Clinical Characteristics of Contrast Leakage and Contrast-Induced Encephalopathy Following Endovascular Treatment for Unruptured Intracranial Aneurysm.

Objective: Contrast-induced encephalopathy (CIE) is a rare but severe complication that can occur following intravascular treatment of intracranial vascular disease. Although CIE is considered a transient neurological disorder, its natural history, pathophysiology, and risk factors are poorly understood. Contrast leakage (CL) is a more frequently observed adverse event than CIE and can lead to CIE. This retrospective study aimed to elucidate the clinical characteristics of CL and CIE and identify the risk factors for each.

Methods: We retrospectively reviewed the medical records of 61 patients with unruptured intracranial aneurysms who were treated at our institution between January 2019 and May 2023. Risk factors for CIE and CL were identified by Fisher's exact test for univariate analysis of categorical variables and by unpaired t-test for continuous variables. One-way analysis of variance (ANOVA) was conducted, followed by the Tukey-Kramer test for multiple comparisons.

Results: Of the 61 patients, 22 (36%) had CL and 4 (6%) had CIE. Among the clinical characteristics analyzed, older age (p = 0.031), larger aneurysm (p = 0.003), lower serum creatinine (p = 0.026), and use of a distal access catheter (p = 0.030) were significant risk factors for CL. CIE occurred only in CL-positive patients (p = 0.014). Of the 4 patients with CIE, neurological symptoms improved within 3 days in 3 patients, and neurological deficit persisted in 1 patient.

Conclusion: Older age, larger aneurysm, lower serum creatinine, and use of a distal access catheter are risk factors for developing CL, and female sex and greater volume of contrast medium are potential risk factors. No risk factors for developing CIE from CL were identified.