Around one-quarter of all patients undergoing cardiac procedures, particularly those on cardiopulmonary bypass, develop cardiac surgery-associated acute kidney injury (CSA-AKI). This complication increases the risk of several serious morbidities and of mortality, representing a significant burden for both patients and the healthcare system. Patients with diminished kidney function before surgery, such as those with chronic kidney disease, are at heightened risk of developing CSA-AKI and have poorer outcomes than patients without preexisting kidney injury who develop CSA-AKI. Several mechanisms are involved in the development of CSA-AKI; injury is primarily thought to result from an amplification loop of inflammation and cell death, with complement and immune system activation, cardiopulmonary bypass, and ischemia-reperfusion injury all contributing to pathogenesis. At present there are no effective, targeted pharmacological therapies for the prevention or treatment of CSA-AKI, although several preclinical trials have shown promise, and clinical trials are under way. Progress in the understanding of the complex pathophysiology of CSA-AKI is needed to improve the development of successful strategies for its prevention, management, and treatment. In this review, we outline our current understanding of CSA-AKI development and management strategies and discuss potential future therapeutic targets under investigation.

Dissociation between the micro- and macrocirculation as well as the lack of specificity of current markers to signal impaired tissue oxygenation complicate the timely diagnosis and treatment of tissue hypoperfusion to prevent acute kidney injury (AKI) after cardiac surgery. The newly developed non-invasive technique to measure the mitochondrial oxygenation (mitoPO2) is currently the most downstream bedside marker of tissue oxygenation. The aim was to investigate mitoPO2 as an early marker of postoperative development of AKI.

In a prospective observational study, postoperative mitochondrial oxygen tension was measured to detect AKI (defined by KDIGO) in patients undergoing cardiac surgery.

Of 50 included patients, 44 patients had analyzable mitoPO2 signal. 5 patients developed AKI. MitoPO2 at ICU admission was 16(13.8-24.6)mmHg in patients who developed AKI vs 63.4(37.5-77.9) mmHg in patients without AKI (p < 0.001). MitoPO2 predicted AKI (ROC 0.95 (0.89-1.0) with an optimal cut-off value of 30 mmHg (OR 4.4, CI 2.8-6.0, p < 0.001). Also, longer period of time under the mitoPO2 threshold predicted AKI with an AUROC of 0.91(0.80-1.00). In all patients, a decreased mitoPO2 occurred 4 h earlier than an clinically relevant increase in serum lactate. Other markers of tissue hypoperfusion, did not differ between patients with and without AKI.

A mitoPO2 value below 30 mmHg at ICU admission as well as the duration below this threshold indicate the development of AKI in cardiac surgery patients, occurring earlier than an increase in lactate above the normal range.

Acute kidney injury (AKI) following cardiac surgery is common and is associated with poor outcomes. The combination of urinary tissue inhibitor of metalloproteinase 2 (TIMP-2) and insulin-like growth factor-binding protein 7 (IGFBP7) is a strong predictor of AKI after cardiac surgery. However, most studies have focused on non-Asian populations, and comparisons with other AKI biomarkers or the optimal timing for measurement have yet to be explored.

We prospectively enrolled adult patients at Kochi Medical School Hospital in Kochi, Japan, to assess the predictive values of [TIMP-2]•[IGFBP7], TIMP-2, IGFBP7, neutrophil gelatinase-associated lipocalin (NGAL), and liver fatty acid-binding protein (L-FABP) measured preoperatively and at 2, 4, 6, and 8 h, as well as on day 1 and day 2 after postoperative intensive care unit (ICU) admission, using receiver operating characteristic curve (ROC) analysis.

Of the 38 patients, 13 (34.2%) developed AKI: seven (18.4%) with stage 1, four (10.5%) with stage 2, and two (5.2%) with stage 3. ROC analysis showed that the area under the curve (AUC) for predicting any stage of AKI peaked at 0-4 h, with the highest value at 2 h after ICU admission. Among the biomarkers, [TIMP-2]•[IGFBP7] showed the best AUC at 2 h after ICU admission, followed by TIMP-2, IGFBP7, L-FABP, and NGAL.

Our study demonstrated the good predictive performance of urine biomarkers, including [TIMP-2]•[IGFBP7], TIMP-2, IGFBP7, NGAL, and L-FABP, for any stage of cardiac surgery-associated AKI (CSA-AKI). The combination of TIMP-2 and IGFBP7 measured 2 h after postoperative ICU admission effectively predicted CSA-AKI, identifying patients at higher risk.

Sodium-glucose transporter-2 (SGLT2) inhibitors reduced the incidence of acute kidney injury in large cardiovascular outcome trials in patients with chronic heart and kidney failure. Acute kidney injury is a common complication following cardiac surgery. We hypothesized that perioperative SGLT2 inhibition could reduce kidney injury after cardiac surgery, measured with the biomarker neutrophil gelatinase-associated (NGAL).

In this open-label phase IV, randomized, parallel-group, pilot study, adult patients undergoing elective cardiac surgery with cardiopulmonary bypass were randomized to receive either an SGLT2 inhibitor, empagliflozin (10 mg; oral) once daily, from three days before surgery until postoperative day two, or standard-of-care. The primary outcome was the between-group difference of serum NGAL on the second postoperative day. Moreover, other biomarkers for acute kidney injury were measured, including serum kidney injury molecule-1 (KIM-1), hypoxia-inducible factor-1 alpha (HIF-1α), and urine NGAL/Creatinine and KIM-1/Creatinine ratios. Additional outcomes included acute kidney injury incidence within the first seven days following cardiac surgery according to Kidney Disease: Improving Global Outcomes criteria and metabolic parameters, including ketone body concentrations and glycemic control.

Between March 2022 and April 2023, 55 patients were included (sex: 73 % male, age: 66 ± 10 years, BMI: 28 ± 4 kg/m2, empagliflozin n = 25, control n = 30) in the intention-to-treat analysis. There were no significant between-group differences in serum and urine NGAL or KIM-1. However, empagliflozin significantly reduced the incidence of acute kidney injury (20 % vs 66.7 %; absolute difference 46.7 %, 95 % CI, -69.7 - -23.6; P < .001). A significant increase in serum HIF-1α after surgery was solely observed in the control group. We observed no between-group differences in the incidence of (euglycemic) ketoacidosis or hypoglycemic events.

In this pilot study, perioperative SGLT2 inhibition was not associated with lower NGAL levels. We observed that SGLT2 inhibition reduced the incidence of acute kidney injury in this small study population. As the results of this pilot study are hypotheses-generating, further validation is needed in a large-scale, double-blind, placebo-controlled, randomized trial, which is currently ongoing.

