Cardiac Surgery-associated Acute Kidney Injury Research Articles

Cardiac Surgery-Associated Acute Kidney Injury.

AKI is a common and serious complication of cardiac surgery that has a significant impact on patient morbidity and mortality. The Kidney Disease Improving Global Outcomes definition of AKI is widely used to classify and identify AKI associated with cardiac surgery (cardiac surgery-associated AKI [CSA-AKI]) on the basis of changes in serum creatinine and/or urine output. There are various preoperative, intraoperative, and postoperative risk factors for the development of CSA-AKI which should be recognized and addressed as early as possible to expedite its diagnosis, reduce its occurrence, and prevent or ameliorate its devastating complications. Crucial issues are the inaccuracy of serum creatinine as a surrogate parameter of kidney function in the perioperative setting of cardiothoracic surgery and the necessity to discover more representative markers of the pathophysiology of AKI. However, except for the tissue inhibitor of metalloproteinase-2 and insulin-like growth factor binding protein 7 ratio, other diagnostic biomarkers with an acceptable sensitivity and specificity are still lacking. This article provides a comprehensive review of various aspects of CSA-AKI, including pathogenesis, risk factors, diagnosis, biomarkers, classification, prevention, and treatment management.

Mechanism and clinical role of TIMP-2 and IGFBP-7 in cardiac surgery-associated acute kidney injury: A review.

Acute kidney injury (AKI) is a common postoperative complication, but there is still a lack of accurate biomarkers. Cardiac surgery-associated AKI is the most common cause of major-surgery-related AKI, and patients requiring renal replacement therapy have high mortality rates. Early diagnosis, intervention, and management are crucial for improving patient prognosis. However, diagnosing AKI based solely on changes in serum creatinine level and urine output is insufficient, as these changes often lag behind actual kidney damage, making early detection challenging. Biomarkers such as tissue inhibitor of metalloproteinases-2 (TIMP-2) and insulin-like growth factor-binding protein-7 (IGFBP-7) have been found to be significant predictors of moderate-to-severe AKI when combined with urine content analysis. This article reviews the mechanism of biomarkers TIMP-2 and IGFBP-7 in AKI and provides a comprehensive overview of the clinical effects of TIMP-2 and IGFBP-7 in cardiac surgery-associated AKI, including prediction, diagnosis, and progression.

#2593 Comparison of four predictive scoring models as assessment tools for cardiac surgery-associated acute kidney injury in post cardiac surgery patients

Abstract Background and Aims Cardiac surgery-associated acute kidney injury (CSA-AKI) is a predominant contributor to hospital-acquired AKI in ICU following sepsis. Despite a rising frequency of CSA-AKI, currently examined predictive models have not consistently delivered accurate stratification. Utilizing risk stratification systems offers clinicians the opportunity to identify patients at high risk, extend monitoring intervals, facilitate timely referral to nephrology services, and promptly initiate effective preventive and therapeutic interventions known to enhance renal function. This study seeks to identify the most effective model by comparing four established predictive scoring systems. The objective of this single-center retrospective, cross sectional study is to compare the clinical values of the Cleveland Clinical Score, Mehta Score, Simplified Renal Index and Acute Kidney Injury following Cardiac Surgery (AKICS) Score in predicting CS-AKI among patients who underwent cardiac surgery. Method A comprehensive examination of medical records was conducted for all individuals who underwent open-heart surgery between January 2010 and January 2019. Those patients who had CSA-AKI were subsequently identified. These identified individuals underwent assessment using the four predictive scoring models, leading to their categorization into high or low-risk groups for AKI development. Binary logistics regression was then used to describe the association between CSA-AKI development and the four scoring methods as predictors. Results Among the 114 cases of open-heart surgeries, 86 were eligible for inclusion in the study. Half of the patients, specifically 43 individuals (50%), developed CS-AKI, with 5 requiring renal replacement therapy. Among the four scoring methods evaluated, only the Mehta score (95% CI, p 0.019) and AKICS score (95% CI, p 0.011) demonstrated statistical significance in predicting CS-AKI. The odds ratios for both the Mehta Score (1.10) and AKICS Score (1.19) exceeded 1, suggesting that an increase in either score is associated with a higher likelihood of AKI occurrence. Conversely, the Cleveland Clinical Score (p 0.106) and Simplified Renal Index (p 0.399) were not found to be predictive. Conclusion In this single-center study, both the Mehta score and the AKICS scoring system demonstrated predictability for AKI after open-heart surgery. However, the Cleveland Clinical Scoring and Simplified Renal Index did not exhibit predictive capability in this context.

