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Original research
Tourniquet parent artery occlusion after flow diversion
  1. Visish M Srinivasan1,
  2. Maxim Mokin2,
  3. Edward A M Duckworth3,
  4. Stephen Chen4,
  5. Ajit Puri5,
  6. Peter Kan1
  1. 1Department of Neurosurgery, Baylor College of Medicine, Houston, Texas, USA
  2. 2Department of Neurosurgery, University of South Florida, Tampa, Florida, USA
  3. 3Northwest Neurosurgical Associates, Boise, Idaho, USA
  4. 4Department of Radiology, Baylor College of Medicine, Houston, Texas, USA
  5. 5Department of Radiology, University of Massachusetts Medical School, Worcester, Massachusetts, USA
  1. Correspondence to Dr Peter Kan, Department of Neurosurgery, Baylor College of Medicine, Houston, TX 77030, USA; Peter.kan{at}


Background The Pipeline Embolization Device (PED) is increasingly used for both on- and off-label purposes for treatment of intracranial aneurysms. The device gradually slows flow of blood into the aneurysm, but the high metal coverage of PED promotes endothelialization of the device. Occasionally, this leads to in-stent stenosis that is clinically well tolerated. We present a multi-institutional Pipeline series that includes three cases of gradual asymptomatic occlusion within the PED and parent vessel.

Methods Institutional databases at each participating center were searched for patients treated with the PED. Patients with at least 50% stenosis or occlusion were selected and all relevant clinical and radiographic data were reviewed.

Results A total of 326 cases performed by five neurointerventionalists across four institutions were reviewed. Among these there were three cases of complete occlusion and two cases of stenosis of more than 50%, for an occlusion rate of 0.9%. All patients were clinically asymptomatic.

Conclusions A gradual tourniquet-like occlusion can occur following placement of the PED, leading to vessel occlusion. This has been clinically well tolerated by patients in our series due to the formation of pial collaterals as the stenosis progresses, likely due to ischemic preconditioning. Small parent vessel, pre-existing stenosis, fusiform pathology, overlapping devices, and suboptimal antiplatelet therapy seem to be predisposing factors. Further experience and follow-up will allow us to characterize the risk factors and optimize post-procedural therapy for these patients.

  • Flow Diverter
  • Aneurysm
  • Vessel Wall
  • Complication

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  • Contributors PK: conception and design. VMS, MM, EAMD, AP, SC: acquisition of data and analysis and interpretation of data. All authors drafted the article, critically revised it and reviewed the submitted version of the manuscript. VMS: approved the final version of the manuscript on behalf of all the authors. PK: study supervision.

  • Competing interests PK is a consultant for Stryker and Medtronic. PK and VMS receive grant/research support from Microvention. AP has received grant/research support from and serves as a consultant to Codman, Covidien, and Stryker Neurovascular.

  • Ethics approval IRB at each institution.

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

  • Data sharing statement Technical summary and further information regarding our research are available from the corresponding author at the Baylor College of Medicine. Any transmission of these data must be approved by the Baylor College of Medicine.