Endovascular treatment of experimental aneurysms in rabbits using Guglielmi detachable coils – a feasibility study

The Guglielmi detachable coil (GDC) has been generally accepted for treatment of intracranial aneurysms. Preclinical testing of new coil developments requires animal models of aneurysms which imitate human aneurysms in size, configuration and neck morphology. We assessed in detail the technical requirements and steps for transfemoral treatment of experimentally induced aneurysms at the top of the brachiocephalic trunk (TBC) in rabbits. We created aneurysms in five rabbits by distal ligation and intraluminal incubation of the right common carotid artery with elastase. All animals were treated successfully 2-3 weeks after induction of the aneurysm, with dense packing of the coils. No complications related to the procedures occurred. The study demonstrates that our animal model can be a suitable method for testing the biocompatibility and occlusion rate of new embolic materials.     

Combined use of stents and coils to treat experimental wide-necked carotid aneurysms: preliminary results.

PURPOSETo develop a new technique to treat wide-necked side-wall aneurysms, combining the implantation of intraarterial stents with the endosaccular placement of coils.METHODSBilateral side-wall aneurysms were surgically created on the carotid arteries of four dogs. In each animal, Guglielmi detachable coils were introduced into one of the aneurysms after implantation of a balloon-expandable Strecker stent within the parent artery, adjacent to the aneurysm orifice. The contralateral aneurysms were treated with coils alone.RESULTSIn two dogs, one of the stented and both nonstented aneurysms remained partially open for 4 weeks after subtotal packing with coils. In another two dogs, tight aneurysm packing with coils resulted in complete occlusion of all four aneurysms. Bulging of the coil mass resulted in 30% to 75% narrowing of the nonstented parent arteries. At 4 and 5 weeks, significant stenosis resulting from reactive hyperplasia was observed in all stented carotid arteries.CONCLUSIONBased on these preliminary results, we conclude that Guglielmi detachable coils can be introduced into an aneurysm cavity through Strecker stents. The stents allow tighter packing of wide-necked aneurysms by preventing coils from migrating or bulging into the parent arteries.     

Neuroform颅内支架辅助栓塞宽颈颅内动脉瘤的初步经验

目的　报道我科使用Neuroform支架辅助可脱式弹簧圈栓塞宽颈脑动脉瘤的初步经验。方法　 2 2例 2 4枚宽颈颅内动脉瘤采用Neuroform支架和弹簧圈进行栓塞 ,其中急性破裂动脉瘤 19枚、未破裂动脉瘤 5枚。结果　支架均成功地释放 ,支架置入后的造影未发现有瘤内造影剂滞留的血流动力学改变。 10 0 %闭塞动脉瘤 18枚 ,90 %以上闭塞 5枚 ,1枚伴发的未破裂小型宽颈动脉瘤在支架置入后微导管无法超选 ,载瘤动脉均通畅。有 2枚动脉瘤虽有支架阻挡 ,但仍有部分弹簧圈畔进入载瘤动脉。所有患者没有出现与支架置入有关的症状性缺血性并发症。 17例造影随访中 ,有 1例在 3个月复查时发现再通 ,进行 2次栓塞完全闭塞动脉瘤 ,其余未见复发 ,结论　Neuroform颅内支架使用安全有效 ,适合于宽颈颅内动脉瘤的支架辅助弹簧圈栓塞 ,特别适合于迂曲的脑血管 ;其径向支撑力较差 ,在输送微导管时应防止其移位 ;其支架网眼较大 ,对血流动力学改变不明显 ,致密填塞是重要的 ,在输送弹簧圈时仍应防止弹簧圈畔进入载瘤动脉 ;术前、术后抗血小板药物的应用以及术后严格的系列造影随访是必要的。     

血管内支架治疗颅内动脉瘤

目的：探索使用血管内支架及血管内支架结合电解可脱卸弹簧圈（Guglielmi detachable coil,GDC)治疗颅内梭形及宽颈动脉瘤的可能性。方法：3例椎动脉颅内段梭形动脉瘤及6例宽颈动脉瘤,首先将冠脉支架跨动脉瘤颈放置,通过支架的网孔将微导管送入动脉瘤腔,填入GDC。结果：7例动脉瘤致密堵塞,2例大部堵塞,载瘤动脉通畅,临床效果优良。结论：联合使用支架及微弹簧圈是治疗颅内梭形及宽颈动脉瘤可选择的有效方法之一。     

Long-term angiographic and histopathologic findings in experimental aneurysms of the carotid bifurcation embolized with platinum and tungsten coils.

