Association Between Center Level Characteristics And 1-Month Post-LVAD Implant Risk Standardized Mortality Rates

Abstract

<h3>Background</h3> As more durable continuous flow (CF) left ventricular assist device (LVAD) are implanted, the number of implanting centers has increased. Whether center level characteristics influence post-implantation outcomes is not fully defined. Therefore, we sought to determine center level characteristics associated with risk standardized mortality rates (RSMR) at 1-month post-implant. <h3>Methods</h3> Data from 167 centers that implanted CF-LVADs in 19,503 patients between 2008-2017 in the INTERMACS were analyzed. The 1-month post-implantation center RSMR was generated with a multivariable logistic regression model adjusting for 50 patient-level characteristics at implantation for all LVAD treatment strategies. Data from patients who were transplanted within 1-month or who had ≥5 missing variables were excluded. RSMR estimates underwent Bayesian correction to account for the influence of unbalanced inter-center CF LVAD volumes. Center-level characteristics were compared by the Cochran-Armitage trend or Chi-square tests across tertiles of the 1-month RSMR where appropriate. <h3>Results</h3> The overall median [25-75^th quartile] 1-month RSMR was 4% (1-6%). Median 1-month RSMR by center tertiles was 0% (0-1%), 4% (3-4%), and 7% (6-9%) respectively. Both greater annual and greater cumulative center LVAD volume were associated with lower 1-month RSMR (P <0.04 for both, figure A-B). Higher annual destination therapy CF-LVAD implantation volume (P=0.03), but not bridge-to-transplant CF-LVAD implantation volume (P=0.14) was associated with a lower 1-month RSMR. An implanting center's percentage of destination therapy or bridge-to-transplant strategy CF-LVAD devices implanted was also not associated with 1-month RSMR (Figure C-F). Higher rates of a concomitant mitral valve repair, a sternal implant approach, and intraoperative ECMO or IABP removal were each associated with a lower 1-month RSMR (P<0.05 for all). Less cardiopulmonary bypass time (P<0.01), but not total surgical time (P=0.43) was associated with a lower 1-month RSMR. Lastly, there was no association with the percentage of patients with INTERMACs profile 1 and 1-month RSMR (P=0.80). <h3>Conclusions</h3> When controlling for patient-level characteristics, higher LVAD implantation volumes, higher absolute rates of DT LVAD volumes, and certain patient-management strategies by center were associated with lower 1-month RSMR. These data identify potential patterns of care by center that may influence short-term post-LVAD outcomes.