title: High occurrence of hypoxemic sleep respiratory disorders in precapillary pulmonary hypertension and mechanisms.
abstract: BACKGROUND
  The occurrence and mechanisms of nocturnal hypoxemia in precapillary pulmonary hypertension (PH) are not clearly defined.
  
  
  METHODS
  In an observational, prospective, and transversal design, we studied 46 clinically stable patients with PH and a BMI < 35 kg/m(2), an FEV(1) > 60% predicted, and idiopathic pulmonary arterial hypertension (n = 29) or chronic thromboembolic pulmonary hypertension (n = 17). They underwent nocturnal polysomnography with transcutaneous capnography.
  
  
  RESULTS
  Most patients (69.6%) had New York Heart Association functional class II disease. Mean pulmonary artery pressure was 44 ± 13 mm Hg, and the cardiac index was 3.2 ± 0.6 L/min/m(2). Duration of sleep time spent with oxygen saturation as measured by pulse oximetry <90% was 48.9% ± 35.9%, and 38 of 46 patients (82.6%) had nocturnal hypoxemia. Mean apnea-hypopnea index was 24.9 ± 22.1/h, and 41 patients (89%) had sleep apnea. The major mechanism of nocturnal hypoxemia was a ventilation/perfusion mismatch alone or associated with obstructive apneic events. Multivariate logistic regression identified both FEV(25%-75%) (OR, 0.9519; 95% CI, 0.9089-0.9968; P = .036) and mean pulmonary artery pressure (OR, 1.1068; 95% CI, 1.0062-1.2175; P = .037) as significant predictors of nocturnal hypoxemia. Clinical symptoms were not predictive of nocturnal hypoxemia.
  
  
  CONCLUSIONS
  The occurrence of nocturnal hypoxemia is high in PH and should be screened for systematically. Further studies are needed to determine the impact of nocturnal hypoxemia on the outcome of patients with PH.
  
  
  BACKGROUND
  ClinicalTrials.gov; No.: NCT01371669; URL: www.clinicaltrials.gov
authors.affiliation: Faculté de Médecine, Université Paris-Sud, Le Kremlin-Bicêtre; Assistance Publique-Hôpitaux de Paris, Unité de Médecine du Sommeil, Hôpital Antoine-Béclère, Clamart; Faculté de Pharmacie, Université Paris-Sud, EA3544, Châtenay-Malabry, France.
authors.forename: Fadia Nicolas
authors.initials: FN
authors.lastname: Jilwan
authors.affiliation: Faculté de Médecine, Université Paris-Sud, Le Kremlin-Bicêtre; Assistance Publique-Hôpitaux de Paris, Unité de Médecine du Sommeil, Hôpital Antoine-Béclère, Clamart; Faculté de Pharmacie, Université Paris-Sud, EA3544, Châtenay-Malabry, France.
authors.forename: Pierre
authors.initials: P
authors.lastname: Escourrou
authors.affiliation: Faculté de Médecine, Université Paris-Sud, Le Kremlin-Bicêtre; Assistance Publique-Hôpitaux de Paris, Unité de Médecine du Sommeil, Hôpital Antoine-Béclère, Clamart; Institut National de la Santé et de la Recherche Médicale U999 Hypertension Artérielle Pulmonaire: Physiopathologie et Innovation Thérapeutique, Le Plessis-Robinson.
authors.forename: Gilles
authors.initials: G
authors.lastname: Garcia
authors.affiliation: Faculté de Médecine, Université Paris-Sud, Le Kremlin-Bicêtre; Assistance Publique-Hôpitaux de Paris, Service de Pneumologie et Réanimation Respiratoire, Hôpital Antoine-Béclère, Clamart; Institut National de la Santé et de la Recherche Médicale U999 Hypertension Artérielle Pulmonaire: Physiopathologie et Innovation Thérapeutique, Le Plessis-Robinson.
authors.forename: Xavier
authors.initials: X
authors.lastname: Jaïs
authors.affiliation: Faculté de Médecine, Université Paris-Sud, Le Kremlin-Bicêtre; Assistance Publique-Hôpitaux de Paris, Service de Pneumologie et Réanimation Respiratoire, Hôpital Antoine-Béclère, Clamart; Institut National de la Santé et de la Recherche Médicale U999 Hypertension Artérielle Pulmonaire: Physiopathologie et Innovation Thérapeutique, Le Plessis-Robinson.
authors.forename: Marc
authors.initials: M
authors.lastname: Humbert
authors.affiliation: Faculté de Médecine, Université Paris-Sud, Le Kremlin-Bicêtre; Assistance Publique-Hôpitaux de Paris, Unité de Médecine du Sommeil, Hôpital Antoine-Béclère, Clamart. Electronic address: gabriel.roisman@abc.aphp.fr.
authors.forename: Gabriel
authors.initials: G
authors.lastname: Roisman
mesh_terms: D000328:Adult; D000367:Age Factors; D000368:Aged; D001785:Blood Gas Monitoring, Transcutaneous; D065627:Familial Primary Pulmonary Hypertension; D005260:Female; D006801:Humans; D006976:Hypertension, Pulmonary / Q000150:complications / Q000503:physiopathology*; D000860:Hypoxia / Q000150:complications / Q000503:physiopathology*; D016015:Logistic Models; D008297:Male; D008875:Middle Aged; D017286:Polysomnography; D011446:Prospective Studies; D012891:Sleep Apnea Syndromes / Q000150:complications / Q000503:physiopathology*; D012893:Sleep Wake Disorders / Q000150:complications / Q000503:physiopathology*; D014692:Ventilation-Perfusion Ratio