PURPOSETo evaluate the long-term outcome of endovascular occlusion of arterial aneurysms effected with metal coils.METHODSMicrosurgical methods were used to produce carotid bifurcation aneurysms in 20 rabbits and the radiologic and histologic changes were examined. Eight of these aneurysms were occluded with electrically detachable platinum coils (Guglielmi detachable coils [GDCs] and nine were treated with mechanically detachable tungsten coils (mechanical detachable system [MDS]). Three aneurysms remained untreated and served as controls. One animal died of embolic complications 12 hours after endovascular treatment. After observation periods of 3 to 6 months, the remaining animals were examined by intraarterial digital subtraction angiography and subsequent fixation and light and electron microscopy.RESULTSLarge open spaces without signs of thrombosis were found between the loops of the coil baskets in 12 aneurysms (six treated with GDCs and six treated with MDS) regardless of the observation period. In very densely packed aneurysms (four cases with complete occlusion as determined by angiographic criteria), the coil surfaces were for the most part covered by thin cell layers; however, complete endothelialization was never seen. In aneurysms with an initial partial occlusion of 70% to 90%, coil compaction and/or recanalization was a consistent finding. A comparison of the radiologic findings with the histologic aspect revealed that the degree of occlusion was often overrated on the radiographs (in eight of 17 cases). In general, the fibrous tissue reaction appeared to be slightly more pronounced in aneurysms occluded with tungsten coils.CONCLUSIONSPlatinum and tungsten coils were not always effective in causing endoluminal thrombosis leading to long-term occlusion by organized thrombus.     

Neuroform自膨式支架结合弹簧圈栓塞颅内宽颈动脉瘤

目的 探讨Neuroform自膨式支架结合弹簧圈治疗颅内宽颈动脉瘤的安全性、术中并发症、近中期疗效和应用前景.方法 采用Neuroform支架结合弹簧圈栓塞治疗25例27枚颅内宽颈动脉瘤.动脉瘤位于颈内动脉海绵窦段3枚,眼动脉1枚,后交通动脉18枚,前交通动脉2枚,大脑中动脉M1段1枚,大脑中动脉分义部1枚,基底动脉干1枚.其巾2例患者为多发动脉瘤,绝对宽颈(瘤颈>4 mm)动脉瘤21枚,相对宽颈6枚,瘤颈/瘤体均大于0.7.结果 4枚采用NeuroformⅡ代自膨式支架结合弹簧圈栓塞治疗,其余均采用NeuroformⅢ代支架结合弹簧罔栓塞治疗.25例26枚支架均成功到位释放,1例多发动脉瘤患者置入2枚支架.7枚动脉瘤完全栓塞(100%),9枚几乎完全栓寒(95%～99%),11枚不完全栓塞(95%以下).2例术中出血;2例术中支架内血栓形成,其中1例术后遗留肢体偏瘫,另1例死亡;1例术中弹簧圈尾端从支架网孔突入颈内动脉,术后出现一过性脑缺血表现,其余患者均恢复良好出院.临床随访24例,随访期1～32个月,平均10.8个月.3例术后3～6个月血管造影随访,其中1例后交通动脉瘤患者同侧大脑前动脉闭塞,大脑中动脉主干血栓形成;另2例原有瘤颈残留者无变化.结论 在栓塞颅内宽颈动脉瘤时应用Neurolform自膨式支架结合弹簧圈技术,使弹簧圈无法突入载瘤动脉,可提高柃塞致密度,安全、疗效好.     

