Hyperthermia by a nitinol stent in an alternating magnetic field:Safety and feasibility in rabbit esophageal cancer

Hyperthermia by heating in-stent is a potentially new method to treat esophageal cancer.This study assessed the safety of heating the rabbit esophagus with a nitinol stent in an alternating magnetic field (AMF) and investigated whether this method offers a therapeutic option for esophageal cancer.Nitinol stents were placed in the cervical esophagi of healthy rabbits,which were heated in an AMF for different times at 43,46 and 50 ℃.The esophagi were histologically examined after a week to observe whether there was transmural necroses.Then esophageal cancer of rabbit placed nitinol stents were heated in an AMF at 46℃ for 10 min.Stents were heated to a target temperature within 5 min.The highest tolerated temperature and time for the healthy rabbit esophagus was at 46℃ for 10 min.Tumor growth was delayed by heating and it was statistically significant.Heating the rabbit esophageal wall at 46℃ for 10 min proves to be safe and effective in delaying tumor growth.     

针织结构复合材料人工气管(支架)的开发

介绍了人体内管道再生工程所用的一种新型的可降解针织医用内支架及其制作原料、编织方法、涂层步骤；并对其拉伸和压缩等机械性能进行了初步的研究，证实了其力学上的可行性。     

热处理对于TiNi(Ni原子分数为50.6%)合金性能的影响

介绍了固熔热处理工艺对用于制造医用支架直径为 0 .8mm的TiNi(Ni原子分数为 5 0 .6 % )合金的影响 .研究的目的在于找到适合自扩张支架的马氏体相变完成温度Af.采用低温下时效处理的办法 ,在高低温度下对样品进行连续弯曲训练 ,以此来获得双向形状记忆效应 .通过不同的固熔热处理温度 ,发现合金完成马氏体相变时存在约 2 0℃的温度变化范围 ,且具有较好的形状回复率 .     

Forming of magnesium alloy microtubes in the fabrication of biodegradable stents

Magnesium alloys have, in recent years, been recognized as highly promising biodegradable materials, especially for vascular stent applications. Forming of magnesium alloys into high-precision thin-wall tubes has however presented a technological barrier in the fabrication of vascular stents, because of the poor workability of magnesium at room temperature. In the present study, the forming processes, i.e., hot indirect extrusion and multi-pass cold drawing were used to fabricate seamless microtubes of a magnesium alloy. The magnesium alloy ZM21 was selected as a representative biomaterial for biodegradable stent applications. Microtubes with an outside diameter of 2.9 mm and a wall thickness of 0.2 mm were successfully produced at the fourth pass of cold drawing without inter-pass annealing. Dimensional evaluation showed that multipass cold drawing was effective in correcting dimensional non-uniformity arising from hot indirect extrusion. Examinations of the microstructures of microtubes revealed the generation of a large number of twins as a result of accumulated work hardening at the third and fourth passes of cold drawing, corresponding to the significantly raised forming forces. The work demonstrated the viability of the forming process route selected for the fabrication of biodegradable magnesium alloy microtubes.     

应用支架术成功开通1例左锁骨下动脉慢性完全性闭塞8a病变临床分析

目的探讨锁骨下动脉慢性完全性闭塞(CTO)病程8 a的病变经皮腔内血管成形术(PTA)开通和成功植入支架的方法及效果.方法对头晕、头痛、左上肢无脉伴左上肢冷感、麻木、酸痛和活动时加重持续8 a的患者经左锁骨下动脉造影证实为左锁骨下动脉CTO病变的病例行支架术治疗.经右股动脉入路,置入8F指引导管,应用冠状动脉介入导丝PROGRESS,在小球囊(1.5 mm×15 mm)的支撑下通过病变到达左锁骨下动脉远端.应用1.5 mm×20 mm、2.0 mm×20 mm和4.0 mm×1 5 mm Maverick冠脉球囊12~16 atm×30 s依次预扩张病变全程,植入6.0 mm×57 mm Express支架.结果支架植入后,病变血管恢复血流TIMIⅢ级,桡动脉波动有力,患肢血压恢复正常,患者症状消失.结论 PTA和支架术是持久开通锁骨下动脉闭塞的有效方法,且操作简便,安全,近期和远期效果好.     

