Assessing the predictive value of elevated postoperative syndecan-1 levels for progressive acute kidney injury and kidney replacement therapy necessity in adult cardiac surgery patients.

BACKGROUND: The development of acute kidney injury (AKI) post-cardiac surgery significantly increases patient morbidity and healthcare costs. Prior researches have established Syndecan-1 (SDC-1) as a potential biomarker for endothelial injury and subsequent acute kidney injury development. This study assessed whether postoperative SDC-1 levels could further predict AKI requiring kidney replacement therapy (AKI-KRT) and AKI progression. METHODS: In this prospective study, 122 adult cardiac surgery patients, who underwent valve or coronary artery bypass grafting (CABG) or a combination thereof and developed AKI within 48 h post-operation from May to September 2021, were monitored for the progression to stage 2-3 AKI or the need for KRT. We analyzed the predictive value of postoperative serum SDC-1 levels in relation to multiple endpoints. RESULTS: In the study population, 110 patients (90.2%) underwent cardiopulmonary bypass, of which thirty received CABG or combined surgery. Fifteen patients (12.3%) required KRT, and thirty-eight (31.1%) developed progressive AKI, underscoring the severe AKI incidence. Multivariate logistic regression indicated that elevated SDC-1 levels were independent risk factors for progressive AKI (OR = 1.006) and AKI-KRT (OR = 1.011). The AUROC for SDC-1 levels in predicting AKI-KRT and AKI progression was 0.892 and 0.73, respectively, outperforming the inflammatory cytokines. Linear regression revealed a positive correlation between SDC-1 levels and both hospital (ß = 0.014, p = 0.022) and ICU stays (ß = 0.013, p < 0.001). CONCLUSION: Elevated postoperative SDC-1 levels significantly predict AKI progression and AKI-KRT in patients following cardiac surgery. The study's findings support incorporating SDC-1 level monitoring into post-surgical care to improve early detection and intervention for severe AKI.

Predictive value of perioperative NT-proBNP levels for acute kidney injury in patients with compromised renal function undergoing cardiac surgery: a case control study.

BACKGROUND: Acute kidney injury (AKI) significantly increases morbidity and mortality following cardiac surgery, especially in patients with pre-existing renal impairments. N-terminal pro-B-type natriuretic peptide (NT-proBNP) is a marker of cardiac stress and dysfunction, conditions often exacerbated during cardiac surgery and prevalent in chronic kidney disease (CKD) patients. Elevated NT-proBNP levels can indicate underlying cardiac strain, hemodynamic instability and volume overload. This study evaluated the association between perioperative changes in NT-proBNP levels and the incidence of AKI in this particular patient group. METHODS: This retrospective study involved patients with impaired renal function (eGFR 15-60 ml/min/1.73 m²) who underwent cardiac surgery from July to December 2022. It analyzed the association between the ratio of preoperative and ICU admittance post-surgery NT-proBNP levels and the development of AKI and AKI stage 2-3, based on KDIGO criteria, using multivariate logistic regression models. Restricted cubic spline analysis assessed non-linear associations between NT-proBNP and endpoints. Subgroup analysis was performed to assess the heterogeneity of the association between NT-proBNP and endpoints in subgroups. RESULTS: Among the 199 participants, 116 developed postoperative AKI and 16 required renal replacement therapy. Patients with AKI showed significantly higher postoperative NT-proBNP levels compared to those without AKI. Decreased baseline eGFR and increased post/preoperative NT-proBNP ratios were associated with higher AKI risk. Specifically, the highest quantile post/preoperative NT-proBNP ratio indicated an approximately seven-fold increase in AKI risk and a ninefold increase in AKI stage 2-3 risk compared to the lowest quantile. The area under the receiver operating characteristic curve for predicting AKI and AKI stage 2-3 using NT-proBNP were 0.63 and 0.71, respectively, demonstrating moderate accuracy. Subgroup analysis demonstrated that the positive association between endpoints and logarithmic transformed post/preoperative NT-proBNP levels was consistently robust in subgroup analyses stratified by age, sex, surgery, CPB application, hypertension, diabetes status and fluid balance. CONCLUSION: Perioperative NT-proBNP level changes are predictive of postoperative AKI in patients with pre-existing renal deficiencies undergoing cardiac surgery, aiding in risk assessment and patient management.

Early goal-directed renal replacement therapy in severe pneumonia associated acute kidney injury.

