Acta Neurochirurgica The European Journal of Neurosurgery ISSN Acta Neurochir DOI /s

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1 Endovascular treatment of 404 intracranial aneurysms treated with nexus detachable coils: short-term and mid-term results from a prospective, consecutive, European multicenter study Benjamin Gory & Francis Turjman urgica The European Journal of Neurosurgery ISSN DOI /s

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3 DOI /s CLINICAL ARTICLE - VASCULAR Endovascular treatment of 404 intracranial aneurysms treated with nexus detachable coils: short-term and mid-term results from a prospective, consecutive, European multicenter study Benjamin Gory & Francis Turjman Received: 16 September 2013 /Accepted: 20 February 2014 # Springer-Verlag Wien 2014 Abstract Background Aneurysm recanalization remains a limitation of endovascular treatment. A new type of bioactive coil, the polyglycolic/polylactic acid-covered platinum microfilaments Nexus coil (ev3/covidien, Irvine, CA, USA), has been proposed. The objective is to evaluate the safety and short-term and mid-term efficacy of Nexus coils in the endovascular treatment of intracranial aneurysms. Methods The ENDECOR (European Nexus Detachable Coil Registry) is the first prospective, consecutive, multicenter non-randomized registry. After providing informed consent, 390 patients (238 women and 152 men; mean age, 51.6 years) with 404 ruptured or unruptured aneurysms were enrolled at 34 centers. Treatment was performed with at least 75 % of coil length as Nexus coils. Clinical and technical complications were systematically reported. An independent core laboratory evaluated angiographic results by using the Raymond Grading Scale. Results Complete occlusion was seen in 181 aneurysms (48 %); neck remnant in 86 aneurysms (22 %) and aneurysm remnant in 111 aneurysms (30 %). Technical and clinical complications related to the procedure occurred in 33 patients (8.5 %). At discharge, overall mortality and permanentmorbidity were 4.1 % (16/390) and 5.6 % (14/251), respectively. Angiographic mean follow-up of 13.3 months was obtained in 233 of 390 patients (64.4 %) harboring 247 B. Gory (*): F. Turjman Department of Interventional Neuroradiology, Hospices Civils de Lyon, Hôpital Neurologique Pierre Wertheimer, 59 Bd Pinel, Bron, France benjamin.gory@chu-lyon.fr F. Turjman francis.turjman@chu-lyon.fr aneurysms. Recanalization was observed in 44 aneurysms (17.7 %), and progressive thrombosis was observed in 53 aneurysms (21.6 %). Conclusions Endovascular treatment of intracranial aneurysms with Nexus coils was associated with low morbidity and mortality rates. Efficacy of Nexus coils was comparable to published series of intracranial aneurysms treated with bare platinum coils, but their efficacy to prevent aneurysm recanalization was not demonstrated. Keywords Intracranial aneurysms. Coiling. Endovascular treatment. Recanalization Introduction Endovascular treatment (EVT) by using bare platinum coils is now an established technique of both ruptured and unruptured aneurysms [6, 12]. The most significant drawback of endovascular technique is the incidence of aneurysm recanalization over time and may potentially lead to aneurysm rebleeding [14]. This led coil manufacturers to develop modified coils, coating the surface of bare platinum coils with a biodegradable polymer consisting of polyglycolic/polylactic acid (PGA-PGLA), in an effort to improve the angiographic outcomes. The objective of these modified coils was to increase the capacity of healing activator response created by bioabsorbable polymers when compared to coils alone, as demonstrated in animal studies [7, 8]. To date, three randomized trials comparing bioactive coils with bare platinum coils have been reported: thecerecyte Coil trial (494 patients) [5], the Matrix And Platinum Science trial (MAPS, 626 patients) [4] and the HydroCoil Endovascular Aneurysm Occlusion