颅内自膨胀支架结合弹簧圈治疗脑动脉瘤

目的　报道采用自膨胀颅内专用支架 (Neuroform支架 )结合弹簧圈栓塞治疗颅内宽颈动脉瘤 ,初步探讨该支架的特点、短期疗效及应用前景。方法　采用Neuroform支架结合弹簧圈栓塞治疗 32例 34枚颅内宽颈动脉瘤。颈内动脉海绵窦段 3例 ,眼动脉 3例 ,后交通动脉 8例 ,前交通动脉 3例 ,大脑中动脉分叉部 5例 ,椎动脉 6例 ,基底动脉顶端 1例 ,基底动脉干 2例 ,大脑前动脉A3段 1例 ,多发动脉瘤 2例。通过Renegade微导管释放Neuroform支架覆盖动脉瘤瘤颈 ,预先将另一微导管置入动脉瘤腔或将微导管通过支架网孔以弹簧圈栓塞动脉瘤。结果　 31例 34个支架成功到位释放 ,1例基底动脉顶端动脉瘤因支架无法通过狭窄的大脑后动脉而改用BX支架。 3例 1次各置入 2枚支架。 2 4例致密栓塞 ,6例瘤颈残留 ,2例部分栓塞。 1例术中发生支架内血栓 ,死亡 1例 ,其余患者均恢复良好出院。临床随访 30例 ,随访期 1～ 6个月 ,平均 4 .7个月 ,无再出血及血栓栓塞症状发生。 1 1例术后 3个月血管造影随访 :7例致密栓塞的动脉瘤均未显影 ;4例瘤颈残留者 ,2例无变化 ;2例原有瘤颈残留未再显影。结论　Neuroform支架技术上容易操控 ,顺应性好 ,安全性高 ,可以到达颅内较远端的血管 ,大大扩展了支架技术治疗颅内血管病变的应用范围 ,近期     

Single-center experience of cerecyte coils in the treatment of intracranial aneurysms: initial experience and early follow-up results

BACKGROUND AND PURPOSE: Endovascular treatment of intracranial aneurysms using platinum coils is effective, but uncommonly aneurysms recur. New-generation coils, such as Cerecyte, aim to address this problem. This study examines the safety and efficacy of these coils in the treatment of a cohort of ruptured and unruptured aneurysmsMATERIALS AND METHODS: Sixty-seven patients with 68 aneurysms were included in the study. Of these, 51 were treated exclusively with the new polyglycolic acid (PGA)-containing coils, and 17 were treated with a combination of new PGA-containing and other coils. Initial and follow-up angiograms were graded according to the 3-point scale of occlusion. Follow-up angiography was available in 46 cases at 6 months. Based on occlusion grading at initial and follow-up angiography, aneurysms were classified into stable, improved, and worsened (recanalized) groups.RESULTS: Of the exclusive new-coil cohort, 36 cases (70.6%) were initially completely occluded (grade 1), 12 (23.5%) showed filling at the neck (grade 2), and 3 (5.9%) showed contrast within the neck and sac (grade 3). Analysis of the follow-up angiograms showed 24 (70.6%) had stable occlusion, 3 (8.8%) had improved occlusion, and 7 (20.6%) had worsening occlusion. Data for cases treated with new PGA-containing coils together with bare platinum coils were also analyzed separately. Intraprocedural adverse events were noted in 4 cases (7.8%), but there were no clinical sequelae. There were no rebleeds in the follow-up period.CONCLUSION: New PGA-containing coils show no excess in procedural and periprocedural complications over bare platinum coils, and the recanalization rate is comparable with bare platinum coils in the short term.

We report the early results of 68 aneurysms treated with PGA-modified coils. Cerecyte (Micrus, Sunnyvale, Calif) coils incorporate a strand of polyglycolic acid (PGA) polymer that has been shown to accelerate aneurysm fibrosis and neointima formation in animal studies.¹ Endovascular coiling has been the treatment of choice for most intracranial aneurysms since the publication of the International Subarachnoid Aneurysm Trial (ISAT). This showed a significant decrease in immediate morbidity and mortality compared with neurosurgical clipping in those aneurysms previously deemed suitable for either management. Follow-up of patients treated with endovascular coiling has, however, shown that a minority of cases undergo compaction of the coil ball and recanalization or regrowth of the treated aneurysm. These patients are at risk of recurrent subarachnoid hemorrhage. To combat the risk of recurrence, new devices and technologies have been developed. These include the use of nondetachable balloons and expandable stents to allow improved treatment of wide-necked aneurysms and, more recently, new coils. These coils incorporate a polymer with properties that are supposed to improve aneurysm occlusion.     

