Central and mixed apneas in children with obstructive sleep apnea: effect of adenotonsillectomy.

PURPOSE: Investigate the effect of adenotonsillectomy on mixed apnea index (MAI) and central apnea index (CAI) in children with moderate-to-severe obstructive sleep apnea syndrome (OSAS). METHODS: Observational retrospective analysis of polysomnographic data in children diagnosed with moderate-to-severe OSAS and without comorbidity, submitted to adenotonsillectomy. RESULTS: Data were available for 80 children, 55 boys and 25 girls, with a median age of 3.6 years (2.1-5.9). Before surgery AHI was 14.1 (11.0-18.4) per hour, with a median preoperative OAI of 7.1 (4.1-10.6), MAI of 1.2 (0.6-1.6) and CAI of 1.0 (0.4-2.0). Adenotonsillectomy caused significant improvements in MAI, from 1.2 (0.6-1.6) to 0.5 (0.1-0.8) (p < 0.001) and CAI from 1.0 (0.4-2.0) to 0.5 (0.1-0.9) (p < 0.001). This represents a normalization of MAI in 91.7% and CAI in 75.6% of children that had an abnormal value prior surgery. CONCLUSION: Non obstructive apneas are common in children with OSAS. Adenotonsillectomy caused significant decrease not only in OAI, but also in MAI and CAI in children with moderate-to-severe OSAS.

Effect of adenotonsillectomy on central sleep apnea: A scoping review.

OBJECTIVE: The purpose of this study was to assess the effects of adenotonsillectomy (A&T) on reducing central sleep apnea (CSA) in children and adolescents with obstructive sleep apnea (OSA). METHODS: A review of the PubMed database was conducted. Two researchers independently reviewed the articles from the literature search and selected papers for further review if they met inclusion criteria. Included studies were prospective studies and case series whose patients were children 18 years or younger undergoing adenotonsillectomy for obstructive sleep apnea with reported pre and postoperative central apnea indexes (CAI). RESULTS: Of the 107 articles initially identified, 18 underwent full length review, and ultimately 15 for final review. All studies reported marked improvement of central sleep apnea indexes after adenotonsillectomy. Two studies found resolution of CSA in 66.7 % and 73.7 % of patients respectively. The remaining four studies found significant reductions in CAI in 43.9 %-93 % of patients. The degree of reduction varied from 40.9 % to 80 %. DISCUSSION: Adenotonsillectomy improves and at times resolves CSA in pediatric patients with concomitant OSA.

Management of Sleep Apnea in Children with Chiari I Malformation: A Retrospective Study.

INTRODUCTION: The literature indicates that decompression of Chiari I malformations (CM-1) may resolve symptoms of sleep apnea. This study aims to identify the incidence of obstructive sleep apnea (OSA), central sleep apnea (CSA), and mixed sleep apnea in a cohort of pediatric CM-1 patients treated at our institution. We also assessed apnea-hypopnea index and symptomatology before and after surgery to investigate if Chiari decompression is a viable treatment for sleep apnea in CM-1 patients. Improvement relative to ENT surgical intervention was also considered. METHODS: We identified 75 patients who underwent polysomnography (PSG) from our database of 465 CM-1 patients. Sleep apnea diagnosis was based on the sleep physician's overall interpretation of the PSG. Symptomatology pre- and post-surgery was analyzed. RESULTS: Of the 75 CM-1 patients that underwent PSG, 23 were diagnosed with sleep apnea. Sixteen had OSA, 6 had CSA, and 1 had mixed apnea. Twelve OSA patients received ENT intervention. Eight improved and 2 further improved after Chiari decompression. Of the 4 patients that did not improve, one of those later improved following Chiari decompression. Of the 6 CSA patients, 2 underwent Chiari decompression, but only one improved. The mixed apnea patient underwent several ENT interventions that did not relieve symptoms but improved following Chiari decompression. DISCUSSION/CONCLUSIONS: Based on our results, sleep apnea in CM-1 patients may be obstructive, central, or mixed and is likely multifactorial. A multidisciplinary approach to the management of these patients is important, including neurosurgery, otolaryngology, and sleep medicine. Future prospective studies will lend further insight into this condition and its management.

Improvement in Central Sleep Apnea Following Adenotonsillectomy in Children.

