Analysis of Risk Factors for Perioperative Acute Kidney Injury and Management Strategies

Machine learning approach to predict acute kidney injury among patients undergoing multi-level spinal posterior instrumented fusion

Background

Acute kidney injury (AKI) after spinal fusion is a significant morbidity that can lead to poor post-surgical outcomes. Identifying AKI risk factors and developing a risk model can raise surgeons' awareness and allow them to take actions to mitigate the risks. The objective of the current study is to develop machine learning (ML) models to assess patient risk factors predisposing to AKI after posterior spinal instrumented fusion.

Methods

Data was collected from the IBM MarketScan Database (2009-2021) for patients >18 years old who underwent spinal fusion with posterior instrumentation (3-6 levels). AKI incidence (defined by the International Classification of Diseases codes) was recorded 90-day post-surgery. Risk factors for AKI were investigated and compared through several ML models including logistic regression, linear support vector machine (LSVM), random forest, extreme gradient boosting (XGBoost), and neural networks.

Results

Among the 141,697 patients who underwent fusion with posterior instrumentation (3-6 levels), the overall rate of 90-day AKI was 2.96%. We discovered that the logistic regression model and LSVM demonstrated the best predictions with area under the curve (AUC) values of 0.75. The most important AKI prediction features included chronic renal disease, hypertension, diabetes mellitus ± complications, older age (>50 years old), and congestive heart failure. Patients who did not have these five key risk factors had a 90-day AKI rate of 0.29%. Patients who had an increasing number of key risk factors subsequently had higher risks of postoperative AKI.

Conclusions

The analysis of the data with different ML models identified 5 key variables that are most closely associated with AKI: chronic renal disease, hypertension, diabetes mellitus ± complications, older age (>50 years old), and congestive heart failure. These variables constitute a simple risk calculator with additive odds ratio ranging from 3.38 (1 risk factor) to 91.10 (5 risk factors) over 90 days after posterior spinal fusion surgery. These findings can help surgeons risk-stratify their patients for AKI risk, and potentially guide post-operative monitoring and medical management.

Perioperative acute kidney injury: The renoprotective effect and mechanism of dexmedetomidine

Dexmedetomidine (DEX) is a highly selective and potent α2-adrenoceptor (α2-AR) agonist that is widely used as a clinical anesthetic to induce anxiolytic, sedative, and analgesic effects. In recent years, a growing body of evidence has demonstrated that DEX protects against acute kidney injury (AKI) caused by sepsis, drugs, surgery, and ischemia-reperfusion (I/R) in organs or tissues, indicating its potential role in the prevention and treatment of AKI. In this review, we summarized the evidence of the renoprotective effects of DEX on different models of AKI and explored the mechanism. We found that the renoprotective effects of DEX mainly involved antisympathetic effects, reducing inflammatory reactions and oxidative stress, reducing apoptosis, increasing autophagy, reducing ferroptosis, protecting renal tubular epithelial cells (RTECs), and inhibiting renal fibrosis. Thus, the use of DEX is a promising strategy for the management and treatment of perioperative AKI. The aim of this review is to further clarify the renoprotective mechanism of DEX to provide a theoretical basis for its use in basic research in various AKI models, clinical management, and the treatment of perioperative AKI.

Effects of Subcostal Anterior Quadratus Lumborum Block with and without Dexmedetomidine on Postoperative Rehabilitation in Patients Undergoing Laparoscopic Renal Surgery: A Prospective Double-Blinded Randomized Controlled Study

Background

The combination of different anesthesia techniques or adjuvant drugs can relieve the stress response to surgery, reduce adverse reactions and improve the clinical outcome. We investigated the effects of subcostal anterior quadratus lumborum block (SQLB) with and without dexmedetomidine (DEX) on postoperative rehabilitation for laparoscopic renal surgery (LRS).

Methods

We included 90 patients in this single-center study. All were scheduled for elective laparoscopic radical or partial nephrectomy under general anesthesia (GA). We randomly and evenly assigned them to three groups: Group GA (GA alone), Group QG (SQLB with 30 mL of 0.25% ropivacaine and GA), and Group DQG (SQLB with 30 mL of 0.25% ropivacaine plus 1 μg/kg DEX and GA). The primary outcomes were serum creatinine (Cr) and blood urea nitrogen (BUN) levels; the secondary outcomes included the average numeric rating scale (NRS) scores at rest and during activity within 48 h postoperatively; perioperative opioid consumption; the time to first ambulation, exhaust, and fluid intake, and postoperative adverse reactions.

Results

The serum Cr and BUN levels in Group DQG decreased significantly compared with Group GA (P < 0.05). The average NRS scores in Group DQG were significantly lower than other two groups (P < 0.05). Furthermore, the indexes reduced significantly in Group QG compared with Group GA (P < 0.05). Groups DQG and QG had lower consumption of opioid compared with Group GA (P < 0.05). The recovery indicators in Groups DQG and QG were higher quality than Group GA (P < 0.05). The incidences of adverse reactions in Group DQG was significantly lower than the other groups (P < 0.05).

Conclusion

SQLB with and without DEX could attenuate postoperative pain, reduce opioids requirement and side effects, as well as facilitate postoperative early rehabilitation. More interesting, SQLB with DEX could confer kidney protection.

