Abstract 169: IV t-PA May Result in Better Outcomes than Conservative Care in Patients with Mild Acute Ischemic Stroke and Large Vessel Occlusion

Abstract

Introduction: Most patients with mild acute ischemic stroke (AIS) symptoms are excluded from acute stroke therapy (AST). Studies have shown that patients presenting with large vessel occlusions (LVO) and low NIH stroke scale (NIHSS) may have poorer outcomes than previously presumed. The optimal treatment strategy in this population is unknown. Methods: A retrospective chart review of patients with AIS presenting to our tertiary care center between 2010 and 2013 was carried out. Inclusion criteria included LVO as cause of AIS and initial NIHSS < 8. Patients presenting >24 hours after last known normal were excluded. Patient demographics, administered therapies and short-term clinical outcomes were analyzed. For patients lost to follow up, last known values were imputed. Favorable 30-day outcomes were defined as mRS 2, NIHSS 1 or at least 4 point decrease in NIHSS. Results: A total of 121 patients (56.19% males; mean age 63.85±14.08) met inclusion criteria. Anterior circulation was involved in 69.4% cases [MCA (46.28%), ICA (16.52%), ACA (2.47%), ICA-MCA (4.13%)] vs 33.88% posterior circulation cases [PCA (8.26%), Ba (5.7%), V (19%)]. Median admission NIHSS and pre-admission mRS were 4 & 0 respectively, which were statistically significant predictors of favorable outcome. Only 23 patients (19%) received AST [IV t-PA: 13, intrarterial (IA) therapy: 6, IV + IA: 4]. AST patients had shorter time from onset of symptoms to evaluation (mean: 3.7 vs. 9.9 hours, p < 0.001), higher NIHSS on arrival (median: 5 vs. 3, p = 0.024), and were more likely to have a history of stroke (39% vs. 18%, p = 0.049). The odds of a 30-day favorable mRS were 1.7 times higher in the treated group, although not statistically significant (95% CI: 0.58, 5.7; p = 0.333). Numbers in the subgroup analysis remained too small to reach statistical significance, but 85% of patients who received IV t-PA (and 70% with any treatment) had a favorable 30-day outcome versus 62% of patients with conservative care.Conclusion: Our study suggests that qualifying patients with LVO and mild AIS presenting early may have better outcomes if treated with IV t-PA. We propose that rapid evaluation of vessel status may support more aggressive treatment considerations in patients with mild AIS. Further prospective data is needed.