Evaluation Of Microcirculation Perfusion And Left Ventricular Function After Percutaneous Coronary Intervention In Patients With Chronic Total Occlusion By Myocardial Contrast Echocardiography Combined With Speckle Tracking Technique

Objective:To investigate the value of myocardial contrast echocardiography（MCE）combined with two-dimensional speckle tracking technology（2D-STE）in evaluating myocardial microcirculation perfusion and left ventricular function in patients with chronic total occlusion（CTO）after percutaneous coronary intervention（PCI）.Methods:A total of 31 CTO patients（60.90±10.67 years）were enrolled in the people’s Hospital of Liaoning Province from September 2017 to December 2020.Transthoracic echocardiography,2D-STE and MCE were performed before PCI,and after 3-day and 6-months of procedure.The standard section image of the cardiac is routinely stored in the basic state,the early diastolic blood flow velocity（E peak）,late diastolic flow velocity（A peak）,early diastolic velocity of interventricular septum of mitral annulus（e _S’）,early diastolic velocity of lateral wall of mitral annulus（e _L’）,left ventricular end diastolic volume（LVEDV）,left ventricular end systolic volume（LVESV）and left ventricular ejection fraction（LVEF）were measured,and E/A and E/e’were calculated based on the data.2D-STE uses the built-in automatic functional imaging analysis software to obtain the total longitudinal strain（GLS）and regional longitudinal strain（RLS）of the left ventricle.Semi-quantitative analysis of MCE was performed using the following criteria that uniform and sufficient contrast agent display and good perfusion is 1 point,sparse contrast agent display and weak perfusion or partial and flaky perfusion is 2 point,and contrast agent filling defect or no perfusion is 3 point.The semi-quantitative index was statistically analyzed using the contrast-enhanced index（CSI）,which is calculated by dividing the sum of the relevant segmental angiographic scores by the number of segments.When quantitative analysis is performed in in the mode of MCE,the QLAB quantification software auto-matically generates the time-perfusion intensity curve and fits the function Y=Ax(1-e^βt)+C,where A is the peak intensity of the curve,reflecting the myocardial blood volume,βis the slope of the curve,reflecting the myocardial blood flow velocity and Axβreflects the myocardial blood flow（MBF）.The average values of regional myocardial perfusion parameters A,βand MBF were calculated according to the range of left anterior descending（LAD）,right coronary artery（RCA）and left circumflex artery（LCX）of the three main coronary vessels.The changes of parameters were compared before operation,3 days and 6 months after PCI.Results:1.Compared with before PCI,there was no statistically significant difference in the improvement of LA,E/A,e’,E/e’,LVEDV,LVESV and LVEF in CTO-PCI patients after 3-days and 6-months of procedure（P>0.05）;Compared with preoperatively,GLS and RLS was improved after 3-day and 6-months of procedure,the difference is obvious and statistically significant（P<0.05）;Compared with 3-days after treatment,GLS and RLS improved more significantly 6-months after PCI（P<0.05）.2.Compared with preoperatively,the left ventricular regional myocardial blood perfusion parameters CSI,A,βand MBF gradually increased at 3-days and 6-months after PCI,and the difference is obvious and statistically significant（P<0.05）;Compared with 3-days after procedure,A,βand MBF improved more significantly at6-months after PCI,and the difference was statistically significant（P<0.05）.3.Pearson correlation analysis showed that the absolute value of RLS was positively correlated with A,βand MBF（r=0.76,0.56,0.68,P<0.05）.Conclusion:MCE combined with 2D-STE can sensitively and quantitatively evaluate the improvement of myocardial perfusion and cardiac function in patients with CTO after PCI,and provide objective basis for prognosis follow-up.