Incidence and associations of acute kidney injury after major abdominal surgery

Association between preoperative proton pump inhibitor use and postoperative acute kidney injury in patients undergoing major surgery

BACKGROUND

Acute kidney injury (AKI) is a severe postoperative complication in patients undergoing major surgery. Proton pump inhibitors (PPIs) are used preoperatively as prophylaxis for postoperative gastrointestinal bleeding. Whether preoperative PPI use is associated with an increased risk of postoperative AKI remains uncertain.

METHODS

This retrospective cohort study used electronic medical records from the clinical data warehouse of Peking University First Hospital to screen all adult hospitalizations undergoing major surgery between 1 January 2018 and 31 December 2020. Exposure was preoperative PPI use, defined as PPI use within 7 days before major surgery. The primary outcome was postoperative AKI, defined as AKI occurring within 7 days after major surgery; secondary outcomes included in-hospital AKI and in-hospital mortality.

RESULTS

A total of 21,533 patients were included in the study (mean [SD] age, 57.8 [15.0] years; 51.2% male), of which 944 (4.4%) were prescribed PPI within 7 days before major surgery (PPI users). Overall, 72 PPI users (7.6%) and 356 non-users (1.7%) developed postoperative AKI. After adjustment, preoperative PPI use was associated with an increased risk of postoperative AKI (adjusted OR, 1.47; 95% CI, 1.04-2.07) and in-hospital AKI (adjusted OR, 1.41; 95% CI, 1.03-1.94). Moreover, subgroup analyses showed that the risk of PPI on postoperative AKI was amplified by the concomitant use of non-steroidal anti-inflammatory drugs or diuretics. No significant difference was observed between preoperative PPI use and in-hospital mortality in the fully adjusted model (adjusted OR 1.63; 95% CI, 0.55-4.85).

CONCLUSIONS

Preoperative PPI use was associated with an increased risk of AKI in patients undergoing major surgery. This risk may be enhanced by the concomitant use of other nephrotoxic drugs. Clinicians should weigh the pros and cons before initiating PPI prophylaxis.

Risk factors for postoperative acute kidney injury after radical cystectomy for bladder cancer in the era of ERAS protocols: A retrospective observational study

BACKGROUND

Radical cystectomy (RC) is a major surgery associated with a high morbidity rate. Perioperative fluid management according to enhanced recovery after surgery (ERAS) protocols aims to maintain patients in an optimal euvolemic state while exposing them to acute kidney injury (AKI) in the event of hypovolemia. Postoperative AKI is associated with severe morbidity and mortality. Our main objective was to determine the association between perioperative variables, including some component of ERAS protocols, and occurrence of postoperative AKI within the first 30 days following RC in patients presenting bladder cancer. Our secondary objective was to evaluate the association between a postoperative AKI and the occurrence or worsening of a chronic kidney disease (CKD) within the 2 years following RC.

METHODS

We conducted a retrospective observational study in a referral cancer center in France on 122 patients who underwent an elective RC for bladder cancer from 01/02/2015 to 30/09/2019. The primary endpoint was occurrence of AKI between surgery and day 30. The secondary endpoint was survival without occurrence or worsening of a postoperative CKD. AKI and CKD were defined by KDIGO (Kidney Disease: Improving Global Outcomes) classification. Logistic regression analyse was used to determine independent factors associated with postoperative AKI. Fine and Gray model was used to determine independent factors associated with postoperative CKD.

RESULTS

The incidence of postoperative AKI was 58,2% (n = 71). Multivariate analysis showed 5 factors independently associated with postoperative AKI: intraoperative restrictive vascular filling < 5ml/kg/h (OR = 4.39, 95%CI (1.05-18.39), p = 0.043), postoperative sepsis (OR = 4.61, 95%CI (1.05-20.28), p = 0.043), female sex (OR = 0.11, 95%CI (0.02-0.73), p = 0.022), score SOFA (Sequential Organ Failure Assessment) at day 1 (OR = 2.19, 95%CI (1.15-4.19), p = 0.018) and delta serum creatinine D1 (OR = 1.06, 95%CI (1.02-1.11), p = 0.006). During the entire follow-up, occurrence or worsening of CKD was diagnosed in 36 (29.5%). A postoperative, AKI was strongly associated with occurrence or worsening of a CKD within the 2 years following RC even after adjustment for confounding factors (sHR = 2.247, 95%CI [1.051-4.806, p = 0.037]).

CONCLUSION

A restrictive intraoperative vascular filling < 5ml/kg/h was strongly and independently associated with the occurrence of postoperative AKI after RC in cancer bladder patients. In this context, postoperative AKI was strongly associated with the occurrence or worsening of CKD within the 2 years following RC. A personalized perioperative fluid management strategy needs to be evaluated in these high-risk patients.

Association of velocity-pressure loop-derived values recorded during neurosurgical procedures with postoperative organ failure biomarkers: a retrospective single-center study

BACKGROUND

Perioperative renal and myocardial protection primarily depends on preoperative prediction tools, along with intraoperative optimization of cardiac output (CO) and mean arterial pressure (MAP). We hypothesise that monitoring the intraoperative global afterload angle (GALA), a proxy of ventricular afterload derived from the velocity pressure (VP) loop, could better predict changes in postoperative biomarkers than the recommended traditional MAP and CO.

METHOD

This retrospective monocentric study included patients programmed for neurosurgery with continuous VP loop monitoring. Patients with hemodynamic instability were excluded. Those presenting a 1-day post-surgery increase in creatinine, B-type natriuretic peptide, or troponin Ic us were labelled Bio+, Bio- otherwise. Demographics, intra-operative data, and comorbidities were considered as covariates. The study aimed to determine if intraoperative GALA monitoring could predict early postoperative biomarker disruption.

RESULT

From November 2018 to November 2020, 86 patients were analysed (Bio+/Bio- = 47/39). Bio+ patients were significantly older (62 [54-69] vs. 42 [34-57] years, p <  0.0001), More often hypertensive (25% vs. 9%, p = 0.009), and more frequently treated with antihypertensive drugs (31.9% vs. 7.7%, p = 0.013). GALA was significantly larger in Bio+ patients (40 [31-56] vs. 23 [19-29] °, p < 0.0001), while CO, MAP, and cumulative time spent <65mmHg were similar between groups. GALA exhibited strong predictive performances for postoperative biological deterioration (AUC = 0.88 [0.80-0.95]), significantly outperforming MAP (MAP AUC = 0.55 [0.43-0.68], p < 0.0001).

CONCLUSION

GALA under general anaesthesia prove more effective in detecting patients at risk of early cardiac or renal biological deterioration, compared to classical hemodynamic parameters.

Association between intraoperative tidal volume and postoperative acute kidney injury in non-cardiac surgical patients using a propensity score-weighted analysis

Acute kidney injury (AKI) is related to adverse clinical outcomes. Therefore, identifying patients at increased risk of postoperative AKI and proactively providing appropriate care is crucial. However, only a limited number of modifiable risk factors have been recognized to mitigate AKI risk. We retrospectively analyzed adult patients who underwent endotracheal intubation and mechanical ventilation of more than 2 h during non-cardiac surgery at Seoul National University Hospital from January 2011 to November 2022. Patients were grouped into low- or high-tidal volume groups based on their intraoperative tidal volume relative to their predicted body weight (PBW) of 8 ml/kg. The association between intraoperative tidal volume and postoperative AKI was evaluated using inverse probability of treatment weighting (IPTW), adjusting for various preoperative confounders. Among the 37,726 patients included, the incidence of postoperative AKI was 4.1%. The odds of postoperative AKI risk were significantly higher in the high-tidal volume group than in the low-tidal volume group before and after IPTW (odds ratio [OR] 1.20, 95% confidence interval [CI] 1.08-1.32, P = 0.001 and OR: 1.10, 95% CI 1.02-1.19, P = 0.010, respectively). In the multivariable logistic regression analysis after IPTW, a high tidal volume was independently associated with an increased risk of postoperative AKI (OR: 1.21, 95% CI 1.12-1.30, P < 0.001). In this propensity score-weighted analysis, an intraoperative high tidal volume of more than 8 ml/kg PBW was significantly associated with an increased risk of postoperative AKI after IPTW in non-cardiac surgical patients. Intraoperative tidal volume showed potential as a modifiable risk factor for preventing postoperative AKI.

Association between muscular tissue desaturation and acute kidney injury in older patients undergoing major abdominal surgery: a prospective cohort study

PURPOSE

Present study was designed to investigate the association between muscular tissue desaturation and acute kidney injury (AKI) in older patients undergoing major abdominal surgery.

METHOD

A total of 253 patients (≥ 65 years old) who underwent abdominal surgery with expected duration ≥ 2 h were enrolled. Muscular tissue oxygen saturation (SmtO2) was monitored at quadriceps and bilateral flanks during surgery. Muscular desaturation was defined as SmtO2 < 90% baseline lasting for > 60 s. The primary outcome was the incidence of AKI within postoperative 7 days. The association between muscular desaturation and AKI was analyzed by multivariable logistic regression model. The secondary outcomes indicated the other complications within postoperative 30 days.

RESULTS

Among 236 patients, 44 (18.6%) of them developed AKI. The incidence of muscular desaturation at quadriceps was 28.8% (68/236). Patients with muscular desaturation had higher incidence of AKI than those without desaturation (27.9% [19/68], vs. 14.9% [25/168], P = 0.020). After adjustment of confounders, multivariable analysis showed that muscular desaturation at quadriceps was significantly associated with an increased risk of AKI (OR = 2.84, 95% CI 1.21-6.67, P = 0.016). Muscular desaturations at left and right flank were also associated with an increased risk of AKI (OR = 6.38, 95% CI 1.78-22.89, P = 0.004; OR = 8.90, 95% CI 1.42-45.63; P = 0.019, respectively). Furthermore, patients with muscular desaturation may have a higher risk of pulmonary complications, sepsis and stroke at 30-day follow-up.

CONCLUSION

Muscular desaturation was associated with postoperative AKI in older patients undergoing major abdominal surgery which may serve as a predictor of AKI.

Impact of spinal or epidural anaesthesia on perioperative outcomes in adult noncardiac surgery: a narrative review of recent evidence

Spinal and epidural anaesthesia and analgesia are important anaesthetic techniques, familiar to all anaesthetists and applied to patients undergoing a range of surgical procedures. Although the immediate effects of a well-conducted neuraxial technique on nociceptive and sympathetic pathways are readily observable in clinical practice, the impact of such techniques on patient-centred perioperative outcomes remains an area of uncertainty and active research. The aim of this review is to present a narrative synthesis of contemporary clinical science on this topic from the most recent 5-year period and summarise the foundational scholarship upon which this research was based. We searched electronic databases for primary research, secondary research, opinion pieces, and guidelines reporting the relationship between neuraxial procedures and standardised perioperative outcomes over the period 2018-2023. Returned citation lists were examined seeking additional studies to contextualise our narrative synthesis of results. Articles were retrieved encompassing the following outcome domains: patient comfort, renal, sepsis and infection, postoperative cancer, cardiovascular, and pulmonary and mortality outcomes. Convincing evidence of the beneficial effect of epidural analgesia on patient comfort after major open thoracoabdominal surgery outcomes was identified. Recent evidence of benefit in the prevention of pulmonary complications and mortality was identified. Despite mechanistic plausibility and supportive observational evidence, there is less certain experimental evidence to support a role for neuraxial techniques impacting on other outcome domains. Evidence of positive impact of neuraxial techniques is best established for the domains of patient comfort, pulmonary complications, and mortality, particularly in the setting of major open thoracoabdominal surgery. Recent evidence does not strongly support a significant impact of neuraxial techniques on cancer, renal, infection, or cardiovascular outcomes after noncardiac surgery in most patient groups.

