Abstract WP20: Procedure Time and Degree of Collateral Flow Determines Outcome in Acute Endovascular Stroke Therapy

Abstract

BACKGROUND AND PURPOSE: Treatment options for acute ischemic stroke remain limited. There is a clear time dependant nature to this condition, though more evidence is accumulating that degree of collateral flow is a powerful modulator of the effect of time in acute ischemic stroke. In addition, longer procedural times have been associated with worse outcome. We sought to study the relationship between procedure times, collateral flow, recanalization, and clinical outcomes. MATERIALS AND METHODS: A retrospective review of prospectively collected database of 152 patients with anterior circulation strokes treated with endovascular stroke therapy within 8 hours of symptom onset from August 2006 to December 2011. General demographics, clinical features, imaging findings, and outcomes were collected. Univariate and multivariate analysis was performed using JMP statistical analysis software. RESULTS: 152 patients [71 (46.7%) male, mean age: 68±15 years;] were included in the analysis. Complete or partial revascularization occurred in 121 (81%) patients. Collateral circulation was assessed on CTA with 7 (0.6%) having no significant collateral flow, 22 (20.7%) having low collateral flow (50% of affected territory), and 28 (26.4%) having full collateral flow. Overall, there was no significant difference in the baseline clinical and radiographic features between the groups. Analysis of procedural times showed significantly reduced chance of good outcome with procedure times >90 minutes. This effect was more pronounced based on collaterals; in those with good collaterals, good outcome (mRS ≤3) was significantly higher in procedures < 90 minutes (56% vs. 24%; p=0.02); in those with poor collaterals, no good outcomes were seen after 90 minutes of procedure time (39% vs. 0%; p=0.02). CONCLUSION: Procedure time and the degree of collateralization play a significant role in determining outcome in patients who undergo endovascular therapy in acute ischemic stroke, with significantly worse outcomes seen in patients with procedure times >90 minutes, particularly in those with poor collaterals. Treating physicians should keep these factors in mind during the treatment of acute stroke patients.