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Mechanical Thrombectomy for Acute Ischemic Stroke Amid the COVID-19 Outbreak

Decreased Activity, and Increased Care Delays
and the SFNR, the ETIS registry, and the JENI-Research Collaborative
Originally published 2020;51:2012–2017


    Background and Purpose:

    The efficiency of prehospital care chain response and the adequacy of hospital resources are challenged amid the coronavirus disease 2019 (COVID-19) outbreak, with suspected consequences for patients with ischemic stroke eligible for mechanical thrombectomy (MT).


    We conducted a prospective national-level data collection of patients treated with MT, ranging 45 days across epidemic containment measures instatement, and of patients treated during the same calendar period in 2019. The primary end point was the variation of patients receiving MT during the epidemic period. Secondary end points included care delays between onset, imaging, and groin puncture. To analyze the primary end point, we used a Poisson regression model. We then analyzed the correlation between the number of MTs and the number of COVID-19 cases hospitalizations, using the Pearson correlation coefficient (compared with the null value).


    A total of 1513 patients were included at 32 centers, in all French administrative regions. There was a 21% significant decrease (0.79; [95%CI, 0.76–0.82]; P<0.001) in MT case volumes during the epidemic period, and a significant increase in delays between imaging and groin puncture, overall (mean 144.9±SD 86.8 minutes versus 126.2±70.9; P<0.001 in 2019) and in transferred patients (mean 182.6±SD 82.0 minutes versus 153.25±67; P<0.001). After the instatement of strict epidemic mitigation measures, there was a significant negative correlation between the number of hospitalizations for COVID and the number of MT cases (R2 −0.51; P=0.04). Patients treated during the COVID outbreak were less likely to receive intravenous thrombolysis and to have unwitnessed strokes (both P<0.05).


    Our study showed a significant decrease in patients treated with MTs during the first stages of the COVID epidemic in France and alarming indicators of lengthened care delays. These findings prompt immediate consideration of local and regional stroke networks preparedness in the varying contexts of COVID-19 pandemic evolution.


    Eligibility for mechanical thrombectomy of patients with acute ischemic stroke (AIS) due to emergent large intracranial vessel occlusion (LVO) is highly dependent on time delays,1 and in turn on the efficiency of prehospital care chain response as well as the adequacy of resources at hospital arrival. Both are likely impacted by the tensions on various components of healthcare systems amid the coronavirus disease 2019 (COVID-19) outbreak. In the current context, there has indeed been anecdotal reports of decreases in activity and lengthening of care delays2 in various sectors of emergent care unrelated to COVID-19, with potentially alarming public health consequences.

    Epidemic response measures for COVID-19 containment were triggered in France on March 1 and gradually escalated until March 15 when nationwide strict home confinement was instituted for propagation mitigation, as the regional and national outbreaks evolved. The unprecedented surge in hospitalizations and emergency medical system activity represents a major stress for the care chain of acutely ill patients, including patients with neurovascular emergencies especially when requiring acute revascularization treatments. Yet specific coordinated data are lacking while they may inform emergent policies.3

    We conducted a prospective national-level study of data from patients with AIS-LVO treated with mechanical thrombectomy (MT) ranging 15 days before to 30 days after strict containment measures instatement and compared it to data of patients treated with MT during the same calendar period in 2019. We tested the hypothesis that the COVID-19 outbreak would impact negatively the number of patients with AIS-LVO treated with MT, and that care delays would be lengthened. We then explored the correlation between the total number of hospitalizations for COVID-19 and the decrease in MT activity across the country, and finally analyzed variations in patients’ clinical-imaging profile during the ascending epidemic period.


    Data Collection

    According to the AHA Journals’ implementation of the Transparency and Openness Promotion Guidelines, all data and materials can be accessed by request from the corresponding author ().

