Correlates of sleep-disordered breathing and Cheyne-Stokes respiration in patients with atrial fibrillation who have undergone pulmonary vein isolation.

Sleep disordered breathing (SDB) is a common comorbidity in patients with atrial fibrillation (AF). Patients undergoing pulmonary vein isolation (PVI) for AF have a high prevalence of SDB. In previous studies, some patients with AF had Cheyne-Stokes respiration (CSR). The aim of the present study was to assess the prevalence of SDB and the correlates of SDB severity and CSR in AF patients who have undergone PVI. The study was conducted using a single-center observational design. All participants underwent a home sleep apnea test (ApneaLink Air, ResMed, Australia), which could determine the severity of SDB as assessed by the apnea-hypopnea index (AHI) and the percentage of CSR (%CSR) pattern. 139 AF patients who underwent PVI were included in the study. Overall, 38 (27.3%) patients had no SDB (AHI < 5), 53 (38.1%) had mild SDB (5 ≤ AHI < 15), 33 (23.7%) had moderate SDB (15 ≤ AHI < 30), and 15 (10.8%) had severe SDB (AHI ≥ 30). Correlates of the increased AHI included male sex (ß = 0.23, p = 0.004), age (ß = 0.19, p = 0.020), high body mass index (ß = 0.31, p < 0.001), and ß blockers usage (ß = 0.18, p = 0.024). Conversely, correlates with the %CSR rate included male sex (ß = 0.18, p = 0.020), age (ß = 0.19, p = 0.015), non-paroxysmal AF (ß = 0.22, p = 0.008), and high glycohemoglobin A1c (ß = 0.36, p < 0.001) and N-terminal pro-brain natriuretic peptide (ß = 0.24, p = 0.005) levels. SDB is prevalent in patients with AF who have undergone PVI; predisposing factors for SDB include male sex, older age, and obesity. CSR occurs in patients with AF who have undergone PVI; predisposing factors for CSR include male sex, older age, high left ventricular filling pressure, and abnormal blood glucose level.

Ventricular assist devices and sleep-disordered breathing-A mechanical heart stimulating a sleepy brain.

Sleep-disordered breathing, including obstructive sleep apnea (OSA) and central sleep apnea (CSA), is common in severe heart failure (HF) patients. There is limited data on the effect of left ventricular assist devices (LVAD) on sleep apnea. We performed a retrospective review of 350 durable LVAD patients and found 5 with a history of pre- and post-LVAD sleep studies. All five patients had OSA, and three had concomitant CSA. We observed reduced apnea-hypopnea index following LVAD placement. This was due to a near abolishment of CSA in three mixed sleep apnea patients-as seen by a central apnea index improvement from an average of 25.9 ± 13.1 to 1.4 ± 2.5 events per hour (p = 0.063). LVAD placement was associated with an increase in thermodilution cardiac output from 2.7 ± 0.6 to 4.1 ± 1.1 L/min (p = 0.014). These findings support chemoreception physiology seen in patients with poor circulation and the effect of restoring this circulation with LVAD support.

The prevalence and polysomnographic characteristics of treatment-emergent central sleep apnea with obstructive sleep apnea.

