冠状动脉内支架植入术治疗冠心病

目的：评价冠状动脉内支架植入术治疗冠心病的临床应用价值。方法：对86例102支冠状动脉病变内植入117只支架,其中植入左前降支51只,右冠状动脉46只,左回旋支20只。结果：支架植入后经冠状动脉造影证实狭窄消失,效果良好,其中26例急性心肌梗死患者由于急诊植入支架后,病情转危为安。86例全部植入成功,无一例发生严重的并发症。结论：冠状动脉内支架植入术是治疗冠心病的一种安全可靠、效果好的介入性治疗技术,有良好的应用价值。     

Suggestion of Potential Stent Design Parameters to Reduce Restenosis Risk driven by Foreshortening or Dogboning due to Non-uniform Balloon-Stent Expansion

The foreshortening or dogboning of a stent that occurs due to transient non-uniform balloon-stent expansion can induce a vascular injury, resulting in restenosis of the coronary artery. However, previous studies rarely considered the effects of transient non-uniform balloon expansion on analysis of the mechanical properties and behaviors of stents during stent deployment, nor did they determine design parameters to minimize the restenosis risk driven by foreshortening or dogboning. The aim of the current study was, therefore, to suggest potential design parameters capable of reducing the possibility of restenosis risk driven by foreshortening or dogboning through a comparative study of seven commercial stents using finite element (FE) analyses of a realistic transient non-uniform balloon-stent expansion process. The results indicate that using stents composed of opened unit cells connected by bend-shaped link structures, in particular the MAC Plus stent, and controlling the geometrical and morphological features of the unit cell strut or the link structure at the distal ends of stent may prevent restenosis risk caused by foreshortening or dogboning. This study provides a first look at the realistic transient non-uniform balloon-stent expansion by investigating the mechanical properties, behaviors, and design parameters capable of reducing the possibility of restenosis risk induced by the foreshortening or the dogboning.     

Delayed High Output Heart Failure due to Arteriovenous Fistula Complicated with Herniated Disc Surgery

A 36-year-old male presented with progressive exertional dyspnea over months. Physical examination showed jugular venous distension, lung crecipitations, femoral bruit and pitting pedal edema. Echocardiogram showed a dilated right ventricle with severe pulmonary hypertension and a non collapsing inferior vena cava (IVC). On right heart catheterization, IVC oxygen saturation was noted at 92% suggesting arterial mixing; a computed tomography of the abdomen showed a fistula between the right common iliac artery to the right common iliac vein at L4 level and a massive IVC; this was linked to trauma from a disectomy done 16 years ago at L4–L5 level. Endovascular sealing with a 16 × 60 mm bifurcated stent graft (S & G Biotech, Seoul, Korea) was performed which led to complete resolution of the patient’s dyspnea. Iatrogenic vascular injury during lumbar disc surgery, although rare, can lead to high output cardiac failure developing over months to years.     

支架参数对血管壁面剪切应力的影响

目的研究不同支架参数对血管壁面再狭窄的影响,为设计支架形式提供参考和依据。方法根据支柱的螺纹节距、支柱数目、支柱线径、支架突入流域深度、支柱截面形状对支架进行分组,利用三维计算流体动力学(computational fluid dynamics,CFD)模拟方法研究各个参数的不同设置对血管壁面剪切应力分布的影响。结果支架的支柱线径对壁面剪切应力影响最为显著,并且支架参数中节距变短、支柱数目增加、线径变宽、突入流域深度增加会导致壁面低剪切应力区域面积增加;相对于三角形与正方形截面形状,圆形截面支架导致的低剪切应力区域面积更少。结论支架在设计过程中应采用圆形截面,而且应尽可能缩小线径,增长节距,减少支柱数目,减小突入流域深度。     

支架介入治疗颈内动脉狭窄和动脉瘤对动脉瘤壁面压力的影响

目的研究当狭窄与动脉瘤毗邻时,使用支架介入治疗后对动脉瘤壁面压力产生的影响。方法使用计算流体动力学分析的方法对动脉瘤模型及狭窄和动脉瘤毗邻的模型进行对比研究。构建3个模型(M1、M2、M3)对压力变化进行分析比较。M1是颈内动脉瘤模型(无狭窄、无支架),在M1中的动脉瘤前构造一段狭窄动脉形成M2,在M2的动脉瘤部位植入支架后形成M3。结果 M2、M1两个模型相比较,轻度狭窄(50%)引起的动脉瘤部位的压力增加约为1.369 9 kPa(10.3 mmHg)(收缩期的峰值时刻),一个心动周期内动脉瘤部位的平均压力增加约为0.572 kPa(4.3 mmHg)。M3、M2两个模型相比较,动脉瘤部位的压力增加大约为1.037 kPa(7.8 mmHg)(收缩期的峰值时刻),一个心动周期内动脉瘤部位的平均压力增加大约为0.399 kPa(3 mmHg)。结论当使用支架治疗狭窄与弯曲颅内动脉瘤毗邻的患者时,轻度狭窄不会导致显著压力增加。载瘤动脉的形状、动脉瘤或动脉狭窄疾病确实对动脉瘤部位压力变化有影响。     

