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.

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.

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.

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.

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).

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.……

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.

Total endovascular repair of an intraoperative stent-graft deployed in the false lumen of Stanford type A aortic dissection: A case report

BACKGROUND A 46-year-old male underwent ascending aortic replacement,total arch replacement,and descending aortic stent implantation for Stanford type A aortic dissection in 2016.However,an intraoperative stent-graft was deployed in the false lumen inadvertently.This caused severe iatrogenic thoracic and abdominal aortic dissection,and the dissection involved many visceral arteries.CASE SUMMARY The patient had pain in the chest and back for 1 mo.A computed tomography scan showed that the patient had secondary thoracic and abdominal aortic dissection.The ascending aortic replacement,total arch replacement,and descending aortic stent implantation for Stanford type A aortic dissection were performed 2 years prior.An intraoperative stent-graft was deployed in the false lumen.Endovascular aneurysm repair was performed to address this intractable situation.An occluder was used to occlude the proximal end of the true lumen,and a covered stent was used to direct blood flow back to the true lumen.A three-dimensional printing technique was used in this operation to guide prefenestration.The computed tomography scan at the 1stmo after surgery showed that the thoracic and abdominal aortic dissection was repaired,with all visceral arteries remaining patent.The patient did not develop renal failure or neurological complications after surgery.CONCLUSION The total endovascular repair for false lumen stent-graft implantation was feasible and minimally invasive.Our procedures provided a new solution for stent-graft deployed in the false lumen,and other departments may be inspired by this case when they need to rescue a disastrous stent implantation.

Research and clinical translation of trilayer stent-graft of expanded polytetrafluoroethylene for interventional treatment of aortic dissection

The aortic dissection(AD)is a life-threatening disease.The transcatheter endovascular aortic repair(EVAR)affords a minimally invasive technique to save the lives of these critical patients,and an appropriate stent-graft gets to be the key medical device during an EVAR procedure.Herein,we report a trilayer stent-graft and corresponding delivery system used for the treatment of the AD disease.The stent-graft is made of nitinol stents with an asymmetric Z-wave design and two expanded polytetrafluoroethylene(ePTFE)membranes.Each of the inner and outer surfaces of the stent-graft was covered by an ePTFE membrane,and the two membranes were then sintered together.The biological studies of the sintered ePTFE membranes indicated that the stent-graft had excellent cytocompatibility and hemocompatibility in vitro.Both the stent-graft and the delivery system exhibited satisfactory mechanical properties and operability.The safety and efficacy of this stent-graft and the corresponding delivery system were demonstrated in vivo.In nine canine experiments,the blood vessels of the animals implanted with the stent-grafts were of good patency,and there were no thrombus and obvious stenosis by angiography after implantation for 6months.Furthermore,all of the nine clinical cases experienced successful implantation using the stent-graft and its postrelease delivery system,and the 1-year follow-ups indicated the preliminary safety and efficacy of the trilayer stent-graft with an asymmetric Z-wave design for interventional treatment.

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.

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.

Stent-grafting combined with transcatheter embolization for a ruptured isolated hypogastric artery aneurysm

Rupture of isolated hypogastric artery aneurysm （HAA） is rarely encountered and is associated with a high mortality rate. Conventional surgery can not achieve distal control easily and may cause substantial blood loss, yielding high operative morbidity and mortality. On March 17, 2005, we treated a patient with such a disease successfully by using endovascular stent-grafting combined with transcatheter embolization.

Customized and in situ fenestrated stent-grafts:A reinforced poly-ε-caprolactone branch cuff designed to prevent type III endoleaks and enhance hemodynamics

Superior long-term anchorage of the bridging stent-grafts from the fenestrated main body endograft could be achieved with the addition of a flared cuff,capable of preventing the previously observed fabric fraying around the fenestration as a result of the balloon angioplasty of the seal zone.This novel stent cuff design will also facilitate more complete biointegration of the devices,eliminate the hemodynamic variation as well as significantly reduce the possibility of a Type III endoleak.The feasibility of this concept is demonstrated by observations made from in-situ tests performed in a Beta endograft design.Flared cuffs made of poly(ε-caprolactone)supported with a weft-knitted polyester structure can be manufactured with various configurations to optimize the transition from the main body of the endograft,thus preventing the currently marketed designs’hemodynamic perturbation while also promoting endograft biointegration.This concept represents an evolution in branch graft design,which may enhance the long-term durability of customized fenestrations and open new applications for in-vivo graft fenestration in the near future.Further ongoing investigation to optimize its structure,X-ray opacity,fixation to the flared stent,and material biocompatibility are still required to build upon this concept’s proof.