4 and Packing Study (HELPS, 499 patients) [17]. These trials would suggest that bioactive coils do not improve angiographic follow-up outcomes when compared with bare platinum coils. Nexus detachable coils (ev3/covidien, Irvine, CA, USA) are standard bare platinum coils with additional PGLA microfilament threads interwoven into the primary coil. However, to our knowledge, this coil was evaluated only in one retrospective single-center series [16]. The European Nexus Detachable Coil Registry (ENDECOR) was conducted in 34 centers to evaluate the safety and efficacy of the Nexus coils. The short-term and mid-term results are reported in this article. Material and methods ENDECOR protocol Table 1 Baseline clinical status Baseline neurological status was evaluated by two neurological questionnaires: The Hunt and Hess (HH) and the modified Rankin Scale (mrs). No. % HH grade (n=251) I II III IV V 0 0 mrs (n=283) Thirty-four centers participated in this European, prospective, multicenter, non-randomized study involving the use of the Nexus detachable coils in the treatment of intracranial aneurysms between March 2006 and June 2007 (See Text, Supplemental Content, which illustrates the principal investigators and investigational site). Adult patients with a ruptured or unruptured aneurysm considered suitable for endovascular treatment were included. If treatment of the aneurysm with the Nexus detachable coil system was deemed appropriate, consecutive inclusion of the patients was performed. All patients were treated with Nexus coils alone or in combination with others coils. The recommendation was that 75 % of coil length consng of Nexus coils. Informed consent from the patient was obtained authorizing the collection of data. Exclusion criteria included giant aneurysms (>25 mm), previously treated aneurysms, fusiform morphology, or Hunt and Hess (HH) grade less than IV. The protocol was approved by the Ethics Committee in Essen (Germany), and approved by the French Ministry administration (CCTIRS and CNIL) according to the regulatory requirement. Patients A total of 390 patients (238 women and 152 men; age range, years; mean age, 51.6 years) harboring 404 aneurysms were prospectively included. HH grade and modified Rankin Scale (mrs) are presented respectively in Table 1. A total of 62.4 % of aneurysms (251/402) were ruptured at the time of presentation and among these 29 patients (11.6 %) presented with HH grade IV. Aneurysms The core laboratory was able to analyze the images of 383 aneurysms at baseline. Location of the aneurysms is described in Table 2. Mean aneurysm size was 7.5 mm (min-max, 2 22 mm) and mean neck size was 3.5 mm (min-max, mm). Detailed aneurysm measurement is reported in Table 3. Endovascular procedure All endovascular procedures were performed under general anesthesia and systemic heparinization. A total of 390 procedures were performed. Six patients harboring two aneurysms were treated twice. Coils alone were used in 71.4 % of the procedures. In 86.3 % (341/395) of the procedures, the percentage of Nexus implanted was at least 75 % of the total coil length and this proportion include 72.2 % of cases which only utilized Nexus coils (Table 4). In six cases (1.5 %), no Nexus coils were used due to failure to implant the coil. In 112/392 procedures an adjunctive device was used (28.6 %): a balloon in 20.2 % (79/392), a stent in 5.6 % (22/ 392), a balloon and a stent in 2.6 % (10/392) and a Trispan device in 0.3 % (1/392). Anatomic follow-up Anatomic results were evaluated on angiogram, including selective contrast injections and four projections. For each patient, the postembolization and mid-term degree of aneurysmal occlusion was assessed by the treating neuroradiologist and a second blinded analysis was conducted independently by the core laboratory (Gunnar Wikholm, MD, PhD, Interventional Neuroradiology, Sahlgrenska University Hospital, Göteborg, Sweden). It was defined by using the simplified 3-point Jean Raymond classification scale [14]: complete occlusion, neck remnant, and aneurysm remnant.

