Perioperative Two-Dimensional Left Ventricular Global Longitudinal Strain in Coronary Artery Bypass Surgery: A Prospective Observational Pilot Study

Abstract

There are limited data on perioperative left ventricular strain. The authors aimed to describe the entire perioperative course of two-dimensional left ventricular global longitudinal strain in patients undergoing coronary artery bypass graft (CABG) surgery and compare to common parameters of LV function assessment. Prospective observational study. Single university hospital. Forty patients scheduled for isolated on-pump CABG surgery with preserved left and right ventricular function with an unremarkable, complication-free perioperative course. Two-dimensional strain analysis and standard echocardiographic assessment of left ventricular function were performed pre- (T1) and postoperatively (T4) by transthoracic echocardiography (TTE) and intraoperatively pre- (T2) and poststernotomy (T3) by transesophageal echocardiography (TEE). Echocardiography was performed under stable hemodynamics and predefined fluid management, in sinus rhythm without any vasoactive support. Analysis of two-dimensional LV global longitudinal strain (2D-LV GLS) was performed using Tomtec 2D Cardiac Performance Analysis software. Philips QLAB 10.8 was used to analyze left ventricular ejection fraction (LV EF) and tissue velocity of the lateral mitral annulus (LV S ́). There were no significant differences (median with interquartile range [IQR]) after induction of anesthesia in values of LV EF and 2D-LV GLS (T1 v T2; 59% [IQR, 52 to 64] v 56% [IQR, 51.75 to 63] and -15.2 [IQR, -18.05 to -13.08] v -15.6 [IQR, -17.65 to -13.88]; both not significant [ns]), while LV S´ declined (T1 v T2, 7 cm/s [IQR, 5.25 to 8] v 5.25 cm/s [IQR, 4.6 to 6.83]; p < 0.001). Bland-Altman analysis for this comparison of 2D-LV GLS (T1 v T2) showed that bias was not significant between both techniques; however, there were limits of agreement. After sternotomy (T2 v T3) neither LV EF nor 2D-LV GLS or LV S´ declined. 2D-LV GLS deteriorated significantly after CABG (T1 v T4; -15.2 [IQR, -18.05 to -13.08] v -11.3 [IQR, -15.8 to -9.78]; p < 0.001). In contrast, LV EF and LV S´ did not change significantly in the perioperative interval (T1 v T4; 59% [IQR, 52 to 64] v 56% [IQR, 51.5 to 64.25] and 7 cm/s [IQR, 5.25 to 8] v 7 cm/s [IQR, 6 to 8]; both ns). Values of 2D-LV GLS did not differ in awake, spontaneously breathing patients assessed by TTE and in anesthetized and ventilated patients with stable hemodynamics measured by TEE. 2D-LV GLS did not change after sternotomy; however, it declined significantly after on-pump CABG, while LV EF and LV S´ remained unchanged.