Management of Acute Kidney Injury Following Major Abdominal Surgery: A Contemporary Review

LXA4 protected mice from renal ischemia/reperfusion injury by promoting IRG1/Nrf2 and IRAK-M-TRAF6 signal pathways

Excessive inflammatory response and increased oxidative stress play an essential role in the pathophysiology of ischemia/reperfusion (I/R)-induced acute kidney injury (IRI-AKI). Emerging evidence suggests that lipoxin A4 (LXA4), as an endogenous negative regulator in inflammation, can ameliorate several I/R injuries. However, the mechanisms and effects of LXA4 on IRI-AKI remain unknown. In this study, A bilateral renal I/R mouse model was used to evaluate the role of LXA4 in wild-type, IRG1 knockout, and IRAK-M knockout mice. Our results showed that LXA4, as well as 5-LOX and ALXR, were quickly induced, and subsequently decreased by renal I/R. LXA4 pretreatment improved renal I/R-induced renal function impairment and renal damage and inhibited inflammatory responses and oxidative stresses in mice kidneys. Notably, LXA4 inhibited I/R-induced the activation of TLR4 signal pathway including decreased phosphorylation of TAK1, p36, and p65, but did not affect TLR4 and p-IRAK-1. The analysis of transcriptomic sequencing data and immunoblotting suggested that innate immune signal molecules interleukin-1 receptor-associated kinase-M (IRAK-M) and immunoresponsive gene 1 (IRG1) might be the key targets of LXA4. Further, the knockout of IRG1 or IRAK-M abolished the beneficial effects of LXA4 on IRI-AKI. In addition, IRG1 deficiency reversed the up-regulation of IRAK-M by LXA4, while IRAK-M knockout had no impact on the IRG1 expression, indicating that IRAK-M is a downstream molecule of IRG1. Mechanistically, we found that LXA4-promoted IRG1-itaconate not only enhanced Nrf2 activation and increased HO-1 and NQO1, but also upregulated IRAK-M, which interacted with TRAF6 by competing with IRAK-1, resulting in deactivation of TLR4 downstream signal in IRI-AKI. These data suggested that LXA4 protected against IRI-AKI via promoting IRG1/Itaconate-Nrf2 and IRAK-M-TRAF6 signaling pathways, providing the rationale for a novel strategy for preventing and treating IRI-AKI.

Persistent Acute Kidney Injury is Associated with Poor Outcomes and Increased Hospital Cost in Vascular Surgery

BACKGROUND

Postoperative acute kidney injury (AKI) is common after major surgery and is associated with increased morbidity, mortality, and cost. Additionally, there are recent studies demonstrating that time to renal recovery may have a substantial impact on clinical outcomes. We hypothesized that patients with delayed renal recovery after major vascular surgery will have increased complications, mortality, and hospital cost.

METHODS

A single-center retrospective cohort of patients undergoing nonemergent major vascular surgery between 6/1/2014 and 10/1/2020 was analyzed. Development of postoperative AKI (defined using Kidney Disease Improving Global Outcomes (KDIGO) criteria: >50% or > 0.3 mg/dl absolute increase in serum creatinine relative to reference after surgery and before discharge) was evaluated. Patients were divided into 3 groups: no AKI, rapidly reversed AKI (<48 hours), and persistent AKI (≥48 hours). Multivariable generalized linear models were used to evaluate the association between AKI groups and postoperative complications, 90-day mortality, and hospital cost.

RESULTS

A total of 1,881 patients undergoing 1,980 vascular procedures were included. Thirty five percent of patients developed postoperative AKI. Patients with persistent AKI had longer intensive care unit and hospital stays, as well as more mechanical ventilation days. In multivariable logistic regression analysis, persistent AKI was a major predictor of 90-day mortality (odds ratio 4.1, 95% confidence interval 2.4-7.1). Adjusted average cost was higher for patients with any type of AKI. The incremental cost of having any AKI ranged from $3,700 to $9,100, even after adjustment for comorbidities and other postoperative complications. The adjusted average cost for patients stratified by type of AKI was higher among patients with persistent AKI compared to those with no or rapidly reversed AKI.

CONCLUSIONS

Persistent AKI after vascular surgery is associated with increased complications, mortality, and cost. Strategies to prevent and aggressively treat AKI, specifically persistent AKI, in the perioperative setting are imperative to optimize care for this population.

