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

Abstract

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.

iSPAN: Improved prediction of outcomes post thrombectomy with Machine Learning

“…Even recent developments that focus strictly on interpretability suggest the use of additional algorithms to aid in explanations 33 . We propose the addition of mTICI and the number of passes, which are both factors well known to influence outcome 7,8,30,34 and an intuitive reason for their effect on outcomes. That age, mTICI and number of passes a were the features identified as most important by machine learning also gives an intuition that our model is behaving as expected.…”