#624 The impact of hemoadsorption in patients with borderline chronic kidney disease undergoing coronary artery bypass grafting

Abstract Background and Aims With an annual incidence of up to 30%, cardiac surgery–associated acute kidney injury (CSA-AKI) may be one of the most underappreciated yet frequent complications and renal protective adjustments are crucial. We evaluated the impact of hemoadsorption as adjunctive therapy on clinical outcome in Kidney Disease Improving Global Outcomes (KDIGO) G2/A2) patients undergoing coronary artery bypass grafting (CABG). Method During a three-year period, 40 patients undergoing CABG with borderline chronic kidney disease (KDIGO-G2/A2) were treated with adjunctive hemoadsorption therapy and were compared by propensity score-matched 40 patients (KDIGO G2/A2) (Control). Primary endpoints were the need for renal replacement therapy (RRT)/dialysis and/or worsening of KDIGO stage in the perioperative period. Secondary endpoints were the change in inflammatory biomarkers, vasopressor requirement and ICU/hospital stay. In the study group, a 300 mL hemoadsorber (Cytosorbents Inc, NJ) was used for the entire duration of cardiopulmonary bypass (CPB). All patients were prepared via enhanced recovery after surgery (ERAS) protocol and surgical procedures were performed under moderate hypothermia with pulsatile flow and ultrafiltration. Patients with septic shock, limited life expectancy and refused to give consent were excluded. Results After institutional ethics committee approval was obtained, written informed consent was received from each patient. No significant difference was noted between groups in demographic, operative data and preoperative baseline laboratory. At the end of CPB; s-Creatinine (mg/dL) (1.85 ± 0.6 vs 2.751 ± 0.6; p = 0.035), NT-proBNP (pg/L) (130 ± 30 vs 180 ± 40; p = 0.04), IL-6 (pg/mL) (8.2 ± 4 vs 22.2 ± 4; p = 0.012) and myoglobulin (pg/L) (210 ± 75 vs 310 ± 80; p = 0.04) levels were significantly lower in the study group versus control. Clinical outcome is summarized in Figure. Conclusion This pioneering study demonstrated the additional protective effects of hemoadsorption in patients with borderline chronic kidney disease (KDIGO-G2/A2) undergoing CABG. Elimination of inflammatory parameters might be a complementary mechanism resulting in lesser worsening of kidney function/need of RRT and ICU stay. These findings require validation in large, multicenter trials.

#976 Empagliflozin limits AKI incidence and severity following cardiac surgery: an open-label phase IV randomized pilot study

