Abstract 32: Residual Perfusion Deficit is Common Post Successful EVT and is Associated With Worse Clinical Outcome

Abstract

Introduction: A significant portion of patients despite achieving successful recanalization following endovascular therapy (EVT) still have some residual perfusion deficit. The objective of this study was to identify the association of residual perfusion deficit with recanalization status and clot presence post EVT. Methods: Patients were included if they were evaluated at one of two comprehensive stroke centers from January 2015 through February 2018, had LVO of the anterior circulation, had baseline MRI pre EVT, and treated with EVT. Independent image reads by two separate readers blinded to target vessel, TICI score, and clinical outcome, evaluated the pre EVT, 2 hours, and 24 hours post EVT MRI for perfusion deficit and clot presence. The MTT and TTP maps post EVT were read separately for residual perfusion deficit, compared to the pre EVT perfusion deficit. Clot presence was read as susceptibility sign on GRE consistent with the vascular territory identified on the pre EVT PWI. Successful recanalization was defined as TICI 2b\3 in the IR suite. Early neurological improvement (ENI) was defined as a reduction of the admit NIHSS by ≥4 points or a score of 0-1 at 24 hours. Results: Fifty-eight patients were included with median age of 58 years, 55% female, 47% Black\African-American, median admit NIHSS of 19, 72% with M1 LVO, 69% treated with IV tPA, 79% achieved TICI of 2b\3, and 52% with ENI at 24 hours. All patients had a perfusion deficit pre EVT with 73% having a corresponding clot on GRE. Following EVT, 76% and 52% of patients had residual perfusion deficit at 2 and 24 hours post EVT, but only 24% and 13%, respectively, still had evidence of clot. For the 46 patients with successful recanalization, 41% still had some residual perfusion deficit at 24 hours, but only 9% still had clot, suggesting inadequate perfusion without a mechanical obstruction. The frequency of ENI at 24 hours was associated with complete reperfusion, 88% versus 46% (p=0.039) at 2 hours post EVT, and 76% versus 33% (p=0.002) at 24 hours post EVT. Conclusions: Residual perfusion deficit on post EVT MRI is common, even with successful recanalization, and is associated with poor outcome. Patients with residual perfusion deficit may benefit from early adjunctive therapy following EVT to improve outcome.