Acute Hemodynamic Responses to Supplemental Oxygen and Their Prognostic Implications in Pulmonary Hypertension

Background: Pulmonary hypertension (PH) of various causes leads to a poor prognosis. Pulmonary vasoreactivity testing during right heart catheterization (RHC) has prognostic and therapeutic consequences. Objective: To characterize the acute hemodynamic response to short-term oxygen supplementation (SHOT) in adult PH patients and its impact on prognosis. Methods: After a stable baseline period, 104 patients with PH [pulmonary arterial hypertension (PAH; n = 56), chronic thromboembolic (PH; n = 22) or respiratory diseases (PH; n = 26)], who were mainly therapy-naïve (86.5%) (mean p O 2 64.5 ± 1.2 mm Hg), received a standardized SHOT during RHC and hemodynamic response was assessed for its prognostic potential. Results: SHOT significantly reduced heart rate (HR: 78.9 ± 1.5 to 74 ± 1.5 beats/min), cardiac output (4 ± 0.1 to 3.8 ± 0.1 l/min), pulmonary arterial pressure (46.4 ± 1.3 to 42.3 ± 1.3 mm Hg) and pulmonary vascular resistance (10.1 ± 0.5 to 9.6 ± 0.5 Wood units; all p < 0.001) compared to baseline. The magnitude of this effect varied between the different PH groups. During a median follow-up of 25.1 months (range: 0.2-73.3 months), HR