Early immune biomarkers and intermediate‐term outcomes after heart transplantation: Results of Clinical Trials in Organ Transplantation‐18

: Clinical Trials in Organ Transplantation-18 (CTOT-18) is a follow-up analysis of the 200-subject multicenter heart transplant CTOT-05 cohort. CTOT-18 aimed to identify clinical, epidemiologic, and biologic markers associated with adverse clinical events past 1 year posttransplantation. We examined various candidate biomarkers including serum antibodies, angiogenic proteins, blood gene expression profiles, and T cell alloreactivity. The composite endpoint (CE) included death, retransplantation, coronary stent, myocardial infarction, and cardiac allograft vasculopathy. The mean follow-up was 4.5 ± SD 1.1 years. Subjects with serum anti-cardiac myosin (CM) antibody detected at transplantation and at 12 months had a higher risk of meeting the CE compared to those without anti-CM antibody (hazard ratio [HR] = 2.9, P = .046). Plasma VEGF-A and VEGF-C levels pretransplant were associated with CE (odds ratio [OR] = 13.24, P = .029; and OR = 0.13, P = .037, respectively). Early intravascular ultrasound findings or other candidate biomarkers were not associated with the study outcomes. In conclusion, anti-CM antibody and plasma levels of VEGF-A and VEGF-C were associated with an increased risk of adverse events. Although this multicenter report supports further evaluation of the mechanisms through which anti-CM antibody and plasma angiogenesis proteins lead to allograft injury, we could not identify additional markers of adverse events or potential novel therapeutic targets.