Could late rebleeding overturn the superiority of cranial aneurysm coil embolization over clip ligation seen in the International Subarachnoid Aneurysm Trial?

J Neurosurg. 2008 Mar;108(3):437-42. doi: 10.3171/JNS/2008/108/3/0437.


Object: The present purpose is to define the sensitivity of the superiority of coil embolization observed in the International Subarachnoid Aneurysm Trial (ISAT) according to the rate of late rebleeding over a reasonable range, and to find the range of rebleeding rates for which it may be overturned. In the ISAT, coil embolization appears to be safer than clip ligation at 1 year, and clip occlusion has better long-term efficacy at preventing rebleeding. This leaves open the question of which is better in the longer term.

Methods: The authors calculate the life expectancy of patients following a subarachnoid hemorrhage (SAH) and compare the life expectancy of those who underwent coil embolization with those who underwent clip ligation in the ISAT cohort.

Results: The 1-year poor outcome rate following treatment climbs rapidly with advancing age. A consequence is that the absolute difference between the poor outcome rates after coil embolization and clip occlusion is lower in those < 50 years of age (3.3%) than it is for those > 50 years of age (10.1%). This difference may be enough to give clip application the advantage in the < 40-year-old group despite the small size of the difference in 1-year rebleeding rates thus far observed (0.152%).

Conclusions: When treating ruptured cerebral aneurysms, the advantage of coil embolization over clip ligation cannot be assumed for patients < 40 years old. In this age range the difference in the safety of the 2 procedures is small, and the better long-term protection from SAH afforded by clip placement may give this treatment an advantage in life expectancy for patients < 40 years of age.

Publication types

  • Randomized Controlled Trial
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Adult
  • Age Factors
  • Aged
  • Aged, 80 and over
  • Aneurysm, Ruptured / complications
  • Aneurysm, Ruptured / mortality
  • Aneurysm, Ruptured / therapy*
  • Angioplasty*
  • Embolization, Therapeutic / adverse effects
  • Embolization, Therapeutic / instrumentation
  • Embolization, Therapeutic / methods*
  • Female
  • Follow-Up Studies
  • Humans
  • Intracranial Aneurysm / complications
  • Intracranial Aneurysm / mortality
  • Intracranial Aneurysm / therapy*
  • Ligation
  • Male
  • Middle Aged
  • Recurrence
  • Subarachnoid Hemorrhage / etiology
  • Subarachnoid Hemorrhage / mortality
  • Subarachnoid Hemorrhage / therapy*
  • Survival Rate
  • Treatment Outcome