Materials and Methods Patients and Follow-Up

Patients who survive subarachnoid hemorrhage (SAH) have a higher rate of new SAH than the general popula-tion, even after successful treatment of the initial aneurysm, because of de novo and recurrent aneurysms.1–3 Aneurysms in the first 2 decades of life comprise about 1 % to 4 % of all intracranial aneurysms.4–7 Long-term angiographic follow-up studies in pediatric intracranial aneurysm patients with mean follow-up times of only 4 to 6 years5,8,9 show de novo aneu-rysm formation rates of 13 % to 23%.4,5,9 We gathered data on long-term clinical and angiographic follow-up studies of pediatric aneurysm patients in a single-center consecutive series. We assessed the risk of these patients to harbor de novo and recurrent aneurysms, and the risk factors associated with new angiographic findings in a long follow-up