Right ventricular transverse displacement increases following cardiac surgery: possibly compensating loss in tricuspid annular plane systolic excursion (TAPSE)

Right Ventricular (RV) output mostly derives from longitudinal shortening in normal hearts. However, following even uncomplicated cardiac surgery with preserved RV function a significant and sustained decrease in longitudinal contraction has been observed. How the RV compensates and sustains output in this setting remains unsettled. The aim of this study was to evaluate the RV contraction pattern by speckle tracking echocardiography to elucidate possible compensatory mechanisms mitigating the reduced RV longitudinal contraction after cardiac surgery. Thirty patients with normal preoperative ejection fraction and no valvulopathy underwent coronary artery bypass grafting (CABG) with the use of cardiopulmonary bypass (CPB). RV dedicated speckle tracking software measuring longitudinal and transverse displacement, as well as strain, was employed on transesophageal echocardiographic (TEE) images as part of the Right Ventricular Echocardiography in cardiac SurgEry (ReVERSE) study. Data was recorded at baseline (after anesthesia induction), immediately after CPB and upon chest closure. Tricuspid Annulus Plane Systolic Excursion (TAPSE) was reduced from 2.0 [1.6-2.5 cm] to 0.8 [0.6-11 mm] from baseline to after chest closure. RV longitudinal displacement was reduced from 6.1 [3.4-8.8 mm] to 2.9 [0.4-5.4 mm] at the same time-points. RV speckle tracking revealed concomitantly that transverse displacement of the free wall increased significantly from 1.2 [0-2.7 mm] at baseline to 5.4 [3.6-7.2 mm] after chest closure. RV speckle tracking strain did not change significantly. Increased transverse displacement likely compensates for reduction in RV longitudinal contraction following cardiac surgery and maintains cardiac output. The sustained output from the right ventricle was not related to an increased contractility.