Is There Any Role of Gene Expression Profiling Test in Asymptomatic Pediatric Heart Transplant Recipients?

Abstract

Our objective was to correlate AlloMap score with acute cellular rejection (ACR) by endomyocardial biopsy (EMB), donor specific antibody (DSA), cardiac hemodynamic data, cardiac allograft vasculopathy (CAV), and allograft function by echocardiography in pediatric heart transplant (HT) recipients. Retrospective data were collected on all consecutive pediatric HT patients, who had AlloMap tests, cardiac catheterization, EMB, left ventricular shortening fraction (LV SF), ejection fraction (LV EF), and fractional area change in right ventricle (RV FAC) by echocardiography that were obtained concomitantly on same day for routine surveillance for cardiac rejections in asymptomatic patients. Fifty five patients included in the study. Median age at HT was 5.1 years (range, 0.9 -14.1). Median number of RHC was 4 and both RHC and LHC was 2 per patient. The median AlloMap score for entire cohort was 32 (range, 18-37), in both grade 0R (n=67) and grade 1R (n=140) were 32 (range, 29-35), whereas in grade 2R (n=3) score was 35 (range, 33-37). There was no significant difference in AlloMap scores between ACR grades (Fig A), DSA (Fig B), or CAV status (Fig C). There was modest correlation between AlloMap scores and mean RAP (R2 = 0.05, p = 0.002), and PCWP (R2 = 0.03, p = 0.02). Patients on Tacrolimus only had higher scores (Fig D). No correlation between AlloMap score was found with LV SF (p=0.3), LV EF (p=0.5), or RV FAC (p=0.8). AlloMap scores were higher in <2 versus ≥2 years of age at HT (Fig E), and scores were trending higher with time after HT (Fig F). AlloMap scores are not predictive of ACR in asymptomatic pediatric HT recipients. Moreover, AlloMap scores are higher in children <2 years of age at the time of HT. Monitoring of serial AlloMap scores could potentially reflect changes in allograft performance which could help determine indications for EMB. Patients have predictably higher AlloMap scores with time after HT due to changes in hemodynamics associated with cardiac remodeling.