Background: Oxidative stress and systemic inflammation during cardiac surgery can lead to postoperative complications. Although vitamin C and thiamine (vitamin B1) have individually demonstrated protective effects, their combined effects remain underexplored. This study aimed to evaluate the efficacy of combined vitamin C and B1 therapy versus that of vitamin C alone in reducing inflammatory and cardiac biomarkers and improving postoperative outcomes in patients undergoing cardiac surgery. Methods: In this prospective, double-blind, randomized controlled trial, 64 patients scheduled for elective cardiac surgery at a tertiary care center were randomized to receive either 1000 mg vitamin C or a combination of 1000 mg vitamin C and 100 mg vitamin B1 at four perioperative time points. Primary outcomes included changes in inflammatory biomarkers [C-reactive protein, interleukin-6 (IL-6), and white blood cells], and cardiac biomarkers [creatine kinase-MB, Troponin-I, and lactate dehydrogenase]. Secondary outcomes included hemodynamic parameters and left ventricular function. Results: Compared with vitamin C alone, combined vitamin B1 and vitamin C significantly reduced postoperative cardiac biomarker levels. IL-6 levels were significantly lower immediately in the combined group; however, this effect was not sustained at 24 h post-surgery. Up to 24 h after surgery, no significant differences in hemodynamic stability or left ventricular ejection were observed between the groups. Notably, the combined therapy group demonstrated a lower incidence of postoperative arrhythmias and shorter dobutamine duration within 24 postoperatively. Conclusions: Combined vitamin C and B1 therapy significantly reduced markers of myocardial injury and early inflammatory responses (IL-6) in patients undergoing cardiac surgery, suggesting its potential as a protective agent.

To evaluate the efficacy of intravenous (IV) amino acids in preventing acute kidney injury (AKI) in patients undergoing cardiac surgery.

PubMed, EMBASE, and Cochrane Library databases were systematically searched for all relevant randomised controlled trials (RCTs) published from inception to July 25, 2024. A random effects model was used to pool the risk ratios (RR) for dichotomous outcomes, and the combined data was visually represented using forest plots.

3 studies involving 3646 patients were included in the meta-analysis. IV amino acids did not significantly lower the overall AKI incidence compared with control measures. However, they significantly reduced the risk of Stage 1 AKI and Stage 3 AKI. No differences were observed between intervention and control for Stage 2 AKI or need for kidney replacement therapy.

IV amino acids may offer protective benefits against severe AKI stages in cardiac surgery patients. Further studies are warranted to validate our findings.

Cardiac surgery-associated acute kidney injury (CSA-AKI) is a common complication of cardiac surgery and is associated with increased morbidity and mortality. Recent guidelines emphasize the need for new monitoring methods to facilitate targeted CSA-AKI prevention and treatment strategies. In vivo real-time measurement of mitochondrial oxygen tension (mitoPO2), could potentially fulfil this role during cardiac surgery, as suggested in our previous pilot study.

In this prospective observational study, we investigated 75 cardiac surgery patients with an increased preoperative CSA-AKI risk. The primary aim of this study was to assess whether patients who developed CSA-AKI experienced prolonged periods of mitoPO2 < 20 mmHg during surgery. mitoPO2 was measured intraoperatively, and CSA-AKI was defined according to the Kidney Disease: Improving Global Outcomes criteria. Four additional mitoPO2 thresholds (<25, <30, <35, and < 40 mmHg) were analyzed, including the predictive capacity of all thresholds for CSA-AKI.

This study found that patients who developed CSA-AKI had a significantly longer intraoperative time with mitoPO2 <20 mmHg and <25, <30, <35, and <40 mmHg. Subsequently, we tested all thresholds for their association with the risk of CSA-AKI, with the <25 mmHg threshold demonstrating the highest significant odds ratio. Every minute spent below <25 mmHg increased the risk of CSA-AKI by 0.7 % (P = 0.021).

This study highlighted the association between mitoPO2 and the onset of CSA-AKI. Extended durations below the mitoPO2 threshold of 25 mmHg significantly correlate with an elevated CSA-AKI risk. Using mitoPO2 as a monitoring tool shows promise in potentially predicting and possibly preventing CSA-AKI when used as a treatment trigger in cardiac surgery patients.

Acute kidney injury (AKI) often accompanies cardiac valve surgery, and worsens patient outcome. The aim of our study is to identify preoperative and intraoperative independent risk factors for AKI in patients undergoing cardiac valve surgery. Using these factors, we developed a risk prediction model for AKI after cardiac valve surgery and conducted external validation.

Our retrospective study recruited 497 adult patients undergoing cardiac valve surgery as a derivation cohort between February and August 2023. Patient demographics, including medical history and perioperative clinical information, were acquired, and patients were classified into one of two cohorts, AKI and non-AKI, according to the Kidney Disease: Improving Global Outcomes (KDIGO) guidelines. Using binary logistic stepwise regression analysis, we identified independent AKI risk factors after cardiac valve surgery. Lastly, we constructed a nomogram and conducted external validation in a validation cohort comprising 200 patients. The performance of the nomogram was evaluated based on the area under the receiver operating characteristic curve (AUC), calibration curves and decision curve analysis (DCA).

In the derivation cohort, 172 developed AKI (34.6%). Relative to non-AKI patients, the AKI patients exhibited elevated postoperative complication incidences and worse outcome. Based on multivariate analysis, advanced age (OR: 1.855; p = 0.011), preoperative hypertension (OR: 1.91; p = 0.017), coronary heart disease (OR: 6.773; p < 0.001), preoperative albumin (OR: 0.924; p = 0.015), D-Dimer (OR: 1.001; p = 0.038), plasma creatinine (OR: 1.025; p = 0.001), cardiopulmonary bypass (CPB) duration (OR: 1.011; p = 0.001), repeat CPB (OR: 6.195; p = 0.010), intraoperative red blood cell transfusion (OR: 2.560; p < 0.001), urine volume (OR: 0.406 p < 0.001) and vasoactive-inotropic score (OR: 1.135; p = 0.009) were independent risk factors for AKI. The AUC of the nomogram in the derivation and validation cohorts were 0.814 (95%CI: 0.775-0.854) and 0.798 (95%CI: 0.726-0.871), respectively. Furthermore, the calibration curve revealed that the predicted outcome was in agreement with the actual observations. Finally, the DCA curves showed that the nomogram had a good clinical applicability value.

