OXFORD, England, Sept. 1-Patients with ruptured intracranial aneurysms treated with endovascular coils are more likely to be alive and living independently a year later than patients treated with cranial surgery and clipping.
Those are the findings of Andrew J. Molyneux, M.D., and fellow investigators in the International Subarachnoid Aneurysm Trial (ISAT), who reported complete one-year follow-up data in the Sept. 3 issue of The Lancet.
Action Points
- Inform patients that this study shows a lower rate of death and disability at 1 year among patients treated with endovascular coils compared with craniotomy and clipping.
- Inform patients that almost all intracranial aneurysms can be treated with surgery.
ISAT was a randomized multicenter trial comparing clinical outcomes in patients treated with endovascular coiling vs. neurological clipping. In 2002, the trial was halted early because a preliminary analysis showed that coiling was associated with a significantly greater likelihood of disability-free survival.
In the current analysis, which looks at one-year data on nearly all of the patients enrolled, those who received platinum coils had a 23.9% reduction in relative risk for death or disability. The absolute risk reduction was 7.4% for patients treated with coiling, and this early survival advantage was maintained out to seven years.
Patients assigned to coils had a lower rate of post-surgical epilepsy, yet a higher risk of late re-bleeding.
But in an accompanying editorial, neurosurgeon Gavin Britz, M.D., of the University of Washington in Seattle noted that the ISAT study looks only at patients who could benefit from either coiling or clipping.
"Therefore ISAT has shown that, in those patients with aneurysms 10 mm or less in size that have a favorable configuration to be coiled, coiling is associated with less morbidity than clipping," Dr. Britz wrote. "However, this finding cannot be translated into believing that coiling is safer than clipping in all cerebral aneurysms."
He noted that under current practice most middle cerebral artery aneurysms are treated better with clipping than with coiling. In addition, some aneurysms, such as those with a small dome-to-neck ratio or those that have branches coming out of the aneurysm itself have a worse outcome with coiling.
In the ISAT study 2,143 patients with ruptured intracranial aneurysms who were admitted to 42 neurosurgical centers in Britain and Europe were randomly assigned to neurosurgical clipping (1,070) or endovascular coiling (1,073).
The primary outcome was death or dependence (i.e., disability) at one year, as defined by a modified Rankin scale of 3 to 6. The investigators also looked at the rate of re-bleeding from the treated aneurysm and risk of seizures.
In the current analysis, the investigators reviewed outcomes for 1,063 patients randomized to endovascular treatment and 1,055 randomized to neurosurgical treatment. They found that 250 (23.5%) of the coil-treated patients were dead or require dependent care at one year, compared with 326 (30.9%) of the patients treated with neurosurgery. This translated into an absolute risk reduction of 7.4% (95% CI 3.6-11.2, p=0.0001). The early survival advantage was maintained for up to seven years and was significant (log rank p=0.03).
By one year, there had been 14 episodes of seizures in the endovascular therapy group, and 24 in the neurosurgical therapy group (RR 0.52; 95% CI 0.37-0.74).
Confirmed re-bleeding from the target aneurysm was significantly higher among coil-treated patients, who had a relative risk of 1.15 (95% CI, 0.75-1.75).
"The final one-year results presented in this paper reinforce our preliminary findings," Dr. Molyneux and colleagues wrote. "Endovascular coiling, compared with neurosurgical clipping, for ruptured intracranial aneurysms that were anatomically suitable for either procedure, leads to a significant reduction in the relative risk of death or dependency of 23.9% (12.4-33.9). This equates to an absolute risk reduction of 7.4% (3.6-11.2), which is equivalent to 74 patients avoiding death or dependency at one year for every 1,000 patients treated.
"ISAT has only validated endovascular coiling as another viable option in the management of patients with subarachnoid hemorrhage," Dr. Britz wrote. "Each patient and their aneurysm is different and the decision has to be made about what is in the best interest for each patient. None of the treatment options are superior, but rather each has strengths and weaknesses that can be used to decide what is best for each patient. Some patients should be clipped and some should be coiled."
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