Echocardiographic detection and management of acute cardiac allograft rejection

Abstract Background Heart transplantation (HT) is the gold standart for many patients with end-stage heart failure. Despite major advances in immunosuppression, allograft rejection remains a major cause of early morbidity and mortality after HT. Acute cellular rejection (ACR) and antibody-mediated rejection (AMR) induce inflammatory myocardial injury, leading to structural and functional alterations that often precede overt systolic dysfunction. Echocardiography is a cornerstone non-invasive tool for the detection, surveillance, and management of graft dysfunction in heart transplant recipients (HTRs). Purpose To describe the echocardiographic characteristics of AR and to outline the role of echocardiography in the diagnosis, risk stratifications, and clinical management of rejection in HTRs. Methods A narrative synthesis of published evidence was performed focusing on echocardiographic markers of acute graft rejection, including myocardial structure, diastolic and systolic function, tissue Doppler imaging (TDI), and speckle tracking strain. These imaging findings were evaluated in relation to clinical presentation, cardiac biomarkers, and therapeutic decision-making in suspected or confirmed rejection. Results Acute graft rejection is associated with characteristic echocardiographic findings, including new and increasing pericardial effusion, increased left ventricular (LV) wall thickness and mass due to myocardial edema, and altered myocardial echogenicity. Diastolic dysfunction is often the earliest manifestation, characterized by reduced isovolumetric relaxation time (IVRT<90 ms), increased transmitral E-wave velocity (>100cm/s), and ratios E/e'>14. Reduced early and diastolic peak mitral annulus (e' and a') and lower systolic velocities (s') correlate with AR episodes, while stable or high velocities have a strong negative predictive value for excluding clinically significant rejection. Strain imaging can reveal myocardial dysfunction before any measurable changes in two-dimensional (2D) or Doppler echo parameters. Cutoff values of LV global longitudinal strain (GLS) <15.5% and right ventricular free wall strain (RW FW) < 17% are strongly associated with acute rejection and adverse outcomes. When echocardiographic abnormalities are accompanied by clinical heart failure and cardiac biomarkers (troponin T, NT-proBNP), early initiation of immunosuppressive therapy is warranted. Empirical treatment of rejection includes high-dose corticosteroid pulse therapy, and anti-thymocyte globulin, plasmapheresis, and intravenous immunoglobulin. Serial echocardiographic and laboratory monitoring is essential to assess therapeutic response. Conclusion Echocardiography provides essential non-invasive markers for the early detection, monitoring, and management of acute rejection after HT. It helps doctors quickly perform an examination at the bedside in the early period after heart transplantation without any risk to patients.Echocardiographic Changes in RejectionFor image description, please refer to the figure legend and surrounding text.Central IllustrationFor image description, please refer to the figure legend and surrounding text.