OBJECTIVE: Previous studies examining changes in central sleep apnea (CSA) following adenotonsillectomy (T&A) performed for obstructive sleep apnea (OSA) in children have been limited by sample size and analysis of only certain populations. The aim of this study was to determine whether CSA improves following T&A and what factors mediate this change. METHODS: This was a retrospective case series from 1994 to 2020 of children undergoing primary T&A for OSA (obstructive apnea-hypopnea index ≥1) with CSA (central apnea index [CAI] ≥1) and preoperative and postoperative polysomnograms within 12 months of T&A. Polysomnograms were analyzed for improvement in CSA, defined as: 1) if preoperative CAI >5, a postoperative CAI <5; or 2) if preoperative CAI <5, a postoperative CAI <1. RESULTS: One hundred twenty-three patients were included. Median age was 5.5 years (interquartile range, 2.9-8.4). Most patients were overweight/obese (58.5%). Nineteen (15.4%) had a syndromic condition. Preoperative CAI was ≥5 in 21 (17.1%) patients. CAI significantly decreased following T&A (preoperative 2.1, postoperative 0.4; P < .001). Thirty-two (26.0%) patients had CSA postoperatively. Improvement in the microarousal index and older age were significantly associated with improvement in CSA. CONCLUSIONS: T&A led to resolution of CSA in most children with OSA. Improvement in the microarousal index was associated with improvement in CAI, suggesting that preoperative central apneas may be postarousal and thus resolve following T&A. LEVEL OF EVIDENCE: 4 Laryngoscope, 132:478-484, 2022.

[Treatment approach to apnestic breathing in a patient with vocal cord paralysis due to Arnold Chiari malformation and tracheostomy]. / Arnold Chiari malformasyonu nedeniyle vokal kord paralizisi gelisen ve trakeostomi takilan hastada apnöstik solunuma tedavi yaklasimi.

Arnold Chiari malformation (ACM) is herniation of brain stem structures, especially cerebellar tonsils, from the foramen magnum into the cervical spinal canal. Sleep-related respiratory disorders are reported at a higher rate in this patient group than the general population, at about 60-75%. A 43-year-old male patient was diagnosed with ACM type 1.5 at the center where he applied with complaints of weakness in the extremities, speech disorder and syncope triggered by coughing, and a decompression of posterior fossa (PFD) was applied to the patient. Since 2018, the apnea attacks, which were able to be 6-7 times a night every night, last in 30 seconds, with eyes open, inactivity and bruising, have started in the patient, so in all night-time polysomnography (PSG) examination for diagnostic purpose, apnestic breathing including continuous, central and mixed type apneas in sleep and wakefulness was detected. Different modes (CPAP, BPAP-S/T, ASV) were tried with the cannula placed on the tracheostomy in the PSG performed for non-invasive mechanical ventilation therapy, but none alone was effective. In the patient, whom IVAPS/AVAPS mode was tried, all abnormal breathing events, irregular apnetic breathing pattern and oxygen desaturations were effectively controlled in all positions, wakefulness and all sleep stages with pressure support, respiratory rate and tidal volume support. PFD is recommended as the first-line treatment for the treatment of obstructive or central type apneas in ACM; Information on non-invasive mechanical ventilation therapy is insufficient. In this case, we aimed to present the difficulties in the diagnosis and treatment of sleep-related respiratory disorders in a patient whom ACM diagnosed, PFD was applied but underwent permanent trachoestomy due to bilateral vocal cord paralysis.

Clinical features of children with Haddad syndrome: A single-center experience.

BACKGROUND/PURPOSE: Haddad syndrome (HS) is a very rare disease considered a form of neurocristopathy. It is characterized by a combination of congenital central hypoventilation syndrome (CCHS) and Hirschsprung's disease (HD). We report the clinical features and disease progression of HS to provide better care for HS patients by achieving an earlier diagnosis and optimal treatment. METHODS: Medical records of patients diagnosed with HS from 2005 to 2016 were retrospectively reviewed. Demographic data including gestational age, birth weight and height, and paired-like homeobox 2b (PHOX2B) gene mutation were collected. RESULTS: Seven males and three females were identified (mean gestational age 39.76 ±â€¯1.49 weeks, mean birth weight 3117.5 ±â€¯288.9 g). PHOX2B gene mutation was identified in all patients. Immediate ventilation care after birth was required in five patients due to poor respiration. The current median age of the children is 5.4 years (range, 1.8-10.1). Tracheostomy was performed in nine patients. Eight patients required sleep ventilation and two patients, 24-h continuous ventilation support. Six patients showed rectosigmoid aganglionosis and four patients exhibited total colonic aganglionosis, of these one had aganglionosis extended to the distal small bowel. Soiling was observed in seven patients (5 with laparoscopy-assisted transanal endorectal pull-through and 2 with Duhamel procedure) and one patient showed grade 2 constipation with Duhamel procedure. Six patients had developmental delay. All patients are alive. CONCLUSIONS: HS may require lifelong medical care. This study could be helpful to understand the clinical features of HS including associated abnormalities and disease progression. By assisting to understand the clinical features, we could provide better care for HS patients by achieving an earlier diagnosis and appropriate treatment. TYPE OF STUDY: Prognosis study. LEVEL OF EVIDENCE: Level IV.

