Balloon Remodeling Research Articles

An Analysis of Inflation Times During Balloon-Assisted Aneurysm Coil Embolization and Ischemic Complications

The introduction of balloon remodeling has revolutionized the approach to coiling of wide-neck aneurysms. We studied the effects of balloon inflation during coil embolization on ischemic complications. A retrospective review was undertaken of the most recent 147 patients undergoing balloon remodeling for unruptured intracranial aneurysm coil embolization at a single institution (81 balloon, 66 unassisted). All underwent postprocedural MRI. Among patients in the "balloon" group, the mean total inflation time was 18 minutes (range, 1-43), a mean number of inflations of 4 (range, 1-9), a mean maximum single inflation time of 7 minutes (range, 1-19), a mean reperfusion time of 2.2 minutes between inflations, and an average procedure time of 2 hours and 10 minutes. Asymptomatic diffusion-weighted imaging abnormalities were detected on postprocedural MRI in 21.5% of patients and symptomatic lesions were identified in 3.8%. Both silent and symptomatic ischemic rates were similar in the internal control group. Patients with ischemic findings were older and more likely have diabetes; no differences were found with respect to total balloon inflation time, number of inflations, maximum inflation time, or reperfusion times. We found no significant relationship between balloon inflation practices and ischemic events. Older and diabetic patients were more likely to have ischemic events develop.

Letter by Pierot Regarding Article “Flow-Diverter Stent for the Endovascular Treatment of Intracranial Aneurysms: A Prospective Study in 29 Patients With 34 Aneurysms”

To the Editor: We read with great interest the results of a prospective study regarding the use of a flow-diverter stent for endovascular treatment of intracranial aneurysms.1 Twenty-nine patients with 34 complex aneurysms were treated. Treatment failed in 3 patients (10.3%). As in previous series, the rate of perioperative clinical complications was low, but because of delayed complications, the mortality and morbidity rates were 4% and 15%, respectively. This series described the initial experience of 3 centers with a completely new device during the ascending phase of the learning curve. Therefore, it is probably not appropriate to make definitive conclusions with such a limited and preliminary experience. Flow diversion is a new endovascular approach dedicated to the treatment of complex aneurysm types: large and giant, fusiform, and wide-neck aneurysms. For some of these lesions, no alternative treatment is available. Surprisingly, in the Lubicz et al1 series, the number of small aneurysms treated with flow diverters is quite high (aneurysms with diameters <10 mm: 18/34 patients …

Endovaskuläre Therapieoptionen der aneurysmatischen Subarachnoidalblutung

Aneurysmal subarachnoid hemorrhaging (ASH) is a severe condition with an acute symptomatic, often with a difficult course and accompanied by many complications. Aneurysms can be detected using computed tomography (CT), magnetic resonance angiography (MRA) and digital subtraction angiography (DSA). Possible therapy options for ASH are surgical clipping and endovascular treatment using platinum coils. The surgical approach is an effective and safe method for avoiding recurrent bleeding.So-called Guglielmi detachable coils, with which aneurysms can be successfully embolized, have been available since 1991. Initially only a few different sizes of platinum coils were available but now complex forms of platinum coils with different lengths and rigidness are available so that many forms of aneurysm can be treated. Broad-based aneurysms, which could previously only be treated by surgery, can now be treated by the so-called balloon remodeling technique or stent-assisted coiling, whereby a balloon or stent is placed in the parent vessel to act as a scaffold for the coil. The results of the ISAT study demonstrated that a better outcome for patients could be achieved by endovascular treatment of aneurysms than by neurosurgical clipping of ruptured aneurysms. For this reason the first option should be endovascular treatment when possible. Asymptomatic aneurysms are being observed increasingly more often and primary treatment should be endovascular when possible. The somewhat higher re-bleeding rate for endovascular treatment could not diminish the better results of the ISAT study even during the 5-year follow-up.

Thromboembolic events associated with endovascular treatment of cerebral aneurysms

ObjectiveTo evaluate the rate of peri-procedural thromboembolic events after the endovascular treatment of cerebral aneurysms. The rate of diffusion-positive lesions was assessed in relation to selected procedural and technical factors.Methods184...