Several perioperative factors modulate AKI development following cardiac valve surgery, resulting in poor patient prognosis. The proposed AKI predictive model is both sensitive and precise, and can assist in high-risk patient screening in the clinics.

Cardiac surgery-associated acute kidney injury (CSA-AKI) is a prevalent complication with poor outcomes, and its early prediction remains a challenging task. Currently available biomarkers for acute kidney injury (AKI) include serum cystatin C (sCysC) and urinary N-acetyl-β-D-glucosaminidase (uNAG). Widely used biomarkers for assessing cardiac function and injury are N-terminal pro B-type natriuretic peptide (NT-proBNP) and cardiac troponin I (cTnI). In light of this, our study aimed to evaluate the effectiveness of these four biomarkers in predicting CSA-AKI.

This prospective observational study enrolled adult patients who had undergone cardiac surgery. The clinical prediction model for CSA-AKI was developed using the least absolute shrinkage and selection operator (LASSO) regression method. The model's performance was assessed using the area under the curve of the receiver operating characteristic (ROC-AUC), decision curve analysis (DCA), and calibration curves. Furthermore, a separate validation cohort was constructed to externally validate the prediction model. Additionally, a risk nomogram was created to facilitate risk assessment and prediction.

In the modeling cohort consisting of 689 patients and the validation cohort consisting of 313 patients, the total incidence of CSA-AKI was 33.4%. The LASSO regression identified several predictors, including age, history of hypertension, baseline serum creatinine (sCr), coronary artery bypass grafting combined with valve surgery, cardiopulmonary bypass duration, preoperative albumin, hemoglobin, postoperative NT-proBNP, cTnI, sCysC, and uNAG. The constructed clinical prediction model demonstrated robust performance, with a ROC-AUC of 0.830 (0.800-0.860) in the modeling cohort and 0.840 (0.790-0.880) in the validation cohort. Furthermore, both calibration and DCA indicated good model fit and clinical benefit.

This study demonstrates that incorporating the immediately postoperative renal biomarkers, sCysC and uNAG, along with the cardiac biomarkers, NT-proBNP and cTnI, into a clinical early prediction model can significantly enhance the accuracy of predicting CSA-AKI. These findings suggest that a comprehensive approach combining both renal and cardiac biomarkers holds promise for improving the early detection and prediction of CSA-AKI.

Cardiac surgery is known to have high rates of perioperative red blood cell (RBC) transfusions which are associated with increased postoperative mortality and morbidity. Perioperative erythropoietin (EPO) has been suggested to lower perioperative RBC transfusions, and the effect on postoperative morbidity or mortality is unknown.

The registered study protocol is available on PROSPERO (CRD42022314538). We searched the Pubmed, EMbase, and Cochrane CENTRAL databases for randomized controlled trials (RCT) of EPO in cardiac surgery. Outcomes were short-term mortality, acute kidney injury (AKI), re-operation, cerebrovascular accident (CVA), perioperative myocardial infarction (MI), infectious complications, and RBC transfusions. RCT studies of perioperative EPO that reported at least one prespecified outcome of interest were included.

A total of 21 RCT's (n = 2,763 patients) were included. Mortality analysis included 17 studies (EPO 1,272 patients, control 1,235) and showed no significant difference (risk difference (RD) 0.0004, 95%CI: -0.016, 0.009). EPO did not reduce the incidence of AKI (RD -0.006, 95% CI: -0.038, 0.026) and reoperation (RD 0.001, 95% CI: -0.013, 0.015). The incidence of CVA (RD -0.004, 95% CI: -0.015, 0.007) and perioperative MI (RD -0.008, 95% CI: -0.021, 0.005) was similar between the groups.

Although EPO had been proven to reduce perioperative RBC transfusions, we did not find that it reduces the incidence of postoperative short-term mortality, AKI, and reoperation. The study results support that perioperative EPO is also safe, with no rise in thrombotic events, including CVA and perioperative MI.

Background: Infective endocarditis (IE) poses significant challenges in cardiovascular medicine, often necessitating valvular surgery to manage severe complications. Postoperative acute kidney injury (AKI) is a notable complication affecting patient outcomes. While clinical and procedural factors have been well studied, the role of radiological renal artery parameters in AKI risk remains underexplored. Methods: This retrospective study analyzed 80 patients with IE who underwent valvular surgery from 2013 to 2021, focusing on postoperative AKI as defined by the Kidney Disease: Improving Global Outcomes (KDIGO) criteria. Radiological parameters, including renal artery calcification, renal ostial calcification, the presence of renal infarctions, and additional arteries, were assessed using preoperative computed tomography (CT). Statistical analyses included binary logistic and linear regression models, Kaplan-Meier survival curves, and Cox proportional hazard regression to explore associations between these parameters and AKI incidence, creatinine levels, and mortality. Results: Out of 80 patients, 31 (38.8%) developed AKI. No significant differences were found in baseline characteristics or radiological parameters between the AKI+ and AKI- groups. Binary logistic and linear regression analyses revealed no substantial relationship between anatomical factors and AKI risk or creatinine levels. However, Cox regression identified "additional renal artery" as a significant predictor of 1-month mortality (HR: 1.747, 95% CI: 1.024-2.979, p = 0.041) but not for 6- or 12-month mortality. Conclusions: Radiological anatomical factors, including calcifications and additional arteries, did not significantly impact AKI risk in IE patients undergoing valvular surgery. However, the presence of additional arteries was associated with increased short-term mortality. These findings suggest the need for further research to elucidate factors contributing to AKI and mortality in this context.

To investigate whether postoperative systemic immune-inflammation index (SII) is associated with acute kidney injury (AKI) after cardiac surgery.

We included patients undergoing cardiac surgery from the Medical Information Mart for Intensive Care-Ⅳ database to conduct a retrospective cohort study. The outcomes are AKI, severe AKI, and 30-day mortality after cardiac surgery. Analytical techniques including receiver operating characteristic (ROC) analysis, restricted cubic splines (RCS), and multivariable logistic regression were used to assess the association between SII and outcomes. Sensitivity analyses using inverse probability of treatment weighting (IPTW) and the E-value were conducted to validate the stability of the results.

3,799 subjects were included in this study. We used ROC to calculate an optimal cutoff value for predicting AKI after cardiac surgery, and subsequently patients were divided into two groups based on the cutoff value (Low SII: ≤ 949 × 109/L; High SII: > 949 × 109/L). ROC showed moderately good performance of SII for predicting AKI, while RCS also indicated a positive association between SII and AKI. The multivariate logistic analysis further affirmed the heightened risk of AKI in patients in the high SII group (OR, 5.33; 95%CI, 4.34-6.53; P < 0.001). Similar associations were observed between SII and severe AKI. Sensitivity and subgroup analyses indicated the robustness of the findings.