Aurantiamide mitigates acute kidney injury by suppressing renal necroptosis and inflammation via GRPR-dependent mechanism

Acute kidney injury (AKI) manifests as a clinical syndrome characterised by the rapid accumulation of metabolic wastes, such as blood creatinine and urea nitrogen, leading to a sudden decline in renal function. Currently, there is a lack of specific therapeutic drugs for AKI. Previously, we identified gastrin-releasing peptide receptor (GRPR) as a pathogenic factor in AKI. In this study, we investigated the therapeutic potential of a novel Chinese medicine monomer, aurantiamide (AA), which exhibits structural similarities to our previously reported GRPR antagonist, RH-1402. We compared the therapeutic efficacy of AA with RH-1402 both in vitro and in vivo using various AKI models. Our results demonstrated that, in vitro, AA attenuated injury, necroptosis, and inflammatory responses in human renal tubular epithelial cells subjected to repeated hypoxia/reoxygenation and lipopolysaccharide stimulation. In vivo, AA ameliorated renal tubular injury and inflammation in mouse models of ischemia/reperfusion and cecum ligation puncture-induced AKI, surpassing the efficacy of RH-1402. Furthermore, molecular docking and cellular thermal shift assay confirmed GRPR as a direct target of AA, which was further validated in primary cells. Notably, in GRPR-silenced HK-2 cells and GRPR systemic knockout mice, AA failed to mitigate renal inflammation and injury, underscoring the importance of GRPR in AA's mechanism of action. In conclusion, our study has demonstrated that AA serve as a novel antagonist of GRPR and a promising clinical candidate for AKI treatment.

Biomarker-guided acute kidney injury risk assessment under liberal versus restrictive fluid therapy - the prospective-randomized MAYDAY-trial

Acute kidney injury (AKI) prevalence in surgical patients is high, emphasizing the need for preventative measures. This study addresses the insufficient evidence on nephroprotective intraoperative fluid resuscitation and highlights the drawbacks of relying solely on serum creatinine/urine output to monitor kidney function. This study assessed the impact of intraoperative fluid management on AKI in female breast cancer patients undergoing autologous breast reconstruction, utilizing novel urinary biomarkers (TIMP-2 and IGFBP-7). In a monocentric prospective randomized controlled trial involving 40 patients, liberal (LFA) and restrictive (FRV) fluid management strategies were compared. TIMP-2 and IGFBP-7 biomarker levels were assessed using the NephroCheck (bioMerieux, France) test kit at preoperative, immediate postoperative, and 24-h postoperative stages. FRV showed significantly higher immediate postoperative biomarker levels, indicating renal tubular stress. FRV patients had 21% (4/19) experiencing AKI compared to 13% (2/15) in the LFA group according to KDIGO criteria (p = 0.385). Restrictive fluid resuscitation increases the risk of AKI in surgical patients significantly, emphasizing the necessity for individualized hemodynamic management. The findings underscore the importance of urinary biomarkers in early AKI detection.

The effect of human albumin administration on postoperative renal function following major surgery: a systematic review and meta-analysis

Optimal fluid management during major surgery is of considerable concern to anesthesiologists. Although crystalloids are the first choice for fluid management, the administration of large volumes of crystalloids is associated with poor postoperative outcomes. Albumin can be used for fluid management and may protect renal function. However, data regarding the effects of albumin administration on kidney function are conflicting. As such, the present study aimed to investigate the effect of albumin administration on renal function in patients undergoing major surgery and compare its effects with those of crystalloid fluid. The Embase, Medline, Web of Science, Cochrane Library, and KoreaMed databases were searched for relevant studies. The primary endpoint of the meta-analysis was the incidence of postoperative kidney injury, including acute kidney injury and renal replacement therapy. Twelve studies comprising 2311 patients were included; the primary endpoint was analyzed in four studies comprising 1749 patients. Perioperative albumin levels in patients undergoing major surgery did not significantly influence kidney dysfunction (p = 0.98). Postoperative fluid balance was less positive in patients who underwent major surgery and received albumin than in those who received crystalloids. Owing to the limitations of this meta-analysis, it remains unclear whether albumin administration during major surgery is better than crystalloid fluid for improving postoperative renal function.

The impact of intraoperative hypotension on postoperative acute kidney injury, mortality and length of stay following off-pump coronary artery bypass grafting surgery: a single-center retrospective cohort study

BACKGROUND

Off-pump coronary artery bypass grafting (OPCABG) presents distinct hemodynamic characteristics, yet the relationship between intraoperative hypotension and short-term adverse outcomes remains clear. Our study aims to investigate association between intraoperative hypotension and postoperative acute kidney injury (AKI), mortality and length of stay in OPCABG patients.

METHODS

Retrospective data of 494 patients underwent OPCABG from January 2016 to July 2023 were collected. We analyzed the relationship between intraoperative various hypotension absolute values (MAP > 75, 65 < MAP ≤ 75, 55 < MAP ≤ 65, MAP ≤ 55 mmHg) and postoperative AKI, mortality and length of stay. Logistic regression assessed the impacts of exposure variable on AKI and postoperative mortality. Linear regression was used to analyze risk factors on the length of intensive care unit stay (ICU) and hospital stay.

RESULTS

The incidence of AKI was 31.8%, with in-hospital and 30-day mortality at 2.8% and 3.5%, respectively. Maintaining a MAP greater than or equal 65 mmHg [odds ratio (OR) 0.408; p = 0.008] and 75 mmHg (OR 0.479; p = 0.024) was significantly associated with a decrease risk of AKI compared to MAP less than 55 mmHg for at least 10 min. Prolonged hospital stays were linked to low MAP, while in-hospital mortality and 30-day mortality were not linked to IOH but exhibited correlation with a history of myocardial infarction. AKI showed correlation with length of ICU stay.

CONCLUSIONS

MAP > 65 mmHg emerges as a significant independent protective factor for AKI in OPCABG and IOH is related to length of hospital stay. Proactive intervention targeting intraoperative hypotension may provide a potential opportunity to reduce postoperative renal injury and hospital stay.

TRIAL REGISTRATION

ChiCTR2400082518. Registered 31 March 2024. https://www.chictr.org.cn/bin/project/edit?pid=225349 .

An explainable machine learning model to predict early and late acute kidney injury after major hepatectomy

BACKGROUND

Risk assessment models for acute kidney injury (AKI) after major hepatectomy that differentiate between early and late AKI are lacking. This retrospective study aimed to create a model predicting AKI through machine learning and identify features that contribute to the development of early and late AKI.

METHODS

Patients that underwent major hepatectomy were categorized into the No-AKI, Early-AKI (within 48 h) or Late-AKI group (between 48 h and 7 days). Modeling was done with 20 perioperative features and the performance of prediction models were measured by the area under the receiver operating characteristic curve (AUROCC). Shapley Additive Explanation (SHAP) values were utilized to explain the outcome of the prediction model.

RESULTS

Of the 1383 patients included in this study, 1229, 110 and 44 patients were categorized into the No-AKI, Early-AKI and Late-AKI group, respectively. The CatBoost classifier exhibited the greatest AUROCC of 0.758 (95% CI: 0.671-0.847) and was found to differentiate well between Early and Late-AKI. We identified different perioperative features for predicting each outcome and found 1-year mortality to be greater for Early-AKI.

CONCLUSIONS

Our results suggest that risk factors are different for Early and Late-AKI after major hepatectomy, and 1-year mortality is greater for Early-AKI.

Statistical analysis plan for the biomarker-guided intervention to prevent acute kidney injury after major surgery (BigpAK-2) study: An international randomised controlled multicentre trial

Objective

This article describes the statistical analysis plan for the Biomarker-guided intervention to prevent AKI after major surgery (BigpAK-2) trial.

Design

Adaptive trial design with an interim analysis after enrolment of 618 evaluable patients.

Setting

The BigpAK.-2 trial is an international, prospective, randomised controlled multicentre study.

Participants

The BigpAK-2 study enrols patients after major surgery who are admitted to the intensive care or high dependency unit and are at high-risk for postoperative AKI as identified by urinary biomarkers (tissue inhibitor of metalloproteinases-2 and insulin-like growth factor binding protein 7 ([TIMP-2]∗[IGFBP7]) will be enrolled.

Intervention

Patients are randomly and evenly allocated to standard of care (control) group or the implementation of a nephroprotective care bundle (intervention group), as recommended by the Kidney Disease: Improving Global Outcomes (KDIGO) guidelines. The KDIGO care bundle recommends discontinuation of nephrotoxic agents if possible, ensuring adequate volume status and perfusion pressure, considering functional haemodynamic monitoring, regular monitoring of serum creatinine and urine output, avoiding hyperglycemia, and considering alternatives to radiocontrast procedures when possible.

Results

The BigpAK-2 study investigates whether the biomarker-gudied implementation of the KDIGO care bundle reduces the incidence of moderate or severe AKI (stage 2 or 3), according to the KDIGO 2012 criteria, within 72 h after surgery.

Conclusion

AKI is a common and often severe complication after major surgery. As no specific treatments exist, prevention of AKI is of high importance. The BigpAK-2 study investigates a promising approach to prevent AKI after major surgery.

Trial registration

The trial was registered prior to start at clinicaltrials.gov; NCT04647396.

Incidence, risk factors and outcome of postoperative acute kidney injury in China

BACKGROUND

Postoperative acute kidney injury (AKI) is a common condition after surgery, however, the available data about nationwide epidemiology of postoperative AKI in China from large and high-quality studies are limited. This study aimed to determine the incidence, risk factors and outcomes of postoperative AKI among patients undergoing surgery in China.

METHODS

This was a large, multicentre, retrospective study performed in 16 tertiary medical centres in China. Adult patients (≥18 years of age) who underwent surgical procedures from 1 January 2013 to 31 December 2019 were included. Postoperative AKI was defined by the Kidney Disease: Improving Global Outcomes creatinine criteria. The associations of AKI and in-hospital outcomes were investigated using logistic regression models adjusted for potential confounders.

RESULTS

Among 520 707 patients included in our study, 25 830 (5.0%) patients developed postoperative AKI. The incidence of postoperative AKI varied by surgery type, which was highest in cardiac (34.6%), urologic (8.7%) and general (4.2%) surgeries. A total of 89.2% of postoperative AKI cases were detected in the first 2 postoperative days. However, only 584 (2.3%) patients with postoperative AKI were diagnosed with AKI on discharge. Risk factors for postoperative AKI included older age, male sex, lower baseline kidney function, pre-surgery hospital stay ≤3 days or >7 days, hypertension, diabetes mellitus and use of proton pump inhibitors or diuretics. The risk of in-hospital death increased with the stage of AKI. In addition, patients with postoperative AKI had longer lengths of hospital stay (12 versus 19 days) and were more likely to require intensive care unit care (13.1% versus 45.0%) and renal replacement therapy (0.4% versus 7.7%).