Central sleep apnea in children with obstructive sleep apnea syndrome and improvement following adenotonsillectomy.

BACKGROUND: Although the pathogenesis of central and obstructive events seems to be different, these two entities may somehow be related. We aimed to determine whether, as reported in previous research, the number of central sleep apnea (CSA) cases in a population of children with obstructive sleep apnea syndrome (OSAS) was greater than in patients without obstructive events, and if CSA worsens with increasing OSAS severity. As a second objective, we analyzed changes in central apnea index (CAI) after adenotonsillar surgery compared to changes when no surgery has been performed. METHODS: We retrospectively reviewed nocturnal polysomnography (PSG) data from children between 1 and 14 years of age with no neurological conditions or syndromes. Patients with CAI values greater than 5 per hour were diagnosed as having CSA. Improvements of greater than 50% in CAI on repeat PSG were considered to represent a real change. RESULTS: Data were available from 1279 PSG studies, resulting in 72 children with a CAI greater than 5 per hour (5.6%). Patients with OSAS showed a higher CAI (2.16) compared with those without OSAS (1.17), and this correlation increased with higher degrees of obstructive apnea severity. When adenotonsillectomy was performed due to OSAS, the CAI decreased by 1.37. The average decrease in PSG values was only 0.38 in cases where no surgery was performed. CONCLUSION: The results of this study suggest that although CSA is perceived to be mostly associated with central nervous system ventilatory control, there may be a connection with airway obstruction and in children with CSA and OSA diagnosis adenotonsillectomy may improve both conditions.

Emergence of Central Sleep Apnea Events After Maxillomandibular Advancement Surgery for Obstructive Sleep Apnea.

PURPOSE: Central sleep apnea (CSA) can develop after the treatment of obstructive sleep apnea (OSA) with continuous positive airway pressure (CPAP). No studies have identified whether treatment of OSA with maxillomandibular advancement surgery (MMA) can result in CSA. The purpose of our study was to determine the incidence and clinical significance of CSA emerging after MMA surgery to treat OSA. PATIENTS AND METHODS: A retrospective review was conducted of all patients who had undergone MMA surgery for OSA at the Department of Oral and Maxillofacial Surgery at the QEII Health Sciences Centre (Halifax, NS, Canada) from 1996 through 2016. All patients with preoperative level 1 polysomnography and follow-up level 1 study results available at least 6 months postoperatively were included the present study. The pre- and postoperative central apnea index (CAI) results were compared. RESULTS: A total of 113 patients (84 men and 29 women) with an average age of 44.0 years were included in the present study. In 35 patients (31.0%), the emergence of CSA events were recorded on postoperative polysomnograms. Only 2 of the 113 patients experienced the emergence of clinically significant postoperative CSA (CAI >5). In our patient cohort, gender (P = .085), patient age (P = .238), and preoperative (P = .716) and postoperative (P = .209) Apnea-Hypopnea Index (AHI) results correlated with the postoperative development of CSA events after MMA surgery. The mean AHI values had decreased from 41.4 to 8.7 in all patients treated with MMA in our study. CONCLUSIONS: The emergence of CSA events occurred in 31% of patients after OSA treatment with MMA surgery. The rate of clinically significant CSA events emerging after MMA surgery in our study was 1.8%. These findings help to support the use of MMA surgery for OSA as a reasonable treatment alternative for patients unable to tolerate CPAP.

Ictal Central Apnea (ICA) may be a useful semiological sign in invasive epilepsy surgery evaluations.

