Evidence map›Paper›PMID 37284876›Full record

ArticleClinical neuroradiology2023

What is a Challenging Clot? : A DELPHI Consensus Statement from the CLOTS 7.0 Summit.

Johanna M Ospel, Mahmood Mirza, Frédéric Clarençon, Adnan Siddiqui, Karen Doyle, Arturo Consoli, Maxim Mokin, Teresa Ullberg, Osama Zaidat, Romain Bourcier and 31 more

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Article in Clinical neuroradiology, 2023. The graph could read no effect estimate from its abstract, so it casts no vote on the map. Cited by 4 papers.

0numbers the graph read from it
0cells of the map it votes in
4citing papers in PubMed
–field-weighted citation impact
1 · What the graph read from it

What it found

Each row is one number read from the abstract, on the scale the paper reported it, with its interval. Left of the dashed line favours the treatment, right favours the comparator. Under each row is the sentence it came from. New to these charts? A ten-minute tutorial.

The abstract states no effect estimate the extractor could read, or names no intervention and outcome on the map, so this paper lights no cell and moves no belief. It is still indexed, cited and linked below.

2 · The registry

The trial behind it

Trials whose registry record cites this paper, or whose number appears in the abstract. A trial that started after this paper was published is citing it as background, not reporting it.

Neither the registry nor the abstract names a trial number. If this is a trial report, that itself is worth knowing.

3 · Its place in the literature

Who cites it

4 citing papers in PubMed.

  1. Review
  2. Literature review and DELPHI consensus on follow-up and retreatment of intracranial aneurysms with intrasaccular devices.Interventional neuroradiology : journal of peritherapeutic neuroradiology, surgical procedures and related neurosciences · 2025
    Article
  3. Review
  4. Review
4 · The record

Corrections and comments

PubMed lists nothing against this paper. Absence here is not a guarantee, only a check that was made.

5 · Who and what money

Authors and funding

41 authors.

Johanna M OspelDepartments of Diagnostic Imaging and Clinical Neurosciences, Foothills Medical Centre, University of Calgary, 1403 29th St. NW, T2N2T9, Calgary, AB, Canada. johannaospel@gmail.com.
Mahmood MirzaCerenovus, Galway, Ireland.
Frédéric ClarençonDepartment of Neuroradiology, Pitié-Salpêtrière Hospital, Sorbonne University, Paris, France.
Adnan SiddiquiDepartment of Neurosurgery, University of New York at Buffalo, Buffalo, NY, USA.
Karen DoyleDepartment of Physiology and CURAM-SFI Research Centre for Medical Devices, University of Galway, Galway, Ireland.
Arturo ConsoliService de Neuroradiologie Diagnostique et Thérapeutique, Hôpital Foch, Suresnes, France.
Maxim MokinDepartment of Neurosurgery and Brain Repair, University of South Florida, Tampa, FL, USA.
Teresa UllbergDepartments of Neurology and Diagnostic Imaging, Skåne University Hospital, and Department of clinical sciences, Neurology, Lund University, Lund, Sweden.
Osama ZaidatNeuroscience and Stroke Center, Mercy Health Bon Secours St Vincent Hospital, Toledo, OH, USA.
Romain BourcierDepartment of Diagnostic and Therapeutic Neuroradiology, University Hospital of Nantes, L'institut du thorax, Nantes, Pays de la Loire, France.
Zsolt KulcsarDepartment of Neuroradiology, University Hospital of Zurich, Zurich, Switzerland.
Matthew J GounisNew England Center for Stroke Research, Department of Radiology, University of Massachusetts Chan Medical School, Worcester, USA.
David S LiebeskindUCLA Stroke Center and Department of Neurology, University of California, Los Angeles, USA.
Jens FiehlerDepartment of Neuroradiology, University Hospital Hamburg-Eppendorf, Hamburg, Germany.
Ana Paula NarataDepartment of Interventional Neuroradiology, University Hospital of Southampton, Southampton, UK.
Marc RiboUnitat d'Ictus, Hospital Universitari Vall d'Hebron, Barcelona, Spain.
Tudor JovinCooper Neurological Institute, Cooper University Hospital, Camden, NJ, USA.
Nobuyuki SakaiDepartment of Neurosurgery, Kobe City Medical Center General Hospital, Kobe, Japan.
Ansaar RaiNeuroradiology Department, Rockefeller Neuroscience Institute, West Virginia University, Morgantown, USA.
Ray McCarthyResearch and Development, Cerenovus, Galway, Ireland.
Franziska DornDepartment of Neuroradiology, University Hospital of Bonn, Bonn, Germany.
Tommy AnderssonDepartment of Neuroradiology, Karolinska University Hospital and Clinical Neuroscience, Karolinska Intitutet, Stockholm, Sweden.
Charles B L M MajoieDepartment of Radiology and Nuclear Medicine, Amsterdam University Medical Centers, location University of Amsterdam, Amsterdam, The Netherlands.
Ricardo HanelBaptist neurological institute, Baptist Health, Jacksonville, FL, USA.
Ashutosh JadhavDepartment of Neurosurgery, Barrow Neurological Institute, Phoenix, AZ, USA.
Christian RiedelDepartment of Neuroradiology, University Hospital Göttingen, Georg-August-University, Göttingen, Germany.
Angel ChamorroHospital Clinic of Barcelona and Institut d'Investigaçions Biomèdicas August Pi Sunyer (IDIBAPS), University of Barcelona, Barcelona, Spain.
Waleed BrinjikjiDepartment of Radiology and Neurosurgery, Mayo Clinic Rochester, Rochester, MN, USA.
Vincent CostalatNeuroradiology department, University Hospital Güi-de-Chauliac, CHU de Montpellier, Montpellier, France.
Simon F DeMeyerLaboratory For Thrombosis Research, KU Leuven Campus Kulak Kortrijk, Kortrijk, Belgium.
Raul G NogueiraDepartment of Neurology, University of Pittsburgh Medical Centre, Pittsburgh, USA.
Christophe CognardDepartment of diagnostic and therapeutic Neuroradiology, University Hospital of Toulouse, Toulouse, France.
Joan MontanerNeurovascular Research Laboratory, Vall d'Hebron Institute of Research (VHIR) Barcelona, Barcelona, Spain.
Thomas W LeungDepartment of Medicine and Therapeutics, The Prince of Wales Hospital, The Chinese University of Hong Kong, Hong Kong, China.
Carlos MolinaStroke Center Vall d'Hebron Hospital, Barcelona, Spain.
Heleen van BeusekomDepartment of Cardiology, Erasmus MC University Medical Centre, Rotterdam, The Netherlands.
Antoni DavalosDepartment of Neuroscience, University Autònoma de Barcelona, Barcelona, Spain.
John WeiselDepartment of Cell and Developmental Biology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, USA.
Rene ChapotDepartment of Neuroradiology, Alfried Krupp Krankenhaus Ruttenscheid, Essen, Germany.
Markus MöhlenbruchDepartment of Interventional Neuroradiology, Heidelberg University Hospital, Heidelberg, Germany.
Patrick BrouwerHead World Wide Medical Affairs, Cerenovus, Galway, Ireland.