A novel pressure difference-induced perforation aortic stent-grafts system： an experimental study

Background Most of endovascular stent-graft modifications to preserve side branch must be customized according to extensive pre-operative assessment, which may not be possible in many hospitals and emergency settings. The study was to develop a novel stent-grafts system that would allow in situ ＂fenestration＂, with less reliance on preoperative imaging. Methods The magnitude of pressure difference （PD） between left subclavian artery （LSA） and aortic arch were measured in 12 experimental pigs. Changes of PD before and after LSA was covered were analyzed respectively. The novel stent graft was made by multi-dimensional and multiple textiles forming technology. According to the PD measurement in pigs, we evaluated the feasibility of the stent-graft in a mock circulation system. Results In pigs, the blood pressure of aortic arch was significantly higher than that of LSA after it was covered （P 〈0.001） and PD was （42.78±5.17） mmHg. After target vessel was covered and when PD between the LSA and aorta reached the magnitude measured in pigs, contrast media oozed from the cranny of graft to the LSA, which was generated by sliding and deformation of yarns of novel stent-graft. Conclusions The study proposes the design of pressure difference-induced perforation aortic stent-grafts system and verifies that the PD between LSA and aortic arch is high enough to allow in situ ＂fenestration＂ by stent graft made by multi-dimensional and multiple textiles forming technoloav.

体外预开窗联合束径技术在复杂主动脉病变中的应用

目的评价体外预开窗联合束径技术在复杂主动脉病变中的应用价值。方法回顾性收集2019年12月至2022年5月郑州大学第一附属医院血管外科收治的接受体外预开窗联合束径技术腔内修复治疗的9例复杂主动脉病变患者的临床资料,其中Stanford B型主动脉夹层4例,复杂腹主动脉瘤5例。分析手术成功率、手术时间、住院时间、围手术期死亡率、随访情况。结果9例复杂主动脉病变患者中6例接受三开窗,3例接受四开窗,共重建分支动脉血管30条,植入分支支架(BSG)26条。手术成功率为100.0%(9/9),无术中死亡病例。手术时间211~440 min,平均(333.0±70.8)min。住院时间10~33 d,平均(21.8±7.6)d。1例患者在围手术期死亡,围手术期死亡率为11.11%(1/9),死因为呼吸循环衰竭。术后随访时间0.2~14.6个月,平均随访时间(6.6±5.2)个月;随访过程无患者死亡,再处理2例(25.00%),1例患者出现左肾动脉分支支架内血栓形成,予以机械抽栓并球囊扩张,1例患者右肾动脉分支支架脱入主体支架内,予以腔内技术取出并补装BSG,其余患者主动脉病变重塑良好,无不良并发症。结论体外预开窗联合束径技术腔内修复治疗复杂主动脉疾病的短中期效果满意,具有较好的安全性、可行性。

颈动脉狭窄合并冠心病同期外科治疗的疗效分析:单中心经验

目的总结同期颈动脉血运重建手术及冠状动脉血运重建手术治疗颈动脉狭窄合并冠心病患者的单中心临床经验。方法回顾性分析2008年1月至2020年1月中日友好医院心脏血管外科收治的54例颈动脉狭窄合并冠心病患者资料,其中同期行颈动脉内膜剥脱术(carotid endarterectomy,CEA)+冠状动脉搭桥术(coronary artery bypass grafting,CABG)38例,同期行颈动脉支架植入术(carotid artery stenting,CAS)+CABG 16例。结果手术成功率100%。围手术期内出现小卒中3例,短暂性脑缺血发作4例,术后短暂低血压8例,术后高灌注综合征3例,二次开胸3例,心肌梗死4例;无围手术期死亡病例。同期CEA+CABG组与同期CAS+CABG组的手术时间、术中出血量、围手术期输血量、神经系统并发症和循环系统并发症发生率差异均无统计学意义(P>0.05)。48例患者获得随访,随访时间29~140个月,平均(89.8±35.6)个月,因心肌梗死和心功能不全死亡患者各1例。结论同期CEA+CABG与同期CAS+CABG治疗颈动脉狭窄合并冠心病患者均安全有效。