Worsening renal function in hospitalized patients with systolic heart failure: prevalence and risk factors

AIMS

Heart failure (HF) is usually associated with complications of other organs. Renal impairment is seen in a significant proportion of HF patients and is characterized by worsening renal function (WRF). WRF can be used for predicting symptom exacerbation in systolic HF. This study aimed to determine the prevalence and risk factors of WRF among hospitalized patients with systolic HF.

METHODS AND RESULTS

In this cross-sectional study, data from medical records of 347 hospitalized patients diagnosed with HFrEF from 2019 to 2020, admitted to Tabriz Shahid Madani Heart Hospital, who met the predefined inclusion criteria, were retrieved. Patients were divided into two groups based on the in-hospital occurrence of WRF. Laboratory tests and para-clinical findings were collected and analysed using SPSS Version 20.0. Statistical significance was accepted at a P value of <0.05. In this study, 347 hospitalized patients with HFrEF were included. The mean (standard deviation) age was 62.34 (±18.87) years. The mean (SD) length of stay was 6.34 (±4) days. According to our findings, 117 patients (33.71%) had WRF. Following multivariate analysis of potential predictors of WRF occurrence, hyponatremia, haemoglobin concentration, white blood cell count and prior diuretic use were found to be independent predictors for WRF occurrence in patients with systolic heart failure.

CONCLUSIONS

This study revealed that in patients with WRF, mortality rate and length of stay were significantly greater than those of patients without WRF. Initial clinical characteristics of HF patients who developed WRF can help physicians identify patients with a higher risk of WRF.

Early continuous renal replacement therapy for postoperative patient with acute kidney injury following total pancreato-splenectomy: a case report

BACKGROUND

Acute kidney injury is a devastating postoperative complication. Renal replacement therapy is a treatment modality for acute kidney injury. Continuous renal replacement therapy is the treatment of choice for patients with hemodynamic instability. The main question in the management of acute kidney injury is when to initiate the renal replacement therapy. Several studies have demonstrated improvement in patients with septic acute kidney injury, following early continuous renal replacement therapy. To date, no guidelines have been established on the perfect timing to initiate continuous renal replacement therapy. In this case report, we did an early continuous renal replacement therapy as an extracorporeal therapy for blood purification and renal support.

CASE PRESENTATION

Our patient was a 46-year-old male of Malay ethnicity, undergoing total pancreatectomy due to a duodenal tumor. The preoperative assessment showed that the patient was high risk. Intraoperatively, massive surgical bleeding was sustained due to extensive tumor resection; thus, massive blood product transfusion was necessary. After the surgery, the patient suffered from postoperative acute kidney injury. We performed early continuous renal replacement therapy, within 24 hours after the diagnosis of acute kidney injury. Upon completion of continuous renal replacement therapy, the patient's condition improved, and he was discharged from the intensive care unit on the sixth postoperative day.

CONCLUSION

The timing for the initiation of renal replacement therapy remains controversial. It is clear that the "conventional criteria" for initiating renal replacement therapy need correction. We found that early continuous renal replacement therapy initiated in less than 24 hour after the postoperative acute kidney injury diagnosis gave our patient survival benefit.

Major open abdominal surgery is associated with increased levels of endothelial damage and interleukin-6

OBJECTIVE

To examine changes in biomarkers of endothelial glycocalyx shedding, endothelial damage, and surgical stress following major open abdominal surgery and the correlation to postoperative morbidity.

INTRODUCTION

Major abdominal surgery is associated with high levels of postoperative morbidity. Two possible reasons are the surgical stress response and the impairment of the glycocalyx and endothelial cells. Further, the degree of these responses may correlate with postoperative morbidity and complications.

METHODS

A secondary data analysis of prospectively collected data from two cohorts of patients undergoing open liver surgery, gastrectomy, esophagectomy, or Whipple procedure (n = 112). Hemodynamics and blood samples were collected at predefined timestamps and analyzed for biomarkers of glycocalyx shedding (Syndecan-1), endothelial activation (sVEGFR1), endothelial damage (sThrombomodulin (sTM)), and surgical stress (IL6).

RESULTS

Major abdominal surgery led to increased levels of IL6 (0 to 85 pg/mL), Syndecan-1 (17.2 to 46.4 ng/mL), and sVEGFR1 (382.8 to 526.5 pg/mL), peaking at the end of the surgery. In contrast, sTM, did not increase during surgery, but increased significantly following surgery (5.9 to 6.9 ng/mL), peaking at 18 h following the end of surgery. Patients characterized with high postoperative morbidity had higher levels of IL6 (132 vs. 78 pg/mL, p = 0.007) and sVEGFR1 (563.1 vs. 509.4 pg/mL, p = 0.045) at the end of the surgery, and of sTM (8.2 vs. 6.4 ng/mL, p = 0.038) 18 h following surgery.

