title: Endovascular therapy of 500 small asymptomatic unruptured intracranial aneurysms.
abstract: OBJECTIVE
  Although the natural course of UIAs remains unclear, the risk of aneurysmal SAH due to small (<10 mm) asymptomatic UIAs is low. Endovascular therapy for UIAs has increased because of device development and the need for less invasive treatment. We report the results, safety, and efficacy of endovascular therapy of small asymptomatic UIAs.
  
  
  METHODS
  A total of 457 patients with 500 small asymptomatic UIAs (maximum diameter < 10 mm) underwent endosaccular coil embolization at Juntendo University Hospital and affiliated hospitals. We retrospectively evaluated the technical feasibility, immediate and short-to-midterm follow-up anatomic results, procedure-related complications, and clinical outcomes.
  
  
  RESULTS
  Endosaccular coil embolization was completed in 481 aneurysms (96.2%) and attempted in 19 (3.8%). Completed aneurysms were treated with the simple (39.5%), balloon-assisted (51.4%), and double-catheter (9.1%) techniques. Immediate angiographic outcomes were CO for 309 (64.2%) aneurysms, RN for 72 (15.0%), and RA for 100 (20.8%). Procedure-related complications occurred in 38 aneurysms (7.6%): 19 ischemic, 11 hemorrhagic, and 8 others. Permanent morbidity and mortality were 0.8% and 0.2%, respectively. Anatomic outcome of 427 aneurysms followed up for >6 months with conventional catheter or MR angiographies showed recanalization in 72 (16.9%) aneurysms, necessitating retreatment in 9.9% (mean, 31.4 months). No patients had aneurysmal SAH during the clinical follow-up period (mean, 34.7 months).
  
  
  CONCLUSIONS
  In this series, endovascular therapy of small asymptomatic UIAs was highly feasible with low morbidity and mortality rates.
authors.affiliation: Department of Neurosurgery, Juntendo University School of Medicine, Tokyo, Japan. ohishi@juntendo.ac.jp
authors.forename: H
authors.initials: H
authors.lastname: Oishi
authors.forename: M
authors.initials: M
authors.lastname: Yamamoto
authors.forename: T
authors.initials: T
authors.lastname: Shimizu
authors.forename: K
authors.initials: K
authors.lastname: Yoshida
authors.forename: H
authors.initials: H
authors.lastname: Arai
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D017542:Aneurysm, Ruptured; D015897:Comorbidity; D057510:Endovascular Procedures / Q000401:mortality*; D005260:Female; D006801:Humans; D002532:Intracranial Aneurysm / Q000401:mortality* / Q000601:surgery*; D007564:Japan / Q000453:epidemiology; D008297:Male; D008875:Middle Aged; D011183:Postoperative Complications / Q000401:mortality*; D015995:Prevalence; D018570:Risk Assessment; D012307:Risk Factors; D016019:Survival Analysis; D015996:Survival Rate; D016896:Treatment Outcome; D055815:Young Adult