血管内支架结合电解可脱卸弹簧圈治疗犬颈动脉宽颈动脉瘤的实验研究

目的 通过支架植入及结合电解可脱卸弹簧圈治疗犬颈动脉宽颈侧壁囊性动脉瘤实验研究评价动脉瘤栓塞后的血流动力学及组织学改变。方法 于6只健康犬双侧颈动脉分别建立宽颈侧壁动脉瘤，一侧单纯支架植入，对侧行支架植入结合弹簧圈栓塞。行血管超声和血管造影检查，并观察大体解剖及电镜检查：结果单纯支架植入的动脉瘤内无血栓形成，瘤颈处新生内膜生长较慢，而支架结合弹簧圈治疗的动脉瘤内很快形成血栓，新生内膜能完全覆盖动脉瘤颈。结论 血管内支架结合电解可脱卸弹簧圈治疗宽颈动脉瘤不但可以降低动脉瘤再破裂的风险，而且能达到动脉瘤解剖学治愈。     

Treatment of wide-necked intracranial aneurysms with a self-expanding stent system: initial clinical experience

BACKGROUND AND PURPOSE: Currently available stents for intracranial use usually are balloon-expandable coronary stents that carry the risk of damaging a dysplastic segment of the artery, with potential vessel rupture. We assessed the technical feasibility and efficacy of the combined application of a flexible, self-expanding neurovascular stent and detachable coils in the management of wide-necked intracranial aneurysms in humans. METHODS: Four consecutive patients with a wide-necked intracranial aneurysm were treated with a combined approach that consisted of delivery of a flexible self-expanding neurovascular stent through a microcather to cover the neck of the aneurysm and subsequent filling of the aneurysm with coils through the stent interstices. The aneurysms were located at the internal carotid artery (n=2) and the basilar tip encroaching the P1 segment (n=2). Previous attempts with conventional endosaccular coil packing alone failed in all cases. RESULTS: Stent placement in the desired position with complete or nearly complete occlusion of the aneurysms was feasible in all patients. In one patient, aneurysm perforation with the microcatheter occurred and necessitated ventricular drainage, which led to a large parenchymal and intraventricular hemorrhage because of the strong anticoagulation regimen. Six-month follow-up demonstrated no focal neurologic sequelae in any of the patients, except slight memory dysfunction in the patient with bleeding. CONCLUSION: Preliminary data demonstrate that this extremely flexible stent is technically easy to deploy and can be easily and safely maneuvered through severely tortuous vessels, enabling the treatment of intracranial wide-necked aneurysms. The combination of endovascular reconstruction of the parent vessel with use of a self-expanding stent followed by coil embolization offers a promising therapeutic alternative for wide-necked aneurysms not amenable to coil embolization alone. Although immediate angiographic results are promising, long-term angiographic and clinical follow-up is essential to determine permanent vessel patency and aneurysm occlusion rate.     

小脑后下动脉瘤血管内栓塞治疗的初步临床研究

目的 探讨小脑后下动脉(PICA)瘤栓塞治疗的方法及效果.方法 回顾性分析21例PICA瘤经血管内栓塞治疗的临床资料,根据DSA资料估计动脉瘤的解削分段.采取单纯弹簧圈栓塞8例、单纯液体胶栓塞5例、弹簧圈联合液体胶栓塞2例、支架辅助弹簧圈栓塞2例、球囊辅助弹簧圈PICA闭塞4例,用格拉斯哥预后(GOS)评分评估疗效.结果 单纯弹簧圈致密栓塞5例,90%以上栓塞2例,85%栓寒1例;单纯液体胶栓塞的5例及弹簧圈联合液体胶栓塞的2例均达到致密栓塞;支架辅助弹簧圈栓塞的2例90%以上栓塞;球囊辅助弹簧圈完全闭塞载瘤动脉3例,90%以上栓塞1例.术后脑干穿支动脉闭塞导致死亡1例,术后1周新发神经功能障碍1例,其余未见再出血及小脑损害症状.术后随访6～60个月,平均(22±8)个月.COS评分Ⅰ级1例,Ⅱ级1例,Ⅲ级2例,Ⅳ级5例,Ⅴ级12例.结论 根据PICA瘤的解剖分段选择不同的栓塞方法,可取得良好的治疗效果.     

