Long-term Results Of Endovascular Treatment Research Articles

Aortic treatment in connective tissue disease

Connective tissue disease (CTD) represents a group of genetic conditions characterized by disruptive matrix remodeling. When this process involves aortic and vascular wall, patients with CTD have a high risk of developing arterial aneurysms, dissections and ruptures. Open surgical repair is still the gold standard therapy for patients with CTD with reasonable morbidity and mortality risk. The surgical treatment of CTD often requires multiple operations. In the endovascular era, fenestrated and branched stent grafts may play a role in reducing the complications of multiple open operations. Although the long-term results of endovascular treatment in the setting of CTD are unknown, it is generally accepted that endovascular treatment is restricted to selected patients with high surgical risk. In an emergency setting, endovascular intervention can serve as a lifesaving bridge to elective open aortic repair. Aortic centers performing a large volume of complex open and endovascular aortic repairs have started to combine these two techniques in a staged fashion. The goal is to reduce the morbidity and mortality associated with extensive aortic repairs in CTD patients. For this reason, recommend endovascular therapy when a "graft-to-graft" approach is possible. In this scenario, the surgeon who performs the open repair must take into consideration future interventions. Surgical repair in any aortic segment should allow creation of proximal and distal landing zones over 4 cm to secure the sealing of a future stent graft. Connective tissue disease should be treated with a multidisciplinary approach, in high volume centers. Endovascular treatment represents a potential option in patients at high risk for open repair. Staged hybrid procedures have emerged as a way to reduce spinal cord ischemia and avoid multiple open surgeries. The aim of this article is to discuss the management of aortic diseases in CTD, focusing on to the role of standard open surgery and emerging endovascular treatment, and to give an overview of the few series published regarding this topic with a small number of patients.

Long-term results of endovascular treatment for May-Thurner syndrome.

Long-term results of endovascular treatment for May-Thurner syndrome.

Long-Term Results of Endovascular Treatment of Atherosclerotic Stenoses or Occlusions of the Coeliac and Superior Mesenteric Artery in Patients With Mesenteric Ischaemia

Over the past decade, primary percutaneous mesenteric artery stenting (PMAS) has become an alternative to open revascularisation for treatment of mesenteric ischaemia. Institutes have presented favourable short-term outcomes after PMAS, but there is a lack of data on long-term stent patency. One hundred and forty-one patients treated by PMAS for acute and chronic mesenteric ischaemia over an 8 year period were studied. Anatomical success was assessed by duplex ultrasound and/or CT angiography. A stenosis ≥70% was considered to be a failure. Eighty-six coeliac arteries (CA) and 99 superior mesenteric arteries (SMA) were treated with PMAS in 141 patients. Nine CAs (10%) and 30 SMAs (30%) were occluded at the time of treatment. Median follow-up was 32 months (IQR 20–46). The overall primary patency rate at 12 and 60 months was 77.0% and 45.0%. The overall primary assisted patency rate was 90.3% and 69.8%. Overall secondary patency was 98.3% and 93.6%. This study shows excellent long-term secondary patencies after PMAS, comparable with published data on long-term patencies after open surgical revascularisation.

Long-Term Results of Endovascular Treatment of Atherosclerotic Stenoses or Occlusions of the Coeliac and Superior Mesenteric Artery in Patients With Mesenteric Ischaemia

Over the past decade, primary percutaneous mesenteric artery stenting (PMAS) has become an alternative to open revascularisation for treatment of mesenteric ischaemia. Institutes have presented favourable short-term outcomes after PMAS, but there is a lack of data on long-term stent patency. One hundred and forty-one patients treated by PMAS for acute and chronic mesenteric ischaemia over an 8 year period were studied. Anatomical success was assessed by duplex ultrasound and/or CT angiography. A stenosis ≥70% was considered to be a failure. Eighty-six coeliac arteries (CA) and 99 superior mesenteric arteries (SMA) were treated with PMAS in 141 patients. Nine CAs (10%) and 30 SMAs (30%) were occluded at the time of treatment. Median follow-up was 32 months (IQR 20-46). The overall primary patency rate at 12 and 60 months was 77.0% and 45.0%. The overall primary assisted patency rate was 90.3% and 69.8%. Overall secondary patency was 98.3% and 93.6%. This study shows excellent long-term secondary patencies after PMAS, comparable with published data on long-term patencies after open surgical revascularisation.

