In 2002 the International Subarachnoid Aneurysm Trial (ISAT) was stopped early because it showed that the minimally invasive technique, coiling, was more likely to result in survival without disability at one year when compared to neurosurgical clipping. The traditional neurosurgical treatment involves a craniotomy and clipping of the aneurysm to stop further bleeding. The coiling treatment is performed by way of a tiny puncture wound in the groin and through the blood vessels.

At the time of the first report the 1-year follow-up data was available for only 1594 of the 2143 patients enrolled and long-term follow up was not available. Now the researchers report the complete 1-year data and results of long-term follow-up.

Andrew Molyneux and Richard Kerr (Radcliffe Infirmary, Oxford and University of Oxford) and colleagues recruited 2143 patients from 42 neurosurgical centres in Europe, North America, and Australia. The investigators found that 250 of 1063 (23•5%) patients allocated to endovascular coiling treatment were dead or dependent at one year compared with 326 of 1055 (30•9%) patients allocated to neurosurgery and clipping. The researchers found that the early survival advantage was maintained up to 7 years. They also found that the risk of late rebleeding was low but more common after endovascular coiling than after neurosurgical clipping. Patients assigned coiling also had a substantially lower risk of seizures than patients allocated to clipping.

Molyneux comments: “A crucial issue for endovascular techniques was the uncertainty about the longterm durability of aneurysm occlusion with coils and whether it protects from further aneurysm rupture. ISAT gives the most reliable evidence to date to answer this question. This will save about 74 patients in 1000 from death or disability, reducing the risk of death or disability by about 24%.”; Source: The Lancet