Abstract WP060: 2b or Not 2b? Assessing TICI 2b Reperfusion in Endovascular Thrombectomy for Acute Ischemic Stroke - Extended Study

Endovascular thrombectomy (EVT) is a key treatment for acute ischemic stroke (AIS) caused by large vessel occlusion (LVO). Compared to medical therapy alone, EVT improves neurological outcomes in approximately one in six patients. The Modified Thrombolysis in Cerebral Infarction (mTICI) scale assesses reperfusion after EVT. A score of mTICI 2b—defined as >50% reperfusion of the affected vascular territory—has long been considered the threshold for procedural success. However, whether mTICI 2b reliably leads to favorable long-term outcomes is uncertain. We hypothesize that mTICI 2b is insufficient and propose redefining successful EVT as achieving mTICI 2c or 3. Previously, we demonstrated in a cohort of 81 patients, those with mTICI 2b reperfusion had worse mean mRS at discharge and showed minimal improvement at 90 days compared to mTICI 2c or 3 patients. To improve the power of the study, we performed a retrospective review of AIS patients who received EVT at our comprehensive stroke center from 01/01/2022–06/25/2025. Using the institutional Get-With-The-Guidelines registry, 455 patients with LVO treated to mTICI ≥2b were identified. Two blinded endovascular neurosurgeons reviewed digital subtraction angiograms to assign final mTICI scores. Of the 455, 403 met criteria. For these 403 patients, modified Rankin Scores (mRS) at 24 hours and 90 days post-EVT were obtained from chart review. 24-hour and 90-day mRS scores were available for 323 cases. Primary outcome measures included median mRS at 24h and 90 days and standard deviation. Secondary outcome measures included proportion of patients with functional independence (mRS 0-2), ambulation (mRS 0-3), death and disability (mRS 4-6), and death (mRS = 6) at 24h and 90 days. Patients with mTICI 2b were significantly more likely to have higher median mRS at 24h and 90 days compared to those with mTICI 2c or 3 (90-day median mRS: 4.0 vs 3.0, p=0.01) and performed worse across all 90-day secondary outcome measures. When comparing mTICI2b, mTICI2c, and mTICI3 to each other, there was statistically significant difference in median mRS at 90 days. Our findings show that mTICI 2b reperfusion is associated with significantly worse 90-day outcomes compared to mTICI 2c/3, suggesting it is an inadequate threshold for favorable neurological recovery. We propose redefining optimal reperfusion as mTICI2c or higher. In the future, our analyses will adjust for confounding factors in this association.