P43
J. Müller1, M. Lichtblau1, S. Saxer1, L. R. Calendo1, A. Carta1, S. Schneider1, K. . Bloch1, S. Ulrich1 (1Zürich)
To evaluate the effects of breathing oxygen-enriched air (oxygen) on exercise performance in patients with pulmonary hypertension due to heart failure with preserved ejection fraction (PH-HFpEF).
10 patients with PH-HFpEF (5 women, age 60±9 years, mPAP 37±14 mmHg, PAWP 18±2 mmHg, PVR 3±3 WU, resting SpO2 98±2 %) performed two cycle incremental exercise tests (IET) and two constant work-rate exercise test (CWRET) at 75 % maximal work-rate (Wmax) achieved with ambient air, each with ambient air (FiO2 0.21) and oxygen (FiO2 0.50) in a randomized, single-blinded, cross-over design. The main outcomes were the change in Wmax (IET) and cycling-time (CWRET) with oxygen versus air. Blood gases at rest and end-exercise, dyspnea by Borg 10 scale at end-exercise and continuous SpO2, minute ventilation (VE), carbon dioxide output (VCO2), cerebral and quadriceps muscle tissue oxygenation (CTO and MTO) were measured.
With oxygen vs. air, Wmax increased from 94±36 to 99±36 W, mean difference (95% CI) 5.4 (0.9 to 9.8) W, p=0.025 in IET and cycling-time from 532±203 to 680±76 seconds (s), +148 (31.8 to 264) s, p=0.018. At end-exercise with oxygen, Borg dyspnea score, VE/VCO2 were lower whereas PaO2 and end-tidal CO2 were higher, other parameters were unchanged.
Patients with PH-HFpEF not revealing resting hypoxemia, significantly improved their exercise performance with breathing oxygen-enriched air along with less dyspnea sensation, a better blood oxygenation and an enhanced ventilatory efficiency.
PH-HFpEF patients may benefit from oxygen therapy during exercise training.