title: Risk of aneurysm recurrence in patients with clipped cerebral aneurysms: results of long-term follow-up angiography.
abstract: OBJECTIVE
  With many patients living long after microsurgical aneurysm clipping for subarachnoid hemorrhage (SAH) and with the evolution of intravascular procedures as less invasive alternatives, knowledge of the long-term results of clipping is becoming important.
  
  
  METHODS
  Of 412 patients who underwent clipping of ruptured or unruptured cerebral aneurysms at our institution between 1976 and 1994 and who survived >3 years after surgery, 225 patients who were in good general condition and younger than 80 years were offered follow-up angiography to detect newly formed aneurysms. Of the 225, 80 patients (35.6%) agreed to undergo angiography. In addition, 32 patients underwent angiography for new medical indications other than SAH. Therefore, 112 patients underwent angiography, representing a total of 140 clipped aneurysms.
  
  
  RESULTS
  The mean interval from surgery was 9.3 years for all patients and 9.0 years for the clipped aneurysms (range 3 to 21 years). Four aneurysm regrowths were detected of the 140 (2.9%) clipped aneurysms, representing 3 of 125 completely clipped aneurysms, 1 of 14 incompletely clipped aneurysms, and 0 of 1 aneurysm not studied with postoperative angiography. De novo aneurysms were detected in 9 of 112 (8.0%) patients. The annual rate of de novo aneurysm formation was 0.89%.
  
  
  CONCLUSIONS
  This study shows that the annual rate of de novo aneurysm formation is relatively high (0.89%) and that the cumulative risk becomes significant after 9 years. In consideration of the fatality rate of SAH, follow-up angiography may be indicated for patients with clipped aneurysms 9 to 10 years after surgery.
authors.affiliation: Department of Neurosurgery, Aizu Chuou Hospital, Aizuwakamatsu, Japan. haku2111@akina.ne.jp
authors.forename: K
authors.initials: K
authors.lastname: Tsutsumi
authors.forename: K
authors.initials: K
authors.lastname: Ueki
authors.forename: A
authors.initials: A
authors.lastname: Morita
authors.forename: M
authors.initials: M
authors.lastname: Usui
authors.forename: T
authors.initials: T
authors.lastname: Kirino
mesh_terms: D015901:Angiography, Digital Subtraction; D002533:Cerebral Angiography; D015897:Comorbidity; D018450:Disease Progression; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D002532:Intracranial Aneurysm / Q000000981:diagnostic imaging* / Q000453:epidemiology* / Q000601:surgery; D007564:Japan / Q000453:epidemiology; D008297:Male; D008866:Microsurgery / Q000706:statistics & numerical data; D008875:Middle Aged; D019635:Neurosurgical Procedures / Q000706:statistics & numerical data; D012008:Recurrence; D012086:Reoperation / Q000706:statistics & numerical data; D018570:Risk Assessment; D013345:Subarachnoid Hemorrhage / Q000175:diagnosis / Q000453:epidemiology; D013525:Surgical Instruments / Q000706:statistics & numerical data; D015996:Survival Rate; D013995:Time; D014656:Vascular Surgical Procedures / Q000295:instrumentation