title: Risk factors for coil protrusion into the parent artery and associated thrombo-embolic events following unruptured cerebral aneurysm embolization.
abstract: OBJECTIVE
  Advances in vascular reconstruction devices and coil technologies have made coil embolization a popular and effective strategy for treatment of relatively wide-neck cerebral aneurysms. However, coil protrusion occurs occasionally, and little is known about the frequency, the risk factors and the risk of thrombo-embolic complications.
  
  
  METHODS
  We assessed the frequency and the risk factors for coil protrusion in 330 unruptured aneurysm embolization cases, and examined the occurrence of cerebral infarction by diffusion-weighted magnetic resonance imaging (DW-MRI).
  
  
  RESULTS
  Forty-four instances of coil protrusion were encountered during coil embolization (13.3% of cases), but incidence was reduced to 33 (10% of cases) by balloon press or insertion of the next coil. Coil protrusion occurred more frequently during the last phase of the procedure, and both a wide neck (large fundus to neck ratio) (OR = 1.84, P = 0.03) and an inadequately stable neck frame (OR = 5.49, P = 0.0007) increased protrusion risk. Coil protrusions did not increase the incidence of high-intensity lesions (infarcts) on DW-MRI (33.3% vs 29% of cases with no coil protrusion). However, longer operation time did increase infarct risk (P = 0.0003). Thus, tail or loop type coil protrusion did not increase the risk of thrombo-embolic complications, if adequate blood flow was maintained.
  
  
  CONCLUSIONS
  Coil protrusion tended to occur more frequently in cases of wide-neck aneurysms with loose neck framing. Moderate and less coil protrusion carries no additional thrombo-embolic risk, if blood flow is maintained, which can be aided by additional post-operative antiplatelet therapy.
authors.affiliation: Department of Endovascular Neurosurgery, Stroke Center, International Medical Center, Saitama Medical University, Japan hideaki@saitama-med.ac.jp.
authors.forename: Hideaki
authors.initials: H
authors.lastname: Ishihara
authors.affiliation: Department of Endovascular Neurosurgery, Stroke Center, International Medical Center, Saitama Medical University, Japan.
authors.forename: Shoichiro
authors.initials: S
authors.lastname: Ishihara
authors.affiliation: Department of Endovascular Neurosurgery, Stroke Center, International Medical Center, Saitama Medical University, Japan.
authors.forename: Jun
authors.initials: J
authors.lastname: Niimi
authors.affiliation: Department of Endovascular Neurosurgery, Stroke Center, International Medical Center, Saitama Medical University, Japan.
authors.forename: Hiroaki
authors.initials: H
authors.lastname: Neki
authors.affiliation: Department of Endovascular Neurosurgery, Stroke Center, International Medical Center, Saitama Medical University, Japan.
authors.forename: Yoshiaki
authors.initials: Y
authors.lastname: Kakehi
authors.affiliation: Department of Endovascular Neurosurgery, Stroke Center, International Medical Center, Saitama Medical University, Japan.
authors.forename: Nahoko
authors.initials: N
authors.lastname: Uemiya
authors.affiliation: Department of Endovascular Neurosurgery, Stroke Center, International Medical Center, Saitama Medical University, Japan.
authors.forename: Shinya
authors.initials: S
authors.lastname: Kohyama
authors.affiliation: Department of Endovascular Neurosurgery, Stroke Center, International Medical Center, Saitama Medical University, Japan.
authors.forename: Fumitaka
authors.initials: F
authors.lastname: Yamane
mesh_terms: D021721:Balloon Occlusion; D001807:Blood Vessel Prosthesis / Q000009:adverse effects*; D002533:Cerebral Angiography; D002536:Cerebral Arteries / Q000000981:diagnostic imaging / Q000293:injuries*; D002544:Cerebral Infarction / Q000000981:diagnostic imaging / Q000209:etiology; D038524:Diffusion Magnetic Resonance Imaging; D004621:Embolization, Therapeutic / Q000379:methods*; D005260:Female; D006801:Humans; D021621:Imaging, Three-Dimensional; D002532:Intracranial Aneurysm / Q000000981:diagnostic imaging / Q000628:therapy*; D008297:Male; D008875:Middle Aged; D010975:Platelet Aggregation Inhibitors / Q000627:therapeutic use; D011183:Postoperative Complications / Q000453:epidemiology*; D012189:Retrospective Studies; D012307:Risk Factors; D013923:Thromboembolism / Q000188:drug therapy / Q000453:epidemiology* / Q000209:etiology
chemical_list: D010975:Platelet Aggregation Inhibitors
keywords: Coil protrusion; cerebral aneurysm; thrombo-embolic complication