Admission Motor Strength Grade Predicts Mortality in Patients with Acute Ischemic Stroke Undergoing Mechanical Thrombectomy

Abstract

Introduction: The mortality due to mechanical thrombectomy (MT) in the acute treatment of intracranial arterial thromboses can be up to 30%. It is important to determine pre-procedural factors that help predict post-intervention prognosis. Hypothesis: To determine which factors on admission may be used to predict mortality after MT. Methods: Retrospective analysis of 62 patients who underwent MT for acute ischemic stroke with or without concurrent intravenous thrombolysis from an IRB approved stroke database (Jan07-Mar11). Mortality served as an independent primary outcome measure using five baseline variables: medical research council (MRC) motor grade (0-5); modified collateral flow (CS) grading (0-3); age; and acute and chronic co-morbidities in the univariate and multivariate analyses. If upper and lower extremity motor grade differed, the lower score was utilized. Age was analyzed independently as well as dichotomized using 80 as cut-off value. Relevant stroke related acute and chronic co-morbidities were given 1 point each and mean calculated. Results (table): In the univariate analysis, low MRC (0-1) motor strength grade (p=0.001) and age (p=0.011) was significantly associated with mortality. The presence of collateral flow or acute and chronic co-morbidities were not significantly associated with mortality. In the multivariate analysis, motor grade retained its statistical significance for mortality (p=0.003) along with chronic co-morbidities (p=0.04). Interestingly, age which was a strong predictor of favorable stroke outcome in previous studies was not statistically significant for predicting mortality (p=0.32). Conclusions: In conclusion, admission MRC motor strength grade may serve as a robust predictor of mortality after MT in patients with acute ischemic stroke. Further validation by prospective multivariate analysis using larger sample size is needed.