Computational fluid dynamic simulations of image-based stented coronary bifurcation models

One of the relevant phenomenon associated with in-stent restenosis in coronary arteries is an altered haemodynamics in the stented region. Computational fluid dynamics (CFD) offers the possibility to investigate the haemodynamics at a level of detail not always accessible within experimental techniques. CFD can quantify and correlate the local haemodynamics structures which might lead to in-stent restenosis. The aim of this work is to study the fluid dynamics of realistic stented coronary artery models which replicate the complete clinical procedure of stent implantation. Two cases of pathologic left anterior descending coronary arteries with their bifurcations are reconstructed from computed tomography angiography and conventional coronary angiography images. Results of wall shear stress and relative residence time show that the wall regions more prone to the risk of restenosis are located next to stent struts, to the bifurcations and to the stent overlapping zone for both investigated cases. Considering a bulk flow analysis, helical flow structures are generated by the curvature of the zone upstream from the stent and by the bifurcation regions. Helical recirculating microstructures are also visible downstream from the stent struts. This study demonstrates the feasibility to virtually investigate the haemodynamics of patient-specific coronary bifurcation geometries.     

高压电气设备支架串联体系地震响应半解析法

通过论述高压电气设备支架串联体系地震响应半解析法的运算过程,说明地震响应半解析法对于电力系统防震工作的帮助。     

血浆内脂素与冠心病及其相关危险因素关系的研究

脂肪组织能够分泌多种脂肪细胞因子,它们在脂代谢、糖代谢及心血管疾病中都有着重要的作用。内脂素是一种新型脂肪细胞因子,它与心血管疾病特别是冠状动脉粥样硬化性心脏病的发生有着密切的关系,它对动脉粥样硬化起着重要的作用。研究内脂素与冠心病及其相关危险因素的关系,为冠心病的治疗和其危险因素的控制提供了新的治疗研究方向。     

Assessing Antioxidant Activities of Phenolic Compounds of Common Turkish Food and Drinks on In Vitro Low-Density Lipoprotein Oxidation

ABSTRACT: The total phenol concentrations of solid (9 types of vegetables and 6 types of fruits) and liquid (10 different types of drinks) foods were determined by the Folin-Ciocalteu colorimetric method. Oxidized low-density lipoprotein (LDL) was formed in in vitro conditions, and the effects of the phenolic compound extracts were measured on the inhibition of LDL oxidation. The phenol concentration for the 50% inhibition of LDL oxidation (IC₅₀) and the phenol antioxidant index (PAOXI) were calculated. Walnut (7052 mg/kg) and Turkish coffee (2389 mg/L) had the highest total phenol concentrations. Green pepper and orange nectar had the lowest IC₅₀ values, whereas walnut and red wine had the highest PAOXI values.     

Biodegradable metals for cardiovascular stent application: interests and new opportunities

During the last decade, biodegradable metallic stents have been developed and investigated as alternatives for the currently-used permanent cardiovascular stents. Degradable metallic materials could potentially replace corrosion-resistant metals currently used for stent application as it has been shown that the role of stenting is temporary and limited to a period of 6-12 months after implantation during which arterial remodeling and healing occur. Although corrosion is generally considered as a failure in metallurgy, the corrodibility of certain metals can be an advantage for their application as degradable implants. The candidate materials for such application should have mechanical properties ideally close to those of 316L stainless steel which is the gold standard material for stent application in order to provide mechanical support to diseased arteries. Non-toxicity of the metal itself and its degradation products is another requirement as the material is absorbed by blood and cells. Based on the mentioned requirements, iron-based and magnesium-based alloys have been the investigated candidates for biodegradable stents. This article reviews the recent developments in the design and evaluation of metallic materials for biodegradable stents. It also introduces the new metallurgical processes which could be applied for the production of metallic biodegradable stents and their effect on the properties of the produced metals.     

Statin Treatment Improves Plasma Lipid Levels but not HDL Subclass Distribution in Patients Undergoing Percutaneous Coronary Intervention

