Article Text

Download PDFPDF

Original research
Progressive thrombosis of unruptured aneurysms after coil embolization: analysis of 255 consecutive aneurysms
  1. Yusuke Funakoshi,
  2. Hirotoshi Imamura,
  3. Shoichi Tani,
  4. Hidemitsu Adachi,
  5. Ryu Fukumitsu,
  6. Tadashi Sunohara,
  7. Yoshihiro Omura,
  8. Yuichi Matsui,
  9. Natsuhi Sasaki,
  10. Tatsumaru Fukuda,
  11. Ryo Akiyama,
  12. Kazufumi Horiuchi,
  13. Shinji Kajiura,
  14. Masashi Shigeyasu,
  15. Nobuyuki Sakai
  1. Neurosurgery, Kobe City Medical Center General Hospital, Kobe, Japan
  1. Correspondence to Dr Yusuke Funakoshi, Neurosurgery, Kobe City Medical Center General Hospital, Kobe 650-0047, Japan; sf1wan0610{at}


Introduction We have observed that aneurysms treated by insufficient coil embolization and filled with contrast agent immediately after the procedure are often completely occluded at follow-up. However, there are limited studies showing progressive thrombosis of aneurysms after coil embolization. Herein, we describe our experience with coil embolization for aneurysms, and discuss the factors involved in progressive thrombosis.

Methods A total of 255 aneurysms treated by coil embolization in our institute between January 2011 and June 2017 and observed >6 months were included. ‘Progressive thrombosis’ indicated that aneurysms that were neck remnant (NR) or dome filling (DF) immediately after coil embolization changed to complete obliteration (CO) at the 6-month follow-up digital subtraction angiography. The factors involved in progressive thrombosis were assessed.

Results In all aneurysms (n=255), 24 (9.4%) were CO, 82 (32.2%) were NR, and 149 (58.4%) were DF immediately after the procedure. At 6-month digital subtraction angiography, 123 (48.2%) were CO, 95 (37.3%) were NR, and 37 (14.5%) were DF. Retreatment for major recanalization was performed in eight cases (3.1%). One hundred and three aneurysms showed progressive thrombosis. There were significant differences in aneurysm location (P=0.0002), aneurysm dome diameter (P=0.0015), aneurysm neck diameter (P=0.0068), volume embolization ratio (P=0.0054), and endovascular procedure with stent (P=0.0264) between the progressive thrombosis and no thrombosis groups.

Conclusions Progressive thrombosis can occur in aneurysms after coil embolization depending on aneurysm location and size, and stent use. Thus, the degree of coil embolization and combination with a stent should be adjusted depending on aneurysm type.

  • aneurysm
  • intervention

Statistics from

Request Permissions

If you wish to reuse any or all of this article please use the link below which will take you to the Copyright Clearance Center’s RightsLink service. You will be able to get a quick price and instant permission to reuse the content in many different ways.


  • Contributors All authors meet the ICMJE authorship criteria. YF designed this study and wrote the initial draft of the manuscript. All other authors critically reviewed the manuscript and assisted in the preparation of the manuscript. All authors approved the final version of the manuscript, and agree to be accountable for all aspects of the work in ensuring that questions related to the accuracy or integrity of any part of the work are appropriately investigated and resolved.

  • 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.

  • Patient consent for publication Not required.