Association of baseline infarct size, reperfusion grade and intracranial hemorrhage in patients undergoing thrombectomy

BACKGROUND: Better reperfusion status results in smaller infarct volumes and better outcomes after thrombectomy. However, if large tissue volumes are already infarcted at baseline, reperfusion might also increase the risk of intracranial hemorrhage. This study aims to investigate the interaction between reperfusion status, baseline ischemic changes, and intracranial hemorrhage following thrombectomy. METHODS: Retrospective analysis of the ESCAPE-NA1 randomized trial. Unadjusted and adjusted logistic regression models were used to estimate the associations of Alberta Stroke Program Early CT Score (ASPECTS) and expanded Treatment In Cerebral Infarction (eTICI) score on post-treatment hemorrhage. Treatment effect modification was assessed by including multiplicative interaction terms (ASPECTS*eTICI) in these models. RESULTS: A total of 1077 patients were included. Median age was 70.8 (IQR 60.7-79.7) and 543 (50.4%) were female. Any intracranial hemorrhage on 24-hour follow-up imaging occurred in 368/1077 (34.2%) patients. There was evidence of modification of the effect of final angiogram eTICI score on any intracranial hemorrhage by baseline ASPECTS (P=0.008). Marginal probabilities showed increased hemorrhage risk for patients with low ASPECTS with increasing final eTICI scores. This association was reversed in patients with small baseline ischemic changes and successful reperfusion. There was no association with symptomatic intracranial hemorrhage or parenchymal hematoma. CONCLUSION: The association of post-thrombectomy reperfusion status and post-treatment hemorrhage may be modified by the extent of baseline ischemia. Reperfusion is associated with reduced risk of hemorrhage in patients with small baseline infarcts, but increased hemorrhage risk in patients with extensive ischemic changes at baseline. However, no significant association was found with symptomatic intracranial hemorrhage or parenchymal hematoma. TRIAL REGISTRATION NUMBER: NCT02930018.