支架结合弹簧圈治疗颅内宽颈动脉瘤急性破裂的可行性和安全性

目的　总结血管内支架结合电解可脱卸弹簧圈 (GDC)治疗颅内宽颈动脉瘤急性破裂的临床体会 ,对其可行性和安全性进行初步探讨。方法　 5 7例急性破裂宽颈动脉瘤 ,均先植入冠脉支架覆盖动脉瘤颈 ,再将微导管通过支架网孔超选进入动脉瘤腔内填塞GDC。结果　 1例因血管扭曲不能植入支架 ,5 6例成功 ,均达到 90 %以上栓塞 ,载瘤动脉通畅 ,所有患者无神经功能障碍出现。结论　血管内支架植入结合GDC填塞是治疗急性破裂宽颈动脉瘤的安全、可行的方法     

一期血管内栓塞治疗颅内多发动脉瘤的临床研究

目的总结和探讨一期血管内栓塞治疗颅内多发动脉瘤的方法及疗效。方法对2005年9月-2010年6月收治的18例颅内多发动脉瘤患者的44个动脉瘤行一期血管内栓塞治疗,其中采用单纯弹簧圈栓塞动脉瘤32个,颅内支架(LEO支架或En-terprise支架)辅助弹簧圈栓塞宽颈动脉瘤12个。术后3～12个月进行临床和影像学随访。结果全部病例栓塞成功。12枚支架到位满意。38个动脉瘤完全闭塞,5个闭塞95%以上,1个闭塞95%以下。无手术并发症,术后患者均恢复良好,临床随访3～12个月无动脉瘤再出血或脑血栓形成,其中数字减影血管造影(DSA)随访9例无动脉瘤复发及支架狭窄。结论一期血管内栓塞是治疗颅内多发动脉瘤安全有效的方法,但其长期疗效仍需进一步观察。     

Long-term results with Matrix coils vs. GDC: an angiographic and histopathological comparison

INTRODUCTION: The aim of the study was to compare standard platinum Guglielmi detachable coils (GDC) with coated platinum coils (Matrix; both Boston Scientific, Fremont, CA) regarding handling, complications, occlusion and recanalization rate after 3 and 6A months. METHODS: Aneurysms in the right common carotid artery were created in 25 rabbits. The animals were divided into five groups of five animals each. The animals of group 1 (the control group) received no treatment of the induced aneurysms, the animals of groups 2 and 3 (killed at 3 and 6A months) were treated with standard GDC, and the animals of groups 4 and 5 (killed at 3 and 6A months) were treated with Matrix coils. RESULTS: Histopathological evaluation showed organized thrombus formation and connective tissue with neovascularization around the implanted coils in all the treated groups. The achieved occlusion rates in groups 2 and 3 were identical to those in groups 4 and 5. Thus the long-term results of aneurysm treatment with GDC and Matrix coils show no differences regarding occlusion and recanalization rates. The only noticeable difference was the difference in handling. More force was required to pushing the Matrix coils forward through the microcatheter and there was more friction in coil interaction in the aneurysm. CONCLUSION: The bioactive coating of the Matrix coil produces no significant benefit in achieving higher occlusion and lower recanalization rates, and the coil is more difficult to handle. Future bioactive coils must be shown to produce significantly better long-term results than GDC and their ease of handling has to be improved.     