INTRODUCTION: Ictal central apnea (ICA) occurs in up to 44% focal seizures (temporal > extratemporal) and precedes scalp electrographic (EEG) seizure onset in 54% of them. Central apnea can be elicited by electrical stimulation of mesial temporal structures (amygdala, hippocampus, and anteromesial parahippocampal and fusiform gyri), known symptomatogenic anatomical substrates for ICA. We aimed to analyze ICA value as an early semiological sign in invasive evaluation of suspected mesial temporal lobe epilepsy (MTLE). METHODS: We examined seizure records of intractable, suspected MTLE patients undergoing intracranial EEG (ICEEG) evaluations who had simultaneous respiratory belts with artifact-free signal. RESULTS: We analyzed 32 seizures (11 patients). ICA was seen in 22/32 (68.7%) seizures in 9 patients, was the first clinical manifestation in all of them, and the only clinical sign in 5/32 (15.6%). ICA onset occurred simultaneously or after ICEEG seizure onset in 20/22 (91%) seizures by 4.9 +4.6 [0-14] seconds. In one patient with bilateral amygdalar and hippocampal implantation, ICA occurred before ICEEG seizure onset, indicating seizure discharge in an untargeted, probably extra amygdalohippocampal, symptomatogenic location. CONCLUSIONS: ICA incidence in mesial temporal lobe (MTL) seizures is 68.7%. ICA is often the first clinical sign and sometimes the only clinical manifestation in MTLE, but usually goes unrecognized. ICA recognition may help anatomo-electro-clinical localization of clinical seizure onset to known symptomatogenic areas. ICA preceding ICEEG onset may indicate inadequate putative epileptogenic zone coverage, and may impact surgical outcomes. Respiratory monitoring in surgical evaluations is of critical importance and should be carried out as standard of care.

Obstructive sleep disordered breathing in children - an important problem in the light of current European guidelines.

Obstructive sleep-disordered breathing (SDB) is a common clinical problem. An unrecognized and untreated SDB is a serious threat for an intensively developing organism of a child. The consequences of SDB include cardiovascular and neurological complications, growth disorders and enuresis. Therefore, SDB in children becomes an important subject of many scientific investigations, publications, and congresses. In 2015 the European Respiratory Society Task Force published a document concerning the conclusions about the diagnostics and treatment of SDB in children and youth from 2 to 18 years of age (Fig. 1). The scientific data from 362 publications were presented in a condensed form of "seven steps", very useful in diagnosing and treatment planning (1). The authors underline the limited number of reliable evidence about SDB: prospective studies, randomized double-blinded studies with placebo. The presented evidence was categorized depending on their quality according to the classification of the American Academy of Neurology (ANN) into classes I - IV. Previously, in 2012, the guidelines of the American Academy of Pediatrics on obstructive sleep apnea syndrome (OSAS) in children with tonsillar hypertrophy and/or obesity were published (2, 3) and they were a valuable diagnostic and therapeutic compendium. The European guidelines discussed in this article result from the progress of knowledge in recent years, they cover the subject broadly, consider rare and difficult cases and present the spectrum of potential therapeutic actions. The aim of the guidelines is a better recognition of SDB, a systematization of diagnosis and treatment at every stage of medical care, including the causes of this disorder and its complications.

Prevalence and clinical characteristics of obstructive- and central-dominant sleep apnea in candidates of catheter ablation for atrial fibrillation in Japan.

INTRODUCTION: We aimed to study the prevalence and types of sleep apnea (SA) as well as their clinical characteristics in atrial fibrillation (AF) ablation candidates in Japan. METHODS: Before catheter ablation, 197 consecutive AF patients (age: 60 ±â€¯9 years, body mass index; 25.0 ±â€¯3.0) were evaluated with portable polygraphy. We compared the clinical characteristics, according to the severity of SA as well as its types, as defined by the presence of obstruction and the mixed vs. central apnea indices. RESULTS: The mean apnea-hypopnea index (AHI) was 17.7 ±â€¯11.9, with 135 AF patients having an AHI ≥10 (68.5%). Patients with an AHI ≥10 had a significantly higher body mass index, plasma brain natriuretic peptide (BNP) level, prevalence of hypertension, and larger left atrial size. Among patients with an AHI ≥10, the incidence of obstructive-dominant SA was 60.9% and that of central-dominant SA was 7.6%. The prevalence of hypertension was significantly higher in obstructive-dominant SA patients (obstructive vs. central: 48.3% vs. 20.0%, P = 0.038). The obstructive apnea index correlated with plasma BNP level and age, but the central and mixed apnea indices did not. CONCLUSIONS: The prevalence of SA was common in AF ablation candidates, even without an obesity epidemic, and the SA type was predominantly obstructive. Portable polygraphy was useful for detecting undiagnosed SA patients in AF ablation candidates.

More than meets the eye: infant presenting with hypoxic ischaemic encephalopathy.