Elevated SII was independently associated with a higher risk of AKI in adults undergoing cardiac surgery. The potential causal relationship between postoperative SII and cardiac surgery associated AKI warrants prospective research.

Remote ischemic preconditioning (RIPC) has 2 time windows for organ protection: acute and delayed. Previous studies have mainly focused on the organoprotective effects of acute RIPC. We aimed to determine whether delayed RIPC can reduce the occurrence of acute kidney injury (AKI) and postoperative complications in patients undergoing cardiac surgery.

This prospective, single-center, double-blind, randomized controlled trial involved 509 patients at high risk for AKI who were scheduled for elective cardiac surgery requiring cardiopulmonary bypass. Patients were randomized to receive RIPC (4 cycles of 5-minute inflation and 5-minute deflation on 1 upper arm with a blood pressure cuff) 24 hours before surgery or a sham condition (control group) that was induced by 4 cycles of 5-minute inflation to a pressure of 20 mm Hg followed by 5-minute cuff deflation. The primary end point was the incidence of AKI within the prior 7 days after cardiac surgery. The secondary end points included renal replacement therapy during hospitalization, change in urinary biomarkers of AKI and markers of myocardial injury, duration of intensive care unit stay and mechanical ventilation, and occurrence of nonfatal myocardial infarction, stroke, and all-cause mortality by day 90.

A total of 509 patients (mean age, 65.2±8.2 years; 348 men [68.4%]) were randomly assigned to the RIPC group (n=254) or control group (n=255). AKI was significantly reduced in the RIPC group compared with the control group (69/254 [27.2%] versus 90/255 [35.3%]; odds ratio, 0.68 [95% CI, 0.47-1.00]; P=0.048). There were no significant between-group differences in the secondary end points of perioperative myocardial injury (assessed by the concentrations of cardiac troponin T, creatine kinase myocardial isoenzyme, and NT-proBNP [N-terminal pro-brain natriuretic peptide]), duration of stay in the intensive care unit and hospital, and occurrence of nonfatal myocardial infarction, stroke, and all-cause mortality by day 90.

Among high-risk patients undergoing cardiac surgery, delayed RIPC significantly reduced the occurrence of AKI.

URL: https://www.chictr.org.cn; Unique identifier: ChiCTR2000035568.

Acute kidney injury (AKI) is defined and staged by reduced urine output (UO) and increased serum creatinine (SCr). UO is typically measured manually and documented in the electronic health record, making early and reliable detection of oliguria-based AKI and electronic data extraction challenging. The authors investigated the diagnostic performance of continuous UO, enabled by active drain line clearance-based alerts (Accuryn AKI Alert), compared with AKI stage 2 SCr criteria and their associations with length of stay, need for continuous renal replacement therapy, and 30-day mortality.

This study was a prospective and retrospective observational study.

Nine tertiary centers participated.

Cardiac surgery patients were enrolled.

None.

A total of 522 patients were analyzed. AKI stages 1, 2, and 3 were diagnosed in 32.18%, 30.46%, and 3.64% of patients based on UO, compared with 33.72%, 4.60%, and 3.26% of patients using SCr, respectively. Continuous UO-based alerts diagnosed stage ≥1 AKI 33.6 (IQR =15.43, 95.68) hours before stage ≥2 identified by SCr criteria. A SCr-based diagnosis of AKI stage ≥2 has been designated a Hospital Harm by the Centers for Medicare & Medicaid Services. Using this criterion as a benchmark, AKI alerts had a discriminative power of 0.78. The AKI Alert for stage 1 was significantly associated with increased intensive care unit and hospital length of stay and continuous renal replacement therapy, and stage ≥2 alerts were associated with mortality.

AKI Alert, based on continuous UO and enabled by active drain line clearance, detected AKI stages 1 and 2 before SCr criteria. Early AKI detection allows for early kidney optimization, potentially improving patient outcomes.

Hypertrophic 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 of this work were to evaluate the prevalence of CSA-AKI after septal myectomy and identify potential perioperative and phenotype-related factors contributing to CSA-AKI.

This was a retrospective database analysis with new data analysis.

The study occurred in a single university academic expertise center for septal myectomy HOCM patients.

Data from 238 HOCM patients with septal myectomy operated on between 2005 and 2022 were collected.

CSA-AKI was stratified according to the Kidney Disease: Improving Global Outcomes (KDIGO) guidelines using measurement of creatinine and urine production. Important HOCM phenotype-related and perioperative factors were analyzed for their possible associations with CSA-AKI.

CSA-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 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.

CSA-AKI is a common complication after septal myectomy but was transient, and kidney function recovered in all patients.

Renal failure after cardiac surgery is associated with increased morbidity and mortality. There is a lack of data examining the rate of renal recovery after patients have started dialysis following cardiac surgery. We aimed to determine the frequency of and time to renal recovery of patients requiring dialysis after cardiac surgery.

All patients who developed new-onset renal failure requiring dialysis following cardiac surgery at our institution from 2011 to 2022 were included. Renal recovery, time to renal recovery, and mortality at 1 year were merged with patients' Society of Thoracic Surgeons Adult Cardiac Surgery Database files. Kaplan-Meier analysis was used to predict time to renal recovery; we censored patients who died or were lost to follow up. Cox regression was used for risk-adjustment.

A total of 312 patients were included in the final analysis. Mortality during index hospital admission was 33% (n = 105), and mortality at 1 year was 45% (n = 141). Of those surviving at 1 year, 69% (n = 118) remained renally recovered. Median renal recovery time was 56 (37-74) days. Accounting for mortality as a competing risk, 51% of patients were predicted to achieve renal recovery. Increasing age (hazard ratio, 0.98; 0.514-0.94, P < .026) and increasing total packed red blood cells (hazard ratio, 0.0958; 0.937-0.987, P < .001) received were found to be significant negative predictors of renal recovery in the Fine-Gray model for subhazard distribution.

More than two-thirds of patients with renal failure who survived the perioperative period had renal recovery within 1 year after surgery. Recovery was driven primarily by postoperative complications rather than comorbidities and intraoperative factors, suggesting renal failure in the postoperative cardiac surgery patient surviving to discharge is unlikely to be permanent.