Treatment of intracranial broad-neck aneurysms with a new self-expanding stent and coil embolization

BACKGROUND AND PURPOSE: Endovascular treatment of broad-neck intracranial aneurysms with detachable coils requires special techniques. Placement of a stent over the aneurysm neck and secondary coil embolization prevents coil migration and allows attenuated packing of the coils. However, access for the stent-delivery system can be technically limited in tortuous anatomy. We present six cases of broad-neck aneurysms treated with a new self-expanding stent and coil embolization. METHODS: Three aneurysms of the supraophthalmic internal carotid artery and three aneurysms of the basilar tip with extension to the origin of a posterior cerebral artery were treated. The stent was a new self-expanding stent with a 3F over-the-wire microcatheter delivery system. Coil embolization was performed with electrolytically detachable coils. Time-of-flight MR angiography was performed after treatment in five cases. Three other patients could not be treated with the stent because deployment was not possible after correct positioning of the delivery system. RESULTS: Access with the stent-delivery system was easy, and the aneurysm neck was covered sufficiently. After stent placement, total coil embolization was achieved in four and subtotal coil embolization was achieved in two. Parent arteries remained open, and no secondary coil migration was seen. On follow-up MR imaging, the stent was clearly visible and patency of the parent vessel and emerging branches was assessable. CONCLUSION: This new stent is a safe and efficient tool for the endovascular treatment of intracranial broad-neck aneurysms. Access to smaller vessels was easy, but the mechanism of deployment had to be improved. Follow-up MR imaging was sufficient.     

新型颅内支架Enterprise结合水解脱弹簧圈栓塞治疗颅内微小宽颈动脉瘤

目的总结应用新型颅内支架Enterprise结合水解脱弹簧圈栓塞治疗颅内微小宽颈动脉瘤的技术及疗效。方法6例颅内微小宽颈动脉瘤(直径<3mm,体/颈比<1.5)采用Enterprise支架结合水解脱弹簧圈栓塞,其中5例采用先放置支架覆盖动脉瘤颈再将微导管经支架网孔放入动脉瘤腔填塞弹簧圈进行栓塞,1例将微导管进入瘤腔后再释放支架进行弹簧圈栓塞。术后3～6个月进行临床随访。结果6例全部技术成功,支架均满意到位,载瘤动脉通畅,无手术并发症;动脉瘤完全闭塞4例,闭塞95%以上2例。术后患者均恢复良好,3～6个月临床随访无再出血及脑血栓形成。结论联合使用Enterprise支架和水解弹簧圈栓塞治疗颅内微小宽颈动脉瘤是一种安全有效的方法,但其长期疗效仍需进一步观察。     

血管内支架结合电解可脱弹簧圈治疗颅内动脉瘤

目的 初步总结使用血管内支架结合电解可脱卸弹簧圈（GDC）治疗颅内梭形及宽颈动脉瘤的体会,探讨其适应证、方法、疗效及并发症。方法 5例颅内梭形动脉瘤及12例宽颈动脉瘤,首先将冠脉支架跨动脉瘤颈放置,通过支架的网孔将微导管送入动脉瘤腔,继续填塞GDC。结果 13例动脉瘤致密填塞,3例大部分填塞,1例支架未能送入颅内而单用弹簧圈部分栓塞,载瘤动脉通畅,临床效果优良。结论 联合使用支架及微弹簧圈是治疗颅内梭形及宽颈动脉瘤的有效方法,远期疗效需进一步随访。     

Evaluation of Polyurethane Nasolacrimal Duct Stents: In Vivo Studies in New Zealand Rabbits

The purpose of this study was to evaluate the radiographic and biological effects of different polyurethane nasolacrimal duct stents in an animal model. Fifteen polyurethane nasolacrimal duct stents (n = 5 mushroom-type stents, n = 5 newly designed S-shaped TearLeader stents without hydrophilic coating, and n = 5 S-shaped TearLeader stents with hydrophilic coating) were implanted in the nasolacrimal ducts of eight unaffected New Zealand rabbits. One nasolacrimal system served as control. Clinical and radiographic follow-up was performed at 1-, 2-, and 4-week intervals, then after a 3-month interval, after which the animals were euthanized. All stents were implanted without major periprocedural complications. The stents proved to be patent by the end of the procedure. During follow-up, all mushroom-type stents were occluded at 4 weeks. None of these stents opened to forced irrigation. Clinically, all rabbits demonstrated severe dacryocystitis. Three out of five TearLeader stents without hydrophilic coating were blocked at 4 weeks; one out of five was open to irrigation. Best results were observed in the stent group with hydrophilic coating. Follow-up dacryocystography demonstrated patent stents in nasolacrimal ducts of all animals after 4 weeks. In only one of five cases, the coated stent became partially occluded after 2 months. These animals were free of clinical symptoms. After 3 months, at least three out of five stents still opened to forced irrigation and only one stent was completely blocked. Dislocation of the stents was not observed. Refinement of the stent surface and stent design improves the results of nasolacrimal duct stenting in this animal model. Implantation of hydrophilic-coated S-shaped stents is highly superior to conventional mushroom-type stents and noncoated stent types. Hydrophilic coating seems to prevent foreign-body reactions, resulting in maximized stent patency.     

