Long-term follow-up of unruptured intracranial aneurysms repaired in California

J Neurosurg. 2014 Jun;120(6):1349-57. doi: 10.3171/2014.3.JNS131159. Epub 2014 Apr 11.


Object: Using a database that enabled longitudinal follow-up, the authors assessed the long-term outcomes of unruptured cerebral aneurysms repaired by clipping or coiling.

Methods: An observational analysis of the California Office of Statewide Health Planning and Development (OSHPD) database, which follows patients longitudinally in time and through multiple hospitalizations, was performed for all patients initially treated for an unruptured cerebral aneurysm in the period from 1998 to 2005 and with follow-up data through 2009.

Results: Nine hundred forty-four cases (36.5%) were treated with endovascular coiling, 1565 cases (60.5%) were surgically clipped, and 76 cases were treated with both coiling and clipping. There was no significant difference in any demographic variable between the two treatment groups except for age (median: 55 years for the clipped group, 58 years for the coiled group, p < 0.001). Perioperative (30-day) mortality was 1.1% in patients with coiled aneurysms compared with 2.3% in those with clipped aneurysms (p = 0.048). The median follow-up was 7 years (range 4-12 years). At the last follow-up, 153 patients (16.2%) in the coiled group had died compared with 244 (15.6%) in the clipped group (p = 0.693). The adjusted hazard ratio for death at the long-term follow-up was 1.14 (95% CI 0.9-1.4, p = 0.282) for patients with endovascularly treated aneurysms. The incidence of intracranial hemorrhage was similar in the two treatment groups (5.9% clipped vs 4.8% coiled, p = 0.276). One hundred ninety-three patients (20.4%) with coiled aneurysms underwent additional hospitalizations for aneurysm repair procedures compared with only 136 patients (8.7%) with clipped aneurysms (p < 0.001). Cumulative hospital costs per patient for admissions involving aneurysm repair procedures were greater in the clipped group (median cost $98,260 vs $81,620, p < 0.001) through the follow-up.

Conclusions: For unruptured cerebral aneurysms, an observed perioperative survival advantage for endovascular coiling relative to that for surgical clipping was lost on long-term follow-up, according to data from an administrative database of patients who were not randomly allocated to treatment type. A cost advantage of endovascular treatment was maintained even though endovascularly treated patients were more likely to undergo subsequent hospitalizations for additional aneurysm repair procedures. Rates of aneurysm rupture following treatment were similar in the two groups.

Keywords: ISAT = International Subarachnoid Aneurysm Trial; ISUIA = International Study of Unruptured Intracranial Aneurysms; OSHPD = Office of Statewide Health Planning and Development; cerebral aneurysm; clipping; coiling; endovascular therapy; surgical treatment; vascular disorders.

Publication types

  • Comparative Study

MeSH terms

  • Adolescent
  • Adult
  • Aged
  • Aged, 80 and over
  • California / epidemiology
  • Child
  • Child, Preschool
  • Cohort Studies
  • Endovascular Procedures / instrumentation
  • Endovascular Procedures / methods*
  • Female
  • Follow-Up Studies
  • Humans
  • Infant
  • Infant, Newborn
  • Intracranial Aneurysm / epidemiology*
  • Intracranial Aneurysm / mortality
  • Intracranial Aneurysm / surgery*
  • Kaplan-Meier Estimate
  • Longitudinal Studies
  • Male
  • Middle Aged
  • Neurosurgical Procedures / instrumentation
  • Neurosurgical Procedures / methods*
  • Surgical Instruments
  • Survival Rate
  • Treatment Outcome
  • Young Adult