Endovascular therapy for selected (most non-surgical) intracranial aneurysms in a Brazilian University Hospital

The objective of this study was to evaluate technical, clinical and angiographic results of a nonsurgical series of intracranial aneurysms treated by endovascular approach at Hospital das Clínicas of Medical School of Ribeirão Preto - University of São Paulo. Between August 2005 and November 2008, 137 aneurysms in 106 patients were endovascularly treated. Of these, 101 were unruptured in 75 patients and 36 aneurysms in 31 patients were treated during the acute phase. The data were prospectively studied. Sixty three aneurysms (46%) were treated with coils alone, 52 (38%) with balloon remodeling, 15 (10.9%) with stent remodeling, and 7 (5.1%) with therapeutic occlusion of the internal carotid artery. Six clinical complications (5.7%) were related to the procedures, 3 (2.8%) transitory and 3 (2.8%) permanent. Angiographic follow-up was available for 97 aneurysms (70.8%), clinical monitoring for 77 patients (72.6%) and telephone contact for 97 (91.5%). The technical, clinical and angiographic results found in this study are similar to those reported in the literature.

Subarachnoid Contrast Enhancement After Endovascular Packing of Ruptured Intracranial Aneurysm Mimicking Procedure-related Intracerebral Hemorrhage: Case Report and Literature Review

Background Intraprocedural aneurysm rupture during embolization is a rare but life-threatening event, may be taken to reduce and improve the outcome of this tragic occurrence. We report an unusual case of endovascular packing of ruptured aneurysm with balloon assistance, followed by subarachnoid contrast enhancement (SCE) on computed tomography (CT) imaging immediately after the procedure, mimicking procedure-related intracerebral hemorrhage, the management however, differed from the patient with procedure-related hemorrhage. Methods Coil embolization of a ruptured aneurysm was carried out using the balloon remodeling technique with total occlusion of the aneurysm sac. During the procedure, there was no excursion of the microcatheter, coil mass, or microwire beyond the confines of the vascular compartment that would imply perforation. However, immediate postprocedural CT showed marked asymmetric enhancement that resembled procedure-related subarachnoid hemorrhage. This case showed that although a rare occurrence, temporary disruption of the blood-brain barrier can mimic procedure-related intracerebral hemorrhage. Agents (nimodipine and heparin) that prevent cerebral vasospasm and subsequent infarcts were continued regardless of appearance of SCE. Discussion We discuss the potential mechanisms of this phenomenon and review the literature on SCE after endovascular packing of ruptured aneurysm with balloon assistance, to raise the awareness of this event, so that appropriate measures must be taken to prevent procedure-related complication.

P-021 Endovascular treatment of wide necked intracranial aneurysms using microcatheter protective technique: techniques and outcomes in 71 aneurysms

IntroductionCatheter protective technique, an adjunctive technique of multiple microcatheter techniques, means positioning an additional microcatheter, instead of a balloon or stent, in the parent or side branching arteries to protect...

Intraaneurysmal balloon assistance for navigation across a wide-necked aneurysm

Endovascular obliteration of wide-necked aneurysms may be precluded by the inability to navigate across the aneurysm neck. The authors present a technique in which a Hyperform balloon is inflated within the aneurysm and used as a contact surface to "bounce" the remodeling balloon across the aneurysm neck. They have successfully used this technique in 3 patients to efficiently overcome vessel tortuosity, aneurysmal dead space, and balloon prolapse, allowing for obliteration of large, wide-necked aneurysms.

HyperForm balloon remodeling in the endovascular treatment of anterior cerebral, middle cerebral, and anterior communicating artery aneurysms: clinical and angiographic follow-up results in 800 consecutive patients

The purpose of this paper was to present the safety, efficacy, and clinical/angiographic follow-up results of HyperForm balloon-assisted endosaccular coil occlusion of distal anterior circulation bifurcation aneurysms. Over a 7-year period, the authors treated 864 middle cerebral artery, distal anterior cerebral artery bifurcation, and anterior communicating artery aneurysms by means of coil embolization with HyperForm balloon assistance in 800 patients. In 37 aneurysms, 2 HyperForm balloons were used simultaneously for remodeling. The overall mortality rate was 7.1%, including 1.4% procedural mortality. Various neurological deficits were present at discharge in 8.9% of the patients, and 4.4% had permanent disabling morbidity 6 months posttreatment (modified Rankin Scale score ≥ 2). Thromboembolic complications developed during the treatment of 15 aneurysms (1.7%) causing morbidity or mortality in 10 cases (1.3%). There were 14 intraoperative perforations (1.6%). In all 14 cases, the HyperForm balloon saved patients from severe bleeding. The perforation led to morbidity or mortality in 3 cases (0.4%); there were no negative consequences in 11. There were 726 patients with 757 aneurysms (87.6%) available for follow-up. Control angiograms were obtained at 6 months in 386 patients, at 1 year in 267, and at 2 years in 104, revealing an 82% complete obliteration rate according to the most recent follow-up angiograms. The satisfactory results obtained in this experience demonstrate that HyperForm balloon remodeling provides strong benefits for the endovascular management of middle cerebral, anterior cerebral, and anterior communicating artery aneurysms without increasing the risk of treatment. Not only does this technique allow for the safe treatment of these aneurysms, but it also expands the indications of endovascular treatment to include aneurysms that otherwise cannot be treated with simple coil embolization.

