title: Pulmonary vascular limitation to exercise and survival in idiopathic pulmonary fibrosis.
abstract: OBJECTIVE
  Pulmonary hypertension is frequently observed in advanced idiopathic pulmonary fibrosis (IPF) and is associated with poor prognosis. Cardiopulmonary exercise testing (CPET) can be used to detect less advanced pulmonary vascular impairment, and therefore may be of prognostic use. We studied the predictive value of non-invasive exercise parameters that were associated with elevated systolic pulmonary artery pressure (sPAP) for survival in IPF patients.
  
  
  METHODS
  From our interstitial lung disease database, we reviewed records of consecutive patients with IPF in whom CPET and echocardiography were performed within 2 weeks (n = 38).
  
  
  RESULTS
  Eleven patients (29%) had increased sPAP (≥40 mm Hg). From all non-invasive CPET parameters, only the ventilatory equivalent for CO2 (V'E /V'CO2 ) at anaerobic threshold differed significantly between patients with and without sPAP ≥ 40 mm Hg. The receiver-operator characteristic curve for V'E /V'CO2 resulted in areas under the curve of 0.77 (95% CI: 0.569-0.970; P = 0.026), with a cut-off value for predicting sPAP ≥ 40 mm Hg of >45.0. Patients with V'E /V'CO2  > 45.0 had significantly worse survival compared with patients with V'E /V'CO2  ≤ 45.0 (P = 0.001). In contrast, sPAP did not predict survival.
  
  
  CONCLUSIONS
  V'E /V'CO2 , the only CPET parameter associated with elevated sPAP, appears a potentially useful non-invasive marker for early detection of pulmonary vascular impairment, and therefore may be of use for a more accurate prognostic assessment in IPF patients.
authors.affiliation: Department of Respiratory Medicine, Onze Lieve Vrouwe Gasthuis, Amsterdam, the Netherlands.|Department of Respiratory Medicine, Academic Medical Centre, University of Amsterdam, Amsterdam, the Netherlands.
authors.forename: Mart N
authors.initials: MN
authors.lastname: van der Plas
authors.affiliation: Department of Respiratory Medicine, Onze Lieve Vrouwe Gasthuis, Amsterdam, the Netherlands.
authors.forename: Coen
authors.initials: C
authors.lastname: van Kan
authors.affiliation: Department of Respiratory Medicine, Onze Lieve Vrouwe Gasthuis, Amsterdam, the Netherlands.|Department of Respiratory Medicine, Academic Medical Centre, University of Amsterdam, Amsterdam, the Netherlands.
authors.forename: Judith
authors.initials: J
authors.lastname: Blumenthal
authors.affiliation: Department of Respiratory Medicine, Academic Medical Centre, University of Amsterdam, Amsterdam, the Netherlands.
authors.forename: Henk M
authors.initials: HM
authors.lastname: Jansen
authors.affiliation: Interstitial Lung Disease Unit, Royal Brompton Hospital, London, UK.
authors.forename: Athol U
authors.initials: AU
authors.lastname: Wells
authors.affiliation: Department of Respiratory Medicine, Onze Lieve Vrouwe Gasthuis, Amsterdam, the Netherlands.|Department of Respiratory Medicine, Academic Medical Centre, University of Amsterdam, Amsterdam, the Netherlands.
authors.forename: Paul
authors.initials: P
authors.lastname: Bresser
mesh_terms: D000328:Adult; D000368:Aged; D005080:Exercise Test / Q000379:methods*; D017079:Exercise Tolerance / Q000502:physiology*; D005260:Female; D006801:Humans; D054990:Idiopathic Pulmonary Fibrosis / Q000401:mortality / Q000503:physiopathology*; D008297:Male; D008875:Middle Aged; D009426:Netherlands / Q000453:epidemiology; D011652:Pulmonary Circulation / Q000502:physiology*; D015996:Survival Rate / Q000639:trends; D014655:Vascular Resistance / Q000502:physiology*
keywords: cardiopulmonary exercise test; exercise; idiopathic pulmonary fibrosis; pulmonary function test; pulmonary hypertension