Evaluation of Acute Rejection by Measuring Strain and Strain Rate in Children With Heart Transplant: A Preliminary Report

Abstract

Objectives: Asymptomatic rejection after heart transplant is difficult to detect by noninvasive methods. The present study investigated the efficacy of echocardiographic strain and the strain rate imaging method in detecting rejection after pediatric heart transplant.

Materials and Methods: Fourteen pediatric patients with heart transplant were examined both with endomyocardial biopsy and strain imaging. Patients were divided into 2 groups: group 1 included patients with rejection, and group 2 included patients without rejection. Patients underwent endomyocardial biopsy at regular intervals. Regional systolic function was evaluated by longitudinal myocardial peak systolic values of strain and of strain rate. Differences between the 2 groups were assessed with unpaired t test or Mann-Whitney U test.

Results: Acute rejection was detected in 7 patients (4 were female patients). Cardiac diagnosis was restrictive cardiomyopathy in 3 patients, dilated cardiomyopathy in 3 patients, and complex congenital heart disease in 1 patient. After heart transplant, 6 patients had rejection once and 1 patient had rejection twice. Evaluation of biopsy samples revealed grade IB rejection in all patients in group 1. Systolic functions of the 6 patients were determined as normal in standard echocardiographic examination. There were no significant differences in deformation and deformation rates between group 1 and 2 except in midseptal region (P<.05).

Conclusions: One of the most significant complications in patients with heart transplant is rejection. Our results suggested that myocardial strain imaging may be valuable in defining low-grade rejection.