Impact of parenteral prostanoids in pulmonary arterial hypertension. the relevance of timing

Parenteral prostanoids are being recommended in pulmonary arterial hypertension (PAH) treatment, but the prognostic relevance of delayed treatment initiation is still debated. This study assessed the impact of the timing of prostacyclin treatment initiation on reducing PVR and achieving a low-risk profile in PAH patients. The study enrolled 151 patients who started on parenteral prostanoids with different treatment strategies. All patients underwent right heart catheterization, clinical evaluation, and risk assessments at baseline and after 1-year follow-up. Patients with an upfront strategy including parenteral prostanoid plus one oral drug had -5.3 +/- 6.2 WU (-50 +/- 19%) reduction in PVR, patients with an upfront strategy including parenteral prostanoid plus double oral drug had -12.8 +/- 5.9 WU (-68 +/- 17%) reduction in PVR, while patients with an add-on strategy including parenteral prostanoid after oral drugs had -3.9 +/- 3.5 WU (-23 +/- 19%) reduction in PVR. An upfront strategy including parenteral prostanoids was independently associated with an increased likelihood of achieving the greater reduction of PVR compared with an add-on strategy. Additionally, the greater the severity of PH at the time of diagnosis, in terms of PVR and RV reverse remodeling, the higher the probability of treatment failure. An upfront strategy including a parenteral prostanoid is associated with the highest likelihood of achieving a low-risk profile and a greater reduction of PVR compared with parenteral prostanoid as an add-on to oral treatment.