half of the study participants did not use opioids or nonopioid CNSAMs, 6% used opioids alone, 27% nonopioid CNSAMs alone, and 16% used a combination of these medications. In adjusted analyses, opioids-only users had a nearly twofold increase in CSA odds, whereas those who used a combination of opioids and nonopioid CNSAMs had fivefold higher odds of CSA relative to the reference group. In contrast, the use of nonopioid CNSAMs alone had protective associations with CSA. This report showed increased odds of CSA, particularly among patients with sleep complaints who were prescribed opioids in combination with nonopioid CNSAMs compared with those who did not use any of these medications.

Stridor during sleep: description of 81 consecutive cases diagnosed in a tertiary sleep disorders center.

To describe the characteristics of stridor during sleep (SDS) in a series of adults identified by video-polysomnography (V-PSG). Retrospective clinical, V-PSG, laryngoscopic, and therapeutic data of patients diagnosed with SDS in a tertiary referral sleep disorders center between 1997 and 2017. A total of 81 patients were identified (56.8% males, age 61.8 ± 11.2 years). Related etiologies were multiple system atrophy (MSA), amyotrophic lateral sclerosis, spinocerebellar ataxia type 1, anti-IgLON5 disease, fatal familial insomnia, brainstem structural lesions, vagus nerve stimulation, recurrent laryngeal nerve injury, the effect of radiotherapy on the vocal cords, cervical osteophytes, and others. Stridor during wakefulness coexisted in 13 (16%) patients and in MSA was only seen in the parkinsonian form. Laryngoscopy during wakefulness in 72 (88.9%) subjects documented vocal cord abductor impairment in 65 (90.3%) and extrinsic lesions narrowing the glottis in 2 (2.4%). The mean apnea-hypopnea index (AHI) was 21.4 ± 18.6 and CT90 was 11.5 ± 19.1. Obstructive AHI > 10 occurred in 52 (64.2%) patients and central apnea index >10 in 2 (2.4%). CPAP abolished SDS, obstructive apneic events and oxyhemoglobin desaturations in 58 of 60 (96.7%) titrated patients with optimal pressure of 9.0 ± 2.3 cm H20. Tracheostomy in 19 (23.4%) and cordotomy in 3 (3.7%) subjects also eliminated SDS. SDS in adults is linked to conditions that damage the brainstem, recurrent laryngeal nerve, and vocal cords. V-PSG frequently detects obstructive sleep apnea and laryngoscopy usually shows vocal cord abductor dysfunction. CPAP, tracheostomy, and laryngeal surgery abolish SDS.

Transvenous phrenic nerve stimulation to treat idiopathic central sleep apnea.

Idiopathic central sleep apnea (ICSA) is a rare disorder diagnosed when known causes of central sleep apnea are excluded. No established treatments exist for ICSA, and long-term studies are lacking. We assessed the long-term effectiveness and safety of transvenous phrenic nerve stimulation in patients with ICSA. In the remedē System Pivotal Trial, 16/151 (11%) participants with central sleep apnea were diagnosed as having ICSA. Patients were implanted and followed through 18 months of active therapy. Polysomnograms obtained at baseline and at 6, 12, and 18 months were scored by a central laboratory. Sleep metrics and patient-reported quality of life outcomes were assessed. Patients experienced moderate-severe central sleep apnea. The baseline AHI, central apnea index, and arousal index were 40, 25, and 32 events/h of sleep, respectively. These metrics improved at 6, 12, and 18 months of therapy: the AHI decreased by 25, 25, and 23 events/h (P < .001 at each visit), the central apnea index by 22, 23, and 22 events/h (P < .001 at each visit), and the arousal index by 12 (P = .005), 11 (P = .035), and 13 events/h (P < .001). Quality of life instruments showed clinically meaningful improvements in daytime somnolence, fatigue, general and mental health, and social functioning. The only related serious adverse event was lead component failure in 1 patient. This is the longest prospective study for the treatment of ICSA. Transvenous phrenic nerve stimulation significantly decreased sleep-disordered breathing metrics with consequent improvement in quality of life at 6 months, and all benefits were sustained through 18 months. Registry: ClinicalTrials.gov; Name: Respicardia, Inc. Pivotal Trial of the remedē System; URL: https://clinicaltrials.gov/ct2/show/NCT01816776; Identifier: NCT01816776.