PURPOSE: To investigate the prevalence of treatment-emergent central sleep apnea (TECSA) in individuals with obstructive sleep apnea syndrome (OSAS) during continuous positive airway pressure (CPAP) titration and assess their polysomnographic characteristics. METHODS: A total of 116 patients with OSAS who underwent full-night CPAP titration at the Sleep Laboratory of Adana City Research and Education Hospital from September 2017 to January 2018 were recruited for the study. The patients' polysomnographic data related to respiratory events and sleep stages were reviewed in a retrospective manner. RESULTS: While on CPAP titration, 20 of the 116 patients developed central sleep apnea (CSA). The prevalence of TECSA in the patients with OSAS was 17.2%, being separately determined as 16.3% and 2.2% for the male and female patients, respectively. In the baseline PSG, the groups did not statistically significantly differ in relation to the apnea hypopnea index (AHI), central apnea index (CAI), arousal index (AI), or oxygen desaturation index (ODI). However, the TECSA group had a significantly higher mean oxygen saturation value compared to the non-TECSA group (p = 0.01). The total AHI, CAI, and AI values of the TECSA group were significantly higher during the whole CPAP titration compared to the non-TECSA group. No significant difference was observed in the comparison of the two groups in relation to the titration pressure and ODI. CONCLUSION: TECSA is a phenomenon that can occur with obstructive sleep apnea treatment and mostly regress spontaneously following appropriate CPAP treatment. TECSA is observed at different rates of prevalence. In this study, the prevalence of TECSA was higher than previously reported.

Analysis by sex of safety and effectiveness of transvenous phrenic nerve stimulation.

PURPOSE: Little is known about sex differences in the treatment of central sleep apnea (CSA). Our post hoc analysis of the remede System Pivotal Trial aimed to determine sex-specific differences in the safety and effectiveness of treating moderate to severe CSA in adults with transvenous phrenic nerve stimulation (TPNS). METHODS: Men and women enrolled in the remede System Pivotal Trial were included in this post hoc analysis of the effect of TPNS on polysomnographic measures, Epworth Sleepiness Scale, and patient global assessment for quality of life. RESULTS: Women (n = 16) experienced improvement in CSA metrics that were comparable to the benefits experienced by men (n = 135), with central apneas being practically eliminated post TPNS. Women experienced improvement in sleep quality and architecture that was comparable to men post TPNS. While women had lower baseline apnea hypopnea index than men, their quality of life was worse at baseline. Additionally, women reported a 25-percentage point greater improvement in quality of life compared to men after 12 months of TPNS therapy. TPNS was found to be safe in women, with no related serious adverse events through 12 months post-implant, while men had a low rate of 10%. CONCLUSION: Although women had less prevalent and less severe CSA than men, they were more likely to report reduced quality of life. Transvenous phrenic nerve stimulation may be a safe and effective tool in the treatment of moderate to severe CSA in women. Larger studies of women with CSA are needed to confirm our findings. CLINICAL TRIAL REGISTRATION: ClinicalTrials.gov NCT01816776; March 22, 2013.

Effect of lateral position on rostral fluid shift and relationship to severity of Cheyne-Stokes respiration in heart failure patients.

PURPOSE: Lateral sleep position has a significant beneficial effect on the severity of Cheyne-Stokes respiration with central sleep apnea (CSR-CSA) in patients with heart failure (HF). We hypothesized that a reduction in rostral fluid shift from the legs in this position compared with the supine position may contribute to this effect. METHODS: In patients with CSR-CSA and an apnea-hypopnea index (AHI) ≥ 15/h (by standard polysomnography), uncalibrated leg fluid volume was measured in the supine, left lateral decubitus, and right lateral decubitus positions (in-laboratory assessment). The correlation between postural changes in fluid volume and corresponding changes in AHI was evaluated. Since there was no difference in both leg fluid volume and AHI between the right and left positions, measurements in these two conditions were combined into a single lateral position. RESULTS: In 18 patients with CSR-CSA, leg fluid volume increased by 2.7 ± 3.1% (p = 0.002) in the lateral position compared to the supine position, while AHI decreased by 46 ± 20% (p < 0.0001) with the same postural change. The correlation between postural changes in AHI and leg fluid volume was 0.22 (p = 0.42). Changes in leg fluid volume were a slow phenomenon, whereas changes in CSR-CSA severity were almost synchronous with changes in posture. CONCLUSION: Lateral position causes a reduction in rostral fluid shift compared to the supine position, but this change does not correlate with the corresponding change in CSR-CSA severity. The two changes occur on different time scales. These findings question the role of postural changes in rostral fluid shift as a determinant of corresponding changes in CSR-CSA severity.

