Background: Acute kidney injury (AKI) is a common post-cardiac surgery complication. It leads to increased morbidity and mortality. The aim of our study is to identify the prevalence and risk factors of AKI and to demonstrate if early postoperative serum cystatin C (sCyC) could accurately predict the development of AKI.Methods: We prospectively studied 628 patients undergoing elective cardiac surgery. Pre-morbid and operative variables known to be or potentially associated with AKI or other adverse outcomes were examined. AKI was defined according to Kidney Disease Improving Global Outcomes (KDIGO) creatinine criteria. Blood samples for biomarker measurement were collected at baseline, within 10 h of surgical completion and daily for three days. Logistic regression was used to assess predictive factors for AKI including 10 h sCyC. Model discrimination was assessed using receiver operator characteristic (ROC) curves.Results: AKI occurred in 178 (28.3%) patients, Stage 1 in 17.5%, Stage 2 in 8.6% and Stage 3 in 2.2%. Mortality rose progressively with increased AKI stage (non-AKI 0.2%, Stage 1 1.8%, Stage 2 11.1% and Stage 3 35.7%). Age > 75 years, baseline estimated glomerular filtration rate (eGFR), proteinuria, diabetes mellitus, hypertension, hyperuricaemia, NYHA classification >2, recent myocardial infarction were associated with AKI in univariate analysis. A multivariate logistic model with clinical factors (age, eGFR, hypertension, NYHA classification >2, combined surgery and operation time) demonstrated moderate discrimination for AKI (area under ROC curve [AUC] 0.75). The 10 h postoperative sCyC levels strongly associated with AKI. After multivariable adjustment, the highest quartile of sCyC was associated with 13.1 - higher odds of AKI, compared with the lowest quartile. Elevated 10 h sCyC levels associated with longer hospital stay, longer intensive care unit stay and duration of mechanical ventilation. The addition of 10 h sCyC improved model discrimination for AKI (AUC 0.81).Conclusions: AKI following cardiac surgery was identified using KDIGO criteria in around one fourth of the patients. These patients had significantly increased morbidity and mortality. When added to prediction model, 10 h sCyC may enhance the identification of patients at higher risk of AKI, providing a readily available prognostic marker.

中文翻译：

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心脏手术后早期血清半胱氨酸蛋白酶抑制剂C增强的急性肾损伤风险预测：一项前瞻性，观察性队列研究。

背景：急性肾损伤（AKI）是心脏手术后常见的并发症。它导致发病率和死亡率增加。本研究的目的是确定AKI的患病率和危险因素，并证明术后早期血清半胱氨酸蛋白酶抑制剂C（sCyC）是否可以准确预测AKI的发展。方法：我们对628例接受择期心脏手术的患者进行了前瞻性研究。检查了已知或潜在与AKI或其他不良结局相关的病前和手术变量。AKI是根据肾脏疾病改善全球预后（KDIGO）肌酐标准定义的。在基线时，手术完成后10小时内以及每天三天收集用于生物标志物测量的血样。Logistic回归用于评估包括10 h sCyC在内的AKI的预测因素。结果：178例（28.3％）患者发生AKI，其中1期占17.5％，2期占8.6％，3期占2.2％。随着AKI阶段的增加，死亡率逐渐上升（非AKI为0.2％，第1阶段为1.8％，第2阶段为11.1％，第3阶段为35.7％）。年龄> 75岁，基线估计肾小球滤过率（eGFR），蛋白尿，糖尿病，高血压，高尿酸血症，NYHA分类> 2，近期心肌梗死与AKI相关。具有临床因素（年龄，eGFR，高血压，NYHA分类> 2，合并手术和手术时间）的多变量logistic模型显示对AKI有中等程度的区分（ROC曲线下的面积[AUC] 0.75）。术后10 h sCyC水平与AKI密切相关。经过多变量调整后，sCyC的最高四分位数与13.1相关-AKI的机率高于最低四分位数。住院时间延长，重症监护病房住院时间延长和机械通气时间延长，导致10 h sCyC水平升高。添加10 h sCyC可以改善AKI的模型辨别力（AUC 0.81）。结论：大约有四分之一的患者使用KDIGO标准确定了心脏手术后的AKI。这些患者的发病率和死亡率显着增加。如果将其添加到预测模型中，则10 h sCyC可能会增强对AKI风险较高的患者的识别，从而提供容易获得的预后指标。住院时间延长，重症监护病房住院时间延长和机械通气时间延长，导致10 h sCyC水平升高。添加10 h sCyC可以改善AKI的模型辨别力（AUC 0.81）。结论：大约有四分之一的患者使用KDIGO标准确定了心脏手术后的AKI。这些患者的发病率和死亡率显着增加。如果将其添加到预测模型中，则10 h sCyC可能会增强对AKI风险较高的患者的识别，从而提供容易获得的预后指标。住院时间延长，重症监护病房住院时间延长和机械通气时间延长，导致10 h sCyC水平升高。添加10 h sCyC可以改善AKI的模型辨别力（AUC 0.81）。结论：大约有四分之一的患者使用KDIGO标准确定了心脏手术后的AKI。这些患者的发病率和死亡率显着增加。如果将其添加到预测模型中，则10 h sCyC可能会增强对AKI风险较高的患者的识别，从而提供容易获得的预后指标。这些患者的发病率和死亡率显着增加。如果将其添加到预测模型中，则10 h sCyC可能会增强对AKI风险较高的患者的识别，从而提供容易获得的预后指标。这些患者的发病率和死亡率显着增加。如果将其添加到预测模型中，则10 h sCyC可能会增强对AKI风险较高的患者的识别，从而提供容易获得的预后指标。