ANGIOGRAPHIC SCREENING AND ELECTIVE SURGERY OF FAMILIAL CEREBRAL ANEURYSMS - A DECISION-ANALYSIS

Up to 6% of cerebral aneurysms may be familial. Because the pattern of inheritance and the prevalence of aneurysms within families are unkno wn, the management of family members at risk of harboring a cerebral a neurysm is currently empirical. We established the prevalence of aneur ysms in the second generation of individuals with familial cerebral an eurysms and determined the possible benefit of angiographic screening and elective surgery of such individuals by using a simple decision an alysis model. Four consecutive families were identified in whom the mo ther and a child had a ruptured cerebral aneurysm. A total of 19 sibli ngs at risk in the second generation were identified. Fifteen underwen t elective cerebral angiography: one had a cerebral aneurysm and two h ad an infundibulum at the origin of the posterior communicating artery . Including the previously known aneurysms, the prevalence of aneurysm s in the second generation was thus established at 29.4%. A decision a nalysis was performed with 2% as the annual risk of rupture, 72.7% as the risk of death or disability with rupture, 0.1% as the risk of angi ography, and 6.5% as the risk of surgery. The benefit in years of surv ival free of sequelae resulting from angiographic screening and electi ve surgery (intervention) over natural history was computed for life e xpectancy corresponding to each quinquennial age group from age 15 to 100 years. Intervention equaled natural history, in terms of years of survival expected with each choice, at a life expectancy of 10.6 years , corresponding to age 76.5 years for men and 80 years for women, and produced a net gain of at least 1 year for patients whose life expecta ncy was 32 years or more, corresponding to age 53.5 years for women an d 49 years for men. Greater benefit was achieved with increasing life expectancy (younger age). The prevalence of aneurysms in the second ge neration when a mother and child have an aneurysm is 29.4%. interventi on produces a benefit of at least 1 year of survival free of sequelae over natural history in such individuals their life expectancy is 32 y ears or more.