Abstract WMP89: Comparative Outcome Of Patients With And Without Mild Pre-Stroke Morbidity Following Endovascular Treatment - Results From The Hermes Meta-analysis

Abstract

Introduction: Analyses of the effect of prestroke functional levels upon outcome of endovascular therapy (EVT) have focused on the course of patients with moderate to substantial prestroke disability. The effect of complete freedom from pre-existing disability (modified Rankin Scale [mRS]=0) vs. predominantly mild pre-existing disability (mRS≥1) has not been well delineated. Methods: Data were from the HERMES collaboration, a meta-analysis of 7 randomized controlled trials that tested the safety and efficacy of EVT. Two multivariable ordinal logistic regression models were used to compare the association between EVT and 90-day mRS (primary outcome) in patients who were asymptomatic prestroke (mRS=0) and those who had predominantly mild disability prestroke (mRS≥1). Secondary outcomes included successful reperfusion (in the EVT subgroup) and symptomatic intracranial hemorrhage (sICH) at 24 hours. Results: We included 1764 patients in the analysis, of whom 223 (12.6%) had a prestroke mRS≥1 (162 mRS 1, 61 mRS≥2). Patients with prestroke mRS≥1 had worse outcomes compared to those with prestroke mRS=0 (adjusted odds ratio [aOR] 0.42 (95%CI:0.28-0.63). Nonetheless, a significant benefit of EVT was observed in the mRS≥1 subgroup (common OR:1.79 (95%CI:1.11-2.89, Figure). No significant differences were observed with regards to rates of reperfusion (aOR:0.91, 95%CI:0.52-1.57) and sICH (aOR:1.03, 95%CI:0.37-2.93) between patients asymptomatic vs. predominantly with mild disability prestroke. Conclusion: Patients completely asymptomatic prior to onset have better outcomes from EVT than those with mild disability. Patients with prestroke mRS=1 still do more often achieve good functional outcomes with EVT compared to conservative management, with similar rates of reperfusion and sICH. These findings indicate even mild pre-existing symptoms exert prognostic (outcome) but not predictive (different response to therapy) in patients eligible for EVT.