Abstract Background and Aims Cardiac surgery-associated acute kidney injury (CSA-AKI) is a frequent complication of cardiac surgery assisted by cardiopulmonary bypass (CPB). Currently, no effective preventative strategies exist to reduce the incidence of acute kidney injury (AKI). Sodium-glucose transport protein 2 (SGLT2) inhibitors are effective in reducing the incidence of AKI in studies conducted in patients with chronic kidney disease. Therefore, we hypothesized that perioperative SGLT2 inhibition could reduce the incidence of CSA-AKI. Method In this open-label phase IV, randomized, parallel-group, balanced (1:1), pilot study, adult patients undergoing elective cardiac surgery with CPB were randomized to receive 10 mg empagliflozin per os once daily three days before surgery until two days after surgery, or standard care. The primary outcome was AKI incidence according to the Kidney Disease: Improving Global Outcomes (KDIGO) criteria. Other outcomes included hypoxia-inducible factor 1 alpha (HIF1A) and urinary Kidney Injury Molecule (KIM-1), urinary neutrophil gelatinase associated lipocalin (NGAL) and metabolic parameters such as plasma ketone and glucose concentrations. Results Between March 2022 and April 2023, 60 patients were randomized to empagliflozin (n = 29) or control (n = 31). All patients who underwent cardiac surgery with CPB were included in the intention-to-treat analysis (n = 25; empagliflozin group, n = 30; control group). SGLT2 inhibition significantly reduced the incidence of all stages of AKI (20% vs 66.7%; absolute difference 46%, 95% CI .13 to .63, P < .001). This decline in AKI incidence was reflected in the kidney biomarkers. SGLT2 inhibition also significantly reduced the number of patients with postoperative hyperglycemia (28% vs 60%; absolute difference 32%, 95% CI −56.8 to −7.2, P = .029). We observed no differences in the incidence of neither ketoacidosis nor hypoglycemic events. Conclusion Perioperative SGLT2 inhibition, compared with standard of care, demonstrated a significant reduction in AKI incidence rates. These findings merit validation in a larger placebo-controlled trial which is currently ongoing. Supplementary figures:

Sex bias in prediction and diagnosis of cardiac surgery associated acute kidney injury

BackgroundFemale sex has been recognized as a risk factor for cardiac surgery associated acute kidney injury (CS-AKI). The current study sought to evaluate whether female sex is a risk factor for CS-AKI, or modifies the association of peri-operative change in serum creatinine with CS-AKI.MethodsObservational study of adult patients undergoing cardiac surgery between 2000 and 2019 in a single U.S. center. The main variable of interest was registered patient sex, identified from electronic medical records. The main outcome was CS-AKI within 2 weeks of surgery.ResultsOf 58526 patients, 19353 (33%) were female; 12934 (22%) incurred AKI based on ≥ 0.3 mg/dL or ≥ 50% rise in serum creatinine (any AKI), 3320 (5.7%) had moderate to severe AKI, and 1018 (1.7%) required dialysis within 2 weeks of surgery. Female sex was associated with higher risk for AKI in models that were based on preoperative serum creatinine (OR, 1.35; 95% CI, 1.29–1.42), and lower risk with the use of estimated glomerular filtration, (OR, 0.90; 95% CI, 0.86–0.95). The risk for moderate to severe CS-AKI for a given immediate peri-operative change in serum creatinine was higher in female compared to male patients (p < .0001 and p < .0001 for non-linearity), and the association was modified by pre-operative kidney function (p < .0001 for interaction).ConclusionsThe association of patient sex with CS-AKI and its direction was dependent on the operational definition of pre-operative kidney function, and differential outcome misclassification due to AKI defined by absolute change in serum creatinine.

Cardiac Surgery-Associated Acute Kidney Injury in Children after Cardiopulmonary Bypass

Cardiac surgery-associated acute kidney injury (CSA-AKI) is a complication of cardiopulmonary bypass surgery that frequently occurs in children. The increased availability of pediatric cardiac surgery leads to yearly increases in congenital heart disease (CHD) procedures performed worldwide. The number of complications, including pediatric CSA-AKI, has also increased. Children with CSA-AKI have worse postoperative periods and require more complex post-op intensive care. Thus, the timely commencement of interventions to prevent and to treat kidney injury in CHD children are one of a leading goals of pediatric cardiac intensive care.

The Preventive Role of Glutamine Supplementation in Cardiac Surgery-Associated Kidney Injury from Experimental Research to Clinical Practice: A Narrative Review.

Acute kidney injury represents a significant threat in cardiac surgery regarding complications and costs. Novel preventive approaches are needed, as the therapeutic modalities are still limited. As experimental studies have demonstrated, glutamine, a conditionally essential amino acid, might have a protective role in this setting. Moreover, the levels of glutamine after the cardiopulmonary bypass are significantly lower. In clinical practice, various trials have investigated the effects of glutamine supplementation on cardiac surgery with encouraging results. However, these studies are heterogeneous regarding the selection criteria, timing, dose, outcomes studied, and way of glutamine administration. This narrative review aims to present the potential role of glutamine in cardiac surgery-associated acute kidney injury prevention, starting from the experimental studies and guidelines to the clinical practice and future directions.

