Abstract 77: Beyond TIMI: Recanalization and Reperfusion with Endovascular Thrombectomy for Acute Ischemic Stroke in Multi MERCI

Abstract

Background: Angiographic definitions for revascularization of arterial occlusion often vary in endovascular stroke trials. Thrombolysis in Myocardial Ischemia (TIMI) scores continue to be used despite inconsistent methods and limited correlation with clinical outcome after stroke. Novel recanalization and reperfusion scores, including the Arterial Occlusive Lesion (AOL) and Thrombolysis in Cerebral Infarction (TICI) scales respectively, have been advanced with limited data on scale metrics. We conducted a prospective analysis of central core lab angiography scores with local site reads in Multi MERCI to establish AOL and TICI metrics of recanalization and reperfusion, linking revascularization with clinical outcomes. Methods: Core lab AOL and TICI scores of two central readers were compared and analyzed with respect to local TIMI grade in Multi MERCI (n=164). In Multi MERCI, a modified TIMI was used, where the final TIMI score was the lowest of the TIMI scores in target vessel and the downstream vasculature. Recanalization and reperfusion were analyzed with respect to baseline clinical variables and 90-day outcomes. Results: Local site TIMI score showed only modest, but statistically significant correlation with AOL recanalization (0.50, p<0.001) and TICI reperfusion (0.65, p<0.001). Inter-rater reliabilities of central readers were excellent for AOL (κ=0.987) and TICI (κ=0.826). AOL and TICI were moderately correlated (0.83, p<0.001). AOL recanalization was associated with time from symptom onset to procedure (-0.23, p=0.005), platelet count (0.16, p=0.043) and SBP < 150 (0.18, p=0.022). TICI reperfusion was also associated with time from symptom onset to procedure (-0.17, p=0.029), current smoking (0.17, p=0.042), CHF (-0.18, p=0.031) and SBP < 150 (0.20, p=0.013). Across all grades, TICI reperfusion was inversely associated with 90-day death (-0.22, p=0.007) and positively associated with good outcomes (0.24, p=0.003). AOL recanalization showed the same trend, though the association was weaker (-0.12, p=0.129; 0.16, p=0.047). TICI 2b/3 strongly predicted 90-day mRS 0-2 (OR 2.73, p=0.004) and decreased mortality (OR 0.29, p<0.001) beyond AOL 2/3 (OR 2.78, p=0.020; 0.56, p=0.125). AOL and TICI exhibited similar relationships across various sites of arterial occlusion. Conclusions: AOL recanalization and TICI reperfusion core lab readings in Multi MERCI revealed excellent reliability and strong predictive value for 90-day clinical outcomes. AOL and TICI scores may discriminate recanalization from reperfusion, allowing further consideration of these distinct aspects of revascularization in future trials.