Perioperative acute kidney injury

Diastolic dysfunction and acute kidney injury in elderly patients with femoral neck fracture

Background

Femoral neck fracture is common in the elderly population. Acute kidney injury (AKI) is an important risk factor for mortality in patients who have had such fracture. We evaluated the incidence of AKI in patients who had femoral neck fracture and identified risk factors for AKI and mortality.

Methods

This was an observational cohort study including 285 patients who were ≥ 65 years of age and who underwent femoral neck fracture surgery between 2013 and 2017.

Results

The mean age was 78.63 ± 6.75 years. A total of 67 (23.5%) patients developed AKI during the hospital stay: 57 (85.1%), 5 (7.5%), and 5 (7.5%) patients were classified as having stage 1, 2, and 3 AKI, respectively. Patients with AKI had a lower baseline estimated glomerular filtration rate and higher left atrial dimension, left ventricular mass index, pulmonary artery pressure, and the ratio of early mitral inflow velocity to early diastolic mitral annulus velocity (E/e’) and were more likely to have diabetes or hypertension (HTN) (P < 0.05). The presence of HTN (odds ratio [OR], 4.570; 95% confidence interval [CI], 1.632–12.797) higher E/e’ (OR, 1.105; 95% CI, 1.019–1.198), and lower hemoglobin (OR, 0.704; 95% CI, 0.528–0.938) were independently associated with a higher risk for developing AKI. Severe AKI (OR, 24.743; 95% CI, 2.822–212.401) was associated with a higher risk of mortality.

Conclusion

Elderly patients with femoral neck fracture had a high incidence of AKI. Diastolic dysfunction was associated with AKI. Severe AKI was associated with in-hospital mortality.

Retrospective analysis of the association between intraoperative magnesium sulfate infusion and postoperative acute kidney injury after major laparoscopic abdominal surgery

Magnesium sulfate can be used as a co-adjuvant drug during the perioperative period and has multiple benefits. Recent evidence suggested that perioperative magnesium sulfate infusion may lower the risk of postoperative acute kidney injury (AKI). We investigated the association between intraoperative magnesium sulfate infusion and incidence of AKI after major laparoscopic abdominal surgery. We retrospectively analyzed the medical records of adult patients 20 years or older who underwent elective major laparoscopic abdominal surgery (>2 hours) between 2010 and 2016. We investigated the association between intraoperative magnesium sulfate infusion and the incidence of postoperative AKI until postoperative day (POD) 3 using a multivariable logistic regression analysis. We included 3,828 patients in this analysis; 357 patients (9.3%) received an intraoperative magnesium sulfate infusion and 186 patients (4.9%) developed postoperative AKI by POD 3. A multivariable logistic regression analysis showed that magnesium infusion was associated with a significant decrease (63%) in postoperative AKI (odds ratio, 0.37; 95% confidence interval, 0.14–0.94; P = 0.037). Our study suggested that intraoperative magnesium sulfate infusion is associated with a reduced risk of postoperative AKI until POD 3 for patients who underwent laparoscopic major abdominal surgery. Well-designed, prospective studies should be conducted to further substantiate these findings.

Neutrophil, lymphocyte and platelet ratio as a predictor of postoperative acute kidney injury in major abdominal surgery

BACKGROUND

Surgery is one of the leading causes of acute kidney injury (AKI) in hospitalized patients. Major abdominal surgery has the second higher incidences of AKI, after cardiac surgery. AKI results from a complex interaction between hemodynamic, toxic and inflammatory factors. The pathogenesis of AKI following major abdominal surgery is distinct from cardiac and vascular surgery. The neutrophil, lymphocytes and platelets (N/LP) ratio has been demonstrated as an inflammatory marker and an independent predictor for AKI and mortality after cardiovascular surgery. The aim of this study was to evaluate the prognostic ability of the post-operative N/LP ratio after major abdominal surgery.

METHODS

We cross-examined data of a retrospective analysis of 450 patients who underwent elective or urgent major nonvascular abdominal surgery at the Department of Surgery II of Centro Hospitalar Lisboa Norte from January 2010 to February 2011. N/LP ratio was determined using maximal neutrophil counts and minimal lymphocyte and platelet counts in the first 12 h after surgery. AKI was considered when developed within 48 h after surgery.

RESULTS

One-hundred and one patients (22.4%) developed AKI. Patients with higher N/LP ratio had an increased risk of developing postoperative AKI (6.36 ± 7.34 vs 4.33 ± 3.36, p < 0.001; unadjusted OR 1.1 (95% CI 1.04-1.16), p = 0.001; adjusted OR 1.05 (95% CI 1.00-1.10), p = 0.048). Twenty-nine patients died (6.44%). AKI was an independent predictor of mortality (20.8 vs 2.3%, p < 0.0001; unadjusted OR 11.2, 95% CI 4. 8-26.2, p < 0.0001; adjusted OR 3.56, 95% CI 1.0 2-12.43, p = 0.046). In a multivariate analysis higher N/LP ratio was not associated with increased in-hospital mortality.

CONCLUSION

Postoperative N/LP ratio was independently associated with AKI after major abdominal surgery, although there was no association with in-hospital mortality.

The Accuracy of Urinary TIMP-2 and IGFBP7 for the Diagnosis of Cardiac Surgery-Associated Acute Kidney Injury: A Systematic Review and Meta-Analysis

Background:

Tissue inhibitor of metalloproteinase 2 (TIMP-2) and insulin-like growth factor binding protein 7 (IGFBP7) are recent promising markers for identification of cardiac surgery-associated acute kidney injury (CSA-AKI). The aim of this study was systematically and quantitatively to evaluate the accuracy of urinary TIMP-2 and IGFBP7 for the diagnosis of CSA-AKI.

Methods:

Three databases including PubMed, ISI web of knowledge, and Embase were systematically searched from inception to March 2018. Two investigators conducted the processes of literature search study selection, data extraction, and quality evaluation independently. Meta-DiSc and STATA were used for all statistical analyses.

Results:

A total of 8 studies comprising 552 patients were included in this meta-analysis. Pooled sensitivity and specificity with corresponding 95% confidence intervals (CIs) were 0.79 (95% CI, 0.71-0.86, I 2 = 74.2%) and 0.76 (95% CI, 0.72-0.80, I 2 = 80.8%), respectively. Pooled positive likelihood ratio (LR), negative LR, and diagnostic odds ratio were 3.49 (95% CI, 2.44-5.00, I 2 = 61.5%), 0.31(95% CI, 0.19-0.51, I 2 = 51.8%), and 14.89 (95% CI, 7.31-30.32, I 2 = 27.9%), respectively. The area under curve estimated by summary receiver operating characteristic was 0.868 (standard error [SE] 0.032) with a Q* value of 0.799 (SE 0.032). Sensitivity analysis demonstrated that one study notably affected the stability of pooled results. One of the subgroups investigated—AKI threshold—could account for partial heterogeneity.

Conclusion:

Urinary TIMP-2 and IGFBP7 is a helpful biomarker for early diagnosis of CSA-AKI. And, the potential of this biomarker with a broader spectrum of clinical settings may be the focus of future studies.

