Abstract: Objective  To observe the value of complement component 3a receptor (C3AR1) in evaluating the efficacy and prognosis of high-dose atorvastatin combined with dual antiplatelet therapy (DAPT) in the treatment of acute cerebral infarction (ACI). 
Methods  In total, 60 patients with ACI treated in the hospital were selected as the observation group, and 60 healthy people undergoing physical examination in the hospital during the same period were selected as the control group. The observation group was randomly divided into routine-dose group and high-dose group, with 30 cases in each group. Reverse transcription polymerase chain reaction (RT-PCR) was used to detect the difference of serum C3AR1 gene expression between the two groups before treatment and at 1, 2 and 4 weeks after treatment. The number of carotid plaques (or soft plaques) and carotid intima-media thickness (IMT) of patients were measured. In the meantime, National Institute of Health Stroke Scale (NIHSS) score, score of Activity of Daily Living Scale (ADL), modified Rankin Scale score (mRS), hypersensitive C-reactive protein (hs-CRP) and blood lipids ［total cholesterol (TC), triglyceride (TG), high-density lipoprotein cholesterol (HDL-C), low-density lipoprotein cholesterol (LDL-C)］ were evaluated. The correlation between C3AR1 and the above indexes was analyzed by Pearson method. 
Results  The relative expression of C3AR1 mRNA in the observation group was higher than that in the control group (P＜0.05). The number of carotid plaques (or soft plaques), IMT, NIHSS score, ADL score, mRS score, hs-CRP level, TC, TG, HDL-C and LDL-C levels and the relative expression of C3AR1 mRNA in both groups were decreased with the prolongation of treatment time, and the decrease was smaller in the high-dose group than in the routine-dose group; there was no significant difference in IMT, TC, TG and LDL-C between time-points and interaction between groups (P＞0.05), and there were significant differences in other indicators between groups, time points and time points between groups (P＜0.05). Results Bivariate Pearson correlation analysis showed that, the relative expression of C3AR1 mRNA before treatment was not correlated with the number of carotid plaques (or soft plaques), IMT, NIHSS score, ADL score, mRS score, hs-CRP level, TC, TG, HDL-C and LDL-C level in patients with ACI (P＞0.05). At 1, 2 and 4 weeks after treatment, the relative expression of C3AR1 mRNA was positively correlated with the number of carotid plaques (or soft plaques), IMT, NIHSS score, ADL score, mRS score, hs-CRP level, TC, TG, HDL-C and LDL-C level in patients with ACI (P＜0.05). 
Conclusion  The detection of C3AR1 can be used to evaluate the efficacy and prognosis of high-dose atorvastatin combined with dual antiplatelet therapy in the treatment of ACI. 

Key words: cerebral infarction, complement component 3a receptor, atorvastatin