Stent fracture after transjugular intrahepatic portosystemic shunt placement using the bare metal stent/stent-graft combination technique

BACKGROUND A transjugular intrahepatic portosystemic shunt(TIPS)is widely placed to treat portal hypertension.Because the Viatorr®stent(W.L.Gore and Associates,Flagstaff,AZ,United States)is not available in all hospitals in China,the bare metal stent(BMS)/stent-graft combination technique is still popular for TIPS construction.Stent fracture is a complication after TIPS placement using this technique,with limited available literature focusing on it.AIM To assess the incidence of stent fracture after TIPS placement using the BMS/stent-graft combination technique and to identify the risk factors for stent fracture.We proposed technique modifications to improve the clinical results of TIPS placement with the BMS/stent-graft combination technique.METHODS We retrospectively analyzed the computed tomography(CT)data of all patients with portal hypertension who underwent the TIPS procedure between June 2011 and December 2021 in a single center.Patients implanted with the BMS/stent graft and had follow-up imaging data available were included.We identified patients with stent fracture and analyzed their characteristics.Multivariable logistic regression was applied to identify the potential predictors of stent fracture.RESULTS Of the 68 included patients,stent fracture occurred in seven(10.3%)patients.Based on CT images,the stent fractures were categorized into three types.Our study consisted of four(57.1%)type I fractures,one(14.3%)type II fracture,one(14.3%)type IIIa fracture,and one(14.3%)type IIIb fracture.After adjusting for covariates,multivariable logistic regression revealed that the risk factors for stent fracture were the implantation of a greater number of stents[adjusted odds ratio(aOR)=22.2,95%confidence interval(CI):1.2-415.4,P=0.038]and a larger proximal sagittal stent bending angle(aOR=1.1,95%CI:1.0-1.3,P=0.020).CONCLUSION Stent fracture occurred in approximately 10%of patients with portal hypertension who underwent TIPS with the BMS/stent-graft combination technique.The number of implanted stents and stent bending angle at the inferior vena cava end were predictors of stent fracture,which suggests that the incidence of stent fracture could potentially be reduced by procedural modifications.

Stent-grafts for the treatment of TIPS dysfunction:Fluency stent vs Wallgraft stent

AIM:To evaluate the clinical efficacy of an expanded polytetrafluoro-ethylene-covered Fluency stent compared with that of a polyethylene terephthalate-covered Wallgraft stent for the management of transjugular intrahepatic portosystemic shunt(TIPS)dysfunction.METHODS:A retrospective review of patients who underwent TIPS revision with stent-grafts between May 2007 and June 2011 was conducted.The patients were divided into two groups according to the stentgrafts implanted:the Fluency stent(Bard Incorporated,Karlsruhe,Germany)and the Wallgraft stent(Boston Scientific,Galway,Ireland).The primary patency rates were calculated and compared using the Kaplan-Meier method.RESULTS:A total of 73 patients were evaluated in this study:33 with Fluency stents and 40 with Wallgraft stents.The primary patency rates at 12 and 24 mo were 91% and 85%,respectively,in the Fluency stent group and 78% and 63%,respectively,in the Wallgraft stent group.The primary shunt patency rates after TIPS revision were significantly better with the Fluency stent than with the Wallgraft stent(P = 0.033).CONCLUSION:TIPS revision with the Fluency stent has higher medium-term patency rates than that with the Wallgraft stent.

Experimental and computational studies on the flow fields in aortic aneurysms associated with deployment of AAA stent-grafts

Pulsatile flow fields in rigid abdominal aortic aneurysm （AAA） models were investigated numerically, and the simulation results are found in good agreement with particle image velocimetry （PIV） measurements. There are one or more vortexes in the AAA bulge, and a fairly high wall shear stress exists at the distal end, and thus the AAA is in danger of rupture. Medical treatment consists of inserting a vascular stent-graft in the AAA, which would decrease the blood impact to the inner walls and reduce wall shear stress so that the rupture could be prevented. A new computational model, based on porous medium model, was developed and results are documented. Therapeutic effect of the stent-graft was verified numerically with the new model.

