Abstract TP8: Sudden Recanalization: A Game-Changing Factor in Endovascular Treatment of Large Vessel Occlusion Strokes

Abstract

Introduction: First pass recanalization (FPR) is known to be a strong predictor of good outcome in endovascular treatment (EVT) of stroke. The reasons why FPR leads to better outcome than if achieved in multiple-passes (MP) are unknown. We aim to investigate the recanalization pattern and its relation with good outcome. Methods: 609 consecutive patients underwent EVT in the anterior circulation at a single stroke center. Demographic and imaging characteristics, number of passes and recanalization pattern were recorded. Complete recanalization was defined as mTICI2b-3 at the end of EVT. Good functional outcome was defined as modified Rankin scale (mRs) 0-2 at 90 days. Sudden recanalization(SR) was considered when mTICI score varied from 0-1 to 2B-3 in a single pass. Progressive recanalization (PR) was considered if mTICI 2a was achieved at an interim pass before achieving complete recanalization. Patients were categorized as recanalizers at first-pass (FP) and multiple-passes (MP) or non-recanalizers (NR). 70 (10.3%) patients in MP group were excluded due to missing procedural data. Results: 509 (83.9%) patients achieved complete recanalization. SR was achieved in 378 (62.1%) patients; 280 (46%) were FP-SR and 98 (16.1%) were MP-SR. MP-PR was achieved in 131 (21.5%) patients. Rates of good functional outcome depending on recanalization pattern were: FP-SR 57.5%, MP-SR 57.1% (FP-SR vs MP-SR, OR 0.9 CI 0.53-1.54, p=0.7), MP-PR 29.8% (MP-SR vs MP-PR, OR 3.06 CI 1.66-5.62, p<0.001) and NR 17% (MP-PR vs NR, OR 1.23 CI 0.49-3.09, p=0.66). In patients with complete recanalization, univariate analysis showed that both FP (OR 1.91, CI 1.34-2.72, p<0.01) and SR (OR 3.18, CI 2.08-4.87, p<0.01) were associated with good functional outcome. Multivariate analysis showed that SR was a predictor of good functional outcome (OR 3.12, CI 1.9-5.1, p<0.01), being FPR non-significant (OR 1.12, CI 0.66-1.9, p=0.666). Conclusions: Sudden recanalization is a strong predictor of good functional outcome in patients undergoing EVT, even after previous unsuccessful attempts. Progressive recanalization may reflect clot fragmentation and embolization due to more friable composition, leading to worse outcomes. Benefits of first pass effect are driven by sudden recanalization.