Short- and long-term outcomes after postsurgical acute kidney injury requiring dialysis

Objective

Prompt assessment of perioperative complications is critical for the comprehensive care of surgical patients. Acute kidney injury requiring dialysis (AKI-D) is associated with high mortality, yet little is known about how long-term outcomes of patients have evolved. The association of AKI-D with postsurgical outcomes has not been well studied.

Methods

We investigated patients from the National Health Insurance Research Database and validated by the multicenter Clinical Trial Consortium for Renal Diseases cohort. All patients with AKI-D 18 years or older undergoing four major surgeries (cardiothoracic, esophagus, intestine, and liver) were retrospectively investigated (N=106,573). Patient demographics, surgery type, comorbidities before admission, and postsurgical outcomes, including the in-hospital, 30-day, and long-term mortality together with dialysis dependence were collected.

Results

AKI-D is the top risk factor for 30-day and long-term mortality after major surgery. Of 1,664 individuals with AKI-D and 6,656 matched controls, AKI-D during the hospital stay was associated with in-hospital (adjusted hazard ratio [aHR]=3.04, 95% CI 2.79–3.31), 30-day (aHR=3.65, 95% CI 3.37–3.94), and long-term (aHR=3.22, 95% CI 3.01–3.44) mortality. Patients undergoing cardiothoracic surgery (CTS) showed less in-hospital (aHR=0.85, 95% CI 0.75–0.97), 30-day (aHR=0.79, 95% CI 0.70–0.89), and long-term (aHR=0.80, 95% CI 0.72–0.90) mortality compared with non-CTS patients with AKI-D. CTS patients had a high risk of 30-day dialysis dependence (subhazard ratio [sHR]=1.67, 95% CI 1.18–2.38), but the risk of long-term dialysis dependence was similar (sHR=1.38, 95% CI 0.96–2.00) after AKI-D by taking mortality as a competing risk. Non-CTS patients had more comorbidities of sepsis, azotemia, hypoalbuminemia, and metabolic acidosis compared with CTS patients.

Conclusion

AKI exhibits paramount effects on postsurgical outcomes that extend well beyond discharge from the hospital. The goal of the perioperative assessment should include the reassurance of enhancing renal function recovery among different surgeries, and optimized follow-up is warranted in attenuating the complications after postsurgical AKI has occurred.

Acute Kidney Injury Definition and Diagnosis: A Narrative Review

Acute kidney injury (AKI) is a complex syndrome characterized by a decrease in renal function and associated with numerous etiologies and pathophysiological mechanisms. It is a common diagnosis in hospitalized patients, with increasing incidence in recent decades, and associated with poorer short- and long-term outcomes and increased health care costs. Considering its impact on patient prognosis, research has focused on methods to assess patients at risk of developing AKI and diagnose subclinical AKI, as well as prevention and treatment strategies, for which an understanding of the epidemiology of AKI is crucial. In this review, we discuss the evolving definition and classification of AKI, and novel diagnostic methods.

Acute kidney injury increases the rate of major morbidities in cytoreductive surgery and HIPEC

Introduction

Acute kidney injury (AKI) following cardiovascular surgery has been shown to increase costs and overall morbidity and mortality. The incidence, risk factors, and outcomes of AKI following other types of major surgeries have not been as well characterized. We sought to study the incidence of AKI following cytoreductive surgery (CRS) and hyperthermic intraperitoneal chemotherapy (HIPEC) per the Kidney Disease: Improving Global Outcomes (KDIGO) criteria.

Materials and methods

Patients undergoing CRS and HIPEC between 2013 and 2015 were included. Demographic and perioperative data were compared between patients who experienced AKI versus controls using appropriate statistical analysis between categorical and continuous variables. AKI was recorded by a Certified Professional in Healthcare Quality (CPHQ) and defined as a rise in serum creatinine by ≥ 0.3 mg/dL within 48 h (KDIGO criteria).

Results

Fifty-eight consecutive patients undergoing CRS and HIPEC were included. Twelve (20.7%) patients were recorded to develop AKI. This was the most common complication recorded by the CPHQ member. There was one 30-day mortality secondary to cerebral infarction. AKI patients had a longer hospitalization period (14.2 ± 6.9 vs. 9.5 ± 3.3 days, p = 0.002), and a higher rate of major complications (50.00% vs. 15.21%; p = 0.018). Readmission rate was similar (p = 0.626). Multivariate regression identified excessive blood loss during surgery as a major predictor of AKI occurrence, and pre-existing comorbidities and postoperative AKI as predictors of major morbidities following CRS and HIPEC.

Conclusion

AKI following CRS and HIPEC appears to be a common complication which is associated with further major morbidities. Current quality improvement programs may be under-reporting this incidence.

•

We aim to study the incidence of acute kidney injury and renal recovery following cytoreductive surgery (CRS) plus hyperthermic intraperitoneal chemotherapy (HIPEC) per the Kidney Disease Improving Global Outcomes (KDIGO) criteria.

•

Fifty-eight patients who underwent CRS and HIPEC at our institution were included over 2 years.

•

AKI was the most common complication leading to a longer hospitalization and a higher rate of other major complications.

•

The use of Mitomycin C as the HIPEC agent, as well as longer surgeries with increased blood loss were the only predictors of AKI occurrence. Our intra- and postoperative fluid management was not different between the AKI and non-AKI group.

Epidemiology, outcomes, and management of acute kidney injury in the vascular surgery patient

OBJECTIVE

Conventional clinical wisdom has often been nihilistic regarding the prevention and management of acute kidney injury (AKI), despite its being a frequent and morbid complication associated with both increased mortality and cost. Recent developments have shown that AKI is not inevitable and that changes in management of patients can reduce both the incidence and morbidity of perioperative AKI. The purpose of this narrative review was to review the epidemiology and outcomes of AKI in patients undergoing vascular surgery using current consensus definitions, to discuss some of the novel emerging risk stratification and prevention techniques relevant to the vascular surgery patient, and to describe a standardized perioperative pathway for the prevention of AKI after vascular surgery.

METHODS

We performed a critical review of the literature on AKI in the vascular surgery patient using the PubMed and MEDLINE databases and Google Scholar through September 2017 using web-based search engines. We also searched the guidelines and publications available online from the organizations Kidney Disease: Improving Global Outcomes and the Acute Dialysis Quality Initiative. The search terms used included acute kidney injury, AKI, epidemiology, outcomes, prevention, therapy, and treatment.

RESULTS

The reported epidemiology and outcomes associated with AKI have been evolving since the publication of consensus criteria that allow accurate identification of mild and moderate AKI. The incidence of AKI after major vascular surgery using current criteria is as high as 49%, although there are significant differences, depending on the type of procedure performed. Many tools have become available to assess and to stratify the risk for AKI and to use that information to prevent AKI in the surgical patient. We describe a standardized clinical assessment and management pathway for vascular surgery patients, incorporating current risk assessment and preventive strategies to prevent AKI and to decrease its complications. Patients without any risk factors can be managed in a perioperative fast-track pathway. Those patients with positive risk factors are tested for kidney stress using the urinary biomarker TIMP-2•IGFBP7, and care is then stratified according to the result. Management follows current Kidney Disease: Improving Global Outcomes guidelines.

