Effect of cardiac transplantation on Cheyne-Stokes respiration occurring during sleep

Exertional and nocturnal periodic breathing after successful cardiac transplantation. A case report

We present a case report of a heart failure patient who underwent cardiopulmonary exercise testing and sleep screening 12 months before and after heart transplantation (HTx). Severe Cheyne-Stokes respiration (CSR) with central sleep apnoea (CSA) was identified either before and after HTx, while periodic breathing during exercise vanished. We suggest that optimization of hemodynamics and medical therapy (low dose of diuretic) did not withdraw the central mechanisms underlying the diathesis for CSR-CSA. While periodic breathing during exercise reversal may support a closer link with an exertional central hemodynamic. This observation indirectly neglects the possible unifying mechanistic background of CSR and periodic breathing, during exercise, in this setting.

Non-Mask-based Therapies for Central Sleep Apnea in Patients with Heart Failure

Central sleep apnea is common in heart failure and contributes to morbidity and mortality. Symptoms are often similar to those associated with heart failure and a high index of suspicion is needed. Testing is typically done in the sleep laboratory, but home testing equipment can distinguish between central and obstructive events. Treatments are limited. Mask-based therapies have been the primary treatment. Oxygen has some data but lacks long-term studies. Neurostimulation of the phrenic nerve is a new technology that has demonstrated improvement. Coordination of care between sleep specialists and cardiologists is important as the field of central sleep apnea continues to develop.

Congestive Heart Failure and Central Sleep Apnea

Congestive heart failure (CHF) is among the most common causes of admission to hospitals in the United States, especially in those over age 65. Few data exist regarding the prevalence CHF of Cheyne-Stokes respiration (CSR) owing to congestive heart failure in the intensive care unit (ICU). Nevertheless, CSR is expected to be highly prevalent among those with CHF. Treatment should focus on the underlying mechanisms by which CHF increases loop gain and promotes unstable breathing. Few data are available to determine prevalence of CSR in the ICU, or how CSR might affect clinical management and weaning from mechanical ventilation.

Congestive heart failure and central sleep apnea

Congestive heart failure (CHF) is among the most common causes of admission to hospitals in the United States, especially in those over age 65. Few data exist regarding the prevalence CHF of Cheyne-Stokes respiration (CSR) owing to congestive heart failure in the intensive care unit (ICU). Nevertheless, CSR is expected to be highly prevalent among those with CHF. Treatment should focus on the underlying mechanisms by which CHF increases loop gain and promotes unstable breathing. Few data are available to determine prevalence of CSR in the ICU, or how CSR might affect clinical management and weaning from mechanical ventilation.

Mechanisms and clinical consequences of untreated central sleep apnea in heart failure

Central sleep apnea (CSA) is a highly prevalent, though often unrecognized, comorbidity in patients with heart failure (HF). Data from HF population studies suggest that it may present in 30% to 50% of HF patients. CSA is recognized as an important contributor to the progression of HF and to HF-related morbidity and mortality. Over the past 2 decades, an expanding body of research has begun to shed light on the pathophysiologic mechanisms of CSA. Armed with this growing knowledge base, the sleep, respiratory, and cardiovascular research communities have been working to identify ways to treat CSA in HF with the ultimate goal of improving patient quality of life and clinical outcomes. In this paper, we examine the current state of knowledge about the mechanisms of CSA in HF and review emerging therapies for this disorder.

A novel therapeutic approach for the treatment of central sleep apnea: The remedē® system

Central sleep apnea (CSA) occurs primarily in cardiovascular patients and is associated with high morbidity and mortality. The disorder often is unrecognized due to the overlap of symptoms with those of the underlying cardiac disease. CSA can be easily diagnosed with a sleep study. Following optimization of all co-morbidities, the therapeutic approach available currently focuses on mask-based therapies which suffer from poor patient adherence. A new therapy, the remedē® System, has been developed; it utilizes a transvenous, fully implantable system providing phrenic nerve stimulation intended to restore a more normal breathing pattern. The therapy demonstrated promising results based on an initial chronic study and a randomized trial is underway to further evaluate safety and efficacy of this novel system in patients with CSA.

