Ultrasonic strain/strain rate imaging--a new clinical tool to evaluate the transplanted heart

The aim of this study was to investigate the clinical applicability of strain and strain rate imaging (epsilon/SRI) in heart transplantation (Htx) patients and to establish "normal" post-Htx regional systolic deformation values.

Epsilon/SR indices have been shown to be a more sensitive measure of regional systolic function than standard echo measurements. Thus, they might provide a new tool to better define both normal cardiac graft function and detect changes due to post-Htx complications. However, prior to investigating the role of epsilon/SRI in detecting abnormalities, "normal" post-Htx regional deformation values must be established as graft regional function can be altered by a number of factors such as ischemic time, surgical technique or accelerated graft ageing.

A total of 57 Htx patients (age 36+/-12 years; post-Htx 5.5+/-3 years) without any documented complication were studied. Epsilon/SRI data were acquired from the septum, left ventricular (LV) free walls and right ventricular free wall (RVFW). A total of 29 age-matched healthy subjects served as controls.

Htx longitudinal peak systolic velocities (Vsys) were lower in inferior, septal and RVFW segments compared to controls. Peak systolic epsilon/SR (epsilonsys/SRsys)) did not differ from controls except in septum and RVFW in which the values were significantly reduced. Radial Vsys) in the Htx group were higher than controls while epsilonsys/SRsys were reduced. There was a significant decrease in SR(sys) in apical LV segments with increasing time post-Htx, whereas those measured in RVFW showed an increase by that time.

Epsilon/SRI demonstrated that "healthy" Htx hearts have normal global systolic function but altered regional systolic deformation indices compared to normal hearts. Post-Htx time has a diminishing effect on the regional systolic deformation indices in LV segments but an improving effect in RVFW. These "normal" Htx values should provide the basis for subsequent studies into the role of epsilon/SRI in the non-invasive detection of post-Htx complications.