The role of speckle tracking imaging in the noninvasive detection of acute rejection after heterotopic cardiac transplantation in rats

Abstract

Objective Acute cardiac allograft rejection continues to be the cause of graft loss and contributes to the morbidity and mortality after cardiac transplantation. Repetitive endomyocardial biopsies are necessary to monitor the eff ects of immunosuppressants after cardiac transplantation. In this study, we investigate whether speckle tracking imaging (STI) is a valuable method in assessing acute cardiac rejection.

Methods and resultsHearts from Brown Norway rats or Lewis rats were transplanted into other Brown Norway rats. Isografts and groups of allografts, either untreated or treated with cyclosporine A (CsA) at a low dose (3 mg •kg-1• d-1) or a high dose (10 mg •kg-1• d-1), were compared 7 days after transplantation. Echocardiography-derived left ventricular post wall thickness was increased only in untreated allografts. The left ventricular ejection fraction was signifi cantly lower in the allografts compared with the isografts, but allografts treated without or with low-dose CsA showed similar results .The radial velocity and systolic radial strain rate showed a lower value in untreated allografts than other grafts, but there is no signifi cant diff erence between allografts treated with high- or low-dose CsA and isografts. The circumferential strain and circumferential strain rate were comparable among the 4 groups. However, the radial strain exhibited a clear gradient in these groups (2.8 ± 1.3 in untreated allografts, 5.2 ± 0.9 in allografts treated with lowdose CsA, 6.3 ± 1.8 in allografts treated with high-dose CsA, and 12.7 ± 7.9 in isografts, P < 0.001).

Conclusions STI is able to off er a noninvasive method for detecting transplant allograft rejection.

Key Words:

• Rejection
• echocardiography
• speckle tracking imaging.