Phrenic nerve stimulation for central sleep apnea: a single institution experience.

PURPOSE: Phrenic nerve stimulation (PNS) was approved by the Food and Drug Administration (FDA) to treat moderate to severe central sleep apnea. We report here, results of a retrospective study regarding our institutional outcomes at one year. In this study we evaluated the change in the apnea hypopnea index, epworth sleepiness score, and functional outcomes of sleep score at one year post implant. METHODS: This is a retrospective analysis of patients ≥ 18 years of age who had PNS implanted for moderate to severe CSA at the Ohio State University Wexner Medical Center apnea between Feb 1, 2018 to July 1, 2021. Sleep disordered breathing parameters and objective sleepiness as measured by the Epworth Sleepiness Scale (ESS) scores, and Functional Outcomes of Sleep Questionnaire (FOSQ) scores were assessed at baseline and one-year post-implant. RESULTS: Twenty-two patients were implanted with PNS at OSU between February 1, 2018 and May, 31, 2022. The AHI showed a statistically significant decrease from a median of 40 events/hour at baseline to 18 at follow-up (p-value = 0.003). The CAI decreased from 16 events/hour to 2 events/hour (p-value of 0.001). The obstructive apnea index, mixed apnea index, and hypopnea index did not significantly change. The ESS scores had a statistically significant improvement from a median score of 12 to 9 (p-value = 0.028). While the FOSQ showed a trend to improvement from 15.0 to 17.8, it was not statistically significant (p-value of 0.086). CONCLUSION: Our study found that PNS therapy for moderate to severe CSA improves overall AHI and CAI. Objective sleepiness as measured by the ESS also improved at one-year post implant.

Posterior fossa decompression in patients with Chiari malformation type 1: effect on sleep apnea and follow-up outcomes.

PURPOSE: Sleep apnea, posing significant health risks, is frequently associated with Chiari malformation (CM), characterized by cerebellar tonsil herniation through the foramen magnum. Central sleep apnea (CSA) in CM results from impaired brain-to-muscle signaling and requires treatment. Conversely, obstructive sleep apnea (OSA), arising from throat muscle relaxation, typically unrelated to CM, often coexists. This study evaluates the effectiveness of posterior fossa decompression (PFD) on sleep apnea. METHODS: A retrospective chart review was conducted of pediatric patients with CM-1 and sleep apnea who underwent PFD between April 1, 2004, and September 30, 2022. Data collected included demographics, clinical characteristics, adenotonsillectomy status, PFD details, and sleep study parameters like the apnea-hypopnea index and respiratory disturbance index. Statistical analysis assessed the surgery's impact on sleep apnea severity. RESULTS: The study included eleven patients, predominantly male (63.6%). All had OSA (100%), with 63.6% also having CSA. Preoperative sleep studies classified OSA severity as 36.4% mild, 18.2% moderate, and 45.5% severe, with no change post-surgery. CSA severity initially included seven mild cases, which became three mild, one moderate, and three resolved cases post-surgery. Among seven patients who had adenotonsillectomy before decompression, five showed no improvement in OSA severity post-surgery. CONCLUSION: This study elucidates the complex relationship between CM-1, sleep apnea, and PFD. The findings show the persistence of sleep apnea in some patients and highlight the need for continuous monitoring of these patients in order to optimize their care after surgery.

Sleep Apnea and Heart Failure-Current State-of-The-Art.

