Abstract WMP9: Impact of Collateral Blood Flow on Clinical Presentation, Diffusion and Perfusion Imaging, Infarct Growth and Clinical Outcome in the DEFUSE 2 Trial

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Objective: To determine the relationships between angiographic collaterals and diffusion/perfusion imaging, subsequent infarct growth and clinical outcomes in DEFUSE 2 study patients. Methods: Patients undergoing endovascular therapy within 12 hours of stroke onset were prospectively enrolled. Only patients with a TICI score of 0, 1 and ICA/M1 occlusion at baseline were included in this analysis. A blinded reader assigned a collateral score using a previously described 5 point scale, from 0 (no collateral flow) to 4 (complete/rapid collaterals to entire ischemic territory). Analysis was dichotomized to poor flow (0-2) versus good flow (3-4). Collateral score was correlated with baseline NIHSS, DWI volume, PWI volume (Tmax > 6), TICI reperfusion, infarct growth and mRS at day 90. Results: Sixty patients had TICI 0, 1 ICA/M1 occlusions and adequate angiographic images to evaluate collaterals. Baseline NIHSS correlated with collateral score (p=0.002). Median NIHSS for patients with poor collateral flow (0-2) was 18 (IQR, 13-22) versus 14 (10-17) for those with good flow (3-4), p=0.025. Baseline T max > 6 volume correlated with collateral score (p=0.002). Median volume of tissue at risk (T max > 6) in those with poor collateral flow was 115 ml (IQR, 74-136) versus 82 (51-109) with good flow, p=0.012. Collateral score did not correlate with baseline DWI volume. TICI reperfusion (0-3) correlated with collateral score (p=0.027). Patients with poor collateral flow had 29% TICI 2b-3 reperfusion versus 65.5% with good flow, p=0.009. Those with poor reperfusion (TICI 0-2a) showed a trend to more infarct growth with poor collaterals, 92 ml (52-194) [mean (IQR)] versus 36 ml (14-106) with good collaterals, p=0.06. Patients with poor collaterals who reperfused (TICI 2b-3) were still likely to have a mRS 0-2 at 90 days compared to those without reperfusion; OR 12 (95% CI, 1.6-98). Conclusion: Collaterals correlate with baseline clinical stroke severity and the PWI volume. In addition, good collaterals correlate with higher rates of reperfusion (TICI 2b-3). When patients do not reperfuse, good collaterals appear to limit infarct growth.