Frequency of thrombolytic targets in stroke patients presenting in an extended time window

OBJECTIVE: The objective of this study was to determine the proportion of stroke patients presenting in an extended time window who have a thrombolytic treatment target. BACKGROUND: Patients presenting up to 24 h after stroke onset have been found to have penumbral tissue on multimodal imaging. Stroke patients presenting in this extended time window without a large vessel occlusion (LVO) may benefit from reperfusion therapy using thrombolysis. METHODS: Patients seen at our institutions from 2011 through 2015 were reviewed to identify those who presented >4 h and <24 h from last seen normal (LSN) and did not receive acute treatment. Magnetic resonance imaging (MRI) scans were used to dichotomize patients using a diffusion–perfusion mismatch ratio of 1.2. RESULTS: During the study period, 3469 patients were evaluated by our stroke service, with 893 seen 4–24 h from LSN who were not treated. MRI was performed with diffusion and perfusion imaging in 439 patients, of whom 26 were excluded due to hemorrhage and 37 were excluded due to LVO. This left 376 patients who potentially could have been treated with thrombolysis in an extended time window and were included in the analysis. Of these, 156 (42%) demonstrated a mismatch ratio >1.2. Patients with a mismatch presented earlier (P = 0.012), were more likely to be female (P = 0.03), and had higher National Institutes of Health Stroke Scale (P < 0.001). CONCLUSIONS: Almost half of the patients presenting 4–24 h from LSN had a target for thrombolysis in our study. Multimodal imaging may be able to expand the population of treatable stroke patients given the results of recent clinical trials.