Preliminary results of a long-term study suggest that coils inserted into burst aneurysms in the brain decrease by 25 percent the risk of patient death and disability during the first year after the procedure, according to a report published in the Oct. 26 issue of The Lancet. Aneurysms are abnormal ballooning of artery walls.
"The results with coiling were so favorable the trial was ended ahead of schedule," says Kieran Murphy, the primary investigator for the study at Johns Hopkins and associate professor of radiology and neurological surgery in the School of Medicine.
The study, called the International Subarachnoid Aneurysm Trial, or ISAT, examined patients at 44 medical centers in Europe, Australia and North America whose aneurysms were suitable for treatment with either surgical clipping or coiling. Those with aneurysms shaped in such a manner that prevented the retention of the coils as well as those for whom surgical clipping was not possible were excluded from the study. Of 2,143 patients for whom both treatments were appropriate, 1,073 were randomly selected to receive the coils, and 1,070 were chosen to undergo surgical clipping.
Surgical clipping, currently the most commonly used treatment for brain aneurysms, requires opening the skull and placing a metal clip across the neck of the aneurysm to stop the bleeding. In coiling, a catheter is inserted through an artery in the leg up into the brain to fill the aneurysm there with tiny platinum coils.
The coils, Murpy says, are like "miniature slinkies that are folded gently into the aneurysm like a ball of yarn, one by one, to stop the bleeding." Noting that the procedure also can be used to prevent aneurysms from bursting, he adds, "With coiling, we can either help fix the damage or prevent it from occurring."
Murphy likens brain aneurysms to ticking time bombs. "They can lurk for years without causing symptoms; then, without warning, they can burst, spilling blood into the brain with potentially catastrophic results.
The ISAT results offer the first large-scale clinical evidence that coiling may be a new, useful method for treating these types of aneurysms. The National Stroke Association notes that as many as 18 million Americans have unruptured aneurysms. Of those, 30,000 people each year will suffer a ruptured aneurysm, and as many as 15 percent of them will die before reaching the hospitals. An additional 50 percent will die within the first 30 days after the rupture. The outlooks for survivors also can be grim--about half suffer some form of permanent disability.
Daniele Rigamonti, one of the study's co-authors and professor of neurosurgery at Johns Hopkins, emphasizes that the coils are not suitable for every aneurysm patient. "For patients with certain types of aneurysms, those lacking necks to prevent the coils from slipping out of the aneurysm, coiling is not an option; these patients are best treated by surgical clips," he says. "However, in either case, it is imperative that patients be evaluated by a team of specialists in interventional neuroradiology and neurosurgery to determine the optimum treatment approach."
Both Murphy and Rigamonti emphasize that longer follow-up studies of the ISAT patients are needed to ascertain if the coils remain effective over time.
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