Presurgical serum cystatin C and risk of acute kidney injury after cardiac surgery.

Acute kidney injury (AKI) after cardiac surgery is associated with poor outcomes, but is challenging to predict from information available before surgery. Prospective cohort study. The TRIBE-AKI (Translational Research Investigating Biomarker Endpoints in Acute Kidney Injury) Consortium enrolled 1,147 adults undergoing cardiac surgery at 6 hospitals from 2007-2009; participants were selected for high AKI risk. Presurgical values for cystatin C, creatinine, and creatinine-based estimated glomerular filtration rate (eGFR) were categorized into quintiles and grouped as "best" (quintiles 1-2), "intermediate" (quintiles 3-4), and "worst" (quintile 5) kidney function. The primary outcome was AKI Network (AKIN) stage 1 or higher; ≥0.3 mg/dL or 50% increase in creatinine level. Analyses were adjusted for characteristics used clinically for presurgical risk stratification. Average age was 71 ± 10 years (mean ± standard deviation); serum creatinine, 1.1 ± 0.3 mg/dL; eGFR-Cr, 74 ± 9 mL/min/1.73 m(2); and cystatin C, 0.9 ± 0.3 mg/L. 407 (36%) participants developed AKI during hospitalization. Adjusted odds ratios for intermediate and worst kidney function by cystatin C were 1.9 (95% CI, 1.4-2.7) and 4.8 (95% CI, 2.9-7.7) compared with 1.2 (95% CI, 0.9-1.7) and 1.8 (95% CI, 1.2-2.6) for creatinine and 1.0 (95% CI, 0.7-1.4) and 1.7 (95% CI, 1.1-2.3) for eGFR-Cr categories, respectively. After adjustment for clinical predictors, the C statistic to predict AKI was 0.70 without kidney markers, 0.69 with creatinine, and 0.72 with cystatin C. Cystatin C also substantially improved AKI risk classification compared with creatinine, based on a net reclassification index of 0.21 (P < 0.001). The ability of these kidney biomarkers to predict risk of dialysis-requiring AKI or death could not be assessed reliably in our study because of a small number of patients with either outcome. Presurgical cystatin C is better than creatinine or creatinine-based eGFR at forecasting the risk of AKI after cardiac surgery.

Shlipak MG ，Coca SG ，Wang Z ，Devarajan P ，Koyner JL ，Patel UD ，Thiessen-Philbrook H ，Garg AX ，Parikh CR ，TRIBE-AKI Consortium ... -  《-》

Preoperative serum cystatin C combined with dipstick proteinuria predicts acute kidney injury after cardiac surgery.

Wang X ，Che M ，Xie B ，Xue S ，Yan Y ... -  《-》

Serum cystatin C- versus creatinine-based definitions of acute kidney injury following cardiac surgery: a prospective cohort study.

The primary aim of this study was to compare the sensitivity and rapidity of acute kidney injury (AKI) detection by cystatin C level relative to creatinine level after cardiac surgery. Prospective cohort study. 1,150 high-risk adult cardiac surgery patients in the TRIBE-AKI (Translational Research Investigating Biomarker Endpoints for Acute Kidney Injury) Consortium. Changes in serum creatinine and cystatin C levels. Postsurgical incidence of AKI. Serum creatinine and cystatin C were measured at the preoperative visit and daily on postoperative days 1-5. To allow comparisons between changes in creatinine and cystatin C levels, AKI end points were defined by the relative increases in each marker from baseline (25%, 50%, and 100%) and the incidence of AKI was compared based on each marker. Secondary aims were to compare clinical outcomes among patients defined as having AKI by cystatin C and/or creatinine levels. Overall, serum creatinine level detected more cases of AKI than cystatin C level: 35% developed a ≥25% increase in serum creatinine level, whereas only 23% had a ≥25% increase in cystatin C level (P < 0.001). Creatinine level also had higher proportions meeting the 50% (14% and 8%; P < 0.001) and 100% (4% and 2%; P = 0.005) thresholds for AKI diagnosis. Clinical outcomes generally were not statistically different for AKI cases detected by creatinine or cystatin C level. However, for each AKI threshold, patients with AKI confirmed by both markers had a significantly higher risk of the combined mortality/dialysis outcome compared with patients with AKI detected by creatinine level alone (P = 0.002). There were few adverse clinical outcomes, limiting our ability to detect differences in outcomes between subgroups of patients based on their definitions of AKI. In this large multicenter study, we found that cystatin C level was less sensitive for AKI detection than creatinine level. However, confirmation by cystatin C level appeared to identify a subset of patients with AKI with a substantially higher risk of adverse outcomes.