Short-term results in canines of novel stent-graft design for chimney technique in TEVAR

Introduction:Parallel stent-stent grafting is a major endovascular technique used to preserve the supra-aortic branches during thoracic endovascular aortic repair(TEVAR)of aortic pathologies involving the aortic arch.The short-and mid-term results of this technique are satisfactory;however,endoleak remains a major concern.Thus,here we designed a new chimney stent-graft to decrease the endoleak rate.Aim:To testify the feasibility and safety of the new chimney stent-graft system in a canine model.Material and methods:Six Labrador retrievers were used.Pre-operative data were collected and all operations were performed under general anesthesia.The main and chimney stent-grafts were implanted through the abdominal aorta and left subclavian artery approaches,respectively.Completion digital subtraction angiography(DSA)was performed to confirm the immediate outcomes.All dogs were fed separately for 6 months and sacrificed after aortic angiography.The thoracic aorta and the main and chimney stent-grafts were harvested for histopathologic examination.Results:No complications were found in follow-up DSA.All branch arteries were patent.In?ammatory responses were observed around the stent-grafts in 3 experimental animals,and slight hyperplasia was observed in the surrounding tissues compared with the normal vessels.There was no mural thrombus in the stent,endothelial cells were noted on the inner surface of the stent,and thrombus was formed in the outer skirt and gutter area.The histopathologic examinations revealed similar results to those of gross necropsy observations.Conclusions:This study demonstrated the feasibility and safety of the Longuette stent-graft and the first to report a revised stent-graft specific for chimney technique.

Stent-grafts placement for treatment of massive hemorrhage from ruptured hepatic artery after pancreaticoduodenectomy

AIM:To present a series of cases with life-threatening hemorrhage from ruptured hepatic artery pseudoaneurysm after pancreaticoduodenectomy(PD) treated with placement of stent-grafts.METHODS:Massive hemorrhage from ruptured hepatic artery pseudoaneurysm after PD in 9 patients(6 men,3 women) at the age of 23-75 years(mean 48 years),were treated with placement of percutaneous endovascular balloon-expandable coronary stent-grafts.All patients were not suitable for embolization because of a non-patent portal vein.One or more stent-grafts,ranging 3-6 mm in diameter and 16-55 mm in length,were placed to exclude ruptured pseudoaneurysm.Followup data,including clinical condition,liver function tests,and Doppler ultrasound examination,were recorded at the outpatient clinic.RESULTS:Immediate technical success was achieved in all the 9 patients.All stent-grafts were deployed in the intended position for immediate cessation of bleeding and preservation of satisfactory hepatic arterial blood flow.No significant procedure-related complications occurred.Recurrent bleeding occurred in 2 patients at 16 and 24 h,respectively,after placement of stent-grafts and treated with surgical revision.One patient died of sepsis 12 d after the interventional procedure.The remaining 6 patients were survived when they were discharged.The mean follow-up time was 10.5 mo(range 4-16 mo).No patient had recurrent bleeding after discharge.Doppler ultrasound examination verified the patency of hepatic artery and stent-grafts during the follow-up.CONCLUSION:Placement of stent-grafts is an effective and safe procedure for acute life-threatening hemorrhage from ruptured hepatic artery pseudoaneurysm.

Endovascular stent-grafts for acute and chronic type B aortic dissection: comparison of clinical outcomes

