Evaluation of Myocardial Perfusion and Immune Cell Response in Cardiac Allograft Dysfunction of Heart-Transplant Patients

Background We investigated the myocardial perfusion differences and changes in immune cell response in heart-transplant patients with nonspecific graft dysfunction (NGD) compared to cardiac allograft vasculopathy (CAV) patients and normal heart-transplant patients. Methods and Results We prospectively studied 17 heart-transplant patients (59.8±14.1 years, 78% male) from January to June 2016. Regadenoson stress cardiac MRI was performed in the patients and peripheral blood obtained contemporaneously to isolate peripheral blood mononuclear cells (PBMCs). Stress myocardial perfusion showed significantly decreased myocardial perfusion using maximum upslope method in NGD and CAV patients compared to normal heart-transplant patients. Myocardial scar by late gadolinium enhancement also was significantly increased in nonspecific graft dysfunction patients compared to normal. Evaluation of PBMCs by flow cytometry showed a trend towards increased activated HLA-DR + T cells in NGD patients compared to normal. Clinical outcomes for cardiac hospitalization, allograft loss/retransplant, death were assessed at 8 years. Conclusions NGD shows decreased stress myocardial perfusion by cardiac MRI and a trend towards increased activated T cells in PBMCs, suggestive of an immune-mediated cause for allograft dysfunction.