自制可回收下腔静脉滤器预防急性肺栓塞的实验研究

目的 探讨一种新型可回收下腔静脉滤器预防急性肺栓塞的有效性、安全性.方法 12只犬制备成髂股深静脉血栓模型,分为滤器组(实验组)与无滤器组(对照组),每组6只.滤器组在深静脉血栓脱落前于对侧股静脉置入下腔静脉滤器,其后使血栓脱落;对照组直接使血栓脱落即形成肺动脉栓塞.通过血栓脱落前后的肺动脉造影、肺动脉测压以及动脉血氧饱和度测定评价滤器的血栓捕获性能.结果 滤器组均成功捕获脱落的深静脉血栓,无一例发生肺动脉栓塞,8 h后滤器均能成功回收;而对照组在推注血栓后均发生了肺动脉栓塞.结论 自制可回收下腔静脉滤器能有效预防下肢深静脉急性血栓脱落引起的肺动脉栓塞,其置入和回收简便.     

生物可降解腔静脉滤器的制备及其性能研究

目的 对采用左旋聚乳酸(PLLA)制备生物可降解腔静脉滤器(BVCF)进行研究,并评估其机械力学性能、可输送性能、捕获血栓性能及其生物相容性.方法 利用三维设计软件设计BVCF外形,采用分子量为100 000 U的PLLA制作BVCF,通过体外实验,对其主要性能进行测试.采用中华小型猪12只,随机分为4组(每组3只),第1～3组为实验组,第4组为对照组.将9枚BVCF置入第1～3组实验小型猪下腔静脉内,1周后对所有小型猪行血栓注入实验.每组的3只小型猪下腔静脉分别注入2、5和8条血栓.注入血栓后l、6、12周行影像检查,观察滤器情况及小型猪肺动脉栓塞情况.每次影像检查后,牺牲1组实验组动物行病理检查.结果 制备出一种带中心线型的可降解滤器,通过体外实验测试滤器径向支撑力1.6N,能够捕获直径＞5 mm的栓子,易于释放.通过动物实验证实该滤器能够捕获注入的致命性栓子,9只实验组小型猪均存活,其中2只栓子注入过程中出现轻度呼吸、心率加快；对照组小型猪注入血栓后不同程度地出现呼吸频率加快、气促等症状,注入8条血栓的小型猪,在血栓注入后当天死亡.术后影像及病理检查显示,实验组出现症状的小型猪发生周围性肺动脉栓塞,对照组死亡小型猪发生中央性肺动脉栓塞.显微镜下显示滤器置入术后1周,BVCF侧支部分被内膜覆盖；6周后完全被内膜覆盖,血管壁结构正常,未见明显炎性细胞浸润；术后12周BVCF侧支内膜情况无明显变化,滤器侧支部分降解.结论 BVCF具有良好的机械强度和可输送性能,对致命性大栓子有较高的捕获率,并具有良好的生物相容性,但其降解性能尚需进一步研究.     

下腔静脉Günther Tulip滤器倾斜发生机制的体外研究

目的 采用体外下腔静脉(IVC)模型探讨经股静脉Günther Tulip滤器(GTF)置入发生倾斜的机制.方法 体外IVC模型由悬吊于透明、分叉玻璃管中的1支直径25 mm、长10 cm涤纶人工血管及2支直径10 mm、长10 cm涤纶人工血管构成.经股静脉GTF置入分为两组:右直组GRS)(n ＝ 100)和左直...     

自制下腔静脉支架式滤器安全性的动物实验研究

目的探讨自制下腔静脉支架式滤器(VCSF)置入术预防肺动脉栓塞的安全性。方法用镍钛合金丝和不锈钢金属杆制成梭形伞状滤器;10条犬制备成下腔静脉滤器留置模型,按VCSF留置时间(2、3、4、5和6周)分为5个实验组,每组2条。经股静脉VCSF置入下腔静脉后,分别饲养至2～6周时,再造影观察下腔静脉血流通畅情况,并将VCSF的金属杆取出,使临时滤器改变成永久支架,评价滤器部件回收操作难易和滤过伞松开后支撑丝贴壁情况。最后处死实验动物取材,肉眼观察和病理检查滤器置入处下腔静脉内膜增生情况。结果10枚VCSF均成功置入。置入后2～6周时造影显示下腔静脉血流畅通,滤器无倾斜和移位;金属杆取出顺利,10枚VCSF两端滤过伞均可松开成为腔静脉支架,贴壁良好。标本肉眼观察可见滤器倒刺露出腔静脉外膜,未见腹膜后出血和滤器内血栓形成;VCSF置入2周时可见新生内膜覆盖滤器编织网,显微镜下3～4周时内膜轻度增生,5～6周时内膜中度增生。结论自制下腔静脉支架式滤器可根据血栓治疗需要较长时间地置放于体内,不妨碍下腔静脉血流;滤器定位稳定,其置入和回收部件操作简便可行。     

