| Objective To discuss the value of hibernating myocardium quantitatively detected by positron emission tomography/X-ray computed tomography（PET/CT）in predicting the improvement of left ventricular ejection fraction（LVEF）and major adverse events（MACE）rates after coronary artery bypass grafting（CABG）in patients with coronary heart disease.And we also comparatively analyze the difference between visual method and software program in calculating different types of myocardium and to evaluate the correlation and consistency of these two methods for PET/CT myocardial perfusion and metabolic imaging.Methods Total 46 patients whose LVEF were severely reduced（≤40%）received 13N-ammonia（NH3）/18F-fluorodeoxyglucose（FDG）PET/CT and Echocardiography before CABG.Echocardiography was conducted again 332 months after CABG to analyze the improvement of LVEF and the MACE was evaluated as well.Other 51 patients whose LVEF were severely reduced（≤40%）then received 13N-ammonia（NH3）/18F-fluorodeoxyglucose（FDG）PET/CT to evaluate the number of normal myocardium,hibernating myocardium and scar myocardium semi-quantitatively measured by visual method and ECToolbox software.The number of hibernating myocardium was divided into three groups according to the result of visual method.Group1:the number of hibernating myocardium was less than 10%;Group2:the number of hibernating myocardium was more than 10%but less than 20%;Group3:the number of hibernating myocardium was more than 20%.The number of hibernating myocardium evaluated by different methods in each group was then differentiated.Results The LVEF improved group has more hibernating myocardium,less scar myocardium and smaller left ventricular end-systolic volume than that of LVEF non-improved group.Moreover,the number of hibernating myocardium and LVESV are the independent factors for predicting LVEF improvement.In addition,the optimal threshold value for the number of hibernating myocardium in predicting LVEF improvement was 21%.Furthemore,the factor associated with the occurrence of early MACE is severe mitral regurgitation.The number of hibernating myocardium and normal myocardium calculated by software was higher than that by visual method,and there was no significant difference in the number of scar myocardium（P>0.05）.A positive correlation for hibernating myocardium（r=0.767）and normal myocardium（r=0.478）was found between visual method and software.Bland-Altman curve indicated that the number of hibernating myocardium and normal myocardium evaluated by these two methods is inconsistent except for the number of scar myocardium.Hibernation subgroup analysis:the number of hibernating myocardium evaluated by visual method is higher than that evaluated by software（2.6±3.6 vs 10.2±6.2,P=0.000）.There was no significant difference in the number of hibernating myocardium between Group 2（P=0.064）and Group3（P=0.299）.Conclusion Patients whose number of hibernating myocardium is more than 21%can be benefit from CABG.Patients with severe mitral regurgitation are more likely to develop early MACE.The number of hibernating myocardium assessed by PET myocardial flow-metabolic imaging is a effective predictor for LVEF improvement after CABG.Visual method correlates well with software program in assessing scar myocardium.The number of hibernating myocardium evaluated by software is higher than that by visual method.Visual method will underestimate the number of hibernating myocardium,but with the range of mismatch（hibernating myocardium）increases,the difference tends to be smaller. |
