Abstract TP130: Prevalence of Fast Progressors of Infarct Growth in Anterior Circulation Large Vessel Occlusions <6 Hours From Onset

Abstract

Background/Purpose: Fast progressors (FP) of infarct growth in anterior circulation large vessel occlusions (LVO) may be prevalent in the <6h period depending on how it is defined. The 3 recently completed randomized trials of endovascular thrombectomy (EVT) on large infarct core volumes (ICV) all used ASPECTS criterion of 3-5 which approximates 70-100mL in absolute volume. We aimed to investigate the prevalence of FP in LVO <6h and how many of these were at or on pace to reach the 70mL or 100mL ICV threshold for EVT selection. Methods: We retrospectively included consecutive stroke patients arriving <6h from symptom onset with ICA and/or M1 occlusion on CTA and had concurrent CT perfusion (CTP). RAPID AI software generated maps of ICV depicted as rCBF<30% and critical hypoperfusion depicted as Tmax>6s. Infarct growth rate (IGR) was calculated as ICV/onset-to-imaging time. FP was defined at 2 levels: as "FP70" with IGR >11.7mL/h (which would result in an ICV >70mL by 6h) and had >=70mL of overall hypoperfusion present; and as "FP100" with IGR >16.7mL/h (which would result in an ICV >100mL by 6h) and had >=100mL of overall hypoperfusion present. Results: 108 patients were included with median (IQR) age of 75.5 (67-85), NIHSS of 20 (12-24), onset time of 2h (1.5-4), median ICV of 11mL (0-40), hypoperfusion volume of 122mL (70-164), and mismatch volume of 86.5mL (58-130). The sites of LVO were ICA 12 (11.1%), M1 73 (67.6%), and both 23 (21.3%). Median IGR for the cohort was 3.8mL/h (0-16.4). 31 FP70 were found (28.7%, 95% CI: 19.5-40.7%) with median IGR of 31.3mL/h (16.8-42). 14 of these (45.2%, 95% CI: 24.7-75.8%) already had ICV>70mL upon arrival, with median of 100mL (86-156) and 8 of 14 also showed mismatch ratio <1.8. 25 FP100 were found (23.1%, 95% CI: 16.2-36.9%) with median IGR of 38.7mL/h (24.6-51.4). 8 of these (32.0%, 95% CI: 13.8-63.1%) already had ICV>100mL upon arrival, with median of 138mL (101-172) and 5 of 8 also showed mismatch ratio <1.8. Conclusion: In a cohort of acute anterior circulation LVO strokes <6h from onset, the vast majority were good candidates for EVT with small to medium size core volumes. However, ~25% were fast progressors that may require more caution in selection, with ICV at or on pace to reach 70-100mL thresholds by 6h.