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The occurrence of neointimal hyperplasia after flow-diverter implantation is associated with cardiovascular risks factors and the stent design
  1. Jildaz Caroff1,
  2. Marta Iacobucci1,
  3. Aymeric Rouchaud2,3,
  4. Cristian Mihalea1,
  5. Fernando Mota de Carvalho4,
  6. Victor Erwin D Jocson5,
  7. Vanessa Chalumeau1,
  8. Valerio Da Ros6,
  9. Robert M King7,
  10. Rose Arslanian7,
  11. Léon Ikka1,
  12. Nidhal Ben Achour1,
  13. Jacques Moret1,
  14. Laurent Spelle1
  1. 1 Department of Interventional Neuroradiology, NEURI Centre, Bicêtre Hospital, Le Kremlin-Bicêtre, France
  2. 2 Department of Radiology, Limoges University Hospital, Limoges, France
  3. 3 CNRS, XLIM, UMR 7252, University of Limoges, Limoges, France
  4. 4 Department of Radiology, Neuroradiology Section, Hospital Antonio Prudente, Fortaleza, Brazil
  5. 5 The Medical City, Makati Medical Centre, Asian Hospital and Medical Centre, Manila, Philippines
  6. 6 Dipartimento di Diagnostica per Immagini e Radiologia Interventistica, Policlinico Universitario di Roma ’Tor Vergata', Rome, Italy
  7. 7 New England Center for Stroke Research, Department of Radiology, University of Massachusetts Medical School, Worcester, Massachusetts, USA
  1. Correspondence to Dr Jildaz Caroff, Department of Interventional Neuroradiology, NEURI Center, Bicêtre Hospital, Le Kremlin-Bicêtre 94270, France; jildaz.caroff{at}


Background Neo-intimal hyperplasia (NIH) is frequently observed after flow-diverter stent (FDS) implantation. Although mostly asymptomatic, this vascular response can sometimes lead to delayed ischemic strokes. This study intended to evaluate the factors potentially influencing the rates of NIH following FDS treatment.

Material and Methods All aneurysm treatments performed with a Pipeline embolization device (PED) or a SILK stent from May 2011 to May 2015 were collected in a prospectively maintained database. Patient demographics, clinical, and angiographic outcomes including both digital subtraction angiography and C-arm cone-beam CT were registered. Two blind reviewers rated the presence of NIH on a binary scale (present/absent).

Results From 148 patients, 63 datasets were available for analysis. Inter-reader agreement was excellent (Kappa=0.88). NIH was positively correlated with smoking, dyslipidemia, and high blood pressure, but not with aneurysm characteristics. At early follow-up (<12 months), NIH was more frequently associated with the use of the SILK stent (68%) rather than the PED (38%): P<0.02. At long-term follow-up, the NIH rate in the total population dropped from 55% to 26% with no more significant difference between the two stents. The complete occlusion rate as seen in early follow-up was higher in the SILK group with 76% vs 65% but without statistical significance (P=0.4).

Conclusion NIH is a dual-vessel reaction after FDS implant. When planning a treatment in locations at risk of ischemic complications if severe NIH would occur, then the stent design should be considered. However, minimal NIH might also be needed as it is involved in aneurysm healing. Before treatment patients should be recommended best medical management of their cardiovascular risks factors to prevent an excessive NIH reaction.

  • aneurysm
  • angiography
  • flow diverter
  • stenosis

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  • Contributors JC: designed the study, analyzed and interpreted the data, drafted the manuscript, and approved the final manuscript. All authors: data set creation and approved the final manuscript

  • Funding Partially supported by research grants from the Fulbright Program, the Philippe Foundation, and the French Society of Radiology (Bourse de Recherche SFR-CERF).

  • Competing interests JC: Educational scholarships from Medtronic Neurovascular and Microvention/Terumo. JM: consultant for Medtronic, Microvention, Stryker, and Balt. LS: consultant for Stryker, MicroVention, Medtronic, Balt.

  • Patient consent Obtained.

  • Ethics approval CNIL Paris.

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

  • Data sharing statement Data available upon request to the corresponding author.