Non-Invasive Surveillance for Cardiac Allograft Rejection Using an Echocardiographic Rejection Score in Pediatric Heart Transplant Recipients

Abstract

<h3>Purpose</h3> Cardiac allograft rejection post heart transplant (HT) remains a significant cause of morbidity and mortality in pediatric HT recipients. Endomyocardial biopsy is the gold standard for diagnosis, but is invasive, expensive, and not without risks. We examine the correlation between a non-invasive echocardiographic ejection score (ERS) and clinical and echocardiographic (echo) evidence of rejection. <h3>Methods</h3> All pediatric HT patients followed at our institution who had surveillance echo using the ERS were retrospectively enrolled. Rejection is defined as any changes in clinical or echo parameters resulting in augmented immunosuppression or administration of steroids, biologics, or plasmapheresis. ERS, left ventricular relaxation index (LVRI), RR interval, diastolic time, and atrioventricular valve regurgitation were obtained from the echo reports. The ERS is scored from 0-10 and is stratified as follows: 0-4: no rejection; 5-6: possible rejection necessitating closer follow up or consideration of other clinical factors; ≥7: automatic rejection. <h3>Results</h3> Sixty-six patients were followed over an 8 year period. Mean age at HT was 6.81 years (range 22 days - 21 years). Thirty-five (53%) patients were male. Primary indication for HT was cardiomyopathy in 54.5% (n=36), congenital heart disease in 44% (n=29), and other in 1.5% (n=1). Fifty-eight episodes of acute or ongoing rejection were treated based on clinical evidence. The ERS correlated weakly with LVRI (r = -.191, p < .01), RR interval (r = .117, p <.01), diastolic time (r = .159, p <.01), and new onset mitral or tricuspid regurgitation (MR/TR) (r = .168, p <.01). The ERS did not correlate with rejection identified by changes in clinical status alone (r = .015, p = .428). <h3>Conclusion</h3> ERS appears to be a useful non-invasive diagnostic tool for early detection of rejection in heart transplant pediatric patients. A larger study is needed to determine the diagnostic utility of this non-invasive ERS.