CONCLUSIONS

AKI is a common postoperative complication among vascular surgery patients and has a significant impact on morbidity, mortality, and cost. Preoperative risk assessment and optimal perioperative management guided by that risk assessment can minimize the consequences associated with postoperative AKI. Adherence to a standardized perioperative pathway designed to reduce risk of AKI after major vascular surgery offers a promising clinical approach to mitigate the incidence and severity of this challenging clinical problem.

Novel preconditioning strategies for enhancing the migratory ability of mesenchymal stem cells in acute kidney injury

Acute kidney injury (AKI) remains a worldwide public health issue due to its increasing incidence, significant mortality, and lack of specific target-orientated therapy. Developments in mesenchymal stem cell (MSC) research make MSCs a promising candidate for AKI management but relevant clinical trials show confusing results (NCT00733876, NCT01602328). One primary cause of the limited therapeutic effect may result from poor engraftment of transplanted cells. To solve this problem, investigators have developed a series of preconditioning strategies to improve MSC engraftment in animal AKI models. In this review, we summarize these previous studies, providing an integrated and updated view of different preconditioning strategies aimed at promoting the therapeutic effect of MSCs in AKI patients.

Acute kidney injury in major abdominal surgery: incidence, risk factors, pathogenesis and outcomes

Acute kidney injury (AKI) is a common complication in patients undergoing major abdominal surgery. Various recent studies using modern standardized classifications for AKI reported a variable incidence of AKI after major abdominal surgery ranging from 3 to 35%. Several patient-related, procedure-related factors and postoperative complications were identified as risk factors for AKI in this setting. AKI following major abdominal surgery has been shown to be associated with poor short- and long-term outcomes. Herein, we provide a contemporary and critical review of AKI after major abdominal surgery focusing on its incidence, risk factors, pathogeny and outcomes.

Experimental MRI Monitoring of Renal Blood Volume Fraction Variations En Route to Renal Magnetic Resonance Oximetry

Diagnosis of early-stage acute kidney injury (AKI) will benefit from a timely identification of local tissue hypoxia. Renal tissue hypoxia is an early feature in AKI pathophysiology, and renal oxygenation is increasingly being assessed through T₂*-weighted magnetic resonance imaging (MRI). However, changes in renal blood volume fraction (BVf) confound renal T₂*. The aim of this study was to assess the feasibility of intravascular contrast-enhanced MRI for monitoring renal BVf during physiological interventions that are concomitant with variations in BVf and to explore the possibility of correcting renal T₂* for BVf variations. A dose-dependent study of the contrast agent ferumoxytol was performed in rats. BVf was monitored throughout short-term occlusion of the renal vein, which is known to markedly change renal blood partial pressure of O₂ and BVf. BVf calculated from MRI measurements was used to estimate oxygen saturation of hemoglobin (SO₂). BVf and SO₂ were benchmarked against cortical data derived from near-infrared spectroscopy. As estimated from magnetic resonance parametric maps of T₂ and T₂*, BVf was shown to increase, whereas SO₂ was shown to decline during venous occlusion (VO). This observation could be quantitatively reproduced in test–retest scenarios. Changes in BVf and SO₂ were in good agreement with data obtained from near-infrared spectroscopy. Our findings provide motivation to advance multiparametric MRI for studying AKIs, with the ultimate goal of translating MRI-based renal BVf mapping into clinical practice en route noninvasive renal magnetic resonance oximetry as a method of assessing AKI and progression to chronic damage.

Incidence and Risk Factors of in-hospital mortality from AKI after non-cardiovascular operation: A nationwide Survey in China

This study aimed to describe the mortality and risk factors of in-hospital mortality from acute kidney injury (AKI) after non-cardiovascular operation in China based on a nationwide survey about AKI. The study sample was drawn from ISN AKF 0by25 China Consortiums, which is a nationwide, cross-sectional survey from 22 provinces in mainland China. AKI after non-cardiovascular operation was identified according to the 2012 KDIGO AKI creatinine criteria or expanded criteria. In total, 3468 cases were identified as hospital-acquired AKI (HA-AKI). Of these, 1059 cases were defined as AKI after major non-cardiovascular surgery. Post-operative AKI and non-operative AKI were similar in aetiology and in the need for RRT intervention. The all-cause in-hospital mortality was 17.0% (180 of 1059) among patients with AKI after a major surgery. Older age (OR = 1.14, p = 0.046), more severe comorbidities (OR = 9.29, p < 0.001), a history of CVD (OR = 1.85, p = 0.007), more severe peak AKI stage, and being located in the northwest region of China (OR = 2.47, p = 0.012) were all significantly associated with increased in-hospital mortality risk in AKI patients who underwent an operation. AKI after a non-cardiovascular operation has become a huge medical burden in China. The features of operative AKI varied substantially in different regions of China. Increased attention must be paid to the occurrence of potential intrinsic renal AKI when patients are exposed to nephrotoxic factors or comorbidities.

Perioperative Acute Kidney Injury: Risk Factors and Predictive Strategies

Acute kidney injury (AKI) is a common complication in surgical patients and is associated with increases in mortality, an increased risk for chronic kidney disease and hemodialysis after discharge, and increased cost. Better understanding of the risk factors that contribute to perioperative AKI has led to improved AKI prediction and will eventually lead to improved prevention of AKI, mitigation of injury when AKI occurs, and enhanced recovery in patients who sustain AKI. The development of advanced clinical prediction scores for AKI, new imaging techniques, and novel biomarkers for early detection of AKI provides new tools toward these ends.

Analysis of Survival After Initiation of Continuous Renal Replacement Therapy in a Surgical Intensive Care Unit

IMPORTANCE

Continuous renal replacement therapy (CRRT) benefits patients with renal failure who are too hemodynamically unstable for intermittent hemodialysis. The duration of therapy beyond which continued use is futile, particularly in a population of patients admitted to and primarily cared for by a surgical service (hereinafter referred to as surgical patients), is unclear.

OBJECTIVE

To analyze proportions of and independent risk factors for survival to discharge after initiation of CRRT among patients in a surgical intensive care unit (SICU).

DESIGN, SETTING, AND PARTICIPANTS

This retrospective cohort study included all patients undergoing CRRT from July 1, 2012, through January 31, 2016, in an SICU of an urban tertiary medical center. The population included patients treated before or after general surgery and patients admitted to a surgical service during inpatient evaluation and care before liver transplant. The pretransplant population was censored from further survival analysis on receipt of a transplant.

EXPOSURES

Continuous renal replacement therapy.

MAIN OUTCOMES AND MEASURES

Hospital mortality among patients in an SICU after initiation of CRRT.

RESULTS

Of 108 patients (64 men [59.3%] and 44 women [40.7%]; mean [SD] age, 62.0 [12.7] years) admitted to the SICU, 53 were in the general surgical group and 55 in the pretransplant group. Thirteen of the 22 patients in the pretransplant group who required 7 or more days of CRRT died (in-hospital mortality, 59.1%); among the 12 patients in the general surgery group who required 7 or more days of CRRT, 12 died (in-hospital mortality, 100%). In the general surgical group, each day of CRRT was associated with an increased adjusted odds ratio of death of 1.39 (95% CI, 1.01-1.90; P = .04).