Sleep-disordered breathing (SDB), including obstructive and central sleep apnea, significantly exacerbates heart failure (HF) through adverse cardiovascular mechanisms. This review aims to synthesize existing literature to clarify the relationship between SDB and HF, focusing on the pathophysiological mechanisms, diagnostic challenges, and the effectiveness of treatment modalities like continuous positive airway pressure (CPAP) and adaptive servo-ventilation ASV. We analyzed peer-reviewed articles from 2003 to 2024 sourced from PubMed, EMBASE, Scopus, and Web of Science databases. The prevalence of SDB in HF patients is high, often underdiagnosed, and underappreciated. Management strategies, including CPAP and ASV, have been shown to mitigate symptoms and improve cardiac function. However, despite the availability of effective treatments, significant challenges in screening and diagnosis persist, affecting patient management and outcomes. DB significantly impacts HF prognosis. Enhanced screening strategies and broader utilization of therapeutic interventions like CPAP and ASV are essential to improve the management and outcomes of HF patients with concomitant SDB. Future research should focus on refining diagnostic and treatment protocols to optimize care for HF patients with SDB.

Circulating miR-133a-3p defines a low-risk subphenotype in patients with heart failure and central sleep apnea: a decision tree machine learning approach.

BACKGROUND: Patients with heart failure with reduced ejection fraction (HFrEF) and central sleep apnea (CSA) are at a very high risk of fatal outcomes. OBJECTIVE: To test whether the circulating miRNome provides additional information for risk stratification on top of clinical predictors in patients with HFrEF and CSA. METHODS: The study included patients with HFrEF and CSA from the SERVE-HF trial. A three-step protocol was applied: microRNA (miRNA) screening (n = 20), technical validation (n = 60), and biological validation (n = 587). The primary outcome was either death from any cause, lifesaving cardiovascular intervention, or unplanned hospitalization for worsening of heart failure, whatever occurred first. MiRNA quantification was performed in plasma samples using miRNA sequencing and RT-qPCR. RESULTS: Circulating miR-133a-3p levels were inversely associated with the primary study outcome. Nonetheless, miR-133a-3p did not improve a previously established clinical prognostic model in terms of discrimination or reclassification. A customized regression tree model constructed using the Classification and Regression Tree (CART) algorithm identified eight patient subphenotypes with specific risk patterns based on clinical and molecular characteristics. MiR-133a-3p entered the regression tree defining the group at the lowest risk; patients with log(NT-proBNP) ≤ 6 pg/mL (miR-133a-3p levels above 1.5 arbitrary units). The overall predictive capacity of suffering the event was highly stable over the follow-up (from 0.735 to 0.767). CONCLUSIONS: The combination of clinical information, circulating miRNAs, and decision tree learning allows the identification of specific risk subphenotypes in patients with HFrEF and CSA.

Sleep disorders and polysomnography findings in patients with autoimmune encephalitis.

BACKGROUND: Sleep disorders in patients with autoimmune encephalitis (AE) are increasingly reported. Early recognition and treatment have significant importance regarding the potential of sleep disorders' effect on morbidity and even mortality. There are a limited number of studies related to polysomnography (PSG) in these patients. Here, we report the clinical and PSG data of patients with AE and sleep disorders, with a particular interest in sleep-related breathing disorders (SRBD). METHODS: Seventeen patients with diagnosed AE and acute or subacute onset sleep complaints who underwent video-electroencephalography-PSG recordings in our tertiary center were investigated. RESULTS: The mean age was 50, with eight females and nine males. The detected antibodies were against leucine-rich glioma-inactivated 1(LGI-1) in 6, anti-contactin-associated protein-2(CASPR2) in 3, voltage-gated potassium channel complex antigens(VGKC) in 1, anti-glycine in 1, dipeptidyl-peptidase-like protein-6(DPPX) in 1, anti-Hu in 1, and anti-amphiphysin in 1. All commercially available and known autoimmune encephalitis-related antibodies were negative in 3 of the patients. Final diagnosis after PSG was circadian rhythm sleep disorder (n = 3), periodic limb movement disorder (n = 3), insomnia (n = 5), central apnea with or without Cheyne-Stokes breathing (CSB) (n = 4), obstructive sleep apnea (OSA) (n = 4), non-rapid eye movement (NREM) and REM parasomnia (n = 8), faciobrachial dystonic seizures (n = 2), and subclinical seizures (n = 1). Sleep microstructure was disrupted in 9, REM periods without atonia occurred in 4, and brief sleep fragments consisting of theta activity interspersed with faster rhythms existed in 7 patients. Nearly half of our patients (47%) had SRBD, and the mean apnea-hypopnea index (AHI) was 14. CONCLUSIONS: Sleep disorders are frequent and essential components of AEs. Systematic clinical questionnaires and routine PSG assessments would significantly impact the correct diagnosis and proper treatment of SRBD and the overall prognosis of AE.