    French MT capable stroke centers were invited to prospectively collect de-identified data through 2 existing research networks: the JENI—SFNR (Jeunes en Neuroradiologie Interventionnelle) research collaborative4 and the Endovascular Treatment of Ischemic Stroke registry,5 under the aegis of the SFNR (French Neuroradiological Society).

    The prospective data acquisition period ranged from February 15, 2020 to March 30, 2020 (15 days prior the epidemic containment measures initiation, to 15 days after mitigation measures were instituted). Retrospective data acquisition covered the same calendar period in 2019.

    All centers were asked to answer a short survey about local modifications in department organizations, COVID triage means in the context of AIS, changes in adherence to guidelines for MT indication, and anesthetic considerations.


    All patients with AIS-LVO receiving MT were included. Two case report forms were provided to account for the limited local capacities of time-consuming data acquisition in the context. The simplified version only recorded the dates when MT were performed at each center. In the complete case report form, we collected dates, de-identified demographics, COVID-19 status, vascular risk factors, clinical (National Institutes of Health Stroke Scale) and radiological (Alberta Stroke Program Early CT Score6) severity at presentation, delays between onset, imaging, intravenous thrombolysis and MT start, and clinical severity at discharge or last follow-up.

    Study End Points

    The primary end point was the comparison of the total number of patients receiving MT between study periods. Secondary end points were (1) the delay between symptoms onset (or symptoms discovery for patients with unwitnessed stroke onset) and imaging initiation as well as (2) thrombolysis initiation, and (3) the delay between imaging initiation and MT start (groin puncture). We also tested variations in patients’ characteristics across study periods. Finally, we analyzed the correlation between the total number of hospitalizations for COVID-19 (from governmental open-license data available at and the number of MT cases nationally.


    Categorical variables are expressed as numbers (%) and continuous data as medians (interquartile range) as appropriate. To test the impact of the outbreak on MT case volume and patients characteristics, we analyzed the data in the following ways. To analyze the primary end point, we used a Poisson regression model, adding as offset the number of stroke inpatients by region in 2016 (data available at and sought to quantify the difference in the number of strokes between 2019 and 2020.

    Focusing on the epidemic period, we then use mixed models to look for regional changes across the data acquisition window and analyzed the global correlation between the number of MTs and the number of COVID-19 cases, using the Pearson correlation coefficient (compared with the null value).

    Finally, to analyze the differences in patients’ characteristics between 2019 and 2020, we compared categorical variables using the χ2 or Fisher exact test and quantitative variables using the Student t test or the Wilcoxon rank-sum test. All the analyses were performed with the software r version 3.6.0. The threshold for statistical significance was set at 0.05.


    As for all noninterventional studies of de-identified data in France, written informed consent was waived and a commitment to compliance (Reference Methodology CPMR-4, No. 2217365) was filed to the French National Information Science and Liberties Commission/National Institute for Healthcare data before data centralization, in respect to the General Data Protection Regulation. Patients or proxies were informed they could oppose the use of their data. This report was prepared according to the Strengthening the Reporting of Observational Studies in Epidemiology statement.7


    A total of 1513 patients were included at 32 centers, in all French administrative regions (Figure I in the Data Supplement displays the geographic distribution) over the 2 study periods. Over the epidemic period, 10 patients with biologically proven COVID-19 infection were treated with MT at 7 centers.

    Primary End Point: Case Volume

    Eight hundred and forty-four (55.8%) patients were treated in 2019 and 668 (44.2%) in 2020, representing an overall 20.9% drop in patients receiving MT during the COVID period. This constituted a significant variation using Poisson regression when compared with 2019 similar calendar period (0.79; [95% CI, 0.76–0.82]; P<0.001). Mixed models did not identify significant individual regional variations, likely due to limited sub samples.

    Correlation Between MT Cases Volume and COVID-19 Hospitalizations

    The Figure is a visual representation of case volume evolution over the study period, showing a marked drop after March 15, date of mitigation measures initiation. Over the entire 2020 period, there was a weak negative correlation between the total number of hospitalizations for COVID and the number of MT cases in France (R2: −0.27, P=0.07 for the comparison with 0), yet after March 15, that is during the steepest progression in hospitalization cases and after instatement of the mitigation measures, the correlation strengthened to R2: −0.51 and became significant (P=0.04).