Günther Tulip可回收式腔静脉滤器在急性下肢深静脉血栓形成介入治疗中的作用

目的 探讨G(u)nther Tulip可同收式腔静脉滤器在下肢深静脉血栓形成介入治疗中的应用效果及操作技术.方法 2007年9月至2008年4月于我院就治的急性下肢深静脉血栓形成患者36例,发病时间1～12 h,发病诱因包括术后及骨折后卧床18例、产后5例、无明显诱因13例;合并肺动脉栓塞12例.症状表现为患肢肿胀(患肢大腿周径比健侧大3～10 cm)、疼痛、皮肤晕青紫色或苍白,皮温升高或正常,合并肺动脉栓塞者表现为呼吸困难、胸痛、咯血等.分别经股静脉或经右颈内静脉置入G(u)nther Tulip可回收式腔静脉滤器后,均行静脉内置管溶栓治疗.术后45～75 d经血管超声及血管造影复查证实下肢静脉及肺动脉内无新鲜或游离血栓后,经右颈内静脉入路行G(u)nther Tulip腔静脉滤器取出术,复查下腔静脉造影.术后给予抗凝、抗炎治疗3～5d.随访4～10个月.结果 共置入G(u)nther Tulip可回收式腔静脉滤器36枚,均一次性释放成功,释放过程平均耗时1.5 min(0.5～5 min),释放过程中滤器弹跳幅度小于2 mm,1例滤器置入时倾斜25°,滤器置入后未出现新发生肺动脉栓塞的临床表现.12例患者于术后45～75d行G(u)nther Tulip腔静脉滤器取出术,均一次性回收成功,同收过程耗时4.4 min(2～15 min),下腔静脉造影复查未见管壁穿孔及破裂征象.其余24例患者未行滤器取出术,随访期间未出现肺动脉栓塞及下腔静脉闭塞的临床表现.结论 G(u)nther Tulip可回收式腔静脉滤器具有释放定位准确、捕获血栓能力较高、可取出时间期限长(溶栓治疗时间窗长)、回收成功率高等优点,在下肢深静脉血栓介入治疗中的临床效果良好,技术操作成功率较高.     

Aegisy可回收腔静脉滤器的临床应用与观察

目的探讨hegisy可回收腔静脉滤器预防肺动脉栓塞的临床应用价值。方法对32例急性或亚急性下肢深静脉血栓形成（deep vein thrombosis,DVT）和（或）肺动脉栓塞（pulmonary embolism,PrO的患者经健侧股静脉置入滤器,经用药物或手术治疗,观察有无肺动脉栓塞症状及有无肺动脉栓塞症状加重情况,滤器有无形态及位置变化。结果下腔静脉滤器置入全部成功,下肢深静脉血栓形成患者治疗后效果良好,无症状性肺动脉栓塞发生,置入滤器平均（14．0±2．0）天,取出可回收滤器捕捉血栓24例,占75％。结论可回收下腔静脉滤器预防肺动脉栓塞的疗效确切,具有较高的临床应用价值。     

自制下腔静脉滤器的体外实验

目的 评估自制的下腔静脉滤器(DDIVCF)捕获猪血栓子的效果及其定位稳定性.方法 ①将DDIVCF滤器和进口Antheor临时性下腔静脉滤器分别置入于直径为20和25 mm的下腔静脉(IVC)血液循环模型中,观察模型处于水平位时滤器对3 mm×20 mm,3 mm×30 mm,6 mm×20 mm,6 mm×30 mm 4种大小不同的猪血栓子的捕获效果,并计算其捕获率.②测量滤器捕获大量6 mm×30 mm栓子后相对位移的距离,观察滤器的定位稳定性.结果 ①DDIVCF滤器在直径20和25 mm的IVC模型中对4种猪血栓子的捕获率分别为34%,56%,82%,94%和26%,38%,56%,86%;Antheor的捕获率分别为54%,64%,86%,96%和38%,44%,68%,90%.对3 mm×30 mm,6 mm×20 mm,6 mm×30 mm猪血栓子的捕获率两者间差异无统计学意义(P＞0.05).②在直径20和25 mm的IVC模型中DDIVCF滤器捕获猪血栓子后相对位移距离分别为(0.6±0.3)cm和(1.0±0.1)cm.Antheor的相对位移距离分别为(0.4±0.1)cm和(0.8±0.3)cm,两者差异无统计学意义(P＞0.05).结论 DDIVCF在体外模型实验中具有较高的血栓捕获率和定位稳定性,可与进口Antheor临时性下腔静脉滤器媲美,其体内应用情况尚需进一步动物实验研究.     

