Effect of a daytrip to altitude (2500 m) on exercise performance in pulmonary hypertension – randomized cross-over trial

Question addressed by the study To investigate exercise performance and hypoxia-related health-effects in patients with pulmonary hypertension (PH) during a high-altitude sojourn. Patients and Methods In a randomized crossover trial in stable (same therapy for >4 weeks) patients with pulmonary arterial or chronic thromboembolic PH (PAH/CTEPH) with resting PaO2 ≥7.3kPa, we compared symptom-limited constant work-rate exercise test (CWRET) cycling time during a daytrip to 2500 m versus 470 m. Further outcomes were symptoms, oxygenation and echocardiography. For safety, patients with sustained hypoxemia at altitude (SpO2 30 min or 15 min) received oxygen therapy. (ClinicalTrials.gov: NCT03637153) Results 28 PAH/CTEPH-patients (15/13), 13 females, mean±sd age 63±15y were included. After >3 h at 2500 m versus 470 m, CWRET-time was reduced to 17±11 versus 24±9 min (mean-difference 95%CI) −6(-10 to −3) corresponding to −27.6% (-41.1 to −14.1) p Conclusion This randomized cross-over study showed that the majority of PH-patients tolerate a daytrip to 2500 m well. At high versus low altitude, the mean exercise time was reduced, albeit with a high inter-individual variability, and pulmonary artery pressure at rest and during exercise increased, but pressure-flow slope and dyspnoea were unchanged.