    Figure. Visual representation of daily mechanical thrombectomy (MT) cases and coronavirus disease 2019 (COVID-19) hospitalizations.

    Secondary End Points: Delays

    Complete case report form was available from 17 centers (Figure I in the Data Supplement), totalizing 864 patients for whom the comparison between 2019 (n=477) and 2020 (n=387) is presented in the Table and below.

    Table. Baseline Characteristics of Included Patients With Complete CRF

    2019, n=4772020, n=387P Value
    Patients characteristics
     Sex, female41.6% (199/477)48.8% (189/387)0.034
     Hypertension60.7% (280/461)58.3% (214/367)0.47
     Diabetes mellitus19.1% (86/450)18.3% (67/366)0.769
     Dyslipidemia30.4% (136/447)29.5% (108/366)0.777
     Tobacco use (current or past)25% (109/436)25.1% (89/354)0.964
     Atrial fibrillation35.4% (130/367)29% (104/359)0.063
    Stroke management
     Baseline NIHSS14.8±6.8; n=46215.3±6.8; n=3770.279
     Baseline MRI (vs CT)84.3% (391/464)83.4% (321/385)0.726
     ASPECTS7 [6–9]; n=3907 [6–8]; n=3440.041
     Unwitnessed onset37.5% (166/443)30.6% (115/376)0.004
     IVT51% (240/471)43.5% (166/382)0.029
     ICA occlusion123/418 (29%)111/370 (30%)0.657
     MCA occlusion257/418 (61%)232/370 (63%)
     Posterior circulation38/418 (9%)27/370 (7%)
     Tandem occlusion15.2% (63/415)15.9% (59/370)0.768
     Inter-hospital transfer after imaging60% (285/475)58.6% (225/384)0.677
     Symptom-onset* to imaging147.5±89.8; n=444143.3±96.7; n=3630.524
     Imaging to groin delay126.2±70.9; n=451144.9±86.8; n=374<0.001
     Imaging to groin delay if transfer153.25±67.48; n=261182.56±81.98; n=220<0.001
     Symptom-onset/last-seen well to needle163.9±54.3; n=226164.6±57; n=1580.907
    Preliminary outcome measures0
     Successful reperfusion (mTICI 2b–3)82% (361/440)82.3% (311/378)0.932
     Latest NIHSS11±10.7; n=36410.3±10.3; n=2530.775
     In-hospital mortality17.3% (59/341)12.9% (37/287)0.124

    Values are expressed as mean±SD, median with interquartile range (IQR), or absolute value (percentage). ASPECTS indicates Alberta Stroke Program Early CT Score; ICA, internal carotid artery; IVT, intravenous thrombolysis; MCA, middle cerebral artery; MRI, magnetic resonance imaging; mTICI, modified Treatment in Cerebral Infarction; and NIHSS, National Institutes of Health Stroke Scale.

    *Or symptoms discovery if unwitnessed stroke.

    During the COVID period, there was a significant increase in delays between imaging and groin puncture, overall (mean 144.9±SD 86.8 minutes versus 126.2±SD in 2019; P<0.001) and in patients transferred for MT after imaging (mean 182.6±SD 82.0 minutes versus 153.25±67 in 2019; P<0.001). In contrast, in patient receiving MT at the stroke center of initial presentation (ie, mothership subgroup) the delays between imaging and groin puncture did not increase significantly between 2019 and 2020 (mean 138±SD 96.02 minutes versus 144.6±SD 90.7 in 2019; P=0.5519). The increase between imaging and groin puncture delay in patients requiring inter-hospital transfers was most marked in the Grand-Est region (141.9±9.2 minutes in 2020 versus 107.9±8.9 minutes in 2019, P<0.001), the most prematurely COVID-19 region impacted in our country. We did not observe differences between symptoms onset (or symptoms discovery if unwitnessed onset) and imaging in the entire sample or in transferred patients. See the Table for details.

