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Original research
How to perform intra-aneurysmal coil embolization after Pipeline deployment: a study from a hemodynamic viewpoint
  1. Mingqi Zhang1,
  2. Zhongbin Tian2,
  3. Yisen Zhang1,
  4. Ying Zhang1,
  5. Kun Wang1,
  6. Xiaochang Leng3,
  7. Xinjian Yang1,
  8. Jianping Xiang3,
  9. Jian Liu1
  1. 1Department of Interventional Neuroradiology, Beijing Neurosurgical Institute and Beijing Tiantan Hospital, Capital Medical University, Beijing, China
  2. 2Department of Neurosurgery, Zhujiang Hospital, Southern Medical University, Guangzhou, Guangdong, China
  3. 3ArteryFlow Technology, Hangzhou, China
  1. Correspondence to Dr Jian Liu, Department of Interventional Neuroradiology, Beijing Neurosurgical Institute and Beijing Tiantan Hospital, Capital Medical University, Beijing 100070, China; jianliu_ns{at}; Dr Jianping Xiang; jianping.xiang{at}


Background Pipeline embolization device (PED) deployment combined with coil therapy for large complex intracranial aneurysms is effective and considered superior to PED deployment alone. However, the optimal strategy for use of coils remains unclear. We used patient-specific aneurysm models and finite element analysis to determine the ideal packing density of coils after PED placement.

Methods Finite element analysis was used to provide a higher-fidelity model for accurate post-treatment computational fluid dynamics analysis to simulate the real therapeutic process of PED and all coils. We then calculated and analyzed the reduction ratio of velocity to identify the hemodynamic change during PED deployment and each coil embolization.

Results Sixteen consecutive patients underwent PED plus coil procedures to treat internal carotid artery intracranial aneurysms. After PED deployment, the intra-aneurysmal flow velocity significantly decreased (15.3 vs 10.0 cm/s; p<0.001). When the first coil was inserted, the flow velocity in the aneurysm further decreased and the reduction was significant (10.0 vs 5.3 cm/s; p<0.001). Analysis of covariance showed that the effect of the reduction ratio of velocity of the second coil was significantly lower than that of the first coil (p<0.001)—that is, when the packing density increased to 7.06%, the addition of coils produced no further hemodynamic effect.

Conclusion Adjunct coiling could improve the post-PED hemodynamic environment in treated intracranial aneurysms. However, dense packing is not necessary because the intra-aneurysmal hemodynamics tend to stabilize as the packing density reaches an average of 7.06% or after insertion of the second coil.

  • aneurysm
  • coil
  • flow diverter

Data availability statement

Data are available upon reasonable request. Not applicable.

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Data availability statement

Data are available upon reasonable request. Not applicable.

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  • Contributors Study concept and design: JL, MZ, XY. Acquisition of data and technique support: MZ, ZT, XL, XY, JX. Analysis and interpretation of data: YZ, KW, YZ. Drafting or revising the manuscript: MZ, JL, XL. Final approval of the version to be published: JL, JX. Agreement to be accountable for all aspects of the work: MZ. Responsible for the overall content: JL.

  • Funding This work was supported by Beijing Municipal Administration of Hospitals Incubating Program (PX2022022), Beijing Tiantan Hospitals Authority Youth Programme (code: QML20190503), and National Natural Science Foundation of China (grant numbers: 81801156, 82072036, 81901178 and 81801158).

  • 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.