Prognostic role of superoxide dismutase 3 concentration in pulmonary arterial plasma on pulmonary vascular resistance and all-cause death in patients with left heart failure

Objective To examine whether the superoxide Dismutase 3 (SOD3)concentration in pulmonary artery plasma contributes to the increase in pulmonary vascular resistance (PVR) and its prognostic role. Methods Between January 2014 and August 2016, 154 consecutive patients with pulmonary hypertension secondary to left heart failure (PH-LHF) treated with right heart catheterization were prospectively followed up. According to the data of right heart catheterization, patients were divided into 3 groups: normal group ( mPAP 15 mmHg, PVR≤3 WUs); reactive group (mPAP ≥25 mmHg, PAWP>15 mmHg, PVR>3 WUs). Pulmonary arterial (PA) blood samples were used to calculate NT-proBNP, norepinephrine(NE), cyclic adenosine monophosphoate, cyclic guanosine monophosphate and SOD3. The primary composite endpoint was the incidence of cardiac readmission or all-course death. Cox proportional hazards ratios were used to estimate the associations between clinical variables and mortality. Results 154 patients were enrolled, including 102 males (66.2%) and 52 females (33.7%), with an average follow-up of 1.9 years(ys)(from 0.5 ys to 3.2 ys). There was a statistically significant difference in uric acid among the normal group (n=40), the passive group (n=43) and the reactive group (n=71)(P<0.001). The results of 6 minute walking distance were significantly different in the three groups(P<0.001). At the end of the follow-up, there were 9 all-cause deaths in the reactive group, with 6 in the passive group and 0 in the normal group(P=0.034). Multiple linear regression analysis revealed that only the levels of NT-proBNP and SOD3 in pulmonary plasma were independent predictors of PVR(P=0.011, 0.003 respectively). Multivariate Cox regression analysis revealed that only PVR and the level of SOD3 in pulmonary plasma were independent predictors of death in patients with PH-LHF. Conclusions The pulmonary arterial plasma concentration of SOD3 in patients with PH-LHF decreased significantly and negatively correlated with pulmonary vascular resistance. The concentration of SOD3 is the independent predictor of all-cause death in patients with PH-LHF. Key words: Hypertension, pulmonary; Ventricular dysfunction, left; Hemodynamics; Superoxide dismutase