78 Do Longitudinal Stable Lower AlloMap® Scores Portend Better Outcomes after Heart Transplantation?

Abstract

Purpose AlloMap® is a non-invasive gene expression profile (GEP) test with a high negative predictive value for moderate/severe cellular rejection. We have observed a cohort of patients with consistently low GEP scores. Whether this reflects a group of patients with unique characteristics and a more quiescent immunological state manifest by improved outcomes is of interest in this study. Methods and Materials A low GEP score was defined within the lowest quartile of all GEP scores from a large database of all patients with at least 3 tests performed at the reference lab. Two groups from the IMAGE multicenter clinical outcomes study were retrospectively defined: Group 1 had a mean score in the lowest quartile (GEP ≤27.5), and patients with scores greater than 2 standard deviations from the mean were excluded; Group 2 had mean scores <34, the clinically accepted threshold for low rejection risk, that did not meet Group 1 criteria. Clinical outcomes of interest included a composite primary endpoint (rejection with hemodynamic compromise, graft dysfunction due to other causes, and death/retransplantation), any treated rejection, left ventricular ejection fraction (LVEF), and hospitalizations. Results We evaluated 1684 scores from 353 patients from IMAGE. Group 1 had 59 patients with 250 scores; Group 2 had 294 patients with 1434 scores. Basic demographics including age, gender, and race were similar between groups. Mean time since transplant was 21 months in both groups. Outcomes are shown below. Table 1. Outcomes (events) Group 1 (GEP ≤27.5) Group 2 (GEP <34) p value Primary Endpoint 1 53 0.027 Treated Rejection 2 66 0.017 Average LVEF (%) 63.7 62.4 0.001 Hospitalizations 21 180 0.16 Full-size table Table options View in workspace Download as CSV Conclusions Patients with consistently low GEP scores have a significantly lower incidence of adverse outcomes compared to patients in Group 2 despite similar demographics. With further characterization of this group, and if validated on a larger scale, more personalized post-transplant care to tailor immunosuppression down may be possible.