Is Unexplained Early Neurological Deterioration After Intravenous Thrombolysis Associated With Thrombus Extension?

BACKGROUND AND PURPOSE: Early neurological deterioration (END) after anterior circulation stroke is strongly associated with poor outcome. Apart from straightforward causes, such as intracerebral hemorrhage and malignant edema, the mechanism of END occurring after intravenous thrombolysis remains unclear in most instances. We tested the hypothesis that unexplained END is associated with thrombus extension. METHODS: From our database of consecutively thrombolysed patients, we identified anterior circulation stroke patients who had both admission and 24-hour T2* magnetic resonance imaging, visible occlusion on admission magnetic resonance angiography and no recanalization on 24-hour magnetic resonance angiography. END was defined as ≥4 National Institutes of Health Stroke Scale-point deterioration on 24-hour clinical assessment and unexplained END as END without clear cause. The incidence of susceptibility vessel sign extension on T2* imaging, defined as any new occurrence or extension of susceptibility vessel sign from admission to 24-hour follow-up magnetic resonance, was compared between patients with unexplained END and those without END. RESULTS: Of 120 eligible patients for the present study, 22 experienced unexplained END. Susceptibility vessel sign extension was present in 41 (34%) patients and was significantly more frequent in the unexplained END than in the no-END group (59% versus 29%, respectively; adjusted odds ratio=3.96; 95% confidence interval, 1.25-12.53; P=0.02). CONCLUSIONS: In this study, unexplained END occurring after thrombolysis was independently associated with susceptibility vessel sign extension, suggesting in situ thrombus extension or re-embolization. These findings strengthen the need to further investigate early post-thrombolysis administration of antithrombotics to reduce the risk of this ominous clinical event.