Abstract 724: Noninvasive Detection of Subclinical cardiac Allograft Rejection Using Velocity Vector Imaging
Background: Although acute rejection is a common problem early after heart transplantation, currently no accurate tools are available to detect acute allograft rejection. Recently, it was reported that strain and strain rate imaging provide quantitative assessment of myocardial deformation in a real-time and an automatic manner. Taken that the noninvasive detection of subclinical cardiac allograft rejection by strain echocardiography has not been well established, we aimed to evaluate transmural myocardial strain profile in heart transplant recipients.
Methods: The study population consisted of 19 patients (mean age 56±9 years, 5 female) who underwent heart transplantation and had 23 biopsies. They were divided into three groups according to the International Society of Heart and Lung Transplantation criteria: 11 biopsies (Group A) with no rejection, 7 biopsies (Group B) with mild rejection (1R/1A, 1R/1B) and 5 biopsies (Group C) with moderate/severe rejection (2R/3A). Subendocardial radial strain, subepicardial radial strain and trasmural radial strain were calculated in the posterior segment of LV short-axis view by using Velocity Vector Imaging (VVI)™ software.
Results: There were no significant differences among 3 groups in ejection fraction and subepicardial strain (Table 1⇓). Though there was no difference between group A and group B in terms of transmural strain, that of group C was significantly reduced compared to that of group A. Moreover, subendocardial strain was significantly lower in group B and group C compared to that of group A, which showed the usefulness of subendocardial strain for detecting subtle rejection.
Conclusions: Strain measurement obtained by Velocity Vector Imaging, especially by using subendocardial strain, might be useful for detecting cardiac allograft rejection.