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

Abstract

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<smlcap>O</smlcap>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 <72 beats/min in response to SHOT was associated with a better prognosis in patients with PH due to chronic thromboembolism to the lung and PH from chronic lung disease. Conclusions: SHOT leads to characteristic hemodynamic responses across different forms of PH. The preserved capability to acutely respond to SHOT with HR reduction is of prognostic significance in patients with non PAH PH.