Objective To evaluate the early and mid-term results of endovascular repair for acute and chronic type B aortic dissection, and to compare the clinical outcomes between the 2 groups. Methods From May 2002 to December 2006, 50 patients with type B aortic dissection were treated by endovascular stent-graft. There were 23 patients in the acute aortic dissection (AAD) group and 27 patients in the chronic aortic dissection (CAD) group. All patients were followed up from 1 to 54 months (average, 17±16 months).The immediate and follow-up clinical outcomes were documented and compared between the 2 groups. Results Placement of endovascular stent-grafts across the primary entry tears was technically successful in all 50 patients. Compared to the CAD group, the AAD group had a higher percentage of pleural effusion (17.4% vs. 0%, P=0.04) and visceral /leg ischemia (26.1% vs 3.7%, P=0.04). Procedure related complications, including endoleak and post-implantation syndrome, occurred more frequently in the AAD group than in the CAD group (21.7% vs 3.7% and 30.4% vs 11.1%, respectively; P=0.08 and P=0.04). Kaplan–Meier analysis showed no difference in the survival rate at 4 years between the 2 groups (86.4% vs 92.3%, P=0.42 by log-rank test). However, the event-free survival rate was higher in patients with chronic dissection than in patients with acute aortic dissection(96.2% vs 73.9%; P=0.02 by log-rank test). Conclu- sions Endovascular repair with stent-graft was safe and effective for the treatment of both acute and chronic type B aortic dissection. However, both immediate and long term major complications occurred more frequently in patients with acute dissection than in those with chronic dissection.

New nitinol endovascular stent-graft system for abdominal aortic aneurysm with finite element analysis and experimental verification

Abdominal aortic aneurysm(AAA) is one of the most common and catastrophic manifestations of the acute aortic syndrome that can be treated with endovascular aneurysm repair(EVAR) which requires a specially designed stent-graft system.In this work, a self-expanding nickel–titanium(nitinol) stent-graft system is aiming at AAA using finite element analysis(FEA) methods to analyze both fatigue behaviors and radial forces.Based on the systematic analysis of the parametric variations, a final stent-graft system was developed by the selection and arrangement of the individual stent components, targeting an optimal performance for the treatment of AAA.Experimental tests, animal tests and clinical trials were carried out to confirm the results.Both animal trials and clinical trials showed comparable curative effects with Medtronic Endurant stent-graft(SG) systems.

Total endovascular repair of aberrant right subclavian artery using caster branched stent-graft

A 57-year-old man has 20-year history of hypertension presented with intermittent chronic pain in the chest area and shoulder blades over the last three months.Computed tomographic angiography(CTA)on admission revealed a chronic type B aortic dissection(TBAD)with an aberrant right subclavian artery(ARSA)crossed behind the trachea and bovine aortic arch(Figure IB).

Development of new endovascular stent-graft system for type B thoracic aortic dissection with finite element analysis and experimental verification

Endovascular repair of the thoracic aorta with self-expanding stent-grafts has been emerging as a less invasive alternative treatment compared with conventional open surgeries.Despite the promising efficacy and safety of endovascular stent grafting,the stent-graft failure remains a major concern in terms of stent migration,device fatigue,and the risk of endoleaks.Challenges associated with the stent-grafts involve optimized geometrical structure,lifetime fatigue resistance,and adequate radial support.In this work,a novel endovascular stent-graft system is developed specially for the treatment of Stanford type B thoracic aortic dissections(TAD).Numerical study with finite element analysis(FEA)was utilized to evaluate the mechanical behaviors of the individual stent component.Results of the simulation were validated by experimental tests.Based on the systematic analysis of the parametric variations,a final stent-graft system was developed by the selection and arrangement of the individual stent components,targeting an optimal performance for treatment of TAD.The optimized solution of the stent-graft system was tested in clinical trials,showing advantageous therapeutic efficacy.

Fatigue Performance of Fabrics of Stent-Grafts Supported with Z-Stents vs. Ringed Stents

Stent-grafts were commercialized rapidly and gained a broad clinical acceptance over the past two decades. However,relatively more recent recognition of particular stent-graft design shortcomings have been identified which need to be addressed. It appears that various stent-graft designs may be more or less resistant to metal fatigue and /or fabric abrasions which can lead to type III and type IV endoleaks over the long term. Therefore,it is necessary to investigate the fatigue performance of the most common stentgraft designs: Z-stents and ringed stents,in a long-term in vitro fatigue simulation environment. This paper aimed to analyze nondestructively( gross observations) and destructively( fabric characteristics,mechanical and chemical properties) in order to put forward suggestions to improve the fabric and stent characteristics that may prevent type III and IV endoleaks. The fabric supported with ringed stent-grafts remained nearly completely intact after 168h. However, the fabric supported with Z-stents demonstrated significant damage. Fabric characteristics and tensile strength of the fibers did not present a significant difference between the control and fatigue simulated specimens. The crystallinity declined for both specimens. The fatigue performance of fabrics supported with ringed stents appears to be superior to that supported with Z-stents. The potential for a dynamic and destructive interaction between the apices of Z-stents which can lead to fraying and /or tearing of the graft fabric must be addressed in future designs.

