• Neil R Ward, Vitor Roldao, Martin R Cowie, Stuart D Rosen, Theresa A McDonagh, Anita K Simonds, and Mary J Morrell.
• Clinical and Academic Department of Sleep and Breathing, National Heart and Lung Institute, Royal Brompton Hospital and Imperial College, London, United Kingdom. neil.ward@nhs.net
• Sleep. 2013 Sep 1;36(9):1341-8.

Study ObjectivesTo evaluate the effect of respiratory scoring criteria on diagnosis and classification of sleep disordered breathing (SDB) in chronic heart failure (CHF).DesignCross-sectional observational study.SettingHeart failure and general cardiology clinics at two London hospitals.Patients Or ParticipantsOne hundred eighty stable patients with CHF and a median age of 69.6 y, 86% male.InterventionsSDB was diagnosed by polysomnography. The apnea-hypopnea index (AHI) was initially scored using a conservative hypopnea definition of a ≥ 50% decrease in nasal airflow with a ≥ 4% oxygen desaturation. The AHI was rescored with hypopnea defined according to the American Academy of Sleep Medicine (AASM) alternative scoring rule, requiring an associated ≥ 3% oxygen desaturation or arousal. SDB was defined as AHI ≥ 15/h. Diagnosis and classification of SDB as obstructive sleep apnea (OSA) or central sleep apnea (CSA) with each rule were compared. The effect of mixed apneas on classification of SDB as CSA or OSA was also investigated.Measurements And ResultsMedian AHI increased from 9.3/h to 13.8/h (median difference 4.6/h) when the AASM alternative rule was used to score hypopneas. SDB prevalence increased from 29% to 46% with the alternative scoring rule (P < 0.001). Classification of SDB as OSA or CSA was not significantly altered by hypopnea scoring rules or the categorization of mixed apneas.ConclusionHypopnea scoring rules can significantly influence the apnea-hypopnea index and diagnosis of sleep disordered breathing in chronic heart failure but do not alter the classification as obstructive sleep apnea or central sleep apnea. Standardization of hypopnea scoring rules is important to ensure consistency in diagnosis of sleep disordered breathing in chronic heart failure patients.

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