Assessment Of Themyocardial Perfusion And Its Application In STEMI Patients

Objective: To investigate the methods of myocardial perfusion assessment in STEMI patients and verify these methods' predictive value in myocardial systolic function and short-term prognosis.We also investigated a pivotal nuclear receptor as a novel potential therapeutic target for ameliorating myocardial perfusion.Contents:Based on the new thechnique of myocardial perfusion assessment-TIMI myocardial perfusion frame count(TMPFC),we performed cardiovascular magnetic resonance(CMR)to verify that frame counting can improve the accuracy of TIMI myocardial perfusion grade(TMPG)for microvascular dysfunction(MVD);we explored the significance of different ST-segment changes early before and after percutaneous coronary intervention(PCI),in relation to CMR verified MVD;we also investigated the impact of microvascular dysfunction assessed by angiography and ST-segment changes on myocardial deformation assessed by two-dimensional speckle-tracking echocardiography(2D STE);then we investigate the effect of ROR? on the activation of monocytes and myocardial perfusion;finally,we performed a meta-analysis to investigate the relationship between plaque composition assessed by virtualhistology-intravascular ultrasound(VH-IVUS)and MVD.Method: Patients were eligible for enrolment if they had a STEMI treated with reperfusion therapy within 12 hours from onset of symptoms to PCI time.All angiographic assessmentswere based on a special angiogramperformedright after PCI.ST-segment changes in EKG parameters were assessed both on admission and 60 minutes after PCI.The presence of microvascular obstruction(MVO)and intramyocardial hemorrhage(IMH)were assessed by CMR.Peripheral blood mononuclear cell(PBMC)were isolated from whole blood by Ficoll density gradient centrifugation.Results: We use CMR to verify that frame counting can improve the accuracy of TMPG for MVD.TIMI myocardial perfusion frame count(TMPFC)is correlated with the degree of MVD and cardiac detriments,which is useful for risk stratification.Receiver operator characteristics curve analysis proposed the value of 95 frames was the optimal cutoff point to predict MVD.Using this cutoff value,the presence of MVD in infarcted tissue relates toreduced global and regional myocardial deformation.In STEMI patients,the presence of MVO and IMH in infarcted tissue was related to ST-segment changes.Maximal STE was a powerful independent predictor of presence of MVO and IMH,while sum STE was a strong correlate of the number of MVO and IMH segments.ST-segment resolution correlated with global and regional LV function and deformation in patients withsub-acute phase of STEMI after PCI.We also found that CD14++CD16-monocytes level was higher in patients with impaired myocardial perfusion.The endogenous ROR?expression was detected in human monocytes,and the expression level of ROR? was associated with myocardial perfusion level.Meta-analysis showed that plaque components were closely related to the MVD after PCI,especially the absolute volume of necrotic core and dense calcium.Conclusions:The methods of myocardial perfusion assessment correlated with eachother.TMPFC is an optimal method for MVD prediction.ROR? expression was associated with myocardial perfusion level.ROR?represents a potential therapeutic target for the improvement of myocardial perfusion.