There is little known about the contribution of exosomal microRNAs (exomiRs) in the children's cardiac surgery-associated acute kidney injury (CSA-AKI). This study aimed to find diagnostic biomarkers for predicting CSA-AKI in children. A prospective observational study was conducted from April 2020 to March 2021.According to the changes of serum creatinine (SCr) value and urine volume within 48 h, the children were divided into acute kidney injury (AKI) group and non-AKI group. Serum samples were collected 4 h after cardiac surgery. Isolation of extracellular vesicles (EVs) and extraction of exomiRs from serum samples. Illumina high-throughput sequencing was used to quantify exomiRs and screen candidate microRNAs (miRNAs). Expression levels of candidate miRNAs were validated using droplet digital polymerase chain reaction (ddPCR). Normal and injuried rats' kidney tissue were collected for tissue validation. In the pre-experimental stage (4 AKI vs. 4 non-AKI), hsa-miR-184, hsa-miR-4800-3p, hsa-miR-203a-3p and hsa-miR-6766-3p were selected as candidate genes. In the verification stage (8 AKI vs. 12 non-AKI), the expression of hsa-miR-184 in AKI group was significantly lower than that in non-AKI group (P = 0.031), and the expression of hsa-miR-4800-3p and hsa-miR-6766-3p in AKI group was significantly higher than that in non-AKI group (P = 0.01 and P = 0.047). There was no significant difference in the expression of hsa-miR-203a-3p between the two groups (P > 0.05). The expression of rats' kidney tissue rno-miR-184 in AKI group was significantly lower than that in the normal group (P = 0.044). The area under the curve (AUC) of AKI predicted by hsa-miR-184 is 0.7865 and the AUC of hsa-miR-6766-3p is 0.7708. Combined with two kinds of miRNAs, the area under the curve of AKI is predicted to be 0.8646. The change of exomiRs level in circulatory system occurred in the early stage after cardiac operation, and the changes of hsa-miR-184 and hsa-miR-6766-3p content in circulatory system could predict CSA-AKI well.

Acute kidney injury (AKI) is a common complication after on-pump cardiac surgery, and previous studies have suggested that blood glucose is associated with postoperative AKI. However, limited evidence is available regarding intraoperative glycemic thresholds in cardiac surgery. The aim of this study was to explore the association between peak intraoperative blood glucose and postoperative AKI, and determine the cut-off values for intraoperative glucose concentration associated with an increased risk of AKI.

The study was retrospective and single-centered. Adult patients in West China Hospital of Sichuan University who underwent on-pump cardiac surgery (n = 3375) were included. The primary outcome was the incidence of AKI. Multivariable logistic analysis using restricted cubic spline was performed to explore the association between intraoperative blood glucose and postoperative AKI.

The incidence of AKI in the study population was 18.0% (607 of 3375). Patients who developed AKI had a significantly higher peak intraoperative glucose during the surgery compared to those without AKI. After adjustment for confounders, the incidence of AKI increased with peak intraoperative blood glucose (adjusted odds ratio, 1.08, 95% confidence interval 1.03, 1.12). Furthermore, it was demonstrated that the possibility of AKI was relatively flat till 127.8 mg/dL (7.1 mmol/L) glucose levels which started to rapidly increase afterward.

Increased intraoperative blood glucose was associated with an increased risk of AKI. Among patients undergoing on-pump cardiac surgery, avoiding a high glucose peak (i.e., below 127.8 mg/dL [7.1 mmol/L]) may reduce the risk of postoperative AKI.

The cardiac surgery-associated acute kidney injury (CSA-AKI) occurs in up to 1 out of 3 patients. Off-pump coronary artery bypass grafting (OPCABG) is one of the major cardiac surgeries leading to CSA-AKI. Early identification and timely intervention are of clinical significance for CSA-AKI. In this study, we aimed to establish a prediction model of off-pump coronary artery bypass grafting-associated acute kidney injury (OPCABG-AKI) after surgery based on machine learning methods.

The preoperative and intraoperative data of 1,041 patients who underwent OPCABG in Chest Hospital, Tianjin University from June 1, 2021 to April 30, 2023 were retrospectively collected. The definition of OPCABG-AKI was based on the 2012 Kidney Disease Improving Global Outcomes (KDIGO) criteria. The baseline data and intraoperative time series data were included in the dataset, which were preprocessed separately. A total of eight machine learning models were constructed based on the baseline data: logistic regression (LR), gradient-boosting decision tree (GBDT), eXtreme gradient boosting (XGBoost), adaptive boosting (AdaBoost), random forest (RF), support vector machine (SVM), k-nearest neighbor (KNN), and decision tree (DT). The intraoperative time series data were extracted using a long short-term memory (LSTM) deep learning model. The baseline data and intraoperative features were then integrated through transfer learning and fused into each of the eight machine learning models for training. Based on the calculation of accuracy and area under the curve (AUC) of the prediction model, the best model was selected to establish the final OPCABG-AKI risk prediction model. The importance of features was calculated and ranked by DT model, to identify the main risk factors.

Among 701 patients included in the study, 73 patients (10.4%) developed OPCABG-AKI. The GBDT model was shown to have the best predictions, both based on baseline data only (AUC =0.739, accuracy: 0.943) as well as based on baseline and intraoperative datasets (AUC =0.861, accuracy: 0.936). The ranking of importance of features of the GBDT model showed that use of insulin aspart was the most important predictor of OPCABG-AKI, followed by use of acarbose, spironolactone, alfentanil, dezocine, levosimendan, clindamycin, history of myocardial infarction, and gender.

A GBDT-based model showed excellent performance for the prediction of OPCABG-AKI. The fusion of preoperative and intraoperative data can improve the accuracy of predicting OPCABG-AKI.

Cardiac surgery-associated acute kidney injury (CSA-AKI) affects up to 42% of cardiac surgery patients. CSA-AKI is multifactorial, with low abdominal perfusion pressure often overlooked. Abdominal perfusion pressure is calculated as mean arterial pressure minus intra-abdominal pressure (IAP). IAH decreases cardiac output and compresses the renal vasculature and renal parenchyma. Recent studies have highlighted the frequent occurrence of IAH in cardiac surgery patients and have linked the role of low perfusion pressure to the occurrence of AKI. This review and expert opinion illustrate current evidence on the pathophysiology, diagnosis, and therapy of IAH and ACS in the context of AKI.

Although loop diuretics (LDs) have been widely used in clinical practice, their effect on mortality when administered to patients experiencing cardiac surgery-associated acute kidney injury (CS-AKI) remains unknown. The study aimed to investigate the effectiveness of LD use in patients with CS-AKI.