    Exploratory Analysis: Variations in Patients Characteristics

    Patients treated in 2020 presented with lower Alberta Stroke Program Early CT Scores (median, 7; interquartile range, [6–8] versus 7 [6–9]; P=0.041), less frequent unwitnessed onset (30.6% versus 37.5%, P=0.004). They less frequently received intravenous thrombolysis (43% versus 51%; P=0.029) before MT. The rate of inter-hospital transfers was similar between study periods, and there was no difference in preliminary outcome measures with comparable latest National Institutes of Health Stroke Scale (10.3±10.3 versus 11±10.7; P=0.775), a similar rate of successful reperfusion (82.3% versus 82%; P=0.932), and in-hospital mortality (12.9% versus 17.3%; P=0.124). See the Table for details.

    Local Adaptations to the COVID-19 Situation

    Among the 32 strokes centers, 21 replied to the survey aimed to assess the local adjustments of in-hospital management of patients requiring MT (See complete survey in Appendix I in the Data Supplement). Twenty centers (20/21, 95%) had postponed their elective activity as of March 16. Seventeen centers (17/21, 80.9%) reported serious alterations in the anesthesia and critical care departments, with indirect consequences on MT in-hospital workflow.

    Clinical signs of COVID-19 and potential contact with infected people were systematically sought by questioning patient or their relatives before MT in 19 centers (19/21, 90.5%).

    Patients with suspected or proven COVID-19 infection were treated in a dedicated angio-suite in 5 centers (5/21, 23.8%). Chest-CT-Scanner were performed systematically before MT in 2 centers (2/21, 9.5%) and only if COVID-19 infection was suspected or proved in 15 centers (15/21, 71.4%).

    Ten centers (10/21, 47.6%) declared that they restrained MT indications to the strict application of practice guidelines.


    Here we provide important information on the impact of COVID-19 on MT case volumes and volume evolution over the first 45 days of the epidemic at a national level. The main result of this pilot study is the 21% decrease in overall volume of patients with AIS-LVO receiving MT during the epidemic period when compared with 2019.

    While we are unable to assert that this is not a random fluctuation, the decrease of MT cases volumes after March 15 as the number of COVID-19 related hospitalization steeply increased and the concurrent strengthening of the negative correlation between these 2 parameters after this date plead for an indirect causation. Further, the total number of MTs has increased in France by 23% in 2018, and 15% in 2019 (Internal SFNR data) hence the volume case evolution trend was expected to be ascending in 2020 regardless of the calendar period.

    Several speculative factors may explain to some extent these findings. The most plausible one, is that amid the unprecedented stress on emergency medical system services, primary care stroke centers may struggle to access transfer resources needed to send MT eligible patients to referring thrombectomy capable stroke centers within the therapeutic window. In turn, it may well be that patients with indications outside of strict guidelines may have not been referred or accepted for MT.

    This is reinforced by another alarming finding: delays between imaging and groin puncture have increased significantly between 2019 and 2020 in transferred patients (+29 minutes), while it did not in patient receiving MT at the stroke center of initial presentation (ie, no measurable increase in intrahospital delays). This likely reflects to some extent the saturation of health transportation system capacity as a result of the crisis. Reinforcing this assertion is the fact that the Grand-Est region, first affected in France, showed the most important difference in time delays.

    Another concurring factor may be more stringent application of practice guidelines in the tensed context. Indeed, while only a single center declared that 1 patient was recused for MT due to concurrent life-threatening acute respiratory distress syndrome in the context of a COVID-19 infection, in the accompanying survey, almost 50% of responding centers declared that they altered their selection process to strict adherence to practice guidelines during the epidemic period. Finally, another putative reason to explain our findings might be that patients’ or families’ fear of COVID-19 contamination risk at hospital may have led to delaying their hospital presentation or call to emergency medical system.

