Does the application of X-ray contrast agents impair the clinical effect of intravenous recombinant tissue-type plasminogen activator in acute ischemic stroke patients?

BACKGROUND AND PURPOSE Experimental data suggest a negative interaction between x-ray contrast agents and fibrinolytic efficacy of recombinant tissue-type plasminogen activator (rtPA). We hypothesized that the application of a contrast agent before intravenous thrombolysis with rtPA reduces its clinical efficacy in acute ischemic stroke. METHODS We retrospectively studied consecutive ischemic stroke patients receiving contrast agents for computed tomography angiography before intravenous treatment with rtPA. We compared functional outcomes with an historical control group from the Canadian Alteplase for Stroke Effectiveness Study who did not receive contrast agents before thrombolysis with rtPA. Primary end point was favorable functional outcome at 90 days defined as modified Rankin Scale scores 0 to 2. We performed logistic regression analysis and a propensity score matching analysis to estimate the effect size of contrast agent use as a negative predictor of outcome. RESULTS We identified 111 patients for the computed tomography angiography and 1119 patients for the control group. Proportions of favorable functional outcome were 47.7% (53/111 patients) for the computed tomography angiography group and 49.5% (542/1094 patients) for the control group (P=0.77). Adjusted probabilities for favorable outcome were 0.48 (95% CI, 0.37-0.58) and 0.51 (95% CI, 0.47-0.54), respectively. Contrast use was associated with reduced odds of favorable outcome (OR, 0.62(;) 95% CI, 0.38-0.99). Propensity score matching suggested a larger effect size (OR, 10.0%; 95% CI, 0.5%-19.3%). CONCLUSIONS Our study did not show a significant negative clinical effect of x-ray contrast agents applied before intravenous thrombolysis with rtPA. However, to confirm a possible small negative interaction between contrast agents and rtPA, additional experimental and prospective clinical studies are needed.