Does arterial oxygenation during exercise add prognostic value in pulmonary arterial hypertension?

The 6-min walking distance (6MWD) is often used to assess prognosis in pulmonary arterial hypertension (PAH) patients. Whether or not changes in arterial oxygen saturation (SpOAmbispective study that includes 137 patients with PAH: 38 idiopathic/heritable (i/h PAH), 42 with connective tissue disease (CTD-PAH), 34 with porto-pulmonary hypertension (PoPH), 21 with HIV-associated PAH and 2 with pulmonary venous occlusive disease (PVOD). Patients were characterized and, treated according to international recommendations, and were followed-up for 5 years. To integrate SpO(1) during follow-up, 40 patients died (29.2%); (2) results confirmed the prognostic value of the 6MWD (AUC 0.913 [IQR 0.868-0.958]; p 0.0001), original DDR (AUC 0.923 [0.881-0.966]; p 0.001), New DDR (AUC 0.917 [0.872-0.961], p 0.001), and DSP (AUC 0.914 [0.869-0.959], p 0.001); and, (3) neither the original or new DDR or DSP added significant prognostic value to 6MWD in these patients.Consideration of three different composite indices of arterial oxygenation changes during exercise does not add prognostic value to that of the 6MWD in patients with PAH.