The Relationship between Nocturnal Hypoxemia and Left Ventricular Ejection Fraction in Congestive Heart Failure Patients

Congestive heart failure (CHF) is a major cause of mortality and morbidity. Among patients with heart failure, sleep disordered breathing (SDB) is a common problem. Current evidence suggests that SDB, particularly central SDB, is more prevalent in patients with CHF than in the general population, but it is underdiagnosed as SDB symptoms that are less prevalent in CHF. The main aims of this study were to determine the relationship between nocturnal hypoxemia and left ventricular ejection fraction in patients with chronic heart failure. By means of echocardiography, 108 patients with left ventricular ejection fraction ≤45% were divided into mild, moderate, and severe CHF. Hypoxemia was recorded overnight in the hospital and was measured by portable pulse oximetry. In the 108 patients with CHF, 44 (40.7%) were severe, 17 (15.7%) moderate, and 47 (43.6%) mild CHF. 95 (88%) of patients with CHF had abnormal patterns of nocturnal hypoxemia suggestive of Cheyne-Stokes respiration. Ejection fraction correlated negatively with dip frequency. There was no correlation between nocturnal hypoxemia with BMI and snoring. This study confirms strong associations between sleep apnea and heart disease in patients with CHF. Overnight oximetry is a useful screening test for Cheyne-Stokes respiration in patients with known heart failure.

Sleep-disordered breathing in acute decompensated heart failure

Sleep-disordered breathing (SDB), including obstructive sleep apnea (OSA) and central sleep apnea (CSA), is highly prevalent and frequently unrecognized in patients with chronic heart failure (HF). Untreated SDB may worsen acute decompensation of HF and delay recovery by increasing vascular inflammation and oxidative stress, impeding control of the blood pressure, and promoting arrhythmias. Untreated OSA doubles the risk for developing HF, and patients with HF who develop OSA are thought to have a worse prognosis than patients with HF alone. Similar to the findings in the general population, treatment of OSA appears to reduce cardiovascular morbidity and mortality in HF. The presence of CSA is associated with increased mortality in HF patients. Efficacious suppression of central sleep apnea with continuous positive airway pressure therapy may reduce mortality in HF.

Central sleep apnea: implications for congestive heart failure

Congestive heart failure (HF), an exceedingly common and costly disease, is frequently seen in association with central sleep apnea (CSA), which often manifests as a periodic breathing rhythm referred to as Cheyne-Stokes respiration. CSA has historically been considered to be a marker of heart disease, since improvement in cardiac status is often associated with the attenuation of CSA. However, this mirroring of HF and CSA may suggest bidirectional importance to their relationship. In fact, observational data suggest that CSA, associated with repetitive oxyhemoglobin desaturations and surges in sympathetic neural activity, may be of pathophysiologic significance in HF outcomes. In light of the disappointing results from the first large trial assessing therapy with continuous positive airway pressure in patients with CSA and HF, further large-scale interventional trials will be needed to assess the role, if any, of CSA treatment on the outcomes of patients with HF. This review will discuss epidemiologic, pathophysiologic, diagnostic, and therapeutic considerations of CSA in the setting of HF.

Symptoms of dysautonomia, sleep disturbance, and abnormal cognition in pediatric heart failure

Sleep disorders, autonomic dysfunction, and abnormal cognition are important comorbidities in adult patients with heart failure and are associated with disease progression, morbidity, and mortality. The clinical incidence of these conditions is unknown in children with heart failure. We sought to determine the incidence of symptoms that may be attributable to autonomic dysfunction among children with dilated cardiomyopathy and heart failure. We performed a retrospective chart review of patients with dilated cardiomyopathy seen at our institution between 1999 and 2005. We reviewed charts for symptoms of dysautonomia, sleep problems, or abnormal cognition. From the records of 204 pediatric patients, we identified 69 patients aged 7-18 years with severe dilated cardiomyopathy. Of these, 55 (80%) had symptoms attributable to dysautonomia, 20 (29%) had evidence of sleep disturbance, and 3 (4%) had abnormal cognition. Dysautonomia and sleep disturbances are prevalent in children with heart failure, congruent with studies of adult patients. Based on our data, it is not possible to draw conclusions about any cognitive deficits in this population. Because relatively few subjects' charts explored symptoms of sleep disturbance, we speculate that sleep symptoms may be underappreciated.

