Clinical heterogeneity of patients with complex sleep apnea syndrome

Division of Pulmonary and Critical Care Medicine, NorthShore University HealthSystem, 2650 Ridge Avenue, Evanston, IL, USA, .
Sleep And Breathing (Impact Factor: 2.48). 02/2013; 17(4). DOI: 10.1007/s11325-013-0825-4
Source: PubMed


The definition of complex sleep apnea (CompSAS) encompasses patients with obstructive sleep apnea (OSA) who develop central apnea activity upon restitution of airway patency. Presence of arterial hypertension (HTN), coronary artery disease (CAD) and heart failure (HF) have been proposed as risk factors for CompSAS among OSA patients. Using our database of patients with CompSAS, we examined the prevalence of these risk factors and defined other clinical characteristics of patients with CompSAS.

Through retrospective search of the database, we examined the medical and clinical characteristics of consecutive patients diagnosed with CompSAS between 11/1/2006 and 6/30/2011 at NorthShore University HealthSystem.

One hundred and fifty patients with CompSAS were identified. Among patients included in the study, 97 (64.7 %) had at least one risk factor for CompSAS, while 53 (35.3 %) did not have any of them. Prevalence of low left ventricular ejection fraction and hypocapnia were low. Therapeutic interventions consisted of several positive airway pressure therapies, mainly adaptive servo ventilation. A hundred and ten patients (73.3 %) complied with recommended therapy and improved clinically.

Although most patients with CompSAS have cardiac comorbidities, about one third of patients do not have any risk factors of CompSAS prior to sleep testing. Further research on factors involved in development of CompSAS will allow for better tailoring of therapy to pathophysiology involved in an individual case.

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Available from: Tomasz J. Kuzniar,
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    ABSTRACT: Complex sleep apnoea syndrome (CompSAS) is a type of central apnoea characterised by the development or persistence of central apnoeas or hypopnoeas during application of continuous positive airway pressure (CPAP; central apnoea index ≥5 events·h-1). These patients present with predominantly obstructive apnoeas during diagnostic sleep studies. No clinical characteristics have been identified which can distinguish them from patients with a normal response during CPAP titration. Probably, this pattern is provoked by the application of high CPAP pressures in obstructive sleep apnoea syndrome patients with enhanced chemoreceptor sensitivity, or in patients with pronounced sleep fragmentation. Negative feedback is sent to the respiratory centre, via the Hering-Breuer reflex, which can lead to central apnoea. However, these explanations remain hypothetical at present. In a broader perspective, any occurrence of significant central apnoea activity during attempts to restore airway patency could be classified as CompSAS. Treatment modalities consist of prevention on the one hand (avoidance of high pressures and permissive flow limitation), and advanced ventilation techniques (adaptive servo ventilation) on the other hand.
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