We report a newborn infant who presented with poor Apgar scores and umbilical artery acidosis leading to the diagnosis of hypoxic ischaemic encephalopathy. During the course of the infant's hospitalisation, subsequent workup revealed an underlying genetic cause that masqueraded as hypoxic ischaemic encephalopathy.

Sleep-disordered breathing and its management in children with achondroplasia.

Sleep-disordered breathing is a common feature in children with achondroplasia. The aim of our study was to review the poly(somno)graphic (P(S)G) findings and consequent treatments in children with achondroplasia followed in the national reference center for skeletal dysplasia. A retrospective review of the clinical charts and P(S)G of 43 consecutive children (mean age 3.9 ± 3.5 years) with achondroplasia seen over a period of 2 years was performed. Twenty four (59%) children had obstructive sleep apnea (OSA). Thirteen children had an obstructive apnea-hypopnea index (OAHI) < 5/hr, four had an OAHI between 5 and 10/hr, and seven had an OAHI ≥ 10/hr. Ten of the 15 children who had previous upper airway surgery still had an abnormal P(S)G. All the patients with an AHI ≥ 10/hr were under 7 years of age and none had a prior tonsillectomy. The children who underwent adeno-tonsillectomy, coupled in most cases with turbinectomy, were significantly older (mean age 7.5 ± 3.5 vs. 3.5 ± 1.7 years old, P = 0.015) and had significantly better P(S)G results than those who underwent only adeno-turbinectomy. No correlation was observed between the mean AHI value at the baseline P(S)G and the type of academic course (standard, supported or specialized). In conclusion, OSA is common in children with achondroplasia. The observation of a reduced prevalence of OSA after (adeno-)tonsillectomy is in favor of this type of surgery when possible.

Alternative methods of lung isolation in cases of pediatric bilateral thoracoscopic surgery.

We compare airway management and lung isolation methods in two pediatric cases of congenital central hypoventilation syndrome undergoing bilateral throacoscopic phrenic-nerve-stimulator surgery. One child received lung isolation using a 7Fr bronchial blocker in conjunction with a 6.0 cuffed endotracheal tube; and the second received a technique of endobronchial intubation using a 3.5 microcuffed tube via the tracheostomy stoma in conjunction with 5.0 cuffed endotracheal intubation; a technique previously undescribed in pediatric patients.

Phrenic Nerve Stimulation: Technology and Clinical Applications.

Phrenic nerve stimulation is a technique used to reanimate the diaphragm of patients with central nervous system etiologies of respiratory insufficiency. Current clinical indications include congenital central hypoventilation syndrome, spinal cord injury above C4, brain stem injury, and idiopathic severe sleep apnea. Presurgical evaluation ensures proper patient selection by validating the intact circuit from the phrenic nerve through alveolar oxygenation. The procedure involves placing leads around the phrenic nerves bilaterally and attaching these leads to radio receivers in a subcutaneous pocket. The rate and amplitude of the current is adjusted via an external radio transmitter. After implantation, each patient progresses through a conditioning phase that strengthens the diaphragm and progressively provides independence from the mechanical ventilator. Studies indicate that patients and families experience an improved quality of life and are satisfied with the results. Phrenic nerve stimulation provides a safe and effective means for reanimating the diaphragm for certain patients with respiratory insufficiency, providing independence from mechanical ventilation.

Effect of Adenotonsillectomy on Central and Obstructive Sleep Apnea in Children with Down Syndrome.

OBJECTIVES: To determine and quantify changes in both central and obstructive sleep apnea in patients with Down syndrome (DS) after adenotonsillectomy (AT). STUDY DESIGN: Case series with chart review. SETTING: Tertiary care children's hospital. SUBJECTS AND METHODS: The records of all patients with DS who underwent AT for sleep-disordered breathing between November 2008 and December 2014 were examined. In total, 113 patients were identified, and 36 of these patients had pre- and postoperative polysomnograms (PSGs) that were analyzed for obstructive and central components. Wilcoxon signed-rank test, paired t test, and McNemar test were used to examine pre- and postoperative PSG differences. Logistic regression and multivariate analysis of variance of patient characteristics (between subjects) and PSG results (within subjects) were conducted. RESULTS: The mean (SD) patient age was 5.5 (4.0) years (range, 0.9-15 years); 50.0% were male. After AT, significant reductions were identified in both obstructive apnea-hypopnea index (AHI) (P < .001) and overall AHI (P < .001). Among the 15 patients with severe obstructive sleep apnea, 86.7% experienced a significant AHI reduction to moderate or mild disease (P < .001). In addition, of the 15 patients with central sleep apnea (central apnea index [CAI] >1), 66.7% had resolution of central sleep apnea postoperatively (P = .004). There was also a significant interaction identified between CAI reduction, preoperative CO2 retention, and adenoid size, F(2, 20) = 6.87, P = .05. CONCLUSION: Children with DS who underwent AT demonstrated significant reductions in both obstructive and central apneic indices on PSG. A significant number of patients with central sleep apnea demonstrated resolution postoperatively. Additional analysis demonstrated a significant interaction between CO2 retention, adenoid size, and postoperative CAI reduction.

