title: High prevalence of recurrent nocturnal desaturations in systemic AL amyloidosis: a cross-sectional pilot study.
abstract: OBJECTIVE
  Cardiac involvement and/or macroglossia with soft tissue deposits are risk factors for central sleep apnoea (CSA) and obstructive sleep apnoea (OSA), and common features of systemic AL amyloidosis. Little data exist on the occurrence of sleep-disordered breathing (SDB) or recurrent nocturnal hypoxia in amyloidosis, which this study sought to investigate.
  
  
  METHODS
  A total of 72 consecutive patients with systemic amyloidosis (mean age 69 years and mean BMI 25) were evaluated for occurrence of SDB, by overnight continuous pulse oximetry, and completed Epworth Sleepiness Score (ESS) and STOPBANG questionnaires. Patients included: AL cardiac (AL-C), AL macroglossia (AL-M), AL both (AL-CM) and transthyretin (ATTR).
  
  
  RESULTS
  Mean overnight oxygen saturations were 93% (SD ± 2, 95% CI 87-96) with abnormal oximetry (4% oxygen desaturation index (ODI) >5/hour): AC-C 84%, AL-M 57%, AL-CM 62% and ATTR 47%. NYHA class directly correlated with a higher 4% ODI, NYHA class I vs 3, (p = 0.01). Two-thirds of patients had STOPBANG scores >3 and abnormally high ESS scores (>10) were seen in up to 30% of patients.
  
  
  CONCLUSIONS
  Recurrent nocturnal hypoxaemia, suggestive of sleep-disordered breathing, is frequent in systemic AL amyloidosis. The higher incidence in cardiac amyloidosis highlights CSA and recurrent hypoxia as possible mechanisms for morbidity/mortality in these cases. A detailed polysomnography study is planned to clarify and further investigate these findings.
authors.affiliation: National Amyloidosis Centre, Division of Medicine, Royal Free Hospital Campus, University College of London Medical School, London, UK.
authors.forename: Shameem
authors.initials: S
authors.lastname: Mahmood
authors.affiliation: Respiratory Support and Sleep Centre, Nottingham University Hospitals, Nottingham, UK.
authors.forename: Milind
authors.initials: M
authors.lastname: Sovani
authors.affiliation: Respiratory Support and Sleep Centre, Nottingham University Hospitals, Nottingham, UK.
authors.forename: Peter
authors.initials: P
authors.lastname: Smith
authors.affiliation: Respiratory Support and Sleep Centre, Nottingham University Hospitals, Nottingham, UK.
authors.forename: Leena
authors.initials: L
authors.lastname: George
authors.affiliation: National Amyloidosis Centre, Division of Medicine, Royal Free Hospital Campus, University College of London Medical School, London, UK.
authors.forename: Christina C
authors.initials: CC
authors.lastname: Quarta
authors.affiliation: National Amyloidosis Centre, Division of Medicine, Royal Free Hospital Campus, University College of London Medical School, London, UK.
authors.forename: Sajitha
authors.initials: S
authors.lastname: Sachchithanantham
authors.affiliation: National Amyloidosis Centre, Division of Medicine, Royal Free Hospital Campus, University College of London Medical School, London, UK.
authors.forename: Marianna
authors.initials: M
authors.lastname: Fontana
authors.affiliation: National Amyloidosis Centre, Division of Medicine, Royal Free Hospital Campus, University College of London Medical School, London, UK.
authors.forename: Carol J
authors.initials: CJ
authors.lastname: Whelan
authors.affiliation: National Amyloidosis Centre, Division of Medicine, Royal Free Hospital Campus, University College of London Medical School, London, UK.
authors.forename: Helen J
authors.initials: HJ
authors.lastname: Lachmann
authors.affiliation: National Amyloidosis Centre, Division of Medicine, Royal Free Hospital Campus, University College of London Medical School, London, UK.
authors.forename: Julian D
authors.initials: JD
authors.lastname: Gillmore
authors.affiliation: National Amyloidosis Centre, Division of Medicine, Royal Free Hospital Campus, University College of London Medical School, London, UK.
authors.forename: Philip N
authors.initials: PN
authors.lastname: Hawkins
authors.affiliation: National Amyloidosis Centre, Division of Medicine, Royal Free Hospital Campus, University College of London Medical School, London, UK. Electronic address: a.wechalekar@ucl.ac.uk.
authors.forename: Ashutosh D
authors.initials: AD
authors.lastname: Wechalekar
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D003430:Cross-Sectional Studies; D005260:Female; D006801:Humans; D000860:Hypoxia / Q000453:epidemiology / Q000209:etiology; D000075363:Immunoglobulin Light-chain Amyloidosis / Q000150:complications*; D008297:Male; D008875:Middle Aged; D010865:Pilot Projects; D015995:Prevalence; D012891:Sleep Apnea Syndromes / Q000453:epidemiology* / Q000209:etiology*
keywords: 4% oxygen desaturation index (ODI); Macroglossia and cardiac AL amyloidosis; Nocturnal oxygen desaturations; Prognostic utility of oxygen desaturations