Trends in Renal Function Prior to and after LVAD Placement and Association with Post LVAD Mortality

Purpose To model renal function in an advanced heart failure population both prior to and after left ventricular assist device (LVAD) and to determine the association between pre-operative renal function trends and post-LVAD mortality. Methods Patients with a first time continuous-flow LVAD implant at a single center with renal function data before and after LVAD were included in the analysis (n=410). GFR at each time point was calculated with the CKD-EPI equation. Trends before and after LVAD were computed and plotted using Locally Estimated Scatterplot Smoothing (LOESS). GFR between 200 to 100 days prior to LVAD was regressed longitudinally to calculate a slope of GFR change prior to LVAD. Both the GFR slope and nadir of GFR prior to LVAD (Figure) were assessed as predictors of post LVAD mortality using multivariable cox regression. Results When assessed as a whole, GFR declined in the entire cohort prior to LVAD, improved with medical optimization, improved further post LVAD, and then declined again to a level that was similar to initially measured values. Each unit decrease in the GFR slope was associated with an adjusted 35% increase in post LVAD mortality (HR 1.36, 95% CI 1.15-1.51, p=0.002). With respect to the GFR nadir, each 10-unit decrease was associated with an adjusted 19% increase in post-LVAD mortality (HR 1.19, 95% CI 1.07- 1.30, p = 0.003). Models were adjusted for age, bridge to transplant status, ischemic cardiomyopathy, and diabetes. Conclusion This analysis demonstrates that renal function in the advanced heart failure population prior to LVAD is complex, with declines in renal function prior to LVAD, and the nadir of GFR prior to LVAD being associated with increased post LVAD mortality. This data suggest earlier LVAD placement prior to measurable renal deterioration may be beneficial.