The Barrow Ruptured Aneurysm Trial: 3-year results

J Neurosurg. 2013 Jul;119(1):146-57. doi: 10.3171/2013.3.JNS12683. Epub 2013 Apr 26.


Object: The authors report the 3-year results of the Barrow Ruptured Aneurysm Trial (BRAT). The objective of this ongoing randomized trial is to compare the safety and efficacy of microsurgical clip occlusion and endovascular coil embolization for the treatment of acutely ruptured cerebral aneurysms and to compare functional outcomes based on clinical and angiographic data. The 1-year results have been previously reported.

Methods: Two-hundred thirty-eight patients were assigned to clip occlusion and 233 to coil embolization. There were no anatomical exclusions. Crossovers were allowed based on the treating physician's determination, but primary outcome analysis was based on the initial assignment to treatment modality. Patient outcomes were assessed independently using the modified Rankin Scale (mRS). A poor outcome was defined as an mRS score>2. At 3 years' follow-up 349 patients who had actually undergone treatment were available for evaluation. Of the 170 patients who had been originally assigned to coiling, 64 (38%) crossed over to clipping, whereas 4 (2%) of 179 patients assigned to surgery crossed over to clipping.

Results: The risk of a poor outcome in patients assigned to clipping compared with those assigned to coiling (35.8% vs 30%) had decreased from that observed at 1 year and was no longer significant (OR 1.30, 95% CI 0.83-2.04, p=0.25). In addition, the degree of aneurysm obliteration (p=0.0001), rate of aneurysm recurrence (p=0.01), and rate of retreatment (p=0.01) were significantly better in the group treated with clipping compared with the group treated with coiling. When outcomes were analyzed based on aneurysm location (anterior circulation, n=339; posterior circulation, n=69), there was no significant difference in the outcomes of anterior circulation aneurysms between the 2 assigned groups across time points (at discharge, 6 months, 1 year, or 3 years after treatment). The outcomes of posterior circulation aneurysms were significantly better in the coil group than in the clip group after the 1st year of follow-up, and this difference persisted after 3 years of follow-up. However, while aneurysms in the anterior circulation were well matched in their anatomical location between the 2 treatment arms, this was not the case in the posterior circulation where, for example, 18 of 21 posterior inferior cerebellar artery aneurysms were in the clip group.

Conclusions: Based on mRS scores at 3 years, the outcomes of all patients assigned to coil embolization showed a favorable 5.8% absolute difference compared with outcomes of those assigned to clip occlusion, although this difference did not reach statistical significance (p=0.25). Patients in the clip group had a significantly higher degree of aneurysm obliteration and a significantly lower rate of recurrence and retreatment. In post hoc analysis examining only anterior circulation aneurysms, no outcome difference between the 2 treatment cohorts was observed at any recorded time point. CLINICAL TRIAL REGISTRATION NO.: NCT01593267 ( ).

Publication types

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

MeSH terms

  • Adult
  • Aged
  • Aneurysm, Ruptured / mortality
  • Aneurysm, Ruptured / surgery*
  • Aneurysm, Ruptured / therapy*
  • Cross-Over Studies
  • Embolization, Therapeutic / methods*
  • Female
  • Follow-Up Studies
  • Humans
  • Intracranial Aneurysm / mortality
  • Intracranial Aneurysm / surgery*
  • Intracranial Aneurysm / therapy*
  • Longitudinal Studies
  • Male
  • Middle Aged
  • Multivariate Analysis
  • Neurosurgical Procedures / methods*
  • Postoperative Complications
  • Retreatment / statistics & numerical data
  • Severity of Illness Index
  • Subarachnoid Hemorrhage / mortality
  • Surgical Instruments
  • Treatment Outcome

Associated data