Endovascular treatment of ruptured and unruptured intracranial very small aneurysms

To evaluate the feasibility and safety of endovascular treatment of ruptured and unruptured intracranial very small aneurysms (< or = 3 mm in maximal diameter). Forty-eight intracranial very small aneurysms in 44 patients treated with endovascular therapy from June 2001 to August 2009 were reviewed retrospectively in clinical, imaging, interventional and follow-up data. Among 44 patients, there were 20 males and 24 females with a mean age of 57.8 years old. The Hunt-Kosnik grade was as follows: Grade 0 (n = 11); Grades I & II (n = 23); Grades III & IV (n = 9); and ungraded (n = 1). The sizes of 48 aneurysms were not more than 3 mm in maximal diameter. The locations of aneurysms were as follows: ACoA (n = 11), MCA (n = 8), PCoA (n = 14), ICA (n = 12), pericallosal artery (n = 1), VA (n = 1) and PICA (n = 1). Thirty-nine aneurysms were embolized with coil, of which 13 with stent assistance and 6 by balloon remodeling technique. The other 9 aneurysms underwent sole stent placement in parent artery. Among 39 coiling aneurysms, 100% occlusion was achieved in 9 aneurysms, 90% in 20, 80% in 9 and less than 80% in 1 respectively. Only one aneurysm ruptured during coiling. Two patients had transient hemiparesis and one patient had ataxia caused by bilateral cerebellar infarction postoperatively. All patients were clinically followed up for 4-90 months and no recurrent hemorrhage occurred. Thirteen patients received repeat angiography at 4-72 months post-treatment. And no radiological re-growth was detected. Endovascular treatment of ruptured and unruptured intracranial very small aneurysms seems to be technically feasible, relatively safe and practically effective.

Clinical and angiographic long-term follow-up of completely coiled intracranial aneurysms using endovascular technique

The anatomical evolution and clinical outcome of completely coiled intracranial aneurysms after endovascular embolization have rarely been studied separately. From their prospective database, the authors reviewed follow-up angiography and clinical outcome of 87 patients whose aneurysms were designated as 100% obliterated on immediate postembolization angiography. Ninety-one aneurysms (56 ruptured and 35 unruptured) in 87 patients were included in this study. Clinical outcome was evaluated using the Glasgow Outcome Scale. Follow-up angiographic findings were assessed and categorized as 1 of the following: no recanalization, recanalization with a neck remnant, or recanalization with a body remnant. For statistical analysis, the recanalization rate was correlated with: clinical presentation; the largest aneurysm diameter, aneurysm neck size, and dome-to-neck ratio; aneurysm location; and use of special techniques such as usage of a surface modified coil, balloon remodeling technique, or stent. At the latest clinical evaluation (mean 34.3 months), 81 (93.1%) of the 87 patients (91 aneurysms) had good clinical outcomes (Glasgow Outcome Scale Score 5). The procedure-related morbidity rate (permanent neurological deficit) was 2.3% (2 of 87), and there were no procedure-related deaths. On the latest follow-up angiography (mean 26.4 months), the recanalization rate was 26.4% (24 of 91 aneurysms): 16 (17.6%) with neck remnants and 8 (8.8%) with body remnants. The neck size of the recanalized aneurysms was statistically significantly larger than that of the nonrecanalized aneurysms (p = 0.006), and aneurysms with wide necks (> or = 4 mm) had a higher recanalization rate than those with a narrow neck (< 4 mm) (p = 0.002). There was no bleeding after endovascular treatment during the follow-up period. Completely coiled aneurysms after endovascular embolization demonstrated good clinical outcome, and there was no bleeding episode after endovascular treatment; however, there was a relatively high recanalization rate.