CONCLUSION

Major abdominal surgery leads to significantly increased levels of biomarkers of endothelial glycocalyx shedding, endothelial damage, and surgical stress, with the highest levels seen in patients developing high postoperative morbidity.

Correlation between perioperative dexmedetomidine administration and postoperative acute kidney injury in hypertensive patients undergoing non-cardiac surgery

Background: Previous studies have suggested that dexmedetomidine may have a protective effect on renal function. However, it is currently unclear whether perioperative dexmedetomidine administration is associated with postoperative acute kidney injury (AKI) incidence risk in hypertensive patients undergoing non-cardiac surgery.

Methods: This investigation was a retrospective cohort study. Hypertensive patients undergoing non-cardiac surgery in Third Xiangya Hospital of Central South University from June 2018 to December 2019 were included. The relevant data were extracted through electronic cases. The univariable analysis identified demographic, preoperative laboratory, and intraoperative factors associated with acute kidney injury. Multivariable stepwise logistic regression was used to assess the association between perioperative dexmedetomidine administration and postoperative acute kidney injury after adjusting for interference factors. In addition, we further performed sensitivity analyses in four subgroups to further validate the robustness of the results.

Results: A total of 5769 patients were included in this study, with a 7.66% incidence of postoperative acute kidney injury. The incidence of postoperative acute kidney injury was lower in the dexmedetomidine-administered group than in the control group (4.12% vs. 8.06%, p &lt; 0.001). In the multivariable stepwise logistic regression analysis, perioperative dexmedetomidine administration significantly reduced the risk of postoperative acute kidney injury after adjusting for interference factors [odds ratio (OR) = 0.56, 95% confidence interval (CI): 0.36–0.87, p = 0.010]. In addition, sensitivity analysis in four subgroups indicated parallel findings: i) eGRF &lt;90 mL/min·1.73/m2 subgroup (OR = 0.40, 95% CI: 0.19–0.84, p = 0.016), ii) intraoperative blood loss &lt;1000 mL subgroup (OR = 0.58, 95% CI: 0.36–0.94, p = 0.025), iii) non-diabetes subgroup (OR = 0.51, 95% CI: 0.29–0.89, p = 0.018), and iv) older subgroup (OR = 0.55, 95% CI: 0.32–0.93, p = 0.027).

Conclusion: In conclusion, our study suggests that perioperative dexmedetomidine administration is associated with lower risk and less severity of postoperative acute kidney injury in hypertensive individuals undergoing non-cardiac surgery. Therefore, future large-scale RCT studies are necessary to validate this benefit.

Intraoperative Hypertension Is Associated with Postoperative Acute Kidney Injury after Laparoscopic Surgery

Background: It is well demonstrated that intraoperative blood pressure is associated with postoperative acute kidney injury (AKI); however, the association between severity and duration of abnormal intraoperative blood pressure (BP) with AKI in patients undergoing laparoscopic surgery remains unknown. Methods: This retrospective cohort study included 12,414 patients aged ≥ 18 years who underwent a single elective laparoscopic abdominal surgery during hospitalization between October 2011 and April 2017. Multivariate stepwise logistic regressions were applied to determine the correlation between the severity and duration of intraoperative mean arterial pressure (MAP, (systolic BP + 2 × diastolic BP)/3), acute intraoperative hypertension (IOTH) and postoperative AKI, in different periods of surgery. Results: A total of 482 hospitalized patients (3.9%) developed surgery-related AKI. Compared with those without IOTH or with preoperative mean MAP (80–85 mmHg), acute elevated IOTH (odds ratio, OR, 1.4, 95% CI, 1.1 to 1.7), mean MAP 95–100 mmHg (OR, 1.8; 95% CI, 1.3 to 2.7), MAP 100–105 mmHg (OR, 2.4; 95% CI, 1.6 to 3.8), and more than 105 mmHg (OR, 1.9; 95% CI, 1.1 to 3.3) were independent of other risk factors in a diverse cohort undergoing laparoscopic surgery. In addition, the risk of postoperative AKI appeared to result from long exposure (≥20 min) to IOTH (OR, 1.9; 95% CI, 1.5 to 2.5) and MAP ≥ 115 mmHg (OR, 2.2; 95% CI, 1.6 to 3.0). Intraoperative hypotension was not found to be associated with AKI in laparoscopic surgery patients. Conclusions: Postoperative AKI correlates positively with intraoperative hypertension in patients undergoing laparoscopic surgery. These findings provide an intraoperative evaluation criterion to predict the occurrence of postoperative AKI.