CONCLUSIONS AND RELEVANCE

Continuous renal replacement therapy is valuable for surgical patients with an acute and correctable indication; however, survival decreases significantly with increasing duration of CRRT. Duration of CRRT does not correlate with survival among patients awaiting liver transplant.

The Association of Preoperative Body Mass Index with Acute Kidney Injury in Liver Transplantation Recipients: A Retrospective Study

Background

Liver transplantation (LT) is a complicated procedure with a high incidence of postoperative acute kidney injury (AKI). Previous studies indicate that even transient or mild post-LT AKI can result in critical conditions, including prolonged stays in hospitals and intensive care units and increased morbidity and mortality. The aim of this study was to investigate the association between body mass index (BMI) and occurrence of AKI in LT recipients.

Methods

Medical data from 203 patients who received LT surgery from January 2010 to August 2016 in a single university hospital setting were retrospectively collected and analyzed. Patients were classified as either underweight (BMI <20 kg/m²) or normal weight (20 ≤ BMI < 30 kg/m²). Demographic data, anesthetic methods, complications, and perioperative laboratory test values of each patient were assessed. Propensity analyses and logistic regression were performed to evaluate the association between BMI and post-LT AKI.

Results

There was no significant difference in occurrence of post-LT AKI between underweight and normal weight patients. The underweight patient group had significantly longer hospital stay compared with the normal weight patient group (P = 0.023).

Conclusions

BMI classification was neither a positive nor negative predictor of postoperative AKI occurrence. However, patients with lower BMI had significantly longer hospital stay compared with their counterparts. Although our study was limited by its retrospective design, our observations suggest that lower BMI might play a role in post-LT AKI.

Administration of mesenchymal stromal cells before renal ischemia/reperfusion attenuates kidney injury and may modulate renal lipid metabolism in rats

Mesenchymal stromal cells (MSC) have been demonstrated to attenuate renal ischemia/reperfusion (I/R) damage in rodent models. The mechanisms of such nephro-protection remain largely unknown. Furthermore, the optimal timing of MSC administration has been poorly investigated. Here, we compare the impact of MSC injection 7 days before (MSCD - 7) versus 1 day after (MSCD + 1) renal I/R in rats. Control groups received equivalent volumes of saline at similar time-points (SD - 7 and SD + 1). Right nephrectomy was performed, and left renal ischemia lasted 45 min. After 48-hour reperfusion, we observed significantly improved renal function parameters, reduced apoptotic index and neutrophil/macrophage infiltration in kidney parenchyma, and lower expression of tubular damage markers and pro-inflammatory cytokines in MSCD - 7 in comparison to MSCD + 1 and saline control groups. Next, comparative high-throughput RNA sequencing of MSCD - 7 vs. SD - 7 non-ischemic right kidneys highlighted significant down-regulation of fatty acid biosynthesis and up-regulation of PPAR-α pathway. Such a preferential regulation towards lipid catabolism was associated with decreased levels of lipid peroxidation products, i.e. malondialdehyde and 4-hydroxy-2-nonenal, in MSCD - 7 versus SD - 7 ischemic kidneys. Our findings suggest that MSC pretreatment may exert protective effects against renal I/R by modulating lipid metabolism in rats.

Experience With Prophylactic Gentamicin During Penile Prosthesis Surgery: A Retrospective Comparison of Two Different Doses

BACKGROUND

Gentamicin has been determined to be active against a wide range of bacterial infections and has been commonly used as a preoperative antibiotic for inflatable penile prosthesis (IPP) implantation. However, the best dosing regimen to produce the safest optimal prophylactic effect remains to be determined.

AIM

To compare low- and high-dose gentamicin as prophylaxis during IPP implantation.

METHODS

We retrospectively analyzed two groups of patients who underwent IPP placement from April 14, 2012 through April 13, 2016. Group 1 was composed of 490 patients who underwent IPP placement from April 14, 2012 through April 13, 2014 and received a low dose of preoperative gentamicin at 80 mg every 8 hours for 1 day. Group 2 was composed of 407 patients who underwent IPP placement from April 14, 2014 through April 13, 2016 and received a single high dose of preoperative gentamicin at 5 mg/kg. We compared the infection rates of IPP and any gentamicin-related toxicities. The same surgeon performed all procedures. All patients received additional vancomycin 1 g before incision and at 12 hours postoperatively.

OUTCOME

Demographic data and IPP infection rate were compared and potential toxicities from the higher dose of gentamicin were closely monitored.

RESULTS

There were no significant differences in mean age, mean body mass index, and mean interval for IPP placement and IPP infection between the two groups. No toxicity was seen with the higher gentamicin dose. Six cases in group 1 (five de novo cases and one redo case, infection rate = 1.22%) and three cases in group 2 (two de novo cases and one redo case, infection rate = 0.74%) were found to have IPP infection. The infection rate in group 2 appeared to be lower than that in group 1, although a significant statistical difference was not achieved (P = .057).

CLINICAL IMPLICATIONS

These findings would help guide urologists in choosing an optimal preoperative gentamicin dose for IPP surgery.

STRENGTHS AND LIMITATIONS

This is the first study to report on the usage of high-dose preoperative gentamicin for IPP surgery but with limitations as a retrospective study.

CONCLUSIONS

Although not achieving a statistical difference, there was a trend for patients receiving a higher dose of preoperative gentamicin to have a lower IPP infection rate. No toxicity was encountered from the 5-mg/kg gentamicin dose. We recommend following prophylactic high-dose gentamicin guidelines. Xie D, Gheiler V, Lopez I, et al. Experience With Prophylactic Gentamicin During Penile Prosthesis Surgery: A Retrospective Comparison of Two Different Doses. J Sex Med 2017;14:1160-1164.

Temporal trends of dialysis requiring acute kidney injury after orthotopic cardiac and liver transplant hospitalizations

Background

The epidemiology and outcomes of acute kidney injury (AKI) in prevalent non-renal solid organ transplant recipients is unknown.

Methods

We assessed the epidemiology of trends in acute kidney injury (AKI) in orthotopic cardiac and liver transplant recipients in the United States. We used the Nationwide Inpatient Sample to evaluate the yearly incidence trends (2002 to 2013) of the primary outcome, defined as AKI requiring dialysis (AKI-D) in hospitalizations after cardiac and liver transplantation. We also evaluated the trend and impact of AKI-D on hospital mortality and adverse discharge using adjusted odds ratios (aOR).

Results

The proportion of hospitalizations with AKI (9.7 to 32.7% in cardiac and 8.5 to 28.1% in liver transplant hospitalizations; p_trend<0.01) and AKI-D (1.63 to 2.33% in cardiac and 1.32 to 2.65% in liver transplant hospitalizations; p_trend<0.01) increased from 2002-2013. This increase in AKI-D was explained by changes in race and increase in age and comorbidity burden of transplant hospitalizations. AKI-D was associated with increased odds of in hospital mortality (aOR 2.85; 95% CI 2.11-3.80 in cardiac and aOR 2.00; 95% CI 1.55-2.59 in liver transplant hospitalizations) and adverse discharge [discharge other than home] (aOR 1.97; 95% CI 1.53-2.55 in cardiac and 1.91; 95% CI 1.57-2.30 in liver transplant hospitalizations).

