Echocardiographic Assessment
A standard TEE probe (TEV5Ms Transducer) and echocardiography system
(Acuson SC2000, Siemens, Mountain View, CA) were used to perform a
comprehensive epicardial echocardiographic examination. In order to
allow for an optimal interface between the donor heart and the probes, a
custom-made 3D-printed spacer was applied at the tip of the transducer
and filled with gel. The probe was covered by a disposable sterile
plastic cover bag. Figure 1B illustrates the custom-made 3D-printed
spacer and figure 1C depicts the experimental timeline. The following
standard echocardiography views were obtained: apical 4 chamber (Ap4),
apical 2 chamber (Ap2), apical 3 chamber (Ap3), apical 5 chamber (Ap5),
LV short axis (LV SAX) and LV long axis (LAX). LV function was
quantified according to current
guidelines25using biplane ejection fraction (EF), fractional shorting (FS),
fractional area change (FAC), global longitudinal strain (GLS), global
circumferential strain (GCS) and radial strain (RAD). Strain was
measured off line with Echo Insight software (Epsilon Imaging,
trademark, Ann Arbor, Michigan, USA). Global strain was computed as the
average of the strain values of all LV segments. FS, FAC, GCS and RAD
were measured in the LV SAX.