Spahillari A ，Parikh CR ，Sint K ，Koyner JL ，Patel UD ，Edelstein CL ，Passik CS ，Thiessen-Philbrook H ，Swaminathan M ，Shlipak MG ，TRIBE-AKI Consortium ... -  《-》

Urinary cystatin C and acute kidney injury after cardiac surgery.

Acute kidney injury (AKI) is common after cardiac surgery and is associated with adverse patient outcomes. Urinary cystatin C (CysC) level is a biomarker of proximal tubule function and may increase earlier in AKI than serum creatinine level. Prospective cohort study. The TRIBE AKI (Translational Research Investigating Biomarker Endpoints in AKI) Consortium prospectively enrolled 1,203 adults and 299 children and adolescents at 8 institutions in 2007-2009. Urinary CysC (in milligrams per liter) within the first 12 hours after surgery. Serum creatinine-based AKI was defined as AKI Network stage 1 (mild AKI) and doubling of serum creatinine from the preoperative value or need for dialysis during hospitalization (severe AKI). Analyses were adjusted for characteristics used clinically for AKI risk stratification, including age, sex, race, estimated glomerular filtration rate, diabetes, hypertension, heart failure, nonelective surgery, cardiac catheterization within 72 hours, type of surgery, myocardial infarction, and cardiopulmonary bypass time longer than 120 minutes. Urinary CysC level measured in the early postoperative period (0-6 and 6-12 hours postoperatively) correlated with both mild and severe AKI in adults and children. However, after analyses were adjusted for other factors, the effect was attenuated for both forms of AKI in both cohorts. Limited numbers of patients with severe AKI and in-hospital dialysis treatment. Urinary CysC values are not associated significantly with the development of AKI after cardiac surgery in adults and children.

Koyner JL ，Garg AX ，Shlipak MG ，Patel UD ，Sint K ，Hong K ，Devarajan P ，Edelstein CL ，Zappitelli M ，Thiessen-Philbrook H ，Parikh CR ，Translational Research Investigating Biomarker Endpoints in AKI (TRIBE AKI) Consortium ... -  《-》

Urine Biomarkers and Perioperative Acute Kidney Injury: The Impact of Preoperative Estimated GFR.

The interaction between baseline kidney function and the performance of biomarkers of acute kidney injury (AKI) on the development of AKI is unclear. Post hoc analysis of prospective cohort study. The 1,219 TRIBE-AKI Consortium adult cardiac surgery cohort participants. Unadjusted postoperative urinary biomarkers of AKI measured within 6 hours of surgery. AKI was defined as AKI Network stage 1 (any AKI) or higher, as well as a doubling of serum creatinine level from the preoperative value or the need for post-operative dialysis (severe AKI). Stratified analyses by preoperative estimated glomerular filtration rate (eGFR) ≤ 60 versus > 60mL/min/1.73m(2). 180 (42%) patients with preoperative eGFRs≤60mL/min/1.73m(2) developed clinical AKI compared with 246 (31%) of those with eGFRs>60mL/min/1.73m(2) (P<0.001). For log2-transformed biomarker concentrations, there was a significant interaction between any AKI and baseline eGFR for interleukin 18 (P=0.007) and borderline significance for liver-type fatty acid binding protein (P=0.06). For all biomarkers, the adjusted relative risk (RR) point estimates for the risk for any AKI were higher in those with elevated baseline eGFRs compared with those with eGFRs≤60mL/min/1.73m(2). However, the difference in magnitude of these risks was low (adjusted RRs were 1.04 [95% CI, 0.99-1.09] and 1.11 [95% CI, 1.07-1.15] for those with preoperative eGFRs≤60mL/min/1.73m(2) and those with higher eGFRs, respectively). Although no biomarker displayed an interaction for baseline eGFR and severe AKI, log2-transformed interleukin 18 and kidney injury molecule 1 had significant adjusted RRs for severe AKI in those with and without baseline eGFRs≤60mL/min/1.73m(2). Limited numbers of patients with severe AKI and post-operative dialysis. The association between early postoperative AKI urinary biomarkers and AKI is modified by preoperative eGFR. The degree of this modification and its impact on the biomarker-AKI association is small across biomarkers. Our findings suggest that distinct biomarker cutoffs for those with and without a preoperative eGFR≤60mL/min/1.73m(2) is not necessary.

Koyner JL ，Coca SG ，Thiessen-Philbrook H ，Patel UD ，Shlipak MG ，Garg AX ，Parikh CR ，Translational Research Investigating Biomarker Endpoints for Acute Kidney Injury (TRIBE-AKI) Consortium ，Translational Research Investigating Biomarker Endpoints for Acute Kidney Injury TRIBE-AKI Consortium ... -  《-》