CONCLUSIONS

Postoperative AKI was common across surgery type in China, particularly for patients undergoing cardiac surgery. Implementation and evaluation of an alarm system is important for the battle against postoperative AKI.

Dexmedetomidine Attenuates Inflammation in Elderly Patients Following Major Hepatobiliary and Pancreatic Surgery: A Randomized Clinical Trial

Background

Dexmedetomidine (Dex) may have anti-inflammatory properties and potentially reduce the incidence of postoperative organ injury.

Objective

To investigate whether Dex protects pulmonary and renal function via its anti-inflammatory effects in elderly patients undergoing prolonged major hepatobiliary and pancreatic surgery.

Design and Setting

Between October 2019 and December 2020, this randomized controlled trial was carried out at a tertiary hospital in Chongqing, China.

Patients

86 patients aged 60-75 who underwent long-duration (> 4 hrs) hepatobiliary and pancreatic surgery without significant comorbidities were enrolled and randomly assigned into two groups at a 1:1 ratio.

Interventions

Patients were given either Dex or an equivalent volume of 0.9% saline (Placebo) with a loading dose of 1 μg kg-1 for 10 min, followed by 0.5 μg kg-1 hr-1 for maintenance until the end of surgery.

Main Outcome Measures

The changes in serum concentrations of interleukin-6 (IL-6) and tumour necrosis factor-α (TNF-α) were primary outcomes.

Results

At one hour postoperatively, serum IL-6 displayed a nine-fold increase (P<0.05) in the Placebo group. Administration of Dex decreased IL-6 to 278.09 ± 45.43 pg/mL (95% CI: 187.75 to 368.43) compared to the Placebo group (P=0.019; 432.16 ± 45.43 pg/mL, 95% CI: 341.82 to 522.50). However, no significant differences in TNF-α were observed between the two groups. The incidence of postoperative acute kidney injury was twice as high in the Placebo group (9.30%) compared to the Dex group (4.65%), and the incidence of postoperative acute lung injury was 23.26% in the Dex group, lower than that in the Placebo group (30.23%), although there was no statistical significance between the two groups.

Conclusion

Dex administration in elderly patients undergoing major hepatobiliary and pancreatic surgery reduces inflammation and potentially protects kidneys and lungs.

Registration

Chinese Clinical Trials Registry, identifier: ChiCTR1900024162, on 28 June 2019.

The effectiveness of dexmedetomidine for preventing acute kidney injury after surgery: a systematic review and meta-analysis

Background

Postoperative acute kidney injury (AKI) is a serious and distressing complication connected to various adverse outcomes following the surgical operation. Controversy remains regarding the dexmedetomidine's preventive impact on postoperative AKI. Therefore, this investigation aims to explore the efficiency and safety of dexmedetomidine in preventing AKI after surgical operation.

Methods

We systematically searched electronic databases such as PubMed, Embase, Web of Science, and the Cochrane Library to detect eligible randomized controlled studies that used dexmedetomidine for the prevention of AKI following operation up to April 30, 2023. The main outcome evaluated was AKI incidence. The evidence quality was assessed employing the Grading of Recommendations Assessment, Development, and Evaluation.

Results

The meta-analysis included 25 trials, including 3,997 individuals. Of these, 2,028 were in the dexmedetomidine group, and 1,969 were in the control group. The result showed that patients administered dexmedetomidine significantly decreased the AKI incidence following surgical operation in contrast to the control group (risk ratio, 0.60; 95% confidence intervals, 0.45-0.78; p < 0.05; I 2 = 46%). In addition, dexmedetomidine decreased the period of hospitalization in both the intensive care unit (ICU) and the hospital while also reducing postoperative delirium (POD) occurrence. However, dexmedetomidine elevated the incidence of bradycardia but did not have a significant impact on other indicators.

Conclusion

Our meta-analysis indicates that the dexmedetomidine treatment reduces the postoperative AKI and POD risk while also shortening the time of hospitalization in the ICU and hospital. However, it is connected to an increased bradycardia risk.

Preoperative N-terminal pro-B-type natriuretic peptide and myocardial injury after stopping or continuing renin-angiotensin system inhibitors in noncardiac surgery: a prespecified analysis of a phase 2 randomised controlled multicentre trial

BACKGROUND

Patients with elevated preoperative plasma N-terminal pro-B-type natriuretic peptide (NT-proBNP >100 pg ml-1) experience more complications after noncardiac surgery. Individuals prescribed renin-angiotensin system (RAS) inhibitors for cardiometabolic disease are at particular risk of perioperative myocardial injury and complications. We hypothesised that stopping RAS inhibitors before surgery increases the risk of perioperative myocardial injury, depending on preoperative risk stratified by plasma NT-proBNP concentrations.

METHODS

In a preplanned analysis of a phase 2a trial in six UK centres, patients ≥60 yr old undergoing elective noncardiac surgery were randomly assigned either to stop or continue RAS inhibitors before surgery. The pharmacokinetic profile of individual RAS inhibitors determined for how long they were stopped before surgery. The primary outcome, masked to investigators, clinicians, and patients, was myocardial injury (plasma high-sensitivity troponin-T ≥15 ng L-1 or a ≥5 ng L-1 increase, when preoperative high-sensitivity troponin-T ≥15 ng L-1) within 48 h after surgery. The co-exposures of interest were preoperative plasma NT-proBNP (< or >100 pg ml -1) and stopping or continuing RAS inhibitors.

RESULTS

Of 241 participants, 101 (41.9%; mean age 71 [7] yr; 48% females) had preoperative NT-proBNP >100 pg ml -1 (median 339 [160-833] pg ml-1), of whom 9/101 (8.9%) had a formal diagnosis of cardiac failure. Myocardial injury occurred in 63/101 (62.4%) subjects with NT-proBNP >100 pg ml-1, compared with 45/140 (32.1%) subjects with NT-proBNP <100 pg ml -1 {odds ratio (OR) 3.50 (95% confidence interval [CI] 2.05-5.99); P<0.0001}. For subjects with preoperative NT-proBNP <100 pg ml-1, 30/75 (40%) who stopped RAS inhibitors had myocardial injury, compared with 15/65 (23.1%) who continued RAS inhibitors (OR for stopping 2.22 [95% CI 1.06-4.65]; P=0.03). For preoperative NT-proBNP >100 pg ml-1, myocardial injury rates were similar regardless of stopping (62.2%) or continuing (62.5%) RAS inhibitors (OR for stopping 0.98 [95% CI 0.44-2.22]).

CONCLUSIONS

Stopping renin-angiotensin system inhibitors in lower-risk patients (preoperative NT-proBNP <100 pg ml -1) increased the likelihood of myocardial injury before noncardiac surgery.

Discontinuation vs. continuation of renin-angiotensin system inhibition before non-cardiac surgery: the SPACE trial

BACKGROUND AND AIMS

Haemodynamic instability is associated with peri-operative myocardial injury, particularly in patients receiving renin-angiotensin system (RAS) inhibitors (angiotensin-converting-enzyme inhibitors/angiotensin II receptor blockers). Whether stopping RAS inhibitors to minimise hypotension, or continuing RAS inhibitors to avoid hypertension, reduces peri-operative myocardial injury remains unclear.

METHODS

From 31 July 2017 to 1 October 2021, patients aged ≥60 years undergoing elective non-cardiac surgery were randomly assigned to either discontinue or continue RAS inhibitors prescribed for existing medical conditions in six UK centres. Renin-angiotensin system inhibitors were withheld for different durations (2-3 days) before surgery, according to their pharmacokinetic profile. The primary outcome, masked to investigators, clinicians, and patients, was myocardial injury [plasma high-sensitivity troponin-T (hs-TnT) ≥ 15 ng/L within 48 h after surgery, or ≥5 ng/L increase when pre-operative hs-TnT ≥15 ng/L]. Pre-specified adverse haemodynamic events occurring within 48 h of surgery included acute hypertension (>180 mmHg) and hypotension requiring vasoactive therapy.

RESULTS

Two hundred and sixty-two participants were randomized to continue (n = 132) or stop (n = 130) RAS inhibitors. Myocardial injury occurred in 58 (48.3%) patients randomized to discontinue, compared with 50 (41.3%) patients who continued, RAS inhibitors [odds ratio (for continuing): 0.77; 95% confidence interval (CI) 0.45-1.31]. Hypertensive adverse events were more frequent when RAS inhibitors were stopped [16 (12.4%)], compared with 7 (5.3%) who continued RAS inhibitors [odds ratio (for continuing): 0.4; 95% CI 0.16-1.00]. Hypotension rates were similar when RAS inhibitors were stopped [12 (9.3%)] or continued [11 (8.4%)].

CONCLUSIONS

Discontinuing RAS inhibitors before non-cardiac surgery did not reduce myocardial injury, and could increase the risk of clinically significant acute hypertension. These findings require confirmation in future studies.

Improving Patient Outcomes in Abdominal Surgery

Post-operative acute kidney injury (PO-AKI) is a frequent complication described in 15% of non-cardiac surgeries, 30% of cardiac surgeries, and 52% of patients requiring intensive post-operative care [...].

An online-predictive model of acute kidney injury after pancreatic surgery

OBJECTIVE

Acute kidney injury(AKI) after pancreatic surgery is associated with increased mortality, longer hospital stays and poor prognosis. This study aims to identify the risk factors and establish an easy-to-use prediction calculator by the nomogram to predict the risk of AKI after pancreatic surgery.

METHODS

From January 2016 to June 2018, 1504 patients who underwent pancreatic surgery in our center were included in this retrospective analysis and randomly assigned to primary (1054 patients) and validation (450 patients) cohorts. The independent risk factors of AKI were identified using univariate and multivariate analyses. A risk-predicted nomogram for AKI was developed through multivariate logistic regression analysis in the primary cohort while the nomogram was evaluated in the validation cohort. Nomogram discrimination and calibration were assessed using C-index and calibration curves in the primary and validation cohorts. The clinical utility of the final nomogram was evaluated using decision curve analysis.

RESULTS

The overall incidence of AKI after pancreatic surgery was 5.3% (79/1504). Independent risk factors including smoking history, cardiovascular disease, ASA score, baseline eGFR, bilirubin＞2 ​mg/dL, undergoing pancreaticoduodenectomy, and intraoperative blood loss＞400 ​mL were identified by multivariate analysis. Nomogram revealed moderate discrimination and calibration in estimating the risk of AKI, with an unadjusted C-index of 0.79 (95 %CI, 0.73-0.85). Application of the nomogram in the validation cohort provided moderate discrimination (C-index,0.80 [95% CI, 0.72-0.88]) and good calibration. Besides, the decision curve analysis (DCA) confirmed the clinical usefulness of the nomogram.

CONCLUSIONS

An easy-to-use online prediction calculator comprised of preoperative and intraoperative factors was able to individually predict the occurrence risk of AKI among patients with pancreatic surgery, which may help identify reasonable risk judgments and develop proper treatment strategies to a certain extent.

