胱蛋白酶抑制素C对冠心病合并肾功能不全患者对比剂对早期肾功能影响的研究

Effect of plasma cystatin C for contrast agent for early renal function among patients with coronary artery disease combined with renal dysfunction

目的：评价血浆胱蛋白酶抑制素C（cystatin C,CysC）对于对比剂肾病（contrast Induced Nephropathy,CIN）的早期诊断价值.方法：首先连续入选50例患者采集冠状动脉支架置入术前及术后2,4,8,12及24 h静脉血标本,明确血浆CysC变化趋势,确定最佳样本采集时间.共连续入选拟行冠状动脉造影及支架置入术的患者311例.按照适合中国人的肾脏疾病饮食调整公式计算估测的肾小球滤过率来评价肾功能,入选30＜肾小球滤过率（estinated glomerular filtration rate,eGFR）≤90 mL·min-1·1.73m-2患者.CIN定义为介入治疗术后48～ 72 h SCr水平升高≥44.2 μmol/L（0.5mg/dL）或相对升高≥25％.按照是否发生CIN分成非对比剂肾病组（Non-CIN组,n=272）和对比剂肾病组（CIN组,n=39）.血浆CysC采用酶联免疫吸附试验方法检测,评价血浆CysC升高对CIN的诊断价值.结果：术前血浆CysC浓度与Scr正相关（r=0.340,p＜0.001）.血浆CysC在对比剂暴露后2h开始升高,24h达到高峰,因此术前及术后24h为标本采集时间点.术前及术后24h CysC水平的比较,术后CysC水平在CIN组[术后（554.20±198.69） vs.术前（456.96±136.23） μg/L]和Non-CIN组[术后（468.68±249.92） vs.术前（399.84±182.55） μg/L]均明显升高.以CysC相对升高≥25％为切点,诊断CIN的敏感性和特异性分别为76.9％和81.2％,阴性预测值为96.1％.结论：血浆CysC可作为CIN的早期诊断标志物,其相对升高25％可作为CIN早期诊断的切点,具有较高的阴性预测价值.

Objective：To evaluate plasma Cystatin C （CysC） for early diagnosis of contrast induced nephropathy （CIN）.Methods：Firstly,50 patients were enrolled.The vein blood was obtained before and 2,4,8,24 and 48 hours after procedure for the plasma CysC measure used enzyme-linked immunosorbent assay kit to determine optional time-point for sampling.All the 311 patients were continuously enrolled in study with established or suspected coronary artery disease combined with mild or medium renal dysfunction which was predetermined with the estimated glomerular filtration rate （eGFR） of ＞ 30 mL· min-1 · 1.73m-2 and ≤ 90 mL·min-1· 1.73m-2 according to the formula of modified diet in renal disease.CIN was defined as a relative increase in serum creatinine （SCr） from baseline of ≥ 25％ or an absolute increase of ≥ 0.5 mg/ dL （44μmoL/L） up to day 3.All the patients were arranged to CIN and non-CIN groups according to whether developed CIN or nor.Results：At baseline,the plasma CysC was associated with Scr with 0.340 of r （P ＜ 0.001）.Plasma CysC increased at 2 hour and reached peak at 24 hour after contrast exposure,thus we determine optional time point at 24 hour after procedure for CysC measure.Compared with baseline,the CysC level at 24 hours after procedure increased significantly among CIN [（554.20 ± 198.69）vs.（456.96 ± 136.23） μg/L] as well as among non-CIN [（468.68 ± 249.92） vs.（399.84 ± 182.55） μg/L].The sensitivity and specificity of CysC was 76.9％ and 81.2％ According to cutpoint of relative increasing more than 25％.The negative predictive value was 96.1％.Conclusion：Plasma CysC might be useful biomarker for early diagnosis of CIN with higher negative predictive value.