5 Table 2 Aneurysm location (n=383) a Location No. % Anterior circulation Internal carotid artery Anterior cerebral artery/acoma b Middle cerebral artery Posterior circulation Posterior cerebral artery/pcoma c Vertebral artery Basilar artery a Data available and analyzed by the core laboratory according to the films provided by the sites correspond to 383 aneurysms. b AComA, anterior communicating artery. Table 4 Percentage of length of Nexus coils (n=395) a No. % 100 % length of Nexus coils % length of Nexus coils <75 % length of Nexus coils % follow-up. Recanalization was defined as a worsening of classification: complete occlusion to neck remnant, neck remnant to aneurysm remnant or complete occlusion to aneurysm remnant. Progressive occlusion was defined as improvement of classification. c PComA, posterior communicating artery. Bleeding/retreatment Bleeding or rebleeding occurrence during the period of follow-up was evaluated. Retreatment of aneurysms during the period of follow-up was also recorded. Data analysis Clinical and procedural data were collected using an electronic Case Report Forms (CRFs) under the supervision of the principal investigator (Francis Turjman). Population analysis was based on the principle of intention-to-treat. All adverse events related to the treatment were reported. Clinical complications were evaluated through systematic neurologic examination. Permanent-morbidity and mortality of EVT were evaluated before and after treatment, at hospital discharge, and at 12-month follow-up. Morbidity was defined as a modified Rankin Scale (mrs) score of 2 to 5. When preoperative mrs was greater than 1, morbidity was defined by any increase of mrs by one point. Any modification within 30 days after EVT was designated as treatmentrelated. Any death within 30 days of endovascular treatment was designated a treatment-related death. Recanalization and progressive occlusion were defined as a change in the Raymond classification, comparing the rate of occlusion postembolization and on mid-term Table 3 Aneurysm measurement (n=379) a a Over the 383 aneurysms evaluated by the core laboratory, measurements were evaluable for 379 aneurysms. Aneurysm No. % Size Neck <10 mm <4 mm mm mm <4 mm mm Results Procedural adverse events Overall, 18 adverse events were reported during the procedure (4.6 %). Seventeen events were reported as related to the procedure (4.3 %). Thirteen were thromboembolic, three of which directly related to coil protusion. Intraprocedural aneurysmal rupture occurred in three cases. Other complications included hydrocephalus in one patient and severe vasospasm induced by the treatment in another patient. All perioperative thromboembolic events were angiographically depicted by the performing investigator and are reported in this series: clotting near the neck of the aneurysm, clotting in the distal branches, and parent vessel occlusion. Treatment of thromboembolic complications was tailored to the specific situation of each patient. In 14 patients, no specific treatment of the thromboembolic event was performed. In three patients, the approach was performed by using mechanical or chemical tools (antiplatelet medication or fibrinolytics). In two patients, stenting was performed. In one patient, medical treatment was modified during the procedure (systemic heparinization and intravenous antiplatelet therapy). One patient died due to bleeding 12 h later after treatment (massive diffuse subarachnoid hemorrhage). Intraprocedural aneurysmal rupture was observed in three patients. Aneurysmal rupture was depicted by the extravasation of contrast media. In one patient, no clinical modification was observed after the perioperative rupture. In one patient, bleeding during balloon angioplasty of severe vasospasm was observed and was responsible for a neurologic deterioration with a permanent neurologic deficit. In one patient, a massive subarachnoid hemorrhage occurred 12 h after treatment and led to death within 24 h. Technical complications were reported during 27 procedures (6.9 %), technical complications reported are: coil stretching (Nexus or bare coil), coil broken, coil stuck in

