Abstract 16728: Elevated Levels of Interleukin 6 Predicts Survival in Patients With Pulmonary Hypertension
Background: There is substantial evidence supporting a role of Interleukin 6 (IL-6) in development of pulmonary hypertension (PH). However limited information exists on the significance of elevated IL-6 levels or their potential as biomarkers. We hypothesized that elevated IL-6 levels in pts with PH have a significant impact on prognosis, hemodynamics and functional capacity.
Materials and methods: We assessed serum IL-6 levels in 89 patients with established diagnosis and treatment of PH and prospectively followed them from 2011- 2013. In addition to basic demographics, the following data were gathered: hemodynamic measurements from the right heart catheterization, 6 minute walk distance (6MWD), oxygen requirements and NYHA classification at the time of blood sampling. Patients were classified according to Dana Point 2008 classification for PH. Survival status was gathered at May 31, 2013 and survival time was calculated individually for each patient from sampling of cytokine to censoring, death or lung transplantation.
Results: Serum IL-6 levels were elevated in 70 out of 89 patients (78.6%) with a mean level of 16 pg/ml compared to 1.9 pg/ml in group with normal IL-6 (normal range 0-3 pg/ml). There was no statistically significant difference in hemodynamics, 6 MWD, oxygen requirements and NYHA class between patients with normal and elevated IL-6 levels. Mean 6MWD was (250 vs 277 meters, P=0.8) and mean PVR was (6.5 vs 7.8 Wood unit; p=0.32) in pts with normal and elevated IL-6 levels respectively. At a mean follow up period of 14 months, the incidence of death/lung transplantation was 5% (1 death, survival 95%) compared to 16% (10 deaths, 1 lung transplant, survival 84%) in group with normal and elevated IL-6 levels respectively. In group with elevated IL-6 levels, the subjects who died had a mean survival of 9 months and mean IL-6 level of 25 pg/ml.
Conclusion: IL-6 is elevated in significant no. of pts (78%) with PH. We found no correlation of elevated IL-6 levels with worsening hemodynamics, functional capacity, oxygen requirements or NYHA classification. Elevated IL-6 level is associated with overall worse prognosis and may prove to be a better prognostic marker than 6MWD and hemodynamics, but a longer follow up period is required to draw definite conclusion.
- © 2013 by American Heart Association, Inc.