Quantitative evaluation of left ventricular myocardial work by pressure-strain loops using echocardiography in patients undergoing coronary artery bypass grafting

Objective To quantitatively evaluate the changes of left ventricular myocardial work indices by pressure-strain loops (PSL) using echocardiography in patients undergoing coronary artery bypass grafting (CABG). Methods Thirty patients undergoing CABG from October 2018 to May 2019 in Henan Provincial People′s Hospital were chosen as the case group, and 30 healthy subjects were selected as the control group. The myocardial work indices of left ventricle, including global work index (GWI), global constructive work (GCW), global work waste (GWW) and global work efficiency (GWE) were measured by PSL, the differences in myocardial work indices between the two groups, including controls, patients before surgery, 1 month, and 3 months after CABG were compared. Results Compared with the control group, GWI, GCW, GWE of the left ventricle in each case groups were decreased before and after CABG, while GWW was increased significantly(all P 0.05), while GWI, GWE of left ventricle of the postoperative 3-month were increased, and the differences were statistically significant (all P<0.05); the differences of GWI, GCW, GWE between the postoperative 1-month and 3-month were statistically significant (all P<0.05). GWI, GCW, GWW, GWE were significantly related to left ventricular ejection fraction (LVEF) or global longitudinal strain (GLS) (all P=0.00). Bland-Altman drawing plots showed that the measurements of GWI, GCW, GWW, GWE between the observers and within the same observer exhibited good reproducibility. Conclusions PSL can quantitatively evaluate left ventricular myocardial work and provide a new method for the evaluation of left ventricular systolic function in patients undergoing CABG. Key words: Echocardiography; Coronary heart disease; Coronary artery bypass grafting; Myocardial work; Left ventricular systolic function