Abstract WP44: Less Infarct Volume Growth in Early Window Mechanical Thrombectomy Compared to Late Window in Emergent Large Vessel Occlusion

Abstract

Background: While clearly beneficial based on outcome analysis, there has been limited data regarding prevention of further infarct growth in late (6-24 hour) compared to the early window (<6 hour) mechanical thrombectomy (MT). More expedient revascularization in the early group prevents further growth, but the presence of good collaterals in late window patients may prevent infarct progression over time. The aim of this study is to compare infarct growth between early and late window intervention. Methods: We reviewed consecutive patients presenting to a comprehensive stroke center from January 2016 to December 2018 with emergent large vessel occlusion (ELVO) undergoing MT. Standard protocol included pre-procedural MRI imaging and only those with post-procedural MRI were included. Patients were divided into early (<6 hour from onset to arterial puncture) and late (6-24 hour from onset to arterial puncture) groups. Infarct volume on MRI was measured using region of interest analysis by investigators blinded to group. MRI growth between pre- and post- MT MRI was compared using both absolute difference (post minus pre volume) and ratio (pre:post volume). Results: Among 117 patients meeting inclusion criteria, 40 (34.2%) patients had early and 77 (65.8%) late interventions. Those in the early group showed a trend toward lower infarct volume growth compared to those in the late group (16.0 +/- 42.9 vs 31.4 +/- 60.9 mL growth, p = 0.16). Ratios of pre to post MT infarct volume was significantly different in early and late intervention group (1.07 +/- 1.6 vs 0.63 +/- 0.33, p = 0.02), signifying less infarct growth in the early group. Conclusion: In patients with ELVO for whom MT was performed, there was less infarct growth in the early time window compared to the late window.