Intracranial Aneurysm Expansion Might Cause Neurological Deterioration After Flow Diverter Treatment.

OBJECTIVE: Patients with large and giant intracranial aneurysms (IAs) can experience neurological deterioration within 6 months after successful flow diverter (FD) placement. The purpose of the present study was to assess whether the occurrence of neurological deterioration can be linked to IA expansion within 6 months after FD treatment. METHODS: From 2010 to 2016, 45 FD procedures were performed in 44 patients with a large or giant IA. From this group, we selected all patients (14 patients with 15 IAs) with neurological deterioration within 6 months after FD treatment. All these patients had undergone follow-up imaging studies within the same period. The patients were then divided into 2 groups, those with mass effect-related and those with ischemia-related symptoms. The volumes of all treated IAs were determined through manual segmentation of the available pre- and postoperative imaging studies to determine IA expansion after FD treatment. To rule out false-positive findings, we only considered an IA volume increase of >20% after FD treatment as a true IA volume increase. RESULTS: During the follow-up period, 6 IAs increased in volume and 9 IAs did not. More patients presenting with mass effect-related symptoms showed IA expansion (6 of 10 IAs) compared with patients presenting with ischemia-related symptoms (0 of 5 IAs; Fisher's exact test, 2-sided; P = 0.044). CONCLUSION: The volume of large and giant IAs can increase in the first 6 months after FD treatment. More patients presenting with mass effect-related symptoms showed IA expansion than patients with ischemia-related symptoms.