Large core trial: State of Practice

Background: This review critically analyzed recent publications on large-core Randomized Controlled Trials (RCTs). Six RCTs demonstrated the superiority of mechanical thrombectomy over the best medical treatment in patients with low ASPECTs. However, the use of ASPECTs to define the ischemic core has limitations in detecting ischemic changes beyond the middle cerebral artery (MCA) territory. This review evaluates the implications of this choice on the external validity of the trials.

Methods: The study evaluated ASPECTS reliability by examining the anatomical details of occlusion location, collateral blood flow, and perfusion imaging. An analysis comparing the HERMES collaboration with six RCTs on large-core infarcts was conducted to investigate how the occlusion site affects infarct size and salvageable brain tissue, as well as to support pathophysiological assessment.

Key Message: RCTs indicated a trend toward more proximal occlusions in large-core trials compared to HERMES collaboration, unpredictably increasing the mismatch between the ischemic core and salvageable tissue. ASPECTS inadequately depicted ischemic changes outside the proximal MCA occlusion, causing potential misinterpretations. Perfusion imaging identified core volume and salvageable areas better than ASPECTS alone by including all at-risk tissues, not just the MCA. This review advocates redefining infarct core assessment in large-core RCTs, prioritizing perfusion imaging over ASPECTS. It emphasizes the significance of the occlusion site in large-core stroke for clinical decisions and calls for research to refine the imaging criteria for thrombectomy eligibility.