Cardiopulmonary exercise testing to detect chronic thromboembolic pulmonary hypertension in patients with normal echocardiography

Respiration. 2014;87(5):379-87. doi: 10.1159/000358565. Epub 2014 Apr 11.


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.

Objectives: 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.

Conclusion: 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.

MeSH terms

  • Aged
  • Capnography
  • Case-Control Studies
  • Chronic Disease
  • Cohort Studies
  • Echocardiography
  • Exercise Test*
  • Female
  • Humans
  • Hypertension, Pulmonary / diagnosis*
  • Hypertension, Pulmonary / diagnostic imaging
  • Hypertension, Pulmonary / etiology
  • Male
  • Middle Aged
  • Pulmonary Embolism / complications
  • Pulmonary Embolism / diagnosis*
  • Pulmonary Embolism / diagnostic imaging
  • Pulmonary Gas Exchange
  • Pulmonary Ventilation
  • Retrospective Studies
  • Sensitivity and Specificity