Among elderly patients with unruptured cerebral aneurysms, the size and location of aneurysms, as well as patient age, are significant risk factors for aneurysm rupture, according to research published November 24, 2015, in Neurology.
Stratifying the risk of rupture in elderly patients is important “to effectively perform preventive surgical treatment for the patients who are at a high risk of rupture,” said Tomohito Hishikawa, MD, of the Department of Neurological Surgery at Okayama University Graduate School of Medicine, Dentistry, and Pharmaceutical Sciences in Japan, and colleagues.
The risk associated with surgical treatment of unruptured aneurysms in elderly patients, however, makes the management of these patients more difficult, the researchers said.
To identify risk factors for the rupture of unruptured cerebral aneurysms in elderly Japanese patients, Dr. Hishikawa and colleagues analyzed pooled data from three prospective studies that evaluated the natural course of unruptured cerebral aneurysms in Japanese patients. The researchers included 1,896 patients age 70 or older with 2,227 unruptured cerebral aneurysms. Patients had a mean age of 74.3, 10.9% were age 80 or older, and 72.9% were female. The mean aneurysm size was 6.2 mm.
During an average follow-up period of 802.7 days, 68 patients had subarachnoid hemorrhages, resulting in an overall annual rupture risk of 1.6%. The cumulative rate of subarachnoid hemorrhage for all patients was 3.8% at two years after diagnosis, and 6.3% at five years after diagnosis.
Multivariable analysis per patient revealed that patient age of 80 or older and internal carotid-posterior communicating artery aneurysms independently predicted aneurysm rupture, with hazard ratios of 2.02 and 2.45, respectively.
Aneurysm size of 7 mm or larger also predicted aneurysm rupture. The hazard ratios for aneurysms of 7–9 mm, 10–24 mm, and 25 mm or greater were 3.08, 7.82, and 43.31, respectively.
Female sex, multiple aneurysms, and basilar artery aneurysm were significant risk factors for rupture by univariable analysis, but they did not reach statistical significance by the multivariable analysis.
“When deciding [on a] therapeutic strategy for elderly patients with unruptured cerebral aneurysms, we have to consider various factors, such as the difference between chronological age and physiologic age, the difference in life expectancy between patients age 70 to 79 years and those older than 80 years, and one’s view of life and death,” the researchers said.
Unlike in prior research, there was no significant difference between men and women in the prevalence of aneurysms larger than 7 mm. “This [lack of difference] is probably one of the reasons why female sex disappeared as a risk factor for aneurysm rupture in elderly patients with unruptured cerebral aneurysms in our pooled analysis,” said the researchers. Prior studies have found that geographic region is related to the risk of aneurysm rupture, so the findings of this study “should be applied with caution” to patient populations in other countries, the investigators said.
—Jake Remaly
