International Subarachnoid Aneurysm Trial (ISAT) of neurosurgical clipping versus endovascular coiling in 2,143 patients with ruptured intracranial aneurysms: a randomised trial.

Molyneux A, Kerr R, Stratton I, Sandercock P, Clarke M, Shrimpton J, Holman R.
Lancet. 2002: 360: 1267-74.

Purpose: Determine whether endovascular treatment compared with neurosurgical treatment reduced the proportion of patients dependent or dead, defined by a modified Rankin score of 3-6

METHODS:
2143 patients randomly assigned endovascular coil treatment (n=1070) or neurosurgical clipping (n=1073). Most randomized patients had good-grade (88 percent in WFNS grades I and II), small anterior circulation aneurysms (92 percent less than 11 mm in size).

RESULTS:

RESULTS:
Endovascular
(n=801)
Surgical
(n=793)
Died or had mRS score 3-6 at 1 year
23.7%
30.6%

– Relative risk reduction favoring coiling is 22.6%. Absolute risk reduction is 6.9%.*

– The risk of rebleeding during the first year was 2.4 percent for the endovascular group and 1.0 percent for the surgical group. Rebleeding after 1 year was 2 per 1,276 follow-up years for coiling patients and 0 per 1,081 follow-up years for surgical patients.

CONCLUSION:
In ruptured brain aneurysm patients, equally suited for both treatment options, endovascular coil treatment produces substantially better patient outcomes than surgery in terms of survival free of disability at one year.