The Value Of Speckle Tracking Imaging In Evaluating Ischemic Mitral Regurgitation Before And After Coronary Artery Bypass Grafting

Purpose: Analysis of cardiac changes in patients with moderate ischemic mitral regurgitation before and after coronary artery bypass grafting by two-dimensional speckle tracking technology,to understand the effect of coronary artery bypass grafting on moderate ischemic mitral regurgitation,and explore the clinical value of two-dimensional speckle tracking technology.Materials and methods: Moderate ischemic mitral regurgitation group(IMR group): We selected 35 patients with moderate ischemic mitral regurgitation diagnosed by coronary angiography and echocardiography at rest in cardiovascular surgery in our hospital from January 2019 to December 2019.Twenty patients who finally met the image requirements and completed follow-up,including 18 males,had an average age of(60.20 ± 5.83)years.Coronary heart disease group without mitral regurgitation(CHD group): We selected 26 patients with simple coronary heart disease diagnosed by coronary angiography at rest in cardiovascular surgery in our hospital from January 2019 to December 2019.Twenty patients who finally met the image requirements and completed follow-up,including 16 males,had an average age of(62.80 ± 7.21)years.Two groups of patients underwent a routine echocardiographic examination at rest.Two-dimensional echocardiographic parameters were measured under standard sections: left atrial diameter(LAD),left ventricular end diastolic diameter(LVEDD),and left ventricular end systolic volume(LVESV),Left ventricular end-diastolic volume(LVEDV),Simpson method to measure left ventricular ejection fraction(LVEF).And obtain 2D grayscale dynamic images of 6 standard sections(mitral valve,papillary muscle,apical short-axis section,and apical two-chamber,three-chamber,and four-chamber sections),the frame rate is greater than 100 frames / second,and each view records more than 3 cardiac cycles.Processing acquired images used QLAB 9.0 software CMQ program.The left ventricular wall was divided into the anterior descending branch,the circumflex branch,and the right coronary blood supply area according to the coronary blood supply area.The circumferential strain,radial strain,and longitudinal strain of the left ventricular systole in each group were analyzed and measured.Result: 1.Comparison of basic clinical data between two groups of patients The comparison of clinical data between the two groups of patients showed that only the BNP difference was statistically significant(P <0.05).2.Comparison of conventional ultrasound measurement parameters of left heart between two groups of patients Comparison between the two groups of patients before surgery: LAD,LVEDD,LVEDV,and LVESV in the IMR group were higher than those in the CHD group,and LVEF was lower than in the CHD group,and the differences were statistically significant(P <0.05).Comparison between the two groups of patients before and after CABG surgery: LAD,LVEDD,LVEDV,LVESV,and regurgitation area in the IMR group were lower than before surgery,and LVEF was higher than before surgery,and the differences were statistically significant(P <0.05).In the CHD group,only LAD and LVEDD were lower than before the operation,and the difference was statistically significant(P <0.05).3.Comparison of left ventricular myocardial segmental strain between two groups of patients based on coronary blood supply area(1)Comparison of myocardial segment strain in the anterior descending blood supply area Preoperative IMR group compared with CHD group: the differences in myocardial segments of MA,APA,BAS in circumferential strain,MAS,APS in radial strain,and MA,APA,APS in longitudinal strain were statistically significant(P <0.05).Comparison in the IMR group at 3 months after CABG: the strains increased to varying degrees,among which MA,APA,BAS,MAS in circumferential strain,MAS,APS in radial strain,MA,APA,MAS,APS in longitudinal strain showed statistically significant differences(P <0.05).(2)Comparison of myocardial segment strain in the circumflex blood supply area Preoperative IMR group compared with CHD group: the differences in myocardial segments between BAL,APL,BIL,and MIL in circumferential strain,BAL and MIL in radial strain,and BAL and APL in longitudinal strain were statistically significant(P <0.05).Comparison in the IMR group at 3 months after CABG: the strains increased to varying degrees,among which MAL in circumferential strain,MAL and MIL in radial strain,and APL,BIL,and MIL in longitudinal strain showed statistically significant differences(P <0.05).(3)Comparison of myocardial segment strain in right coronary artery blood supply area Preoperative IMR group compared with CHD group: The differences of BI,MI,and API in circumferential strain,BI in radial strain,and MI and API in longitudinal strain were statistically significant(P <0.05).Comparison within the IMR group at 3 months after CABG: the strains increased to varying degrees,among which BIS,BI,MI in circumferential strain,BIS,MIS,BI in radial strain,and BIS,BI myocardial segment differences in longitudinal strain showed statistically significant differences(P <0.05).4.The value of myocardial strain in predicting residual reflux after CABG surgery The myocardial strain was used to predict the occurrence of residual reflux after CABG by ROC curve.Left ventricular basal segment myocardial strain prediction of residual reflux: longitudinal strain cutoff value is-14.85,sensitivity and specificity are 83.3% and 78.6% respectively;circumferential strain cutoff value is-14.25,sensitivity and specificity are 66.7%,92.9%.Left ventricular middle segment myocardial strain prediction of residual reflux: longitudinal strain cutoff value is-16.00,sensitivity and specificity are 66.7% and 85.7% respectively;circumferential strain cutoff value is-14.10,sensitivity and specificity are 50.0%,92.9 %.5.Correlation analysis between preoperative two-dimensional ultrasound parameters and postoperative LVEF in patients in IMR group At 3 months after operation,LVEF in IMR group had correlation with preoperative LAD,LVEDD,LVEDV,and LVEF(r = 0.625,0.707,0.739,0.499),and had stronger correlation with LVEDD and LVEDV(P <0.01).However,compared with the conventional ultrasound parameters of patients with residual reflux in the IMR group and those with improved reflux,the difference between the two groups was not statistically significant(P> 0.05).Conclusion: 1.The two-dimensional speckle tracking technology can find the left ventricular segment’s functional impairment status and degree in patients with moderate ischemic mitral regurgitation,and provide a more reliable basis for the selection of clinical intervention treatment schemes,helping to further clarify the pathogenesis of IMR mechanism.2.Two-dimensional speckle tracking technology combined with preoperative two-dimensional conventional ultrasound parameters LVEDD,LVEDV,and LVEF can better predict the recovery of left ventricular function and mitral regurgitation in patients after surgery,and provide risk stratified data for clinical use.3.Coronary artery bypass grafting can improve partial moderate ischemic mitral regurgitation.The use of two-dimensional speckle tracking technology can provide a reference for predicting residual regurgitation after surgery,and the progress of left ventricular myocardial blood supply recovery can be observed during postoperative follow-up.