INTRODUCTION: Severe pneumonia is a crucial issue in the development of acute kidney injury (AKI). This study evaluated the efficacy of early goal-directed renal replacement therapy (GDRRT) for the treatment of severe pneumonia-associated AKI. METHODS: In this real-world retrospective cohort study, we recruited 180 patients with severe pneumonia who were hospitalized and received GDRRT in a third-class general hospital in East China between January 1, 2017, and December 31, 2021. Clinical data on baseline characteristics, biochemical indicators, and renal replacement therapy were collected. Patients were divided into Early and Late RRT groups according to fluid status, inflammation progression, and pulmonary radiology. We investigated in-hospital all-cause mortality (primary endpoint) and renal recovery (secondary endpoint) between the two groups. RESULTS: Among the 154 recruited patients, 80 and 74 were in the early and late RRT groups, respectively. There were no significant differences in the demographic characteristics between the two groups. The duration of admission to RRT initiation was significantly shorter in Early RRT group [2.5(1.0, 8.7) d vs. 5.0(1.5,13.5) d, p = 0.027]. At RRT initiation, the patients in the Early RRT group displayed a lower percentage of fluid overload, lower doses of vasoactive agents, higher CRP levels, and higher rates of radiographic progression than those in the Late RRT group. The all-cause in-hospital mortality was significantly lower in the Early RRT group than in Late group (52.5% vs. 86.5%, p < 0.001). Patients in the Early RRT group displayed a significantly higher proportion of complete renal recovery at discharge (40.0% vs. 8.1%, p < 0.001). CONCLUSION: This study clarified that early GDRRT for the treatment of severe pneumonia-associated AKI based on fluid status and inflammation progression, was associated with reduced hospital mortality and better recovery of renal function. Our preliminary study suggests that early initiation of RRT may be an effective approach for severe pneumonia-associated AKI.

Proteinuria is a risk factor for acute kidney injury after cardiac surgery in patients with stages 3-4 chronic kidney disease: a case control study.

BACKGROUND: Acute kidney injury (AKI) is a common complication after cardiac surgery, and preoperative renal dysfunction is an important risk factor. Proteinuria indicates renal structural damage, but there are few studies on proteinuria and the risk of AKI after cardiac surgery in patients with renal dysfunction. This study aimed to elucidate whether proteinuria can predict AKI after cardiac surgery in patients with renal dysfunction. METHODS: Patients with stages 3-4 chronic kidney disease (CKD) who underwent cardiac surgery were included in this retrospective study. AKI was defined according to the KDIGO criteria. The association between proteinuria and AKI in patients with CKD stages 3-4 was investigated. RESULTS: The incidence of AKI in the entire cohort (n = 1546) was 53.55%. The in-hospital mortality of patients with was higher than patients without AKI (AKI vs. no AKI, 4.7 vs. 0.8%, P < 0.001). Multivariate logistic regression analysis showed that proteinuria was an independent risk factor for AKI (trace to 1+ OR 2.37; 2+ -3+ OR 5.16) and AKI requiring renal replacement therapy (AKI-RRT) (trace to 1+ OR 3.64; 2+-3+ OR 5.71). Mild proteinuria (trace to 1+ OR 2.59) was also an independent risk factor for in-hospital death. In patients with diabetes mellitus, mild proteinuria (OR 1.925), instead of severe proteinuria (2-3+), was a risk factor of AKI in patients with kidney dysfunction and diabetes. CONCLUSIONS: In the population of patients with renal dysfunction, the incidence of AKI was high, which significantly compromised renal and overall prognosis. As a simple and inexpensive routine test, preoperative proteinuria still has value in predicting AKI in patients with impaired renal function.

Risk Factors and Prognosis of Acute Kidney Injury after Cardiac Surgery in Patients with Chronic Kidney Disease.

INTRODUCTION: Cardiac surgery-associated acute kidney injury (CSA-AKI) is one of the most prevalent complications of cardiac surgery, while the renal and overall prognoses of chronic kidney disease (CKD) patients with CSA-AKI are extremely poor. However, there is little published information on the occurrence of CSA-AKI in patients with CKD. The purpose of this study was to investigate the risk factors and prognostic factors of cardiac surgery-related AKI in patients with CKD. METHODS: A retrospective study was performed on CKD patients who underwent cardiac surgery at a tertiary referral teaching hospital. CSA-AKI was defined based on the KDIGO criteria. The risk factors for CSA-AKI and the factors affecting renal function recovery at discharge or death in patients with AKI were investigated. RESULTS: Among 1638 CKD patients enrolled, the incidence of CSA-AKI was 50.55%. AKI patients' in-hospital mortality was higher than patients without AKI (AKI vs. no AKI, 4.7 vs. 0.9%, p < 0.001). Multivariate logistic regression analysis showed that male (odds ratio [OR] 1.479), preoperative hypertension (OR 1.548), preoperative hemoglobin <110 g/L (OR 2.389), and aortic clamping time >58 min (OR 1.567) were independent risk factors for AKI after cardiac surgery in patients with CKD. Factors affecting renal function recovery of AKI patients included preoperative diabetes mellitus (OR 0.306), hyperchloremia (OR 0.927), estimate of the glomerular filtration rate (OR 1.034), and AKI progression. Compared with patients with AKI stage 1, the rate of renal function recovery in patients with AKI stage 2 and stage 3 was reduced by 78.9% and 82.3%, respectively. CONCLUSIONS: In the population of patients with CKD, the incidence of CSA-AKI was high, which significantly affected renal and overall prognosis. The prompt intervention of modifiable factors may help improve the prognosis of patients with CKD.