Patients who underwent cardiac surgery with AKI were identified from the Medical Information Mart for Intensive Care III. Postoperative LD use in intensive care units (ICUs) was exposure. There were 2 primary outcome measures, the in-hospital mortality and ICU mortality; both were treated as time-to-event data and were analyzed via multivariable Cox proportional hazard models. Inverse probability weighting (IPW) was used to minimize bias.

The study enrolled a total of 5478 patients, with a median age of 67 years, among which 2205 (40.3%) were women. The crude in-hospital and ICU mortality rates were significantly lower in the LD use group (525 of 4150 [12.7%] vs 434 of 1328 [32.7%], P < .001; 402 of 4150 [9.69%] vs 333 of 1328 [25.1%], P < .001). Adjusted hazard ratios suggested significant reductions in both in-hospital (hazard ratio [HR], 0.428; 95% confidence interval [CI], 0.374-0.489) and ICU mortality (HR, 0.278; 95% CI, 0.238-0.327). The IPW data showed a similar reduction, in-hospital mortality (HR, 0.434; 95% CI, 0.376-0.502) and ICU mortality (HR, 0.296; 95% CI, 0.251-0.349). Such association may act differently for patients with different fluid balance ( P value for interaction < .001).

LD use is associated with lower hospital and ICU mortality in CS-AKI patients in general. Patients under different conditions showed diverse responses toward such treatment indicating that personalized management is needed.

Incidence and outcomes of acute kidney injury (AKI) among neonates who underwent open-heart surgery are not well highlighted in the literature. We aim to assess the incidence, risk factors, and outcome of AKI among neonates undergoing open-heart surgery.

This is a retrospective cohort study between 2016 and 2021 for all neonates requiring open heart surgery. The cases were divided into 2 groups: the AKI (index) group and the non-AKI (control) group. The two groups were statistically compared for risk factors, needs for dialysis, and outcomes.

100 patients fulfilled the inclusion criteria. Among them, 74 (74%) developed AKI, including 41 (55%), 15 (21%), and 18 (24%) patients in KDIGO stages 1, 2, and 3, respectively. Multivariate analysis comparing both groups demonstrated that low pre-operative creatinine (p = 0.01), prolonged bypass time (p = 0.0004) and high vasoactive inotropic score (VIS), (p = 0.0008) were risk factors for developing AKI post-operatively. Furthermore, in the AKI group, 17 (23%) neonates required renal replacement therapy in the form of peritoneal dialysis. The length of stay was higher in the AKI index group (p = 0.015). Patients who had AKI recovered their kidney function at discharge. There was no difference in mortality between both groups.

The AKI occurred in 74% of neonates undergoing open-heart surgery, with 23% of them needing peritoneal dialysis. Low pre-operative creatinine, high VIS score, and prolonged bypass time are potential risk factors for AKI development after neonatal open-heart surgery. AKI may lead to prolonged hospitalization, though most affected patients recovered their normal kidney function at discharge.

Cardiac surgery-associated (CSA) acute kidney injury (AKI) is a severe postoperative complication in patients undergoing off-pump coronary artery bypass grafting (OPCAB). Early detection of postoperative CSA-AKI may be key to improving patient outcomes. This study explored the use of renal biomarkers measured immediately after surgery for the early detection of CSA-AKI in patients undergoing OPCAB.

In all, 111 patients who underwent OPCAB at Kumamoto University Hospital between June 2020 and October 2022 were included in this study. Urinary neutrophil gelatinase-associated lipocalin, liver-type fatty acid-binding protein, and N-acetyl-β-D-glucosaminidase (NAG) were measured upon arrival in the intensive care unit (ICU) after surgery. AKI was diagnosed using KDIGO criteria. Of the 111 patients, 32 (28.8%) developed postoperative AKI. Regarding AKI staging, 19 (59.4%), 11 (34.4%), and 2 (6.3%) patients had Stage 1, 2, and 3 AKI, respectively. There were significant differences in chronic kidney disease, preoperative estimated glomerular filtration rate (eGFR), and NAG between the AKI and non-AKI groups. Multivariate analysis showed that preoperative eGFR (odds ratio [OR] for 5-mL/min/1.73 m2increase in eGFR 0.75; 95% confidence interval [CI] 0.63-0.89) and increasing urinary NAG concentrations at ICU admission (OR 2.44; 95% CI 1.30-4.60) were significant risk factors for CSA-AKI in OPCAB patients.

NAG and eGFR may be valuable biomarkers for the early detection of CSA-AKI in patients undergoing OPCAB.

Acute Kidney Injury (AKI) is a common complication after cardiac surgery and has been associated with poor outcomes. Dexmedetomidine (DEX) has been shown to confer direct renoprotection based on some animal and clinical studies, but data from other trials came to the opposite conclusion following cardiac surgery. This meta-analysis was conducted to evaluate the effects of perioperative DEX administration on the occurrence of AKI and the outcomes after cardiac surgery.

We searched databases including EMBASE, PubMed, and Cochrane CENTRAL for Randomized Controlled Trials (RCTs) focused on DEX for AKI in adult patients after cardiac surgery. The primary outcome was incidence of AKI. Secondary outcomes were Mechanical Ventilation (MV) duration, Intensive Care Unit (ICU) Length Of Stay (LOS), hospital LOS and mortality.

Fifteen trials enrolling 2907 study patients were collected in the meta-analyses. Compared with controls, DEX reduced the incidence of postoperative AKI (Odds Ratio [OR = 0.66]; 95% Confidence Interval [95% CI 0.48-0.91]; p = 0.01), and there was no significant difference between groups in postoperative mortality (OR = 0.63; 95% CI 0.32-1.26; p = 0.19), MV duration (Weighted Mean Difference [WMD = -0.44]; 95% CI -1.50-0.63; p = 0.42), ICU LOS (WMD = -1.19; 95% CI -2.89-0.51; p = 0.17), and hospital LOS (WMD = -0.31; 95% CI -0.76-0.15; p = 0.19).

Perioperative DEX reduced the incidence of postoperative AKI in adult patients undergoing cardiac surgery. No significant decrease existed in mortality, MV duration, ICU LOS and hospital LOS owing to DEX administration.

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).

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.

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.

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.

Despite the long-lasting notion about the substantial contribution of intraoperative un-stabilization of homeostasis factors on the incidence on acute kidney injury (AKI), the possible influence of intraoperative glucose or lactate management, as a modifiable factor, on the development of AKI remains inconclusive.