Evaluating the Prevalence of Cardiac Surgery–associated Acute Kidney Injury After Septal Myectomy Combined With Concomitant Procedures in Obstructive Hypertrophic Cardiomyopathy

ObjectivesHypertrophic obstructive cardiomyopathy (HOCM) may be treated by septal myectomy. Cardiac surgery-associated acute kidney injury (CSA-AKI) is a common complication, but little is known about its incidence after septal myectomy. The objectives were to (i) evaluate the prevalence of CSA-AKI after septal myectomy and (ii) identify potential perioperative and phenotype-related factors contributing to CSA-AKI. DesignRetrospective database analysis with new data analysis. SettingSingle expertise university academic centre for septal myectomy HOCM patients. ParticipantData from 238 HOCM patients operated with septal myectomy between 2005-2022. InterventionsCSA-AKI was stratified by the Kidney Disease: Improving Global Outcomes (KDIGO) guidelines by measurement of creatinine and urine production. Important HOCM phenotype-related and perioperative factors were analysed for their possible association with CSA-AKI. Measurements and Main ResultsCSA-AKI occurred in 45% of patients, of these, 55% were classified as KDIGO stage I, and the remaining 45% as stage II, with no chronic kidney damage being observed. Moreover, there were no phenotypical or perioperative characteristics that were more prevalent in the CSA-AKI cohort. However, the use of beta-blockers and coronary artery disease were more prevalent in the CSA-AKI cohort. ConclusionsCSA-AKI is a common complication after septal myectomy, but was transient and kidney function recovered in all patients.

La dexmedetomidina mitiga la insuficiencia renal aguda tras la cirugía de revascularización coronaria: un ensayo clínico prospectivo

Introduction and objectivesTo evaluate the impact of dexmedetomidine impact on cardiac surgery-associated acute kidney injury (CSA-AKI), kidney function, and metabolic and oxidative stress in patients undergoing coronary artery bypass grafting with heart-lung machine support. MethodsA randomized double-masked trial with 238 participants (50-75 years) undergoing coronary artery bypass grafting was conducted from January 2021 to December 2022. The participants were divided into Dex (n=119) and NS (n = 119) groups. Dex was administered at 0.5 mcg/kg over 10minutes, then 0.4 mcg/kg/h until the end of surgery; the NS group received equivalent saline. Blood and urine were sampled at various time points pre- and postsurgery. The primary outcome measure was the incidence of CSA-AKI, defined as the occurrence of AKI within 96hours after surgery. ResultsThe incidence of CSA-AKI was significantly lower in the Dex group than in the NS group (18.26% vs 32.46%; P=.014). Substantial increases were found in estimated glomerular filtration rate value at T4–T6 (P<.05) and urine volume 24hours after surgery (P<.01). Marked decreases were found in serum creatinine level, blood glucose level at T1–T2 (P<.01), blood urea nitrogen level at T3–T6 (P<.01), free fatty acid level at T2–T3 (P<.01), and lactate level at T3–T4 (P<.01). ConclusionsDex reduces CSA-AKI, potentially by regulating metabolic disorders and reducing oxidative stress.Registered with the Chinese Clinical Study Registry (No. ChiCTR2100051804).

Cystatin c as an early marker of cardiac surgery associated-acute kidney injury in children in Nigeria

Cystatin c as an early marker of cardiac surgery associated-acute kidney injury in children in Nigeria

Acute Dapagliflozin Administration Ameliorates Cardiac Surgery-Associated Acute Kidney Injury in a Rabbit Model.

