Nitric Oxide Stroke Volume Index as a New Hemodynamic Prognostic Parameter for Patients with Pulmonary Arterial Hypertension

The aim of the study was to determine the prognostic value of hemodynamic parameters measured during initial diagnostic right heart catheterization (RHC) in standard conditions and using a nitric oxide reversibility test. A retrospective observational study of 62 patients with pulmonary arterial hypertension (PAH) was performed. Clinical, biochemical, echocardiographic, and hemodynamic data obtained at the time of the PAH diagnosis were precisely analyzed. Patients were followed for five years. Death or lung transplantation was considered as a primary endpoint. The mean follow-up period was 1090 ± 703 days and the median age was 46.84 years. In the studied group, 25 patients survived, 36 patients died, and one underwent a lung transplantation. From all the examined parameters, only stroke volume index during reversibility test with iNO (SVI((NO test))) (HR = 0.910; 95% confidence interval 0.878–0.944; p < 0.001) and initial arterial oxygen saturation (SaO(2)) (HR = 0.910; 95% confidence interval 0.843–0.982; p = 0.015) have been established as independent predictors of death or lung transplantation in the five-year follow–up. An SVI((NO test)) value above 39.86 mL/m(2) was associated with 100% five-year survival rate (AUC = 0.956; 95% confidence interval 0.899–1.000; p < 0.001; specificity/sensitivity: 100/84%). The results of the analysis suggest that the SVI((NO test)) measured during the initial diagnostic RHC could be a very valuable prognostic factor in the PAH patients.