Efficacy of tracheostomy for central alveolar hypoventilation syndrome caused by lateral medullary infarction.

Central alveolar hypoventilation syndrome (CAHS) is a rare and potentially fatal condition. However, respiratory care for patients with CAHS caused by lateral medullary infarction (CAHS-LMI) remains an important unsolved problem. We describe 2 patients with CAHS-LMI and review the case reports for 17 previously described patients. Patient 1 was a 78-year-old man who was referred to our hospital because of dizziness. After admission, Wallenberg syndrome developed. Magnetic resonance imaging showed left LMI. He had hypercapnia and respiratory acidosis the next afternoon and temporarily received mechanical ventilation. A tracheotomy was performed on the 12th hospital day, and the patient was weaned from the ventilator on the 18th hospital day. Patient 2 was 72-year-old man who was referred to our hospital because of dizziness and gait disturbance. Wallenberg syndrome was diagnosed after admission, and magnetic resonance imaging showed right LMI. His consciousness deteriorated, and hypercapnia developed on the ninth hospital day. The patient received ventilatory support, and a tracheotomy was performed on the 12th hospital day. He was weaned from the ventilator by the 16th hospital day. Consistent with our findings, most previously reported cases of CAHS-LMI were initially associated with mild symptoms, which subsequently worsened. Five of the 19 patients (26.3%) died within 1 month after onset, and 7 patients (36.8%) died within 1 year. Tracheotomy was performed in 12 patients, 2 of whom died 1 month after onset (16.7%); another patient died of chronic renal failure after 2 years. Tracheotomy seemed to be an effective procedure in patients with CAHS-LMI. We speculate that tracheotomy assists alveolar ventilation by reducing dead space ventilation. Closure of the tracheotomy should, therefore, be avoided in patients with CAHS-LMI, even if respiratory status is good.

Elimination of central sleep apnea by cardiac valve replacement: a continuous follow-up study in patients with rheumatic valvular heart disease.

BACKGROUND: Recent studies have suggested that cardiac surgery may affect sleep-disordered breathing (SDB) in chronic heart failure patients. However, the dynamic changes in sleep apnea and heart function after cardiac surgery and the mechanisms responsible for these changes remain unknown. METHODS: Patients with rheumatic valvular heart disease (RVHD) and SDB were enrolled and followed up at three, six and 12 months after cardiac valve replacement (CVR). Baseline and follow-up clinical data consisting of NYHA classification, 6min walk distance (6-MWD), medications, echocardiography, electrocardiography, chest X-ray, arterial blood gas, lung-to-finger circulation time (LFCT), and sleep data were collected and evaluated. RESULTS: Twenty-four central sleep apnea (CSA) patients and 15 obstructive sleep apnea (OSA) patients completed three follow-up assessments. Comparison of the baseline parameters between OSA patients and CSA patients showed that CSA patients had a worse baseline cardiac function assessed by higher NYHA class, shorter 6-MWD, larger left atrial diameter, longer LFCT, and enhanced chemosensitivity (higher pH and lower arterial carbon dioxide tension (PaCO2)). A continuous significant elevation in 6-MWD and left ventricular ejection fraction and decrease in NYHA class, plasma BNP, and left atrial diameter were found in both CSA and OSA patients. When comparing CSA and OSA patients, the CSA indices were remarkably reduced at month 3 post CVR and sustained throughout the trial, whereas there were no significant decreases in OSA index and hypopnea index. pH values and LFCT were markedly decreased and PaCO2 markedly increased in patients with CSA at the end of the third months following CVR. These changes were sustained until the end of the trial. CONCLUSIONS: CSA patients with RVHD had a worse baseline cardiac function, enhanced chemosensitivity and disordered hemodynamic as compared with OSA patients with RVHD. CSA were eliminated after CVR; however, there were no changes in OSA. The elimination of CSA, post CVR, is associated with the combined efficacies of improvement of cardiac function, normalized chemosensitivity, and stabilized hemodynamic.