Effect of angiography timing on acute kidney injury after cardiac surgery in patients with preoperative renal dysfunction.

BACKGROUND: Cardiac surgery-associated acute kidney injury (AKI) is one of the common complications of cardiac surgery. Preoperative angiography helps assess heart disease but may increase the risk of AKI. Although more and more patients with preoperative renal dysfunction can undergo cardiac surgery with the advances in surgical techniques, there is little research on the effect of angiography on postoperative AKI in these patients. This study investigates whether angiography increases the risk of AKI after cardiac surgery in patients with preoperative renal dysfunction (15 ≤ eGFR < 60 ml/min/1.73m2). METHODS: Patients with preoperative renal dysfunction (15 ≤ eGFR < 60 ml/min/1.73m2) who underwent angiography and cardiac surgery successively from January 2015 to December 2020 were retrospectively enrolled in this study. The primary outcome was postoperative AKI, defined as the Kidney Disease: Improving Global Outcomes Definition and Staging (KDIGO) criteria. Univariate analysis and multivariate regression were performed to identify the association between angiography timing and AKI. RESULTS: A total of 888 consecutive eligible patients with preoperative renal dysfunction (15 ≤ eGFR < 60 ml/min/1.73m2) were enrolled in this study. The incidence of AKI was 48.31%. Male (OR = 1.903), the interval between angiography and surgery (0-2d OR = 2.161; 3-6d OR = 3.291), cross-clamp duration (OR = 1.009), were identified as predictors for AKI. The interval between angiography and surgery was also associated with AKI in the patients with 15 ≤ eGFR < 30ml/min/1.73m2 (0-2d OR = 4.826; 3-6d OR = 5.252), 30 ≤ eGFR < 45 ml/min/1.73m2 (0-2d OR = 2.952; 3-6d OR = 3.677), but not associated with AKI in patients with 45 ≤ eGFR < 60 ml/min/1.73m2. CONCLUSIONS: In patients with preoperative renal dysfunction, the interval between angiography and cardiac surgery (0-2d and 3-6d) was associated with AKI. For patients with poorer preoperative renal function, the interval between angiography and cardiac surgery is of great concern.

Hemodilution is associated with underestimation of serum creatinine in cardiac surgery patients: a retrospective analysis.

BACKGROUND: Fluid overload is related to the development and prognosis of cardiac surgery-associated acute kidney injury (CSA-AKI). The study is to investigate the influence of serum creatinine (SCr) corrected by fluid balance on the prognosis of patients with cardiac surgery. METHODS: A retrospective study was conducted in 1334 patients who underwent elective cardiac surgery from January 1 to December 31, 2015. Kidney Disease: Improving Global Outcomes (KDIGO) criteria for AKI were applied to identify CSA-AKI. SCr was measured every 24 h during ICU period and was accordingly adjusted for cumulative fluid balance. Changes in SCr, defined as ∆Crea, were determined by difference between before and after adjustment for cumulative fluid balance. All patients were then divided into three groups: underestimation group (∆Crea ≥ P75), normal group (P25 < ∆Crea < P75) and overestimation group (∆Crea ≤ P25). RESULTS: The incidence of AKI increased from 29.5% to 31.8% after adjustment for fluid balance. Patients in underestimation group showed prolonged length of ICU stay compared with normal group and overestimation group (3.2 [1.0-4.0] vs 2.1 [1.0-3.0] d, P < 0.001; 3.2  [1.0-4.0] vs 2.3 [1.0-3.0] d, P < 0.001). Length of hospital stay and mechanical ventilation dependent days in underestimation group were significantly longer than normal group (P < 0.001). Multivariate analysis showed age, baseline SCr and left ventricular ejection fraction were independently associated with underestimation of creatinine. CONCLUSIONS: Cumulative fluid balance after cardiac surgery disturbs accurate measurement of serum creatinine. Patients with underestimation of SCr were associated with poor prognosis.

The Effect of Postoperative Fluid Balance on the Occurrence and Progression of Acute Kidney Injury After Cardiac Surgery.

