胱抑素C对对比剂肾病的预测价值

目的探讨冠状动脉内应用对比剂后肌酐（SCr）及胱抑素C（Cystatin C，CysC）水平的变化，评价CysC对对比剂肾病（contrast induced nephropathy，CIN）的预测价值。方法选择于我院进行冠状动脉造影和（或）介入治疗的冠心病患者，监测介入术前、术后1天、2天、3天SCr和CysC水平，采用MDRD公式计算肾小球滤过率（（eGFR））。主要终点事件是CIN的发生。结果共纳入384例患者，以SCr作为诊断标准，16例(4.17%)患者发生CIN。介入术后第1天、第2天、第3天CysC浓度较术前升高（均P＜0.05）。CysC与SCr呈正相关（r=0.313，P＜0.01），CysC与eGFR呈负相关（r=-0.325，P＜0.01）。术后第2天CysC诊断CIN的ROC曲线下面积为0.833（95%CI=0.744～0.992，P＜0.01），优于术后第1天和术后第3天，最佳分界点为1.115 mg/L。对术后第2天CysC水平不同升高程度做ROC曲线，得出ROC曲线下面积为0.812（95%CI=0.802～0.822，P＜0.01），最佳分界点为12.5%。结论CysC能够较早的评估肾功能状态，是一个能够反应CIN的敏感指标；术后第2天CysC水平诊断CIN的准确性优于术后第1天和第3天，其升高≥12.5%可以作为诊断CIN的切点。

Predictive value of serum cystatin C in early evaluation of contrast induced nephropathy

Objective To evaluate of cystatin C (CysC) on the predictive value of contrast induced nephropathy(CIN) by comparing the changes of creatinine(SCr) and CysC after coronary arteriography (CAG).Methods Patients who underwent coronary angiography and/or percutaneous coronary intervention were enrolled. Serum creatinine and CysC were monitored before angiography， 1 day， 2 days， 3 days after angiography. Glomerular filtration rate was estimated by MDRD. The primary end point was the incidence of CIN. Results A total of 384 patients were enrolled in this study， and 16 (4.17%) patients developed CIN according to the SCr criteria. Serum CysC was significantly higher at 1 day， 2 days，3 days after angiography (P＜0.05). The level of serum CysC was positively correlated with SCr level (r=0.313，P<0.01)， but negatively correlated with eGFR (r=-0.325，P<0.01). The area under ROC curve at 2 days after angiography was 0.833（95%CI=0.744 0.992，P＜0.01）， better than 1 day and 3 days after angiography. The best cutoff point was 1.115 mg/L. The area under ROC curve of varying degrees at 2 days after angiography was 0.812（95%CI=0.802 0.822，P＜0.01） and the best cutoff point was 12.5%. Conclusion As serum CysC could evaluate the renal function at early period，it could be a sensitive biomarker to evaluate induced CIN. The accuracy of diagnosis CIN in CysC level 2 days after CAG was higher than that 1 day and 3 days after CAG. Moreover， ≥12.5% increase can be used as a cutoff point in CIN diagnosis.