Abstract 17964: Right Ventricular Reverse Remodeling during Long-Term Continuous-Flow Left Ventricular Assist Device Support in Patients with Dilated Cardiomyopathy

Introduction: Although right ventricle (RV) failure as well as left ventricle (LV) failure can be of major concern in the treatment for severe heart failure, in clinical situation, only LV assist devices (LVAD) have been implanted despite the presence of RV failure. However, the circulatory and histological changes in the failed RV after long term continuous-flow (CF)-LVAD support have not been fully elucidated. In this study, we hypothesized that CF-LVAD long term support may ameliorate RV failure and have a positive impact on the distressed pathology of RV. Methods: This study included 16 dilated cardiomyopathy (DCM) patients who required long-term LVAD support, for 852 ± 84(129-1607) days, before heart transplantation (HTx). Echocardiograms were performed to analyze LV and RV functions. Transmural LV tissues and RV tissues sampled before LVAD implantation and after LVAD explantation were histopathologically analyzed for LV and RV remodeling. Results: Echocardiography showed significantly reduced LV end-diastolic and end-systolic dimensions during CF-LVAD support (73 ± 11 mm to 63 ± 13.6 mm, 67 ± 12 mm to 57 ± 17 mm, P<0.05, respectively). Regarding RV function, right ventricular end-diastolic dimension (RVDd) tended to decrease (48 ± 11 mm to 43 ± 10 mm, P=0.10) and the trans tricuspid pressure gradient (TRPG) was significantly decreased during long-term LVAD support (31 ± 14.8 mmHg to 12 ± 3.2 mmHg, P=0.01). Histopathologically, the sizes of cardiomyocytes in both the LV and the RV were significantly decreased during CF-LVAD support (left: 33.1±5.1 μm to 29.1±4.0 μm, P=0.05, right: 25.5 ± 2.4 μm to 21.6 ± 3.2 μm, P=0.01) and interstitial fibrosis tended to decrease in the RV (29.5 ± 3.1 % to 19.7 ± 7.2 %, P=0.10) despite there being no change in the LV (24.9 ± 10.8 % to 27.1 ± 12.1 %, P=0.14). Conclusion: Long-term CF-LVAD support ameliorates RV failure, possibly by reducing afterload on the RV followed by unloading of LV pressure overload, and thereby exerts a positive impact on RV reverse remodeling.