Current Status of Randomized Trials Comparing Coiling and Clipping of Aneurysms

Robert F. Spetzler, MD1, Cameron G. McDougall, MD1, Felipe C. Albuquerque, MD1, Joseph M. Zabramski, MD1, Peter Nakaji, MD1

1Phoenix, AZ United States

Keywords: aneurysm clip, coiling, aneurysm, hemorrhage, randomized trial

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     We previously reported the one and three year results of the Barrow Ruptured Aneurysm Trial (BRAT). At one year the intent to treat results favored coiling, at three years there was no longer a statistical difference between the two treatments (p=0.20) although there was still an absolute difference of 6.1% favoring coiling.
     We are comparing the BRAT results to the other randomized trials: ISAT and the Finnish aneurysm trial.
     238 patients were assigned to clipping and 233 to coiling.
     Cross overs were allowed based on the treating physician’s determination, but primary outcome analysis was based on the initial assignment to treatment modality. A poor outcome was defined as a mRS score > 2. Thirty-eight percent of the intent-to-coil patients were crossed over to clipping. Based on a mRS > 2, there was no significant difference in poor outcomes (p=0.20) between patients assigned to clipping (34.5%) and those assigned to coiling (28.4%) at three years although an absolute difference of 6.1%remained in favor of coiling. The degree of aneurysm obliteration (p = 0.01), rate of aneurysm recurrence (p = 0.01), and rate of retreatment (p = 0.01) were significantly better in the group that underwent clipping compared to the group that underwent 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 two assigned group across follow up (i.e., at discharge, 6 months, 1 year, or 3 years). The outcomes of posterior circulation aneurysms were significantly better in the coiling group than in the clipped group after the first year of follow up, and this difference persisted after 3 years of follow up.
     There was no difference in outcome between coiling and clipping at one year. There were four hemorrhages in the coil group (6% - 4/67), two from previously coiled aneurysms, in the clip group there were 2 hemorrhages (3% - 2/71) from de novo aneurysms. ISAT: At five years the previously reported outcome at one year favoring coiling had disappeared. Only 23% of eligible patients were entered into ISAT. Therefore, most patients were excluded from the study. Of those entered, 97% of the aneurysms were located in the anterior circulation. After three months 9% of coiled aneurysms required retreatment, subsequent SAH was higher in the coiled cohort.
     This is a retrospetive study.
     The devastating outcomes of patients with aneurysmal SAH, irrespective of treatment, leave considerable room to improve the management of this disease. Because specific benefits and risks are inherent to both coiling and clipping, patients with an aneurysm need access to expertise in both treatment modalities. .
     With the results of both ISAT and BRAT having reached equipoise and with BRAT convincingly demonstrating that patients with a SAH can be randomized and treated promptly, a new trial for the entire aneurysm population that incorporates recent advances in both treatment modalities is justified


Project Roles:

R. Spetzler (), C. McDougall (), F. Albuquerque (), J. Zabramski (), P. Nakaji ()