Cardiac Allograft Rejection in the Current Era of Continuous Flow Left Ventricular Assist Devices

Abstract: Objective Left ventricular assist device (LVAD) implantation has been shown to increase allosensitization prior to orthotopic heart transplantation (OHT), but the influence of LVAD support on post-transplant rejection is controversial. This study examines the postoperative incidence of acute cellular rejection (ACR) in patients bridged with continuous flow LVAD (CF-LVAD) relative to Primary Transplant (Primary Tx). Methods All patients who underwent OHT at our institution between July 2006 and March 2019 were retrospectively reviewed (n=395). Patients were classified into Primary Tx (n=145) and CF-LVAD (n=207) groups. Propensity score matching on thirteen covariates implemented a 0.1 caliper logistic model with nearest neighbor 1:1 matching. Development of moderate to severe grade (2R/3R) rejection was evaluated using a competing risks model. Potential predictors of 2R/3R ACR were evaluated using Fine-Gray regression on the marginal subdistribution hazard. Results Propensity score matching yielded 122 patients in each group (n=244). At 12 and 24 months, the cumulative incidence of 2R/3R ACR was 17% and 23% for the CF-LVAD group and 26% and 31%, respectively, for the Primary Tx group (P=0.170) (Figure 1). CF-LVAD was not predictive of 2R/3R rejection on multivariable Fine-Gray regression (SHR 0.73 (0.40, 1.33), P=0.301). There was no difference in the five-year incidence of antibody mediated rejection (10% (n=12) vs 9% (n=11); P=0.827). Conclusions After adjusting for covariates, CF-LVAD was not associated with an increased risk of moderate to severe ACR in the 24 months after cardiac transplantation. Further investigation is warranted with larger cohorts, but CF-LVAD may have minimal impact on post-transplant ACR.