Our understanding of the natural history of unruptured intracranial aneurysms (UIAs) has been limited by studies with short follow-up. Long-term studies are essential for critically evaluating the role of intervention. Juvela and colleagues followed 142 patients with 181 UIA until death or subarachnoid hemorrhage (median follow-up 21 years). During 3,064 person-years, 34 first episodes of aneurysm rupture resulted an annual rupture incidence of 1.1%. The cumulative rate of bleeding at 10, 20 and 30 years were 10.5%, 23.0%, and 30.1%, respectively. Moreover, 13% of patients died due to aneurysm rupture. Cigarette smoking, anterior communicating artery location, decreasing age, and diameter ≥7 mm independently predicted rupture. These results support intervention for UIAs in patients less than 50 years of age regardless of size when there are no treatment contraindications. For older patients with small aneurysms, the risks of intervention must be carefully weighed against aneurysm rupture risk and patient life expectancy.
American Heart Association