Treatment of elastase-induced intracranial aneurysms in New Zealand white rabbits by use of a novel neurovascular embolization stent device

Introduction

This study aims to test a novel balloon expandable stent covered with a polytetrafluoroethylene membrane (neurovascular embolization cover (NEC), NFocus Neuromedical, Palo Alto, California) regarding angiographic and histologic aneurysm occlusion. Radiopacity, stent placement, navigation, flexibility, and intimal proliferation were also evaluated.

Methods

Eight aneurysms were induced in New Zealand white rabbits. Digital subtraction angiography (DSA) was performed directly after stent placement and after 5 and 10 min. Four and 8 weeks after stent placement, an intra-arterial DSA control was performed. The animals were then sacrificed and the aneurysms histologically evaluated.

Results

The radiopaque markers were clearly visible. Although all the stents were easily navigated into the subclavian artery, the limited flexibility of the stent resulted in straightening of the vessel in four cases. As a result, exact stent placement was achieved and acutely confirmed in only two cases. However, at sacrifice, angiographic and histologic occlusion was noted at follow-up in five aneurysms.

Conclusion

In tortuous anatomy, the relative stiffness of the stent makes exact stent placement challenging. This may have been exacerbated by the movement of the vessels due to proximity to the heart in this model. Future studies should evaluate whether existing residual flow into an aneurysm lumen might lead to embolization without any additional treatment. Anticoagulation remains a very important part of aneurysm treatment with stents. The trend toward aneurysm occlusion by excluding it from the blood circulation seems a promising method in future endovascular therapy. The NEC device shows good potential.     

Utility of CT angiography and MR angiography for the follow-up of experimental aneurysms treated with stents or Guglielmi detachable coils

BACKGROUND AND PURPOSE: Previous studies have depicted arterial and aneurysmal anatomy with three-dimensional time-of-flight (3D-TOF) MR angiography before and after treatment with Guglielmi detachable coils (GDCs) and with CT angiography before and after treatment with stents and stent-grafts. We investigated the ability of time-resolved contrast-enhanced 3D MR angiography (3D MR digital subtraction angiography [DSA]) to accurately depict the anatomy of experimental lateral aneurysms before and after treatment with GDCs and a variety of stents or stent-grafts, and compared these findings with 3D-TOF MR angiography without and with contrast enhancement and CT angiography. METHODS: Two nitinol stents, two nitinol-polytetrafluoroethylene (PTFE) stent-grafts, and two stainless steel stents were deployed in three dogs with experimental carotid aneurysms. In a fourth animal, one of three aneurysms was completely occluded with GDCs. The other two aneurysms were loosely packed to ensure persistence of some residual aneurysmal lumen. Cut-film angiography, CT angiography, 3D-TOF MR angiography without and with contrast enhancement, and 3D MR DSA were performed in all dogs before and 3 weeks after treatment. RESULTS: 3D MR DSA was superior to conventional 3D-TOF MR angiography without and with contrast enhancement in accurately depicting experimental lateral aneurysms and superior to CT angiography in depicting aneurysms treated by GDCs. 3D MR DSA and CT angiography were comparable in depicting vessels treated with nitinol stents and stent-grafts, whereas CT angiography was superior for showing vessels treated by stainless steel stents. CONCLUSION: We recommend further development and clinical evaluation of 3D MR DSA for imaging cerebral aneurysms before and after treatment with GDCs. 3D MR DSA or CT angiography may be useful for evaluating vessels containing nitinol stents or nitinol-PTFE stent-grafts, whereas CT angiography should be used for follow-up of vessels treated by stainless steel stents.