Polysomnographic characteristics and sleep-disordered breathing in Schaaf-Yang syndrome.

Schaaf-Yang syndrome (SYS) is a genetic disorder caused by truncating variants in the MAGEL2 gene located in the maternally imprinted Prader-Willi syndrome (PWS) region at 15q11-13. The SYS phenotype shares features with PWS, a syndrome with known high incidence of sleep disorders. However, the spectrum of sleep-disorders in SYS has not been described. We performed a retrospective analysis of polysomnograms from 22 patients in an international SYS cohort. Sleep characteristics for individuals with the common c.1996dupC variant (n = 10) were compared to other truncating variants (n = 11). We collected 33 sleep study reports from 22 patients, ages 2 months - 18.5 years (mean 6.5 years). Mean sleep efficiency was 70.5% (range 45%-93%) with arousal index 14.1/h(1.2-45/h). The mean apnea-hypopnea index (AHI) was 19.1/h (0.9-49/h) with mean obstructive AHI (oAHI) of 16.3/h(0.6-49/h). Mean central apnea index was 2.8/h(0-14/h). Mean oxygen desaturation index was 20.8/h(range 0-85/hr). Obstructive sleep apnea (OSA) was diagnosed in 81%, and 62% had moderate or severe OSA. Elevated central apnea index occurred in 9.5%. Comparison by genotype groups and age did not reveal any difference in OSA findings. Periodic limb movement index (PLMI) was elevated in 4/15 (26%). OSA is frequently identified on polysomnography in patients with SYS. The mean PLMI is elevated compared to normative data. Patients with SYS should have routine polysomnography screening due to high risk of sleep disorders.

Intrathecal morphine and sleep apnoea severity in patients undergoing hip arthroplasty: a randomised, controlled, triple-blinded trial

BackgroundIntrathecal morphine prolongs analgesia after surgery, but has been implicated in postoperative respiratory depression or apnoeic episodes. However, this has not been investigated in a prospective trial using respiratory polygraphy. This randomised controlled triple-blinded trial tested the hypothesis that intrathecal morphine increases sleep apnoea severity, measured using respiratory polygraphy. MethodsSixty subjects undergoing hip arthroplasty under spinal anaesthesia received either 15 mg isobaric bupivacaine 0.5% with 0.5 ml normal saline 0.9% (control group) or 15 mg isobaric bupivacaine 0.5% with 0.5 ml intrathecal morphine 100 μg (intrathecal morphine group). Respiratory polygraphy was performed before surgery and on the first and third postoperative nights. The primary outcome was the apnoea–hypopnoea index in the supine position (supine AHI) on the first postoperative night. Secondary outcomes included supine AHI on the third postoperative night, oxygen desaturation index (ODI), and ventilatory frequency during the first and third postoperative nights. ResultsOn the first postoperative night, mean (95% confidence interval) values for supine AHI were 20.6 (13.9–27.3) and 21.2 (12.4–30.0) events h−1 in the control and intrathecal morphine groups, respectively (P=0.90). There were no significant between-group differences for any of the secondary outcomes, except for a significantly higher central and mixed apnoea index preoperatively and significantly lower mean SpO2 on the third postoperative night in the control group. ConclusionsIntrathecal morphine did not increase sleep apnoea severity when measured using respiratory polygraphy. Of note, all patients had an increased number of apnoeic episodes on the third postoperative night. Clinical trial registrationNCT02566226.

Atrial fibrillation is associated with central sleep apnea in clinic patients undergoing diagnostic polysomnography.

