Abstract T P187: How High Is Too High? An Analysis of the Upper Threshold for Serum FVIII in Ischemic Stroke

Background: Elevated factor VIII (FVIII) is an independent risk factor for thromboembolic events and acute ischemic stroke (AIS). Laboratory reference ranges categorize levels u003e150% and u003e200% activity as elevated and severely elevated, respectively. We sought to identify the upper limit of FVIII activity with the most clinical relevance for outcomes after AIS. Methods: From our stroke registry, patients admitted with AIS between 07/2008 to 10/2013 were included if FVIII levels were measured during admission. Logistic regression, was used to assess differences in baseline, in-hospital, and outcome variables in patients with FVIII elevation as compared to those with normal levels. The primary outcome was poor modified Rankin Scale (mRS) score on discharge, defined as mRSu003e2. Serial dichotomized FVIII levels using a 5-point incremental analysis of levels were analyzed with respect to poor outcome. The threshold yielding the largest area under the curve (AUC) was determined. Results: Among 1,453 cases in our r...