Ureteral Stents Do Not Increase the Risk for Acute Kidney Injury After Colorectal Surgery

BACKGROUND

Ureteral stents are thought to prevent or help identify ureteral injuries. Studies suggesting that ureteral stents increase the risk of postoperative acute kidney injury show inconsistent conclusions. The large ureteral stenting volume at our institution provided a unique opportunity for granular analysis not previously reported.

OBJECTIVE

To determine whether prophylactic ureteral stenting at colorectal surgery increases acute kidney injury.

DESIGN

Retrospective analysis of colorectal operations with prophylactic ureteral stents was compared to operations without stents. Adjusted analysis was performed with inverse probability treatment weighting.

SETTINGS

Single institution enhanced recovery colorectal surgery service.

PATIENTS

Prospective institutional database between July 1, 2018, and December 31, 2021.

MAIN OUTCOME MEASURE

The primary outcome was acute kidney injury, defined as increase in creatinine ≥0. 3 mg/dL (definition 1) and 1.5-fold increase in creatinine (definition 2) within 48 hours postoperatively.

RESULTS

There were 410 patients in the study population: 310 patients in the stent group and 100 in the no-stent group. There were 8 operative ureteral injuries: 4 (1.29%) in the stent group and 4 (4.0%) in the no-stent group ( p = 0.103). Unadjusted analysis revealed no significant difference in acute kidney injury between groups. After adjustment, there was still no significant difference in acute kidney injury between groups when defined as definition 1 (no-stent 23.76% vs stent 26.19%, p = 0.745) and as definition 2 (no-stent 15.86% vs stent 14.8%, p = 0.867). Subgroup analysis showed that lighted stents were associated with significantly more acute kidney injury than no-stent patients when defined as definition 1 ( p = 0.017) but not when defined as definition 2 ( p = 0.311).

LIMITATIONS

Single-institution results may not be generalizable.

CONCLUSION

Prophylactic ureteral stenting does not increase the risk of acute kidney injury for patients undergoing enhanced recovery colorectal surgery, although caution and further study may be warranted for lighted stents. Studies further examining contrasting roles of ureter stenting and imaging in open and minimally invasive colorectal surgery are warranted. See Video Abstract.

LOS STENTS URETERALES NO AUMENTAN EL RIESGO DE LESIN RENAL AGUDA DESPUS DE LA CIRUGA COLORECTAL

ANTECEDENTES:Se cree que los stents ureterales previenen o ayudan a identificar las lesiones ureterales. Los estudios que sugieren que los stents ureterales aumentan el riesgo de lesión renal aguda post operatoria muestran conclusiones contradictorias. El gran volumen de endoprótesis ureterales en nuestra institución brindó una oportunidad única para el análisis granular que no se informó anteriormente.OBJETIVO:Determinar si la colocación de stent ureteral profiláctico en cirugía colorrectal aumenta el daño renal agudo.DISEÑO:El análisis retrospectivo de operaciones colorrectales con stents ureterales profilácticos se comparó con operaciones sin stents. El análisis ajustado se realizó con ponderación de tratamiento de probabilidad inversa.AJUSTES:Cirugía colorrectal de recuperación mejorada de una sola instituciónPACIENTES:Base de datos institucional prospectiva entre el 01/07/2018 y el 31/12/2021.MEDIDA DE RESULTADO PRINCIPAL:El resultado primario fue la lesión renal aguda definida como un aumento en la creatinina ≥ 0,3 mg/dL (Definición n.° 1) y un aumento de 1,5 veces en la creatinina (Definición n.° 2) dentro de las 48 horas posteriores a la operación.RESULTADOS:Hubo 410 pacientes en la población de estudio: 310 pacientes en el grupo Stent y 100 en el grupo No-Stent. Hubo 8 lesiones ureterales operatorias, 4 (1,29%) en el grupo Stent y 4 (4,0%) en el grupo No-Stent (p = 0,103). El análisis no ajustado no reveló diferencias significativas en la lesión renal aguda entre los grupos. Después del ajuste, todavía no hubo una diferencia significativa en la lesión renal aguda entre los grupos cuando se definió como Definición n.º 1 (sin stent 23,76 % frente a stent 26,19 %, p = 0,745) y por definición n.º 2 (sin stent 15,86 % frente a stent 14,8 %, p = 0,867). El análisis de sub grupos mostró que los stents iluminados se asociaron con una lesión renal aguda significativamente mayor que los pacientes sin stent cuando se definieron como Definición n.º 1 (p = 0,017), pero no cuando se los definió como Definición n.º 2 (p = 0,311).LIMITACIONES:Los resultados de una sola institución pueden no ser generalizables.CONCLUSIÓN:La colocación profiláctica de endoprótesis ureterales no aumenta el riesgo de lesión renal aguda en pacientes que se someten a cirugía colorrectal de recuperación mejorada, aunque es posible que se requiera precaución y estudios adicionales para las endoprótesis iluminadas. Se justifican estudios que examinen más a fondo las funciones contrastantes de la colocación de stents de uréter y las imágenes en la cirugía colorrectal abierta y mínimamente invasiva. (Traducción-Dr. Mauricio Santamaria ).

Association between postoperative hypotension and acute kidney injury after noncardiac surgery: a historical cohort analysis

PURPOSE

The extent to which postoperative hypotension contributes to renal injury remains unclear, much less what the harm thresholds might be. We therefore tested the primary hypothesis that there is an absolute hypotensive arterial pressure threshold for acute kidney injury during the initial seven days after noncardiac surgery.

METHODS

We conducted a single-centre historical cohort analysis of adults who had noncardiac surgery and had creatinine recorded preoperatively and postoperatively. Our exposure was the lowest postoperative mean arterial pressure, defined as the average of the three lowest postoperative pressure measurements. Our primary analysis was the association between the lowest mean arterial pressure and acute kidney injury, defined according to Kidney Disease: Improving Global Outcomes initiative criteria. Our analysis was adjusted for potentially relevant confounding factors including intraoperative hypotension.

RESULTS

Among 64,349 patients analyzed, 2,812 (4.4%) patients had postoperative acute kidney injury. Each 5-mm Hg decrease in the lowest mean arterial pressure was associated with a 28% (97.5% confidence interval [CI], 23 to 32; P < 0.001) increase in the odds of acute kidney injury for lowest mean arterial pressures < 80 mm Hg. Higher lowest pressures were not associated with acute kidney injury (odds ratio, 1.08; 97.5% CI, 0.99 to 1.17; P = 0.04) for each 5-mm Hg decrease in the lowest mean arterial pressure.

CONCLUSION

Postoperative hypotension, defined as the lowest postoperative mean arterial pressure < 80 mm Hg, was associated with acute kidney injury after noncardiac surgery. A prospective trial will be required to determine whether the observed association is causal and thus amenable to modification.

Impact of intraoperative fluid restriction on renal outcomes in patients undergoing robotic-assisted laparoscopic prostatectomy

Robotic-assisted laparoscopic prostatectomy (RALP) requires intraoperative fluid restriction to maintain the optimal view of the operative field during vesicourethral anastomosis and to prevent upper airway edema that may occur due to the steep Trendelenburg position. The aim of this study was to demonstrate that our fluid restriction regimen would not increase postoperative serum creatinine (sCr) levels in patients undergoing RALP. The fluid regimen involved maintaining a crystalloid infusion at 1 ml/kg/h until completion of vesicourethral anastomosis, then rapid infusion of 15 ml/kg within 30 min, followed by maintenance at 1.5 ml/kg/h until post-operative day (POD) 1. The primary outcome of this study was the change in the sCr level from baseline to POD7. Secondary outcomes were the sCr levels on PODs 1 and 2, the surgical view during vesicourethral anastomosis, and the incidences of re-intubation and acute kidney injury (AKI). Sixty-six patients were eligible for the analysis. The paired t test for non-inferiority showed no significant difference in sCr levels between baseline and POD7 (mean ± standard deviation, 0.79 ± 0.14 vs. 0.80 ± 0.18 mg/dl, p < 0.001). Seven patients developed AKI on POD1, but all but one recovered on POD2. Ninety-seven percent of operations were rated as having a good view of the operative field. There were no cases of re-intubation. This study demonstrated that the fluid restriction regimen of 1 ml/kg/h until completion of vesicourethral anastomosis created a good view of the operative field during vesicourethral anastomosis without increasing postoperative sCr levels in patients undergoing RALP. Trial registration: This trial was registered in the University Hospital Medical Information Network under registration number UMIN000018088 (registration date; July 1, 2015).

Association of preoperative neutrophil-lymphocyte ratio with acute kidney injury in patients with non-cardiac surgery: difference among surgical types

PURPOSE

To examine the relationship between Neutrophil-Lymphocyte Ratio (NLR) and Acute Kidney Injury (AKI) in patients undergoing noncardiac surgery, and subgroup analysis was performed for different types of non-cardiac surgery.

METHODS

The present retrospective cohort study included 10,159 adult patients who underwent major noncardiac surgery at Nanfang Hospital, Southern Medical University, between 2008 and 2018. Postoperative AKI was defined as an increase in serum creatinine level of at least 0.3 mg/dl within 48 h, or 1.5 times higher than baseline within 7 days postoperatively according to the Kidney Disease Improving Global Outcome. The correlation between preoperative NLR and postoperative AKI was determined by stepwise multivariate logistic regression analysis, and the predictive value of NLR was evaluated by the receiver operating characteristics curve (ROC) analysis.

RESULTS

Four hundred and eighty-five (4.77%) patients developed AKI postoperatively. Preoperative NLR was independently associated with postoperative AKI in all patients undergoing non-cardiac surgery (Odds ratio [OR], 1.03; 95% confidence interval [CI], 1.00-1.06). The optimal cut-off value of NLR was 2.12 according ROC analysis. The OR and 95% CI of AKI for NLR > 2.12 was 1.48 (1.21-1.81) compared with NLR ≤ 2.12. In addition, the positive association was mainly shown in patients undergone digestive system surgery with a cut-off value of 2.12 but not in neurological and musculoskeletal system surgeries.

CONCLUSION

The present study confirmed the association of preoperative NLR with postoperative AKI in digestive system surgical patients. A NLR value of 2.12 may be a useful cut-off to evaluate the risk of AKI.

Preoperative urine neutrophil gelatinase-associated lipocalin predicts mortality in colorectal cancer patients after laparoscopic surgery: A single-center study

Purpose

To determine the rate of acute kidney injury (AKI) after laparoscopic colorectal cancer (CRC) surgery and the predictive value of urine neutrophil gelatinase-associated lipocalin (uNGAL) for postoperative AKI and mortality during 3 years of follow-up.

Methods

A total of 216 CRC patients who had undergone laparoscopic surgery were included in our study. We divided all patients into two groups, including group 1 (n = 31) with postoperative AKI and group 2 (n = 185) without postoperative AKI. Urine NGAL was measured using the ELISA technique. Clinical and laboratory data were collected the day before surgery. Postoperative AKI included events occurring within 7 days of the index operation, and mortality was obtained during 3 years of follow-up.