支架治疗主动脉弓内侧动脉瘤的仿真研究

血管内支架是治疗主动脉弓动脉瘤的一种新技术。目前还没有人对具有局部突起的动脉瘤支架治疗血流动力学进行过研究。基于这样的事实,本仿真研究对主动脉弓内侧动脉瘤的支架治疗进行血流动力学分析。为便于比较,分别建立了有支架和无支架的主动脉弓动脉瘤模型。利用计算流体力学的方法对两个模型中的生理性血液流动进行了仿真。对流动情形、压力和壁面切应力分布进行了比较和分析,以便评价血管内支架对主动脉弓动脉瘤治疗的效果。结果表明,有支架的模型和无支架的模型,在瘤腔内的流动情形具有显著的不同。有支架模型瘤腔内的流动受到明显的抑制,特别是局部突起处的压力和壁面切应力大大地减小了。这些现象使我们有理由推断,血管内支架可以促进瘤腔内血栓的形成,并能减小动脉瘤破裂的危险。     

Studying the non-uniform expansion of a stent influenced by the balloon

Non-uniform expansion of cardiovascular stents, which exists widely in experiments, has a large influence on stent safety, but has seldom been studied in depth until now. In this paper we use a folded balloon with friction to expand a stent through finite element method (FEM), and study how this influences non-uniform expansion of the stent. The simulations were carried out using ABAQUES software. The results show that the stent expands non-uniformly only when the fold and friction are considered together in the FEM model. The extent of non-uniformity during expansion increases with rising friction coefficient values; with the same friction coefficient but different stent locations on the balloon the extent of non-uniform deformation is different. On the other hand, compared to a tri-folded balloon, a six-folded balloon clearly decreases the expansive non-uniformity, which means that by increasing the number of the folded parts of balloon the stent expands more uniformly.     

Prospects for the research and application of biodegradable ureteral stents: from bench to bedside

Abstract

Ureteral stents are commonly used in urological practices but are frequently associated with patient discomfort, encrustation and stent-related infection. And a second procedure is needed to remove the stent. New biomaterials and designs have been attempted to solve these problems. The development of biodegradable ureteral stent shows promising prospects in future clinical applications. This article reviews the biomaterials and preparation methods commonly used in the present study of biodegradable ureteral stents. To date, none of the technological developments has lead to the ‘ideal’ biodegradable ureteral stent, but much progress has been made in the stent design by improving the physical characteristics and biocompatibility of the biomaterials. The controllability of degradation, the biggest problem faced currently, still needs to be further improved. In the future, the nanotechnology and chemical modification of biomaterials may be able to further optimize the properties of degradation.     

股动脉及桡动脉双入路再通锁骨下动脉闭塞的临床研究

目的探讨症状性锁骨下动脉闭塞的股动脉及桡动脉双入路介入再通的方法及疗效。方法分析首都医科大学附属北京天坛医院2012年10月至2013年5月症状性锁骨下动脉闭塞股动脉及桡动脉双入路进行血管腔内球囊扩张及支架植入术的临床资料。结果研究共入选10例患者,双入路介入再通均获得成功,未出现近期手术并发症,随访15 d至6个月,经血管彩超及颅外血管计算机断层扫描血管成像(computed tomography angiography,CTA)检查均显示血流通畅良好,未发现病变部位再狭窄。结论对于股动脉及桡动脉双入路再通锁骨下动脉闭塞,血管腔内球囊扩张支架植入术是一种微创、安全、有效的治疗方法,手术操作简单,患者症状改善快且明显,可成为主要的治疗手段。     

Revascularización carotídea con stent: implicaciones clínicas y para el procedimiento de la presencia de una lesión suboclusiva

Introduction and objectives

The advisability of implanting a stent in carotid near-occlusion stenosis is a controversial topic. We have assessed procedural and clinical implications of stent implantation for carotid artery disease with near occlusion.

Methods

We included 205 patients who underwent carotid artery revascularisation with a stent. The group of patients with near-occlusion stenosis (n=54)was compared to the rest of the population (n=151).

Results

No differences were found between groups for age, sex, and the percentage of symptomatic patients (three-quarters of the population). Carotid stent revascularisation for near-occlusion stenosis presented a high procedural success rate (96%) similar to that of revascularisation processes for other lesions (98%). Stenting in cases of near-occlusion stenosis required increased use of proximal protection (54% vs. 20.5%, P<.001) and predilation (33% vs. 17%, P=.01). The process to repair near-occlusion stenosis cause increased detachment of plaque, as shown by higher percentages of macroscopic plaque captured by protection devices (18.5% vs. 7%, P=.01) and of perioperative ischaemic brain lesions (47% vs 31%, P = .07). At 30 days of follow-up, the tendency toward adverse neurological events (death, major and minor stroke) was higher in the near-occlusion group (9.2% vs. 3.2%, P=.08).

Conclusions

Stent revascularisation for near-occlusion carotid stenosis has a high procedural success rate; however, its higher plaque load was responsible for the increased rate of ischaemic brain lesions and adverse neurovascular events at 30 days post-procedure.