ОЦЕНКА ЭФФЕКТИВНОСТИ РЕНТГЕНЭНДОВАСКУЛЯРНОГО ЛЕЧЕНИЯ БОЛЬНЫХ ОБЛИТЕРИРУЮЩИМ АТЕРОСКЛЕРОЗОМ АРТЕРИЙ НИЖНИХ КОНЕЧНОСТЕЙ С ПРОТЯЖЕННЫМИ ОККЛЮЗИЯМИ ПОВЕРХНОСТНОЙ БЕДРЕННОЙ АРТЕРИИ

The article presents 2-year results of endovascular treatment of 68 patients with peripheral arterial disease, chronical limb ischemia stage 2B-4 (by Fontain-Pokrovsky), with the vascular lesions of type D according to TASC II classification, which is characterized by long, over 20 cm occlusion of the superficial femoral artery, popliteal artery involvement and/or arteries of the lower leg. The rationale to perform endovascular recanalization and stenting of extended occluding lesions of the arteries infrainguinal segment in our study were the results of the analysis of the literature data on the treatment of patients with occlusions of the femoro-popliteal segment, namely the development of postoperative complications after femoral-popliteal bypass surgery, such as lymphorrhea, primary thrombosis of the bypass, bleeding, acute renal failure and infection complications; occlusion of femoro-popliteal bypass grafts at 2 years after surgery reaching 60%, the need to perform repeated operations in 45% of patients; prolonged postopera-tive rehabilitation and therefore low quality patients. Analyzing treatment results testified the effectiveness and safety of endovascular method. Technical success of recanalization, angioplasty and stenting of arteries was successfully performed in all patients. Restenosis occurred in 13 patients (15%) at 1 year. After 2 years restenosis was revealed in another 4 patients. Primary patency during the first year of follow-up was 74.7 per cent, for 2 years - 72%. Secondary patency after 2-year follow-up after performing balloon angioplasty in patients with restenosis segment was 100%. Fatal complication of retroperitoneal bleeding developed in 1 patient. The overall incidence of complications was 6%. Most patients were discharged after 3 days. We continue to accumulate clinical observation and study long-term results of endovascular treatment of patients with peripheral arterial disease, with the vascular lesions of type D according to TASC II classification.

TCTAP A-074 Hospital and Long-Term Results of Endovascular Treatment of Patients with Acute Myocardial Infarction Complicated with Primary Ventricular Fibrillation

TCTAP A-074 Hospital and Long-Term Results of Endovascular Treatment of Patients with Acute Myocardial Infarction Complicated with Primary Ventricular Fibrillation

Outcomes of the Endovascular Treatment for the Supra-Aortic Trunks Occlusive Disease: A 14-Year Monocentric Experience

Endovascular treatment of proximal supra-aortic trunks (SAT) has become a safe and reliable alternative to conventional open surgery, with a lower morbimortality rate and good short- and middle-term patency rates. The aim of our study was to assess the long-term results of endovascular treatment of proximal lesions of the SAT (brachiocephalic trunk, common carotid artery, and subclavian artery) and identify predictive risk factors of restenosis. From 1999 to 2013, 67 consecutive stenotic lesions of the proximal SAT were treated by angioplasty (13.4%) or stenting (86.6%) in 63 patients with a mean age of 65.5years (40-87). Procedures were performed under general (69%), local (24%), or locoregional (7%) anesthesia, with percutaneous puncture (47.8%) or open access (52.2%). Patients were followed up for 3, 6, and 12months, and then every year with clinical examination, Doppler ultrasound and if required an angio-CT scan. The technical success rate was 98.5%. There was no postoperative death or strokes. One myocardial infarction occurred at day 2. There were 2 access complications: a nonsurgical hematoma after brachial access and a brachial thrombosis postpuncture. The mean follow-up was 4.5years (2-163months). The primary- and assisted-patency rates were 90.1%, 86.4%, 77.9% and 93.3%, 91.4%, 82.9% at 1, 2, and 5 years, respectively. Eleven restenosis (16.4%) occurred at 28.5months (3, 0-112, 0) of follow-up. Four of them required an endovascular repair and 3 required a surgical one. The restenosis rate was 17.5% in the stented group on average at 30.2months of follow-up (range, 3.0-112.0) and 10% in the group of patients with angioplasty alone at 8 months of follow-up, without significant statistically difference (P=0.9). No predictive risk factor of restenosis was statistically identified. The endovascular treatment of proximal stenosis of SAT is a safe, reliable, and efficient technique with a low morbidity and mortality. The long-term results are good, but restenosis can occur. Long-term follow-up should be performed to detect and treat restenosis.