Conclusions

This study highlights the growing burden of AKI-D in non-renal solid organ transplant recipients and its devastating impact, and emphasizes the need to develop strategies to reduce the risk of AKI to improve health outcomes.

Electronic supplementary material

The online version of this article (doi:10.1186/s12882-017-0657-8) contains supplementary material, which is available to authorized users.

Inhaled nitric oxide prevents NSAID-induced renal impairment in pseudo-normovolaemic piglets

Objective

Inhaled nitric oxide (iNO) is commonly used as a treatment of pulmonary hypertension. Its action is purported to be specific to the lung, but extrapulmonary effects have been reported. The objective of this study was to evaluate if iNO could compensate the renal impairment induced by ketoprofen, a conventional non-steroidal anti-inflammatory drug (NSAID), during general anaesthesia.

Methods

Under pseudo-normovolaemic condition, thirty piglets were randomly assigned into 5 equal groups and equipped for renal and systemic parameters measurements. A first experiment was carried out to validate methods and reproduce the renal effects of iNO (40 ppm) in comparison with a placebo (100% oxygen). In a second experiment, iNO was inhaled for 120 minutes right after NSAID treatment (ketoprofen 2 mg×kg^-1 IV, and 40 ppm iNO; group KiNO) and its effects were compared to ketoprofen alone (2 mg×kg^-1 IV; group K) and placebo (saline; group C).

Results

In this model, iNO increased significantly renal blood flow measured by ultrasonic (RBF_UL: +53.2±17.2%; p = 0.008) and by PAH clearance (RBF_PAH:+78.6±37.6%; p = 0.004) methods, glomerular filtration rate (GFR: +72.6±32.5%; p = 0.006) and urinary output (UO: +47.4±24.2%; p = 0.01). In the second experiment, no significant temporal variation was noted for renal parameters in groups KiNO and C, whereas a significant and constant decrease was observed in the group K for RBF_UL (max -19.0±7.1%), GFR (max -26.6±10.4%) and UO (max -30.3±10.5%).

Clinical significance

Our experiments show that iNO, released from its transport forms after its inhalation, can improve renal safety of NSAIDs. This result is promising regarding the use of NSAIDs in critical conditions, but needs to receive clinical confirmation.

Postoperative acute kidney injury

Acute kidney injury (AKI) after cardiac surgery is a common and serious complication. Several definitions of AKI have been proposed recently, and include both increases in serum creatinine levels and decreases in urine output as diagnostic criteria. The pathophysiology of postoperative AKI is complex and involves both ischemic injury and systemic inflammation. Identifying risk factors, such as old age, underlying diabetes, heart failure, and obesity, may aid in the application of preventative methods for postoperative AKI. Additionally, recognizing different risks after different types of surgical procedures would be valuable. Novel biomarkers that could detect AKI more precisely at an earlier time point are being investigated. Several new biomarkers have been assessed in large multi-center studies and are believed to accommodate conventional clinical findings in diagnosing postoperative AKI. In high-risk patients, preventative measures, such as the maintenance of adequate hemodynamics and sufficient fluid resuscitation, could lower the incidence of postoperative AKI. Avoiding nephrotoxic agents and optimizing preoperative hemoglobin levels to avoid excessive transfusions would also be beneficial. In situations in which medical management fails to maintain sufficient urine output and acid-base and electrolyte homeostasis, early initiation of renal replacement therapy should be considered.

The Pattern of Longitudinal Change in Serum Creatinine and 90-Day Mortality After Major Surgery

OBJECTIVE

Calculate mortality risk that accounts for both severity and recovery of postoperative kidney dysfunction using the pattern of longitudinal change in creatinine.

BACKGROUND

Although the importance of renal recovery after acute kidney injury (AKI) is increasingly recognized, the complex association that accounts for longitudinal creatinine changes and mortality is not fully described.

METHODS

We used routinely collected clinical information for 46,299 adult patients undergoing major surgery to develop a multivariable probabilistic model optimized for nonlinearity of serum creatinine time series that calculates the risk function for 90-day mortality. We performed a 70/30 cross validation analysis to assess the accuracy of the model.

RESULTS

All creatinine time series exhibited nonlinear risk function in relation to 90-day mortality and their addition to other clinical factors improved the model discrimination. For any given severity of AKI, patients with complete renal recovery, as manifested by the return of the discharge creatinine to the baseline value, experienced a significant decrease in the odds of dying within 90 days of admission compared with patients with partial recovery. Yet, for any severity of AKI, even complete renal recovery did not entirely mitigate the increased odds of dying, as patients with mild AKI and complete renal recovery still had significantly increased odds for dying compared with patients without AKI [odds ratio: 1.48 (95% confidence interval: 1.30-1.68)].

CONCLUSIONS

We demonstrate the nonlinear relationship between both severity and recovery of renal dysfunction and 90-day mortality after major surgery. We have developed an easily applicable computer algorithm that calculates this complex relationship.

Prevention of acute kidney injury in Intensive Care Units

Acute kidney injury (AKI) is a growing concern in Intensive Care Units. The advanced age of our patients, with the increase in associated morbidity and the complexity of the treatments provided favor the development of AKI. Since no effective treatment for AKI is available, all efforts are aimed at prevention and early detection of the disorder in order to establish secondary preventive measures to impede AKI progression. In critical patients, the most frequent causes are sepsis and situations that result in renal hypoperfusion; preventive measures are therefore directed at securing hydration and correct hemodynamics through fluid perfusion and the use of inotropic or vasoactive drugs, according to the underlying disease condition. Apart from these circumstances, a number of situations could lead to AKI, related to the administration of nephrotoxic drugs, intra-tubular deposits, the administration of iodinated contrast media, liver failure and major surgery (mainly heart surgery). In these cases, in addition to hydration, there are other specific preventive measures adapted to each condition.

Acute kidney injury burden in different clinical units: Data from nationwide survey in China

Background

The inpatient morbidity and mortality of acute kidney injury (AKI) vary considerably in different clinical units, yet studies to compare the difference remain limited.

Methods

We compared the clinical characteristics of AKI in Intensive Care Unit (ICU), medical and surgical departments by using the data derived from the 2013 nationwide cross-sectional survey of AKI in China to capture variations among different clinical departments in recognition, management, and outcomes of AKI. Suspected AKI patients were identified based on changes in serum creatinine during hospitalization, and confirmed by reviewing medical records.

Results

The detection rate of AKI was the highest in ICU (22.46%), followed by the rates in medical (1.96%) and surgical departments (0.96%). However, the absolute number of cases was the largest in medical departments, which contributed to 50% of the cases. In medical departments, 78% of AKI cases were extensively distributed in cardiac, nephrology, oncology, gastroenterology, pneumology and neurology departments. In contrast, 87% of AKI cases in surgical departments were mainly from urology, general surgery and cardiothoracic departments. The in-time recognition rates were extremely low in all departments except nephrology. Only 10.5~15.0% AKI patients from non-nephrology departments received renal referral. Among all the death cases, 50% and 39% came from ICU and medical departments while only 11% from surgical departments. Older age, higher AKI stage and renal replacement therapy indication were identified as risk factors for high mortality in all departments. Delayed recognition and no renal referral were significantly associated with increased mortality in medical and ICU patients.