IntroductionSleep apnea is highly prevalent in patients with atrial fibrillation (AF). Obstructive sleep apnea (OSA) is the most common type, and best studied in the context of AF. However, recent investigations have indicated that central sleep apnea (CSA) may be a risk factor for incident AF. We evaluated the burden of CSA events in patients referred for diagnostic polysomnography (PSG) and whether AF is associated with CSA.MethodsWe identified patients with and without a history of AF who underwent clinically indicated PSG in a matched manner. OSA was defined as obstructive apnea‐hypopnea index (AHI) ≥15/h, and CSA was defined as central apnea index (CAI) ≥5/h. The association between AF and CSA was evaluated using multivariable logistic regression.ResultsAmong 465 patients included, mean AHI was 25.5/h, and mean CAI was 1.7/h. OSA prevalence was 53.3%, while CSA prevalence was 8.4%. The prevalence of OSA in the AF and non‐AF groups (54.7% vs 52.0%, P = .56) was similar. CSA was more common in the AF group (12.3% vs 4.4%, P = .002). In multivariable analysis, AF (OR: 2.19 [1.02, 5.03], P = .05), male gender (OR: 2.5 [1.17, 5.84], P = .02), and older age (OR: 2.44, [1.16, 5.46], P = .02) were associated with CSA.ConclusionThough CSA is much less common than OSA in patients with AF, the presence of AF is independently associated with CSA.

Central sleep apnea is uncommon after stroke

Objective/backgroundStroke is often considered a risk factor for central sleep apnea (CSA). The goal of this study was to determine the prevalence and clinical correlates of CSA in patients with ischemic stroke. Patients/methodsIn this analysis, 1346 participants in the Brain Attack Surveillance in Corpus Christi (BASIC) project underwent a home sleep apnea test shortly after ischemic stroke. Respiratory events during sleep were classified as central apneas, obstructive apneas, or hypopneas. Central apnea index (CAI) was defined as number of central apneas divided by recording time. CSA was defined as CAI ≥5/hour with at least 50% of all scored respiratory events classified as central apneas. Demographics and co-morbidities were ascertained from the medical record. ResultsMedian CAI was 0/hour. Nineteen participants (1.4%) met criteria for CSA. Participants with CSA were more likely to be male, and had lower prevalence of obesity than participants without CSA. There was no association between CSA and other co-morbidities. ConclusionsCSA was uncommon in this large cohort of patients with recent ischemic stroke.

Central apnoeas and ticagrelor-related dyspnoea in patients with acute coronary syndrome.

Dyspnoea often occurs in patients with acute coronary syndrome (ACS) treated with ticagrelor compared with other anti-platelet agents and is a cause of drug discontinuation. We aimed to explore the contribution of central apnoeas (CA) and chemoreflex sensitization to ticagrelor-related dyspnoea in patients with ACS. Sixty consecutive patients with ACS, preserved left ventricular ejection fraction, and no history of obstructive sleep apnoea, treated either with ticagrelor 90 mg b.i.d. (n = 30) or prasugrel 10 mg o.d. (n = 30) were consecutively enrolled. One week after ACS, all patients underwent two-dimensional Doppler echocardiography, pulmonary static/dynamic testing, carbon monoxide diffusion capacity assessment, 24-h cardiorespiratory monitoring for hypopnoea-apnoea detection, and evaluation of the chemosensitivity to hypercapnia by rebreathing technique. No differences were found in baseline demographic and clinical characteristics, echocardiographic, and pulmonary data between the two groups. Patients on ticagrelor, when compared with those on prasugrel, reported more frequently dyspnoea (43.3% vs. 6.7%, P = 0.001; severe dyspnoea 23.3% vs. 0%, P = 0.005), and showed higher apnoea-hypopnoea index (AHI) and central apnoea index (CAI) during the day, the night and the entire 24-h period (all P < 0.001). Similarly, they showed a higher chemosensitivity to hypercapnia (P = 0.001). Among patients treated with ticagrelor, those referring dyspnoea had the highest AHI, CAI, and chemosensitivity to hypercapnia (all P < 0.05). Central apnoeas are a likely mechanism of dyspnoea and should be screened for in patients treated with ticagrelor. A drug-related sensitization of the chemoreflex may be the cause of ventilatory instability and breathlessness in this setting.