Results

The ratio of postoperative AKI was 14.35% (31/216 patients). The urine NGAL level in group 1 was significantly higher than in group 2, p < 0.001. At cut-off value = 14.94 ng/mL, uNGAL has a predictive value for AKI (area under the curve [AUC] = 0.858, p < 0.001). After 3 years of follow-up, the total mortality rate was 7.9%. The mortality rate in group 1 (45.2%) was significantly higher than in group 2 (1.6%) with p < 0.001). At cut-off value = 19.85 ng/mL, uNGAL has a predictive value for mortality (AUC = 0.941, p < 0.001).

Conclusions

The rate of acute kidney injury after laparoscopic CRC surgery was 14.35%. Preoperative urine NGAL has a good predictive value for postoperative acute kidney injury and mortality during 3 years of follow-up.

Incidence, associated factors, and outcomes of acute kidney injury following placement of antibiotic bone cement spacers in two-stage exchange for periprosthetic joint infection: a comprehensive study

Background

Two-stage exchange with placement of antibiotic cement spacer (ACS) is the gold standard for the treatment of chronic periprosthetic joint infection (PJI), but it could cause a high prevalence of acute kidney injury (AKI). However, the results of the current evidence on this topic are too mixed to effectively guide clinical practice.

Methods

We retrospectively identified 340 chronic PJI patients who underwent the first-stage exchange with placement of ACS. The Kidney Disease Improving Global Outcomes guideline was used to define postoperative AKI. Multivariate logistic analysis was performed to determine the potential factors associated with AKI. Furthermore, a systematic review and meta-analysis on this topic were conducted to summarize the knowledge in the current literature further.

Results

In our cohort, the incidence of AKI following first-stage exchange was 12.1%. Older age (per 10 years, OR= 1.509) and preoperative hypoalbuminemia (OR= 3.593) were independent predictors for postoperative AKI. Eight AKI patients progressed to chronic kidney disease after 90 days. A meta-analysis including a total of 2525 PJI patients showed the incidence of AKI was 16.6%, and AKI requiring acute dialysis was 1.4%. Besides, host characteristics, poor baseline liver function, factors contributing to acute renal blood flow injury, and the use of nephrotoxic drugs may be associated with the development of AKI. However, only a few studies supported an association between antibiotic dose and AKI.

Conclusion

AKI occurs in approximately one out of every six PJI patients undergoing first-stage exchange. The pathogenesis of AKI is multifactorial, with hypoalbuminemia could be an overlooked associated factor. Although the need for acute dialysis is uncommon, the fact that some AKI patients will develop CKD still needs to be taken into consideration.

Effect of intraoperative low vs. conventional tidal volume on the incidence of postoperative acute kidney injury after noncardiac surgery: a two-center randomized clinical trial

BACKGROUND

In adults undergoing noncardiac surgery, the correlation between intraoperative tidal volume and postoperative acute kidney injury (AKI) is unclear. This study aimed to investigate the effects of low tidal volume ventilation on the incidence of postoperative AKI compared with conventional tidal volume in adults undergoing noncardiac surgery.

METHODS

This was a two-center prospective randomized controlled trial on adult patients who underwent noncardiac surgery and had a mechanical ventilation of >60 min. Patients were randomized to receive either a tidal volume of 6 mL/kg pre-predicted body weight (PBW, low tidal volume) or a tidal volume of 10 mL/kg pre-predicted body weight (conventional tidal volume). The primary outcome was the incidence of AKI after non-cardiac surgery. Appropriate statistical methods were used for this study.

RESULTS

Among the 1982 randomized patients, 943 with low tidal volume and 958 with conventional tidal volume were evaluable for the primary outcome. Postoperative AKI occurred in 12 patients (1.3%) in the low tidal volume group and 11 patients (1.1%) in the conventional tidal volume group, with an odds ratio of 0.889 (95%CI, 0.391-2.03) and a relative risk of 0.999 ([95%CI, 0.989-1.01]; P=0.804). Postoperative serum creatinine levels increased in 284 (30.0%) patients with low tidal volume compared to 316 (32.0%) patients with conventional tidal volume (P=0.251). No difference in postoperative serum creatinine levels was found between the two groups (57.5 [49.0-68.2] μmol/L vs. 58.8[50.4-69.5] μmol/L, P=0.056).

CONCLUSIONS

Among adults undergoing noncardiac surgery, low tidal volume mechanical ventilation did not significantly reduce the incidence of postoperative AKI compared with conventional tidal volume.

Perioperative Renal Ultrasonography of Arterio-to-Venous Coupling Predicts Postoperative Complications after Major Laparoscopic Urologic Surgery

Point-of-care ultrasonography (POCUS) with concomitant venous and arterial Doppler assessment enables clinicians to assess organ-specific blood supply. To date, no studies have investigated the usefulness of including a comprehensive perioperative POCUS assessment of patients undergoing major laparoscopic surgery. The primary aim of the present study was to evaluate whether the combined venous and arterial renal flow evaluation, measured at different time points of perioperative period, may represent a clinically useful non-invasive method to predict postoperative acute kidney injury (AKI) after major laparoscopic urologic surgery. The secondary outcome was represented by the development of any postoperative complication at day 7. We included 173 patients, subsequently divided for analysis depending on whether they did (n = 55) or did not (n = 118) develop postoperative AKI or any complications within the first 7 days. The main results of the present study were that: (1) the combination of arterial hypoperfusion and moderate-to-severe venous congestion inferred by POCUS were associated with worst outcomes (respectively, HR: 2.993, 95% CI: 1.522-5.884 and HR: 8.124, 95% CI: 3.542-18, p < 0.001); (2) high intra-operative abdominal pressure represents the only independent determinant of postoperative severe venous congestion (OR: 1.354, 95% CI: 1.017-1.804, p = 0.038); (3) the overall number of complications relies on the balance between arterial inflow and venous outflow in order to ensure the adequacy of peripheral perfusion; and (4) the overall reliability of splanchnic perfusion assessment by Doppler is high with a strong inter-rater reliability (ICC: 0.844, 95% CI: 0.792-0.844). The concomitant assessment of arterial and venous Doppler patterns predicts postoperative complications after major laparoscopic urologic surgery and may be considered a useful ultrasonographic biomarker to stratify vulnerable patients at risk for development of postoperative complications.

Association of Preoperative Prognostic Nutritional Index with Risk of Postoperative Acute Kidney Injury: A Meta-Analysis of Observational Studies

This meta-analysis aimed to assess the clinical association of the preoperative prognostic nutritional index (pre-PNI) with the risk of postoperative acute kidney injury. Four databases (e.g., Medline) were searched from inception to December 2022 to investigate the association between pre-PNI (i.e., low vs. high) and PO-PNI as well as the correlation between pre-PNI and other postoperative prognostic indices. Overall, 13 observational studies, including 9185 patients, were eligible for analysis. A low PNI was related to increased risks of PO-AKI [odd ratio (OR) = 1.65, p = 0.001, 3811 patients], postoperative infection (OR = 2.1, p < 0.00001, 2291 patients), and mortality (OR = 1.93, p < 0.0001, 2159 patients). Albeit statistically nonsignificant, a trend was noted, linking a low PNI to higher risks of postoperative bleeding (OR = 2.5, p = 0.12, 1157 patients) and stroke (OR = 1.62, p = 0.07, 2036 patients). Pooled results revealed a prolonged intensive care unit (ICU) stay in patients with low PNIs compared to those with high PNIs (MD: 0.98 days, p = 0.02, 2209 patients) without a difference in hospital stay between the two groups (MD: 1.58 days, p = 0.35, 2249 patients). This meta-analysis demonstrated an inverse correlation between PNI and the risks of PO-AKI, postoperative infection, and mortality, as well as the length of ICU stay, which warrants further investigations for verification.

Influence of hyperthermic intraperitoneal chemotherapy on renal blood perfusion

PURPOSE

Hyperthermic intraperitoneal chemotherapy (HIPEC) is accompanied with an increased risk of acute kidney injury (AKI). Whether AKI is induced by chemotoxicity or hyperthermia-related changes in renal perfusion remains controversial. The influence of HIPEC on renal perfusion has not been evaluated in patients yet.

METHODS

Renal blood perfusion was assessed in ten patients treated with HIPEC by intraoperative renal Doppler pulse-wave ultrasound. Ultrasound (US) examinations were performed pre-, intra-, and postoperative with analyses of time-velocity curves. Patient demographics, surgical details, and data regarding renal function were recorded perioperatively. For evaluation of renal Doppler US to predict AKI, patients were divided in two groups with (AKI +) and without (AKI -) kidney injury.

RESULTS

Throughout HIPEC perfusion, neither significant nor consistent changes in renal perfusion could be observed. Postoperative AKI occurred in 6 of 10 participating patients. Intraoperative renal resistive index (RRI) values > 0.8 were observed in one patient developing stage 3 AKI according KDIGO criteria. At 30 min in perfusion, RRI values were significantly higher in AKI + patients.

CONCLUSION

AKI is a common and frequent complication after HIPEC, but underlying pathophysiology remains elusive. High intraoperative RRI values may indicate an increased risk of postoperative AKI. Present data challenges the relevance of hyperthermia-derived hypothesis of renal hypoperfusion with prerenal injury during HIPEC. More attention should be drawn towards chemotoxic-induced hypothesis of HIPEC-induced AKI and caution applying regimens containing nephrotoxic agents in patients. Further confirmatory and complementary studies on renal perfusion as well as pharmacokinetic HIPEC studies are required.

Organ Protection by Caloric Restriction Depends on Activation of the De Novo NAD+ Synthesis Pathway

SIGNIFICANCE STATEMENT

AKI is a major clinical complication leading to high mortality, but intensive research over the past decades has not led to targeted preventive or therapeutic measures. In rodent models, caloric restriction (CR) and transient hypoxia significantly prevent AKI and a recent comparative transcriptome analysis of murine kidneys identified kynureninase (KYNU) as a shared downstream target. The present work shows that KYNU strongly contributes to CR-mediated protection as a key player in the de novo nicotinamide adenine dinucleotide biosynthesis pathway. Importantly, the link between CR and NAD+ biosynthesis could be recapitulated in a human cohort.

BACKGROUND

Clinical practice lacks strategies to treat AKI. Interestingly, preconditioning by hypoxia and caloric restriction (CR) is highly protective in rodent AKI models. However, the underlying molecular mechanisms of this process are unknown.

METHODS

Kynureninase (KYNU) knockout mice were generated by Clustered Regularly Interspaced Short Palindromic Repeats (CRISPR) and comparative transcriptome, proteome and metabolite analyses of murine kidneys pre- and post-ischemia-reperfusion injury in the context of CR or ad libitum diet were performed. In addition, acetyl-lysin enrichment and mass spectrometry were used to assess protein acetylation.

RESULTS

We identified KYNU as a downstream target of CR and show that KYNU strongly contributes to the protective effect of CR. The KYNU-dependent de novo nicotinamide adenine dinucleotide (NAD+) biosynthesis pathway is necessary for CR-associated maintenance of NAD+ levels. This finding is associated with reduced protein acetylation in CR-treated animals, specifically affecting enzymes in energy metabolism. Importantly, the effect of CR on de novo NAD+ biosynthesis pathway metabolites can be recapitulated in humans.

CONCLUSIONS

CR induces the de novo NAD+ synthesis pathway in the context of IRI and is essential for its full nephroprotective potential. Differential protein acetylation may be the molecular mechanism underlying the relationship of NAD+, CR, and nephroprotection.