    Additional findings from this report include the decrease in both unwitnessed-onset strokes and number of patients receiving intravenous thrombolysis before MT in the epidemic period. As there were no assumptions regarding both variables, these results are hypothesis-generating, rather than expected. It may reinforce the postulation that in the epidemic context, patients with borderline indications (eg, unwitnessed strokes not strictly meeting extended window criteria) may have not been addressed or may have been excluded due to stricter adherence to practice guidelines. Social distancing in isolated individuals may also have resulted in prolonged delays, leading to ineligibility for MT, but we acknowledge that this is speculative.

    Altogether, this reports provides a preliminary data-driven framework to inform policies and local responses for the emergent care of patients with AIS due to LVO as the pandemic evolves.

    These results may be perceived as a stopgap in a rapidly evolving situation, nonetheless they provide coordinated national-level data, and may help regions yet not severely affected with COVID-19 with thorough analysis of potential collateral consequences of the pandemic on patients with severe strokes. It is, further, likely that not only the number of patients treated with MT decreased, but that there’s an overall broader impact on all emergent care chains beyond the immediate infection (as has been reported for instance in patients with acute myocardial infarction in Hong Kong),2 with mid- and long-term public health consequences.

    This report has limitations, inherent to its design and the expedited nature of data collection. The results are indeed not directly generalizable to other countries, with distinct stroke care systems, and geographic specificities. It is possible that the decrease in case volume may be eventually compensated as the systems adapt in real time to the epidemic situation, maturing work-around solutions. Again, no direct causation can be inferred from these results, which should be considered with caution.


    Our study showed a significant decrease in patients treated with MTs during the first steps of the COVID epidemic in France and alarming indicators of lengthened care delays. These findings prompt immediate consideration of local and regional stroke networks preparedness in the varying contexts of COVID-19 pandemic evolution. Solutions, in the unprecedented public health emergency are likely to vary locally and regionally but considering alternate or dedicated emergency medical system pathways for (neuro)vascular emergencies may help maintain case volumes and continuity of care. Extended monitoring of the situation will give further insight on the public health consequences, outside the infection itself, for patients with AIS.


