Abstract
Acute cellular rejection (ACR) compromises graft function after heart transplantation (HTX). The purpose of this study was to describe systolic myocardial deformation in pediatric HTX and to determine whether it is impaired during ACR. Eighteen combined cardiac magnetic resonance imaging (CMR)/endomyocardial biopsy (EMBx) examinations were performed in 14 HTX patients (11 male, age 13.9 ± 4.7 years; 1.2 ± 1.3 years after HTX). Biventricular function and left ventricular (LV) circumferential strain, rotation, and torsion by myocardial tagging CMR were compared to 11 controls as well as between patients with and without clinically significant ACR. HTX patients showed mildly reduced biventricular systolic function when compared to controls [LV ejection fraction (EF): 55 ± 8% vs. 61 ± 3, p = 0.02; right ventricular (RV) EF: 48 ± 7% vs. 53 ± 6, p = 0.04]. Indexed LV mass was mildly increased in HTX patients (67 ± 14 g/m2 vs. 55 ± 13, p = 0.03). LV myocardial deformation indices were all significantly reduced, expressed by global circumferential strain (−13.5 ± 2.3% vs. −19.1 ± 1.1%, p < 0.01), basal strain (−13.7 ± 3.0% vs. −17.5 ± 2.4%, p < 0.01), mid-ventricular strain (−13.4 ± 2.7% vs. −19.3 ± 2.2%, p < 0.01), apical strain (−13.5 ± 2.8% vs. −19.9 ± 2.0%, p < 0.01), basal rotation (−2.0 ± 2.1° vs. −5.0 ± 2.0°, p < 0.01), and torsion (6.1 ± 1.7° vs. 7.8 ± 1.1°, p < 0.01). EMBx demonstrated ACR grade 0 R in 3 HTX cases, ACR grade 1 R in 11 HTX cases and ACR grade 2 R in 4 HTX cases. When comparing clinically non-significant ACR (grades 0–1 R vs. ACR 2 R), basal rotation, and apical rotation were worse in ACR 2 R patients (−1.4 ± 1.8° vs. −4.2 ± 1.4°, p = 0.01 and 10.2 ± 2.9° vs. 2.8 ± 1.9°, p < 0.01, respectively). Pediatric HTX recipients demonstrate reduced biventricular systolic function and decreased myocardial contractility. Myocardial deformation indices by CMR may serve as non-invasive markers of graft function and, perhaps, rejection in pediatric HTX patients.
Highlights
Advances in donor and recipient selection, surgical techniques, and medical management have substantially improved survival of children after heart transplantation (HTX) [1,2,3]
Abnormal left ventricular (LV) torsion and biventricular systolic dysfunction have been reported in pediatric HTX recipients [5, 7,8,9,10,11], and reduced LV ejection fraction (EF) has been proposed as a non-invasive marker of Acute cellular rejection (ACR) in children [7]
The study adds the following to our understanding of cardiovascular health in pediatric patients after HTX: (a) Children after HTX have decreased biventricular systolic function; (b) They show evidence of decreased myocardial contractility as evidenced by abnormal circumferential strain, rotation, and torsion; and (c) LV rotation is reduced with increased severity of ACR
Summary
Advances in donor and recipient selection, surgical techniques, and medical management have substantially improved survival of children after heart transplantation (HTX) [1,2,3]. Despite these encouraging developments, cardiovascular health remains compromised in many children and adolescents after HTX. Acute cellular rejection (ACR)— its prevalence has decreased over the years—remains an important cause of morbidity and graft loss and is one of the factors compromising the long-term. Acute cellular rejection is a risk factor for graft loss, cardiac dysfunction, coronary vascular disease, and mortality. Suitable alternative tests for ACR are desirable for pediatric HTX patients [2]
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