Management of a traumatic hepatic artery pseudoaneurysm and arterioportal fistula with a combination of a stent graft and coil embolization using flow control with balloon remodeling

We describe a child who presented with a traumatic hepatic artery pseudoaneurysm and arterioportal fistula, which were subsequently managed with an endovascular stent graft and coil embolization using flow control with balloon remodeling. This case demonstrates a rarely seen condition in the pediatric population and a novel management strategy, which should be considered in the management of this complex injury.

Endovascular Treatment of 174 Middle Cerebral Artery Aneurysms: Clinical Outcome and Radiologic Results at Long-term Follow-up

To retrospectively evaluate the immediate safety and efficacy as well as the clinical outcome and long-term angiographic results of endovascular treatment (EVT) of middle cerebral artery (MCA) aneurysms. This is a retrospective review of patients in whom coiling of MCA aneurysms was attempted over a 7-year period. Institutional review board approval and informed written consent were obtained. This study included 153 patients (90 women, 63 men; mean age, 49.5 years +/- 11.7 [standard deviation]) with 174 MCA aneurysms (71 unruptured, 103 ruptured). Complications of EVT, clinical outcome, and the results of either cerebral digital subtraction angiography (DSA) or magnetic resonance (MR) angiography were analyzed at initial, intermediate (6-18 months), and late (2-7 years) follow-up. Coiling was performed in 160 (92%) aneurysms in 141 patients. Periprocedural complications were observed in 31 (19.4%) procedures, including aneurysm perforations (n = 7, 4.4%) and thromboembolic events (n = 24, 15.0%). EVT induced permanent morbidity in eight (5.7%) patients, with severe neurologic impairment in three (2.1%) and two deaths (1.4%). Of 114 MCA aneurysms controlled by using DSA (n = 50) or MR angiography (n = 64) at 50 months +/- 14, 73 (64%) remained completely occluded, 31 (27.2%) recurred, and 12 (10.5%) major recurrences were retreated. A balloon remodeling technique allowed treatment of complex aneurysms (n = 63) but was associated with more recurrences in the long term (42.6%) than aneurysms treated without balloon assistance (16.4%; P = .016). EVT of MCA aneurysms was safe and long-term monitoring of patients showed a low rate of recurrence requiring retreatment. However, complex anatomy and long-term recurrences have to be addressed when considering EVT for MCA aneurysms.

024 Balloon remodeling technique in the treatment of wide necked aneurysms: intermediate and long term experience with identification of predictors for successful aneurysm occlusion

Objective: To present the results of retrospective analyses of aneurysms treated with the remodeling technique, and identify predictors for successful aneurysm occlusion on initial treatment and intermediate to long term...

Endovascular therapy of posterior circulation aneurysms

Objective To investigate the safety and feasibility of endovascular therapy in posterior circulation aneurysms. Method There were 47 patients with posterior circulation aneurysms in this group, 25 aneurysms located in the apex of basilar artery,4 aneurysms in superior cerebellar artery,5 aneurysms in posterior inferior cerebellar artery,2 aneurysms in anterior inferior cerebellar artery,9 dissect aneurysms in vertebral artery,other 2 patients suffered from multiple aneurysms. 23 patients were treated with coiling, 16 patients with balloon assisted coiling, 7 patients with Neuroform stent assisted coiling, 1 patient was with Neuroform stent. Results 37 patients received complete occlusion,9 patients received 95% occlusion. 1 patient combined with Moyamoya disease died of widespread brain swelling and cerebral hernia after the procedure. There was no SAH within follow-up period. DSA was performed in 5 patients, there was no recurrence. The patient solo-treated with stent was followed up with DSA one month later,and the aneurysm disappeared. Conclusions Endovascular therapy is a valuable and safe method for treatment of posterior circulation aneurysms, balloon remodeling and stent assistant embolization should be performed in wide-necked aneurysms. Key words: Intracranial aneurysm; Posterior circulation; Endovascular therapy

Fenestrated vertebrobasilar junction aneurysm: diagnostic and therapeutic considerations