OBJECTIVES: In addition to the association between positive fluid balance (FB) and acute kidney injury (AKI) after cardiac surgery reported by former studies, this study examined the relationship between FB and progressive AKI. DESIGN: A retrospective, observational study. SETTING: University teaching, grade A tertiary hospital in Shanghai, China. PARTICIPANTS: Adult patients after cardiac surgery from July-December 2016. INTERVENTIONS: Perioperative data relating to postoperative fluid intake and output were collected. AKI progression was defined as a worsening of AKI stage. FB was calculated as (fluid intake [L] - fluid output [L]/body weight [kg] × 100%). MEASUREMENTS AND MAIN RESULTS: The study comprised 1,522 patients. The incidences of AKI and progressive AKI were 33.1% (n = 504) and 18.1% (n = 91), respectively. There was an exponential increase between 24-hour FB and AKI occurrence, and an approximate "U"-shape association between 48-hour FB and AKI progression. Multivariate logistic regression showed that 24-hour FB ≥5% was an independent risk factor for AKI incidence (odds ratio [OR] 3.976; p < 0.001) and 48-hour FB <-5% or ≥3% was associated with an increase of AKI progression (FB <-5%, OR 7.078 [p = 0.031]; FB 3%-5%, OR 6.598 [p = 0.020]; FB ≥5%, OR 16.453 [p < 0.001]). CONCLUSIONS: An exponential increase was found between 24-hour FB and AKI occurrence and a "U"-shape association between 48-hour FB and AKI progression. Both excessively negative and positive accumulative 48-hour FB increased the risk of AKI progression, suggesting cautious monitoring and application of fluid load in clinical practice.

Volume-associated hemodynamic variables for prediction of cardiac surgery-associated acute kidney injury.

BACKGROUND: Delayed diagnosis of acute kidney injury (AKI) is common because the changes in renal function markers often lag injury. We aimed to find optimal non-invasive hemodynamic variables for the prediction of postoperative AKI and AKI renal replacement therapy (RRT). METHODS: The data were collected from 1,180 patients who underwent cardiac surgery in our hospital between March 2015 and Feb 2016. Postoperative central venous pressure (CVP), mean arterial pressure (MAP), heart rate, PaO2, and PaCO2 on ICU admission and daily fluid input and output (calculated as 24 h PFO) were monitored and compared between AKI vs. non-AKI and RRT vs non-RRT cases. RESULTS: The AKI and AKI-RRT incidences were 36.7% (n = 433) and 1.2% (n = 14). Low cardiac output syndromes (LCOSs) occurred significantly more in AKI and RRT than in non-AKI or non-RRT groups (13.2% vs. 3.9%, P < 0.01; 42.9% vs. 7.1%, P < 0.01). CVP on ICU admission was significantly higher in AKI and RRT than in non-AKI and non-RRT groups (11.5 vs. 9.0 mmHg, P < 0.01; 13.3 vs. 9.9 mmHg, P < 0.01). 24 h PFO in AKI and RRT cases were significantly higher than in non-AKI or non-RRT patients (1.6% vs. 0.9%, P < 0.01; 3.9% vs. 0.8%, P < 0.01). The areas under the ROC curves to predict postoperative AKI by CVP on ICU admission (> 11 mmHg) + LCOS + 24 h PFO (> 5%) and to predict AKI-RRT by CVP on ICU admission (> 13 mmHg) + LCOS + 24 h PFO (> 5%) were 0.763 and 0.886, respectively. CONCLUSION: The volume-associated hemodynamic variables, including CVP on ICU admission, LCOS, and 24 h PFO after surgery could predict postoperative AKI and AKI-RRT.

Efficacy of Early Goal-Directed Renal Replacement Therapy for the Treatment of Acute Kidney Injury After Heart Transplantation: A Single-Center 10-Year Experience.

OBJECTIVE: Acute kidney injury (AKI) after heart transplantation is a common and serious complication. The present study aimed to evaluate the efficacy of early goal-directed renal replacement therapy (GDRRT) for the treatment of AKI after heart transplantation. DESIGN: Retrospective, observational study. SETTING: Grade A tertiary hospital that performs more than 4,000 cardiac surgery procedures per year. PARTICIPANTS: Patients who underwent heart transplantation with postoperative AKI and received renal replacement therapy from January 2008 to June 2018. INTERVENTIONS: Patients were divided into a late GDRRT group (LGDRRT) (January 2008-September 2012) or an early GDRRT group (EGDRRT) (October 2012-June 2018). RESULTS: The LGDRRT group comprised 30 patients, and the EGDRRT group comprised 46 patients. Duration between surgery to renal replacement therapy (RRT) initiation in the EGDRRT group was significantly shorter than in the LGDRRT group (1 [1-3] d v 2 [2-3] d; p = 0.020). The in-hospital mortality in the EGDRRT group was significantly lower than that of the LGDRRT group (39.1% v 63.3%; p = 0.039). After multivariate adjustment for confounding factors, the hazard ratio for death in the LGDRRT group relative to the EGDRRT group was 2.028 (95% confidence interval 1.072-3.655; p = 0.048). Length of intensive care unit and hospital stays in the EGDRRT group was significantly shorter than that of the LGDRRT group (26 ± 18 d v 38 ± 20 d; p = 0.008 and 38 ± 33 d v 64 ± 45 d; p = 0.005, respectively). The complete renal recovery rate was much greater in the EGDRRT group than that of the LGDRRT group (50.0% v 20.0%; p < 0.001). Serum creatinine at discharge was significantly less in the EGDRRT group than that of the LGDRRT group (134.8 ± 97.3 µmol/L v 220.7 ± 113.6 µmol/L; p < 0.001). Cost of RRT in the EGDRRT group was significantly less than that of the LGDRRT group (0.54 ± 0.10 v. 0.63 ± 0.11 ten thousand USD; p < 0.001). CONCLUSIONS: For heart transplantation recipients with AKI, EGDRRT can reduce the in-hospital mortality and the length of intensive care unit and hospital stays, improve the complete renal recovery rate, and reduce the cost of RRT.

