Reversible brain edema associated to flow diverter stent procedures: a retrospective single-center study to evaluate frequency, clinical evolution, and possible mechanism

Background Hemorrhage and ischemia after flow diverter stent (FDS) procedures for intracranial aneurysms are the most common complications and have been extensively described. Temporary brain edema (TBE) is an unknown complication that could be associated with particular FDS procedures.

Objective To estimate the frequency, clinical presentation, imaging findings, and possible mechanisms associating TBE with FDS.

Methods Unruptured aneurysms treated with FDS implantation performed in our service from June 2015 to March 2018 were reviewed. Medical antecedents, endovascular procedure, clinical assessments before and after treatment, aneurysm characteristics, and image records were collected. Artery diameters of patients in whom TEB developed were also calculated to investigate any correlation between TBE and anatomic descriptors.

Results A total of 179 FDS procedures in 176 patients were reviewed. Six patients (3.4%) presented with symptomatic TBE, and all TBE patients had undergone FDS implantation from the middle cerebral artery (MCA) to the internal carotid artery (ICA). A Pearson product-moment correlation coefficient (PPCC) found smaller MCA diameters and MCA/ICA ratios in these 6 patients (respectively PPCC = −0.619, P < 0.04; PPCC = −0.647, P < 0.03). Hemorrhagic and ischemic complications were less frequent than TBE (2.3% and 1.1% vs. 3.4%).

Conclusions TBE was more frequent than ischemic or hemorrhagic complications after FDS in this study. TBE seemed to be associated with a particular FDS positioning in small arteries, inducing flow changes and disruption of the blood–brain barrier.