CARC19: An Updated Analysis of the Impact of U.S. Heart Transplantation Allocation System Change on LVAD Patients

Abstract

Background: On 10/18/2018, a substantial U.S. heart transplantation (HT) allocation system change (ASC) became effective, resulting in lower priority for left ventricular assist device (LVAD) patients. While previous preliminary analyses demonstrated worse post-HT survival among LVAD patients between different eras, it remains unclear whether the presence of LVAD independently predicts unfavorable outcomes within the post-ASC period, especially among patients with expected longer wait times. Methods: Two cohorts of adult patients from the UNOS database were included, and their 1-year outcomes were analyzed. The pre-ASC and post-ASC cohorts encompassed patients listed between 10/18/2014 to 10/18/2017 and 10/18/2018 to 10/18/2021, respectively. We excluded patients listed before and transplanted after ASC. Cox regression models and competing risk analysis were performed. Results: 17,923 patients (post-ASC=9,684) were included (26.7% females, mean age of 53.4±12.5 years old). 3,873 had an LVAD (post-ASC=1,958), of which 3,003 underwent HT (post-ASC=1,515). Compared to LVAD patients transplanted in the pre-ASC era, those in the post-ASC era had shorter waitlist time; however, their grafts traveled longer distances with more prolonged ischemic time. After adjustment for potential confounders, LVAD was associated with a lower risk of waitlist mortality in both the pre- and post-ASC periods. Moreover, LVAD was associated with a lower HT rate (HR 0.74, 95% CI 0.70-0.79, p<0.001) and higher one-year post-HT mortality (HR 1.53, 95% CI 1.27-1.84, p<0.001) than those without long-term devices in the post-ASC. Notably, these differences were not observed in the pre-ASC. The association between LVAD and higher post-HT mortality was no longer seen after adjustment for the effect modification by ASC. Conclusions: Our findings suggest that LVAD therapy saves patients’ lives while waiting for HT. However, the ASC brought several changes to practice, which might be associated with increased post-HT mortality observed in patients bridged with LVAD. Further studies are needed to identify the highest-risk subgroups among LVAD patients to promote equity in donor organ allocation.