Frontiers in Surveillance of the Transplanted Heart: What Lies Beneath

This session explores two major topics that dictate the long-term survival of heart transplant recipients: cardiac allograft vasculopathy (CAV) and rejection - detection and treatment CAV remains one of the top three causes of death for heart transplant recipients who survive beyond 10 years after orthotopic heart transplantation. CAV affects up to 50% of heart transplant recipients after 10 years after transplant, and ISHLT CAV 3 confers a 50% five-year mortality or re-transplant rate. Recent cohorts have delineated different trajectories of CAV progression and prediction models have been created to further identify risk of developing severe disease. Furthermore, innovations in non-invasive imagining, particularly with positron tomography (PET) absolute myocardial blood flow quantification and stress cardiac magnetic resonance imaging (MRI) have further enhanced non-invasive detection of CAV. Newer methods of assessing microcirculatory health including index of microcirculatory resistance (IMR) have shown value in recent publications. The next frontier is to utilize this information to select therapies that change the progression of CAV and survival of the patient. Meanwhilerejection surveillance following heart transplantation has changed significantly over the past few years with increasing clinical use of donor-derived cell-free DNA (dd-cfDNA) and molecular microscopy. With the increased availability of noninvasive testing, there have been large shifts in how rejection surveillance is performed. This has decreased use of endomyocardial biopsy in favor of non-invasive testing and also requires that programs integrate multiple sources of nuanced data to determine the presence of cellular or antibody-mediated rejection. Additionally, techniques that expand the reproducibility and diagnostic yield of biopsies, such as molecular microscope and digital pathology, are rapidly emerging in clinical practice and necessitate maintenance of operator skills performing endomyocardial biopsy.