Long-term follow-up of in-stent stenosis after pipeline flow diversion treatment of intracranial aneurysms

Seby John, Mark D. Bain, Ferdinand K. Hui, M. Shazam Hussain, Thomas J. Masaryk, Peter A. Rasmussen, Gabor Toth

Research output: Contribution to journalArticlepeer-review

39 Scopus citations


BACKGROUND: There is scant information on in-stent stenosis after flow diversion treatment of intracranial aneurysms with the Pipeline Embolization Device (PED). OBJECTIVE: To assess the incidence, severity, nature, and clinical consequences of in-stent stenosis on angiographic follow-up after treatment with the PED. METHODS: A retrospective study of patients who underwent aneurysm treatment with the PED was conducted. In-stent stenosis was assessed on subsequent follow-up angiography. Intimal hyperplasia was defined as a uniform growth process beyond the limits of the metallic mesh at <25%. In-stent stenosis represented an area of parent vessel narrowing, most often focal, graded as mild (25%-50%), moderate (50%-75%), or severe (>75%). RESULTS: Between June 2011 and April 2015, 80 patients were treated with the PED. Angiographic follow-up was available for 51 patients (representing 76% of available or 64% of all patients). Mean follow-up was 12.5 months. In-stent stenosis was detected in 5 patients (9.8%) at a median of 6 months. Stenosis was mild in 4 of 5 (80%) and moderate in 1 of 5 (20%) patients. There were no cases of severe stenosis. No stenosis caused flow limitation, clinical symptoms, or required re-treatment. Additional follow-up angiography was available in 2 of 5 stenosis patients showing marked improvement. Sixteen patients (31%) had intimal hyperplasia, and 28 patients (55%) had no stenosis. Asymptomatic stent occlusion occurred in 2 patients (4%) related to medication noncompliance. CONCLUSION: Treatment with the PED was associated with a 9.8% rate of in-stent stenosis, detected on first angiographic follow-up, at a median of 6 months. None were symptomatic or required re-treatment, and they showed significant improvement on follow-up. ABBREVIATION: FD, flow diverter.

Original languageEnglish (US)
Pages (from-to)862-867
Number of pages6
Issue number6
StatePublished - Jun 1 2016
Externally publishedYes


  • Flow diverter
  • In-stent stenosis
  • Intracranial aneurysm
  • Pipeline

ASJC Scopus subject areas

  • Surgery
  • Clinical Neurology


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