Phrenic nerve stimulation for the treatment of central sleep apnea in patients with heart failure.

OBJECTIVE: Central sleep apnea (CSA) is associated with increased morbidity and mortality in patients with heart failure (HF). We aimed to explore the effectiveness of phrenic nerve stimulation (PNS) on CSA in patients with HF. METHODS: This was a prospective and non-randomized study. The stimulation lead was inserted into the right brachiocephalic vein and attached to a proprietary neurostimulator. Monitoring was conducted during the implantation process, and all individuals underwent two-night polysomnography. RESULTS: A total of nine subjects with HF and CSA were enrolled in our center. There was a significant decrease in the apnea-hypopnea index (41 ± 18 vs 29 ± 25, p = 0.02) and an increase in mean arterial oxygen saturation (SaO2) (93% ± 1% vs 95% ± 2%, p = 0.03) after PNS treatment. We did not observe any significant differences of oxygen desaturation index (ODI) and SaO2 < 90% (T90) following PNS. Unilateral phrenic nerve stimulation might also categorically improve the severity of sleep apnea. CONCLUSION: In our non-randomized study, PNS may serve as a therapeutic approach for CSA in patients with HF.

Adaptive servo-ventilation and mortality in patients with systolic heart failure and central sleep apnea: a single-center experience.

BACKGROUND: Central sleep apnea (CSA) is associated with increased mortality and morbidity in patients with heart failure with reduced ejection fraction (HFrEF). Treatment of CSA with a certain type of adaptive servo-ventilation (ASV) device that targets minute ventilation (ASVmv) was found to be harmful in these patients. A newer generation of ASV devices that target peak flow (ASVpf) is presumed to have different effects on ventilation and airway patency. We analyzed our registry of patients with HFrEF-CSA to examine the effect of exposure to ASV and role of each type of ASV device on mortality. METHODS: This is a retrospective cohort study in patients with HFrEF and CSA who were treated with ASV devices between 2008 and 2015 at a single institution. Mortality data were collected through the institutional data honest broker. Usage data were obtained from vendors' and manufacturers' servers. Median follow-up was 64 months. RESULTS: The registry included 90 patients with HFrEF-CSA who were prescribed ASV devices. Applying a 3-h-per-night usage cutoff, we found a survival advantage at 64 months for those who used the ASV device above the cutoff (n = 59; survival 76%) compared to those who did not (n = 31; survival 49%; hazard ratio 0.44; CI 95%, 0.20 to 0.97; P = 0.04). The majority (n = 77) of patients received ASVpf devices with automatically adjusting end-expiratory pressure (EPAP) and the remainder (n = 13) received ASVmv devices mostly with fixed EPAP (n = 12). There was a trend towards a negative correlation between ASVmv with fixed EPAP and survival. CONCLUSION: In this population of patients with HFrEF and CSA, there was no evidence that usage of ASV devices was associated with increased mortality. However, there was evidence of differential effects of type of ASV technology on mortality.

Transvenous phrenic nerve stimulation: setting up a clinical program.

