Poor Functional Status Prior to Bridge-to-transplant Left Ventricular Assist Device Therapy is not Associated with Reduced Survival in Heart Transplant Recipients: Analysis of the United Network for Organ Sharing (UNOS) Registry

Introduction Left ventricular assist devices (LVAD) are commonly used as a bridge-to-transplant (BTT) therapy for patients with advanced heart failure. Poor functional status (FS) is known to negatively affect post-transplant outcomes after heart transplant (HTX). In this study, we sought to evaluate the impact of poor FS prior to BTT-LVAD implantation on post-HTX outcomes. Methods Data from the UNOS database from 2008-2017 were obtained for HTX recipients that underwent continuous-flow LVAD implantation after being listed for HTX with complete Karnofsky Performance Status (KPS) score both at listing (Pre-LVAD) and time of HTX. Poor FS was defined by KPS ≤ 40 (require total assistance) and good FS was defined by KPS > 40 (require some or no assistance). Improvement of FS was defined as a change from pre-LVAD poor FS to good FS at HTX. Multivariate logistic regression adjusting for baseline/pre-HTX characteristics was performed to assess the association of pre-LVAD FS and post-HTX survival and predictors of FS improvement. Results We included 2,812 patients (mean age 52 years, 80% male, 41% on inotrope) listed for HTX before LVAD implantation. Median time from listing to LVAD surgery was 21 (IQR 4-114) days. A total of 48% had poor FS at listing before LVAD. Patients with poor FS were younger, had lower body mass index (BMI), more likely to be on inotrope at listing and had worse hemodynamics. Time to LVAD implantation was shorter in poor FS group but no difference in LVAD support duration. There was no significant difference between poor FS and good FS group in 30-day (96.5% vs. 96.1%, p=0.59) and 1-year post-HTX survival (90.2% vs. 88.7%, p=0.23). Poor FS did not significantly affect 30-day (adjusted OR = 0.9, p=0.64) or 1-year post-HTX survival (adjust OR = 0.9, p=0.54). Of 1,342 patients with pre-LVAD poor FS, 715 (53%) had improvement in FS at HTX. Predictors of FS improvement were longer LVAD support duration and lower BMI. Among pre-LVAD poor FS group, patients with improved FS had significantly higher 1-year post-HTX survival (92.1% vs. 88.0%, p=0.015) but no significant difference in 30-day post-HTX survival (97.0 % vs. 95.8%, p=0.223). Improved FS in patients with pre-LVAD poor FS was significantly associated with higher 1-year survival (adjusted OR = 1.6, p= 0.03). Conclusions Poor functional status was observed in up to 50% of BTT-LVAD candidates; however, it doesn't negatively affect post-HTX survival. After BTT-LVAD support, half of patients with pre-LVAD poor FS have improved FS which is significantly associated with higher post-HTX survival. Urgent BTT-LVAD in selected patients with poor FS is a reasonable option prior to HTX.