Screening for rejection in symptomatic pediatric heart transplant recipients: the sensitivity of BNP

Noninvasive biomarkers for prediction and diagnosis of heart transplantation rejection

For most patients with end-stage heart failure, heart transplantation is the treatment of choice. Allograft rejection is one of the major post-transplantation complications affecting graft outcome and survival. Recent advancements in science and technology offer an opportunity to integrate genomic and other omics-based biomarkers into clinical practice, facilitating noninvasive evaluation of allograft for diagnostic and prognostic purposes. Omics, including gene expression profiling (GEP) of blood immune cell components and donor-derived cell-free DNA (dd-cfDNA) are of special interest to researchers. Several studies have investigated levels of dd-cfDNA and miroRNAs in blood as potential markers for early detection of allograft rejection. One of the achievements in the field of transcriptomics is AlloMap, GEP of peripheral blood mononuclear cells (PBMC), which can identify 11 differentially expressed genes and help with detection of moderate and severe acute cellular rejection in stable heart transplant recipients. In recent years, the utilization of GEP of PBMC for identifying differentially expressed genes to diagnose acute antibody-mediated rejection and cardiac allograft vasculopathy has yielded promising results. Advancements in the field of metabolomics and proteomics as well as their potential implications have been further discussed in this paper.

Protein and peptide biomarkers in organ transplantation

Organ transplantation is the optimal treatment choice for end-stage organ failure in pediatric patients. The ideal maintenance of a transplanted organ requires efficient monitoring tools and an effective individualized post-transplant treatment plan. Currently available post-transplant monitoring options are not ideal because of their invasiveness or their lack of sensitivity and specificity when providing an accurate assessment of transplant injury. Current research on proteins and peptides, including mass spectrometry-based proteomics, can identify novel surrogate protein and peptide biomarkers that can assist in monitoring the graft in order to correctly assess the status of the transplanted organ. In this article, we have critically reviewed current relevant literature to highlight the importance of protein and peptide biomarkers in the field of pediatric organ transplantation, the status of research findings in the field of protein and peptide biomarkers in different organ transplantation and factors that impact and inhibit the progression of protein biomarker discovery in the field of solid-organ transplantation in pediatrics.

Outpatient management of pediatric heart failure

The management of heart failure in children is becoming a specialized discipline within pediatric cardiology. Unlike the treatment of heart failure in adults, for which an extensive body of literature supports current treatment regimens, management of heart failure in children is largely guided by extrapolation from adult studies and expert opinion. This review focuses on the current state-of-the-art with respect to the outpatient management of heart failure in children.

Brain-type natriuretic peptide correlates with right heart pressures in a cross section of pediatric heart transplant patients

Serum brain-type natriuretic peptide level (BNP) correlates with hemodynamic parameters measured during cardiac catheterization in adult patients with heart failure. We sought to describe the relationship of BNP with invasive hemodynamic measurements and cellular rejection in children following OHT. Children undergoing catheterization for OHT surveillance had simultaneous measurement of BNP. A total of 62 subjects were studied. The median BNP was 171 pg/mL (range 19-1130). There were significant positive correlations between BNP and mean PAP (R=0.33, p=0.009), RVSP (R=0.25, p=0.05), RVEDP (R=0.29, p=0.02), and mean RAP (R=0.39, p=0.002). Rejection grade varied from 0 to 3A (58 patients < ISHLT 3A and four patients ≥ ISHLT 3A). There was no significant difference in BNP based on cellular rejection grade. In a cohort of pediatric patients after heart transplantation, BNP correlates with direct measurements of right-sided pressures, but not with other hemodynamic measurements, time from transplant or rejection grade. This suggests that BNP may have a complimentary role in the monitoring of children following heart transplantation.

Humoral Rejection after Pediatric Heart Transplantation: A Case Report

Humoral rejection was observed 2 years after heart transplantation in a 10-year-old African American girl with sickle cell disease. Hemodynamic compromise developed, and the patient started treatment with extracorporeal membrane oxygenation within 24 hours of admission. With cellular rejection initially believed to be the cause, administration of thymoglobulin and high-dose steroids was initiated. Human leukocyte antigen antibody analysis revealed high titers of donor-specific class I and II antibodies. Aggressive treatment for antibody-mediated rejection was started with plasmapheresis and administration of intravenous immune globulin and ritux-imab. The patient displayed clinical signs of infection and was treated with antimicrobial, antiviral, and antifungal agents. Computed tomography of the chest suggested asperigillous infection. The patient underwent a left upper lobectomy. The patient recovered and has done well, now 4 years after having received the heart transplant. Antibody-mediated rejection should be considered early in heart transplant patients presenting with hemodynamic compromise and may respond to aggressive antibody and B cell–directed therapy. Vigilance for secondary infections, especially during treatment for rejection, is crucial.

Practical application of natriuretic peptides in paediatric cardiology

It is still uncertain if cardiac natriuretic peptides are useful biomarkers in paediatric cardiology. In this review we identify four clinical scenarios in paediatric cardiology, where clinical decision-making can be difficult, and where we feel the paediatric cardiologists need additional diagnostic tools. Natriuretic peptide measurements could be that extra tool. We discuss and suggest N-terminal pro-B-type natriuretic peptide and B-type natriuretic peptide reference intervals for children without cardiovascular disease and cut-off points for the four specific paediatric heart conditions. We conclude that in premature neonates with persistent arterial ducts; in teenagers with tetralogy of Fallot and pulmonary regurgitation; and in children with heart transplants and potential allograft rejection cardiac peptides can provide the clinician with additional information, but in children with atrial septal defects the peptides are not helpful in guiding treatment or follow-up.