Several studies have shown that sodium-glucose cotransporter-2 inhibitors have a renoprotective effect on acute kidney injury (AKI), but their effect on cardiac surgery-associated AKI is unknown.Methods and Results: AKI was induced in 25 rabbits without diabetes mellitus by cardiopulmonary bypass (CPB) for 2 h and they were divided into 5 groups: sham; dapagliflozin-treated sham; CPB; dapagliflozin-treated CPB; and furosemide-treated CPB (n=5 in each group). Dapagliflozin was administered via the femoral vein before initiating CPB. Kidney tissue and urine and blood samples were collected after the surgical procedure. There were no differences in the hemodynamic variables of each group. Dapagliflozin reduced serum creatinine and blood urea nitrogen concentrations, and increased overall urine output (all P<0.05). Hematoxylin and eosin staining showed that the tubular injury score was improved after dapagliflozin administration (P<0.01). Dapagliflozin administration mitigated reactive oxygen species and kidney injury molecule-1 as assessed by immunohistochemistry (both P<0.0001). Protein expression analysis showed improvement of inflammatory cytokines and apoptosis, and antioxidant enzyme expression was elevated (all P<0.05) through activation of the nuclear factor erythroid 2-related factor 2 pathway (P<0.01) by dapagliflozin. Acute intravenous administration of dapagliflozin protects against CPB-induced AKI. Dapagliflozin may have direct renoprotective effects in renal tubular cells.

Perfusion quality odds (PEQUOD) trial: validation of the multifactorial dynamic perfusion index as a predictor of cardiac surgery-associated acute kidney injury.

The multifactorial dynamic perfusion index was recently introduced as a predictor of cardiac surgery-associated acute kidney injury. The multifactorial dynamic perfusion index was developed based on retrospective data retrieved from the patient files. The present study aims to prospectively validate this index in an external series of patients, through an on-line measure of its various components. Inclusion criteria were adult patients undergoing cardiac surgery with cardiopulmonary bypass. Data collection included preoperative factors and cardiopulmonary bypass-related factors. These were collected on-line using a dedicated monitor. Factors composing the multifactorial dynamic perfusion index are the nadir haematocrit, the nadir oxygen delivery, the time of exposure to a low oxygen delivery, the nadir mean arterial pressure, cardiopulmonary bypass duration, the use of red blood cell transfusions and the peak arterial lactates. Two hundred adult patients were investigated. The multifactorial dynamic perfusion index had a good (c-statistics 0.81) discrimination for cardiac surgery-associated acute kidney injury (any stage) and an excellent (c-statistics 0.93) discrimination for severe patterns (stage 2-3). Calibration was modest for cardiac surgery-associated acute kidney injury (any stage) and good for stage 2-3. The use of vasoconstrictors was an additional factor associated with cardiac surgery-associated acute kidney injury. The multifactorial dynamic perfusion index is validated for discrimination of cardiac surgery-associated acute kidney injury risk. It incorporates modifiable risk factors, and may help in reducing the occurrence of cardiac surgery-associated acute kidney injury.

Tissue Inhibitor Metalloproteinase-2·IGF-Binding Protein 7 for the Prediction of Acute Kidney Injury following Cardiac Surgery

