Abstract: Objective To investigate the relationship between serum cystatin C (Cys C) and the degree of coronary artery disease in the elderly patients with acute coronary syndrome (ACS). Methods A total of 246 patients with ACS confirmed by coronary angiography were selected as the observation group, and 38 patients without coronary heart disease excluded by coronary angiography during the same period were selected as the control group. The level of serum Cys C in all the patients was detected within 24 hours, and the correlation between the level of serum Cys C and Gensini score in the patients with ACS was analyzed. Results With the increase of the degree of coronary lesion, the level of serum Cys C increased gradually, and there were statistical differences among different groups (P < 0.01). The level of serum Cys C was positively correlated with Gensini score in the patients with ACS (r=0.436, P<0.05). Logistic regression model and multiple linear regression model showed that the level of serum Cys C was an risk factor for ACS and Gensini score (OR=1.843, B=5.076,all P < 0.05). Receiver operating characteristic curve showed that Cys C could predict the incidence of ACS with a critical value of 8.35 mg/dL, with sensitivity of 0.683, specificity of 0.763. Conclusions The level of serum Cys C in the patients with ACS is related to the severity of coronary artery disease, which is a risk factor for the aggravation of coronary artery disease.

Key words: acute coronary syndrome, cystatin C, Gensini score