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Abstract

Introduction: Practice guidelines for treatment of acute ischemic stroke (AIS) recommend fibrinolytic therapy (alteplase [tPA]) in eligible patients dosed at 0.9 mg/kg, maximum 90 mg, based on actual body weight (ABW), but the type of weight (i.e. ABW versus ideal body weight [IBW]) is not specified in any tPA trials. Recent data found trends towards increased rates of hemorrhagic events in patients >100 kg despite the overall lower milligram per kilogram dose. The objectives of this study are to evaluate the differences in patients’ weights, tPA doses, and outcomes in patients dosed based on ABW (hence dosing body weight, DBW) as opposed to IBW. Hypothesis: We hypothesize that large differences exist between patients DBW and IBW and are associated with worse clinical outcomes. Methods: This is a retrospective study evaluating tPA treatment of AIS at a Certified Stroke Center between October 2006 and October 2011. Subjects?18 years with documented AIS and tPA were included. Descriptive statistics, Chi Square and Fisher’s Exact analyses were used as appropriate. Results: There were 98 patients meeting the study criteria. The median difference between patients’ DBW and IBW was 27 kg (±17 kg [range 3 kg to 79 kg]) and the median tPA dose difference between DBW tPA dose and IBW tPA dose was 20 mg (±11 mg [range 0.15 to 45 mg]). The rate of sICH within 36 hours of AIS was 9% (9/98) overall, 0% (0/15) in patients with tPA dose <IBW, 8% (3/37) in patients with a tPA dose >20 mg over IBW dose, and 13% (6/46) in patients with a tPA dose?20 mg over IBW dose (p=NS). The rate of mortality during the initial hospitalization for patients was 9% (9/98) overall, 13% (2/15) in patients with tPA dose <IBW, 5% (2/37) in patients with a tPA dose >20 mg over IBW dose, and 11% (5/46) in patients with a tPA dose?20 mg over IBW dose (p=NS). Conclusions: Large differences exist between patients’ DBW and IBW which resulted in large differences in tPA weight-based doses. The incidence of sICH and mortality was not significantly different between groups stratified by tPA dose difference; however, the sample size was small. Larger studies need to be conducted to determine the appropriate dosing weight based on associations with clinical outcomes.