title: Pulmonary hypertension in obesity-hypoventilation syndrome.
abstract: BACKGROUND
  Pulmonary hypertension (PH) is considered a clinically important feature of Obesity-Hypoventilation Syndrome (OHS). We aimed to determine prevalence, characteristics and severity of PH including associations with clinical outcomes after established non-invasive positive pressure ventilation (NPPV).
  
  
  METHODS
  In a prospective cross-sectional study, clinically stable OHS-patients (NPPV duration ≥ 3 months) were consecutively assessed using echocardiography, serum markers and right-heart catheterization (RHC). NPPV use was quantified via ventilator counters. Blood gases, lung function, Epworth-Sleepiness Scale (ESS), sleep-quality, WHO-functional class (WHO-FC), 6-min walk distance, and health-related quality of life (HRQL) via Severe Respiratory Insufficiency (SRI) questionnaire were assessed.
  
  
  RESULTS
  Of 177 patients considered, 64 fulfilled inclusion criteria. Among these, 21 patients (10 female/11 male; BMI 45 [40; 53] kg/m(2), PaCO2 39.6 [37.8; 45.5] mmHg (median [quartiles])) gave consent for RHC. Four patients (19%) had normal mean pulmonary artery pressure (mPAP < 20 mmHg), 8 (38.1%) mPAP 20-24 mmHg and 9 (42.9%) manifest PH (mPAP ≥ 25 mmHg), 3 of them with combined pre- and/or postcapillary PH. mPAP was negatively correlated to NPPV use, vital capacity and lung diffusing capacity (p < 0.01 each), and positively to BMI (p < 0.05). NPPV use and vital capacity independently predicted mPAP. In patients with PH, ESS, WHO-FC, and some SRI-items were worse (p < 0.05 each) compared to patients without PH. Multivariate analyses revealed mPAP as the only independent predictor of the SRI-physical functioning domain.
  
  
  CONCLUSIONS
  Mild to moderate PH is frequent in patients with OHS despite NPPV, mPAP being inversely related to NPPV adherence. PH is associated with impairments in daytime-sleepiness, WHO-FC, HRQL and physical functioning.
authors.affiliation: Center for Pneumology, Donaustauf Hospital, Ludwigstraße 68, D-93093 Donaustauf, Germany.
authors.forename: Christoph A
authors.initials: CA
authors.lastname: Kauppert
authors.forename: Iris
authors.initials: I
authors.lastname: Dvorak
authors.forename: Florian
authors.initials: F
authors.lastname: Kollert
authors.forename: Frank
authors.initials: F
authors.lastname: Heinemann
authors.forename: Rudolf A
authors.initials: RA
authors.lastname: Jörres
authors.forename: Michael
authors.initials: M
authors.lastname: Pfeifer
authors.forename: Stephan
authors.initials: S
authors.lastname: Budweiser
mesh_terms: D000368:Aged; D003430:Cross-Sectional Studies; D005260:Female; D006333:Heart Failure / Q000150:complications / Q000503:physiopathology; D006439:Hemodynamics / Q000502:physiology; D006801:Humans; D006976:Hypertension, Pulmonary / Q000209:etiology* / Q000503:physiopathology / Q000628:therapy; D008297:Male; D010845:Obesity Hypoventilation Syndrome / Q000150:complications* / Q000503:physiopathology / Q000628:therapy; D011175:Positive-Pressure Respiration / Q000379:methods; D011446:Prospective Studies; D011788:Quality of Life; D012131:Respiratory Insufficiency / Q000150:complications / Q000503:physiopathology; D011795:Surveys and Questionnaires; D016896:Treatment Outcome
keywords: Obesity hypoventilation; Pulmonary hypertension; Respiratory failure; Right heart failure