BACKGROUND: Central sleep apnea (CSA) is a form of sleep-disordered breathing caused by a lack of the drive to breathe during sleep. Phrenic nerve stimulation (PNS) was approved in 2017 for treatment of moderate to severe CSA. However, information on setting up a successful PNS program is lacking. We describe our institution's program to provide a framework to bridge the gap between clinical research and clinical application for PNS therapy. METHODS: The PNS program was created as a joint program between cardiology and sleep medicine. The program team included cardiologists, sleep medicine specialists, advanced practice providers, clinic managers, and staff who worked together in the evaluation, implantation, and management of patients. RESULTS: Thus far, 33 patients have been implanted at our institution. We have noted resolution of central apneas with PNS and improvement in patient sleep symptoms. The multidisciplinary clinic with cardiology and sleep medicine has led to high patient satisfaction and has facilitated a cohesive relationship between implant and management teams. CONCLUSIONS: PNS therapy is an effective treatment option for CSA. While the therapy treats central apneas, it will not affect upper airway obstruction. Proper patient identification is important and cooperative management between cardiology and sleep medicine enhances patient care and experience. Challenges of establishing a multidisciplinary program include identification of providers, clinic space, and scheduling. Once established, the program provides an important service to a vulnerable patient population.

Loop gain response to increased cerebral blood flow at high altitude.

PURPOSE: To compare loop gain (LG) before and during pharmacological increases in cerebral blood flow (CBF) at high altitude (HA). Loop gain (LG) describes stability of a negative-feedback control system; defining the magnitude of response to a disturbance, such as hyperpnea to an apnea in periodic breathing (PB). "Controller-gain" sensitivity from afferent peripheral (PCR) and central-chemoreceptors (CCR) plays a key role in perpetuating PB. Changes in CBF may have a critical role via effects on central chemo-sensitivity during sleep. METHODS: Polysomnography (PSG) was performed on volunteers after administration of I.V. Acetazolamide (ACZ-10mg/kg) + Dobutamine (DOB-2-5 µg/kg/min) to increase CBF (via Duplex-ultrasound). Central sleep apnea (CSA) was measured from NREM sleep. The duty ratio (DR) was calculated as ventilatory duration (s) divided by cycle duration (s) (hyperpnea/hyperpnea + apnea), LG = 2π/(2πDR-sin2πDR). RESULTS: A total of 11 volunteers were studied. Compared to placebo-control, ACZ/DOB showed a significant increase in the DR (0.79 ± 0.21 vs 0.52 ± 0.03, P = 0.002) and reduction in LG (1.90 ± 0.23 vs 1.29 ± 0.35, P = 0.0004). ACZ/DOB increased cardiac output (CO) (8.19 ± 2.06 vs 6.58 ± 1.56L/min, P = 0.02) and CBF (718 ± 120 vs 526 ± 110ml/min, P < 0.001). There was no significant change in arterial blood gases, minute ventilation (VE), or hypoxic ventilatory response (HVR). However, there was a reduction of hypercapnic ventilatory response (HCVR) by 29% (5.9 ± 2.7 vs 4.2 ± 2.8 L/min, P = 0.1). CONCLUSION: Pharmacological elevation in CBF significantly reduced LG and severity of CSA. We speculate the effect was on HCVR "controller gain," rather than "plant gain," because PaCO2 and VE were unchanged. An effect via reduced circulation time is unlikely, as the respiratory-cycle length did not change.

Effect of Zolpidem on nocturnal arousals and susceptibility to central sleep apnea.

