Cardiopulmonary exercise testing in patients with precapillary pulmonary hypertension with an unfavorable prognosis

Aim. To compare clinical and hemodynamic parameters with survival of incident patients with idiopathic pulmonary arterial hypertension (IPAH) and chronic thromboembolic pulmonary hypertension (CTEPH) with a prognostically unfavorable pattern of cardiopulmonary exercise testing (CPET) parameters. Material and methods . The study included 48 incident cases with a verified diagnosis of IPAH (n=18) and CTEPH (n=30). All patients were examined in accordance with the European Society of Cardiology and the European Respiratory Society guidelines (2015). The inclusion criterion was the ventilatory equivalent for carbon dioxide (CO 2 ) according to the CPET (VE/VCO 2 ) >44, indicating an unfavorable prognosis for patients. Results. VE/VCO 2 in the examined patients with IPAH and CTEPH averaged 70,6±0,8 and did not differ in the study groups. Hemodynamic parameters of patients with IPAH and CTEPH also indicated a high risk of adverse events as follows: cardiac index — 1,9±0,1 and 1,8±0,1 l/min/m 2 , respectively (p=0,3). Peak oxygen consumption, anaerobic threshold level, oxygen delivery to work performed were reduced in both groups. However, patients with IPAH did not have a decrease in dead space ventilation and desaturation severity during exercise was greater than in patients with CTEPH. Patients with CTEPH had better survival compared to patients with IPAH: 1 year — 89 vs 83%, 3 years — 84 vs 65%, 5 years — 73 vs 35%, 7 years — 55 vs 36%. Conclusion. Among patients with IPAH and CTEPH who have an unfavorable prognosis, patients with IPAH demonstrate a more pronounced decrease in cardiovascular and respiratory reserves, which negatively affects patient survival. CPET may be a valuable non-invasive method for death risk stratification in patients with IPAH and CTEPH.