Retreatment of previously treated intracranial aneurysm: Procedural complications and risk factors for complications

Objective Intracranial aneurysm (IA) is a frequent vascular malformation that can be managed by endovascular treatment (EVT) or microsurgery. A previously treated IA can recanalize, which may require further treatment. The aim of our study was to evaluate procedural complications related to IA retreatment and their risk factors. Methods All patients retreated for IA between 2007 and 2017 in 4 hospitals were included. We retrospectively reviewed the frequency of procedural complications of IA retreatment, defined as death or ≥ 1-point increase in modified Rankin score 24 h after the procedure. We then screened for risk factors of procedural complications by comparing the characteristics of patients with and without complications. Results During the inclusion period, 4,997 IAs were treated in our 4 institutions. Of these, 237 (4.7%) were retreated. 29 (12.2%) had ≥ 1 procedural complication. However, severe complications, defined as death or dependency at 1 month, occurred only in 3 patients (1.3%). The only risk factor for complications was microsurgical clipping as retreatment. Conclusions Procedural complications during IA retreatment were frequent but, in most cases, retreatment did not lead to death or severe disability. The only risk factor for complications of IA retreatment was clipping as retreatment. However, the design of the study did not allow any conclusion to be drawn as to the optimal means of aneurysm retreatment, and further studies are needed.