尿中性粒细胞明胶酶相关脂质运载蛋白在成人心脏手术后急性肾损伤早期诊断中的价值

目的 探讨尿中性粒细胞明胶酶相关脂质运载蛋白（neutrophil gelatinase-associated lipocalin，NGAL）在心脏手术后急性肾损伤（AKI）早期预测和诊断中的价值。 方法 前瞻性收集我院心脏手术患者手术前后不同时相的血、尿标本，选取其中14例AKI患者，分别测定尿NGAL和Scr水平；并选择临床资料相匹配的非AKI患者15例作为对照。观察两组患者围手术期尿NGAL和Scr的动态变化，运用接受者操作特性曲线（ROC）评价尿NGAL诊断AKI的精确性。AKI定义为Scr水平较基础值增加≥50%。 结果 Scr诊断AKI的中位时间为入ICU后24 h（10 h，48 h）。AKI患者术后入ICU即刻的尿NGAL水平显著高于术前基础水平并达峰值20.51（13.42，50.02） μg/L比3.42（1.60，9.92） μg/L，P = 0.006]；也显著高于非AKI患者 2.91（0.72，8.61） μg/L，P = 0.002]。入ICU即刻尿NGAL 的ROC曲线下面积为0.824，95%的可信区间（CI）为0.667~0.980，P = 0.003。当以10.95 μg/L作为诊断截点时，此刻的尿NGAL在AKI诊断中的敏感性和特异性分别为85.7%和80.0%。入ICU即刻的尿NGAL与入ICU 24 h的Scr（r = 0.545，P = 0.002）及eGFR（r = －0.546，P = 0.002)呈正及负相关。 结论 心脏手术后AKI患者术后入ICU即刻的尿NGAL水平显著升高，对诊断AKI具有较高的准确性，其诊断AKI的时间早于Scr。尿NGAL可作为成人心脏术后AKI的早期诊断标志物。

Value of urinary neutrophil gelatinase-associated lipocalin in early diagnosis of acute kidney injury after adult cardiac surgery

Objective To prospectively investigate the value of urinary neutrophil gelatinase-associated lipocalin (NGAL) in the diagnosis of acute kidney injury (AKI) following adult cardiac surgery. Methods Twenty-nine hospitalization patients undergone cardiac surgery were enrolled in the study. Serial blood and urinary samples were collected immediately before incision and at various time intervals after surgery. The primary outcome measure was acute kidney injury, defined as a 50% increase in the level of serum creatinine (Scr) from baseline. Results Fourteen of 29 developed acute kidney injury. The diagnosis time point with Ser was at 24 (10, 48) h after cardiac surgery. By contrast, the concentration of urinary NGAL rose from a median of 3.42(1.60, 9.92) μg/L at baseline to 20.51(13.42, 50.02) μg/L at admission to ICU (P=0.006),and the median concentration of urinary NGAL in patients who developed AKI was significantly higher at admission to ICU compared with patients who did not develop AKI 20.51 (13.42, 50.02) μg/L vs 2.91 (0.72,8.61) μg/L, P=0.002]. As to urinary NGAL at admission to ICU, the area under the receiver-operating characteristic (ROC) curve was 0.824, the sensitivity was 85.7% and the specificity was 80.0% with a cutoff value of 10.95 μg/L. Significant correlation was found between urinary NGAL at admission and the levd of Scr at 24 h in ICU (r=0.545, P=0.002), as well as estimated GFR (r=-0.546,P=0.002). Conclusion Urinary NGAL concentration is significantly higher in patients developing postoperative AKI at the early time of admission to ICU, which may be a useful early biomarker of AKI after adult cardiac surgery.