The Safety of a Non-Invasive Monitoring Protocol in Heart Transplant Recipients

Abstract

Purpose Heart transplant (HT) recipients require monitoring for allograft rejection with frequent endomyocardial biopsies (EMB). The aim of this study was to evaluate the safety of transitioning heart transplant recipients to a non-invasive monitoring protocol utilizing HeartCare (combination of gene expression profiling [Allomap] and donor derived cell free DNA [Allosure]). Methods This is a prospective single-center cohort study evaluating the utilization of HeartCare from as early as one month post-HT. Positive Allomap test was defined as ≥32 in patients ≤6 months and ≥34 in patients > 6 months post-HT. Positive Allosure test was defined as ≥0.12%. Positive biopsy included ISHLT Grades ≥1B. Results 320 heart transplant recipients enrolled to this study. Mean age was 57.5±14.0, 231 were males (72.0%). There was a total of 523 HeartCare blood tests drawn and 148 biopsies were performed (Figure). Of 82 patients with elevated Allomap and Allosure, only 7 (8.5%) of them had a confirmed rejection episode. Among 71 patients with elevated Allosure with normal Allomap, only 2 (2.8%) patients had confirmed rejection. 2 patients (4.3%) with negative Allomap and Allosure had rejection. During the study period 55 patients (17.2%) were admitted to the hospital for a total of 67 admissions. 17 patients were admitted for rejection (5.3%). None of the patients died during the study period. Conclusion Transitioning from invasive endomyocardial biopsy monitoring to a non-invasive HeartCare protocol in HT recipients seems feasible based on the high negative value of the combined Allomap and Allosure tests. However, further study is needed to follow the long-term outcomes and presence of rejection in patients post-transplant with this protocol.