    List of Collaborators

    Cyril Chivot, Riyad Hanafi, Anne Pasco, Jean-Baptiste Girot (Interventional Neuroradiology Department, CHU Amiens, France); Alessandra Biondi, Fortunato Di Caterino, Panagiotis Primikiris, Giovanni Vitale (Service de Neuroradiologie Interventionnelle, CHU Besançon 3 boulevard Fleming 25000 Besançon); Louise Bonnet (Neurology Department, CHU Besançon 3 boulevard Fleming 25000 Besançon); Florent Gariel, Xavier Barreau, Sabrina Debruxelles, Ludovic Lucas, Patrice Menegon, Stéphane Olindo, Mathilde Poli, Pauline Renou, Sharmila Sagnier, Igor Sibon, Louis Veunac (Interventional Neuroradiology Department, CHRU Bordeaux France); Jean-Christophe Gentric (Service d’Imagerie Médicale, Centre Hospitalier Régional Universitaire de Brest, France); Charlotte Barbier, Marion Boulanger, Julien Cogez, Sophie Guettier, Romain Schneckenburger, Emmanuel Touze (Interventional Neuroradiology Department, CHRU Caen, France); Mariette Delaitre, Pablo Lebendinsky, Mariano Musacchio (Service de Neuroradiologie Diagnostique et Interventionnelle des Hôpitaux Civils de Colmar, 39 avenue de la Liberté, Colmar); Frédéric Ricolfi, Pierre Thouant (Neuroradiology Department, CHRU Dijon, France); François Caparros, Barbara Casolla, Lucie Della Schiava, Nelly Dequatre, Hilde Henon, Marco Pasi, Charlotte Cordonnier (Stroke Unit, CHRU Lille, France); Apolline Kazemi, Fouzi Bala, Laurent Estrade (Interventional Neuroradiology Department, CHRU Lille, France); Charbel Mounayer, Susanna Saleme, Francisco Macian-Montoro (Interventional Neuroradiology Department, CHU Limoges, France); Omer Eker, François Cotton, Karine Blanc-Lasserre, Serkan Cakmak, Tae-Hee Cho, Laurent Derex, Anne-Claire Lukaszewicz, Laura Mechtouff, Norbert Nighoghossian, Frédéric Philippeau, Roberto Riva, Francis Turjman, Anne-Evelyne Vallet (Interventional Neuroradiology Department, CHU Lyon, France); Xavier Carle, Philippe Dory-Lautrec, Anthony Reyre, Jean-François Hak, Hervé Brunel (Interventional Neuroradiology Department, CHRU Marseille La Timone, France); Amel Benali, François-Louis Collemiche, Cyril Dargazanli, Frederico Cagnazzo, Imad Derraz, Caroline Arquizan, Lucas Corti, Vincent Costalat, Nicolas Gaillard, Grégory Gascou, Pierre-Henri Lefèvre, Isabelle Mourand, Carlos Riquelme (Interventional Neuroradiology Department, CHRU Montpellier, France); Anne Laure Derelle, Benjamin Gory, Liang Liao, Romain Tonnelet, René Anxionnat, Mathieu Bonnerot, Serge Bracard, Marc Braun, Lisa Humbertjean, Jean-Christophe Lacour, Gioia Mione, Sophie Planel, Sébastien Richard, Nolwenn Riou-Comte, Emmanuelle Schmitt (Service de Neuroradiologie Diagnostique et Thérapeutique CHRU Nancy); Romain Bourcier, Lili Detraz, Hubert Desal, Pierre-Louis Alexandre, Benjamin Daumas-Duport, Cédric Lenoble, Monica Roy (Interventional Neuroradiology Department, CHU Nantes, France); Jacques Sedat (Interventional Neuroradiology Department, CHU Nice, France); Oghuzan Coskun, Frederico Di Maria, Bertrand Lapergue, Georges Rodesch, Adrien Wang, David Weisenburger-Lile, Sergio Zimatore, Nadia Ajili, Géraldine Buard, Serge Evrard, Lucas Gorza, Julie Gratieux, Morgan Leguen, Sylvie Marinier, Fernando Pico, Roxanna Poll, Haja Rakotoharinandrasana, Philippe Tassan, Maya Tchikviladze (Stroke Unit, CH Foch, Suresnes, France); François Delvoye, Solène Hebert, Raphaël Blanc, Gabriele Ciccio, Jean-Philippe Desilles, Benjamin Maier, Mikael Mazighi, Michel Piotin, Hocine Redjem, Stanislas Smajda, Malek Ben Maacha (Interventional Neuroradiology Department, Fondation Rothschild, Paris, France); Ovide Corabianu (Neurology Department, Rober Ballanger, Aulnay Sous Bois, France); Thomas De Broucker (Neurology Department, Centre Hospitalier Saint-Denis, Saint-Denis, France); Olivier Ille (Neurology Department, Hopital de Mantes La Jolie, Mantes La