Around 8 in 100,000 people in western countries have a subarachnoid haemorrhage (the bursting of a blood vessel in the brain) every year; around 30% of people die within 24 hours of haemorrhage, and conventional neurosurgical 'clipping' to prevent further rupture of the blood vessels is a high-risk, invasive procedure. The use of endovascular coils--a less invasive option, where a platinum coil is guided through an artery to the weakened vessel in the brain to stop bleeding--has emerged as a new treatment option over the past decade. The International Subarachnoid Aneurysm Trial (ISAT) investigators, led by Andrew Molyneux and Richard Kerr from The Radcliffe Infirmary, Oxford, UK, compared the safety and efficacy of endovascular coiling with standard neurosurgical clipping.
2143 patients from 43 neurosurgical centres in Europe, Australia, and North America were randomly assigned to neurosurgical clipping or endovascular platinum coil treatment. 23.7% (190) patients given endovascular treatment were disabled or dead at 1 year compared with 30.6% (243 patients) who received neurosurgery--a relative reduction in risk of dependency or death approaching 25%, and an absolute reduction of around 7%.
Andrew Molyneux comments: "The results presented here indicate that, for patients with ruptured intracranial aneurysms suitable for both treatments, endovascular coil therapy is significantly more likely to result in survival free of disability 1 year after the subarachnoid haemorrhage than neurosurgical treatment. Longer-term follow up, however, is vital to answer the question of durability of benefit."
In an accompanying Commentary (p 1262), Douglas A Nichols from the Mayo Clinic, USA, and colleagues conclude: "The ISAT investigators are to be congratulated for addressing an important clinical dilemma in a meticulous randomised trial. The study suggests that the small subgroup of good-grade, anterior circulation, small ruptured saccular aneurysms, of such morphology that they would be considered a reasonable candidate for neurosurgical or endovascular therapy, should be considered for coiling if such expertise is available on an emergency basis. However, these data cannot be extrapolated to all other ruptured aneurysms, or to the entire population of unruptured aneurysms."
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Dr Douglas A Nichols, c/o Mary Lawson, Mayo Clinic Communications Department;
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