Introduction: Flow diverter stent (FDS) positioning for internal carotid artery (ICA) requires sometimes a placement of the distal part of the stent in the middle cerebral artery (MCA) and the proximal part in the ICA (MCA-ICA) to insure complete neck coverage and, occasionally, we observed that patients could develop transient neurologic deficits by brain swelling. We hypothesized that this positioning can increase flow disruption at the MCA and can be associated to temporary neurological impairment.
Methods: 151 patients with ICA aneurysms were treated with flow diverter stents from January 2013 to December 2016. We considered only patients with FDS placed from MCA-ICA and at least 3 months of follow-up.
Patients’: clinical and radiological records were assessed during hospitalization and follow-up. Ischemic lesions and intracranial hemorrhage after procedure were differentiate from generalized brain swelling by MRI using diffusion-weighted imaging, fluid-attenuated inversion recovery (FLAIR) and high-resolution 3D T1-weighted imaging with contrast injection.
Results: FDS were placed from MCA-ICA in 7 patients and 5 of them presented temporary neurological impairment and brain swelling. 1 patient presented reversible localized contrast enhanced lesions considered nickel allergy or foreign body reaction, and another patient did not develop any symptom. All 5 patients improved during hospitalization (48-96 hours after symptoms onset). MRI at 3 months did not show any permanent lesion.
Conclusions: In our experience, most of the patients with FDS placed from MCA-ICA developed transient deficit with brain swelling. Even being a transitory event, further investigation is necessary to understand flow changes into the vessels where FDS are placed.