可回收腔静脉滤器在下肢深静脉血栓导管抽吸去栓术治疗中的应用

目的：探讨国产可回收腔静脉滤器在急性下肢深静脉血栓形成经皮导管抽吸去栓术中的应用价值。方法：29例左侧急性下肢深静脉血栓形成,预先置入可回收腔静脉滤器,随后行导管抽吸去栓,最后对左侧髂总静脉行血管成形术。结果：29例中27例回收,19例截获大块血栓,所有病例均未发生肺栓塞及与滤器相关的并发症。结论：行经皮导管抽吸去栓术预先置入可回收性滤器,是一种安全有效的必要措施。     

下腔静脉可回收滤器置入预防肺栓塞

目的:评价可回收下腔静脉滤器在下肢深静脉血栓患者中预防肺栓塞效果和安全性。方法:34例下肢深静脉血栓患者全部行下腔静脉滤器置入术,其中12例采用永久性Trap Ease Filter(TEF),16例采用可回收性OptEaseTMFilter(TEF),6例采用可回收性Gunther Tulip Filter(GTF)滤器,滤器均置于肾静脉水平以下的下腔静脉中。结果:34例滤器均经股静脉穿刺置入,16例可回收性OptEaseTMFilter中12例2周后经股静脉取出。6例可回收性Gunther Tulip Filter(GTF)滤器两周后经右颈内静脉取出。手术成功率100%。随访30例(随访时间:2~28个月),12例永久滤器病人中有1例出现倾斜,但角度小于15℃,1例下腔静脉血栓形成,术中术后未出现滤器移位,穿破管壁和肺栓塞。结论:可回收性下腔静脉滤器是预防肺栓塞安全、有效的方法之一,且并发症少。     

急性DVT股静脉取栓治疗32例

目的总结急性期单侧下肢深静脉血栓形成股静脉取栓的治疗效果及应用Aegisy可回收下腔静脉滤器预防肺动脉栓塞的效果。方法选择32例急性期单侧下肢深静脉血栓形成患者,通过放置Aegisy可回收下腔静脉滤器后,行股静脉切开取栓,于术后12～16d取出滤器。术后维持抗凝治疗1年。结果32例患者滤器成功置入,股静脉取栓顺利;术后30例成功取出滤器,取出滤器中有20例捕捉到血栓。全组治疗过程中无肺动脉栓塞发生,肢体肿胀明显缓解;随访1—8个月,彩色多普勒超声检查未见下肢深静脉血栓复发。结论股静脉取栓是治疗急性期下肢深静脉血栓形成的有效手段,术中放置可回收下腔静脉滤器能有效预防肺动脉栓塞发生,滤器的置入和取出安全、可行。     

Insertion and recovery of a new retrievable vena caval filter. Work in progress

A new retrievable inferior vena cava (IVC) filter was tested in nine pigs. Insertion was through a 14 French sheath using both the femoral and jugular approaches. All insertions were successful, and there was a 100% postinsertion IVC patency rate (8/8 pigs at one week and 1/1 pig at one month). Addition of an apical hook to the filter design allowed transjugular retrieval of two filters at one week postinsertion. Three of nine filters migrated to the upper IVC. The filter's design allows paraxial blood flow despite trapped thrombus and inhibits filter tilting. In vitro, the filter captured 95% to 100% of 5 X 5 mm clots. If problems with migration can be solved, the new filter may provide effective short- and long-term prophylaxis against pulmonary embolism.     

