Introduction
Right ventricular (RV) function strongly predicts outcome after cardiac
surgery.1, 2 Echocardiography remains a cornerstone in
detecting perioperative RV dysfunction, but the complex geometry of the
right ventricle makes echocardiographic assessment still
challenging.3, 4 Conventional echocardiographic
parameters for RV function assessment have numerous limitations
including incomplete imaging of the complex crescent-shaped right
ventricle and angle dependency of Doppler and M-mode
technique.5 Strain analysis with speckle-tracking
echocardiography (STE) becomes an advancing technique to measure
myocardial function. Myocardial strain analysis is less dependent on
loading conditions, does not rely on geometric assumptions, has a
smaller interobserver variability, is largely angle-independent and is
an independent predictor of RV function.6-8 Therefore,
strain analysis seems particularly suitable for the perioperative
assessment of the right ventricle. Most data on RV strain analysis,
however, comes from the evaluation of awake spontaneously breathing
patients using transthoracic echocardiography (TTE).5,
9 Intraoperative evaluation of RV strain in anesthetized and ventilated
patients using transesophageal echocardiography (TEE) is feasible and
supports perioperative decision making, but there is only limited
data.7, 10 In particular, this is true for
three-dimensional derived right ventricular strain
analysis.11, 12 Regardless of the possible benefit of
three-dimensional derived RV strain, this technique is quite novel and
is not well described in the intraoperative period. Evaluation is
challenging by the fact that there are no established normal or
reference values for the intraoperative setting. Therefore, by the
present study we aim to close this gap by providing intraoperative
values for three-dimensional derived right ventricular free-wall strain
(3D-RV FWS) that can be expected in onpump coronary artery bypass
grafting (CABG) patients with a complication-free, unremarkable
intraoperative course.