Abstract WMP93: Additional Endovascular Thrombectomy Passes After An Initial TICI2b Reperfusion To Improve Final Reperfusion Grade Does Not Improve Functional Outcomes

Background: First pass complete or near complete reperfusion defined as a modified Thrombolysis in Cerebral Infarction (mTICI) 2c/3 is the target for endovascular thrombectomy (EVT). Here, we examine whether additional passes in patients who achieve a first pass mTICI 2b, in order to attain mTICI 2c/3, improve clinical outcomes. Methods: From our prospectively maintained institutional registry at 4 comprehensive stroke centers, we identified patients treated with EVT (11/2017-12/2021). Per-pass mTICI grades were recorded at the time of the procedure. The primary outcome was functional independence rates at 90 days (mRS 0-2) in first pass mTICI 2b patients compared with multiple passes mTICI 2c/3 patients. Results: A total of 857 EVT patients were identified in the study period. The median age was 68 [58-79], 49.7% were female, median NIHSS was 16 [11-21], median ASPECTS was 9 [7-10], and 64% had MCA occlusions. First pass mTICI 2c/3 (FP-mTICI 2c/3) was achieved in 342 (39.9%) cases and first pass mTICI 2b (FP-mTICI 2b) was achieved in 123 (14.4%) patients. Of the FP-mTICI 2b group, 27 (21.9%) patients received additional passes to reach complete reperfusion. Good functional outcome was observed in 159 patients (46.5%) of the FP-mTICI 2c/3 reperfusion group as compared to 27 patients (28.1%) in the FP-mTICI 2b group (p=0.002). The rate of good functional outcome was not significantly different for patients who achieved mTICI 2c/3 following additional passes after a first pass mTICI 2b (28.1 vs. 29.6%, first pass mTICI 2b vs. first pass mTICI 2b with final mTICI 2c/3, p=0.954). Adjusted for age, sex and NIHSS at presentation, patients with FP-mTICI 2c/3 had a better chance of good outcomes than patients with FP-mTICI 2b (OR 2.23, 95% CI [1.38-3.62]). In multivariable analysis adjusting for age, sex, and NIHSS at presentation, patients with FP-mTICI 2b reperfusion followed by improved reperfusion to mTICI 2c/3 did not have better outcomes than patients with FP-mTICI 2b reperfusion (OR 1.14, 95% CI [0.41-3.12]). Conclusions: Additional EVT passes to achieve mTICI 2c/3 following a first pass mTICI 2b does not lead to significant improvement in functional outcomes. This study suggests that EVT can be terminated if FP-mTICI 2b-3 is achieved.