The Source for Neurovascular News and Education

August 10, 2020


A new look at data from the well-known study reveals that clipping offers more durability than coiling, with otherwise similar outcomes.


Patients with saccular aneurysms achieve similar functional outcomes no matter whether they undergo clipping and coiling, but clipping is the longer-lasting option, according to a recent subanalysis of data from the pivotal Barrow Ruptured Aneurysm Trial (BRAT).

The findings, which reveal lower rates of retreatment and higher rates of complete occlusion at 6 years with clipping, were published online February 24, 2017, ahead of print in the Journal of Neurosurgery.

Lead author Robert F. Spetzler, MD (St. Joseph’s Hospital and Medical Center, Phoenix, AZ), explained to Neurovascular Exchange that it was important to look at the BRAT findings specifically with respect to saccular aneurysms. “These are the aneurysms we treat day in and day out,” he said. “They are by far the most common, and they are the aneurysms that were included in the only other large, prospective randomized trial, which is the ISAT study.”

Despite the fact that BRAT is now several years old, Spetzler asserted that the findings remain relevant. For now, he said, the endovascular treatment option with the most solid data behind it is coiling.

 “As soon as you add on additional hardware, additional technology, you also add on increased risk,” he said. “We have not had a prospective trial, for example, that looks at aneurysms that were not included in the study, the kind of aneurysms that we are now treating with the Pipeline or other flow diverting devices. And until you have a head-on, prospective, randomized trial, it is very hard to eliminate your own bias in what is best.”

For BRAT, 471 patients with nontraumatic subarachnoid hemorrhage were randomized to treatment using clipping or coiling. The present subanalysis specifically evaluated outcomes of the 362 patients (77%) whose bleeding arose from a saccular aneurysm. These patients were assigned equally to clipping or coiling cohorts. Three patients in each group died prior to treatment, leaving a total of 178 patients treated in each cohort. Crossover was permitted, with 1 patient (1%) crossing over from clipping to coiling and 64 patients (36%) crossing over from coiling to clipping.

Based on an intent-to-treat analysis, the rate of poor outcome (mRS > 2) was similar for both groups after up to 6 years of follow-up. After initial hospitalization, however, the need for retreatment was significantly higher in the coiled group. In addition, the rate of complete aneurysmal obliteration at 6 years was significantly higher with clipping than with coiling.

Six-Year Outcomes (Intent-to-Treat Analysis)




P Value

mRS > 2




Rate of Retreatment



< 0.001

Rate of Complete Occlusion



< 0.001


‘Strong Case’ for Surgery

“When you look specifically at anterior circulation aneurysms,” said Spetzler, ‘there is certainly no better outcome with embolization. The degree of occlusion and the risk of recurrent treatment favors surgery. So, I think a strong case can be made that surgery remains a solid and excellent option for these aneurysms.”

Spetzler would like to see these findings confirmed in a multicenter prospective trial, but he is doubtful that will occur. “The practice patterns are so set; the biases are so firm. . . . When physicians or the patients and families have a firm conviction that one is better than the other, then it is extremely difficult to carry out a prospective trial,” he said, adding, “The beauty and strength of BRAT was that every patient with a subarachnoid hemorrhage was entered, if possible. We entered them before we even knew they had an aneurysm.” It would be extremely difficult to get multiple centers to agree to do the same today, he said.



Spetzler RF, Zabramski JM, McDougall CG, et al. Analysis of saccular aneurysms in the Barrow Ruptured Aneurysm Trial. J Neurosurg. 2017;Epub ahead of print.



Spetzler reports no relevant conflicts of interest.


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