Association of Preoperative Neutrophil-to-Lymphocyte Ratio with Postoperative Acute Kidney Injury and Mortality Following Major Noncardiac Surgeries

BACKGROUND

Acute kidney injury (AKI) is a major complication that occurs following an operation. Therefore, there is an increasing need to discover new predictors of AKI. We hypothesized that the preoperative neutrophil-to-lymphocyte ratio (NLR) was associated with postoperative AKI and in-hospital mortality following noncardiac surgery.

METHODS

This is a retrospective observational study of patients who underwent noncardiac surgery at Sichuan University West China Hospital from 2018 to 2020. Multivariable logistic regression was performed as the major analytic method. In addition, sensitivity and subgroup analyses were performed to validate the results.

RESULTS

A total of 44,065 patients were included in this study. The prevalence of postoperative AKI was 5.62%, and the in-hospital mortality was 1.58%. Multivariable analysis demonstrated that NLR ≥ 5 was independently associated with the development of postoperative AKI (OR 1.42, 1.24-1.73; P < 0.001) and in-hospital mortality (OR 2.03, 1.63-2.52; P < 0.001). Similar results were achieved when propensity-score matching was performed for patients with NLR ≥ 5 and < 5 on the baseline. In stratified analysis, the associations remained persistent in most subgroups. For the sensitivity analysis, we took NLR as a continuous variable and demonstrated the potential linear relationship between NLR and postoperative AKI and mortality.

CONCLUSIONS

Our results indicated that preoperative NLR is associated with the prevalence of postoperative AKI and in-hospital mortality that occur after major noncardiac surgery. These findings suggest that NLR has the potential to be a significant correlation biomarker associated with perioperative risk assessment of patients undergoing noncardiac surgeries.

Biomarker-guided intervention to prevent acute kidney injury after major surgery (BigpAK-2 trial): study protocol for an international, prospective, randomised controlled multicentre trial

INTRODUCTION

Previous studies demonstrated that the implementation of the Kidney Disease Improving Global Outcomes (KDIGO) guideline-based bundle, consisting of different supportive measures in patients at high risk for acute kidney injury (AKI), might reduce rate and severity of AKI after surgery. However, the effects of the care bundle in broader population of patients undergoing surgery require confirmation.

METHODS AND ANALYSIS

The BigpAK-2 trial is an international, randomised, controlled, multicentre trial. The trial aims to enrol 1302 patients undergoing major surgery who are subsequently admitted to the intensive care or high dependency unit and are at high-risk for postoperative AKI as identified by urinary biomarkers (tissue inhibitor of metalloproteinases 2*insulin like growth factor binding protein 7 (TIMP-2)*IGFBP7)). Eligible patients will be randomised to receive either standard of care (control) or a KDIGO-based AKI care bundle (intervention). The primary endpoint is the incidence of moderate or severe AKI (stage 2 or 3) within 72 hours after surgery, according to the KDIGO 2012 criteria. Secondary endpoints include adherence to the KDIGO care bundle, occurrence and severity of any stage of AKI, change in biomarker values during 12 hours after initial measurement of (TIMP-2)*(IGFBP7), number of free days of mechanical ventilation and vasopressors, need for renal replacement therapy (RRT), duration of RRT, renal recovery, 30-day and 60-day mortality, intensive care unit length-of-stay and hospital length-of-stay and major adverse kidney events. An add-on study will investigate blood and urine samples from recruited patients for immunological functions and kidney damage.

ETHICS AND DISSEMINATION

The BigpAK-2 trial was approved by the Ethics Committee of the Medical Faculty of the University of Münster and subsequently by the corresponding Ethics Committee of the participating sites. A study amendment was approved subsequently. In the UK, the trial was adopted as an NIHR portfolio study. Results will be disseminated widely and published in peer-reviewed journals, presented at conferences and will guide patient care and further research.

TRIAL REGISTRATION NUMBER

NCT04647396.

Silica Cross-Linked Micelle-Based Theranostic System for the Imaging and Treatment of Acute and Chronic Kidney Injury

Acute kidney injury (AKI) is a common and serious disease with high mortality and morbidity, and the persistent inflammatory environment brought about by AKI promotes its deterioration into chronic kidney disease (CKD). An efficient and timely targeted drug delivery to the renal tubules is crucial for AKI treatment. Here, we prepared silica cross-linked micelles (SCLMs) with different sizes and studied their targeting ability to the injured kidney. It is found that the SCLMs with a size of 13 nm could rapidly accumulate and remain in the damaged kidney. Immunofluorescence results confirmed that SCLMs are selectively located in the damaged tubular cells but cannot be found in healthy renal tissue. Therefore, fluorescent dye-labeled SCLMs were used for the imaging of the injured kidney, which could reflect the status of the kidney injury. Furthermore, atorvastatin, an antioxidative and anti-inflammatory drug, was loaded in SCLMs as the therapeutic agents for the treatment of ischemia/reperfusion-induced AKI and CKD. Renal function indexes, such as tubular necrosis, collagen deposition, and inflammation, were effectively improved after the treatment.

Intraoperative renal desaturation and postoperative acute kidney injury in older patients undergoing liver resection: A prospective cohort study

STUDY OBJECTIVE

To determine the association between intraoperative renal tissue desaturation as measured using near-infrared spectroscopy and increased likelihood of developing postoperative acute kidney injury (AKI) in older patients undergoing hepatectomy.

DESIGN

A multicenter prospective cohort study.

SETTING

The study was conducted at two tertiary hospitals in China from September 2020 to October 2021.

PATIENTS

157 older patients (≥ 60 years) undergoing open hepatectomy surgery.

INTERVENTIONS AND MEASUREMENTS

Renal tissue oxygen saturation was continuously monitored during operation using near-infrared spectroscopy. The exposure of interest was intraoperative renal desaturation, defined as at least 20% relative decline in renal tissue oxygen saturation from baseline. The primary outcome was postoperative AKI, defined using the Kidney Disease: Improving Global Outcomes criteria according to the serum creatinine criteria.

MAIN RESULTS

Renal desaturation occurred in 70 of 157 patients. Postoperative AKI was observed in 23% (16/70) and 8% (7/87) of patients with versus without renal desaturation. Patients with renal desaturation were at higher risk of AKI than patients without renal desaturation (adjusted odds ratio 3.41, 95% confidence interval: 1.12-10.36, p = 0.031). Predictive performance was 65.2% sensitivity and 33.6% specificity for hypotension alone, 69.6% sensitivity and 59.7% specificity for renal desaturation alone, and 95.7% sensitivity and 26.9% specificity for combined use of hypotension and renal desaturation.

CONCLUSIONS

Intraoperative renal desaturation occurred in >40% in our sample of older patients undergoing liver resection and was associated with increased risk of AKI. Intraoperative near-infrared spectroscopy monitoring enhances the detection of AKI.

Acute Kidney Injury After General Thoracic Surgery: A Systematic Review and Meta-Analysis

INTRODUCTION

The clinical importance of postoperative acute kidney injury (AKI) in patients undergoing general thoracic surgery is unclear. We aimed to systematically review the incidence, risk factors, and prognostic implications of AKI as a complication after general thoracic surgery.

METHODS

We searched PubMed, EMBASE, and the Cochrane Library from January 2004 to September 2021. Observational or interventional studies that enrolled ≥50 patients undergoing general thoracic surgery and reported postoperative AKI defined using contemporary consensus criteria were included for meta-analysis.

RESULTS

Thirty-seven articles reporting 35 unique cohorts were eligible. In 29 studies that enrolled 58,140 consecutive patients, the pooled incidence of postoperative AKI was 8.0% (95% confidence interval [CI]: 6.2-10.0). The incidence was 3.8 (2.0-6.2) % after sublobar resection, 6.7 (4.1-9.9) % after lobectomy, 12.1 (8.1-16.6) % after bilobectomy/pneumonectomy, and 10.5 (5.6-16.7) % after esophagectomy. Considerable heterogeneity in reported incidences of AKI was observed across studies. Short-term mortality was higher (unadjusted risk ratio: 5.07, 95% CI: 2.99-8.60) and length of hospital stay was longer (weighted mean difference: 3.53, 95% CI: 2.56-4.49, d) in patients with postoperative AKI (11 studies, 28,480 patients). Several risk factors for AKI after thoracic surgery were identified.

CONCLUSIONS

AKI occurs frequently after general thoracic surgery and is associated with increased short-term mortality and length of hospital stay. For patients undergoing general thoracic surgery, AKI may be an important postoperative complication that needs early risk evaluation and mitigation.

Even minor alteration of plasma creatinine after open abdominal surgery is associated with 30-day mortality: A single-centre cohort study

PURPOSE

Postoperative acute kidney injury is common and associated with increased length of hospital stay, costs and mortality. The impact from postoperative subclinical changes in plasma concentration of creatinine (p-creatinine) on postoperative mortality has received less attention. In this study, the association between the postoperative change of p-creatinine and all-cause mortality was investigated.

METHODS

A single-centre register-based, retrospective study was conducted including patients ≥60 years undergoing open abdominal surgery from 2000 to 2013. Postoperative p-creatinine change was analysed for association with 30-day mortality following adjustment for age, gender, surgical setting and surgical procedure. Main findings A total of 3,460 patients were included in the study of whom 67.6% underwent emergency surgery. The 30-day mortality rate was 18.3%, and a given 10μmol/L daily postoperative increase in p-creatinine was associated with an increased mortality risk with an odds ratio (OR) of 2.67 (95% CI; 2.28-3.14, P<0.001). In patients undergoing emergency surgery, a daily 10μmol/L increase in p-creatinine increased the risk for a fatal outcome a 2.39 OR (CI 95%; 2.05-2.78), P<0.001). In patients undergoing elective surgery, a similar increase in p-creatinine increased risk of postoperative death with a 28.85 OR (CI 95%; 10.25-81.19).

CONCLUSION

Even a minor postoperative p-creatinine increase following open abdominal surgery below the criteria for acute kidney injury was associated with increased 30-day mortality in patients aged 60 years or above.

Incidence and Associations of Acute Kidney Injury after General Thoracic Surgery: A System Review and Meta-Analysis

(1) Background: Acute kidney injury (AKI) is related to adverse outcomes in critical illness and cardiovascular surgery. In this study, a systematic literature review and meta-analysis was carried out to evaluate the incidence and associations of AKI as a postoperative complication of thoracic (including lung resection and esophageal) surgical procedures. (2) Methods: Adopting a systematic strategy, the electronic reference databases (PubMed, EMBASE, and Cochrane Library) were searched for articles researching postoperative renal outcomes that were diagnosed using RIFLE, AKIN or KDIGO consensus criteria in the context of a thoracic operation. A random-effects model was applied to estimate the incidence of AKI and, where reported, the pooled relative risk of mortality and non-renal complications after AKI. The meta-analysis is registered in PROSPERO under the number CRD42021274166. (3) Results: In total, 20 studies with information gathered from 34,826 patients after thoracic surgery were covered. Comprehensively, the incidence of AKI was estimated to be 8.8% (95% CI: 6.7−10.8%). A significant difference was found in the mortality of patients with and without AKI (RR = 2.93, 95% CI: 1.79−4.79, p < 0.001). Additionally, in patients experiencing AKI, cardiovascular and respiratory complications were more common (p = 0.01 and p < 0.001, respectively). (4) Conclusions: AKI is a common complication associated with adverse outcomes following general thoracic surgery. An important issue in perioperative care, AKI should be considered as a highly significant prognostic indicator and an attractive target for potential therapeutic interventions, especially in high-risk populations.

