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Long-term safety and efficacy of distal aneurysm treatment with flow diversion in the M2 segment of the middle cerebral artery and beyond
  1. Petra Cimflova1,2,
  2. Enes Özlük3,
  3. Bora Korkmazer4,
  4. Ramiz Ahmadov5,
  5. Elif Akpek6,
  6. Osman Kizilkilic4,
  7. Civan Islak4,
  8. Naci Kocer4
  1. 1Department of Medical Imaging, St. Anne’s University Hospital Brno and Faculty of Medicine, Masaryk University Brno, Brno, Czech Republic
  2. 2Faculty of Medicine in Hradec Kralove, Charles University, Hradec Kralove, Czech Republic
  3. 3Department of Radiology, Acibadem Atakent Hospital, Istanbul, Turkey
  4. 4Department of Neuroradiology, Cerrahpasa Medical Faculty, Istanbul University-Cerrahpasa, Istanbul, Turkey
  5. 5Department of Neurosurgery, Acibadem Atakent Hospital, Istanbul, Turkey
  6. 6Department of Anaestesiology and Reanimation, Acibadem Universitesi Medical Faculty, Istanbul, Turkey
  1. Correspondence to Professor Naci Kocer, Department of Neuroradiology, Istanbul University-Cerrahpasa Cerrahpasa Faculty of Medicine, Istanbul 34098, Turkey; nkocer{at}


Background Indications for flow diversion stent (FDS) treatment are expanding. However, there is still a lack of evidence for the long-term outcome in distally located aneurysms in the M2 segment of the middle cerebral artery (MCA) and beyond.

Methods Consecutive subjects (from June 2013 to August 2020) with MCA aneurysms in the M2 segment or beyond treated with FDS were reviewed retrospectively. The primary endpoints for clinical safety were the absence of mortality, stroke event, re-rupture of the aneurysm, and worsening of clinical symptoms. The primary endpoint for treatment efficacy was complete/near-complete occlusion at follow-up after 12 months.

Results 23 patients were identified: 7 aneurysms were located in the M2 segment of the MCA, 4 in the M2-M3 bifurcation, 2 in M3, 3 in M3-4 branching, and 2 in M4; 5 aneurysms were located in M2 with extension into the M1-M2 bifurcation. 13 aneurysms were of fusiform morphology, 8 sacculofusiform, and 2 saccular. 16 aneurysms were of highly suspected dissecting etiology. The median diameter of the parent vessel was 2.1 mm proximally and 2 mm distally. The median time of the follow-up was 30 months (range 16 months to 6 years). Complete/near complete occlusion was observed in 14/20 patients (70%) and one stable remodeling (5%) was seen at 12 months. 22 patients (95.6%) had an excellent clinical outcome (mRS 0–1) at 6 months. Technical challenges associated with the deployment of FDS occurred in 8.7% of cases. Severe complications, intraparenchymal hemorrhage and re-rupture of the aneurysm occurred in 2 patients (8.7%).

Conclusion Flow diversion of distally located aneurysms is technically feasible with low morbidity and mortality.

  • aneurysm
  • flow diverter
  • dissection
  • intervention
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  • Contributors PC: Data analysis, visualization, drafting of the manuscript. EÖ: Data curation, visualization, critical revision of the manuscript. NK: Conceptualization, drafting and critical revision of the manuscript. Remaining authors: Data curation, critical revision of the manuscript.

  • Funding The authors have not declared a specific grant for this research from any funding agency in the public, commercial or not-for-profit sectors.

  • Competing interests NK is a consultant for MicroVention (consultant and proctorship agreement) outside of this work.

  • Patient consent for publication Obtained.

  • Provenance and peer review Not commissioned; externally peer reviewed.

  • Data availability statement Data are available upon reasonable request. Deidentified data and statistical analyses are available upon reasonable request from PC (ORCID ID: 0000-0001-8058-383X) and NK (ORCID ID: 0000-0003-0884-6492).

  • Supplemental material This content has been supplied by the author(s). It has not been vetted by BMJ Publishing Group Limited (BMJ) and may not have been peer-reviewed. Any opinions or recommendations discussed are solely those of the author(s) and are not endorsed by BMJ. BMJ disclaims all liability and responsibility arising from any reliance placed on the content. Where the content includes any translated material, BMJ does not warrant the accuracy and reliability of the translations (including but not limited to local regulations, clinical guidelines, terminology, drug names and drug dosages), and is not responsible for any error and/or omissions arising from translation and adaptation or otherwise.

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