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Abstract

Introduction: Right ventricular (RV) dysfunction can occur after cardiac surgery. Although the exact mechanism is not well understood, it has been suggested to be associated with pericardial incision as well as other factors related to cardiac surgery. Speckle Tracking Echocardiography was performed to assess RV systolic and diastolic function before and after cardiac surgery. Methods: RV speckle tracking was performed by transthoracic echocardiography before (mean 20.4hrs ±27) and after surgery (mean 47hrs ±33) in 50 patients (mean age 67.2 years ±12, 64% male) undergoing a variety of cardiac operations: 3 coronary artery bypass grafts, 12 aortic valve replacement, 3 mitral or aortic valve mass removal, 16 open and 16 robotic-assisted minimally-invasive mitral valve repair. The following strain parameters were measured: systolic function parameters include RV free wall longitudinal strain (RV LS) and strain rate (RV LSR), and diastolic function parameter RV free wall longitudinal early strain rate relaxation (RV LSRe). Results: RV systolic function assessed by speckle tracking was significantly reduced after cardiac surgery: RV longitudinal strain -25.3% to -15.5% (p<0.001), RV longitudinal strain rate -1.5 to -0.94 (p<0.001). RV diastolic function assessed by speckle tracking was similarly reduced: RV longitudinal strain rate early relaxation 1.4 to 0.92 (p<0.001). Conventional assessment methods of RV function also showed significant reductions: TAPSE 24.7mm to 13.4mm (p<0.001), Tricuspid valve S’ 0.14m/s to 0.08m/s (p<0.001), RIMP 0.39 to 0.54 (p<0.001), RV E:e’ 4.3 to 7.2 (p<0.001). RV fractional area change, E:A ratio and RV systolic pressure estimation did not significantly change. There was no significant association for the reduction in RV systolic or diastolic function assessed by speckle tracking (RV LS, RV LSR, RV LSRe) with echo-based RV peak systolic pulmonary artery pressures, cross clamp or bypass time, time to extubation, vasoactive requirement or number of days in hospital. The association between the reduction in RV longitudinal strain and whether surgery was minimally invasive approached significance (p=0.055), with minimally invasive surgery having a smaller reduction in strain values. Conclusions: RV systolic and diastolic function decreases significantly after cardiac surgery. This reduction is independent of echo-based RV peak systolic artery pressure estimation, cross-clamp or bypass time, vasoactive requirements, intubation time or number of days in hospital. RV longitudinal strain reduction may be smaller if surgery is minimally invasive supporting the concept that RV dysfunction is associated with the size of pericardial incision. Larger studies are warranted to extend this finding.