Despite the established efficacy of statin therapy, the risk of cardiovascular events remains high in many patients. We examined high-density lipoprotein (HDL) subclass distribution profiles among statin-treated coronary heart disease (CHD) patients undergoing percutaneous coronary intervention (PCI). Plasma HDL subclasses were measured in 85 patients with established CHD and quantified by two-dimensional gel electrophoresis and immunoblotting. In CHD patients with statin treatment, the mean value of total cholesterol (TC) reached the desirable level and the triacylglycerol level (TAG) was borderline high. Moreover, low density lipoprotein cholesterol (LDL-C), high density lipoprotein cholesterol (HDL-C), apolipoproteinA-I, and apolipoproteinB-100 levels in these patients resembled those in normolipidemic healthy subjects. The HDL subclass did not show a normal distribution and was characterized by the lower large-sized HDL_2b contents and higher contents of small-sized preβ₁-HDL in CHD patients, compared to those in normolipidemic control subjects. Multiple stepwise regression analysis revealed that the severity of coronary stenosis, determined by the Gensini Score, was significantly and independently predicted by HDL_2b and HDL_3b. Statin therapy was effective in modifying plasma lipids levels, but not adequate as a monotherapy to normalize the HDL subclass distribution phenotype of patients with CHD undergoing PCI. The HDL subclass distribution may aid in risk stratification, especially in patients with CHD and therapeutic LDL-C and HDL-C levels.     

Development of weft‐knitted and braided polypropylene stents for arterial implant

Textile biomedical materials have been used for various applications contributing considerably in improving quality of life. The current study aims at improving polypropylene fibre stents which may replace metallic ones. In order to produce the stents, weft‐knitting and braiding technologies were used. In the braiding technique, by varying the take‐up ratio (using gears with the appropriate number of teeth in the braiding machine), it was possible to manufacture regular braids with angles of 65°, 70° and 75° in order to obtain different covers. In the knitting technique, a circular machine was used and the tightness of the structure was adjusted by varying the loop length and thus the fabric loop density, resulting in variations of the sample diameter. The knitting machine had negative feed, and so loop length variations were achieved by varying the yarn input tension, the stitch cam settings and the fabric take‐down tension. The samples were heat set. Yarns were contracted by setting at 130°C and 140°C, and this led to increasing the loop density and the flexural rigidity of the samples. A high cover of the samples resulted in a greater stiffness of the structures. The stents were evaluated by undertaking the tests required for arterial support: rigidity to radial compression, resistance to tensile forces and bending rigidity. The best results were obtained with braided structures. Future work may concentrate in improving the stent design and using new biocompatible fibres.     

急性冠脉综合征患者PCI术后短程双联抗栓后单用替格瑞洛的疗效观察

目的：观察经皮冠状动脉介入治疗（percutaneous coronary intervention, PCI）的急性冠脉综合征（acute coronary syndrome, ACS）患者短程双联抗栓后单用替格瑞洛抗血小板治疗的临床疗效。方法：选取2018年10月至2021年12月我院及江苏省苏北人民医院接受过PCI术的ACS患者172例,根据患者服药情况分为3组：A组（单纯替格瑞洛组）50例;B组（阿司匹林肠溶片+替格瑞洛组）62例;C组（阿司匹林肠溶片+硫酸氢氯吡格雷组）60例。观察患者术后再发心绞痛、支架内再狭窄、再次血运重建、心衰、出血等情况。结果：3组之间术后再发心绞痛、支架内再狭窄、再次血运重建、心衰、出血无统计学差异。结论：PCI术后短程双抗后单用替格瑞洛抗血小板治疗患者缺血性事件、心衰无增加,而且可减少出血风险。     

冠心病药物治疗进展

冠心病治疗方法日新月异,不断有新型药物进入临床。抗血小板药物是冠心病治疗的基础,但目前尚无新型药物能撼动阿司匹林和P2Y12受体抑制剂的地位。炎症与冠心病的发生发展息息相关,抗炎治疗初露曙光,仍需进一步深入探索。本文拟就冠心病药物治疗的进展进行总结,为临床实践提供新的视野。     

NiTi合金表面微观形貌对血管内皮细胞及血小板黏附的影响

主要探讨血管支架材料--NiTi合金不同表面形貌对牛主动脉血管内皮细胞及血小板黏附的影响.采用机械抛光、机械刻蚀和化学浸蚀的方法制备微孔、微凹槽等微结构特征的NiTi合金表面.利用扫描电镜、粗糙度轮廓仪等对材料表面微观形貌和平均粗糙度进行表征,并测定微孔和微凹槽的材料表面对血小板及血管内皮细胞黏附的影响.结果表明:NiTi合金基体表面制备纳米级粗糙度的微孔和微凹槽等不同微观形貌对血小板黏附的影响不显著,但可明显促进内皮细胞的黏附;具有微孔结构的材料表面黏附的细胞数量最多,且细胞生长状态良好;材料表面微凹槽结构对细胞的早期黏附具有接触诱导效应.微粗糙化的各种不同材料表面形貌对血小板黏附的影响不显著.