Epidemiologic and anatomic aspects comparing incidental and ruptured intracranial aneurysms: A single centre experience

The feasibility of multicentric international data such as integrated in the PHASES score for patient counseling in unruptured intracranial aneurysms has recently been challenged. To determine, whether this data is applicable to local populations in a restricted catchment area, we performed a retrospective mono-centric analysis comparing patients with ruptured aneurysms to patients with incidental aneurysms. 200 patients with unruptured aneurysms and 197 patients after aneurysmal subarachnoid hemorrhage were analyzed for risk factors differing between the groups and to the general German population. Subgroup analysis was performed for 25 patients harboring multiple aneurysms, in 19 patients with intracavernous aneurysms and in 77 women of childbearing potential. While the preponderance of female patients was confirmed, significantly more men figured in the patient group with subarachnoid hemorrhage (36.4%) than among unruptured aneurysms (25%). Patients with bleeding events were significantly younger (51.6 years) than patients with incidental aneurysms (57.8 years). The rupture risk prediction of the PHASES score concerning aneurysm size below 7 mm and patient age over 70 years could not be confirmed, instead score points correlated to the clinical outcome after rupture. In our population, pregnant women were not overrepresented. Intracavernous carotid aneurysms contributed to the low risk profile of giant aneurysms. Thus, recommendations from pooled international data have to be adapted cautiously to local circumstances. We retained seven items with predictive value for outpatient counseling: age, smoking, hypertonus and concurrent vascular aberrations as patient characteristics and irregular shape, (increasing) largest diameter and the harboring vessel for the aneurysm.