| Coronary artery atherosclerotic heart disease(CHD)is a common cardiovascular disease,with increased prevalence and mortality rate,and the acceleration of population aging and widespread prevalence of risk factors make it possible to continue to rise in the next 5 years.Coronary artery bypass grafting(CABG)is an effective common revascularization treatment for severe coronary artery disease to reduce the risk of sudden cardiac death and improve myocardial function.This operation was primarily conducted with using of cardiopulmonary bypass(on-pump CABG),providing convenient way to access accurate coronary anastomosis in good version on the arrested heart.Performing CABG on the bearing heart(off-pump CABG)is less invasive approach,along with less complications caused by cardiopulmonary bypass(CPB)and manipulation of the aorta.Previous studies have shown postoperative serum myocardial enzymes levels were lower in the off-pump CABG than the on-pump CABG group,suggesting reduction in the degree of myocardial necrosis without CPB early after surgery.Some other studies have reported off-pump CABG was associated with higher long-term risk of death,increased risk of incomplete revascularization and rates of repeat revascularization than on-pump CABG.The question of whether on-pump CABG or off-pump CABG offers better myocardial function early and late after surgery,remains controversial and requires further investigations.The strategy for evaluation preoperative heart function and myocardial function recovery at early and late after revascularization is critically important for patients underwent CABG.Magnetic resonance imaging is considered a standard technique for this purpose and can accurately investigate mechanical characteristics of myocardial deformation.However,The nature of high cost and timing-consuming limits wide use.Echocardiography is a novel,inexpensive and noninvasive modality to assess global and regional myocardial function.Speckle tracking echocardiography(STE)is based on echocardiography and developed to calculate the speed,displacement of selected region to calculate myocardial tissue motion,with less dependent on geometric assumptions and loading conditions than conventional echocardiographic parameters.Several studies have shown left ventricular global longitudinal strain(LVGLS)was more sensitive than LV ejection fraction(LVEF)to earlier find minor myocardial damage,and an independent predictor of cardiovascular outcomes.Therefore,this study aimed to using echocardiography and strain measurements to investigate the effect of on-pump versus off-pump CABG surgery on perioperative and postoperative myocardial function.Part Ⅰ.Speckle-Tracking Echocardiography to monitor the effect of on-pump versus off-pump coronary artery bypass grafting on myocardial structure and function on perioperative periodObjective:CABG is an effective common revascularization treatment performed worldwide for severe coronary artery disease,with using CPB or not.The strategies of on-pump or off-pump CABG are still debatable and have been compared in many clinical trials,using different methods and emphasizing on specific parameters.This study aims to compare the myocardial function between on-pump and off-pump CABG during perioperative period.Methods:This study enrolled 625 patients underwent elective isolated CABG between December 2019 and January 2021,by means of echocardiography and strain measurements,to investigate the effects of the revascularization treatment with both on-pump and off-pump techniques on myocardial function and monitor changes on myocardial function after selective isolated CABG surgery during perioperative period.Results:The mean age of the total study population was 61.50±8.88 years and 79.36%were men,divided into the on-pump CABG group(n=366,58.56%)and the off-pump CABG group(n=259,41.44%).There were no statistically significant differences between two groups,except for body surface area,heart rate,New York Heart Association(NYHA)functional classification and serum troponin I(cTn I).The onpump CABG group had more grafts(3.37±0.80 vs 3.17±0.91,P=0.006).Preoperative echocardiographic parameters and strain measurements were similar between two groups,the mean LVEF was 58.83 ± 9.24%in on-pump group and 59.74±8.75%in off-pump group.After surgery,LVEF in off-pump group decreased to 57.84±8.06%(P<0.05),while the decline in on-pump group was not statistical difference.The volumetric parameters(LVEDVI,SVI,LAVI),size parameters(LVEDDI,LAD,RVD)and LVMI decreased significantly in both groups(P<0.05)early after surgery.Meanwhile,all strain measurements in both groups were lower than its preoperative level(P<0.05).In addition,LVEDVI,LVEDDI and LVESDI were higher in off-pump group,compared with on-pump group(P<0.05).Conclusions:The decline in myocardial function occurs early after on-pump or offpump CABG,and the recovery of global and regional functions still requires follow-up studies.Part Ⅱ.Speckle-Tracking Echocardiography to monitor the effect of on-pump versus off-pump coronary artery bypass grafting on myocardial structure and function by 3-month follow-upObjective:This study aims to compare the myocardial function between on-pump and off-pump CABG at short-term follow-up(3 months).Methods:This study used echocardiography and strain measurements to investigate the effects of the revascularization treatment with both on-pump and off-pump techniques on myocardial function and monitor changes on myocardial function after selective isolated CABG surgery at short-term follow-up(3 months).Results:Patients was divided into the on-pump CABG group(n=296,58.27%)and the off-pump CABG group(n=212,41.73%).The mean LVEF and LVGLS were respectively 58.87±7.75%and-12.47±4.55%,which increased in both groups by 3 months.The volumetric parameters(SVI),size parameters(LVEDDI,LAD)and strain measurements(LASr,LAScd,LASct,RVGLS,RVFWS)increased in both groups at short-term follow-up,compared with the early postoperative level(P<0.05).In addition,LAScd,LASct,RVFWS and RVGLS were higher in the on-pump group than off-pump group,while LAVI was lower in the on-pump group(P<0.05).Conclusions:The decline in myocardial function occurs early after on-pump or offpump CABG,and relatively reversible at 3 months.The recovery of left atrial function was earlier in the on-pump than off-pump CABG group.While both groups have different levels of right ventricular dysfunction and still need the follow-up observations.Part Ⅲ.Speckle-Tracking Echocardiography to monitor the effect of on-pump versus off-pump coronary artery bypass grafting on myocardial structure and function by 1-year follow-upObjective:This study aims to compare the myocardial function between on-pump CABG and off-pump CABG by 1-year follow-up.Methods:This study used echocardiography and strain measurements to investigate the effects of the revascularization treatment with both on-pump and off-pump techniques on myocardial function and monitor changes on myocardial function after selective isolated CABG surgery at 1-year after surgery.Results:The study cohorts were divided into the on-pump group(n=245,56.84%)and the off-pump group(n=186,43.16%).The mean LVEF and LVGLS were respectively 58.90±8.28%and-12.70±4.19%,which were similar with its level at 3 months.The LV remodeling index decreased in both groups compared with its preoperative levels(P<0.05),while the decline of LVMI only in the on-pump CABG group showed statistical significance(P<0.05).The LASr and LASct in the off-pump CABG group were similar with its preoperative level.In addition,there are no significant intergroup difference regarding RVFWS and RVGLS,both significantly lower than preoperative level by 1 year follow-up(P<0.05).Conclusions:Right ventricular dysfunction occurred early after surgery and remains up to 1 year,which was independent of the surgical technique. |
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