Risk factors for and prognostic values of postoperative acute kidney injury after pancreaticoduodenectomy for pancreatic ductal adenocarcinoma: A retrospective, propensity score‐matched cohort study of 1312 patients

BACKGROUND

While an association between postoperative acute kidney injury (AKI) and adverse events exists, the incidence and impact of postoperative AKI after pancreaticoduodenectomy for pancreatic ductal adenocarcinoma remain unclear. This study aimed to diagnose AKI and investigate the risk factors for and prognostic value of postoperative AKI.

METHODS

Clinical characteristics of patients who underwent pancreaticoduodenectomy between 2013 and 2020 at a high-volume centre were collected retrospectively. The Kidney Disease Improving Global Outcomes criteria were used to diagnose AKI. A 1:2 propensity score matching (PSM) was used to minimise bias between the AKI and non-AKI groups. Short-term surgical and long-term survival outcomes were compared between groups. Multivariate logistic regression analysis assessed the independent risk factors for AKI development, major complications, and 30-day mortality.

RESULTS

Postoperative AKI occurred in 10.7% of 1312 patients. Total bilirubin level > 250 μmol/L (odds ratio [OR]: 3.24; p < 0.001), estimated glomerular filtration rate < 60 ml/min/1.73 m² (OR: 2.30; p = 0.048), and intraoperative estimated blood loss >1000 ml (OR: 2.96; p = 0.001) were independent risk factors for postoperative AKI. After PSM, higher incidences of major complications (p < 0.001) and 30-day mortality (p < 0.001) were observed in the AKI group than in the non-AKI group. There was no difference in long-term overall survival outcomes between both groups (p = 0.535). AKI was an independent predictor of major complications (OR: 3.06; p < 0.001) and 30-day mortality (OR: 2.87; p = 0.034).

CONCLUSIONS

Postoperative AKI is common after pancreaticoduodenectomy for pancreatic ductal adenocarcinoma and has a predictive effect on major complications and 30-day mortality. Therefore, prevention and proper management of postoperative AKI are required in clinical practice.

Limited clinical utility for GWAS or polygenic risk score for postoperative acute kidney injury in non-cardiac surgery in European-ancestry patients

BACKGROUND

Prior studies support a genetic basis for postoperative acute kidney injury (AKI). We conducted a genome-wide association study (GWAS), assessed the clinical utility of a polygenic risk score (PRS), and estimated the heritable component of AKI in patients who underwent noncardiac surgery.

METHODS

We performed a retrospective large-scale genome-wide association study followed by a meta-analysis of patients who underwent noncardiac surgery at the Vanderbilt University Medical Center ("Vanderbilt" cohort) or Michigan Medicine, the academic medical center of the University of Michigan ("Michigan" cohort). In the Vanderbilt cohort, the relationship between polygenic risk score for estimated glomerular filtration rate and postoperative AKI was also tested to explore the predictive power of aggregating multiple common genetic variants associated with AKI risk. Similarly, in the Vanderbilt cohort genome-wide complex trait analysis was used to estimate the heritable component of AKI due to common genetic variants.

RESULTS

The study population included 8248 adults in the Vanderbilt cohort (mean [SD] 58.05 [15.23] years, 50.2% men) and 5998 adults in Michigan cohort (56.24 [14.76] years, 49% men). Incident postoperative AKI events occurred in 959 patients (11.6%) and in 277 patients (4.6%), respectively. No loci met genome-wide significance in the GWAS and meta-analysis. PRS for estimated glomerular filtration rate explained a very small percentage of variance in rates of postoperative AKI and was not significantly associated with AKI (odds ratio 1.050 per 1 SD increase in polygenic risk score [95% CI, 0.971-1.134]). The estimated heritability among common variants for AKI was 4.5% (SE = 4.5%) suggesting low heritability.

CONCLUSION

The findings of this study indicate that common genetic variation minimally contributes to postoperative AKI after noncardiac surgery, and likely has little clinical utility for identifying high-risk patients.

Preoperative dipstick albuminuria is associated with acute kidney injury in high-risk patients following non-cardiac surgery: a single-center prospective cohort study

PURPOSE

This study aimed to investigate the association between preoperative dipstick albuminuria (DA) and acute kidney injury (AKI) in high-risk patients following non-cardiac surgery.

METHODS

This was a single-center prospective cohort study. Adult patients with high risk of AKI undergoing non-cardiac surgery were enrolled. The primary outcome was AKI, defined according to KDIGO criteria within 7 days following non-cardiac surgery. DA status was determined by urinalysis performed within 24 h of hospital admission. Multivariate logistic regression model was used to analyze the association between preoperative DA and postoperative AKI.

RESULTS

During the study period, 552 patients were enrolled and 8.5% of them developed postoperative AKI. The overall rate of preoperative positive DA was 26.4% with 30 and ≥ 100 mg/dL DA accounting for 19.2% and 7.2%, respectively. Patients with more severe preoperative DA had much higher rate of postoperative AKI (5.2% in patients with negative or trace DA, 13.2% in patients with 30 mg/dL DA and 30.0% in patients with ≥ 100 mg/dL DA, P < 0.001). After adjusting for several perioperative variables, preoperative 30 mg/dL DA (OR 2.575; 95% CI 1.049-6.322; P = 0.039) and ≥ 100 mg/dL DA (OR 3.868; 95% CI 1.246-12.010; P = 0.019) showed an independent association with postoperative AKI. In addition, patients with higher DA status demonstrated significantly increased level of postoperative urine biomarkers and their ratio to urine creatinine.

CONCLUSIONS

Preoperative DA was independently associated with AKI in high-risk patients following non-cardiac surgery. Preoperative routine urinalysis for determination of DA status was suggested in early risk stratification.

Failure to Rescue After Severe Acute Kidney Injury in Patients Undergoing Non-Cardiac Surgery

INTRODUCTION

Many deaths after surgery can be attributed to "failure to rescue," which may be a better surgical quality indicator than the occurrence of a postoperative complication. Acute kidney injury (AKI) is one such postoperative complication associated with high mortality. The purpose of this study is to identify perioperative risk factors associated with failure to rescue among patients who develop postoperative AKI.

METHODS

We identified adult patients who underwent non-cardiac surgery between 2012 and 2018 and experienced postoperative severe AKI (an increase in blood creatinine concentration of >2 mg/dL above baseline or requiring hemodialysis) from the American College of Surgeons National Surgical Quality Improvement Program database. Multivariable logistic regression was used to identify risk factors for failure to rescue among patients who developed severe AKI.

RESULTS

Among 5,765,904 patients who met inclusion criteria, 26,705 (0.46%) patients developed postoperative severe AKI, of which 6834 (25.6%) experienced failure to rescue. Risk factors with the strongest association (adjusted odds ratio >1.5) with failure to rescue in patients with AKI included advanced age, higher American Society of Anesthesiologists class, presence of preoperative ascites, disseminated cancer, septic shock, and blood transfusion within 72 h of surgery start time.

CONCLUSIONS

About one-fourth of patients who develop severe AKI after non-cardiac surgery die within 30 d of surgery. Both patient- and surgery-related risk factors are associated with this failure to rescue. Further studies are needed to identify early and effective interventions in high-risk patients who develop postoperative severe AKI to prevent the antecedent mortality.

Preoperative NT-proBNP and LVEF for the prediction of acute kidney injury after noncardiac surgery: a single-centre retrospective study

BACKGROUND

Acute kidney injury (AKI) is one of the most common postoperative complications in noncardiac surgical patients, has an important impact on prognosis and is difficult to predict. Whether preoperative N-terminal pro-brain natriuretic peptide (NT-proBNP) concentrations and left ventricular ejection fraction (LVEF) levels can predict postoperative AKI in noncardiac surgical patients is unclear.

METHODS

We included 3,314 patients who underwent noncardiac surgery and had measurements of preoperative NT-proBNP concentrations and LVEF levels at a tertiary academic hospital in China between 2008 and 2018. Multiple logistic regression analysis was used to construct a postoperative AKI risk prediction model for this cohort. Then, NT-proBNP concentrations and LVEF levels were included in the abovementioned model as independent variables, and the predictive ability of these two models was compared.

RESULTS

Postoperative AKI occurred in 223 (6.72%) patients within 1 week after surgery. Preoperative NT-proBNP concentrations and LVEF levels were independent predictors of AKI after adjustment for clinical variables. The area under the receiver operating characteristic curve (AUROC) of the AKI risk predictive model established with clinical baseline variables was 0.767 (95% CI: 0.732, 0.802). When NT-proBNP concentrations and LVEF levels were added to the base model, the AUROC was 0.811 (95% CI: 0.779, 0.843). The addition of NT-proBNP concentrations and LVEF levels improved reclassification by 22.9% (95% CI 10.5-34.4%) for patients who developed postoperative AKI and by 36.3% (95% CI 29.5-43.9%) for those who did not, resulting in a significant overall improvement in net reclassification (NRI: 0.591, 95% CI 0.437-0.752, P < 0.000). The integral discrimination improvement was 0.100 (95% CI: 0.075, 0.125, P < 0.000).The final postoperative AKI prediction model was constructed, and had a good discriminative ability and fitted to the dataset.

CONCLUSIONS

Preoperative NT-proBNP concentrations and LVEF levels were independently associated with the risk of AKI after noncardiac surgery, and they could improve the predictive ability of logistic regression models based on conventional clinical risk factors.

TRIAL REGISTRATION

The protocol was preregistered in the Chinese Clinical Trial Registry ( ChiCTR1900024056 ).

The Predictive Value of Pre-operative N-Terminal Pro-B-Type Natriuretic Peptide in the Risk of Acute Kidney Injury After Non-cardiac Surgery

Objective

To evaluate the association between N-terminal pro-B-type natriuretic peptide (NT-proBNP) and risk of post-operative acute kidney injury (PO-AKI).

Methods

The electronic medical records and laboratory results were obtained from 3,949 adult patients (≥18 years) undergoing non-cardiac surgery performed between 1 October 2012 to 1 October 2019 at the Third Xiangya Hospital, Central South University, China. Collected data were analyzed retrospectively.

Results

In all, 5.3% (209 of 3,949) of patients developed PO-AKI. Pre-operative NT-proBNP was an independent predictor of PO-AKI. After adjustment for significant variables, OR for AKI of highest and lowest NT-proBNP quintiles was 1.96 (95% CI, 1.04–3.68, P = 0.008), OR per 1-unit increment in natural log transformed NT-proBNP was 1.20 (95% CI, 1.09–1.32, P < 0.001). Compared with clinical variables alone, the addition of NT-proBNP modestly improved the discrimination [change in area under the curve(AUC) from 0.82 to 0.83, ΔAUC=0.01, P = 0.024] and the reclassification (continuous net reclassification improvement 0.15, 95% CI, 0.01–0.29, P = 0.034, improved integrated discrimination 0.01, 95% CI, 0.002–0.02, P = 0.017) of AKI and non-AKI cases.