Postoperative Acute Kidney Injury

Postoperative AKI is a common complication of major surgery and is associated with significant morbidity and mortality. The Kidney Disease Improving Global Outcomes AKI definition allows consensus classification and identification of postoperative AKI through changes in serum creatinine and/or urine output. However, such conventional diagnostic criteria may be inaccurate in the postoperative period, suggesting a potential to refine diagnosis by application of novel diagnostic biomarkers. Risk factors for the development of postoperative AKI can be thought of in terms of preoperative, intraoperative, and postoperative factors and, as such, represent areas that may be targeted perioperatively to minimize the risk of AKI. The treatment of postoperative AKI remains predominantly supportive, although application of management bundles may translate into improved outcomes.

Kidney Damage and Stress Biomarkers for Early Identification of Drug-Induced Kidney Injury: A Systematic Review

INTRODUCTION

Acute kidney injury (AKI) resulting from nephrotoxic medication use is prominent in hospitalized patients and is attributable to overall increases in mortality and costs of care. Serum creatinine (SCr), the current standard for identifying drug-induced AKI (DIAKI) is often delayed in its response to kidney insult by 26-36 h.

OBJECTIVE

This systematic review seeks to evaluate the clinical utility of several novel kidney damage and stress biomarkers for the prediction/timely detection of DIAKI, in comparison with traditional methods.

METHODS

A systematic review of the CINAHL, Cochrane Library, Embase, and PubMed databases was conducted per the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) 2020 guidelines, for articles analyzing the use of β2-microglobulin (B2M), interleukin (IL)-18, kidney injury molecule-1 (KIM-1), liver-type fatty acid-binding protein (L-FABP), neutrophil gelatinase-associated lipocalin (NGAL), and tissue inhibitor of metalloproteinase-2 * insulin-like growth factor-binding protein 7 [TIMP-1]*[IGFBP-7], for identifying DIAKI. Primary outcomes included time to DIAKI diagnosis using traditional methods and the time to significant difference in biomarker concentrations between DIAKI and non-AKI study subjects. Secondary outcomes included biomarker concentrations at the time of significant difference between the AKI status groups.

RESULTS

Fifteen unique articles were identified from the literature search. Twelve studies consisted of strictly hospitalized patient populations and three studies included hospitalized patients and patients discharged to home treatment. No studies reported values for urine volume output. Seventy-three percent of studies reported earlier times to significant difference of novel biomarker concentrations between the AKI and non-AKI groups than diagnosis of DIAKI by SCr alone. Significant variation was observed for individual urine biomarker concentrations at time of significant difference between the AKI status groups.

CONCLUSIONS

All analyzed biomarkers showed potential for use as early clinical markers of DIAKI, however further consensus on threshold urine concentrations for DIAKI is needed for meaningful implementation of these biomarkers in clinical practice.

A Micellar Formulation of Quercetin Prevents Cisplatin Nephrotoxicity

The antioxidant flavonoid quercetin has been shown to prevent nephrotoxicity in animal models and in a clinical study and is thus a very promising prophylactic candidate under development. Quercetin solubility is very low, which handicaps clinical application. The aim of this work was to study, in rats, the bioavailability and nephroprotective efficacy of a micellar formulation of Pluronic F127-encapsulated quercetin (P-quercetin), with improved hydrosolubility. Intraperitoneal administration of P-quercetin leads to an increased plasma concentration and bioavailability of quercetin compared to the equimolar administration of natural quercetin. Moreover, P-quercetin retains overall nephroprotective properties, and even slightly improves some renal function parameters, when compared to natural quercetin. Specifically, P-quercetin reduced the increment in plasma creatinine (from 3.4 ± 0.5 to 1.2 ± 0.3 mg/dL) and urea (from 490.9 ± 43.8 to 184.1 ± 50.1 mg/dL) and the decrease in creatinine clearance (from 0.08 ± 0.02 to 0.58 ± 0.19 mL/min) induced by the nephrotoxic chemotherapeutic drug cisplatin, and it ameliorated histological evidence of tubular damage. This new formulation with enhanced kinetic and biopharmaceutical properties will allow for further exploration of quercetin as a candidate nephroprotector at lower dosages and by administration routes oriented towards its clinical use.