system, T cell depletion can be accomplished

is most often seen in patients with a history of medication non-compliance who have diffi­culty maintaining adequate immunosuppression levels. Confounding issues that can contribute to late acute rejection include new prescrip­tion medications [50], herbal medications, and nutritional supplements that can interact with immunosuppressants. Infections and/or gastro­intestinal conditions may alter immunosuppres­sion through concentration levels by impairing medication absorption. Patients with prior rejec­tion > 6 months post-transplant remain at ele­vated risk for late acute rejection. Additional risk factors for late acute rejection include the presence of DSA, CNI-reduced or -free main­tenance immunosuppression, younger recipient age, and recipient female gender. For younger patients who transition from pediatric HTx programs to adult HTx programs, this period of time can be particularly challenging [51]. Re-education on the importance of medication adherence, as well as assessment of psychoso­cial and mental health support, are important during this transition [52]. For patients at ele­vated risk, it is reasonable to consider continued surveillance for late acute rejection with either non-invasive or invasive testing greater than 1-year post-HTx. Late acute rejection is often AMR. However, CAV, a form of chronic rejec­tion, should also be evaluated in patients pre­senting with signs and symptoms of late acute rejection. Invasive coronary angiography should be considered in patients at risk for late acute rejection with a history of dnDSA or history of AMR [53]. Patients with late acute rejection will need closer follow-up and, if treated for rejec­tion, repeat EMB to document improvement or resolution of late acute rejection. When risks outweigh benefits, invasive testing should yield to non-invasive testing.