Conclusions

These findings suggest that ICU and medical departments are major affected departments in China with a large number of AKI cases and subsequent high mortality. The reality is more alarming considering the low awareness of AKI and the paucity of effective interventions in the high-risk patients in these departments.

A general approach to risk modeling using partial surrogate markers with application to perioperative acute kidney injury

BACKGROUND

Surrogate outcomes are often utilized when disease outcomes are difficult to directly measure. When a biological threshold effect exists, surrogate outcomes may only represent disease in specific subpopulations. We refer to these outcomes as "partial surrogate outcomes." We hypothesized that risk models of partial surrogate outcomes would perform poorly if they fail to account for this population heterogeneity. We developed criteria for predictive model development using partial surrogate outcomes and demonstrate their importance in model selection and evaluation within the clinical example of serum creatinine, a partial surrogate outcome for acute kidney injury.

METHODS

Data from 4737 patients who underwent cardiac surgery at a major academic center were obtained. Linear and mixture models were fit on maximum 2-day serum creatinine change as a surrogate for estimated glomerular filtration rate at 90 days after surgery (eGFR90), adjusted for known AKI risk factors. The AUC for eGFR90 decline and Spearman's rho were calculated to compare model discrimination between the linear model and a single component of the mixture model deemed to represent the informative subpopulation. Simulation studies based on the clinical data were conducted to further demonstrate the consistency and limitations of the procedure.

RESULTS

The mixture model was highly favored over the linear model with BICs of 2131.3 and 5034.3, respectively. When model discrimination was evaluated with respect to the partial surrogate, the linear model displays superior performance (p < 0.001); however, when it was evaluated with respect to the target outcome, the mixture model approach displays superior performance (AUC difference p = 0.002; Spearman's difference p = 0.020). Simulation studies demonstrate that the nature of the heterogeneity determines the magnitude of any advantage the mixture model.

CONCLUSIONS

Partial surrogate outcomes add complexity and limitations to risk score modeling, including the potential for the usual metrics of discrimination to be misleading. Partial surrogacy can be potentially uncovered and appropriately accounted for using a mixture model approach. Serum creatinine behaved as a partial surrogate outcome consistent with two patient subpopulations, one representing patients whose injury did not exceed their renal functional reserve and a second population representing patients whose injury did exceed renal functional reserve.

Stratification and Risk Reduction of Perioperative Acute Kidney Injury

Perioperative acute kidney injury (AKI) is associated with an increased morbidity and mortality. The incidence of AKI varies depending on preoperative risk factors and the surgical setting. Preoperative risk stratification is critical for informed consent and perioperative planning. Perioperative renal protection strategies are potentially invaluable in the prevention of AKI. Current advances in the development of biomarkers may offer the opportunity for early diagnosis and the implementation of therapeutic strategies. Increased awareness and concerted efforts by all perioperative physicians are needed to provide an improved outcome for surgical patients.

Sex and the Risk of AKI Following Cardio-thoracic Surgery: A Meta-Analysis

BACKGROUND AND OBJECTIVES

Being a woman is a well established risk factor for the development of cardiothoracic surgery-associated AKI. In striking contrast, women are less likely to develop AKI associated with noncardiac surgical procedures than men. In an attempt to ascertain why being a woman might be protective for ischemic AKI after general surgery but deleterious in patients undergoing cardiothoracic surgery, we examined cardiothoracic surgery-associated AKI in greater detail.

DESIGN, SETTING, PARTICIPANTS, & MEASUREMENTS

We performed a systematic review and meta-analysis of cardiothoracic surgery-associated AKI studies published between January of 1978 and December of 2015 to further explore the relationship between sex and cardiothoracic surgery-associated AKI.

RESULTS

Sixty-four studies were identified that provided sex-specific data regarding the incidence of cardiothoracic surgery-associated AKI among 1,057,412 subjects. Using univariate analysis, women were more likely than men to develop AKI postoperatively (odds ratio, 1.21; 95% confidence interval, 1.09 to 1.33; P<0.001). However, when the analysis was restricted to the 120,464 subjects reported in 29 studies that used the Acute Kidney Injury Network criteria, the RIFLE criteria, or the Kidney Disease Improving Global Outcomes criteria to define AKI, there was no significant sex-related difference in risk. Seventeen studies used multivariate analysis to assess risk factors for cardiothoracic surgery-associated AKI and provided sex-specific odd ratios. Among the 1,587,181 individuals included in these studies, the risk of developing cardiothoracic surgery-associated AKI was not significantly associated with sex (odds ratio, 1.04; 95% confidence interval, 0.92 to 1.19; P=0.51). However, when the analysis was restricted to the 5106 subjects reported in four studies that used the Acute Kidney Injury Network criteria to define AKI, the risk of developing AKI was significantly lower in women compared with in men (odds ratio, 0.75; 95% confidence interval, 0.65 to 0.87; P<0.001).

CONCLUSIONS

Our systematic review and meta-analysis contradict the generally held consensus that being a woman is an independent risk factor for the development of cardiothoracic surgery-associated AKI.

Acute and Chronic Kidney Disease and Cardiovascular Mortality After Major Surgery

OBJECTIVE

The aim of the study was to determine the long-term cardiovascular-specific mortality in patients with acute kidney injury (AKI) or chronic kidney disease (CKD) after major surgery.

BACKGROUND

In surgical patients, pre-existing CKD and postoperative AKI are associated with increases in all-cause mortality.

METHODS

In a single-center cohort of 51,457 adult surgical patients undergoing major inpatient surgery, long-term cardiovascular-specific mortality was modeled using a multivariable subdistributional hazards model while treating any other cause of death as a competing risk and accounting for the progression to end-stage renal disease (ESRD) after discharge. Pre-existing CKD and ESRD, and postoperative AKI were the main independent predictors.

RESULTS

Before the admission, 4% and 8% of the cohort had pre-existing ESRD and CKD not requiring renal replacement therapy, respectively. During hospitalization, 39% developed AKI. At 10-year follow-up, adjusted cardiovascular-specific mortality estimates were 6%, 11%, 12%, 19%, and 27% for patients with no kidney disease, AKI with no CKD, CKD with no AKI, AKI with CKD, and ESRD, respectively (P < 0.001). This association remained after excluding 916 patients who progressed to ESRD after discharge, although it was significantly amplified among them. Compared with patients having no kidney disease, adjusted hazard ratios for cardiovascular mortality were significantly higher among patients with kidney disease, ranging from 1.95 (95% confidence interval, 1.80-2.11) for patients with de novo AKI to 5.70 (95% confidence interval, 5.00-6.49) for patients with pre-existing ESRD.

CONCLUSIONS

Both AKI and CKD were associated with higher long-term cardiovascular-specific mortality compared with patients having no kidney disease.

