1Thoraxklinik - Heidelberg gGmbH Pneumologie und Beatmungsmedizin / Zentrum für Pulmonale Hypertonie Heidelberg, Deutschland; 2UniversitätsSpital Zürich Klinik für Pneumologie Zürich, Schweiz
Background: Current guidelines recommend oxygen (O2) supplementation in patients with pulmonary hypertension (PH), despite scarce data on long-term O2 administration (LTOT). The aim of this study was to investigate the effect of LTOT in patients with precapillary PH on exercise capacity, clinical parameters and hemodynamics.
Methods: In this prospective, randomized, controlled trial, patients with precapillary PH under stable targeted therapy, experiencing O2 desaturations at rest and/or during exercise were randomly assigned to receive LTOT (≥16 h/day) or standard of care (SoC) for 12 weeks. To patients receiving SoC, LTOT was offered after 12 weeks (secondary intervention group). The primary endpoint was analysed in a hierarchical testing strategy of 1) the change of the distance walked in 6 minutes (6MWD) after 12 weeks of treatment in the primary and secondary intervention group 2) the comparison of changes in the 6MWD baseline to 12 weeks in the intervention vs control group. Secondary endpoints included changes in clinical, laboratory and functional parameters, quality of life and hemodynamics.
Results: A total of 20 patients (O2 n=10 vs. SoC n=10) were randomized (women n=14, age 67±11.4 years, mean pulmonary arterial pressure 39.7±12.5 mmHg, 70% WHO functional class III). After LTOT treatment a significant improvement in 6MWD of 42.2±34.20 m (p=0.003) at week 12 was measured compared to baseline (Figure 1). The intervention group significantly improved in 6MWD (38.9±33.87 m) compared to the control group (-12.3±21.83 m, p=0.015). No consistent differences between groups in other clinical parameters were found. Two patients died during the study, one patient due to SARS-CoV2 pneumonia in the O2 arm and one due to right heart failure in the SoC arm. These events were not associated with the study medication.
Conclusion: Long-term O2 therapy was well tolerated and resulted in a significant improvement of the primary endpoint 6MWD. The effect of LTOT should be further investigated in larger controlled-trials.