Jolie, France); Eric Manchon (Neurology Department, Hopital de Gonesse, Gonesse, France); Michael Obadia, Mickael Obadia, Igor Raynouard, Roxanne Peres, Candice Sabben, Didier Smadja (Neurology Department, Fondation Rothschild, Paris, France); Guillaume Taylor, Laurie-Anne Thion (Anaesthesiology Department, Fondation Rothschild, Paris, France); Augustin Lecler (Neuroradiology Department, Fondation Rothschild, Paris, France); Laurent Spelle, Christian Denier, Jildaz Caroff, Olivier Chassin, laurent Spelle, Laura Venditti (Interventional Neuroradiology Department, Kremlin Bicêtre Hospital, Bicêtre, France); Armand Aymard, Jean Betty, Vittorio Civelli, Michael Eliezer, Matteo Fantoni, Emmanuel Houdart, Marc-Antoine Labeyrie, Jean-Pierre Saint Maurice (Department of Neuroradiology, Lariboisière Hospital, Paris, France); Erwah Kalsoum, Aurelien Pacini, Chawkat Ramadane, Titien Tuilier, Adrien Villain (Service de Neuroradiologie Diagnostique et Interventionnelle, CHU Créteil, Créteil, France); Frédéric Clarencon, Vincent Degos, Ahmed Elhfnawy, Mahmoud Elhorany, Stéphanie Lenck, Kevin Premat, Nader-Antoine Sourour (Department of Neuroradiology, Pitié-Salpêtrière Hospital, Paris, France); Sonia Alamowitch (Department of Vascular Neurology, Saint-Antoine University Hospital, Paris, France); Flore Baronnet, Sophie Crozier, Sandrine Deltour, Anne Leger, Charlotte Rosso (Urgences Cerebro-Vasculaires de la Pitié-Salpetriere APHP & Sorbonne Université, Paris France); Sandrine Deltour, Anne Leger, Charlotte Rosso, Nadya Pyatigorskaya (Department of Neuroradiology, Pitié-Salpêtrière Hospital, Paris, France); Christine Rodriguez Regent, Denis Trystram, Olivier Naggara, Pierre Seners, Guillaume Turc, Myriam Edjlali, Rémi Agbonon, Mohammed Alotaibi, Antoine Sonchet, Catherine Oppenheim, Jean François Meder, Joseph Benzakoun, Laurence Legrand (Department of Neuroradiology and Neurology, Paris Descartes University, INSERM U1266, DHU Neurovasculaire, Sainte-Anne Hospital, Paris); Cédric Fauché, Stéphane Velasco (Service d’Imagerie Médicale CHU de Poitiers); Pierre François Manceau, Sebastien Soize, Solène Moulin (Interventional Neuroradiology Department, CHU de Reims, France); François Eugene, Jean-Christophe Ferre, Christophe Paya, François Eugene, Jean-Yves Gauvrit, Sophie Langnier-Lemercier, Maria Lassale, helene Raoult, thomas Ronziere, Clément Tracol, Stéphane Vannier (Interventional Neuroradiology Department, Neurology Department; CHU Rennes, France); Julien Burel, Julien Le Moal, Chrysanthi Papagiannaki (Interventional Neuroradiology Department, CHU Rouen, France); Mohamed Aggour, Marina Sachet, Claire Boutet (Interventional Neuroradiology Department, CHU Saint Etienne, France); Remy Beaujeux, Anca Hasiu, Monica Manisor, Dan Mihoc, Stéphane Kremer (Service de Neuroradiologie Interventionnelle Hopitaux Universitaires de Strasbourg); Charles Arteaga, Sébastien Gazzola (Interventional Neuroradiology Department, CH Toulon, France); Jean Darcourt, Christophe Cognard, Fabrice Bonneville, Anne Christine Januel, Jean-Marc Olivot, Nicolas Raposo, Alain Viguier (Interventional Neuroradiology Department, Neurology Department; CHU Toulouse, France); Richard Bibi, Fakhreddine Boustia, Denis Herbreteau, Igor Maldonado, Ana-Paula Narata (Interventional Neuroradiology Department, CHRU Tours, France); and Anthony Le Bras (Interventional Neuroradiology Department, CH Vannes, France).


    *A list of all SFNR, the ETIS registry, and the JENI-Research Collaborative members is given in the Appendix.

    For Sources of Funding and Disclosures, see page 2017.

    The Data Supplement is available with this article at

    Correspondance to: Grégoire Boulouis, MD, MSc, Neuroradiology Department, GHU-Paris, 1 rue Cabanis, 75014 Paris. Email


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