Abstract 2109: Preserved Right Ventricular Function in Eisenmenger Syndrome Compared to Idiopathic Pulmonary Hypertension: A Possible Clue to Improved Survival
Background: Pulmonary hypertension (PH) leads to right ventricular (RV) failure and eventual death. Patients (pts) with idiopathic PH (IPH) follow a rapid decline from diagnosis to worsening heart failure as compared to those with Eisenmenger syndrome (ES) who may survive decades despite severe PH. Etiologies for improved survival in ES have been proposed but not investigated. In other cardiovascular disease states, ventricular function predicts survival. Therefore, we tested the hypothesis that right ventricular function could better distinguish ES from IPH pts compared to hemodynamic or exercise data.
Methods: Aged-matched pts with IPH and ES who underwent cardiac magnetic resonance imaging (CMR), cardiac catheterization and 6 minute walk test were identified. CMR data included RV and LV EDVI, ESVI, and EF. CMR, hemodynamic and 6 minute walk test (6MWT) data were compared between the 2 groups by t-test and Pearson correlation.
Results: We compared 20 IPH with 20 ES pts (mean age 46 ± 18.7 vs. 36.7 ± 17.2 yrs., p = NS). The RVEF in the ES group was significantly greater compared to the IPH pts. (43.3 ± 0.14 vs. 26.7 ± 0.12, p < 0.001). Interestingly, the LV size was greater (EDVI, p < 0.05) and ESVI (p< 0.05) in the ES compare to IPH group, possibly related to long standing left to right shunt, however LVEF was not statistically different. There was a positive correlation between RVEDVI and LVEDVI, which was stronger in the IPH patients (IPH; r2 0.48 p < 0.005; ES; r2 0.16, p < 0.05). This data suggests an intraventricular dependence may occur with worsening RV enlargement particularly for IPH pts. Traditional predictors of outcomes for PH pts including PA pressure, pulmonary vascular resistance indexed and 6MWT distance were not statistically different between the 2 groups.
Conclusion: This is the first study to date demonstrating improved RVEF in aged- matched ES vs. IPH pts. Traditional markers of heart failure and prognosis including exercise capacity and hemodynamics were comparable and did not separate ES from IPH pts. Only RVEF was significantly different and may explain improved long- term survival in ES pts. Future studies directed toward the utilization of CMR may provide benefit in the management of both ES and IPH pts