Longterm oxygen therapy in precapillary pulmonary hypertension - the SOPHA study.

<bold>Background and objective:</bold> Current guidelines recommend oxygen (O2) supplementation in patients with pulmonary hypertension (PH), despite scarce data on long-term O2 therapy (LTOT). The aim of this study was to investigate the effect of LTOT in patients with precapillary PH on exercise capacity and clinical parameters. <bold>Methods:</bold> In this prospective, randomized, controlled trial, patients with precapillary PH under stable targeted therapy and O2 desaturations at rest and/or during exercise were randomized to receive LTOT (≥16 h/day) or no O2 (control group) for 12 weeks. The control group was offered LTOT after 12 weeks (secondary intervention). The primary endpoint change of 6-minute walking distance (6MWD) from baseline to 12 weeks was hierarchically tested: 1) pre-post primary and secondary intervention 2) intervention vs control group. Secondary endpoints included changes in clinical parameters. <bold>Results:</bold> A total of 20 patients (10 vs. 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). LTOT significantly improved 6MWD by 42.2±34.20 m (p=0.003) from baseline to week 12. 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 between-group differences in other clinical parameters were found. Two patients died during the study, one due to SARS-CoV2 pneumonia in the O2 arm, one due to renal insufficiency leading to right heart failure in the control group. <bold>Conclusion:</bold> LTOT was well tolerated and significantly improved the primary endpoint 6MWD.