Right Ventricular Dysfunction by Echocardiography Is an Early Marker of Evolving Cardiac Allograft Vasculopathy in Children After Heart Transplantation

Background Cardiac allograft vasculopathy (CAV) is the leading cause of late graft loss in children after pediatric heart transplantation (HTx). Coronary angiography, the reference standard for diagnosis, is invasive and carries a risk of complications. Noninvasive echocardiographic methods to reliably identify CAV in children have not yet been defined. Methods This study assessed the utility of functional echocardiography (FE) in the diagnosis of CAV in children. We prospectively assessed all children (< 18 years old) post‐HTx during routine clinical surveillance between 2005 and 2020. For this study, we compared patients diagnosed with CAV (angiographic ISHLT criteria) with transplanted children without CAV, with FE at the time of diagnosis (d‐CAV) and 6–12 months before diagnosis (pre‐CAV), and evaluated clinical risk factors. Results We identified 10 children with CAV and 11 matched controls (CON). Right ventricular longitudinal strain (RV LS) and strain rate (RV LSR) were reduced at d‐CAV (d‐CAV RV LS, 12.1% [9.2,16.1] vs. CON RV LS, 21.5% [18.2,25.7]; d‐CAV RV LSR, 0.75%/s [0.48, 0.98] vs. CON RV LSR, 1.35%/s [0.95,1.50], p < 0.01 for all) and pre‐CAV (pre‐CAV RV LS, 17.3% [10.8,20.2] vs. CON RV LS, 21.5% [18.2,25.7]; pre‐CAV RV LSR 0.95%/s [0.80,1.10] vs. CON RV LSR, 1.35%/s [0.95,1.50], p ≤ 0.05 for all). Patients with CAV were more likely to have class II donor‐specific antibodies ( p = 0.01). Conclusion Right ventricle systolic strain parameters were reduced as early as 12 months prior to CAV diagnosis, while the left ventricle functional parameters remained preserved. FE of the right ventricle may be a useful noninvasive tool for early recognition of developing CAV in transplanted children.