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Original research
Pipeline embolization device diameter is an important factor determining the efficacy of flow diversion treatment of small intracranial saccular aneurysms
  1. Matthew James Kole1,
  2. Timothy Ryan Miller2,
  3. Gregory Cannarsa1,
  4. Aaron Wessell1,
  5. Salazar Jones1,
  6. Elizabeth Le1,
  7. Gaurav Jindal2,
  8. François Aldrich1,
  9. J Marc Simard1,
  10. Dheeraj Gandhi2
  1. 1 Department of Neurosurgery, University of Maryland Medical Center, Baltimore, Maryland, USA
  2. 2 Department of Radiology, University of Maryland, Baltimore, Maryland, USA
  1. Correspondence to Dr Timothy Ryan Miller, Radiology, University of Maryland, Baltimore MD 21201, USA; tmiller5{at}


Objective Flow diversion using the Pipeline embolization device (PED) has become a widely used treatment method for intracranial aneurysms. However, a subset of aneurysms will fail to occlude following treatment and the factors that influence the efficacy of flow diversion remain uncertain. As smaller diameter PEDs inherently have greater metal density than larger devices, we elected to investigate whether PED diameter influences treatment efficacy when using a single device. We also evaluated other factors that may influence treatment outcomes with PED.

Methods We retrospectively evaluated all patients treated for an intracranial saccular aneurysm at our institution with a single PED at least 12 months prior to the time of data collection. Patients treated with multiple devices, adjunctive coiling, traumatic and fusiform target aneurysms, as well as patients with inadequate imaging follow-up (<12 months) were excluded.

Results 158 aneurysms in 124 patients (128 treatments) met the inclusion criteria for our study. 123 aneurysms (80%) were occluded over an average follow-up of 26.6 months. Multivariable logistic regression showed that branch vessel incorporation into the target aneurysm sac (p<0.001, OR=0.15) was significantly associated with aneurysm persistence, while smaller PED diameter was significantly associated with aneurysm occlusion (p=0.008; OR=0.30).

Conclusions PED diameter significantly impacts outcomes when using a single device for the treatment of small anterior circulation intracranial saccular aneurysms, most likely due to the inherent greater metal density of smaller devices. This factor should be taken into account when planning endovascular aneurysm treatment with PED.

  • cerebral aneurysm
  • flow diverter

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  • Contributors MJK, TRM: substantial contributions to the study design, data acquisition, analysis, and interpretation of data; drafted and gave final approval for the manuscript; accountable for all aspects of the submitted manuscript. GC, AW, SJ, EL, GJ, FA, JMS: substantial contributions to the data acquisition and analysis; gave final approval for the manuscript; accountable for all aspects of the submitted manuscript. DG: substantial contributions to the study design and interpretation of data; gave final approval for the manuscript; accountable for all aspects of the submitted manuscript.

  • 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.

  • Ethics approval The protocol for this retrospective cohort study was approved by the University of Maryland, Baltimore Institutional Review Board (HP-00077364).

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

  • Patient consent for publication Not required.