Reversal of Nocturnal Periodic Breathing in Primary Pulmonary Hypertension After Lung Transplantation

Nocturnal periodic breathing (PB) closely resembling Cheyne-Stokes respiration in congestive heart failure has been reported to occur in end-stage primary pulmonary hypertension (PPH). We herein describe the clinical course of a 56-year-old female patient with PPH and severe hypoxemia, hypocapnia, and right ventricular compromise in whom sleep-disordered breathing (SDB) resolved after successful double-lung transplantation. This case illustrates the crucial roles of blood gas alterations and hemodynamic impairment in the emergence of PB in PPH, and is in favor of a genuine association between advanced right heart failure and the development of SDB.

The Effect of Successful Heart Transplant Treatment of Heart Failure on Central Sleep Apnea *

STUDY OBJECTIVE

Central sleep apnea (CSA) associated with Cheyne-Stokes respiration in patients with congestive heart failure (CHF) is thought to be an acquired pattern of respiratory control instability related, at least in part, to elevated sympathetic nervous system activity. The effect of restoring heart function to normal with heart transplantation in patients with CHF and CSA has only been reported within weeks of the transplant and with varying results. The purpose of the study was to evaluate the impact of successful heart transplant on sympathetic nervous system activity and CSA severity in patients with CHF.

DESIGN

Controlled prospective trial.

SETTING

University hospital.

PATIENTS

Twenty-two patients with CHF (13 patients with CSA, and 9 patients with no sleep-disordered breathing [SDB]).

INTERVENTIONS AND MEASUREMENTS

Polysomnography, left ventricular ejection fraction (LVEF), and overnight urinary norepinephrine excretion (UNE) were measured before and > 6 months after successful heart transplantation.

RESULTS

In the CSA group, there was a fall in apnea-hypopnea index (AHI) [mean +/- SD, 28 +/- 15 to 7 +/- 6/h; p < 0.001] and UNE (48.1 +/- 30.9 to 6.1 +/- 4.8 nmol/mmol creatinine, p < 0.001) associated with normalization of LVEF (19.2 +/- 9.3% to 53.7 +/- 6.1%, p < 0.001) at 13.2 +/- 8.3 months following heart transplantation. Of the CSA group following transplantation, seven patients had no SDB (AHI < 5/h), three patients had persistent CSA (AHI, 12.3 +/- 0.9/h) and four patients acquired obstructive sleep apnea (OSA) [AHI, 11.2 +/- 7.4/h]. In comparison, none of the control group acquired CSA or OSA after transplantation.

CONCLUSIONS

We conclude that CSA may persist despite normalization of heart function and sympathetic nerve activity.

Sleep apnea in heart transplant recipients: type, symptoms, risk factors, and response to nasal continuous positive airway pressure

BACKGROUND

We determined the type, symptoms, and risk factors for sleep apnea in heart transplant recipients and the response to nasal continuous positive airway pressure.

METHODS

A retrospective study on heart transplant recipients with sleep apnea was conducted in a tertiary care medical center with follow-up telephone interviews. Between February 1988 and August 1998, 147 patients underwent orthotopic heart transplantation at our institution. Seventeen patients (11.6%) who were suspected of having sleep apnea underwent polysomnography at a mean interval of 17.5 months after transplantation.

RESULTS

All were diagnosed with sleep apnea: 13 had obstructive sleep apnea and 4 had mixed sleep apnea. Mean age at polysomnography was 50.8 years (range, 24-67 years). The patients presented with snoring (100%), excessive daytime somnolence (65%), witnessed apneas (53%), and morning fatigue (53%). Sixteen (94%) had a mean weight gain of 10.4 kg after transplantation, and 1 patient lost 14.6 kg. In the 11 patients with obstructive sleep apnea who underwent nasal continuous positive airway pressure titration, significant improvements occurred in the apnea-hypopnea index (decreased from 37.6 to 10.4; p = 0.01) and mean arousal index (decreased from 44.5 to 19.4; p = 0.01). Only 2 of the 8 patients with sleep apnea for whom nasal continuous positive airway pressure was recommended continued to use it at the time of telephone follow-up.