Clinical Trial Registration Number

The Chinese Clinical Trial Registry (ChiCTR2200061554).

Future Directions in Optimizing Anesthesia to Reduce Perioperative Acute Kidney Injury

BACKGROUND

Perioperative acute kidney injury (AKI) is common in surgical patients and is associated with high morbidity and mortality. There are currently few options for AKI prevention and treatment. Due to its complex pathophysiology, there is no efficient medication therapy to stop the onset of the injury or repair the damage already done. Certain anesthetics, however, have been demonstrated to affect the risk of perioperative AKI in some studies. The impact of anesthetics on renal function is particularly important as it is closely related to the prognosis of patients. Some anesthetics can induce anti-inflammatory, anti-necrotic, and anti-apoptotic effects. Propofol, sevoflurane, and dexmedetomidine are a few examples of anesthetics that have protective association with AKI in the perioperative period.

SUMMARY

In this study, we reviewed the clinical characteristics, risk factors, and pathogenesis of AKI. Subsequently, the protective effects of various anesthetic agents against perioperative AKI and the latest research are introduced.

KEY MESSAGE

This work demonstrates that a thorough understanding of the reciprocal effects of anesthetic drugs and AKI is crucial for safe perioperative care and prognosis of patients. However, more complete mechanisms and pathophysiological processes still need to be further studied.

Tilianin Reduces Apoptosis via the ERK/EGR1/BCL2L1 Pathway in Ischemia/Reperfusion-Induced Acute Kidney Injury Mice

Background: Acute kidney injury (AKI) is a common syndrome impacting about 13.3 million patients per year. Tilianin has been reported to alleviate myocardial ischemia/reperfusion (I/R) injury, while its effect on AKI is unknown; thus, this study aimed to explore if tilianin protects I/R-induced AKI and the underlying mechanisms.

Methods: The microarray dataset GSE52004 was downloaded from GEO DataSets (Gene Expression Omnibus). Differential expression analysis and gene-set enrichment analysis (GSEA) were performed by R software to identify apoptosis pathway-related genes. Then, RcisTarget was applied to identify the transcription factor (TF) related to apoptosis. The STRING database was used to construct a protein–protein interaction (PPI) network. Cytoscape software visualized PPI networks, and hub TFs were selected via cytoHubba. AutoDock was used for molecular docking of tilianin and hub gene-encoded proteins. The expression levels of hub genes were assayed and visualized by quantitative real-time PCR, Western blotting, and immunohistochemistry by establishing I/R-induced AKI mouse models.

Results: Bioinformatics analysis showed that 34 genes, including FOS, ATF4, and Gadd45g, were involved in the apoptosis pathway. In total, seven hub TFs might play important roles in tilianin-regulating apoptosis pathways. In in vivo, tilianin improved kidney function and reduced the number of TUNEL-positive renal tubular epithelial cells (RTECs) after I/R-induced AKI. Tilianin reduced the activation of the ERK pathway and then downregulated the expression of EGR1. This further ameliorated the expression of anti-apoptotic genes such as BCL2L1 and BCL2, reduced pro-apoptotic genes such as BAD, BAX, and caspase-3, and reduced the release of cytochrome c.

Conclusion: Tilianin reduced apoptosis after I/R-induced AKI by the ERK/EGR1/BCL2L1 pathway. Our findings provided novel insights for the first time into the protective effect and underlying molecular mechanisms of tilianin on I/R-induced AKI.

Scutellarin protects the kidney from ischemia/reperfusion injury by targeting Nrf2

BACKGROUND

Acute kidney injury (AKI) results in high morbidity and mortality among inpatients, while effective treatment and intervention are still absent. Therefore, this study aims to explore the effects of Scutellarin (Scu) in experimental models in vivo and in vitro.

METHODS

In vivo experiment, we employed a total of 30 Wistar rats, which further were modelled by a bilateral renal pedicle clip for 45 min, then received 50 mg/kg/day Scu. In vitro, HK-2 cells were administered with 20μΜ Scu and then incubated in hypoxia/reoxygenation (H/R) conditions for 24 h. The knockdown of Nrf2 expression was conducted by small interfering RNA (siRNA) transfection.

RESULTS

As a result, the AKI model was well established with an increased SCr, BUN, KIM-1 level, and histological injury score, while Scu treatment reduced the levels above and increased the antioxidative enzyme HO-1. H/R induced an increase of ROS in HK-2 cells, while Scu decreased the ROS level. Bioinformatics results showed the transcription factor Nrf2 was a hub protein during the AKI, which also bound to Scu with low binding energy, indicating that the downstream effect of Scu might be mediated by Nrf2. To verify the suppose above, we employed siRNA against Nrf2, which shows a significant increase in ROS after Nrf2 was blocked. Meanwhile, the HO-1 showed similar expression compared with the 'H/R + Nrf2 siRNA' and 'H/R + Nrf2 siRNA + Scu' group, implying the protective effect of Scu was mediated by the Nrf2/HO-1 pathway.

CONCLUSION

Scu led to up-regulation of HO-1 through activating the Nrf2 signalling pathway, protecting the kidneys from ischemia/reperfusion (I/R)-induced oxidative damage.