LVIS支架治疗前交通动脉瘤的初步经验

目的 探讨LVIS支架治疗前交通动脉瘤的初步经验。方法 自2015年6月至 2020年6月应用LVIS支架治疗前交通宽颈动脉瘤15例,其中14例采用支架辅助弹簧圈栓塞,分析患者的临床资料和疗效。结果 采用支架辅助弹簧圈栓塞14 例,术后即刻血管造影显示3例瘤颈不完全栓塞,其中1例术后5 d再出血,停用双抗后1个月造影复查完全栓塞。单纯支架植入1例,术后即刻血管造影显示造影剂滞留,1个月造影复查完全栓塞。15例3个月造影随访动脉瘤完全栓塞,载瘤动脉通畅无狭窄,无远期手术相关并发症。结论 LVIS支架治疗前交通宽颈动脉瘤是一种安全、有效的治疗方式,疗效好,但其技术难度相对较大,需要仔细操作。     

316L不锈钢表面聚乙烯-乙烯醇药物涂层的制备及性能

以316L不锈钢冠脉支架为模型,在经过表面处理的316L不锈钢基体表面制备了乙烯-乙烯醇共聚物药物涂层,采用戊二醛为交联剂对涂层表面进行交联改性,并对交联前后涂层的性能进行了比较,同时以紫杉醇为模型药物,研究了交联前后涂层药物的释放速率。结果表明:真空条件下制备的涂层表面平滑致密,交联后涂层力学强度增加,溶胀度及药物的溶解度降低,药物释放时间延长。     

巴马和贵州小型猪在冠状动脉支架评价中的应用

目的通过比较成年巴马小型猪和贵州小型猪的冠状动脉分型、血管弯曲度、左、右冠状动脉直径和植入支架直径,长期饲养后动物体重变化,探讨两种品系小型猪在冠状动脉支架评价中的应用。方法巴马小型猪9只,贵州小型猪12只,雌雄兼用。常规麻醉动物后,称重,行冠状动脉造影,目测冠脉直径,以过膨胀方式植入支架,再次行冠脉造影观察支架贴壁情况。术后常规饲养动物,饲喂阿司匹林和氯吡格雷抗凝。于支架植入后26周,再次麻醉动物,称重,行安乐死。比较两次实验动物体质量变化,由介入医师根据冠状动脉造影图像分析冠脉分型、血管弯曲度,采用图像分析软件测量植入支架段冠状动脉的最小直径和参考直径。结果两组动物均完成支架植入实验并存活至实验终点,死亡率0%。经过26周饲养,巴马小型猪的体质量变化显著小于贵州小型猪（P〈0.001）。两种小型猪冠状动脉均为右优势型,血管弯曲度〈30°。巴马小型猪的左冠状动脉前降支的参考直径和最小直径以及植入支架型号与贵州小型猪无统计学差异（P〉0.05）。巴马小型猪的右冠状动脉的参考直径明显小于贵州小型猪（P〈0.05）,最小直径和植入支架型号无统计学差异（p〉0.05）。结论利用活体、动态的冠状动脉造影分析,发现巴马和贵州小型猪的成年动物冠状动脉分型均一且与人类一致;血管弯曲度小、易于进行介入导管操作;主要分支直径适合植入直径2.75 mm或3.0 mm规格的冠脉支架。在慢性实验饲养过程中,成年动物的体重变化不大。因此,两种品系小型猪均适合冠脉支架评价研究。     

基于有限元仿真的食管支架疲劳寿命计算

介绍了食管支架的应用背景及其研究现状,用有限元数值模拟方法计算了食管支架的疲劳寿命.根据实际情况,提出合理的假设与简化条件,完成了几何模型及有限元模型的创建、材料模型的选取及边界条件的正确设置.通过对不同头数、不同丝径的裸架和覆膜支架的疲劳寿命的计算,得出支架丝径越大、头数越多,支架径向刚度和强度就越大,疲劳寿命也越大的结论.建立了食管支架体外加速疲劳试验装置,对不同头数、相同丝径的覆膜支架进行疲劳寿命的试验.试验结果与数值模拟结果一致,证明了数值模拟方法的合理性及有效性.数值模拟与试验相结合能为食管支架的优化设计提供有价值的参考.     

激光切割血管支架筋宽变化模型构建

在血管支架激光切割加工中存在着筋宽变化,影响支架撑开性能.基于激光切割血管支架的筋宽形成机理,构建出表述切割过程中支架筋宽变化的数学模型.理论计算及支架加工试验表明:管材激光切割点回转偏心量的大小是造成支架筋宽变化的主要因素;用数学模型指导调整机床,可将激光切割支架的筋宽变化控制在0.01 mm以下.