Free radical scavenger, edaravone, reduces the brain ischemic damage especially in the white matter

Background Although inflammation and free radicals have been reported to play deteriorative role in the ischemic brain lesion, the effect of free radical scavenger in ischemic stroke patients is still under debate. For exploring the hypothesis that the ischemic damage is reduced by edaravone or not, we evaluated the temporal profile of the size of ischemic stroke lesion assessed by MRI for more than one year following stroke onset, and compared the data between with and without edaravone treated patients. Methods In this hospital, all ischemic stroke patients were treated without edaravone before March 2004, and were basically treated with ederavone after April 2004. Therefore, we sequentially selected the patients who admitted the hospital between April 2003 and March 2004 and were medicated without ederavone as edaravone(-) group (n=79), and the patients who admitted between April 2004 and March 2005 and were treated with edaravone as edaravone(+) group (n=77). To assess the temporal profile of the stroke lesion, we measured the area of stroke lesion on MRI T2WI and calculated the ratio against onset size of stroke lesion on MRI DWI. Then, the observation time was classified into subacute (1-2month after the onset), early chronic (3-6month), late chronic (7-12month) and old (≥13month) stages. Prognosis at 1 year following stroke onset was assessed by using modified Rankin Scale (mRS) based on patients’ clinical records. Results There was no statistical difference of background data between edaravone(-) and (+) groups including age, sex, distribution of stroke type and average lesion size. Reduction of stroke lesion was statistically significant in edaravone(+) group compared to edaravone(-) group in the period of early and late chronic stages (p=0.010 and p=0.007, respectively). Moreover, the decreased rate was significantly abundant in lacunar infarction of edaravone(+) group compared to that of edaravone(-) group in subacute and late chronic stages (p=0.048 and p=0.006, respectively). Edaravone(+) group showed relatively good outcome compared to edaravone(-) group. Conclusion Edaravone may reduce the size of brain ischemic lesion by attenuating the oxidative stress after ischemia. key words: brain infarction; human; acute stroke therapy; clinical prognosis