European Radiology

, Volume 29, Issue 1, pp 77–84 | Cite as

Detection of in-stent protrusion (ISP) by intravascular ultrasound during carotid stenting: Usefulness of stent-in-stent placement for ISP

  • T. OkazakiEmail author
  • S. Sakamoto
  • K. Shinagawa
  • N. Ichinose
  • D. Ishii
  • T. Matsushige
  • Y. Kiura
  • K. Kurisu



As in-stent protrusion (ISP) during carotid artery stenting (CAS) may cause postoperative embolism, ISP detection is important. Intravascular ultrasound examination (IVUS) is useful for ISP detection because the blood vessel cross-section can be drawn as a tomogram from the lumen. Our objective was to clarify the occurrence of ISP during CAS using IVUS and relevant factors, and to report the usefulness of stent-in-stent placement when treating ISP.


In 142 consecutive patients (128 men, average age 71.7 years; 69 symptomatic) who underwent CAS using dual protection and the blood aspiration method, and subsequent IVUS after stent placement were included. The outcome of CAS, and the occurrence rate of ISP and related factors (plaque characteristics, stent design, intraoperative debris capture rate and postoperative diffusion-weighted imaging (DWI) positive rate) were examined.


All CAS procedures were successful and no major adverse events (MAEs) were observed at 30 days. ISP was found in 12% (17/142), and stent-in-stent placement was performed in all cases. Vulnerable plaques were observed in 12 of 17 ISP cases (71%). A closed stent was used in 13 of 17 ISP cases (71%). The intraoperative debris capture rate was 100%, and no neurological symptoms were observed in any patients. A significant increase in ISP susceptibility was related to vulnerable plaques and the intraoperative debris capture rate.


Vulnerable plaques and debris capture were significantly correlated with ISP occurrence. In all ISP cases, stent-in-stent placement was performed and good results were obtained.

Key Points

• ISP detection during CAS using IVUS is important.

• ISP-positive patients were correlated with NASCET ≥ 80%, vulnerable plaques and stent length.

• Adequate additional treatment of stent in stenting under reliable protection against ISP-positive patients achieved low perioperative complications.


Carotid stenosis Intravascular ultrasound Stents 





Carotid artery stenting


Close-cell design stent


Common carotid artery


Carotid endarterectomy


Carotid Revascularization Endarterectomy vs. Stenting Trial


Digital subtraction angiography


Diffusion-weighted imaging


External carotid artery


High-intensity signal


Internal carotid artery


In-stent protrusion


Intravascular ultrasound


Major adverse events


North American Symptomatic Carotid Endarterectomy Trial


Open-cell design stent


Optical coherence tomography


Optical frequency domain imaging


Percutaneous transluminal angioplasty


Transient ischaemic attack



The authors state that this work has not received any funding.

Compliance with ethical standards


The scientific guarantor of this publication is Prof. Kaoru Kurisu.

Conflict of interest

The authors of this manuscript declare no relationships with any companies whose products or services may be related to the subject matter of the article.

Statistics and biometry

No complex statistical methods were necessary for this paper.

Informed consent

Written informed consent was waived by the Institutional Review Board.

Ethical approval

Institutional Review Board approval was obtained.


• Retrospective

• Case-control study

• Performed at one institution


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Copyright information

© European Society of Radiology 2018

Authors and Affiliations

  1. 1.Department of Neurosurgery, Graduate School of Biomedical and Health SciencesHiroshima UniversityHiroshimaJapan

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