title: Cardiopulmonary exercise testing to detect chronic thromboembolic pulmonary hypertension in patients with normal echocardiography.
abstract: BACKGROUND
  Chronic thromboembolic pulmonary hypertension (CTEPH) is a serious complication of pulmonary embolism (PE). Taking into account the reported incidence of CTEPH after acute PE, the number of patients with undiagnosed CTEPH may be high.
  
  
  OBJECTIVE
  We aimed to determine if cardiopulmonary exercise testing (CPET) could serve as complementary tool in the diagnosis of CTEPH and can detect CTEPH in patients with normal echocardiography.
  
  
  METHODS
  At diagnosis, we analyzed the data of CPET parameters in 42 patients with proven CTEPH and 51 controls, and evaluated the performance of two scores.
  
  
  RESULTS
  VE/VCO2 slope, EQO2, EQCO2, P(A-a)O2, end-tidal partial pressure of CO2 at anaerobic threshold (PETCO2) and capillary to end-tidal carbon dioxide gradient [P(c-ET)CO2] were significantly different between patients with CTEPH and controls (p < 0.001). P(c-ET)CO2 was the single parameter with the highest sensitivity (85.7%) and specificity (88.2%). A score combining VE/VCO2 slope, P(A-a)O2, P(c-ET)CO2, PETCO2 [4-parameter-CPET (4-P-CPET) score] reached a sensitivity of 83.3% and a specificity of 92.2% after cross-validation. In 42 patients with CTEPH, echocardiography identified PH in 29 patients (69%), but it was normal in 13 patients (31%). All patients with normal or unmeasurable right ventricular systolic pressure had a pathological CPET. Twelve of the 13 patients (92%) were detected by both CPET scores.
  
  
  CONCLUSIONS
  CPET is a useful noninvasive diagnostic tool for the detection of CTEPH in patients with suspected PH but normal echocardiography. The 4-P-CPET score provides a high sensitivity with the highest specificity.
authors.affiliation: Department of Internal Medicine, Medical Mission Hospital, Academic Teaching Hospital, Julius Maximilian University of Würzburg, Würzburg, Germany.
authors.forename: Matthias
authors.initials: M
authors.lastname: Held
authors.forename: Maria
authors.initials: M
authors.lastname: Grün
authors.forename: Regina
authors.initials: R
authors.lastname: Holl
authors.forename: Gudrun
authors.initials: G
authors.lastname: Hübner
authors.forename: Ralf
authors.initials: R
authors.lastname: Kaiser
authors.forename: Sabine
authors.initials: S
authors.lastname: Karl
authors.forename: Martin
authors.initials: M
authors.lastname: Kolb
authors.forename: Hans Joachim
authors.initials: HJ
authors.lastname: Schäfers
authors.forename: Heinrike
authors.initials: H
authors.lastname: Wilkens
authors.forename: Berthold
authors.initials: B
authors.lastname: Jany
mesh_terms: D000368:Aged; D019296:Capnography; D016022:Case-Control Studies; D002908:Chronic Disease; D015331:Cohort Studies; D004452:Echocardiography; D005080:Exercise Test; D005260:Female; D006801:Humans; D006976:Hypertension, Pulmonary / Q000175:diagnosis* / Q000000981:diagnostic imaging / Q000209:etiology; D008297:Male; D008875:Middle Aged; D011655:Pulmonary Embolism / Q000150:complications / Q000175:diagnosis* / Q000000981:diagnostic imaging; D011659:Pulmonary Gas Exchange; D012123:Pulmonary Ventilation; D012189:Retrospective Studies; D012680:Sensitivity and Specificity