Abstract 189: ADAMTS13 Activity Predicts Response to Thrombolysis in the Acute Stroke Setting

INTRODUCTION: Biological markers predicting tPA response in acute stroke could be used for dose adjustments or early selection of patients for endovascular procedures. ADAMTS13 (A Disintegrin And Metalloproteinase with a ThromboSpondin type 1 motif, member 13) inactivates Von Willebrand Factor by cleaving it, and its deficiency may generate prothrombotic diseases such as thrombotic thrombocytopenic purpura. We aimed to analyze ADAMTS13 activity in acute stroke patients and its relation to vessel patency among those treated with intravenous tPA. METHODS: Acute ischemic stroke patients (n=104) with documented arterial occlusion by transcranial Doppler (TCD), who received tPA within the first 4.5 hours after symptoms onset were recruited and compared with 38 age-matched healthy subjects. Samples were collected at baseline, before thrombolytic treatment, and ADAMTS13 activity was measured by ELISA and expressed as %. A temporal profile of ADAMTS13 activity was determined at 24 hours and 3 months in a subset of 10 patients. Recanalization was assessed 2 hours after tPA bolus by TCD, using thrombolysis in brain ischemia (TIBI) flow grading system. Logistic regression analysis was conducted to determine independent predictors of 2-hour recanalization in patients with proximal arterial occlusions. RESULTS: ADAMTS13 activity was consistently lower in stroke patients than in healthy controls (p74.72% was an independent predictor of recanalization [OR=5.148 (1.463-18.111), p=0.011], together with early ischemic signs at baseline neuroimaging [OR=0.065 (0.006-0.712), p=0.025] and OCSP classification (TACI vs. PACI) [OR=0.072 (0.011-0.45), p=0.005]. CONCLUSIONS: In stroke patients treated with tPA, ADAMTS13 activity may be used to monitor the treatment as well as to make decisions regarding more aggressive reperfusion therapies when the absence of a response to intravenous tPA is anticipated.