Postoperative diastolic perfusion pressure is associated with the development of acute kidney injury in patients after cardiac surgery: a retrospective analysis.

BACKGROUND: We aimed to investigate the relationship between the perioperative hemodynamic parameters and the occurrence of cardiac surgery-associated acute kidney injury. METHODS: A retrospective study was performed in patients who underwent cardiac surgery at a tertiary referral teaching hospital. Acute kidney injury was determined according to the KDIGO criteria. We investigated the association between the perioperative hemodynamic parameters and cardiac surgery-associated acute kidney injury to identify the independent hemodynamic predictors for acute kidney injury. Subgroup analysis was further performed in patients with chronic hypertension. RESULTS: Among 300 patients, 29.3% developed acute kidney injury during postoperative intensive care unit period. Multivariate logistic analysis showed the postoperative nadir diastolic perfusion pressure, but not mean arterial pressure, central venous pressure and mean perfusion pressure, was independently linked to the development of acute kidney injury after cardiac surgery (odds ratio 0.945, P = 0.045). Subgroup analyses in hypertensive subjects (n = 91) showed the postoperative nadir diastolic perfusion pressure and peak central venous pressure were both independently related to the development of acute kidney injury (nadir diastolic perfusion pressure, odds ratio 0.886, P = 0.033; peak central venous pressure, odds ratio 1.328, P = 0.010, respectively). CONCLUSIONS: Postoperative nadir diastolic perfusion pressure was independently associated with the development of cardiac surgery-associated acute kidney injury. Furthermore, central venous pressure should be considered as a potential hemodynamic target for hypertensive patients undergoing cardiac surgery.

Early Postoperative Serum Creatinine Adjusted for Fluid Balance Precisely Predicts Subsequent Acute Kidney Injury After Cardiac Surgery.

OBJECTIVES: Cumulative fluid overload may influence acute kidney injury (AKI) diagnosis due to the dilution effect. The authors hypothesized a small increase of early postoperative serum creatinine (SCr) adjusted for fluid balance might have superior discrimination ability in subsequent AKI prediction. DESIGN: Retrospective analyses. SETTING: A single-center study in a university hospital. PARTICIPANTS: The study comprised 1,016 adult patients who underwent elective isolated or combined valve surgery in 2015. INTERVENTIONS: None. MEASUREMENTS AND MAIN RESULTS: Baseline characteristics, intraoperative parameters, and intraoperative and postoperative fluid balance were collected through a retrospective chart review. Early postoperative SCr level was drawn within 12 hours of surgical completion and then measured daily. Early relative changes of SCr were categorized as a cutoff value of 10% with or without adjustment for cumulative fluid balance. Kidney Disease: Improving Global Outcomes criteria were used to detect AKI. Logistic analyses were performed to determine risk factors for subsequent AKI with the inclusion of measured or fluid-adjusted early relative changes of SCr, respectively. In this study, 355 patients (34.9%) developed AKI. Multivariate logistic analyses showed age, weight, European System for Cardiac Operative Risk Evaluation II, and cardiopulmonary bypass duration were associated independently with the development of AKI. Model discrimination for AKI prediction was improved significantly when the addition of measured (area under the receiver operating characteristic curve [AUROC] 0.830) and fluid-adjusted early changes of SCr to the basic model (AUROC 0.850). CONCLUSIONS: Early fluid-adjusted relative changes of SCr could improve the predictive ability for subsequent development of AKI in valve surgery patients.

Impact of cardiac catheterization timing and contrast media dose on acute kidney injury after cardiac surgery.

