Abstract 105: Iodinated Contrast Does Not Alter Clotting Dynamics in Acute Ischemic Stroke as Measured by Thromboelastography

Abstract

Introduction: Modern treatment of acute ischemic stroke (AIS) has increasingly incorporated multimodal CT imaging. Data illustrating that radiographic contrast agents alter fibrin fiber characteristics and decrease fibrinolysis by thrombolytic agents are potentially concerning. Thromboelastography (TEG) provides an integrated, dynamic view of coagulation and has recently been correlated with thrombolysis in AIS patients. This is the first study to examine the effects of contrast agents on tPA-induced clot lysis using TEG. We hypothesized that receiving computed tomography angiography (CTA) prior to tPA will impair thrombolysis as measured by TEG. Methods: AIS patients receiving 0.9 mg/kg tPA within 4.5 hours of symptom onset were enrolled. For CTA, iohexol dose was calculated using Medrad’s P3T software. Blood was drawn for TEG prior to CTA or tPA treatment and again 10-minutes after tPA bolus. TEG values, time of TEG draw and tPA administration, and CTA times were recorded. TEG values in patients having CTA prior to tPA were compared with patients in whom a CTA was performed either after tPA or not at all. Results were analyzed using Mann-Whitney U Test. Results: 100 AIS patients received tPA. Of these, 17 patients had CTA prior to TEG blood draws and tPA bolus. 57 patients had either CTA following tPA or no CTA. The median change in clot lysis (LY30) following tPA was 94.8% in the contrast group vs. 94.5% in controls (p = 0.84). The median reduction in clot strength (G) was -8.8 dyn/cm 2 in the contrast group vs. -8.6 dyn/cm 2 in controls (p = 0.51). Pre-tPA G appeared to be attenuated by contrast (7.7 vs. 5.9 dyn/cm 2 ) when corrected for platelet activity; however, this difference was not significant (p = 0.14). There was no effect of contrast on any other pre-tPA TEG value. Conclusion: The current data do not support any impairment of tPA-induced clot lysis by contrast agents. Baseline TEG also appears to be unaffected by contrast, but more patients are needed to better examine a possible interaction between clot strength and contrast agents.