Evaluation on the impact of spontaneous reperfusion on cardiac muscle of acute myocardial infarction by three-dimensional speckle tracking imaging.

OBJECTIVE: To explore the effect of spontaneous reperfusion (SR) on three-dimensional myocardial strain in patients with acute anterior myocardial infarction by three-dimensional speckle tracking imaging (3D-STI) technology. PATIENTS AND METHODS: Patients diagnosed with acute anterior myocardial infarction during 2013 to 2016 were consecutively selected and divided into SR group and non-spontaneous reperfusion (Non-SR) group based on whether there was SR. Patients in both groups received direct percutaneous coronary intervention (PCI) in time window. Baseline information, patency rates of culprit vessel, durations of operation, intraoperative non-reflow phenomenon ratios, and thrombolysis in myocardial infarction (TIMI) blood flows after reperfusion of patients in each group were recorded. Hospital stays of patients were compared between the two groups. Before discharge, left ventricular ejection fraction (LVEF) and left ventricular end-diastolic diameter (LVEDd) were measured. Global longitudinal strain (GLS), global radial strain (GRS), and global circumferential strain (GCS) of left ventricular (LV) were also detected by 3D-STI, so as to assess movement situations of ventricular wall and cardiac muscle in occlusive blood vessel distribution area. LVEF, LVEDd and various 3D-STI parameters were reexamined and compared one year after discharge. RESULTS: There were no significant differences between the Non-SR group and the SR group regarding the patency rate of culprit vessel, duration of operation, intraoperative non-reflow phenomenon ratio, TIMI blood flow after reperfusion, and LVEDd (p>0.05). Both LVEF before discharge and LV three-dimensional strain indexes of the SR group, were clearly higher than those of the Non-SR group (p<0.05). After one-year follow-up, the SR group had a remarkably lower LVEDd than the Non-SR group (p<0.05). LVEF of the SR group was overtly higher than that of the Non-SR group (p<0.05). LV three-dimensional strain indexes were also distinctly higher in the SR group than in the Non-SR group (p<0.05). There were good correlations between GLS, GRS, GCS and LVEF (r values were -0.620, -0.674 and 0.723, respectively). CONCLUSIONS: SR can improve nosocomial and long-term LV remodeling in patients with acute anterior myocardial infarction, and 3D-STI is able to assess ventricular remodeling after myocardial infarction.

[Relationship between myocardial microRNA-30a expression and myocardial fibrosis in rats post myocardial infarction].

OBJECTIVE: To explore the potential role and mechanism of microRNA(miR)-30a in myocardial fibrosis after myocardial infarction (MI). METHODS: Rats were randomly divided into 1 week MI group (n=11), 2 weeks MI group (n=13) and 4 weeks MI group (n=15) by applying random number table after left anterior descending coronary artery ligation. Rats in Sham group were examined at respective time points (n=16). Heart function was monitored by echocardiography. Myocardial collagen volume fraction (CVF) was determined on Masson stained sections. Myocardial expression of collagen Ⅰ and Ⅲ was determined by immunohistochemistry. The myocardial mRNA level of miR-30a, TGF-ß1 and CTGF were detected by real time-quantitative PCR analysis. The myocardial protein levels of TGF-ß1 and CTGF were measured by Western blot analysis. RESULTS: The LVEDD ((8.37±0.58) mm) and LVESD ((6.12±0.82) mm) in 4 weeks MI group were significantly higher than those in Sham group ((6.08±0.57) mm, (4.17±0.60) mm), all P<0.01. The FS ((27.0±3.9) %) and LVEF ((51.0±6.3) %) in 4 weeks MI group were significantly lower than those in Sham group ((47.0±2.1) %, (82.0±2.3)%), all P<0.01. The level of myocardial CVF in 1 week MI group, 2 weeks MI group and 4 weeks MI group were significantly higher than in Sham group (all P<0.01) in a time-dependent manner. The level of myocardial collagen Ⅰ and Ⅲ was increased gradually from 1 week to 4 weeks post MI compared with Sham group (all P<0.01). The collagen Ⅰ/Ⅲ ratio was similar between 1 week MI group and Sham group (P=0.58), however, which was significantly higher in 2 weeks MI group and 4 weeks MI group compared with Sham group (all P<0.01), and the ratio was significantly higher in 4 weeks MI group than 2 weeks MI group (P<0.01). The level of miR-30a was significantly and gradually reduced in all MI groups compared with Sham group (all P<0.01). The mRNA and protein levels of TGF-ß1 and CTGF were significantly and gradually increased after MI compared with Sham group (all P<0.001). CONCLUSIONS: Our results indicate that overexpression of miR-30a after MI might be a potential strategy for suppressing myocardial fibrosis by modulating the mRNA and protein levels of TGF-ß1 and CTGF.

Cobalt chromium-based biodegradable polymer sirolimus-eluting stent: rationale, evidence and clinical experience.

Metallic drug-eluting stents (DES) are the first choice for percutaneous coronary interventional treatment of coronary artery disease at present. Although they have overcome some disadvantages and limitations of plain balloon angioplasty and bare-metal stents, chronic local inflammatory reactions related to permanent polymer existence and poor vascular healing after first generation DES implantation may translate into the increased risk of late and very late stent thrombosis. There have been technological developments in stent design, materials and coatings, including more conformable platform designs, biocompatible or biodegradable polymers and improved kinetics of drug release. The newer generation DES have proven superior to previous DES technology in terms of both safety and efficacy. Accumulating evidence has suggested that DES with cobalt chromium stent platform, modified biodegradable polymer coatings, and rapamycin derivative drugs are associated with improved clinical outcomes. Currently, several new cobalt chromium biodegradable polymer sirolimus-eluting stents have been introduced to clinical practice. This review will describe basic concept and rationale behind the newer cobalt chromium biodegradable polymer sirolimus-eluting stents, systematically present the new clinical experiences with several representative devices.