Non-negligible clinical relevance of haemorrhagic transformation after endovascular thrombectomy with successful reperfusion in acute ischaemic stroke

AIM To explore the association between haemorrhagic transformation (HT) subtypes and functional outcome in acute ischaemic stroke (AIS) patients with successful recanalization treated by endovascular thrombectomy (EVT). MATERIALS and METHODS Consecutive patients with AIS due to large-vessel occlusion in the anterior circulation, who were treated between January 2015 and June 2019 and achieved successful EVT, were enrolled in this retrospective study. HT was categorized according to the Heidelberg Bleeding Classification. Functional outcome was evaluated using the 90-day modified Rankin Scale (mRS) after stroke onset. Ordinal logistic regression analysis was performed to determine the association of HT subtypes with functional outcomes. RESULTS A total of 243 patients were included for further analysis. Among them, 121 (49.8%) had HT. Ten (4.1%) patients were classified as haemorrhagic infarction (HI) subtype 1, 61 (25.1%) as HI subtype 2, 17 (7.0%) as parenchymal haematoma (PH) subtype 1, and 33 (13.6%) as PH subtype 2. Ordinal logistic regression analysis suggested that HI subtype 2 (adjusted common OR 0.357, 95% CI: 0.192–0.667), PH1 (adjusted common OR 0.254, 95% CI: 0.093–0.696) and PH subtype 2 (adjusted common OR 0.017, 95% CI: 0.006–0.051) were significantly associated with poor functional outcomes. CONCLUSION The present study shows that HI subtype 2, PH subtype 1, and PH subtype 2 are independently associated with poor clinical outcomes in AIS patients with successful recanalization after EVT.