PeRforation EVents During ENdovascular Therapy for Acute Ischemic Stroke

Inclusion Criteria: * Age ≥ 18 years at time of thrombectomy * Acute ischemic stroke with occlusion of one or several intracranial arteries and subsequent thrombectomy. * Target cohort: Occurrence of intracranial perforation during thrombectomy with evidence of contrast extravasation in at least one diagnostic angiography series. * Comparison cohort: No perforation during thrombectomy. Every patient in the comparison group is matched to one patient in the target population. Matching will be carried out with respect to age, gender, participating center and location of the vascular occlusion. Exclusion Criteria: * Presence of a documented rejection * Presence of both ischemic stroke and intracranial hemorrhage on pre-interventional imaging. * Patients with intracranial dissection without active contrast extravasation. * Patients with rupture of a pre-existing intracranial aneurysm during thrombectomy. * Patients with contrast medium extravasation into a venous space instead of free contrast medium extravasation, e.g. the cavernous sinus with consecutive development of a carotid-cavernous fistula.