BACKGROUND: The association between pre-operative cardiac catheterization and cardiac surgery associated acute kidney injury (CSA-AKI) has been reported inconsistently. The purpose of this study is to evaluate the effect of the catheterization timing and contrast media dose on the incidence of postoperative acute kidney injury. METHODS: Patients who underwent cardiac catheterization and cardiac surgery successively from January 2015 to December 2015 were prospectively enrolled in this study. The primary outcome was CSA-AKI which was defined as the Kidney Disease: Improving Global Outcomes Definition and Staging (KDIGO) criteria. Univariate analysis and multivariate regression were performed to identify the predictors for CSA-AKI. Baseline characteristics were balanced with propensity score method for better adjustment. RESULTS: A total of 1069 consecutive eligible patients were enrolled into this study. The incidence of CSA-AKI and AKI requiring renal replacement therapy (AKI-RRT) were 38.5% (412/1069) and 1.9% (20/1069) respectively. Preoperative estimated glomerular filtration rate less than 60 mL/min/1.73m2 (OR = 2.843 95% CI 1.374-5.882), the time interval between catheterization and surgery≤7 days (OR = 2.546, 95% CI 1.548-4.189) and the dose of contrast media (CM) > 240 mg/kg (OR = 2.490, 95%CI 1.392-4.457) were identified as predictors for CSA-AKI. In the patients with the dose of CM > 240 mg/kg, the incidence of CSA-AKI was higher in patients who underwent cardiac catheterization ≤7 days before cardiac surgery than in those of > 7 days before cardiac surgery (39.4% vs. 28.8%, p = 0.025). The longer interval of more than 7 days was revealed to be inversely associated with CSA-AKI through logistic regression (OR = 0.579, 95% CI 0.337-0.994). CONCLUSION: Catheterization within 7 days of cardiac surgery and a dose of CM > 240 mg/kg were associated with the onset of CSA-AKI. For patients who received a dose of CM > 240 mg/kg, postponing the cardiac surgery is potentially beneficial to reduce the risk of CSA-AKI.

Role of elevated red cell distribution width on acute kidney injury patients after cardiac surgery.

BACKGROUND: The aim of the study was to explore associations between elevated red cell distribution width (RDW) and acute kidney injury (AKI) in patients undergoing cardiac surgery (CS-AKI). METHODS: Preoperative, intraoperative and postoperative data of 10,274 patients undergoing cardiac surgery, including demographic data, were prospectively collected from January 2009 to December 2014. Propensity score matching was used on the basis of clinical characteristics and preoperative variables. An elevated RDW was defined as the difference between RDW 24 h after cardiac surgery and the latest RDW before cardiac surgery. RESULTS: A total of 10,274 patients were included in the unmatched cohort, and 3146 patients in the propensity-matched cohort. In the unmatched cohort, the overall CS-AKI incidence was 32.8% (n = 3365) with a hospital mortality of 5.5% (n = 185). In the propensity-matched cohort, the elevated RDW in AKI patients was higher than in patients without AKI (0.3% (0.0%, 0.7%) vs 0.5% (0.1, 1.1%), P <  0.001) and the elevated RDW incidences were 0.4% (0.1%, 0.9%), 0.6% (0.2%, 1.1%) and 1.1% (0.3%, 2.1%) in stage 1, 2 and 3 AKI patients (P <  0.001). Among propensity-matched patients with CS-AKI, the level of elevated RDW in non-survivors was higher than in survivors [1.2% (0.5%, 2.3%) vs 0.5% (0.1%, 1.0%), P <  0.001] and a 0.1% increase in elevated RDW was associated with a 0.24% higher risk of within-hospital mortality in patients with CS-AKI. Estimating the receiver-operating characteristic (ROC) area under the curve (AUC) showed that an elevated RDW had moderate discriminative power for AKI development (AUC = 0.605, 95% CI, 0.586-0.625; P <  0.001) and hospital mortality (AUC = 0.716, 95% CI, 0.640-0.764; P <  0.001) in the propensity-matched cohort. CONCLUSIONS: An elevated RDW might be an independent prognostic factor for the severity and poor prognosis of CS-AKI.

Urinary TIMP-2 and IGFBP7 for the prediction of acute kidney injury following cardiac surgery.

BACKGROUND: Acute kidney injury (AKI) following cardiac surgery is common and associated with poor patient outcomes. Early risk assessment for development of AKI remains a challenge. The combination of urinary tissue inhibitor of metalloproteinase 2 (TIMP-2) and insulin-like growth factor binding protein 7 (IGFBP7) has been shown to be an excellent predictor of AKI following cardiac surgery, but reported studies are for predominately non-Asian populations. METHODS: Adult patients were prospectively enrolled at Zhongshan hospital in Shanghai, China. The primary analysis was prediction of AKI and stage 2-3 AKI by [TIMP-2]*[IGFBP7] measured 4 h after postoperative ICU admission assessed using receiver operating characteristic curve (ROC) analysis. Kinetics of [TIMP-2]*[IGFBP7] following ICU admission were also examined. RESULTS: We prospectively enrolled 57 cardiac surgery patients, of which 20 (35%) developed AKI and 6 (11%) developed stage 2-3 AKI. The area under the ROC curve (AUC) of [TIMP-2]*[IGFBP7] at 4 h after ICU admission was 0.80 (95% confidence interval (CI): 0.68-0.91) for development of AKI and 0.83 (95% CI: 0.69-0.96) for development of stage 2-3 AKI. Urinary [TIMP-2]*[IGFBP7] values at 4 h after ICU admission were significantly (P < 0.001) higher in patients who developed AKI than in patients who did not develop AKI (mean (standard error) of 1.08 (0.34) (ng/mL)2/1000 and 0.29 (0.05) (ng/mL)2/1000, respectively). The time-profile of [TIMP-2]*[IGFBP7] suggests the markers started to elevate by the time of ICU admission in patients who developed AKI and either decreased or remained flat in patients without AKI. CONCLUSION: The combination of urinary TIMP-2 and IGFBP7 4 h after postoperative ICU admission identifies patients at risk for developing AKI, not just stage 2-3 AKI following cardiac surgery.