Endovascular stent-grafts for acute and chronic type B aortic dissection: comparison of clinical outcomes

Within the recent months, endovascular repair of aortic aneurysms has become a rather interesting alternative to patients considering open surgery. In the past, the procedure was typically and more solely reserved to a selected group of elderly patients with several co-morbidities.……

Mid-term outcomes of left subclavian artery revascularization with Castor stent graft in treatment of type B aortic dissection in left subclavian artery

Background:Here we analyzed mid-term data of thoracic endovascular aneurysm repair(TEVAR)surgery with Castor single-branched stent graft placement for the management of Stanford type B aortic dissection(STBAD)involving the left subclavian artery(LSA).Methods:Between April 2014 and February 2019,32 patients with STBAD involving a Castor single-branched stent graft were included.We analyzed their outcomes,including technical success rate(TSR),surgical duration(SD),presence of ischemia,perioperative complications,LSA patency,and survival rate(SR),using computed tomography angiography and clinical evaluation during mid-term follow-up.Results:The mean patient age was 54.63±12.37 years(range,36–83 years).The TSR was 96.88%(n=31/32).The mean SD was 87.44±10.89 with a mean contrast volume of 125.31±19.30 mL.No neurological complications or deaths occurred during the study period.The patients had a mean hospital stay of 7.84±3.20 days.At a mean follow-up of 68.78±11.26 months,four non-aortic deaths(12.5%)were observed.The LSA patency rate was 100%(n=28/28).There was only one case of type I endoleak immediately after surgery(3.12%)(type I from LSA).However,none of the patients experienced type II endoleaks,and there were no cases of retrograde type A aortic dissection or stent graft-driven new distal entry.Finally,all patients exhibited good LSA patency.Conclusion:TEVAR using a Castor single-branched stent graft may be a highly feasible and efficient procedure for the management of STBAD involving the LSA.

Case Report of a Pseudoaneurysm of Ascending Aorta Treated by Stent

Pseudoaneurysms of the ascending aorta are a rare complication of aortic and cardiac surgery. In this article, we present a clinical case of a 56-year-old patient with a fortuitous diagnosis of a pseudoaneurysm of ascending aorta that was treated by an endovascular stent-graft. We discuss in this article the diagnostic and therapeutic aspect of the case and the place of endovascular treatment for the ascending aorta.

Willis覆膜支架系统治疗血泡样动脉瘤的效果

目的探讨Willis覆膜支架系统治疗血泡样动脉瘤的安全性及远期效果。方法选取我院2015年6月～2017年6月收治的9例血泡样动脉瘤患者作为研究观察对象,共9枚动脉瘤。患者均行Willis覆膜支架系统治疗,统计患者的手术结果 ,采用美国国立卫生院神经功能缺损量表(NIHSS)评价患者手术前后及术后1年的神经功能缺损情况;评估手术安全性,随访1年,统计患者的复发率。结果 9例患者中有7例患者均一次成功置入支架,一次成功率为77.78%,1例患者置入支架后出现内漏现象,再置入1枚支架后,DSA造影显示动脉瘤消失;还有1例患者由于动脉血管比较迂曲,置入过程中支架脱落,利用微导丝把支架取出后换用较短的覆膜支架,成功置入。患者术后的NIHSS评分为(5.04±2.53)分,低于术前的(7.49±2.49)分,差异有统计学意义(P<0.05)。9例患者中有1例患者由于微导丝刺破血管出现出血,行相应治疗后顺利恢复。术后随访1年,患者均无复发,有1例患者经DSA复查发现载瘤动脉出现轻度狭窄,但不影响神经功能。术后1年,患者的NIHSS评分为(4.72±2.32)分,与术后比较,差异无统计学意义(P>0.05)。结论采用Willis覆膜支架系统治疗血泡样动脉瘤的安全性高,远期效果好,值得推广。