Conclusions

Results from our retrospective cohort study showed that the addition of pre-operative NT-proBNP concentrations could better predict post-operative AKI in a cohort of non-cardiac surgery patients and achieve higher net benefit in decision curve analysis.

Intraoperative hypotension is associated with persistent acute kidney disease after noncardiac surgery: a multicentre cohort study

BACKGROUND

Whilst intraoperative hypotension is associated with postoperative acute kidney injury (AKI), the link between intraoperative hypotension and acute kidney disease (AKD), defined as continuing renal dysfunction for up to 3 months after exposure, has not yet been studied.

METHODS

We conducted a retrospective multicentre cohort study using data from noncardiac, non-obstetric surgery extracted from a US electronic health records database. Primary outcome was the association between intraoperative hypotension, at three MAP thresholds (≤75, ≤65, and ≤55 mm Hg), and the following two AKD subtypes: (i) persistent (initial AKI incidence within 7 days of surgery, with continuation between 8 and 90 days post-surgery) and (ii) delayed (renal impairment without AKI within 7 days, with AKI occurring between 8 and 90 days post-surgery). Secondary outcomes included healthcare resource utilisation for patients with either AKD subtype or no AKD.

RESULTS

A total of 112 912 surgeries qualified for the study. We observed a rate of 2.2% for delayed AKD and 0.6% for persistent AKD. Intraoperative hypotension was significantly associated with persistent AKD at MAP ≤55 mm Hg (hazard ratio 1.1; 95% confidence interval: 1.38-1.22; P<0.004). However, IOH was not significantly associated with delayed AKD across any of the MAP thresholds. Patients with delayed or persistent AKD had higher healthcare resource utilisation across both hospital and intensive care admissions, compared with patients with no AKD.

CONCLUSIONS

Intraoperative hypotension is associated with persistent but not delayed acute kidney disease. Both types of acute kidney disease appear to be associated with increased healthcare utilisation. Correction of intraoperative hypotension is a potential opportunity to decrease postoperative kidney injury and associated costs.

Acute Kidney Injury and 3-Year Mortality in Elderly Patients After Non-cardiac Surgery

Objective

The present study aimed to investigate whether acute kidney injury (AKI) was associated with 3-year mortality in elderly patients after non-cardiac surgery.

Methods

The present study was a 3-year follow-up study of two randomized controlled trials. A total of 1,319 elderly patients who received non-cardiac surgery under general anesthesia were screened. AKI was diagnosed by the elevation of serum creatinine within a 7-day postoperative period according to Kidney Disease: Improving Global Outcomes (KDIGO) guidelines. A long-term telephonic follow-up was undertaken by investigators who were not involved in the previous two trials and had no access to the study group assignment. The date of death was taken from the official medical death certificate. The primary outcome was to investigate the association between AKI and postoperative 3-year mortality using the multivariable Cox regression risk model.

Results

Of the 1,297 elderly patients (mean age 71.8 ± 7.2 years old) who were included in the study, the incidence of AKI was 15.5% (201/1297). Of the patients with AKI, 85% (170/201) were at stage 1, 10% (20/201) at stage 2, and 5% (11/201) at stage 3. The 3-year all-cause mortality was 28.9% (58/201) in patients with AKI and 24.0% (263/1,096) in patients without AKI (hazard ratio 1.247, 95% confidence interval 0.939–1.657, P = 0.128). The multivariable Cox regression showed that AKI was not associated with 3-year mortality after adjustment of confounding factors (adjusted hazard ratio 1.045, 95% confidence interval 0.780–1.401, P = 0.766).

Conclusions

AKI was a common postoperative complication, but it was not associated with 3-year mortality in elderly patients who underwent non-cardiac surgery. The low incidence of severe AKI might underestimate its underlying association with long-term mortality.

Role of proenkephalin in the diagnosis of severe and subclinical acute kidney injury during the perioperative period of liver transplantation

In recent decades, clinical research on early biomarkers of renal injury has been frequent and intensive, with proenkephalin (PENK) being indicated as a promising filtration biomarker (BM). From a cohort of 57 patients, blood samples were collected preoperatively and 48 h after liver transplantation (LT). The following BMs were analyzed: PENK, cystatin-C (CYS-C), and serum creatinine (Scr). Diagnosis of AKI was based on the KDIGO criteria. Of the 57 patients undergoing LT, 50 (88%) developed acute kidney injury (AKI) and were categorized as follows: no-AKI/mild-AKI - 21 (36.8%) and severe-AKI 36 (63.2%). During the preoperative period, only PENK was significantly higher in patients with severe AKI, with an AUC of 0.69 (CI 0.54–0.83), a cutoff of 55.30 pmol/l, a sensitivity of 0.86, a specificity of 0.52, and an accuracy of 0.75. In addition, subclinical AKI was determined preoperatively in 32 patients. Forty-eight hours after LT, PENK maintained its performance in determining severe AKI, with an AUC of 0.83 (CI 0.72–0.94), a cutoff of 119.05 pmol/l, a sensitivity of 0.81, a specificity of 0.90, and an accuracy of 0.84. PENK detected AKI 48 h earlier than serum creatinine. In a multivariate linear regression analysis, PENK was an independent predictor of severe AKI. This small study suggests that the filtration biomarker PENK shows promise for detecting AKI in patients undergoing LT, revealing greater accuracy and an earlier rise in patients with severe AKI. The combination of kidney functional and filtration BMs may aid in the management and prevention of AKI progression.

Association Between Left Ventricular Relative Wall Thickness and Acute Kidney Injury After Noncardiac Surgery

BACKGROUND

Acute kidney injury (AKI) after major noncardiac surgery is commonly attributed to cardiovascular dysfunction. Identifying novel associations between preoperative cardiovascular markers and kidney injury may guide risk stratification and perioperative intervention. Increased left ventricular relative wall thickness (RWT), routinely measured on echocardiography, is associated with myocardial dysfunction and long-term risk of heart failure in patients with preserved left ventricular ejection fraction (LVEF); however, its relationship to postoperative complications has not been studied. We evaluated the association between preoperative RWT and AKI in high-risk noncardiac surgical patients with preserved LVEF.

METHODS

Patients ≥18 years of age having major noncardiac surgery (high-risk elective intra-abdominal or noncardiac intrathoracic surgery) between July 1, 2016, and June 30, 2018, who had transthoracic echocardiography in the previous 12 months were eligible. Patients with preoperative creatinine ≥2 mg/dL or reduced LVEF (<50%) were excluded. The association between RWT and AKI, defined as an increase in serum creatinine by 0.3 mg/dL from baseline within 48 hours or by 50% within 7 days after surgery, was assessed using multivariable logistic regression adjusted for preoperative covariates. An additional model adjusted for intraoperative covariates, which are strongly associated with AKI, especially hypotension. RWT was modeled continuously, associating the change in odds of AKI for each 0.1 increase in RWT.

RESULTS

The study included 1041 patients (mean ± standard deviation [SD] age 62 ± 15 years; 59% female). A total of 145 subjects (13.9%) developed AKI within 7 days. For RWT quartiles 1 through 4, respectively, 20 of 262 (7.6%), 40 of 259 (15.4%), 39 of 263 (14.8%), and 46 of 257 (17.9%) developed AKI. Log-odds and proportion with AKI increased across the observed RWT values. After adjusting for confounders (demographics, American Society of Anesthesiologists [ASA] physical status, comorbidities, baseline creatinine, antihypertensive medications, and left ventricular mass index), each RWT increase of 0.1 was associated with an estimated 26% increased odds of developing AKI (odds ratio [OR]; 95% confidence interval [CI]) of 1.26 (1.09-1.46; P = .002). After adjusting for intraoperative covariates (length of surgery, presence of an arterial line, intraoperative hypotension, crystalloid administration, transfusion, and urine output), RWT remained independently associated with the odds of AKI (OR; 95% CI) of 1.28 (1.13-1.47; P = .001). Increased RWT was also independently associated with hospital length of stay and adjusted hazard ratio (HR [95% CI]) of 0.94 (0.89-0.99; P = .018).

CONCLUSIONS

Left ventricular RWT is a novel cardiovascular factor associated with AKI within 7 days after high-risk noncardiac surgery among patients with preserved LVEF. Application of this commonly available measurement of risk stratification or perioperative intervention warrants further investigation.

Impact of early postoperative creatinine increase on mid-term renal function after cystectomy

OBJECTIVES

To determine whether early acute kidney injury affects mid-term renal function, to identify risk factors for impaired mid-term renal function, and to highlight the evolution of plasma creatinine and estimated glomerular filtration rate in the first 12 months after cystectomy and urinary diversion.

METHODS

We conducted a single-center retrospective observational cohort study from 2000 to 2019. We included 900 consecutive patients undergoing cystectomy and urinary diversion. Patients with incomplete data and preoperative hemodialysis were excluded. Early acute kidney injury was defined as an increase in plasma creatinine of >50% or >26.5 μmol/L within 24 h after surgery. Multiple linear regression analysis was performed to model the association between risk factors and change in plasma creatinine and estimated glomerular filtration rate at 12 months.

RESULTS

Early acute kidney injury was diagnosed in 183/900 patients (20.3%) and was associated with significant mid-term plasma creatinine increase compared to preoperative value (+10.0 μmol/L [95% confidence interval -1.5, 25.0] vs +4.0 μmol/L [-7.0, 13.0]; P < 0.001). Similarly, a significant estimated glomerular filtration rate change was found (-11.2 mL/min [95% confidence interval -19.8, 0.6] vs -4.9 mL/min [-15.6, 5.3]; P < 0.001). In the linear regression model, early acute kidney injury increased creatinine at 12 months by 9.8% (estimated glomerular filtration rate: decrease by 6.2 mL/min), male sex by 12.0%. Limitations include retrospective analysis from prospectively assessed data.

CONCLUSIONS

Early acute kidney injury resulted in elevated plasma creatinine and decreased estimated glomerular filtration rate values 12 months postoperatively, albeit the clinical relevance remains questionable.

A Novel Radiomics-Based Machine Learning Framework for Prediction of Acute Kidney Injury-Related Delirium in Patients Who Underwent Cardiovascular Surgery

Acute kidney injury (AKI) can be caused by multiple etiologies and is characterized by a sudden and severe decrease in kidney function. Understanding the independent risk factors associated with the development of AKI and its early detection can refine the risk management and clinical decision-making of high-risk patients after cardiovascular surgery. A retrospective analysis was performed in a single teaching hospital between December 1, 2019, and December 31, 2020. The diagnostic performance of novel biomarkers was assessed using random forest, support vector machine, and multivariate logistic regression. The nomogram from multivariate analysis of risk factors associated with AKI indicated that only LVEF, red blood cell input, and ICUmvat contribute to AKI differentiation and that the difference is statistically significant (P < 0.05). Seven radiomics biomarkers were found among 65 patients to be highly correlated with AKI-associated delirium. The importance of the variables was determined using the multilayer perceptron model; fivefold cross-validation was applied to determine the most important delirium risk factors in radiomics of the hippocampus. Finally, we established a radiomics-based machine learning framework to predict AKI-induced delirium in patients who underwent cardiovascular surgery.