6 catheter, premature coil detachment, and difficulty detaching coil. In one patient, two technical events occurred during placement of the coil: broken Nexus coil and Nexus coil stuck in catheter, during the procedure, a vasospasm was reported. After this complication, the angiogram post-procedure showed correct flow, but 12 h post procedure the patient experienced a SAH leading to death one day after. Mortality and morbidity At discharge, one patient died (0.2 %) from bleeding occurred during procedure, four had a permanent deficit (1.1 %), and 13 had a transient deficit (3.2 %). Treatment-related mortality was 0.2 % and permanent-morbidity was 1.1 %. Because of the evolution of the SAH, postoperative modification of the clinical status was observed in 22 patients (5.6 %) at discharge (Table 5). Eight additional patients died but their neurological evaluation was not reported by the site. Fifteen deaths occurred in patients presenting ruptured aneurysms (severity of the initial bleeding, vasospasm, massive cerebral edema). At discharge, overall mortality and permanent morbidity were 4.1 % (16/390) and 5.6 % (14/251), respectively. Among the 390 patients who were included in the registry, 21 were dead at one year (16 deaths at discharge, and five deaths at one year post procedure), 120 were lost to follow-up, and seven elected to withdraw from the registry. Finally, 233 patients had one year clinical follow-up (Table 5). Between discharge and one year follow-up, the neurological status of the patients stayed stable or improved for 163 patients (93 %, 163/175). A total of five deaths since discharge are reported at one year follow-up. One is the outcome of an event reported at discharge (encephalitis due to external ventricular drainage, death eight months later), and the four others are related to myocardial infarction, bacterial pneumopathy, or unknown cause. Anatomic results According to the first analysis conducted by the treating neuroradiologist, the postoperative aneurysmal occlusions were the following: complete occlusion, 219 aneurysms (55.2 %); neck remnant, 119 aneurysms (30.0 %); and aneurysm remnant, 59 aneurysms (14.8 %). Results obtained after the independent analysis conducted by the core laboratory were the following (Table 6): complete occlusion, 181 aneurysms (47.9 %); neck remnant, 86 aneurysms (22.7 %); and aneurysm remnant, 111 aneurysms (29.4 %). Among the 404 aneurysms who were initially included in the registry, 247 aneurysms had mid-term anatomic follow-up after treatment (mean, 13.3 months) (Table 7). Thirty-two patients were not controlled by angiography but by MRA due to patient s clinical condition or site organization. Anatomic evaluation at mid-term follow-up according to the aneurysm size is reported in Table 8. The occlusion was stable at one year for 48.2 % of aneurysms. Aneurysm recanalization was observed in 44 aneurysms (17.7 %), and progressive occlusion was observed in 53 aneurysms (21.6 %). Clinical results Three bleedings or re-bleedings were reported. All bleedings occurred before patient discharge and were not due to aneurysm rupture: two following cerebrospinal fluid drainage and one from bleeding at another site location. Retreatment In the group of 204 patients having a 1-year clinical follow-up, retreatment was performed in eight of 260 aneurysms (3.1 %). Retreatment was performed 6 months after the initial treatment in one patient and>6 months after treatment in seven patients. Discussion Aneurysm recanalization remains the most significant limitation of the EVT technique. The bioactive coil concept was developed a few years ago in an effort to improve the angiographic outcomes. Boston Scientific (Fremont, CA, USA) introduced the first PGLA-coated coil (Matrix) on the market in Matrix coils have a reduced amount of metal which is replaced with PGLA polymer resulting in approximately 30 % metal and 70 % PGLA polymer covering the metal coil. However, the efficacy of Matrix coils in preventing Table 5 Evolution of clinical status between baseline and one year follow-up modified Rankin Scale Preprocedure (n=283) Discharge (n=317) 1-year (n=233) (43.8) 180 (56.8) 181 (77.9) 1 93 (32.9) 84 (26.5) 27 (11.6) 2 22 (7.8) 14 (4.4) 8 (3.4) 3 17 (6.0) 7 (2.2) 6 (2.6) 4 14 (4.9) 10 (3.1) 3 (1.3) 5 13 (4.6) 6 (1.9) 3 (1.3) 6 0 (0) 16 (5.1) 5 (1.9)

7 Table 6 Anatomic evolution of aneurysms for Core Laboratory Postprocedural (n=378) 1 year (n=247) No. % No. % Complete occlusion Neck remnant Aneurysm remnant Table 8 Occlusion at one year follow-up according to the aneurysm size for the Core Laboratory (n=247) Size Neck Complete Neck remnant Aneurysm remnant < 10 mm < 4 mm 75 (30.4 %) 59 (23.8 %) 9 (3.6 %) 4mm 28(6.1%) 14(4.0%) 32(8.5%) 10 mm < 4 mm 2 (0.8 %) 6 (2.4 %) 1(0.4 %) 4mm 15(6.1%) 13(5.3%) 4(1.6%) recanalization was not demonstrated as of now [4, 9, 10]. Another modified coil is the Cerecyte coil (Micrus, Sunnyvale, CA, USA), which is a metal coil with PGA filament inside the coil structure. Cerecyte coils did not improve 6- month angiographic outcomes [5]. The Nexus PGLA microfilament coil was introduced by Covidien in However, to date, no consecutive large series reported the safety and efficacy of a new type of bioactive coil: the PGLA microfilaments Nexus coils. ENDECOR is the first prospective, consecutive, European muticentric study of Nexus detachable coils. Unfortunately, among the 390 patients who were included in