Nuclear Magnetic Resonance Metabolomic Profiling of Mouse Kidney, Urine and Serum Following Renal Ischemia/Reperfusion Injury

Background

Ischemia/reperfusion (I/R) is the most common cause of acute kidney injury (AKI). Its pathophysiology remains unclear. Metabolomics is dedicated to identify metabolites involved in (patho)physiological changes of integrated living systems. Here, we performed ¹H-Nuclear Magnetic Resonance metabolomics using urine, serum and kidney samples from a mouse model of renal I/R.

Methods

Renal 30-min ischemia was induced in 12-week-old C57BL/6J male mice by bilaterally clamping vascular pedicles, and was followed by 6, 24 or 48-hour reperfusion (n = 12/group). Sham-operated mice were used as controls. Statistical discriminant analyses, i.e. principal component analysis and orthogonal projections to latent structures (OPLS-DA), were performed on urine, serum and kidney lysates at each time-point. Multivariate receiver operating characteristic (ROC) curves were drawn, and sensitivity and specificity were calculated from ROC confusion matrix (with averaged class probabilities across 100 cross-validations).

Results

Urine OPLS-DA analysis showed a net separation between I/R and sham groups, with significant variations in levels of taurine, di- and tri-methylamine, creatine and lactate. Such changes were observed as early as 6 hours post reperfusion. Major metabolome modifications occurred at 24h post reperfusion. At this time-point, correlation coefficients between urine spectra and conventional AKI biomarkers, i.e. serum creatinine and urea levels, reached 0.94 and 0.95, respectively. The area under ROC curve at 6h, 24h and 48h post surgery were 0.73, 0.98 and 0.97, respectively. Similar discriminations were found in kidney samples, with changes in levels of lactate, fatty acids, choline and taurine. By contrast, serum OPLS-DA analysis could not discriminate sham-operated from I/R-exposed animals.

Conclusions

Our study demonstrates that renal I/R in mouse causes early and sustained metabolomic changes in urine and kidney composition. The most implicated pathways at 6h and 24h post reperfusion include gluconeogenesis, taurine and hypotaurine metabolism, whereas protein biosynthesis, glycolysis, and galactose and arginine metabolism are key at 48h post reperfusion.

Relevance of New Definitions to Incidence and Prognosis of Acute Kidney Injury in Hospitalized Patients with Cirrhosis: A Retrospective Population-Based Cohort Study

BACKGROUND

The implementation of new serum creatinine (SCr)-based criteria for acute kidney injury (AKI) has brought to light several areas of uncertainty in patients with cirrhosis.

STUDY DESIGN

Population-based cohort study.

SETTING & PARTICIPANTS

Adults with cirrhosis hospitalized between 2002-2012.

PREDICTOR

We aimed to address the prognostic implications of the new AKI criteria in cirrhosis.

OUTCOMES

Baseline kidney function was defined from all outpatient SCr within 3 months before hospitalization. Cox proportional hazards models were fit to examine associations between AKI, renal recovery and all-cause mortality.

RESULTS

4,733 patients were studied. The 30-day mortality was higher for participants with AKI (43.9% vs 8.5%; p-value<0.001), and increased with AKI severity. The highest incidence of AKI occurred when the lowest SCr within the three months prior to admission was used to define baseline. The hazard ratio for mortality using the lowest SCr within 3 months and the closest pre-admission SCr (definition suggested by the recent consensus guideline) were similar, validating the use of the latter measure. As compared to patients without AKI, stage 1 AKI with maximum SCr ≤132 mmol/L remained associated with a 3.5-fold increased hazard of death at 30 days (95% CI 2.6 to 4.7).

LIMITATIONS

As an observational study, the results were vulnerable to residual confounding and ascertainment bias in the use of laboratory data to identify AKI. We did not have access to liver function or disease etiology variables and were unable to adjust for these in our analyses.

CONCLUSIONS

These results confirm the graded relationship between AKI severity, renal recovery, and mortality and further clarify previously discordant reports about the prognostic relevance of new AKI criteria in patients with cirrhosis.

Oliguria without serum creatinine increase after living donor liver transplantation is associated with adverse post-operative outcomes

BACKGROUND

Acute kidney injury (AKI) is a common complication after liver transplantation and is associated with significant morbidity and mortality. Although clinical guidelines recommend defining AKI based on serum creatinine increase and oliguria, the validity and utility of the oliguric component of AKI definition remains largely unexplored. This study examined the incidence and the impact on clinical outcomes of oliguria meeting the urine output criterion of AKI in patients undergoing liver transplantation. The authors hypothesised that oliguria was an independent risk factor for adverse post-operative outcomes.

METHODS

This study retrospectively examined 320 patients who underwent living donor liver transplantation at our centre. AKI stages were allocated according to recent guidelines based on serum creatinine or urine output within 7 days of surgery.

RESULTS

The incidence of oliguria meeting the urine output criterion of AKI was 50.3%. Compared with creatinine criterion alone, incorporating oliguria into the diagnostic criteria dramatically increased the measured incidence of AKI from 39.7% to 62.2%. Compared with patients diagnosed without AKI using either criterion, oliguric patients without serum creatinine increase had significantly longer intensive care unit stays (median: 5 vs. 4 days, P = 0.016), longer hospital stays (median: 60 vs. 49 days, P = 0.014) and lower chronic kidney disease-free survival rate on post-operative day 90 (54.2% vs. 73.3%, P = 0.008).

CONCLUSION

Oliguria is common after liver transplantation, and incorporating oliguria into the diagnostic criteria dramatically increases the measured incidence of AKI. Oliguria without serum creatinine increase was significantly associated with adverse post-operative outcomes.

Acute Kidney Injury After Major Surgery: A Retrospective Analysis of Veterans Health Administration Data

BACKGROUND

Few trials of acute kidney injury (AKI) prevention after surgery have been conducted, and most observational studies focus on AKI following cardiac surgery. The frequency of, risk factors for, and outcomes after AKI following other types of major surgery have not been well characterized and may present additional opportunities for trials in AKI.

STUDY DESIGN

Observational cohort study.

SETTING & PARTICIPANTS

3.6 million US veterans followed up from 2004 to 2011 for the receipt of major surgery (cardiac; general; ear, nose, and throat; thoracic; vascular; urologic; and orthopedic) and postoperative outcomes.

FACTORS

Demographics, health characteristics, and type of surgery.

OUTCOMES

Postoperative AKI defined by the KDIGO creatinine criteria, postoperative length of stay, end-stage renal disease, and mortality.

RESULTS

Postoperative AKI occurred in 11.8% of the 161,185 major surgery hospitalizations (stage 1, 76%; stage 2, 15%, stage 3 [without dialysis], 7%; and AKI requiring dialysis, 2%). Cardiac surgery had the highest postoperative AKI risk (relative risk [RR], 1.22; 95% CI, 1.17-1.27), followed by general (reference), thoracic (RR, 0.92; 95% CI, 0.87-0.98), orthopedic (RR, 0.70; 95% CI, 0.67-0.73), vascular (RR, 0.68; 95% CI, 0.64-0.71), urologic (RR, 0.65; 95% CI, 0.61-0.69), and ear, nose, and throat (RR, 0.32; 95% CI, 0.28-0.37) surgery. Risk factors for postoperative AKI included older age, African American race, hypertension, diabetes mellitus, and, for estimated glomerular filtration rate < 90mL/min/1.73m(2), lower estimated glomerular filtration rate. Participants with postoperative AKI had longer lengths of stay (15.8 vs 8.6 days) and higher rates of 30-day hospital readmission (21% vs 13%), 1-year end-stage renal disease (0.94% vs 0.05%), and mortality (19% vs 8%), with similar associations by type of surgery and more severe stage of AKI relating to poorer outcomes.