PURPOSE: Arousals may contribute to the pathogenesis of sleep-disordered breathing (SDB) and central sleep apnea (CSA). We aimed to determine the effect of the nonbenzodiazepine hypnotic zolpidem on the frequency of respiratory-related arousals and central apnea in patients with moderate-to-severe SDB. We hypothesized that zolpidem decreases the severity of SDB by decreasing the frequency of respiratory-related arousals. METHODS: Patients with apnea-hypopnea index ≥ 15 events/hour and central apnea-hypopnea index ≥ 5 events/hour underwent a sleep study on zolpidem 5 mg and a sleep study with no medication in a randomized order. The respiratory arousal index was compared between the two studies using a randomized crossover design. Sleep, respiratory, and physiologic parameters, including the CO2 reserve and the respiratory arousal threshold, were also compared. RESULTS: Eleven participants completed the study. Compared to no treatment, zolpidem reduced the respiratory arousal index (39.7 ± 7.7 vs. 23.3 ± 4.4 events/h, P = 0.031). Zolpidem also lowered the total apnea-hypopnea index (55.6 ± 8.5 vs. 41.3 ± 7.5 events/hour, P = 0.033) but did not affect other clinical and physiologic parameters. Compared to control, zolpidem did not widen CO2 reserve (- 0.44 ± 1.47 vs. - 0.63 ± 0.86 mmHg, P = 0.81). The respiratory arousal threshold did not show a significant change on zolpidem compared to control (- 8.72 ± 2.1 vs. - 8.25 ± 2.81 cmH2O, P = 0.41). CONCLUSION: Nocturnal arousals and overall SDB severity were reduced with a single dose of zolpidem in patients with moderate-to-severe sleep-disordered breathing with increased susceptibility for central apnea. Zolpidem did not widen the CO2 reserve or increase the arousal threshold. TRIAL REGISTRATION: Clinicaltrials.gov. Sleep and Breathing in the General Population - Chemical Stimuli (NCT04720547).

Contribution of central sleep apnea to severe sleep apnea hypopnea syndrome.

PURPOSE: Central sleep apnea (CSA) is usually distinguished from obstructive sleep apnea (OSA). In fact, CSA is often a component of severe sleep apnea hypopnea syndrome (SAHS), rather than occurring alone. We investigated the clinical characteristics and polysomnography (PSG) parameters of CSA components in patients with severe SAHS. METHODS: The clinical characteristics and PSG parameters were retrospectively analyzed. RESULTS: Pure or dominant CSA was rare (5% of all patients). Of all patients with CSA, 72% also exhibited other apnea subtypes that contributed to severe SAHS. Among patients with severe SAHS, those with CSA were more likely than others to be older; thinner; exhibit higher prevalences of comorbid coronary heart disease, arrhythmia, and heart failure; a higher apnea/hypopnea index (AHI); mixed apnea index (MAI); an elevated oxygen desaturation index (ODI); and more nighttime oxygen saturation levels < 90%. Multivariate logistic regression analysis revealed that older age, comorbid arrhythmia or heart failure, and an elevated ODI were independently associated with CSA. CONCLUSION: Patients who complain of snoring or apnea may be better evaluated by comprehensive PSG prior to treatment if they are old, show greater hypoxia, or suffer from arrhythmia and/or heart failure, because such patients are more likely than others to exhibit CSA.

Clinical and financial impact of sleep disordered breathing on heart failure admissions.

BACKGROUND: The impact of sleep disordered breathing (SDB) on heart failure (HF) is increasingly recognized. However, limited data exist in support of quantification of the clinical and financial impact of SDB on HF hospitalizations. METHODS: A sleep-heart registry included all patients who underwent inpatient sleep testing during hospitalization for HF at a single cardiac center. Readmission data and actual costs of readmissions were obtained from the institutional honest broker. Patients were classified based on the inpatient sleep study as having no SDB, obstructive sleep apnea (OSA), or central sleep apnea (CSA). Cumulative cardiac readmission rates and costs through 3 and 6 months post-discharge were calculated. Unadjusted and adjusted (age, sex, body mass index, and left ventricular ejection fraction) modeling of cost was performed. RESULTS: The cohort consisted of 1547 patients, 393 (25%) had no SDB, 438 (28%) had CSA, and 716 (46%) had OSA. Within 6 months of discharge, 195 CSA patients (45%), 264 OSA patients (37%), and 109 no SDB patients (28%) required cardiovascular readmissions. Similarly, 3- and 6-month mortality rates were higher in both SDB groups than those with no SDB. Both unadjusted and adjusted readmission costs were higher in the OSA and CSA groups compared to no SDB group at 3 and 6 months post-discharge with the CSA and OSA group costs nearly double (~ $16,000) the no SDB group (~ $9000) through 6 months. INTERPRETATION: Previously undiagnosed OSA and CSA are common in patients hospitalized with HF and are associated with increased readmissions rate and mortality.