the registry, 120 were lost to follow-up. Finally, 233 patients had one year clinical follow-up and 247 aneurysms had mid-term anatomic follow-up after treatment. However, these results were systematically evaluated by an independant core laboratory, which seem to be a quality criteria. In a recent meta-analysis, Rezek et al., demonstrated that core laboratories tend to report higher rates of unfavorable outcomes compared with self-reporting centers [15]. Safety of the nexus coils Compared with the unique retrospective single-center series of Van Rooij [16] dealing with 95 aneurysms treated exclusively with Nexus coils, the mortality (0.2 %) and permanentmorbidity rates (1.1 %) we observed are higher. Van Rooij [16] reported no permanent neurological complications occurred in 95 patients with 101 aneurysms. This may be due to the design of our prospective registry, because all adverse events were systematically reported, even when they did not result in a modification of the patient s clinical status. However, no comparison was conducted between ruptured and unruptured aneurysms in our series. Table 7 One-year anatomical results Site (n=247) Core Laboratory (n=247) No. % No. % Complete occlusion Neck remnant Aneurysm remnant Compared with other series of bioactive coils, morbimortality rates observed in our series are relatively similar. In the Cerecyte coil trial, there were no significant differences between groups in the frequency of overall adverse events leading to neurologic deterioration, 10/247 (4.0 %) for Cerecyte and 5/250 (2.0 %) for bare platinum coils (P=.091) [1]. Thus, in this series, the use of Cerecyte coils was not associated with an increased incidence of complications leading to neurologic deterioration. Regarding unruptured aneurysms in the ENDECOR study, the rate of mortality (0.2 %) and permanent-morbidity (1.1 %) were very low. Coley [1] found very close results with no in-hospital mortality and permanent morbidity rate of 2.1 %. In the prospective, multicenter study conducted in France of 244 aneurysms treated with Matrix coils reported by Pierot [10], treatment-related mortality and permanent morbidity rates were 0 % and 1.1 %. In accordance with the data of the literature [3, 6, 9, 10, 12, 14], our results confirm the safety of EVT with a very low rate of treatment-related morbimortality. Short-term efficacy of the nexus coils In our series dealing with the largest number of aneurysms treated with Nexus coils, initial occlusion was complete in 47.9 % of cases and near complete (complete occlusion and neck remnant) in 70.6 % of cases. To date, only one retrospective series has been published regarding the anatomic results after EVT with Nexus coils, and the initial occlusion rate was near complete in 96 % of cases [16]. However, as reported previously, it is difficult to compare the present results with those from previous series because the degree of angiographic occlusion is frequently overestimated by the neuroradiologist treating the patient [10, 15]. In our series, complete occlusion was observed in 55.2 % of cases by the treating neuroradiologist, while a core laboratory found a rate of 47.9 %. In a recent meta-analysis, Rezek [15] suggested that the core laboratory interpretation was significant for unfavorable outcomes (OR, 5.60; 95 % CI, ; P=.001). The ENDECOR study was designed taking into account these parameters, which reduces the bias. Comparing aneurysms treated by Matrix coils, Pierot [9] reported an initial complete and near complete occlusion rate

8 of 44 % and 69 % of cases, respectively. Finally, short-term efficacy of Nexus coils appears in the same range as that of Matrix coils. In addition, the main goal of coiling is the protection against bleeding or re-bleeding. In this series, three bleedings or re-bleedings were reported during mean followup of 13.3 months but were not related to rupture of previously treated aneurysms. Mid-term efficacy of the nexus coils In the series of Van Rooij [16], follow-up angiographic results were obtained in 87 aneurysms treated with Nexus coils, occlusion status was incomplete in 14 aneurysms (16 %) and 12 were additionally coiled. We found a stability of aneurysm occlusion in 48.2 % of patients, a progressive thrombosis in 21.6 %, and a recanalization in 17.7 %. Our results are close to those reported by Ferns [2]. In this systematic review [2], the recanalization rate was 20.8 % at a mean follow-up ranging from 4.7 to 38 months [2]. In addition, Pierot [10] reported similar results with Matrix coils. At mean follow-up of 14 months, of 171 aneurysms, 79 (46.2 %) aneurysms were completely occluded. Recanalization and progressive thrombosis were observed in 44 patients (25.7 %) and 52 aneurysms (30 %), respectively. Thus, our recanalization rate of 17.7 % with Nexus coils was within the range of the previously published series [2, 10, 16]. The use of Nexus coils seems not to influence the midterm recanalization rate of aneurysms. Retreatment Eight aneurysms (3.1 %) were retreated during the period of follow-up. The rate of retreatment varied widely in the different studies. In a systematic review dealing with 8161 coiled aneurysms, Ferns [2] reported a rate of 10.3 %. In the unique series assessing the long-term (mean, 29 months) anatomical results of aneurysms treated exclusively with Matrix coils. Piotin [13] showed a recanalization in 35.6 %. Limitations of the current study Our study has several limitations. First, it was not a randomized study between Nexus coils and bare platinum coils. A second limitation is that ruptured and unruptured aneurysms were included. Clinical and anatomic situations are different in the case of ruptured versus unruptured aneurysms. Rupture and thromboembolic events were more frequent for ruptured aneurysms than for unruptured aneurysms [3]. However, in the cerecyte coils trial, no significant differences in the procedural neurologic complications between the cerecyte and bare platinum coils was demonstrated [1]. In addition, rupture status was not identified as a predictive factors for the occurrence of complications in the Matrix French study [11]. A third limitation is that findings from mid-term and long-term anatomic follow-up were not available. Therefore, the efficacy of the Nexus coils with regard to recanalization cannot be analyzed in this report. Conclusion We have reported short-term and mid-term results of the largest series to date with using Nexus detachable coils for intracranial aneurysm treatment. The Nexus coils demonstrated safety that are comparable to a published series of intracranial aneurysms treated with bare platinum coils. The use of Nexus coils did not influence the mid-term recanalization rate of aneurysms. Acknowledgments We are grateful to all the investigators and coordinators for the support and hard work in enrolling patients, completing data collection forms, and participating in the study. Principal investigators and Investigational site Supplemental Content. Text that illustrates the principal investigators and investigational sites: The principal investigators and the investigational site are listed with total patients enrolled in each center in parentheses. Francis Turjman, Benjamin Gory, Roberto Riva, Hôpital Neurologique, Lyon, France (20); Paolo Apolito, ASL Napoli 1, Napoli, Italy (32); Joachim Klisch, Helios Klinikum Erfurt, Erfurt, Germany (28); André Gaston, Hôpital Henri Mondor, Créteil, France (27); Gyula Gal; Akademiska Sjukhuset, Uppsala, Sweden (20); Maurizio Resta, Ospedale SS. Annunziata, Taranto, Italy (20); Xavier Barreau, Jérôme Berge, Groupe Hospitalier Pellegrin, Bordeaux, France (19); Martin Skalej, Universität Medizinische Fakultät, Magdeburg, Germany (17); Istvan Lazar, Borsod Teaching Hospital, Miskolc, Hungary (16); Karlis Kupcs, Pauls Stradins Clinical University Hospital, Riga, Latvia (16); Vasilios Katsaridis, Papanikolaou General Hospital, Thessaloniki, Greece (15); Patrick Courthéoux, Hôpital de la Côte de Nacre, Caen, France (14); Christophe Cognard, Hôpital Purpan, Toulouse, France (14); Alain Bonafé, Hôpital Gui de Chauilac, Montpellier, France (13); Alexandra Biondi, Fabrice Bonneville, Nader Sourour, Hôpital Pitié Salpétrière, Paris, France (12); Ignacio Hernando, Ricardo Ituarte; Eva Gonzalez Díaz, Hospital de Cruces, Bilbao, Spain (13); Luis López-Ibor, IDC Recoletas, Albacete, Spain (12); Per Jonasson, Norrlands Universitetssjukhus, Umeå, Sweden (10); Antonio Romance, Hospital Carlos Haya, Malaga, Spain (10); Denis Herbreteau, Hôpital Bretonneau, Tours, France (9); Laurent Pierot, CH de Reims, Hôpital de la Maison Blanche, Reims, France (9); Pierre Goffette, CH Saint Luc, Bruxelles, Belgium (9); Juan Macho, Hospital Clinic i Provincial, Barcelona, Spain (8); Serge Bracard, René Anxionnat, Ariel Lebedinski, Hôpital Central, Nancy, France (8); Wolfgang Reith, Universität des Saarlandes, Homburg, Germany (7); José Luis Caniego, Hospital la Princesa, Madrid, Spain (8); Marciej Szajner, Samodzielny Publiczny Szpital Kliniczny, Lublin, Poland (4); Elisa Ciceri, Istituto Neurologico C. Besta, Milano, Italy (3); Michael Forsting, Isabel Wanke, Universitätsklinikum Essen, Essen, Germany (3); René Chapot, Hôpital Dupuytren CHU, Limoges, France (2); Günther Erich Klein, LKH Graz/Universitätskliniken, Graz, Austria (2); Pietro Amista, Neuroradiologia, Azienda Ospedaliera di Padova, Padova, Italy (1); Javier Masso, Jose Angel Larrea, Hospital Donastia, San Sebastian, Spain (1); and Vaclav Procházcka, Faculty Hospital Ostrava Poruba, Czeckoslovakyia Republic (1). Conflicts of interest None.

