Introduction: Very little is known on the incidence of in-stent stenosis following Pipeline embolization device (PED) treatment of intracranial aneurysms. The objective of this study was to evaluate the incidence and clinical significance through quantification of the degree of in stent stenosis at angiographic follow-up after PED placement. The secondary objective was to analyze literature reported rates of in stent stenosis following flow diverter treatment.
Methods: Clinical and radiological records from all patients undergoing PED treatment of intracranial aneurysms at a major US academic center from 2013 until 2017 were retrospectively reviewed. A modified version of the North American Symptomatic Carotid Endarterectomy (NASCET) criteria was used to quantify the degree of stenosis on most-recent post-procedural angiograms. A search of PubMED, MEDLINE, EMBASE and Web of Science electronic databases was furthermore conducted in accordance with PRISMA guidelines.
Results: Between March 2013 and July 2017, 168 patients (mean age=58.3 years, 30 men) harbouring 168 aneurysms underwent treatment with the Pipeline Embolization Device (Medtronic Inc, Dublin, Ireland) at our institution. In stent stenosis was detected in 12 patients (7.1%) at a median angiographic follow-up of 6 months. Mean percentage of stenosis was 39% (standard deviation 19%). Only one case was symptomatic. Aneurysm occlusion rates were comparable between the stenosis and non-stenosis cohorts (76.9% and 71.6%, respectively). No significant differences between either clopidogrel responder status, or subsequent post-procedural anti-platelet regimen were detected between the stenosis and non-stenosis cohorts. Following systematic review, 44 papers met the inclusion criteria. The mean literature-reported in stent stenosis rate was 6.34%
Conclusions: In stent stenosis following treatment of intracranial aneurysms remains a rare phenomenon. Further studies with longer follow-up durations are needed to ascertain the effect of anti-platelet regimens on the development of in stent stenosis.
Patient Care: This may serve to answer questions regarding efficacy of flow diverting stents, additionally in comparison to coronary stent.
Learning Objectives: By the conclusion of this session, participants should be able to:]
1) Understand the NASCET criteria for measuring stenosis
2) Appreciate the incidence of in stent stenosis following flow diversion for intracranial aneurysms