Abstract TMP2: Postoperative Luxury Perfusion on Arterial Spin Labeling MRI Indicates Reperfusion Injury and Hemorrhagic Complication After Endovascular Mechanical Thrombectomy

Background and Purpose: Endovascular thrombectomy is of benefit to most patients with acute ischemic stroke caused by major intracranial vessel occlusion. Reperfusion injury is, however, one of the critical complications after successful recanalization, which has not been fully evaluated. The aim of this prospective study was to assess the impact of hyper-intensity signal on postoperative arterial spin labeling (ASL) MR imaging on hemorrhagic complications and clinical outcome after endovascular treatment. Methods: Consecutive patients showing acute stroke with major intracranial vessel occlusion were prospectively analyzed. All the patients underwent endovascular thrombectomy, and MR imaging including ASL was performed at pre-, postoperative day 1 and day 7. Clinical and radiological outcomes were evaluated especially focusing on arterial spin labeling findings. Results: Of 81 patients, 21/81 (25.9%) showed hyper-intensity signal on ASL (ASL+) at postoperative day 1. There were no significant differences in baseline characteristics between the groups with and without ASL+, including preoperative NIH stroke scale, door to puncture time, occlusion vessel and TICI score. Interestingly, 15/21 (71.4%) patients developed minor bleeding or hemorrhagic changes in ASL+ group, which was detected only in 3/60 (5.0%) in ASL- group. Modified Rankin Scale was not different between the groups at postoperative day 90 under strict control of blood pressure. Multivariate regression analysis showed that ASL+ is significantly related to postoperative hemorrhagic complications (Adjusted OR: 21.68, P=0.004). Conclusions: Postoperative hyper-intensity signal on ASL MRI indicates vasoparalysis and luxury perfusion even successful recanalization after endovascular thrombectomy, which has a risk for hemorrhagic complications.