大动脉覆膜支架系统生物学安全性评价研究

对大动脉覆膜支架系统进行生物学安全性评价。按照国家标准GB/T16175-1996、GB/T16886-1997的有关规定,对大动脉覆膜支架系统进行生物学安全性评价研究。结果表明:大动脉覆膜支架系统各项生物学指标均合格。大动脉覆膜支架系统各项生物学指标均符合国家标准GB/T14233.2-1993、GB/T16175-1996、GB/T16886-1997的要求,具有良好的生物相容性。

外科与介入手术治疗冠状动脉心肌桥临床疗效和预后的系统评价

目的通过系统评价的方法对比外科手术与介入手术治疗冠状动脉心肌桥的疗效及预后。方法通过关键词搜索在PubMed、EMbase、Cochrane Library、知网和万方数据库进行系统性检索,获取关于手术治疗冠状动脉心肌桥的研究文献。经研究者筛选文献、提取资料后,对纳入的研究进行系统评价与分析,并对样本量、手术方式、国家(亚洲和其他)、发表年份进行回归分析探索异质性来源。结果共获取3 584篇英文文献,1 678篇中文文献,去除重复后共计4 019篇文献。最终纳入33项研究,共计1 286例患者进行定性分析。其中26项研究共计572例患者纳入定量分析。单个率的合成分析显示:手术治疗冠状动脉心肌桥的总体症状缓解率为88.00%(95%CI:81.31%~93.56%),总体术后血管再狭窄率为9.09%(95%CI:4.30%~15.05%),术中并发症及术后心血管事件率分别为0.59%(95%CI:0.00%~1.83%)、0.46%(95%CI:0.00%~1.63%)。回归分析显示术后症状缓解率、血管再狭窄率与不同手术方式具有相关性(P<0.001),而与样本量、发表年份、国家无关(P>0.1)。亚组分析显示外科手术术后症状缓解率(95.45%vs 67.21%,P<0.001)、血管再狭窄(3.89%vs 24.33%,P<0.001)与术后心血管事件(0.01%vs 2.91%,P<0.001)均优于介入手术,外科手术和介入手术在术中并发症发生率(1.65%vs 0.00%,P=0.1 405)无明显差异。结论当前证据表明外科手术相对于介入手术在治疗冠状动脉心肌桥具有较高的术后症状缓解率和较低的血管再狭窄率,不过仍需开展更高质量的大样本随机对照试验加以验证。

Endovascular management of visceral artery aneurysms: When to watch, when to intervene?

Visceral artery aneurysms(VAA) include splanchnic and renal artery aneurysms. They represent a rare clinical entity, although their detection is rising due to an increased use of cross-sectional imaging. Rupture is the most devastating complication, and is associated with a high morbidity and mortality. In addition, increased percutaneous endovascular interventions have raised the incidence of iatrogenic visceral artery pseudoaneurysms(VAPAs). For this reason, elective repair is preferable in the appropriately chosen patient. Controversy still exists regarding their treatment. Over the past decade, there has been steady increase in the utilization of minimally invasive, non-operative interventions, for vascular aneurysmal disease. All VAAs and VAPAs can technically be fixed by endovascular techniques but that does not mean they should. These catheter-based techniques constitute an excellent approach in the elective setting. However, in the emergent setting it may carry a higher morbidity and mortality. The decision for intervention has to take into account the size and the natural history of the lesion, the risk of rupture, which is high during pregnancy, and the relative risk of surgical or radiological intervention. For splanchnic artery aneurysms, we should recognize that we are not, in reality, well informed about their natural history. For most asymptomatic aneurysms, expectant treatment is acceptable. For large, symptomatic or aneurysms with a high risk of rupture, endovascular treatment has become the firstline therapy. Treatment of VAPAs is always mandatory because of the high risk of rupture. We present our point of view on interventional radiology in the splanchnic arteries, focusing on what has been achieved and the remaining challenges.