In vitro evaluation of a retrievable low-profile nitinol vena cava filter

PURPOSE: To evaluate the clot-trapping ability, stability, and migration of a new low-profile, retrievable inferior vena cava (IVC) filter in an in-vitro model. MATERIALS AND METHODS: The SafeFlo IVC filter consists of two superelastic nitinol wires that form a double-ring platform and spiral filter. The filter is collapsed into a 5-6-F catheter and delivered into the IVC model. The in-vitro model closely simulates the physical parameters of flow in the human IVC. Human blood clots of 2-mm and 4-mm diameters and 3-cm lengths were injected into the flow system in sets of five clots. Filter delivery and retrieval were performed in every series. Filtration was evaluated in IVC models of 20-mm and 24-mm lumen diameter in vertical and horizontal positions. Stability and migration of the filter were evaluated by direct vision of maintenance of position and shape before and after clot trapping. RESULTS: Filter delivery and retrieval were straightforward and repeatable in a total of 20 procedures. The filters maintained shape and position throughout the study. A total of 248 clots were injected and 225 (90.7%) were trapped. The individual tests in horizontal and vertical positions with either clot size demonstrated trapping rates of 85.7%-97.1%. CONCLUSIONS: The SafeFlo IVC filter is a stable and effective filter in an in-vitro model. The filter design is amenable to simple delivery and retrieval.     

Fracture and migration of a suprarenal inferior vena cava filter in a pregnant patient

Placement of retrievable inferior vena cava (IVC) filters as prophylaxis for pulmonary embolism (PE) is an increasingly attractive option for patients who require temporary IVC filtration. However, experience thus far with retrievable filters in pregnant patients is limited. This report describes a suprarenally placed Recovery IVC filter in a pregnant woman with PE despite therapeutic anticoagulation. After failed induction of labor and uneventful cesarean section, the patient returned for filter retrieval 167 days after initial placement. Fracture and inferior migration of the filter was observed, and subsequent attempts at filter retrieval were unsuccessful.     

Percutaneous Retrieval of the Tulip Vena Cava Filter: Feasibility, Short- and Long-Term Changes. An Experimental Study in Dogs

Purpose: To evaluate experimentally the retrievability of the Tulip inferior vena cava (IVC) filter in an in vivo study. Changes which accompany venous healing after filter retrieval were investigated. Methods: In 12 dogs, 23 filters were inserted percutaneously into the lumbar and intrahepatic segments of the IVC. Two weeks (n = 21 filters) or 3 weeks (n = 2 filters) after insertion, filter retrieval was attempted through an 11 Fr coaxial retrieval sheath system placed via the jugular vein. Follow-up studies before and after filter retrieval included cavography, computed tomography and intravascular ultrasound of the IVC. Seven dogs were killed immediately after filter retrieval to confirm short-term changes of the IVC, and 5 dogs were killed 6 months after filter retraction to evaluate long-term changes of the IVC related to filter retrieval. Post-mortem examinations and histologic specimens of the IVC were obtained to evaluate caval wall abnormalities secondary to filter removal. Results: All but one filter were successfully retrieved 2 weeks post-implantation. However, 3 weeks after insertion, filter retrieval was impossible. There were no complications caused by filter extraction. Follow-up studies after filter retrieval revealed no significant changes in the integrity, morphology or composition of the IVC and pericaval tissue. Histologic examination 6 months after filter retrieval revealed only flimsy fibrotic intimal plaques at the sites of former hook insertion. Conclusion: The Tulip filter allows percutaneous insertion and retrieval up to 14 days after insertion, suggesting that it may be useful for either permanent or temporary prophylaxis against pulmonary embolism.     

Inferior vena cava filters: in vitro comparison of clot trapping and flow dynamics

Using a flow model that simulated the inferior vena cava (IVC), the authors conducted an in vitro comparison of the Mobin-Uddin (MU), Kimray-Greenfield (KG), Amplatz spider (A), Günther basket (G), Simon nitinol (SN), and bird's nest (BN) filters. The following parameters were evaluated: clot-trapping capacity and flow dynamics, which included measurements of pressure gradients across filters and assessment of flow patterns. The MU, A, G, SN, and BN filters trapped an average of 80%-100% of small clots and 100% of large clots. The KG filter, in a central position, trapped 0%-10% of small clots and 60%-100% of larger clots. In the eccentric position, the KG filter trapped only 20% of all clots. The BN and SN filters showed the least flow turbulence. Moderate turbulence was observed with the G and KG filters, while the MU and A filters showed marked turbulence. The current standard KG filter allowed the passage of small and large clots. When specific parameters were considered--such as clot-trapping capacity and flow-dynamic performance--the BN, SN, and G IVC filters were superior to the other filters that were tested.     

