Interaction of Recanalization, Intracerebral Hemorrhage, and Cerebral Edema After Intravenous Thrombolysis

BACKGROUND AND PURPOSE: Both intracerebral hemorrhage (ICH) and brain edema have been attributed to reperfusion after intravenous thrombolysis. We explored the interaction of recanalization and core size for imaging outcomes (ICH and vasogenic brain edema). METHODS: In patients with anterior circulation occlusion given intravenous thrombolysis <4.5 hours and imaged with computed tomographic (CT) perfusion and CT angiography, we defined volumes of core (relative delay time >2 s and relative cerebral blood flow <40%) and penumbra (relative delay time >2 s). CT and CT angiography at 24 hours were reviewed for ICH (European Cooperative Acute Stroke Study [ECASS]-2 definition), early vasogenic edema (third International Stroke Trial [IST-3] criteria), and recanalization (thrombolysis in myocardial infarction 2-3). Independent effects of recanalization, core volume and potential interactions on edema, ICH and day 90 outcomes were estimated by logistic regression. RESULTS: In 123 patients, there was a trend for recanalization to be associated with H1/2 ICH (odds ratio [OR], 2.3 [0.97-5.5]; P=0.06) but not with PH1/2 ICH (OR, 1.7 [0.33-8.8]; P=0.5), any edema, or significant brain edema (OR, 1.45 [0.4-4.9]; P=0.55). Ischemic core (>50 mL) was associated with any ICH (OR, 4.0 [1.6-9.5]; P=0.003), edema (OR, 5.4 [2-14]; P<0.01), and significant brain edema (OR, 17.4 [5.3-57]; P<0.01) but not with PH1/2 ICH (OR, 1.2 [0.23-6.5]; P=0.8), after controlling for recanalization. There was no significant interaction of recanalization and large core for any adverse outcomes. CONCLUSIONS: Large ischemic core was associated with poorer outcomes and both early vasogenic brain edema and ICH, but recanalization on 24-hour CT angiography was associated with clinically favorable outcome. There was no significant interaction of recanalization and large core volume for any outcomes. The association of hemorrhage or brain edema with post-thrombolysis reperfusion is unclear.