Patient Consensus Statement
All patients were enrolled between January 2019 and April 2020 after
written informed consent.
Objectives: Data on intraoperative three-dimensional derived
right ventricular free-wall strain (3D-RV FWS) is sparse. We sought to
evaluate the normal range of intraoperative 3D-RV FWS in patients
scheduled for coronary artery bypass graft (CABG) surgery and compare to
conventional echocardiographic parameters.
Design: Prospective observational study.
Setting: Single university hospital.
Participants: 150 patients with preserved left and right
ventricular function and sinus rhythm, without significant heart valve
disease or pulmonary hypertension undergoing isolated onpump CABG
surgery, with an uneventful, complication-free intraoperative course.
Interventions: 3D-RV FWS analysis and conventional
echocardiographic assessment of right ventricular function were
performed intraoperatively in anesthetized and ventilated patients using
transesophageal echocardiography (TEE). All echocardiographic
measurements were performed under stable hemodynamic conditions and
predefined fluid management without any vasoactive support or pacing.
Measurements and Main Results: We used TomTec 4D RV-Function 2.0
software for assessment of 3D-RV FWS and three-dimensional right
ventricular ejection fraction (3D-RV EF). Philips QLAB 10.8 was used to
evaluate tissue velocity of the tricuspid annulus (RV S´), tricuspid
annular systolic excursion (TAPSE), and RV fractional area change (FAC).
Assessment of 3D-RV FWS was feasible in 95% of patients. No included
patient experienced a serious perioperative complication.
In our group of patients, median values with interquartile range (IQR)
for 3D-RV FWS and 3D-RV EF were - 25.2 (IQR -29.9 - -21.8) and 46.3%
(IQR 41.0 - 50.1%), respectively. RV FAC, RV S´ and TAPSE accounted for
39.7% (IQR 34.5 - 44.4%), 14.8cm/s (IQR 11.8 - 19.0cm/s) and 22 mm
(IQR 20-25mm). Normal range (2.5% to 97.5% percentile) for 3D-RV FWS
was -37.1 to -12.8.
There was no relevant correlation of 3D-RV FWS to postoperative outcome
in this group of CABG patients.
Conclusion: We present distribution values for intraoperative
3D-RV FWS and conventional parameters of RV function assessment in a
healthy on-pump CABG patient population without serious perioperative
complications. We observed no correlations of these parameters with any
of the outcome parameters considered. Therefore, we consider these
values to be intraoperative TEE-assessed normal values that can
be expected in onpump CABG patients.
Key Words: three-dimensional echocardiography; strain analysis;
right ventricle; free wall strain; cardiac surgery; reference values