ABSTRACT
Objective:To explore the prognostic predictive value of deep neural network (DNN) assisted myocardial contrast echocardiography (MCE) quantitative analysis of ST-elevated myocardial infarction (STEMI) patients after successful percutaneous coronary intervention(PCI).Methods:A retrospective analysis was performed in 97 STEMI patients with thrombolysis in myocardial infarction-3 flow in infarct vessel after primary PCI in Renmin Hospital of Wuhan University from June to November 2021. MCE was performed within 48 h after PCI. Patients were followed up to 120 days. The adverse events were defined as cardiac death, hospitalization for congestive heart failure, reinfarction, stroke and recurrent angina. The framework consisted of the U-net and hierarchical convolutional LSTMs. The plateau myocardial contrast intensity (A), micro-bubble rate constant (β), and microvascular blood flow (MBF) for all myocardial segments were obtained by the framework, and then underwent variability analysis. Patients were divided into low MBF group and high MBF group based on MBF values, the baseline characteristics and adverse events were compared between the two groups. Other variables included biomarkers, ventricular wall motion analysis, MCE qualitative analysis, and left ventricular ejection fraction. The relationship between various variables and prognosis was investigated using Cox regression analysis. The ROC curve was plotted to evaluate the diagnostic efficacy of the models, and the diagnostic efficacy of the models was compared using the integrated discrimination improvement index (IDI).Results:The time-cost for processing all 3 810 frames from 97 patients was 377 s. 92.89% and 7.11% of the frames were evaluated by an experienced echocardiographer as "good segmentation" and "correction needed". The correlation coefficients of A, β, and MBF ranged from 0.97 to 0.99 for intra-observer and inter-observer variability. During follow-up, 20 patients met the adverse events. Multivariate Cox regression analysis showed that for each increase of 1 IU/s in MBF of the infarct-related artery territory, the risk of adverse events decreased by 6% ( HR 0.94, 95% CI =0.91-0.98). There was a 4.5-fold increased risk of adverse events in the low MBF group ( HR 5.50, 95% CI=1.55-19.49). After incorporating DNN-assisted MCE quantitative analysis into qualitative analysis, the IDI for prognostic prediction was 15% (AUC 0.86, sensitivity 0.78, specificity 0.73). Conclusions:MBF of the area supplied by infarct-related artery after STEMI-PCI is an independent protective factor for short-term prognosis. The DNN-assisted MCE quantitative analysis is an objective, efficient, and reproducible method to evaluate microvascular perfusion. Assessment of culprit-MBF after PCI in STEMI patients adds independent short-term prognostic information over qualitative analysis.It has the potential to be a valuable tool for risk stratification and clinical follow-up.
ABSTRACT
Objective:To investigate the diagnostic value of postsystolic shortening (PSS) and early systolic lengthening (ESL) on myocardial microvascular dysfunction in patients with ST-segment elevation myocardial infarction (STEMI) after percutaneous coronary intervention (PCI).Methods:A total of 83 patients with STEMI who received emergency PCI in Renmin Hospital of Wuhan University from June to October 2021 were retrospectively collected. All patiets underwent two-dimensional echocardiography and myocardial contrast echocardiography (MCE) within 7 days after PCI. The patients were divided into global normal perfusion group and poor perfusion group according to global myocardial perfusion score index (MPSI). Left ventricular myocardium was divided into left anterior descending branch (LAD), left circumflex branch (LCx) and right coronary artery (RCA) regions, which were divided into regional normal perfusion group and poor perfusion group based on whether there were segments with microvascular dysfunction. Left ventricular end-systolic volume (LVESV) and left ventricular ejection fraction (LVEF) were measured by modified biplane Simpson method. Tomtec software was used to obtain conventional echocardiographic parameters, global longitudinal strain (GLS), as well as PSS and ESL parameters including postsystolic index (PSI), duration of postsystolic shortening (PSSduration), early systolic index (ESI) and duration of early systolic lengthening (ESLduration). Differences of parameters of global normal and poor perfusion groups, as well as regional normal and poor perfusion groups were compared. ROC curve was used to analyze the diagnostic value of PSS and ESL parameters and GLS in myocardial regions with microvascular dysfunction.Results:Significant differences were observed in LVEF, LVESV, GLS, PSI, ESI and PSSduration between global poor perfusion group and global normal perfusion group (all P<0.05). Compared with regional normal perfusion group, PSI, ESI and ESLduration of LAD and LCx regions, as well as PSI of RCA region in regional poor perfusion group were increased (all P<0.05). For GLS in different myocardial regions, LAD-GLS was the only parameter that decreased in regional poor perfusion group compared to regional normal perfusion group ( P<0.05). ROC curve analysis showed LAD-PSI, LAD-GLS, LCx-PSI, LCx-ESLduration and RCA-PSI were valuable parameters for diagnosis of myocardial microvascular dysfunction in different regions, among which LAD-PSI had the highest area under curve (AUC=0.809). Conclusions:PSS and ESL parameters are helpful for early diagnosis of myocardial microvascular dysfunction in STEMI patients after PCI, and can provide regional myocardial perfusion information according to the blood supply of different coronary arteries.