Abstract 131: MR-based Selection for Endovascular Therapy in Acute Ischemic Stroke With ICA or MCA Occlusion : Propensity Score Matched Analysis From RESCUE-Japan Registry

Abstract

Objective: To identify optimal criteria for MR-based endovascular therapy (EVT) in acute ischemic stroke with the internal carotid artery (ICA) or middle cerebral artery (MCA) occlusion. Materials and methods: From RESCUE-Japan registry, a prospective nation-wide survey of acute ischemic stroke with large vessel occlusion, 996 patients diagnosed with ICA or MCA occlusion by initial MRA and assessed with DWI-ASPECTS were included in the present study. We used a propensity score matching method to create a well-balanced cohort to reduce confounding by indication of EVT. Propensity score was calculated using the following variables: sex, age, initial NIHSS score, Onset-to-Door time, DWI-ASPECTS, occluded site on MRA (categorized into four groups, ICA/proximal M1/distal M1/M2 or distal) and IV-tPA. Favorable outcome defined as modified Rankin Scale of 0 to 2 at 90 days after stroke onset was compared between the propensity score-matched groups. Results: Propensity score matching yielded a well-balanced cohort of 528 patients (264 pairs with and without EVT). In this cohort, there was no significant difference in favorable outcome between the patients with and without EVT (33.7% vs 29.2%, OR 1.25, 95% CI 0.855 - 1.81, p=0.25). However, in the subgroup with ICA/proximal M1 occlusion, the patients with EVT more often achieved favorable outcome than the patients without EVT (33.5% vs 17.7%, OR 2.35, 95% CI 1.41 - 3.97), and there was a significant interaction between the cohorts with ICA/proximal M1 occlusion and distal M1/M2 or distal occlusion (p for interaction < 0.001). Further subgroup investigations showed that this effect was concentrated in the patients with NIHSS of 8 to 29 and DWI-ASPECTS of 4 or more (OR 3.28, 95%CI 1.74 - 6.48, p for interaction=0.066). With respect to Onset-to-Door time, optimal threshold was not obtained. Conclusions: MR-based EVT did not show clinical benefit in the overall study population, but significant increase in favorable outcome in the patients with ICA or proximal M1 segment of MCA occlusion. NIHSS of 8 to 29 and DWI-ASPECTS of 4 or more were thought to be optimal thresholds as additional inclusion criteria.