Introduction: Cardiac surgery-associated acute kidney injury (CSA-AKI) is a common complication associated with increased morbidity and mortality. Tissue inhibitor metalloproteinase-2·insulin-like growth factor-binding protein 7 (TIMP-2·IGFBP7) determines tubular stress markers, which may occur prior to tubular damage. Previous studies on the use of TIMP-2·IGFBP7 for the prediction of CSA-AKI showed divergent results. Therefore, this study aimed to explore the predictive value of TIMP-2·IGFBP7 measurements for the early detection of acute kidney injury (AKI) and short-term adverse outcomes after cardiac surgery. Methods: In the prospective cohort study, blood and urine samples were collected 6–12 h after cardiac surgery. Blood samples to monitor serum creatinine levels were additionally extracted from days 1 to 7. AKI was defined based on the KDIGO consensus guidelines. AKI within 7 days following surgery was the primary outcome. The initiation of renal replacement therapy, in intensive care unit mortality, and the combination of both were secondary outcomes. Results: A total of 557 patients were enrolled; 134 (24.06%) of them developed AKI and 33 (5.9%) had moderate or severe AKI. AKI developed more frequently in elderly patients with diabetes or with higher baseline serum creatinine levels. Patients with AKI had higher EuroSCORE II, Cleveland Clinic Score, and simplified renal index (SRI) than those without AKI. Urinary TIMP-2·IGFBP7 was significantly higher in patients with AKI. The area under the curve was 0.66 in predicting all AKI and 0.70 in predicting stages 2 and 3 AKI. The resulting sensitivity and specificity were 44.0% and 83.9%, respectively, for a calculated threshold TIMP-2·IGFBP7 value of 0.265 (ng/mL)2/1,000. The TIMP-2·IGFBP7 values, SRI score, and age were significantly associated with AKI within 7 days postoperatively. A total of 33 patients reached the composite endpoint; the percentage of patients who reached the composite endpoint in the TIMP-2·IGFBP7 of >0.265 (ng/ml)2/1,000 group was significantly higher than that of ≤0.265 (ng/mL)2/1,000 group. Conclusions: Postoperative implementation of TIMP-2·IGFBP7 improved the prediction of CSA-AKI and may aid in identifying patients at risk of short-term adverse outcomes. We identified an ideal calculated cutoff value of 0.265 (ng/mL)2/1,000 for the prediction of CSA-AKI among all AKI patients.

Perioperative Left Ventricular Assist Device Use in Patients With Reduced Ejection Fraction Reduces Cardiac Surgery-Associated Acute Kidney Injury.

Background Cardiac surgery may precipitate acute kidney injury (AKI), particularly in patients with poor baseline cardiac function. This is thought to be due to intraoperative renal hypoperfusion, which results in increased morbidity and mortality. This study evaluated the perioperative use of the Impella LD (Abiomed, Danvers, MA) left ventricular assist device (LVAD) in the prevention of postoperative AKI in patients with reduced left ventricular ejection fraction (LVEF) undergoing cardiac surgery. Methods A retrospective analysis was performed at Northwest Medical Center, Tucson, AZ, USA, on patients undergoing valve surgery, coronary arterybypassgrafting(CABG), or both by a single surgeon. Those with preoperative LVEF ≤35% and preoperative serum creatinine ≥1 mg/dL were included and segregated based on intraoperative LVAD implantation. Postoperative renal functionwas assessed using serum creatinine levels and KDIGO (Kidney Disease Improving Global Outcomes) criteria to define AKI. Results Twenty-three patients were enrolled. There were no significant differences in age, demographics, baseline characteristics, or comorbidities between the treatment (n = 12) and the control group (n = 11). In the treatment group, 8% developed AKI by POD#7, while 64% of controls did. The treatment group had a significantly lower mean creatinine change from POD#0-7 (0.07 vs. 0.59, p = 0.02). However, there was no significant difference between groups in the mean creatinine change from baseline to discharge (0.46 vs. 0.42, p = 0.47). Conclusions Our study suggests that intraoperative Impella implantation may reduce the incidence of early postoperative AKI. LVAD implantation is an approach to increase and ensure adequate end-organ (renal) perfusion andcan improve postoperative recovery without dialysis requirements. Additional studies are required to understand its protective effects during the perioperative period fully.

Amino acids to prevent cardiac surgery-associated acute kidney injury: a randomized controlled trial

BackgroundThis study aimed to examine the preventive effect of amino acids on postoperative acute kidney injury (AKI).MethodsThis was single-center, patient- and assessor-blinded, randomized controlled trial. Patients who underwent aortic surgery with cardiopulmonary bypass were included. The intervention group received 60 g/day of amino acids for up to 3 days. The control group received standard care. The primary outcome was the incidence of AKI. We assessed the effect of amino acids on AKI using a Cox proportional hazards regression model.ResultsSixty-six patients were randomly assigned to the control or intervention group. One patient in the control group withdrew consent after randomization. The incidence of AKI was 10 patients (30.3%) in the intervention group versus 18 patients (56.2%) in the control group (adjusted hazard ratio, 0.44; 95% confidence interval, 0.20–0.95; P = 0.04).ConclusionsThis trial demonstrated a significant reduction in AKI incidence with amino acid supplementation.Trial registrationjRCT, jRCTs051210154. Registered 31 December 2021, https://jrct.niph.go.jp/re/reports/detail/69916

Hemodynamic Determinants of Cardiac Surgery-Associated Acute Kidney Injury.

