We hypothesize mTICI2b is insufficient and propose redefining successful EVT as achieving mTICI ≥2c.

Endovascular thrombectomy (EVT) is a key treatment for acute ischemic stroke (AIS) caused by large vessel occlusion (LVO). The Modified Thrombolysis in Cerebral Infarction (mTICI) scale assesses post-EVT reperfusion. A score of mTICI 2b—or >50% reperfusion of the affected vascular territory—is considered the threshold for success. However, whether mTICI 2b reliably leads to favorable long-term outcomes is uncertain.

We previously demonstrated in 81 patients that mTICI2b reperfusion resulted in worse mean mRS at discharge and 90 days compared to mTICI 2c/3. To improve the study's power, we performed a retrospective review of AIS patients who received EVT at our comprehensive stroke center from 1/1/22–6/25/25. 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 mTICI scores. Of the 455, 403 met criteria and modified Rankin Scores (mRS) at 24h and 90 days post-EVT were available for 323 cases. Primary outcome measures included 24h and 90-day median mRS and standard deviation. Secondary outcome measures included 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 mTICI2b were significantly more likely to have higher median mRS at 24h and 90 days compared to those with mTICI2c/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. 

mTICI2b reperfusion is associated with significantly worse 90-day outcomes compared to mTICI2c/3, suggesting it is an inadequate threshold for favorable recovery. We propose redefining optimal reperfusion as ≥mTICI2c. Future analyses will adjust for factors confounding this association.