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THURSDAY, July 10, 2003 (HealthDayNews) -- As scary as a looming brain aneurysm seems, most people who have one don't need emergency surgery, claims the largest study yet of how patients with the condition fare over time.
Indeed, the risk of operating on many unruptured aneurysms may outweigh the potential benefits, especially in older patients with relatively small artery defects, the study found.
"Most aneurysms in the general population don't rupture, but it's important to sort out which ones are more likely to," says Dr. David O. Wiebers, a neurologist at the Mayo Clinic and leader of the research, which appears in the July 12 issue of The Lancet. "In some cases, the risk is so low it's not advisable to do any procedure."
However, Wiebers adds, in patients for whom quick action is needed, doctors have ways of repairing aneurysms: "There are more options now than there ever have been before, and the technical quality is improving as time goes on."
According to the Brain Aneurysm Foundation, roughly 2 million Americans live with unruptured brain aneurysms -- areas of weakness in an artery wall that allow small balloon-like cul-de-sacs to form. Each year, 30,000 people in this country suffer ruptured aneurysms. Half die within minutes, while many of the rest either die soon after or face severe debilitation. Although unruptured aneurysms can cause headaches and other symptoms they often do not, lying in wait to be discovered on brain scans for other reasons, such as trauma or migraine headaches.
The latest study included 4,060 men and women with unruptured brain aneurysms who were seen at 61 clinics in the United States, Canada and Europe. Of those, 1,917 had surgery to repair the pouched vessels and 451 had small coils packed into the bulges to create clots and wall off the area. That left 1,692 patients whose aneurysms weren't repaired.
The patients were followed for as long as nine years, during which time 51 suffered a rupture. But the risk of a breach was minuscule -- almost 0 percent -- for people whose aneurysms were smaller than seven millimeters across. The rupture rate jumped to 3.3 percent for aneurysms between 7 millimeters and 12 millimeters wide, and to17 percent for those wider than that.
Several other factors also influenced the odds that an aneurysm would rupture. Aneurysms toward the back of the brain, though rarer, were more prone to breaking than those in the front. People with a previous history of a ruptured aneurysm in another site were more likely to have a break, too.
Older people weren't more likely than younger patients to have their aneurysms rupture, but they tended to do worse when operated on.
Patients who had coil implants did better in the short run than those who had surgery to clip off the bulging artery. Their risk of death or serious disability was 20 percent to 30 percent lower after a year.
"The thing that's not known is the long-term outcomes and durability of the coils," Wiebers says. "That's what we're hoping to do in the next phase of this." Average follow-up in the study ran four to five years, and the researchers hope to extend that to 10 years or so, he says.
Data from an earlier phase of the international study suggested that unruptured aneurysms smaller than about 10 millimeters didn't require repair. "The magical number was 10, now it's seven," says Dr. Jacques E. Dion, a brain surgeon at Emory University who is familiar with the new findings. "Is it going to hold there? I don't know."
Dr. Kieran Murphy, a neurosurgeon at Johns Hopkins University and an expert in coil therapy, agrees more evidence of their long-term effectiveness would be nice. "Always it's prudent to look at how much coil compaction takes place over time," Murphy says. Yet coil technology is advancing rapidly, he adds, and newer devices are designed to be more rugged than previous models.
Ultimately, Murphy says, the most important thing for patients is to get the option of surgery or coil implants -- and that often doesn't happen because coiling is still relatively uncommon.
More information
Try the Brain Aneurysm Foundation or the National Institute of Neurological Disorders and Stroke for more on aneurysms and their consequences.