Do Cheyne and Stokes have an important message for modern‐day patients with heart failure? Yes, they do

Do <scp>C</scp>heyne and <scp>S</scp>tokes have an important message for modern‐day patients with heart failure? <scp>Y</scp>es, they do

Sleep-Disordered Breathing in Children with Prader-Willi Syndrome in Relation to Growth Hormone Therapy Onset

Objective: The aim of this study was to consider sleep apnea in Prader-Willi syndrome (PWS) children depending on age at growth hormone (GH) therapy onset. Study Design: We analyzed longitudinally cardiorespiratory polygraphy of 62 PWS children (aged 0–2.5 years at baseline). Twenty-one children (Group A) started GH-therapy during and 41 children (Group B) after their first year of life. Data were acquired before, at 3 and 6 months, then 1.2, 2.2, and 3.2 years after GH onset. Outcomes were determined with the obstructive apnea hypopnea index (OAHI), central apnea index (CAI), oxygen desaturation index (ODI), and by measuring obstructive sleep apnea (OSA) and peripheral blood oxygen saturation (SpO₂). Results: We observed no significant differences in OAHI, CAI, ODI, and SpO₂ depending on treatment onset. At baseline, 5/21 patients (23.8%) in Group A versus 15/41 patients (36.6%) in Group B showed pathological sleep apnea (OAHI ≥1.5). Pathological OSA increased significantly in Group A during the first 3 months of therapy but dropped below baseline after 1 year in both groups. ODI changed during GH therapy in both groups (from 4.0 to 2.6 in Group A, and 3.6 to 1.6 in Group B; baseline to 3.2 years; p < 0.05). Conclusions: OSA in PWS children appears to develop independently of treatment onset. Treatment may therefore safely be initiated early but should be accompanied by regular sleep analysis.

Upright Cheyne-Stokes Respiration in Patients With Heart Failure

BackgroundCheyne-Stokes respiration (CSR) is believed to only occur in supine and sleeping conditions, and thus, CSR treatment is applied to those specific states. Although CSR has also been described in patients with heart failure (HF) during wakefulness, its persistence in an upright position is still unknown. ObjectivesThe purpose of this study was to assess the predictors, clinical correlates, and prognostic value of diurnal CSR in upright position. MethodsOutpatients with systolic HF underwent a comprehensive evaluation, including short-term respiratory monitoring with a head-up tilt test to investigate the presence of upright CSR, assessment of chemoreflex response to hypoxia and hypercapnia, and 24-h cardiorespiratory recording. At follow-up, cardiac death was considered as the endpoint. ResultsOf 574 consecutive patients (left ventricular ejection fraction 32 ± 9%; age 65 ± 13 years; 80% men), 195 (34%) presented supine CSR only, 82 (14%) presented supine and upright CSR, and 297 patients (52%) had normal breathing. Patients with upright CSR had the greatest apnea-hypopnea and central apnea index (at daytime and nighttime), the worst hemodynamic profile and exercise performance, increased plasma norepinephrine and N-terminal pro–B-type natriuretic peptide, and chemosensitivity to hypercapnia, which was the only independent predictor of upright CSR (odds ratio: 3.96; 95% confidence interval [CI]: 1.45 to 10.76; p = 0.007 vs. normal breathing; odds ratio: 4.01; 95% CI: 1.54 to 10.46; p = 0.004 vs. supine CSR). At 8-year follow-up, patients with upright CSR had the worst outcome (log-rank = 14.05; p = 0.001) and the presence of upright CSR independently predicted 8-year cardiac death (hazard ratio: 2.39; 95% CI: 1.08 to 5.29; p = 0.032). ConclusionsUpright CSR in HF patients is predicted by increased chemosensitivity to hypercapnia and is associated with worse clinical conditions and with a greater risk of cardiac death.

