Abstract P468: Functional Outcome of Patients Undergoing Mechanical Thrombectomy Outside of the Dawn and Defuse Criteria

Background: The DAWN and DEFUSE trials (D&D) extended the mechanical thrombectomy (MT) window to 16-24 hours from last known normal (LKN) in patients with internal carotid artery (ICA) or proximal middle cerebral artery (M1) large vessel occlusions (LVO), with limits on core infarct and penumbra size. With advances in imaging and procedural techniques, many have extended these results to patients outside of the study criteria, yet there is limited analysis of outcomes in those receiving MT beyond these guidelines. This study evaluates the functional outcome of MT in acute stroke patients presenting within 24 hours of LKN outside of the D&D criteria vs those meeting study criteria at a single Comprehensive Stroke Center. Methods: An IRB approved study was performed in which consecutive anterior circulation ischemic stroke patients presenting to Wake Forest Baptist Health from 12/1/18-12/31/19 within 0-24 hours of LKN were retrospectively studied. Patients were grouped by eligibility for DAWN or DEFUSE (mRS ≦1, ICA/M1 occlusion, age 15, and mismatch ratio >1.8) or neither. Good outcome was defined as mRS ≦3 within 3 months of discharge. If not available, discharge mRS was used. A multivariate logistic regression model analyzed the outcome controlling for confounding factors. Results: Of 130 patients, 57 (44%) fell outside D&D criteria. There was no significant difference between age, rate of IV tPA, admission NIHSS, baseline co-morbidities, or core infarct size between groups. Median mismatch volume was greater in the D&D group compared to patients in the non D&D group (97cc, IQR 67-146 vs 67cc, IQR 30-111; p=0.002). Good outcome was seen in 34 (47%) D&D patients vs 30 (53%) in the non D&D group; controlling for confounding factors affecting 3 month mRS (age, NIHSS, time to revascularization, atrial fibrillation, prior stroke), this was not statistically significant (p=0.25). Conclusion: The outcome of MT in patients with anterior circulation LVO is not different between those meeting and not meeting D&D criteria. MT should be considered in patients presenting within 24 hours outside study guidelines.