Interventricular Septal Output While Supported on LVAD Therapy

Abstract

Purpose The effects of left ventricular unloading on septal function in patients with left ventricular assist devices (LVADs) have not been well characterized. The purpose of this study was to evaluate the relationship between markers of septal function with echocardiography in relationship to RV dysfunction and late RV failure after LVAD implantation. Methods A retrospective study was conducted of patients supported on centrifugal-flow LVADs implanted over a 10-year period. Echocardiographic data (quantitative and qualitative measures of RV function and LV remodeling) were collected pre-operatively and up to two years following LVAD implantation. Interventricular septum (IVS) measurements were taken at end-systole and end-diastole. Interventricular-septal output (ISO) was calculated using the formula: (IVSs-IVSd)*heart rate. Results 110 patients (65% male, mean age 57±14yrs) were included. 83 patients (77%) received a HeartWare and 25 patients (23%) received a HeartMate 3. An immediate and sustained reduction in both lateral annulus systolic velocity (RVS’) and TAPSE were observed after implant (P<.0001). However, while LVEF rose slightly on average over the follow-up period, ISO gradually decreased over time (P<.0001), driven by a diminishment of IVSs-IVSd. While ISO was not predictive of late RV failure, a decrease in ISO by 25% or greater from pre-implant to hospital discharge was associated with late RV failure (OR 4.8; 95% CI 1.4-16.5; P=0.012). Conclusion RV function is known to be influenced by unique mechanical ventricular interdependence and we demonstrate that measurement of ISO may be a useful marker in assessing RV dysfunction and predicting RV failure in patients following LVAD implantation. The effects of left ventricular unloading on septal function in patients with left ventricular assist devices (LVADs) have not been well characterized. The purpose of this study was to evaluate the relationship between markers of septal function with echocardiography in relationship to RV dysfunction and late RV failure after LVAD implantation. A retrospective study was conducted of patients supported on centrifugal-flow LVADs implanted over a 10-year period. Echocardiographic data (quantitative and qualitative measures of RV function and LV remodeling) were collected pre-operatively and up to two years following LVAD implantation. Interventricular septum (IVS) measurements were taken at end-systole and end-diastole. Interventricular-septal output (ISO) was calculated using the formula: (IVSs-IVSd)*heart rate. 110 patients (65% male, mean age 57±14yrs) were included. 83 patients (77%) received a HeartWare and 25 patients (23%) received a HeartMate 3. An immediate and sustained reduction in both lateral annulus systolic velocity (RVS’) and TAPSE were observed after implant (P<.0001). However, while LVEF rose slightly on average over the follow-up period, ISO gradually decreased over time (P<.0001), driven by a diminishment of IVSs-IVSd. While ISO was not predictive of late RV failure, a decrease in ISO by 25% or greater from pre-implant to hospital discharge was associated with late RV failure (OR 4.8; 95% CI 1.4-16.5; P=0.012). RV function is known to be influenced by unique mechanical ventricular interdependence and we demonstrate that measurement of ISO may be a useful marker in assessing RV dysfunction and predicting RV failure in patients following LVAD implantation.