急性A型主动脉夹层患者全弓替换加支架象鼻手术中远端主动脉弓部阻断的效果观察

目的观察急性A型主动脉夹层患者全弓替换加支架象鼻手术中实施远端主动脉弓部阻断的治疗效果。方法急性A型主动脉夹层患者21例,均接受全弓替换加支架象鼻手术治疗,术中均采用远端主动脉弓部阻断技术阻断主动脉弓部,停循环温度为28℃中度低温。结果21例患者均顺利完成手术治疗,手术时间(8.2±1.8)h,其中术中停循环时间(4.5±0.8)min、选择性脑灌注时间(42.5±9.6)min、术中体外循环时间(206.8±16.6)min、升主动脉阻断时间(135.7±22.0)min。21例患者中,19例患者治愈出院,2例患者术后死亡。治愈出院的19例患者中,2例患者出现术后并发症,1例因急性肾功能衰竭行床旁血滤治疗,1例因术后出血进行二次开胸止血。术后死亡的2例患者中,1例因冠脉事件死亡、1例因感染中毒性休克死亡。19例患者出院后复查主动脉CTA结果显示,支架人工血管通畅,未见钳夹损伤、变形或扭曲,远端吻合口附近无内漏形成,7例支架血管置入部位夹层假腔完全血栓化、11例部分血栓化、1例全程胸降主动脉和腹主动脉假腔完全血栓化。结论在全弓替换加支架象鼻手术治疗急性A型主动脉夹层过程中,采用远端主动脉弓部阻断技术阻断主动脉弓部,可以避免深低温停循环,有效缩短了术中停循环时间,有助于减少术后并发症。

覆膜支架腔内修复术对StanfordB型主动脉夹层治疗效果与安全性的Meta分析

目的使用Meta分析的方法系统评价覆膜支架腔内修复术对Stanford B型主动脉夹层(TBAD)的治疗效果与安全性。方法系统检索中国知网、万方数据库、维普、中国生物医学文献数据库、PubMed、Embase、the Cochrane Library和Web of Science等中英文数据库,收集覆膜支架腔内修复术治疗TBAD的随机对照试验(RCTs),检索时间为建库至2023年10月31日。对纳入文献进行质量评价并提取数据,应用Stata 16.0和RevMan 5.4软件对各项结局指标进行Meta分析。结果共纳入13篇RCTs进行Meta分析,包括1114例TBAD患者,其中575例接受覆膜支架腔内修复术。Meta分析结果显示,接受覆膜支架腔内修复术的试验组在生存率(OR=6.51,95%CI:3.50~12.11,P<0.01),再次手术或介入率(OR=0.33,95%CI:0.21~0.52,P<0.01),天门冬氨酸氨基转移酶(MD=-23.02 U/L,95%CI:-25.01~-21.03,P<0.01)、丙氨酸氨基转氨酶(MD=-14.28 U/L,95%CI:-15.58~-12.99,P<0.01)、血尿素氮(MD=-1.35 mmol/L,95%CI:-1.63~-1.06,P<0.01)和肌酐(MD=-23.43 mmol/L,95%CI:-26.30~-20.57,P<0.01)等肝肾功能指标上较对照组均显著改善。试验组TBAD患者内漏(OR=6.11,95%CI:0.73~51.34,P=0.10)和血管梗塞(OR=3.00,95%CI:0.31~29.16,P=0.34)的发生率与对照组差异无统计学意义;试验组脑梗塞(OR=0.14,95%CI:0.03~0.65,P=0.01)、肝肾功能障碍(OR=0.22,95%CI:0.07~0.74,P=0.01)和总并发症发生率(OR=0.30,95%CI:0.17~0.54,P<0.01)低于对照组,组间差异具有统计学意义。结论覆膜支架腔内修复术可有效改善TBAD患者的生存率,降低再次手术或介入率,在整体并发症上具有较好的安全性,在具体并发症方面尚需更多高质量文献进一步验证。