title: Lung function and gas exchange in Eisenmenger syndrome and their impact on exercise capacity and survival.
abstract: BACKGROUND
  Eisenmenger physiology may contribute to abnormal pulmonary mechanics and gas exchange and thus impaired functional capacity. We explored the relationship between lung function and gas exchange parameters with exercise capacity and survival.
  
  
  METHODS
  Stable adult patients with Eisenmenger syndrome (N=32) were prospectively studied using spirometry, lung volumes, diffusion capacity, and blood gas analysis, as well as same day measurement of 6-minute walk distance and cardiopulmonary maximal treadmill exercise. Patients were followed prospectively to determine survival (7.4 ± 0.5 years). Abnormalities were identified and appropriate comparisons were made between affected and unaffected individuals between respiratory mechanics, exercise function, and survival.
  
  
  RESULTS
  Obstruction (FEV1/FVC ratio <0.70) was found in 13 patients (41%), who were older but not otherwise different. Restriction was uncommon. Diffusion transfer coefficient, which was <80% in half the patients, correlated with exercise duration (r=0.542, P=0.005), and was worse in non-survivors (N=6). Nearly all patients had a compensated respiratory alkalosis (PaCO2 32 ± 4.4 mm Hg). PaCO2 was less reduced in older patients (r=0.438, P=0.022), and correlated independently with exercise duration (R=-0.463, P=0.03), yet PaO2, not PaCO2, was associated with survival.
  
  
  CONCLUSIONS
  Eisenmenger patients show evidence of obstructive lung disease, diffusion abnormalities, and hypocapnia; likely from hyperventilation. Understanding expected lung mechanics and gas exchange may facilitate more appropriate clinical management.
authors: Adult Congenital Heart Disease Program, Division of Cardiovascular Medicine, Oregon Health and Science University, Portland, OR, United States. Electronic address: brobergc@ohsu.edu.
authors: Craig S
authors: CS
authors: Broberg
authors: Adult Congenital Heart Disease Program, Division of Cardiovascular Medicine, Oregon Health and Science University, Portland, OR, United States.
authors: Ryan C
authors: RC
authors: Van Woerkom
authors: Respiratory Muscle Laboratory, Royal Brompton Hospital and Harefield NHS Foundation Trust, National Heart and Lung Institute, Imperial College, London, UK.
authors: Elizabeth
authors: E
authors: Swallow
authors: NIHR Cardiovascular Biomedical Research Unit, Royal Brompton and Harefield NHS Foundation Trust, National Heart and Lung Institute, Imperial College London, UK.
authors: Kostas
authors: K
authors: Dimopoulos
authors: NIHR Cardiovascular Biomedical Research Unit, Royal Brompton and Harefield NHS Foundation Trust, National Heart and Lung Institute, Imperial College London, UK.
authors: Gerhard-Paul
authors: GP
authors: Diller
authors: Division of Pulmonology, Oregon Health and Science University, Portland, OR, United States.
authors: Gopal
authors: G
authors: Allada
authors: NIHR Cardiovascular Biomedical Research Unit, Royal Brompton and Harefield NHS Foundation Trust, National Heart and Lung Institute, Imperial College London, UK.
authors: Michael A
authors: MA
authors: Gatzoulis
mesh_terms: D000328:Adult; D015331:Cohort Studies; D004541:Eisenmenger Complex / Q000175:diagnosis* / Q000401:mortality / Q000503:physiopathology; D015444:Exercise / Q000502:physiology; D005080:Exercise Test / Q000379:methods; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D008168:Lung / Q000502:physiology*; D008173:Lung Diseases, Obstructive / Q000175:diagnosis* / Q000401:mortality / Q000503:physiopathology; D008297:Male; D008875:Middle Aged; D011446:Prospective Studies; D011659:Pulmonary Gas Exchange / Q000502:physiology*; D015656:Respiratory Mechanics / Q000502:physiology; D015996:Survival Rate / Q000639:trends
keywords: Blood gas; Cyanosis; Eisenmenger; Hypocapnia; Lung function; Pulmonary arterial hypertension