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Original research
Transient in-stent stenosis at mid-term angiographic follow-up in patients treated with SILK flow diverter stents: incidence, clinical significance and long-term follow-up
  1. Fahad Essbaiheen1,2,
  2. Hanan AlQahtani1,
  3. Taleb Mohamed Almansoori3,
  4. Elena Adela Cora1,
  5. Satya Patro1,
  6. Vered Tsehmaister-Abitbul1,
  7. Brian Drake4,
  8. Howard Lesiuk4,
  9. Stephanos Nikolaos Finitsis1,
  10. Daniela Iancu1
  1. 1 Division of Interventional Neuroradiology, Department of Diagnostic Imaging, The Ottawa Hospital, Ottawa, Ontario, Canada
  2. 2 Department of Medical Imaging, King Saud University, Riyadh, Riyadh Province, Saudi Arabia
  3. 3 Radiology Department, College of Medicine and Health Sciences, Al Ain, United Arab Emirates
  4. 4 Department of Neurosurgery, The Ottawa Hospital, Ottawa, Ontario, Canada
  1. Correspondence to Dr. Daniela Iancu, Diagnostic Imaging, The Ottawa Hospital,Ottawa, Ontario K1Y4E9, Canada; diancu{at}


Background Little is known about in-stent stenosis (ISS) in patients with aneurysms treated with flow diverter (FD) stents. The reported incidence in the literature varies significantly.

Objective The aim of this study was to assess the incidence, severity, distribution, clinical significance, and possible predictors for ISS.

Methods Between July 2012 and June 2016 we retrospectively reviewed all patients treated with SILK FDs in our center. Only cases with short-term (4±2 months) and long-term (>1 year) follow-ups with digital subtraction angiograms were included. ISS was graded as mild (<25%), moderate (25–50%) or severe (>50%). The following predictors for ISS were assessed: gender, age, the presence of subarachnoid hemorrhage, aneurysm size, location, occlusion status, and post-stenting angioplasty.

Results Thirty-six patients met the inclusion criteria. At mid-term follow-up, ISS was observed in 16/36 patients (44%). Eleven patients (69%) had mild ISS, three (19%) moderate, and two (12%) severe ISS. ISS was diffuse in 11 patients (69%) and focal in five patients (31%). All patients were asymptomatic. Thirteen patients were maintained on dual antiplatelet therapy and three on aspirin alone. At long-term follow-up, complete ISS resolution was seen in 11 patients, improvement in three and worsening in two patients. No de novo ISS occurrence was observed. On univariate analysis there was no significant predictor for ISS.

Conclusions Transient ISS after FD deployment is a common asymptomatic finding on mid-term angiographic follow-up. Complete resolution or improvement at long-term follow-up is seen in most patients who are maintained on dual antiplatelet therapy.

  • flow diverter
  • stenosis
  • aneurysm
  • stent

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  • Contributors Study concept and design: FE and DI. Data collection and analysis: all authors. Literature review: FE and DI. Manuscript drafting: FE. Manuscript revision, editing, final approval and accountable for all aspects of the work: all authors.

  • 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.

  • Patient consent Not required.

  • Ethics approval Ottawa Health Science Network Research Ethics Board.

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

  • Data sharing statement Additional data can be acquired by contacting the corresponding author.