The Simon nitinol inferior vena cava filter: preliminary experience in the UK.

The Simon nitinol filter is one of a new range of inferior vena cava filters designed for percutaneous placement. It employs a thermal memory alloy allowing it to be introduced in a straight form via a 9F sheath when cool but transforming instantly into its predetermined filter shape at body temperature. It was placed rapidly and successfully in six patients via a femoral approach and one patient via an antecubital vein. The only complication was an asymptomatic IVC obstruction in one patient.     

The DENALI Trial: An Interim Analysis of a Prospective,Multicenter Study of the Denali Retrievable Inferior Vena Cava Filter

PurposeTo assess safety and effectiveness of a nitinol retrievable inferior vena cava (IVC) filter in patients who require caval interruption to protect against pulmonary embolism (PE).Materials and MethodsTwo hundred patients with temporary indications for an IVC filter were enrolled in this prospective, multicenter clinical study. Patients undergoing filter implantation were to be followed for 2 years or for 30 days after filter retrieval. At the time of the present interim report, all 200 patients had been enrolled in the study, and 160 had undergone a retrieval attempt or been followed to 6 months with their filter in place. Primary study endpoints included technical and clinical success of filter placement and retrieval. Patients were also evaluated for recurrent PE, new or worsening deep vein thrombosis, and filter migration, fracture, penetration, and tilt.ResultsClinical success of placement was achieved in 94.5% of patients (172 of 182), with a one-sided lower limit of the 95% confidence interval of 90.1%. Technical success rate of filter placement was 99.5%. Technical success rate of retrieval was 97.3%; 108 filters were retrieved in 111 attempts. In two cases, the filter apex could not be engaged with a snare, and one device was engaged but could not be removed. Filter retrievals occurred at a mean indwell time of 165 days (range, 5–632 d). There were no instances of filter fracture, migration, or tilt greater than 15° at the time of retrieval or 6-month follow-up.ConclusionsIn this interim report, the nitinol retrievable IVC filter provided protection against pulmonary embolism, and the device could be retrieved with a low rate of complications.     

Inferior vena cava filter removal after 317-day implantation

A Günther Tulip inferior vena cava (IVC) filter was placed prophylactically in a 22-year-old trauma victim with spinal injuries. Attempts to retrieve the filter at 21 and 25 days after placement were aborted as a result of clot trapped in the filter. Despite the possible risk of an IVC laceration, a third attempt was made 317 days after placement in view of the young age of the patient. The filter started collapsing into the retrieval sheath but could not easily be separated from the IVC. During attempted redeployment, the filter would not reopen. The filter was ultimately retrieved with use of additional force. A mild stenosis of the IVC was noted immediately after retrieval. However, the IVC returned to its preretrieval diameter as seen on a 3-month follow-up venogram.     

Long-term optional retrievability of a new inferior vena cava filter in an ovine model

Long-term retrievability of a new optional retrieval inferior vena cava (IVC) filter composed of a modified square stent and a modified Günther Tulip filter was tested in eight sheep. Eleven filters were placed into the IVC and eight were successfully retrieved 3-5 months after implantation. Incorporation of the filter struts into the IVC wall prevented its retrieval in three sheep at 3, 4, and 5 months after placement.     

Use of the Bird's Nest filter in oversized inferior venae cavae.

An inferior vena cava (IVC) diameter of greater than 28 mm has been considered a contraindication to the intracaval placement of Greenfield, LG-Medical (LGM), and Simon nitinol filters, necessitating biiliac placement of these devices. With the Bird's Nest filter (BNF), the maximum span of the struts, which immobilize the device, is 60 mm; this allows the placement of the BNF in an oversized IVC having a diameter of greater than 28 mm. Over a 44-month period, 799 IVC filters (547 BNF, 136 Greenfield filters, and 116 LGM filters) were inserted. BNFs were placed in 18 patients (2.3%) with an oversized IVC (diameter range, 29-42 mm); all filters were placed via the femoral route. Patient records were reviewed to determine if problems were associated with filter insertion (including insertion site femoral vein thrombosis) and to determine the prevalence of filter migration, caval thrombosis, and new or recurrent pulmonary emboli (PE) after insertion. No difficulties were encountered during insertion. There was no documented case of device migration, caval thrombosis, or clinically apparent new or recurrent PE. The data suggest that the BNF is the filtering device of choice in patients with an oversized IVC.