9 References 1. Coley S, Sneade M, Clarke A, Mehta Z, Kallmes D, Cekirge S, Saatci I, Roy D, Molyneux A (2012) Cerecyte coil trial: procedural safety and clinical outcomes in patients with ruptured and unruptured intracranial aneurysms. AJNR Am J Neuroradiol 33: Ferns SP, Sprengers ME, van Rooij WJ, Rinkel GJE, van Rijn JC, Bipat S, Sluzewski M, Majoie C (2009) Coiling of intracranial aneurysms: a systematic review on initial occlusion and reopening and retreatment rates. Stroke 40: Henkes H, Fischer S, Weber W, Miloslavski E, Felber S, Brew S, Kuehne D (2004) Endovascular coil occlusion of 1811 intracranial aneurysms: early angiographic and clinical results. Neurosurgery 54: Matrix and Platinum Science (MAPS) (2011) Abstract. Eighth Annual Meeting of the Society of Neurointerventional Surgery (SNIS); Colorado Springs, CO; July Molyneux AJ, Clarke A, Sneade M, Mehta Z, Coley S, Roy D, Kallmes DF, Fox AJ (2012) Cerecyte coil trial: angiographic outcomes of a prospective randomized trial comparing endovascular coiling of cerebral aneurysms with either cerecyte or bare platinum coils. Stroke 43: Molyneux AJ, Kerr R, Stratton I, Sandercock P, Clarke M, Shrimpton J, Holman R, International Subarachnoid Aneurysm Trial (ISAT) Collaborative Group (2002) International Subarachnoid Aneurysm Trial (ISAT) of neurosurgical clipping versus endovascular coiling in 2143 patients with ruptured intracranial aneurysms: a randomised trial. Lancet 360: Murayama Y, Vinuela F, Tateshima S, Gonzalez NR, Song JK, Mahdavieh H, Iruela-Arispe L (2002) Cellular responses of bioabsorbable polymeric material and Guglielmi detachable coil in experimental aneurysms. Stroke 33: Murayama Y, Tateshima S, Gonzalez NR, Vinuela F (2003) Matrix and bioabsorbable polymeric coils accelerate healing of intracranial aneurysms: long-term experimental study. Stroke 34: Pierot L, Bonafé A, Bracard S, Leclerc X, French Matrix Registry Investigators (2006) Endovascular treatment of intracranial aneurysms with Matrix detachable coils: immediate posttreatent results from a prospective multicenter registry. AJNR Am J Neuroradiol 27: Pierot L, Leclerc X, Bonafé A, Bracard S, French Matrix Registry Investigators (2008) Endovascular treatment of intracranial aneurysms with Matrix detachable coils: midterm anatomic follow-up from a prospective multicenter registry. AJNR Am J Neuroradiol 29: Pierot L, Leclerc X, Bonafé A, Bracard S, French Matrix Registry Investigators (2008) Endovascular treatment of intracranial aneurysms using Matrix coils: short- and mid-term results in ruptured and unruptured aneurysms. Neurosurgery 63: Pierot L, Spelle L, Vitry F, ATENA Investigators (2008) Immediate clinical outcome of patients harboring unruptured intracranial aneurysms treated by endovascular approach: results of the ATENA trial. Stroke 39: Piotin M, Pistocchi S, Bartolini B, Blanc R (2012) Intracranial aneurysm coiling with PGLA-coated coils versus bare platinum coils: long-term anatomic follow-up. Neuroradiology 54: Raymond J, Guilbert F, Weill A, Georganos SA, Juravsky L, Lambert A, Lamoureux J, Chagnon M, Roy D (2003) Long-term angiographic recurrences after selective endovascular treatment of aneurysms with detachable coils. Stroke 34: Rezek I, Mousan G, Wang Z, Murad MH, Kallmes DF (2013) Effect of core laboratory and multiple-reader interpretation of angiographic images on follow-up outcomes of coiled cerebral aneurysms: a systematic review and meta-analysis. AJNR Am J Neuroradiol 34: Van Rooij WJ, de Gast AN, Sluzewski M (2008) Results of 101 aneurysms treated with polyglycolic/polylactic acid microfilament nexus coils compared with historical controls treated with standard coils. AJNR Am J Neuroradiol 29: White PM, Lewis SC, Gholkar A, Sellar RJ, Nahser H, Cognard C, Forrester L, Wardlaw JM, HELPS trial collaborators (2011) Hydrogel-coated coils versus bare platinum coils for the endovascular treatment of intracranial aneurysms (HELPS): a randomised controlled trial. Lancet 377: