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Original research
Results of watchful waiting of unruptured intracranial aneurysms in a Western patient population: a single-center cohort
  1. Mathilde Aubertin1,
  2. Clément Jourdaine1,
  3. Cédric Thépenier2,3,
  4. Marc-Antoine Labeyrie1,
  5. Vittorio Civelli1,
  6. Jean-Pierre Saint-Maurice1,
  7. Alexis Guédon1,4,
  8. Emmanuel Houdart1,4
  1. 1Department of Neuroradiology, AP-HP, Hôpital Lariboisière, Paris, France
  2. 2French Armed Forces Biomedical Research Institute (IRBA), Brétigny-sur-Orge, France
  3. 3Department of Experimental Neuropathology, Institut Pasteur, Paris, France
  4. 4School of Medicine, Université de Paris, F-75006 Paris, France
  1. Correspondence to Dr Mathilde Aubertin, Department of Neuroradiology, AP-HP, Paris 75184, France; aubertin.mathilde{at}


Background The natural history of unruptured intracranial aneurysms (UIAs) in Western populations is still debated, especially for those <7 mm. Reporting data of a large single-center cohort managed with watchful waiting is therefore interesting.

Methods From January 2011 to June 2019, 662 UIAs were followed up by yearly MR angiography. Morphologically stable UIAs were managed conservatively while unstable UIAs were offered treatment. The patients’ clinical and radiological data were analyzed retrospectively.

Results UIAs were ≤4 mm in 60%, 4.1–7.0 mm in 33%, and >7 mm in 7%. They were located on the anterior circulation in 90% of cases. The mean follow-up duration was 51.32 months for a total of 2831 aneurysm-years. During follow-up, 37 UIAs (5.5%) were treated because of an increase in size, and 8 UIAs were treated because of patient decision. Three aneurysms ruptured during follow-up for an annual risk of rupture of 0.1% (95% CI 0% to 0.24%). No risk factors for rupture were identified. The three ruptured cases made an excellent recovery. During follow-up, annual mortality from unrelated causes was 0.8% (95% CI 0.51% to 1.18%).

Conclusions This single-center cohort evaluated our watchful waiting policy applied in two-thirds of all incidental UIAs. Morphological change of UIAs during follow-up led to treatment in 5.5% of cases. With such a management paradigm, we found a low rupture rate in these selected UIAs and the mortality was unrelated to aneurysms.

  • aneurysm
  • subarachnoid
  • hemorrhage

Data availability statement

Data are available upon reasonable request.

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Data availability statement

Data are available upon reasonable request.

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  • Contributors Conception and design: MA, EH. Acquisition of data: MA, CJ, EH. Analysis and interpretation of data: MA, CJ, CT, AG, EH. Drafting the article: MA, AG, EH. Critical revision of the article: M-AL, VC, J-PS-M, AG. Review of submitted version of manuscript: MA, AG, EH. Approval of the final version of the manuscript on behalf of all authors: MA. Author acting as guarantor: MA.

  • 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 None declared.

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

  • 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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