Safety of intravenous thrombolysis within 4.5 h of symptom onset in patients with negative post-treatment stroke imaging for cerebral infarction

Background Patients with stroke symptoms but negative diffusion-weighted imaging (DWI) might have transient ischemic attacks (TIA) or stroke mimics. Brain DWI is important for the diagnosis of cerebral infarction but it is not available before thrombolysis for most patients to avoid treatment delay. This study aimed to evaluate the safety of IV thrombolysis in patients with a negative post-treatment DWI for cerebral infarction. Methods Weconducted a retrospective study of 89 patients treated with IV recombinant tissue plasminogen activator (rt-PA) within 4.5 h after stroke symptom onset. The patients were identified in our acute stroke registry from January 2009 to September 2010. Information on patients' demographics, clinical characteristics, neuroimaging, treatment complications, and outcomes was obtained and analyzed. Results Out of 89 patients, 23 patients (26%) had a negative DWI on follow-up stroke imaging. Fourteen patients had a TIA and nine patients had a stroke mimic, including Todd's paralysis, complicated migraine, and somatoform disorder. We found significant differences between patients with a positive and a negative DWI in mean age (62 years vs. 52 years; P < 0.01) and median admission NIH stroke scale score (11 points versus 6 points; P < 0.001). Among patients with a positive DWI, four patients had a symptomatic intracerebral hemorrhage (ICH). No patients with a negative DWI had symptomatic or asymptomatic ICH. Conclusions Our results suggest that the administration of IV rt-PA within the first 4.5 h of symptom onset in patients with suspected ischemic stroke is safe even when posttreatment DWI does not demonstrate cerebral infarction.