Excellent long-term results with iliac stenting in local anesthesia for post-thrombotic syndrome.

BackgroundOnly 20% of iliac veins will recanalize on anticoagulation (AC) treatment alone and may, therefore, develop venous obstruction after iliofemoral deep venous thrombosis (DVT). A considerable number of these patients will suffer from post-thrombotic syndrome (PTS) leading to impaired quality of life in more than 50%. Endovascular treatment for iliac vein obstruction using stents is known to alleviate PTS symptoms in selected patients.PurposeTo report the Danish long-term results of endovascular treatment with iliac stenting.Material and MethodsFrom 2000 to 2013 consecutive patients were evaluated and 19 patients with severe venous claudication were identified and subsequently underwent angioplasty and stenting. AC treatment was prescribed for 6 months, and knee-high class II compression stocking recommended for 1 year. Scheduled follow-up was done in the outpatient clinic at 6 weeks, 3 months, and annually thereafter.ResultsNineteen patients, all women, all with left-sided iliac vein obstruction, and all with severe PTS symptoms were included. The median follow-up time was 81 months (range, 1–146 months; mean, 69 months). Primary patency rate of the inserted iliac stent was 89% (17/19) and 16 patients (84 %) had almost or total symptom relief at follow-up.ConclusionEndovascular stenting of iliac obstruction in local anesthesia is minimally invasive and shows excellent long-term outcomes for patients suffering from PTS.

Large Pulmonary Arteriovenous Malformations: Long-Term Results of Embolization with AMPLATZER Vascular Plugs

PurposeTo analyze the long-term results of endovascular treatment of large pulmonary arteriovenous malformations (PAVMs) using the AMPLATZER vascular plug (AVP; AGA Medical Corp, Golden Valley, Minnesota). Materials and MethodsBetween May 2007 and April 2011, 18 patients with 24 large PAVMs, defined as PAVMs that had a feeding artery with a diameter of ≥ 8 mm, were treated with AVP I or AVP II. A single AVP device was used for each PAVM. Aneurysmal sac diameters, sac perfusion, sac shrinkage, and complete resolution before and after the intervention were analyzed. Complete histories, laboratory values, physical examinations, and multidetector computed tomography images were reviewed. The mean occlusion time for AVP I and AVP II and the mean arterial oxygen saturation (SaO2) before and after the intervention were compared. ResultsThe mean diameter of the feeding artery was 11.46 mm ± 2.18 (range, 8–13.3 mm). The mean occlusion time was 7.34 minutes ± 1.23 for AVP I and 6.25 minutes ± 1.12 for AVP II (P = .11). The mean SaO2 before and after the intervention was 63.71% ± 8.10% (range, 51%–76%) and 96.28% ± 0.49% (range, 96%–97%), respectively (P = .045). No major periprocedural complications were observed. The mean follow-up duration was 36.33 months ± 10.63 (range, 28–56 mo). During the follow-up period, there were no persistent sac perfusions, migration of the AVPs, major complications, or recanalizations. ConclusionsTreatment of large PAVMs with AVPs is an effective method for obtaining excellent long-term results. Embolization of large feeding arteries can be accomplished with AVPs without major complications.

Endovascular treatment of symptomatic high-grade vertebral artery stenosis

The purpose of this study was to evaluate the initial and long-term results of endovascular treatment (EVT) in patients with symptomatic high-grade extracranial vertebral artery (VA) origin stenosis. From February 2001 to March 2013, 73 consecutive patients (33 men with a mean age of 61.7± 8.8years) underwent EVT for symptomatic high-grade VA stenosis. Preoperative evaluation included Duplex ultrasonography and arteriography. After successful treatment, all patients were followed up at 1, 3, 6, and 12months after the procedure and every 6months thereafter. Successful EVT of the VA stenosis was achieved in 68 patients (93.2%). All procedures were performed without use of cerebral protection. The early complication rate was 5.5%, which included one periprocedural transient ischemic attack, two hematomas at the puncture site, and one allergic reaction to the contrast agent. No in-hospital deaths occurred. During follow-up (mean, 44.3± 31.2months; range, 2-144months), the primary patency rates at 1, 3, 5, and 7years were 98.4%, 87.3%, 87.3%, and 87.3%, respectively. Ultrasound Doppler controls during follow-up detected seven VA restenoses (10.3%). Univariate analysis failed to identify any variable predictive of long-term patency of successfully treated VA stenosis. EVT of symptomatic VA origin stenosis is a safe and effective procedure associated with low risk and good long-term results, even without use of cerebral protection devices.

