Building on controversial data published in New England Journal of Medicine last year, UC San Francisco researchers report that surgically treating unruptured cerebral aneurysms is unnecessary in a large subset of patients.
The UCSF analysis, combining results from numerous investigations, most prominently the NEJM report, showed that treating patients who have small, asymptomatic, unruptured cerebral aneurysms and no history of brain hemorrhage may increase the likelihood that these patients will experience deteriorated health or death.
"Most aneurysms do require surgical treatment, and every patient's situation is unique, so this complex issue needs to be discussed by a patient and his or her physician," said the lead author of the UCSF study, S. Claiborne Johnston, MD, an assistant professor of neurology. "However, our study, based on information that wasn't available before, suggests that in some cases aneurysms should not be treated."
An aneurysm is a widened, or ballooned, area of a blood vessel that results from a weakening in the wall of that vessel. Some four percent to six percent of adults harbor asymptomatic, unruptured cerebral aneurysms, which have an overall rupture rate of between 0.05 percent to 3 percent annually, depending on size. When they rupture, they cause bleeding in the brain. Thirty to 60 percent of patients die as a result, and 15 to 30 percent have permanent disability.
The findings build on results of the International Study of Unruptured Intracranial Aneurysms (ISUIA) reported in NEJM, which had indicated that small aneurysms do not rupture frequently and that the surgical and post-surgical risks associated with treating them were higher than had been thought. But the researchers presenting this study had left the interpretation of the findings up to other research groups, said Johnston. The UCSF study was reported in June in Neurology.