Examine the: 1) relative role of hemodynamic determinants of acute kidney injury (AKI) obtained in the immediate postcardiac surgery setting compared with established risk factors, 2) their predictive value, and 3) extent mediation via central venous pressure (CVP) and mean arterial pressure (MAP). Retrospective observational study. The main outcome of the study was moderate to severe AKI, per kidney disease: improving global outcomes, within 14 days of surgery. U.S. academic medical center. Adult patients undergoing cardiac surgery between January 2000 and December 2019 (n = 40,426) in a single U.S.-based medical center. Pulmonary artery catheter measurements were performed at a median of 102 minutes (11, 132) following cardiopulmonary bypass discontinuation. None. The median age of the cohort was 67 years (58, 75), and 33% were female; 70% had chronic hypertension, 29% had congestive heart failure, and 3% had chronic kidney disease. In a multivariable model, which included comorbidities and traditional intraoperative risk factors, CVP (p < 0.0001), heart rate (p < 0.0001), cardiac index (p < 0.0001), and MAP (p < 0.0001), were strong predictors of AKI, and superseded factors such as surgery type and cardiopulmonary bypass duration. The cardiac index had a significant interaction with heart rate (p = 0.026); a faster heart rate had a differentiating effect on the relationship of cardiac index with AKI, where a higher heart rate heightened the risk of AKI primarily in patients with low cardiac output. There was also significant interaction observed between CVP and MAP (p = 0.009); where the combination of elevated CVP and low MAP had a synergistic effect on AKI incidence. Hemodynamic factors measured within a few hours of surgery showed a strong association with AKI. Furthermore, determinants of kidney perfusion, namely CVP and arterial pressure are interdependent; as are constituents of stroke volume, that is, cardiac output and heart rate.

Cardiac Surgery-Associated Acute Kidney Injury in Neonates Undergoing the Norwood Operation: Retrospective Analysis of the Multicenter Neonatal and Pediatric Heart and Renal Outcomes Network Dataset, 2015-2018.

Cardiac surgery-associated acute kidney injury (CS-AKI) is associated with adverse outcomes. Single-center studies suggest that the prevalence of CS-AKI is high after the Norwood procedure, or stage 1 palliation (S1P), but multicenter data are lacking. A secondary analysis of the Neonatal and Pediatric Heart and Renal Outcomes Network (NEPHRON) multicenter cohort who underwent S1P. Using neonatal modification of Kidney Disease Improving Global Outcomes (KDIGO) criteria, perioperative associations between CS-AKI with morbidity and mortality were examined. Sensitivity analysis, with the exclusion of prophylactic peritoneal dialysis (PD) patients, was performed. Twenty-two hospitals participating in the Pediatric Cardiac Critical Care Consortium (PC 4 ) and contributing to NEPHRON. Three hundred forty-seven neonates (< 30 d old) with S1P managed between September 2015 and January 2018. None. Of 347 patients, CS-AKI occurred in 231 (67%). The maximum stages were as follows: stage 1, in 141 of 347 (41%); stage 2, in 51 of 347 (15%); and stage 3, in 39 of 347 (11%). Severe CS-AKI (stages 2 and 3) peaked on the first postoperative day. In multivariable analysis, preoperative feeding was associated with lower odds of CS-AKI (odds ratio [OR] 0.48; 95% CI, 0.27-0.86), whereas prophylactic PD was associated with greater odds of severe CS-AKI (OR 3.67 [95% CI, 1.88-7.19]). We failed to identify an association between prophylactic PD and increased creatinine (OR 1.85 [95% CI, 0.82-4.14]) but cannot exclude the possibility of a four-fold increase in odds. Hospital mortality was 5.5% ( n = 19). After adjusting for risk covariates and center effect, severe CS-AKI was associated with greater odds of hospital mortality (OR 3.67 [95% CI, 1.11-12.16]). We failed to find associations between severe CS-AKI and respiratory support or length of stay. The sensitivity analysis using PD failed to show associations between severe CS-AKI and outcome. KDIGO-defined CS-AKI occurred frequently and early postoperatively in this 2015-2018 multicenter PC 4 /NEPHRON cohort of neonates after S1P. We failed to identify associations between resource utilization and CS-AKI, but there was an association between severe CS-AKI and greater odds of mortality in this high-risk cohort. Improving the precision for defining clinically relevant neonatal CS-AKI remains a priority.

