Cardiac magnetic resonance assessment of acute rejection and cardiac allograft vasculopathy in pediatric heart transplant

BACKGROUND

In pediatric heart transplant (PHT), cardiac catheterization with endomyocardial biopsy (EMB) is standard for diagnosing acute rejection (AR) and cardiac allograft vasculopathy (CAV) but is costly and invasive.

OBJECTIVES

To evaluate the ability of cardiac magnetic resonance (CMR) to noninvasively identify differences in PHT patients with AR and CAV.

METHODS

Patients were enrolled at three children's hospitals. Data were collected from surveillance EMB or EMB for-cause AR. Patients were excluded if they had concurrent diagnoses of AR and CAV, CMR obtained >7days from AR diagnosis, they had EMB negative AR, or could not undergo contrasted, unsedated CMR. Kruskal-Wallis test was used to compare groups: (1) No AR or CAV (Healthy), (2) AR, (3) CAV. Wilcoxon rank-sum test was used for pairwise comparisons.

RESULTS

Fifty-nine patients met inclusion criteria (median age 17years [IQR 15-19]) 10 (17%) with AR, and 11 (19%) with CAV. AR subjects had worse left ventricular ejection fraction compared to Healthy patients (p = 0.001). Global circumferential strain (GCS) was worse in AR (p = 0.054) and CAV (p = 0.019), compared to Healthy patients. ECV, native T1, and T2 z-scores were elevated in patients with AR.

CONCLUSIONS

CMR was able to identify differences between CAV and AR. CAV subjects had normal global function but abnormal GCS which may suggest subclinical dysfunction. AR patients have abnormal function and tissue characteristics consistent with edema (elevated ECV, native T1 and T2 z-scores). Characterization of CMR patterns is critical for the development of noninvasive biomarkers for PHT and may decrease dependence on EMB.

Focus on Paediatric Restrictive Cardiomyopathy: Frequently Asked Questions

Restrictive cardiomyopathy (RCM) is characterized by restrictive ventricular pathophysiology determined by increased myocardial stiffness. While suspicion of RCM is initially raised by clinical evaluation and supported by electrocardiographic and echocardiographic findings, invasive hemodynamic evaluation is often required for diagnosis and management of patients during follow-up. RCM is commonly associated with a poor prognosis and a high incidence of heart failure, and PH is reported in paediatric patients with RCM. Currently, only a few therapies are available for specific RCM aetiologies. Early referral to centres for advanced heart failure treatment is often necessary. The aim of this review is to address questions frequently asked when facing paediatric patients with RCM, including issues related to aetiologies, clinical presentation, diagnostic process and prognosis.

Caution in the use of sedation and endomyocardial biopsy for the management of pediatric acute heart failure caused by endocardial fibroelastosis

Endocardial fibroelastosis (EFE) is commonly considered to be an inflammatory reactive lesion of hyperplasia and deposition of tissue fibers and collagen in the endocardium and/or subendocardium, which is strongly associated with endocardial sclerosis, ventricular remodeling and acute and chronic heart failure, and is one of the important causes for pediatric heart transplantation. Early diagnosis and treatment are the key factors in determining the prognosis of the children. In this paper, we would like to highlight the potential unintended consequences of the use of sedation and biopsy for pediatric acute heart failure caused by EFE and the comprehensive considerations prior to clinical diagnosis.

Caution in the use of sedation and endomyocardial biopsy for the management of pediatric acute heart failure caused by endocardial fibroelastosis

Endocardial fibroelastosis (EFE) is commonly considered to be an inflammatory reactive lesion of hyperplasia and deposition of tissue fibers and collagen in the endocardium and/or subendocardium, which is strongly associated with endocardial sclerosis, ventricular remodeling and acute and chronic heart failure, and is one of the important causes for pediatric heart transplantation. Early diagnosis and treatment are the key factors in determining the prognosis of the children. In this paper, we would like to highlight the potential unintended consequences of the use of sedation and biopsy for pediatric acute heart failure caused by EFE and the comprehensive considerations prior to clinical diagnosis.

Leitlinie Myokarditis der Deutschen Gesellschaft für Pädiatrische Kardiologie

This consensus statement presents updated recommendations on diagnosis and treatment of myocarditis in childhood.

Clinical characteristics and outcome of biopsy-proven myocarditis in children - Results of the German prospective multicentre registry "MYKKE"

BACKGROUND

Heart failure (HF) due to myocarditis might not respond in the same way to standard therapy as HF due to other aetiologies. The aim of this study was to investigate the value of endomyocardial biopsies (EMB) for clinical decision-making and its relation to the outcome of paediatric patients with myocarditis.

METHODS

Clinical and EMB data of children with myocarditis collected for the MYKKE-registry between 2013 and 2020 from 23 centres were analysed. EMB studies included histology, immunohistology, and molecular pathology. The occurrence of major adverse cardiac events (MACE) including mechanical circulatory support (MCS), heart transplantation, and/or death was defined as a combined endpoint.

RESULTS

Myocarditis was diagnosed in 209/260 patients: 64% healing/chronic lymphocytic myocarditis, 23% acute lymphocytic myocarditis (AM), 14% healed myocarditis, no giant cell myocarditis. The median age was 12.8 (1.4-15.9) years. Time from symptom-onset to EMB was 11.0 (4.0-29.0) days. Children with AM and high amounts of mononuclear cell infiltrates were significantly younger with signs of HF compared to those with healing/chronic or healed myocarditis. Myocardial viral DNA/RNA detection had no significant effect on outcome. The worst event-free survival was seen in patients with healing/chronic myocarditis (24%), followed by acute (31%) and healed myocarditis (58%, p = 0.294). A weaning rate of 64% from MCS was found in AM.

CONCLUSIONS

EMB provides important information on the type and stage of myocardial inflammation and supports further decision-making. Children with fulminant clinical presentation, high amounts of mononuclear cell infiltrates or healing/chronic inflammation and young age have the highest risk for MACE.

Recent advances in the non-invasive assessment of fibrosis using biomarkers

Fibrosis can occur in most organs and is characterised by excessive and progressive extracellular matrix deposition and destruction of normal tissue architecture and function. In many cases treatment options are limited. Fibrotic diseases are therefore associated with high morbidity and mortality. Tissue biopsies remain a key part of diagnosing fibrosis; however, due to their invasive nature, tissue biopsies are unsuitable for monitoring disease progression. In some cases, tissue biopsies carry an unacceptable risk of mortality to the patient. Furthermore, assessing fibrosis via tissue biopsy is severely limited by the heterogenetic nature of fibrotic diseases and suffers from both sampling bias and observer variation/bias. The search for less invasive methods of diagnosing and monitoring fibrosis has led to the identification of many new biomarkers, many of which can be measured in serum in a so-called 'liquid biopsy' or can be imaged using state-of-the-art imaging modalities. These approaches have the potential to dramatically improve the diagnosis and monitoring of disease, and improve the design of clinical trials in to novel fibrotic therapies. This review summarises some of the recent advances in identifying novel biomarkers to diagnose and monitor fibrosis non-invasively.