Background: Previous clinical studies indicated that serum uric acid (UA) level was correlated with better neurologic outcome, and UA might work as an antioxidant against reactive oxygen species, especially in ischemic-reperfusion injury.
Hypothesis: If UA has a neuroprotective function against ischemic-reperfusion injury, serum UA will be recruited and the level will be lowered during the period of acute ischemic stroke after intra-arterial (IA) thrombectomy.
Methods: Among a total of 251 patients who received IA thrombectomy in our hospital from 2005 March to 2015 Aug, we selected the study population according to the following inclusion criteria (N=140): (1) UA level measured within one week after IA thrombectomy; (2) Thrombolysis in Cerebral Infarction perfusion grade (TICI)>0; (3) no recurrence or no severe morbidity or mortality during the acute period. Neurologic severity was assessed via National Institute of Health Stroke Scale (NIHSS), modified Rankin Scale (mRS). The improvement of outcome during admission is assessed via the difference between discharge and admission NIHSS (dNIHSS) scores, and mRS (dmRS) scores. UA consumption ratio was calculated as [(log value of initial serum UA level)- (follow up UA level within 1 week)] / (log value of initial serum UA level).
Results: UA consumption ratio was significantly correlated with discharge mRS in linear regression analysis (R2=0.122, p<0.001). In terms of outcome improvement, UA consumption ratio was also correlated with dmRS (R2=0.033, p =0.03), and dNIHSS (R2=0.08, p =0.0005). When we classified the UA consumption ratio as quintiles, mRS scores at discharge were lower in the highest quintile (OR=0.26, p =0.002), and in the second highest quintile (OR=0.33, p =0.01), than in the lowest quintile. In addition, calculated vessel occlusion time (from admission to hospital and completion of recanalization) was positively correlated with UA consumption ratio(R2=0.05, p =0.04) in patients with outcome improvement (dmRS>0).
Conclusions: In summary, this study showed that UA consumption was associated with better neurologic outcome and also with the vessel occlusion time. These results suggest that serum UA might be used as an endogenous neuroprotective source against ischemia-reperfusion injury.