Is Absolute Change in AlloMap More Informative Than Absolute Value?

Abstract

<h3>Purpose</h3> Increased variability in the non-invasive gene expression profiling (GEP) (AlloMap®) is associated with an increased risk of future events, but the association of the absolute change of below threshold GEP scores with future events has not yet been evaluated. <h3>Methods</h3> Patients from the Surveillance HeartCare Outcomes Registry (SHORE) with GEP score of < 34 had the change in GEP test calculated. The event of interest was a combination of rejection (ISHLT ≥ 2R and/or AMR ≥ 1), death, and graft dysfunction (LVEF <40% or LVEF change >=25% in a consecutive visit). Patients were divided into three groups: 1: Event - GEP within 14 days of event, 2: Prior - 3 or more GEP tests over 30 days prior to an event, 3: No Event - GEP testing in those with no event. Patients in Group 1 and 2 are paired. The N number in the x-axis label of Figure 1 are the patient number in each group. <h3>Results</h3> Of the 2029 patients in SHORE, there were 34 in the Event, 34 in the Prior to Event and 743 in the No Event groups. Age, race, and sex did not differ significantly between groups. The median GEP was highest in the Event group (34.0), compared to both Prior to Event (30.1) and No Event (30.7) groups, p<0.001. GEP scores 14 days prior to event are significantly elevated compared to GEP scores ≥30 days from event, p<0.001. The GEP scores ≥30 days are equivocal to the non-event control group, p = 0.25. Patients with GEP< 34 are significantly different at the time of event compared to scores prior to the event p=0.0046. (Figure 1) <h3>Conclusion</h3> GEP changes ahead of clinical events. Absolute GEP change may add incremental prognostic information for future events, beyond use of the absolute GEP value, especially below scores of 34. Further analysis is necessary to elucidate what absolute change in AM may be predictive of events.