Funding

Cerenovus not applicable (Cerenovus funded the transportation and accomodation for the CLOTS 7.0 panelists)
6 · The paper itself

Abstract

backgroundPredicting a challenging clot when performing mechanical thrombectomy in acute stroke can be difficult. One reason for this difficulty is a lack of agreement on how to precisely define these clots. We explored the opinions of stroke thrombectomy and clot research experts regarding challenging clots, defined as difficult to recanalize clots by endovascular approaches, and clot/patient features that may be indicative of such clots.

methodsA modified DELPHI technique was used before and during the CLOTS 7.0 Summit, which included experts in thrombectomy and clot research from different specialties. The first round included open-ended questions and the second and final rounds each consisted of 30 closed-ended questions, 29 on various clinical and clot features, and 1 on number of passes before switching techniques. Consensus was defined as agreement ≥ 50%. Features with consensus and rated ≥ 3 out of 4 on the certainty scale were included in the definition of a challenging clot.

resultsThree DELPHI rounds were performed. Panelists achieved consensus on 16/30 questions, of which 8 were rated 3 or 4 on the certainty scale, namely white-colored clots (mean certainty score 3.1), calcified clots under histology (3.7) and imaging (3.7), stiff clots (3.0), sticky/adherent clots (3.1), hard clots (3.1), difficult to pass clots (3.1) and clots that are resistant to pulling (3.0). Most panelists considered switching endovascular treatment (EVT) techniques after 2-3 unsuccessful attempts.

conclusionThis DELPHI consensus identified 8 distinct features of a challenging clot. The varying degree of certainty amongst the panelists emphasizes the need for more pragmatic studies to enable accurate a priori identification of such occlusions prior to EVT.

Indexed as

Brain IschemiaEndovascular ProceduresStrokeThrombosisConsensus Statements as TopicDelphi TechniqueHumansThrombectomyTreatment OutcomeAcute ischemic strokeIntracranial vessel occlusionNeurovascular diseaseThrombectomyThrombus

Identifiers

PMID37284876

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Read under generation 80e0d062 · epoch 390. Bibliography from PubMed, PubMed Central and OpenAlex; grants from NIH RePORTER; trial links from ClinicalTrials.gov; estimates, votes and beliefs from the OpenQuestion graph.