To investigated the relationship between intraoperative hyperglycemia, hyperlactatemia, and postoperative AKI in cardiac surgery.

A retrospective cohort study was conducted among 4,435 adult patients who underwent on-pump cardiac surgery from July 2019 to March 2022. Intraoperative hyperglycemia and hyperlactatemia were defined as blood glucose levels >10 mmol/L and lactate levels >2 mmol/L, respectively. The primary outcome was the incidence of AKI. All statistical analyses, including t tests, Wilcoxon rank sum tests, chi-square tests, Fisher's exact test, Kolmogorov-Smirnov test, logistic regression models, subgroup analyses, collinearity analysis, and receiver operating characteristic analysis, were performed using the statistical software program R version 4.1.1.

Among the 4,435 patients in the final analysis, a total of 734 (16.55%) patients developed AKI after on-pump cardiac surgery. All studied intraoperative metabolic disorders was associated with increased AKI risk, with most pronounced odds ratio (OR) noted for both hyperglycemia and hyperlactatemia were present intraoperatively [adjusted OR 3.69, 95% confidence intervals (CI) 2.68-5.13, p < 0.001]. Even when hyperglycemia or hyperlactatemia was present alone, the risk of postoperative AKI remained elevated (adjusted OR 1.97, 95% CI 1.50-2.60, p < 0.001).

The presence of intraoperative hyperglycemia and hyperlactatemia may be associated with postoperative acute kidney injury (AKI) in patients undergoing on-pump cardiac surgery. Proper and timely interventions for these metabolic disorders are crucially important in mitigating the risk of AKI.

Plasma viscosity (PV) is a key factor in microcirculatory flow resistance and capillary perfusion during hemodilution, we hypothesized a possible relationship between cardiac surgery-associated acute kidney injury (CSA-AKI) and PV. We conducted a prospective, observational, single-center study on 50 adult cardiac surgery patients with cardiopulmonary bypass (age 64 years, male sex 80%, baseline serum creatinine 1.04 mg/dL). We assessed perioperative characteristics, management, short-term outcomes, blood analysis, PV, serum creatinine, and diuresis. CSA-AKI was identified using KDIGO criteria. Data were collected at 10 time points during the first perioperative week. CSA-AKI occurred in 17 patients (34%): 12 (24%) stage 1, 1 (2%) stage 2, and 4 (8%) stage 3. Most patients (88%) developed CSA-AKI within 48 h post-surgery. Patients with CSA-AKI had higher body mass index (BMI), more frequent chronic kidney disease (CKD), and lower hemoglobin and hematocrit levels. The median baseline PV for the entire cohort was 1.50 cP on EDTA and 1.37 cP on citrate. No significant differences in PV levels were found between patients with CSA-AKI and normal kidney function, both at baseline and at the 48-h. Logistic and Cox regression analyses showed no significant relationship between PV and CSA-AKI. However, CSA-AKI was related to increased BMI, lower hemoglobin and hematocrit levels, and pre-existing CKD. The present study found no significant association between PV and CSA-AKI. Nevertheless, more research is needed to validate this finding and to investigate the role of PV in other clinical settings.

Myocardial protection and specifically cardioplegia have been extensively investigated in the beginnings of cardiac surgery. After cardiopulmonary bypass had become routine, more and more cardiac operations were possible, requiring reliable and reproducible protection for times of blood flow interruptions to the most energy-demanding organ of the body. The concepts of hypothermia and cardioplegia evolved as tools to extend cardiac ischaemia tolerance to a degree considered safe for the required operation. A plethora of different solutions and delivery techniques were developed achieving remarkable outcomes with cross-clamp times of up to 120 min and more. With the beginning of the new millennium, interest in myocardial protection research declined and, as a consequence, conventional cardiac surgery is currently performed using myocardial protection strategies that have not changed in decades. However, the context, in which cardiac surgery is currently performed, has changed during this time. Patients are now older and suffer from more comorbidities and, thus, other organs move more and more into the centre of risk assessment. Yet, systemic effects of cardioplegic solutions have never been in the focus of attention. They say hindsight is always 20-20. We therefore review the biochemical principles of ischaemia, reperfusion and cardioplegic extension of ischaemia tolerance and address the concepts of myocardial protection with 'hindsight from the 2020s'. In light of rising patient risk profiles, minimizing surgical trauma and improving perioperative morbidity management becomes key today. For cardioplegia, this means accounting not only for cardiac, but also for systemic effects of cardioplegic solutions.

Cardiac surgery-associated acute kidney injury is a common post-operative complication, mostly due to increasing oxidative stress. Recently, molecular hydrogen (H2 gas) has also been applied to cardiac surgery due to its ability to reduce oxidative stress. We evaluated the potential effect of H2 application on the kidney in an in vivo model of simulated heart transplantation. Pigs underwent cardiac surgery within 3 h while connected to extracorporeal circulation (ECC) and subsequent 60 min of spontaneous reperfusion of the heart. We used two experimental groups: T-pigs after transplantation and TH-pigs after transplantation treated with 4% H2 mixed with air during inhalation of anesthesia and throughout oxygenation of blood in ECC. The levels of creatinine, urea and phosphorus were measured in plasma. Renal tissue samples were analyzed by Western blot method for protein levels of nuclear factor erythroid 2-related factor 2 (Nrf2), Kelch-like ECH-associated protein 1 (Keap-1), and superoxide dismutase (SOD1). After cardiac surgery, selected plasma biomarkers were elevated. However, H2 therapy was followed by the normalization of all these parameters. Our results suggest activation of Nrf2/Keap1 pathway as well as increased SOD1 protein expression in the group treated with H2. The administration of H2 had a protective effect on the kidneys of pigs after cardiac surgery, especially in terms of normalization of plasma biomarkers to control levels.

Aortic dissection (AD) is a severe cardiovascular condition that could have negative consequences. Our study employed a prospective design and examined preoperative, perioperative, and postoperative data to evaluate the effects of gender on various medical conditions. We looked at how gender affected the results of aortic dissection (AD). In contrast to female patients who had more systemic hypertension (p=0.031), male patients had higher rates of hemopericardium (p=0.003), pulmonary hypertension (p=0.039), and hemopericardium (p=0.003). Dobutamine administration during surgery significantly raised the mortality risk (p=0.015). There were noticeably more women patients (p=0.01) in the 71 to 80 age group. Significant differences in age (p=0.004), eGFR at admission (p=0.009), and eGFR at discharge (p=0.006) were seen, however, there was no association between gender and mortality. In conclusion, our findings highlight that gender may no longer be such an important aspect of aortic dissection disease as we previously thought, and this information could have an important contribution for surgeons as well as for anesthesiologists involved in the management of acute aortic dissection.