Concurrent hypoglossal and phrenic nerve stimulation in patients with obstructive and treatment emergent central sleep apnea.

BACKGROUND: Patients with obstructive or central sleep apnea are primarily treated with positive airway pressure treatment. There are novel implantable options targeting either obstructive sleep apnea using hypoglossal nerve stimulation (HNS) or central sleep apnea using phrenic nerve stimulation (PNS). METHODS: Patients with sleep apnea were implanted with both HNS and PNS devices, and their response to each therapy was monitored using home sleep tests as well as Epworth Sleepiness scale (ESS). RESULTS: We evaluated our concurrent neurostimulation approach in two patients. Both patients were implanted with two neuromodulation devices: The first case suffered from treatment emergent central sleep apnea after HNS activation for primarily obstructive sleep apnea (apnea-hypopnea index/AHI 54/h). The central portion resolved under PNS (AHI 23.7/h). The second case suffered from predominantly central sleep apnea (AHI 82/h). Here, the PNS device was implanted first, resulting in a subsequent reduction of the central portion. The residual obstructive sleep apnea was addressed using HNS (AHI 5.4/h). No interaction between the HNS and PNS systems was noticed in either of the two patients. CONCLUSIONS: In selected cases, a concurrent treatment with hypoglossal and phrenic nerve stimulation may lead to improvement of sleep apnea and patient satisfaction in a safe manner.

Remede Systems: Transvenous Pacing of the Phrenic Nerve.

The remede System (ZOLL Medical, Minnetonka, MN; Fig 1), which was approved by the Food and Drug Administration in October of 2017, is a transvenous device that stimulates the phrenic nerve for the treatment of central sleep apnea, which is often associated with heart failure and atrial fibrillation. Given the similarity in implantation procedure to pacemakers and implantable cardioverter/defibrillators, the remede System implantation often occurs in the electrophysiology laboratory. Despite the transvenous nature and close proximity to cardiac structures on radiographic imaging, the remede System does not have any cardiac pacing function/antiarrhythmia therapies, and it is important for an anesthesiologist to be able to recognize and manage such a device if they were to come across one preoperatively.

Is adenotonsillectomy effective in improving central apnea events in patients with obstructive sleep apnea? A systematic review and meta-analysis.

PURPOSE: To evaluate the effects of adenotonsillectomy on improving central sleep apnea events in children with obstructive sleep apnea (OSA). METHODS: We searched four online databases for relevant articles published from inception until October 2022. We included studies that measured the number of central apnea events per sleep and central apnea-hypopnea index (CAHI) or central apnea index (CAI) scores in children with OSA before and after adenotonsillectomy. Our primary outcomes were changes in CAI scores, the number of central apnea events per sleep, and CAHI scores after surgery. Our secondary outcomes were changes in total and mixed apnea events, improvement of sleep outcomes, and differences in oxygen or carbon dioxide saturation during sleep. We performed meta-analyses by pooling the mean changes of all included studies with a 95% confidence interval using Stata 17. Subsequently, we performed subgroup analyses based on the presence of comorbidities. RESULTS: We included 22 studies comprising 1287 patients. Central and total sleep apnea parameters, except for CAHI and mixed apnea index scores, showed significant improvements after surgery. In addition, all respiratory parameters and second and third stages of non-rapid eye movement sleep showed significant postsurgical improvements. Patients with comorbidities showed significant improvements only in the total apnea-hypopnea index, oxygen desaturation index, and minimal oxygen saturation. CONCLUSION: Adenotonsillectomy improves central apnea events in patients with OSA but not in those with comorbidities.