ENDOVASCULAR TREATMENT OF ISCHEMIC HEART DISEASE IN PATIENTS WITH MULTIVESSEL CORONARY ARTERY DISEASE: IMMEDIATE AND LONG-TERM RESULTS

Immediate and long-term results of endovascular treatment of multivessel coronary artery disease by using different revascularization strategies were analyzed in 171 patients. Duration of follow up ranged from 12 to 18 months. Complete myocardium revascularization was performed in 63 patients, culprit vessel revascularization--in 86 pts and incomplete revascularization--in 22 pts. Results of this study showed that strategy of complete and culprit vessel revascularization in patients with multivessel coronary artery disease has comparable immediate and long-term results. Strategy of incomplete revascularization reduce immediate clinical success and lead to increased number of myocardial infarctions and needs of coronary artery bypass surgery in long-term follow-up period.

Long-Term Follow-Up of Endovascular Treatment for Trans-Atlantic Inter-Society Consensus II Type B Iliac Lesions in Patients Aged

To study the initial and long-term results of endovascular treatment in patients aged <50 years with trans-Atlantic inter-society consensus-II type B unilateral iliac lesions and chronic limb ischemia. From January 2000 to February 2010, 60 consecutive endovascular interventions were performed on 23 women and 37 men aged ≤50 years. After successful treatment, all patients were followed up at 1, 3, 6, and 12 months after the procedure and every 6 months thereafter. Successful percutaneous revascularization of the iliac artery was achieved in 56 patients (93.3%). The early vascular-related complication rate was 6.7%. The primary patency rates at 1, 3, and 5 years were 88%, 59%, and 49%, respectively. Cox univariate analysis revealed that an age range of 45 to 50 years (hazard ratio [HR]: 0.290; 95% confidence interval [CI]: 0.152-0.553; P = 0.0001), lower preprocedural ankle-brachial index (HR: 2.438; 95% CI: 1.04-5.715; P = 0.047), lesion length >5 cm (HR: 0.838; 95% CI: 0.746-0.943; P = 0.003), and diabetes (HR: 2.005; 95% CI: 1.010-3.980; P = 0.047) had significant influence on decreasing primary patency. Endovascular treatment of TASC-II type B iliac lesions in patients aged <50 years is a safe procedure with low procedural risk. Primary patency rates at 1, 3, and 5 years were 88%, 59%, and 49%, respectively.

Mid- and Long-Term Results of Endovascular Treatment in Thoracic Aorta Blunt Trauma

Study Aim. Evaluation of results in blunt injury of the thoracic aorta (BAI) endovascular treatment. Materials and Methods. Sixteen patients were treated for BAI. Thirteen patients had associated polytrauma, 4 of these had a serious hypotensive status and 4 had an hemothorax. In the remaining 3, two had a post-traumatic false aneurysm of the isthmus and 1 had a segmental dissection. In those 13 patients a periaortic hematoma was associated to hemothorax in 4. All patients were submitted to an endovascular treatment, in two cases the subclavian artery ostium was intentionally covered. Results. One patient died for disseminated intravascular coagulation. No paraplegia was recorded. No ischemic complications were observed. A type I endoleak was treated by an adjunctive cuff. During the followup (1–9 years) 3 patients were lost. A good patency and no endoleaks were observed in all cases. One infolding and 1 migration of the endografts were corrected by an adjunctive cuff. Conclusion. The medium and long term results of the endovascular treatment of BAI are encouraging with a low incidence rate of mortality and complications. More suitable endo-suite and endografts could be a crucial point for the further improvement of these results.