Trace elements are essential micronutrients that take part in most antioxidant reactions in the body. In this study, we evaluated the levels of copper, chromium, manganese, selenium, magnesium, zinc, iron, and silicon in adult patients who undergone isolated on-pump coronary artery bypass with the occurrence of postoperative atrial fibrillation, transient renal injury, transient liver injury, and rate of wound infection; 51 adult patients (41 men, 10 women) underwent isolated coronary artery bypass grafting (CABG) under cardiopulmonary bypass. The mean age was 61,9 ± 8,0 years (range 45-82 years). Blood samples were collected preoperatively, postoperative first hour, postoperative first day, and fifth postoperative day for element analysis. Serum levels were determined by an Inductive Coupled Plasma Optical Emission Spectrometer (ICAP 6000). Serum copper, zinc, and selenium values, typically known as strong antioxidant elements in the body, decreased significantly during the first hour and first day of postoperative period compared to the preoperative period (p < 0.05). Also, postoperative atrial fibrillation, transient renal injury, transient liver injury, and rate of wound infection were observed to increase with the decrease in levels of trace elements (p < 0.05). The levels of these elements were observed to return to normal levels during the fifth postoperative day. The levels of trace elements decrease significantly after on-pump coronary artery bypass surgery. Our study results suggest that this could be one of the predisposing factors for increased postoperative atrial fibrillation, transient kidney injury, transient renal injury, and increased rate of wound infections for patients undergoing on-pump coronary artery bypass grafting.

Postoperative acute kidney injury (AKI) is a common complication and is associated with increased hospital length of stay and 30 day all-cause mortality. Unfortunately, we have neither a defined strategy to prevent AKI nor an effective treatment. In vitro, animal, and human studies have suggested that dexmedetomidine may have a renoprotective effect. We conducted a retrospective cohort study to evaluate if intraoperative dexmedetomidine was associated with a reduced incidence of AKI.

We collected data from 6625 patients who underwent major non-cardiothoracic cancer surgery. Before and after propensity score matching, we compared the incidence of postoperative AKI in patients who received intraoperative dexmedetomidine and those who did not. AKI was defined according to the Kidney Disease Improving Global Outcomes (creatinine alone values) criteria and calculated for postoperative Days 1, 2, and 3.

Twenty per cent (n=1301) of the patients received dexmedetomidine. The mean [standard deviation] administered dose was 78 [49.4] mcg. Patients treated with dexmedetomidine were matched to those who did not receive the drug. Patients receiving dexmedetomidine had a longer anaesthesia duration than the non-dexmedetomidine group. The incidence of AKI was not significantly different between the groups (dexmedetomidine 8% vs no dexmedetomidine 7%; P=0.333). The 30 day rates of infection, cardiovascular complications, or reoperation attributable to bleeding were higher in patients treated with dexmedetomidine. The 30 day mortality rate was not statistically different between the groups.

The administration of dexmedetomidine during major non-cardiothoracic cancer surgery is not associated with a reduction in AKI within 72 h after surgery.

The purpose of this study was to describe the longitudinal dynamic hemoglobin trajectories in patients undergoing cardiac surgery and to explore whether they provide a broader perspective in predicting AKI compared to traditional threshold values. Additionally, the interaction of red blood cell transfusion was also investigated.

The MIMIC-IV database was searched to identify patients undergoing cardiac surgery with cardiopulmonary bypass. Group-based trajectory modeling (GBTM) was used to determine the hemoglobin trajectories in the first 72 h after ICU admission. The correlation between hemoglobin trajectories and AKI was evaluated using multivariable logistic regression and inverse probability of treatment weighting. Receiver operating characteristic (ROC) curves were created in the dataset to further validate previously reported thresholds.

A total of 4,478 eligible patients were included in this study. Three hemoglobin trajectories were identified by GBTM, which were significantly different in the initial hemoglobin level and evolution pattern. Compared to the "the lowest, rising, and then declining" trajectory, patients in the "the highest, declining" and "medium, declining" trajectory groups had significantly lower AKI risk (OR 0.56; 95% CI 0.48, 0.67) and (OR 0.70; 95% CI 0.55, 0.90), respectively. ROC analysis yielded a disappointing result, with an AUC of 0.552, sensitivity of 0.25, and specificity of 0.86 when the hemoglobin threshold was set at 8 g/dl in the entire cohort. In the subgroup analysis of red blood cell transfusion, hemoglobin levels above 10 g/dl predicted higher AKI risk, and there was no correlation between hemoglobin trajectories and AKI in the non-red blood cell transfusion subgroup.

This study identified a hemoglobin trajectory that is associated with an increased risk of AKI after cardiac surgery. It is noteworthy that fixed hemoglobin thresholds should not be applied to all patient types. In patients receiving red blood cell transfusion, maintaining hemoglobin levels above 10 g/dl through transfusion was associated with an increased risk of AKI.

Evaluating patients' risk for acute kidney injury (AKI) is crucial for positive outcomes following cardiac surgery. Our aims were first to select candidate risk factors from pre- or intra-operative real-world parameters collected from routine medical care and then evaluate potential associations between those parameters and risk of onset of post-operative cardiac surgery-associated AKI (CSA-AKI).

We conducted two cohort studies in Japan. The first was a single-center prospective cohort study (n = 145) to assess potential association between 115 clinical parameters collected from routine medical care and CSA-AKI (≥ Stage1) risk in the population of patients undergoing cardiac surgery involving cardiopulmonary bypass (CPB). To select candidate risk factors, we employed random forest analysis and applied survival analyses to evaluate association strength. In a second retrospective cohort study, we targeted patients undergoing cardiac surgery with CPB (n = 619) and evaluated potential positive associations between CSA-AKI incidence and risk factors suggested by the first cohort study.

Variable selection analysis revealed that parameters in clinical categories such as circulating inflammatory cells, CPB-related parameters, ventilation, or aging were potential CSA-AKI risk factors. Survival analyses revealed that increased counts of pre-operative circulating monocytes and neutrophils were associated with CSA-AKI incidence. Finally, in the second cohort study, we found that increased pre-operative circulating monocyte counts were associated with increased CSA-AKI incidence.

Circulating monocyte counts in the pre-operative state are associated with increased risk of CSA-AKI development. This finding may be useful in stratifying patients for risk of developing CSA-AKI in routine clinical practice.