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 >150% and >200% 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 mRS>2. 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 registry, inclusion criteria were met for 267 patients. In our sample, in a comparison of normal FVIII levels vs. elevation >150%, and elevation >200%, patients differed significantly according to race (p=0.0017), history of diabetes (p=0.0001), and history of congestive heart failure (p=0.0401). FVIII elevation threshold of 150% was the best predictor of poor mRS on discharge (OR 3.7, 95% CI 1.77-8.05, p=0.0006) with an AUC of 0.618.
Conclusions: FVIII elevation greater than 150% is the most clinically useful threshold for the prediction of poor clinical outcomes in the setting of AIS based on data from our center.
Author Disclosures: A.A. Samai: None. A.K. Boehme: None. D.J. Monlezun: None. A. George: None. L. Dowell: None. C. Leissinger: None. L. Schluter: None. R. El Khoury: None. S. Martin-Schild: Research Grant; Modest; Pilot Grant from Tulane University School of Medicine.
- © 2015 by American Heart Association, Inc.