Stent placement is effective on both postoperative hepatic arterial pseudoaneurysm and subsequent portal vein stricture:A case report

To treat postoperative bleeding after hepato-pancreato-biliary surgery, interventional radiology has become essential. We report a case of coincidental pseudoan-eurysm and jejunal varices that were both successfully treated by stent-grafts. After a pancreaticoduodenec-tomy, the patient developed a pseudoaneurysm in the hepatic artery and a stenosis in its periphery. After establishing hepatic arterial flow by placing stent-grafts over both the pseudoaneurysm and the stenosis, the pseudoaneurysm was embolized with microcoils. Nine months later, the patient developed jejunal varices caused by a severe stricture in the main trunk of the portal vein. Percutaneous transhepatic portography was performed and stent-grafts were placed over the stenotic segment. A venoplasty using stent-grafts nor-malized the portal blood flow and the jejunal varices vanished. Although stenosis occurred due to scarred tissues from leakage after pancreaticoduodenectomy, stent-grafts were useful for managing jejunal bleeding post-operatively.

胸主动脉共用覆膜和裸支架系统体内血栓形成的评价

背景:胸主动脉支架系统类器械一般由覆膜支架和金属裸支架及相应的输送系统构成,由于此类器械结构的复杂性,导致临床上可能带来更多关于血栓安全性的担忧。目的:为覆膜支架和裸支架联合使用的植入血管类器械上市前安全性评价的设计和结果分析提供更完整的思路。方法:选取3只实验猪,均植入胸主动脉支架系统,该系统包括胸主动脉支架系统输送器、胸主动脉支架系统覆膜支架、胸主动脉支架系统裸支架三部分,将覆膜支架植入实验动物的降主动脉段,并导入胸主动脉裸支架衔接于胸主动脉覆膜支架的远端,术中,对回撤至体外的输送器部分观察其表面血栓形成情况。术后7 d,取胸主动脉支架系统覆膜支架、裸支架与输送器部分,进行扫描电镜观察;取胸主动脉支架系统裸支架和覆膜支架接触部位血管,进行组织学观察。结果与结论:(1)大体观察显示,实验动物重要脏器未见血栓形成和血栓相关病变,植入部位血管的管腔中未见血栓性闭塞。(2)扫描电镜显示,覆膜支架系统输送器与裸支架系统输送器表面均可见几微米至上百微米大小的血栓分布,覆膜支架、裸支架表面及与支架接触的血管表面均可见几微米至几百微米大小的血栓分布。(3)组织学观察显示,覆膜支架接触部位血管内膜增生,新生组织大多由纤维蛋白网络大量红细胞构成,组织内部有炎性细胞浸润,少量新生组织边缘可见炎性细胞聚集,新生组织中局部有新生小血管形成;裸支架接触部位血管内膜增生,新生组织多由坏死的细胞构成,局部有聚集的炎性细胞。(4)结果表明,覆膜支架和裸支架联合使用的植入类器械植入后对血管产生的影响因组成不同而不同,需要考虑支架本身组成的特殊性,结合其临床使用方式,针对各组成部分进行分别评价分析。

The interactions between bloodstream and vascular structure on aortic dissecting aneurysmal model: A numerical study

Stent-graft implantation is an important means of clinical treatment for aortic dissecting aneurysm （ADA）. However, researches on fluid dynamics effects of stent were rare. Computer simulation was used to investigate the interactions between bloodstream and vascular structure in a stented ADA, which endures the periodic pulse velocity and pressure. We obtained and analyzed the flow velocity distribution, the wall displacement and wall stress in the ADA. By comparing the different results between a non-stented and a stented ADA, we found that the insertion of a vascular graft can make the location of maximum stress and displacement move from the aneurysm lumen wall to the artery wall, accompanied with a greatly decrease in value. These results imply that the placement of a stent-graft of any kind to oc-clude ADA will result in a decreased chance of rupture.