Abstract 6: Results From the DEFUSE 3 Trial: Good Leptomeningeal Collaterals Are Associated With Reduced Core Infarct Size but Not Improved Neurologic Outcome

Abstract

Introduction: The role of collaterals for acute ischemic stroke patients who qualify for endovascular thrombectomy (EVT) in the late therapeutic window (>6 hours from last known normal) remains unknown. We hypothesize that good collaterals on CT angiography (CTA) will moderate neurologic outcome and the effect of EVT. Methods: This is a prespecified analysis of DEFUSE 3. The primary outcome is functional independence (modified Rankin scale ≤2). Additional outcomes include baseline infarct volume, change from baseline in the infarct volume at 24 hours, and death at 90 days. Results: Of 130 patients, 33 (25%) had poor and 97 (75%) had good collaterals. There was no difference in the rate of functional independence with good versus poor collaterals (30% vs. 39%, p=0.3), but good collaterals were associated with significantly smaller infarct volume and less infarct growth. The difference in the treatment effect of EVT between good versus poor collaterals was not significant (p=0.8). Collateral status did not affect the rate of death [19% vs. 24%, p=0.5]. Conclusion: In DEFUSE 3 patients, good leptomeningeal collaterals on CTA were not predictive of functional independence or death. These findings introduce the possibility that CTA collaterals may not have a causal relationship with neurologic outcome for anterior circulation large vessel occlusion patients with Target Mismatch in the late window.