[A long-term outcome study of acute kidney injury after cardiac surgery].

OBJECTIVE: To evaluate the long-term outcome of acute kidney injury (AKI) during hospitalization after cardiac surgery. METHODS: 1 770 patients underwent cardiac surgery in Fudan University Zhongshan Hospital from April 2009 to February 2011 were enrolled. Based on the Kidney Disease: Improving Global Outcomes (KDIGO) guideline of AKI, the patients were divided into the AKI and the non-AKI groups, and followed up for 2 years. The 2-year survival rate and incidence of the advanced chronic kidney disease (CKD) was compared between the two groups.Factors influencing the 2-year survival rate and incidence of the advanced CKD were also analyzed. RESULTS: Among all the patients, 715 (40.4%) of them were developed AKT. (1) The 2-year survival rate of the AKI group was lower than that of the non-AKI group (83.2% vs 93.6%;P < 0.05). Compared with the non-AKI group, AKI group had an increased risk for death with the hazard ratio of 1.710 (95%CI 1.250-2.340). COX regression analysis showed that AKI was an independent factor for death with the risk intensity just less than diabetes and chronic cardiac insufficiency. The advanced age, the preoperative history of chronic cardiac insufficiency and the time of staying in ICU also significantly increased the risk of death. (2) Compared with patients without AKI (0.2%), the incidence of the 2-year of advanced CKD was higher in patients with AKI (6.7%;P < 0.05) with an hazard ratio of 31.220 (95%CI 7.550-129.110). COX regression analysis showed that AKI was still the independent risk factor for advanced CKD after adjustment of other factors.In addition, diabetes, the time of the cardiopulmonary bypass and the time of staying in ICU were also associated with the risk for the advanced CKD. CONCLUSIONS: AKI is common after cardiac surgery, which was associated with a decrease in the 2-year survival rate and an increase in the incidence of advanced CKD of patients, which emphasized the importance of prevention and treatment of AKI, and close follow-up of renal function for the improvement of patient long-term prognosis.

Syndecan-1 shedding destroys epithelial adherens junctions through STAT3 after renal ischemia/reperfusion injury.

Adherens junctions between tubular epithelial cells are disrupted in renal ischemia/reperfusion (I/R) injury. Syndecan-1 (SDC-1) is involved in maintaining cell morphology. We aimed to study the role of SDC-1 shedding induced by renal I/R in the destruction of intracellular adherens junctions. We found that SDC-1 shedding was increased while the expression of E-cadherin was decreased. This observation was accompanied by the activation of STAT3 in the kidneys. Inhibiting the shedding of SDC-1 induced by I/R could alleviate this effect. Mild renal I/R could induce more severe renal injury, lower E-cadherin expression, damaged cell junctions, and activated STAT3 in knockout mice with the tubule-specific deletion of SDC-1 mice. The results in vitro were consistent with those in vivo. Inhibiting the shedding of SDC-1 could alleviate the decreased expression of E-cadherin and damage of cell adherens junctions through inhibiting the activation of STAT3 during ischemic acute kidney injury.

Suppressing Syndecan-1 Shedding to Protect Against Renal Ischemia/Reperfusion Injury by Maintaining Polarity of Tubular Epithelial Cells.

ABSTRACT: Syndecan-1 (SDC-1), a type of heparan sulfate proteoglycan on the surface of epithelial cells, is involved in maintaining cell morphology. Loss of cell polarity constitutes the early stage of ischemic acute kidney injury (AKI). This study investigated the role of SDC-1 shedding in I/R-induced AKI and the underlying mechanisms. Levels of the shed SDC-1 in the serum were measured with ELISA 12 and 24 h after reperfusion in renal I/R model mice. Na+/K+-ATPase-α1 expression was evaluated using western blotting in vivo and immunofluorescence in hypoxia/reoxygenation (H/R) cysts. Renal tubular epithelial cell apoptosis was measured using TUNEL in vivo and flow cytometry in vitro. Furthermore, plasma syndecan-1 (pSDC-1) levels were measured in patients at the time of anesthesia resuscitation after cardiac surgery. We found that shed SDC-1 levels increased and Na+/K+-ATPase-α1 expression decreased after H/R in the three-dimensional (3D) tubular model, and this state was exacerbated with extended period of hypoxia. After the inhibition of SDC-1 shedding by GM6001, SDC-1 and Na+/K+-ATPase-α1 expression was restored, while H/R-induced apoptosis was decreased. In vivo, SDC-1 shedding was induced by renal I/R and was accompanied with a loss of renal tubular epithelial cell polarity and increased apoptosis. GM6001 pretreatment protected against I/R injury by alleviating the disruption of cell polarity and apoptosis. pSDC-1 levels were significantly higher in AKI patients than in non-AKI patients. ROC curve showed that the accuracy of pSDC-1 for AKI prediction was 0.769. In conclusion, inhibition of I/R-induced SDC-1 shedding could contribute to renal protection by restoring the loss of cell polarity and alleviating apoptosis in tubular epithelial cells.

