Reperfusion Injury Is Associated With Poor Outcome in Patients With Recanalization After Thrombectomy

Background: The existence of cerebral reperfusion injury in human beings remains controversial. Thus, we aimed to explore the presence of reperfusion injury in acute ischemic stroke patients with recanalization after mechanical thrombectomy and analyzed its impact on neurological outcome. Methods: We reviewed our prospectively collected database CIPPIS (Comparison Influence to Prognosis of CTP and MRP in AIS Patients, NCT03367286), and enrolled anterior circulation large artery occlusion patients with recanalization after mechanical thrombectomy who underwent (1) computed tomography (CT) perfusion on admission and immediately after recanalization to determine reperfusion region, and (2) CT and/or magnetic resonance imaging (MRI) immediately and 24 hours after recanalization to determine lesion areas. The expansion of lesion between recanalization and 24 hours within reperfusion region was potentially caused by reperfusion, thus termed as radiological observed reperfusion injury (RORI). Based on the imaging modality immediately after recanalization, RORI was further divided into RORI CT and RORI MRI . We first included a small cohort who had performed both CT and MRI immediately after recanalization to validate the consistency between RORI CT and RORI MRI (Study 1). Then the association with RORI CT and poor outcome, defined as 3-month modified Rankin Scale score of 3 to 6, was explored in a larger cohort (Study 2). Results: Study 1 included 23 patients and good consistency was found between RORI CT and RORI MRI (intraclass correlation=0.97, P <0.001). Among 226 patients included in Study 2, a total of 106 (46.9%) were identified with RORI. The ratio of RORI to reperfusion region was 30.1 (16.2, 51.0)% and was independently associated with poor outcome (odds ratio=1.55 per 10% [95% CI‚ 1.30–1.84]; P <0.001). Conclusions: Our findings suggested that RORI was relatively frequent in stroke patients with recanalization after mechanical thrombectomy and associated with poor outcome despite successful recanalization. Registration: URL: https://www.clinicaltrials.gov ; Unique identifier: NCT03367286.