Vertebrobasilar junction (VBJ) aneurysms are uncommon and are often found in association with basilar artery (BA) fenestration. The complex anatomical environment of the VBJ, and the complicated geometry of the fenestration make clipping of these aneurysms difficult. Therefore, endovascular treatment of these aneurysms is now widely accepted. The authors describe the case of a 43-year-old woman with sickle cell anemia. She presented with subarachnoid hemorrhage. Digital subtraction angiography was performed and depicted multiple intracranial aneurysms. The patient had a left superior hypophysial artery aneurysm, a right superior cerebellar artery-posterior cerebral artery aneurysm, and a VBJ aneurysm associated with a fenestration of the BA. The VBJ aneurysm was not identified on the initial angiogram and was only revealed after 3D rotational angiography was performed. The 3D reconstruction was critical to the understanding of the complex geometry associated with the fenestrated BA. The VBJ was reconstructed using a combination endovascular technique. The dominant limb of the fenestration was stented and balloon-assisted coiling was performed, followed by sacrifice of the nondominant vertebral artery using coils and the embolic agent Onyx. Postoperative angiography demonstrated successful occlusion of the aneurysm with reconstruction of the VBJ. To the authors' knowledge, this is the first report of a fenestrated VBJ aneurysm treated with the combination of stenting, balloon remodeling, coiling, and vessel sacrifice. Three-dimensional angiography was critical in making the correct diagnosis of the source of the subarachnoid hemorrhage and with operative planning.

DELAYED SYMPTOMATIC COIL MIGRATION AFTER INITIALLY SUCCESSFUL BALLOON-ASSISTED ANEURYSM COILING

To describe delayed migration of a coil loop after adjunctive balloon remodeling of an anterior communicating artery aneurysm. A 56-year-old man with a subarachnoid hemorrhage from a small anterior communicating artery aneurysm underwent successful coil embolization with adjunctive balloon remodeling. Eight days after the procedure, the patient returned with the acute onset of right lower extremity paralysis. Magnetic resonance imaging demonstrated an acute left anterior cerebral artery territory infarction. Angiography demonstrated that this infarct was secondary to the delayed migration of a coil loop out of the aneurysm and into the left A1 to A2 junction. Delayed migration of a coil loop after adjunctive balloon remodeling represents a rare but potentially severe complication of this technique.

“Waffle Cone” Technique for Intra/Extra-Aneurysmal Stent Placement for the Treatment of Complex and Wide-Necked Bifurcation Aneurysm

Endovascular treatment of intracranial aneurysms by coiling has become an accepted alternative to surgical clipping (1). In cases of wide-necked and sidewall aneurysms, selective embolization is difficult because of the risk of coil protrusion into the parent vessel. The use of three-dimensional coils, stents (2), and balloon remodeling have all aided the attempt to adequately manage such lesions. However, compared with sidewall aneurysms, bifurcation aneurysms are more challenging from an endovascular standpoint. Because of their specific anatomy and hemodynamics, the tendency to recur and rerupture is higher. Several authors have reported successful treatment of these complex and wide-necked bifurcation aneurysms by using Yconfigured dual stent-assisted coil embolization (3,4), the double microcatheter technique (5), a more compliant balloon remodeling technique (6), the TriSpan neck-bridge device (7), or the waffle cone technique (8).We describe two cases of widenecked bifurcation aneurysms in which the waffle cone technique was used for coil embolization. The waffle cone technique was first described in 2006; however, the small number of published cases and the lack of follow-up prevent one from assessing this technique's durability and the probability of recanalization.We report the cases of two patients harboring unruptured wide-necked bifurcation aneurysms that were treated and followed-up for six months.