Effects of hyperuricaemia, with the superposition of being overweight and hyperlipidaemia, on the incidence of acute kidney injury following cardiac surgery: a retrospective cohort study.

OBJECTIVES: Acute kidney injury (AKI) is a common complication of cardiac surgery. This study aimed to explore the effects of hyperuricaemia, being overweight and hyperlipidaemia as risk factors for AKI in patients following cardiac surgery (cardiac surgery-associated acute kidney injury (CSA-AKI)). DESIGN: Retrospective observational study. SETTING: University teaching, grade-A tertiary hospital in Shanghai, China. PARTICIPANTS: Patients who underwent cardiac surgery from July 2015 to December 2015 in Zhongshan Hospital, Fudan University. MAIN OUTCOME MEASURES: We investigated the effect of hyperuricaemia, in combination with being overweight and hyperlipidaemia, on the risk of CSA-AKI. RESULTS: A total of 1420 patients were enrolled. The AKI incidence in the highest uric acid group was 44.4%, while that in the lowest uric acid group was 28.5% (p<0.001). Patients in the higher uric acid quartiles were more likely to be overweight and hyperlipidaemic at the same time (p<0.001). Multivariate logistic regression analysis showed that hyperuricaemia was an independent risk factor for AKI (OR=1.237, 95% CI 1.095 to 1.885; p=0.009); being overweight or hyperlipidaemia alone was not an independent risk factor, but the combination of being overweight and hyperlipidaemia was (OR=1.544, 95% CI 1.059 to 2.252; p=0.024). In the final model, the OR value increased to 3.126 when hyperuricaemia was combined with being overweight and hyperlipidaemia, and the Hosmer-Lemeshow test showed that all three models fit well (p=0.433, 0.638 and 0.597, respectively). CONCLUSIONS: The combination of being overweight and having hyperlipidaemia was an independent risk factor, but being overweight or having hyperlipidaemia alone was not. The combination of hyperuricaemia, being overweight and hyperlipidaemia further increased the risk of CSA-AKI.

Improvement of cardiac function after coronary artery bypass grafting surgery reduces the risk of postoperative acute kidney injury.

BACKGROUND: Pre-existing renal dysfunction is an independent risk factor for cardiac surgery-associated acute kidney injury (AKI). We aimed to investigate whether the improvement of postoperative cardiac function after coronary artery bypass grafting (CABG) surgery would affect the risk of AKI in patients with different levels of baseline renal function. METHODS: Data were collected from patients who underwent CABG surgery from January 2018 to April 2019. Patients were divided into normal (GFR ≥ 90 ml/min/1.73 m2 ), non-CKD (60≤GFR < 90 ml/min/1.73 m2 ), and CKD (GFR < 60 ml/min/1.73 m2 ) groups. Improvement in cardiac function was defined as △LVEF (postoperative LVEF-preoperative LVEF) ≥ 10% preoperative LVEF. Patients were further divided into subgroups according to postoperative cardiac function improvement. RESULTS: A total of 1365 patients were enrolled, including 793 (58.1%) in the normal group, 476 (34.9%) in the non-CKD group, and 96 (7.0%) in the CKD group. The AKI incidence in the normal, non-CKD, and CKD groups was 22.2%, 28.4%, and 40.6%, respectively. Patients with improved cardiac function in the non-CKD and CKD groups had significantly lower AKI incidence than those without improved cardiac function (22.8% vs. 36.9%, p = .002% and 32.8% vs. 54.3%, p = .037, respectively). For non-CKD patients with improved cardiac function, the serum creatinine at discharge was significantly lower than its preoperative serum creatinine (0.8 ± 0.5 vs 1.2 ± 0.9 mg/dl, p = .002). Multivariate logistic regression analysis showed that the improvement in cardiac function could reduce the risk for postoperative AKI in non-CKD patients but not in CKD patients. CONCLUSIONS: For patients with renal dysfunction and mildly reduced eGFR (60≤GFR < 90 ml/min/1.73 m2 ), improved cardiac function after CABG surgery can reduce the serum creatinine level and reduce the risk for postoperative AKI.