Decreased Intraoperative Renal Tissue Oxygenation after Cardiopulmonary Bypass Predicts Cardiac Surgery-Associated Acute Kidney Injury in Neonates.

(1) Background: Near-infrared spectroscopy (NIRS) is a noninvasive tool frequently used during cardiac surgery and postoperatively in the cardiac intensive care unit to monitor regional tissue oxygen saturation. A relationship between trends of intraoperative renal oxygenation and the risk of developing cardiac surgery-associated acute kidney injury (AKI) post-operatively has not yet been established in the neonatal population. The objective of this study is to evaluate the relationship of cerebral and renal oxygenation during cardiopulmonary bypass with cardiac surgery-associated AKI in the first 72 h post-operation in neonates < 30 days of age. (2) Methods: A prospective cohort study at a tertiary care children's hospital was performed. Renal and cerebral oxygenation measured were collected intraoperatively from neonates < 30 days of age who underwent cardiopulmonary bypass for the correction of congenital heart disease. AKI was defined accordance with the Kidney Disease: Improving Global Outcomes criteria modified for neonates. Variables were compared between groups. (3) Results: 32 neonates with 35 cardiopulmonary bypass cases were included. AKI was diagnosed in 60% of cases. Intra-operative renal oxygenation, both on- and off-bypass, did not differ among the three AKI groups (p > 0.19). Renal oxygenation after coming off, but not during, cardiopulmonary bypass steadily decreased with increasing levels of AKI (Jonckheere's test, one-sided p = 0.024). (4) Conclusions: Renal oxygenation decreased in proportion to AKI severity after coming off, but not during, cardiopulmonary bypass.

Protein Kinase N1 Level Predicts Acute Kidney Injury in Patients Undergoing Cardiac Surgery: A Prospective Cohort Study

Introduction: The objective of this study was to examine the utility of protein kinase N1 (PKN1) as a biomarker of cardiac surgery-associated AKI (CSA-AKI). Methods: A prospective cohort study of 110 adults undergoing on-pump cardiac surgery was conducted. The associations between post-operative PKN1 and CSA-AKI, AKI severity, need for renal replacement therapy (RRT), duration of AKI, length of ICU stay, and post-operative hospital stay were evaluated. Results: Patients were categorized into three groups according to PKN1 tertiles. The incidence of CSA-AKI in the third tertile was 3.4-fold higher than that in the first. PKN1 was an independent risk factor for CSA-AKI. The discrimination of PKN1 to CSA-AKI assessed by ROC curve indicated that the AUC was 0.70, and the best cutoff was 5.025 ng/mL. This group (>5.025 ng/mL) was more likely to develop CSA-AKI (p < 0.001). The combined AUC of EuroSCORE, aortic cross-clamp time, and PKN1 was 0.82 (p < 0.001). A higher level of PKN1 was related to increased need for RRT, longer duration of AKI, and length of ICU and post-operative hospital stays. Conclusions: PKN1 could be a potential biomarker for the prediction of CSA-AKI. The combination of PKN1, EuroSCORE, and aortic cross-clamp time was likely to predict the occurrence of CSA-AKI.