Unobtrusive Screening of Central Sleep Apnea From Pressure Sensors Measurements: A Patient-Specific Longitudinal Study

Historically, the lack of patients’ sleep histories has caused low identification of sleep apnea (SA) and referral rates. Moreover, the costly and time-consuming nature of polysomnography (PSG) as a standard clinical test for detecting SA and the lack of sleep clinics has created a demand for suitable home-based monitoring devices. Pressure measurement using a pressure sensitive mat (PSM) can address the challenges found in current sleep-monitoring solutions. The noncontact PSM has a potential to replace obtrusive breathing sensors in the sleep lab and to be used as a prescreening tool for patients suspected of having SA. Applying classical support vector machine (SVM), this article presents a personalized system based on the measurements of each patient to detect central SA (CSA) events and monitor sleep characteristics longitudinally. For this purpose, sensor set-ups were installed in nine seniors’ homes to collect unsupervised pressure data in approximately one year ranging from 8 to 12 months. Cost-based and resampling-based approaches were examined to combat imbalanced data. The results showed that the cost-based method outperformed other methods. Next, the patient-specific system was used to determine the total number of CSA events, as well as their starting time and duration in each day. The SA severity was measured by the central apnea index (CAI). In addition, other sleep characteristics such as bed occupancy (BO), day clock, and night clock were extracted from the PSM measurements. The impact of longitudinal sleep monitoring could be in tracking SA treatment progression, and possibly providing information on the interaction between SA and other disease progressions.

0676 Long-term Effects Of Upper Airway Stimulation For Treatment Of Obstructive Sleep Apnea On Measurements Of Central And Mixed Apneas

Abstract Introduction Upper airway stimulation (UAS) of the hypoglossal nerve for obstructive sleep apnea (OSA) is well-tolerated and results in sustained reduction in the apnea-hypopnea index (AHI). Treatment-emergent CSA is reported to occur in 3.5-19.8% of OSA patients treated with CPAP. We aimed to examine the occurrence or emergence of central and mixed apneas in a cohort of participants that received UAS and were followed for 5 years post implantation. Methods The Stimulation Trial for Apnea Reduction (STAR) was a Phase III trial evaluating the safety and efficacy of UAS for CPAP-intolerant OSA. Major inclusion criteria were CPAP intolerance, AHI between 20-50, less than 25% central and mixed apneas and BMI &amp;lt;= 32. Polysomnography was performed at baseline, 12, 18, 36 and 60-month follow-up. Data were scored by a core lab and was then retrospectively analyzed via the STAR PSG database to measure the evolution of central and mixed apneas on UAS therapy. Results Baseline age was 54.5 ± 10.2 years, BMI was 28.4 ± 2.6 kg/m2 and 83% male (n=126). AHI data were non-normally distributed. Median AHI was 29.3/hr at baseline, that was reduced to 9/hr at 12-months and 6/hr at 60-months. Median central apnea index (CAI) was 0.8/hr at baseline, 0.4/hr at 12-months, and 0.2/hr at 60-months. Median mixed apnea index (MAI) was 0.2/hr at baseline, 0.7/hr at 12-months and 0.4/hr at 60-months. The 12- and 60-month CAI was significantly lower than baseline (p&amp;lt;0.05), but MAI was not. The percentage of central and mixed events remained stable throughout follow-up, approximately at 5% of the total AHI. Conclusion UAS reduced the overall AHI and results in a small but significant decrease in CAI. Given that OSA and CSA frequently co-exist, the role of UAS on reducing CSA in patients with combined OSA and CSA deserves further investigation. Support STAR study was sponsored by Inspire Medical Systems