CONCLUSIONS

Sleep apnea, especially obstructive sleep apnea, occurs frequently in heart transplant recipients. Obstructive sleep apnea appears to present in the typical manner, and although a positive response to nasal continuous positive airway pressure can be documented by polysomnography, long-term use of nasal continuous positive airway pressure may be low.

Association between hemodynamic impairment and Cheyne-Stokes respiration and periodic breathing in chronic stable congestive heart failure secondary to ischemic or idiopathic dilated cardiomyopathy

Irregular breathing occurs frequently in patients with congestive heart failure (CHF) both during daytime and nighttime. Many factors are involved in the genesis of these breathing abnormalities, but the role of the hemodynamic impairment remains controversial. This study investigated the relation between worsening ventricular function and the frequency of respiratory disorders in patients with mild to severe CHF. One hundred fifty patients with CHF (mean age 53 +/- 8 years, left ventricular (LV) ejection fraction 26 +/- 7, in New York Heart Association [NYHA] classes II to IV, and who underwent stable therapy for > or =2 weeks) were studied. Analysis of instantaneous lung volume signal and arterial oxygen saturation during awake daytime revealed a normal respiratory pattern in 63 patients, whereas 87 had a persistent alteration of breathing, with a typical Cheyne-Stokes respiration (CSR) in 42 and periodic breathing (PB [oscillation of tidal volumes without apnea]) in 45 patients. Patients with PB and CSR showed a more pronounced hemodynamic impairment with a significantly reduced cardiac index, an increased pulmonary arterial wedge pressure, and a longer lung-to-ear circulation time (LECT) compared with patients with normal respiratory patterns. In a logistic regression model that included all of the variables significantly associated with breathing disorders, cardiac index and LECT emerged as the major determinants of CSR. In those patients with LECT > or =30 seconds (upper quartile) and cardiac index < or =1.9 L/min/m2 (lower quartiles), the incidence of CSR was significantly higher (69%) than in patients with lower LECT and higher cardiac index (14%, p <0.001). In conclusion, abnormalities of breathing activity during daytime are significantly associated with a prolonged circulation time and a more severe impairment of systolic and diastolic LV indexes.

Reversal of central sleep apnea with oxygen

OBJECTIVE

To examine the effect of oxygen on apneas and sleep quality in patients with frequent central apneas during sleep.

DESIGN/SUBJECTS

Prospective intervention study of 20 consecutive patients with predominant central apnea identified from 570 patients referred for suspected sleep apnea syndrome. Sixteen patients had congestive heart failure and seven of them had a previous stroke. Three of the remaining four patients without heart failure had experienced a previous stroke, and one was being treated with morphine.

SETTING

The Department of Pulmonary Medicine at Umeå (Sweden) University Hospital.

INTERVENTIONS

The patients were investigated for one night receiving nasal oxygen and one night without it.

MEASUREMENTS

Overnight polysomnography with transcutaneous PCO2 and arterial blood gases.

RESULTS

Central apneas occurred during Cheyne-Stokes respiration in 18 of 20 patients and two patients had idiopathic central apneas. Without oxygen, the median number of all central apneas and hypopneas was 33.5 (range, 8.0 to 52.0) per hour of sleep. These episodes decreased to 5.0 (range, 0.0 to 31.0)(p < 0.01) during oxygen therapy. In 17 of 20 patients, the frequency of central apneas was reduced by more than 50%. Central apneas were reduced by oxygen irrespective of the presence or absence of heart failure or Cheyne-Stokes respiration. The arousal frequency was reduced during oxygen treatment. Daytime sleepiness, difficulty falling asleep, snoring, and self-scored awakenings were reduced in seven patients who were given nocturnal oxygen at home. Obstructive and mixed apneas were unaffected by oxygen.

CONCLUSIONS

Oxygen effectively reduces central sleep apnea in eucapnic patients.