Early and long-term comparison of endovascular treatment of iliac artery occlusions and stenosis

This study evaluated early and long-term results of endovascular treatment of iliac artery occlusions and compared these outcomes with those in patients treated for stenotic lesions. During a 10-year period ending in January 2010, 223 endovascular procedures to treat aortoiliac occlusive disease (PAD) were performed. All patients were prospectively enrolled in a dedicated database. The intervention was performed for iliac occlusion in 109 patients (group 1) and for iliac stenosis in 114 (group 2). Early results were analyzed and compared by χ² and Fisher exact tests. Follow-up consisted of clinical examination and duplex scanning at discharge, ≤ 3 months, at 6 and 12 months, and yearly thereafter. Follow-up results were analyzed with Kaplan-Meier curves and compared with the log-rank test. The two groups had similar risk factors for atherosclerosis and comorbidities. Critical limb ischemia was more common in group 1 (20.5%) than in group 2 (8.5%; P = .01). Intraoperative technical details were similar, except for a higher percentage of brachial and contralateral femoral access and more frequent use of nitinol stents in group 1. Two immediate technical failures occurred, one in both groups, requiring immediate conversion to surgical bypass. Four intraoperative iliac ruptures occurred, two in each group; all were successfully treated with covered stents. An additional 10 immediate complications occurred (8 in group 1; 2 in group 2), one of which required conversion to open surgical bypass. The cumulative rate of perioperative complications was 9% in group 1 and 3.5% in group 2 (P = .08). Primary patency at 30 days was 97.3% and 98.7%, respectively. Mean duration of follow-up was 28.4 months; 203 patients (91%) had a regular postoperative follow-up visit. At 60 months, primary patency in group 1 vs group 2 was 82.4% vs 77.7% (P = .9), assisted primary patency was 90.6% vs 85.5% (P = .4), and estimated secondary patency was 93.1% vs 92.8% (P = .3). The cumulative rate of reintervention during follow-up (excluding reinterventions performed in the perioperative period) was 2.5% in group 1 and 12.5% in group 2 at 60 months (P = .09). Univariate analysis in group 1 failed to find any of the examined risk factors significantly affected long-term primary patency rates. In our experience, endovascular treatment of iliac occlusions provides excellent early and long-term results, similar to those obtained in the treatment of stenotic lesions.

SS9. Long-term Results of Endovascular Treatment of Subclavian and Innominate Arterial Stenosis

SS9. Long-term Results of Endovascular Treatment of Subclavian and Innominate Arterial Stenosis

Treatment of traumatic rupture of the thoracic aorta

Interest for traumatic thoracic aorta rupture stems from the fact that its number continually increases, and it can be rapidly lethal. The aim of this study is to present early and long term results as well as experiences of our team in surgical treatment of traumatic thoracic aorta rupture. Our retrospective study includes 12 patients with traumatic thoracic aorta rupture treated between 1985 and 2007.There were 10 male and two female patients of average age 30.75 years (18-74). In six cases, primary diagnosis was established during the first seven days days after trauma, while in 6 more than one month later. In 11 cases, classical open surgical procedure was performed, while endovascular treatment was used in one patient. Three (25%) patients died, while two (16.6%) had paraplegia. Nine patinets (75%) were trated without complications, and are in good condition after a mean follow-up period of 9.7 years (from one month to 22 years). Surgical treatment requires spinal cord protection to prevent paraplegia, using cardiopulmonary by-pass (three of our cases) or external heparin-bonded shunts (five of our cases). Cardiopulmonary by-pass is followed with lower incidence of paraplegia, however it is not such a good solution for patients with polytrauma because of haemorrhage. The endovascular repair is a safe and feasible procedure in the acute phase, especilly because of traumatic shock and polytrauma which contributes to higher mortality rate after open surgery. On the other hand, in chronic postrauamatic aortic rupture, open surgical treatment is connected with a lower mortality rate and good long-term results. There have been no published data about long-term results of endovascular treatment in the chronic phase.