Stents for Intracranial Aneurysms: Indications, Limits and Non Indications

There are quite a few treatment options for embolization of broad based aneurysms. Besides a huge assortment of specifically 3D configured coils to treat those still challenging aneurysms Prof. Moret introduced a reconstruction technique using temporary inflation of a non-detachable balloon in front of the aneurysm neck during each coil placement. Although this method probably enables treatment of a wide range of wide necked aneurysms, some disadvantages have to be taken into account. The risk of coil migration after deflation of the balloon could still be a problem and more often, expansion of the coil package after balloon deflation is observed and might narrow the parent artery. This is clearly important if the parent artery has a small diameter. In such cases slight overinflation of the ballon is not always adequate and damage to the vessel wall is conceivable. Using this method the risk of intraprocedural aneurysm rupture especially in small aneurysms might be a real problem because intraaneurysmal pressure can rise dramatically. Damage of the already dysplastic, aneurysm bearing arterial segment due to balloon inflation is also reported. This can lead to sacrification of the vessel necessitating permanent occlusion. Although it is postulated that with balloon protection volume density of inserted coils can be increased the remaining question is still: is there any reduction of recanalisation in really broad based aneurysms treated with the remodelling technique? So far, no data are available to prove this hypothesis. With the introduction of self-expanding stent-systems (e.g. Neuroform/Boston Sc.; Enterprise/Cordis) dedicated for intracranial use a larger range of wide necked aneurysm can be treated now. A real positive feature is the extreme flexibility of these stents allowing navigation through very tortuous vessels in contrast to formerly used balloon mounted stents. Fortunately, stent placement at a bifurcation site or even covering small perforating arteries does not cause vessel occlusion. Although it is true that long term effects of that stent in intracranial vessels are unknown, midterm results do reveal no late vessel occlusion neither relevant stenosis. Intimal hyperplasia is only rarely observed probably due to little radial forces of these stents. One major advantage of stent treatment in wide necked aneurysms seems to be a lower recanalisation rate. Obviously, we do not exactly know the reason for that but alteration of the inflow and or epithelialisation of the stent might be an explanation. First results using stents of the newest generation are even more promising in preventing aneurysm recanalisation. Those braided stents (Pipeline/Chestnut Med. Tec.; Silk/Balt) are designed to use in the intracranial vasculature and got CE-mark recently. Since the mesh of these stents is very dense covering of side branches and perforators has still to be prove to be safe. A disadvantage of stent treatment is clearly the necessity of antiplatelet therapy. Like in any other case of acute rupture ventricular drainage - if necessary or eventually necessary - should be positioned before endovascular treatment. In such order, parenchymal bleeding is unlikely to occur and stent treatment of acutely ruptured broad based aneurysms in the posterior circulation and infraophthalmic region can at least be considered. Figure 1 Broad based aneurysm treated with microstent (Neuroform, Boston Sc.) and coils. Balloon remodelling would not have guaranteed parent vessel patency. Figure 2 Giant ICA aneurysm treated with (A) Silk stent (Balt), balloon remodelling would not have been an option. Aneurysm (B) before and (C) immediately after stenting showed enormous reduction in flow velocity. Additional coiling was not performed. Nevertheless, we underline that stents should be reserved for patients without other reasonable options since we do not have adequate basic science or controlled clinical evidence to support the routine use of stents in intracranial vessels. However, they are clearly an excellent treatment option in otherwise surgical candidates and - from our experience - can even be used in patients with acute SAH.

Table for Optimization and Monitoring of Cerebral Aneurysm Therapy (TOMCAT)

Several unsolved problems in the treatment of cerebral aneurysms remain that could be addressed in a large multicenter registry. The Table for Optimization and Monitoring of Cerebral Aneurysm Therapy (TOMCAT) was launched to monitor the quality of care in the participating centers (http://www.aneurysma-studie.de). Case record forms (CRFs) were developed in consensus between neuroradiologists and neurosurgeons. CRFs were collected locally and sent to the Center for Neurologic Studies (“Zentrum fur Neurologische Studien” [ZNS]) in Essen, Germany. Initial clinical grade was assessed according to the World Federation of Neurological Surgeons' (WFNS) classification and outcome by the modified Rankin Scale (mRS). An mRS score ≤ 1 was defined as good outcome. After completion of a lead-in phase the database was read out for analysis. Rates of complications and of aneurysm remnants were calculated for anatomic localizations, aneurysm anatomy, and clinical presentation (WFNS). TOMCAT was launched as prospective registry within a single center in 03/2006. With inclusion of more centers, an enrollment rate of 20 patients per month was achieved. A total of 487 patients were included. Complete treatment information was available for 315 (64.7%). In case of completed CRFs, twelve patients were untreated, 278 were treated endovascularly (EVT, among them 86 unruptured aneurysms), and 25 surgically. Stent or balloon remodeling techniques were applied in 3.6% and 3.1% of cases, respectively. Bioactive coils were used in 14.4%. In EVT, the rate of procedural aneurysm perforation was 2.3% (2/86) in unruptured and 4.3% (8/186) in ruptured aneurysms. In unruptured aneurysms the rate of permanent neurologic complications was 3.4%. The rate of residual aneurysms was 14.2%, especially in large and MCA (middle cerebral artery) aneurysms. During the lead-in phase of TOMCAT, a stable enrollment could be established. However, as not all treated patients in the single centers are sent to the central database, only preliminary conclusions can be made. First, there is a low complication rate in unruptured aneurysms. Second, MCA aneurysms still appear to represent a challenge due to high rates of complications and residual aneurysms. Third, no difference was observed in the safety profiles of bare coils and of bioactive coils. An improvement of the data collection is launched with simplified datasets and an alternative electronic submission method together with online analysis tools.