Five-year report of a multicenter controlled clinical trial of open versus endovascular treatment of abdominal aortic aneurysms

Compare long-term results of endovascular treatment and standard open repair of abdominal aortic aneurysms in a multicenter, concurrent-controlled trial. 334 subjects were treated with standard open repair (control, n = 99) or the original EXCLUDER Bifurcated Endoprosthesis (test, n = 235). Five-year clinical evaluations and corelab radiographic results are analyzed. Overall and aneurysm-related survival are similar. There have been ten open conversions, most frequently for enlarging sacs without endoleak. Two patients died after conversion. Including reinterventions and complications of reinterventions as adverse events, there is significant, persistent long-term reduction in major adverse events. At 5 years, corelab reported 0% limb narrowing, 0% trunk migration, 0% component (contralateral leg, aortic extender, and iliac extender) migration, 0% fracture, endoleak in 3% (2 type II/68), and aneurysm growth (>5 mm compared to baseline) in 38% (30/78) of the test group. There are no aneurysm ruptures in either test or control group. After 5 years follow-up, endovascular repair is a safer and effective treatment compared with open surgical repair for abdominal aortic aneurysms. Major adverse events are less frequent with the endograft despite the need for late reinterventions. Aneurysm expansion is observed in nearly two-fifths of patients but is not associated with endoleak or aneurysm rupture. Multicenter clinical trials are evaluating a newer version of this device designed to avoid this high rate of sac expansion.

Long-term results of endovascular treatment of acute thoracic aortic lesions

Objective: To determine the efficacy and the long-term results of endovascular treatment of traumatic aortic rupture, aortobronchial fistula and penetrating aortic ulcer

Endovascular Treatment with Platinum Coils

Recanalization after coil occlusion is a concern for long-term results of endovascular treatment. Knowledge of molecular events following coil occlusion and recanalization could help design specific strategies to promote permanent occlusion. Platinum coils were implanted into canine maxillary, vertebral or lingual arteries. Coil occlusion (treatment 1), routinely followed by recanalization was compared with two strategies to prevent recanalization: beta radiation using (32)P coils (treatment 2) and endothelial denudation, using an endovascular device, followed by coil occlusion (treatment 3). The evolution of initial complete occlusions was followed by angiography and pathology at three months. Levels of messenger RNA of vWF (von Willebrand factor), SMA (smooth muscle actin), CD14, CD31 (or PECAM-1: Platelet Endothelial Cell Adhesion Molecule-1), PDGFBB (platelet-derived growth factor), TGF-b1 (transforming growth factor), MCP-1 (macrophage chemoattractant protein), Angiopoietins, Metalloproteinases-9, 14 and inhibitors (TIMP- 2, 4) were followed by Reverse Transcription and Polymerase Chain Reaction (RT-PCR). Analyses were performed one, four, seven and 14 days after coiling, and levels of expression after the three treatments were compared using ANOVAs. Intact arteries treated with platinum coils routinely recanalize (100%), but arteries treated by denudation and coiling or with radioactive coils recanalize in only 17% and 4% respectively (P<.001). Recanalization was associated with increased levels of vWF mRNA at seven days, a finding that was not observed with denudation or radiation (P=.015). There was no other significant difference. Recanalization is associated with early vWF expression, perhaps reflecting the development of endothelialized channels through thrombus formed after coil occlusion.

New Devices Designed to Improve the Long-Term Results of Endovascular Treatment of Intracranial Aneurysms

Endovascular coiling can improve the outcome of patients with ruptured intracranial aneurysms, but angiographic recurrences are frequent compared to surgical clipping. New coils or devices have been introduced to improve long-term results of endovascular treatment but none have been the object of a valid clinical trial. We have proposed a multicentric randomized double-blind study comparing radioactive and standard coil occlusion of aneurysms. The purpose of this article is to review issues that are specific to the design of clinical trials to assess embolic agents that could improve the long-term efficacy of endovascular treatment of intracranial aneurysms. The proposed trial is a randomized, multi-center, prospective, controlled trial comparing the new generation coils to standard platinum coils. Blinding, if at all possible, is preferable to minimize bias, at least for follow-up angiographic studies that should cover a period of 18 months. All patients with an intracranial aneurysm eligible for endovascular treatment would be proposed to participate. The study would enrol approximately 500 patients equally divided between the two groups, recruited within two years, to demonstrate a decrease in the recurrence rate, the primary outcome measure, from 20% to 10%. Secondary outcome measures should assure that complications, initial clinical and angiographic results remain unchanged. Independent data safety and monitoring committees are crucial to the credibility of trials and to ensure scientific rigor and objectivity. The scientific demonstration of an improved long-term efficacy, without significant compromise regarding safety, is mandatory before considering the widespread use of a new embolic device for the endovascular treatment of aneurysms.