LIMITATIONS

Urine output was not available to classify AKI; cohort included mostly men.

CONCLUSIONS

AKI was common after major surgery, with similar risk factor and outcome associations across surgery type. These results can inform the design of clinical trials in postoperative AKI to the noncardiac surgery setting.

Acute kidney injury following hepatectomy for hepatocellular carcinoma: incidence, risk factors and prognostic value

BACKGROUND

Acute kidney injury (AKI) following hepatectomy remains understudied in terms of diagnosis, severity, recovery and prognostic value. The aim of this study was to assess the risk factors and prognostic value of AKI on short- and long-term outcomes following hepatectomy for hepatocellular carcinoma (HCC).

METHOD

This is a retrospective analysis of a single-center cohort of 457 consecutive patients who underwent hepatectomy for HCC. The KDIGO criteria were used for AKI diagnosis. The incidence, risk factors, and prognostic value of AKI were investigated.

RESULTS

AKI occurred in 67 patients (15%). The mortality and major morbidity rates were significantly higher in patients with AKI (37% and 69%) than in those without (6% and 22%; p < 0.001). Renal recovery was complete in 35 (52%), partial in 25 (37%), and absent in 7 (11%) patients. Advanced age, an increased MELD score, major hepatectomy and prolonged duration of operation were identified as independent predictors of AKI. AKI was identified as the strongest independent predictor of postoperative mortality but did not impact survival.

CONCLUSION

AKI is a common complication after hepatectomy for HCC. Although its development is associated with poor short-term outcomes, it does not appear to be predictive of impaired long-term survival.

Peri-operative renal dysfunction: prevention and management

Postoperative increases in serum creatinine concentration, by amounts historically viewed as trivial, are associated with increased morbidity and mortality. Acute kidney injury is common, affecting one in five patients admitted with acute medical disease and up to four in five patients admitted to intensive care, of whom one in two have had operations. This review is focused principally on the identification of patients at risk of acute kidney injury and the prevention of injury. In the main, there are no interventions that directly treat the damaged kidney. The management of acute kidney injury is based on correction of dehydration, hypotension, and urinary tract obstruction, stopping nephrotoxic drugs, giving antibiotics for bacterial infection, and commencing renal replacement therapy if necessary.

Candidate Surrogate End Points for ESRD after AKI

AKI, a frequently transient condition, is not accepted by the US Food and Drug Association as an end point for drug registration trials. We assessed whether an intermediate-term change in eGFR after AKI has a sufficiently strong relationship with subsequent ESRD to serve as an alternative end point in trials of AKI prevention and/or treatment. Among 161,185 United States veterans undergoing major surgery between 2004 and 2011, we characterized in-hospital AKI by Kidney Disease Improving Global Outcomes creatinine criteria and decline in eGFR from prehospitalization to postdischarge time points and quantified associations of these values with ESRD and mortality over a median of 3.8 years. An eGFR decline of ≥30% at 30, 60, and 90 days after discharge occurred in 3.1%, 2.5%, and 2.6%, of survivors without AKI and 15.9%, 12.2%, and 11.7%, of survivors with AKI. For patients with in-hospital AKI compared with those with no AKI and stable eGFR, a 30% decline in eGFR at 30, 60, and 90 days after discharge demonstrated adjusted hazard ratios (95% confidence intervals) of ESRD of 5.60 (4.06 to 7.71), 6.42 (4.76 to 8.65), and 7.27 (5.14 to 10.27), with corresponding estimates for 40% decline in eGFR of 6.98 (5.21 to 9.35), 8.03 (6.11 to 10.56), and 10.95 (8.10 to 14.82). Risks for mortality were smaller but consistent in direction. A 30%-40% decline in eGFR after AKI could be a surrogate end point for ESRD in trials of AKI prevention and/or treatment, but additional trial evidence is needed.

Assessment of Renal Hemodynamics and Oxygenation by Simultaneous Magnetic Resonance Imaging (MRI) and Quantitative Invasive Physiological Measurements

In vivo assessment of renal perfusion and oxygenation under (patho)physiological conditions by means of noninvasive diagnostic imaging is conceptually appealing. Blood oxygen level-dependent (BOLD) magnetic resonance imaging (MRI) and quantitative parametric mapping of the magnetic resonance (MR) relaxation times T 2* and T 2 are thought to provide surrogates of renal tissue oxygenation. The validity and efficacy of this technique for quantitative characterization of local tissue oxygenation and its changes under different functional conditions have not been systematically examined yet and remain to be established. For this purpose, the development of an integrative multimodality approaches is essential. Here we describe an integrated hybrid approach (MR-PHYSIOL) that combines established quantitative physiological measurements with T 2* (T 2) mapping and MR-based kidney size measurements. Standardized reversible (patho)physiologically relevant interventions, such as brief periods of aortic occlusion, hypoxia, and hyperoxia, are used for detailing the relation between the MR-PHYSIOL parameters, in particular between renal T 2* and tissue oxygenation.

Association of Pre-Operative Albuminuria with Post-Operative Outcomes after Coronary Artery Bypass Grafting

The effect on post-operative outcomes after coronary artery bypass graft(CABG) surgery is not clear. Among 17,812 patients who underwent CABG during October 1,2006-September 28,2012 in any Department of US Veterans Affairs(VA) hospital, we identified 5,968 with available preoperative urine albumin-creatinine ratio(UACR) measurements. We examined the association of UACR<30, 30–299 and >=300 mg/g with 30/90/180/365-day and overall all-cause mortality, and hospitalization length >10 days, and with acute kidney injury(AKI). Mean ± SD baseline age and eGFR were 66 ± 8 years and 77 ± 19 ml/min/1.73 m², respectively. 788 patients(13.2%) died during a median follow-up of 3.2 years, and 26.8% patients developed AKI(23.1%-Stage 1; 2.9%-Stage 2; 0.8%-Stage 3) within 30 days of CABG. The median lengths of stay were 8 days(IQR: 6–13 days), 10 days(IQR: 7–14 days) and 12 days(IQR: 8–19 days) for groups with UACR < 30 mg/g, 30–299 mg/g and ≥300 mg/g, respectively. Higher UACR conferred 72 to 85% higher 90-, 180-, and 365-day mortality compared to UACR<30 mg/g (odds ratio and 95% confidence interval for UACR≥300 vs. <30 mg/g: 1.72(1.01–2.95); 1.85(1.14–3.01); 1.74(1.15–2.61), respectively). Higher UACR was also associated with significantly longer hospitalizations and higher incidence of all stages of AKI. Higher UACR is associated with significantly higher odds of mortality, longer post-CABG hospitalization, and higher AKI incidence.

Single high dose gentamicin for perioperative prophylaxis in orthopedic surgery: Evaluation of nephrotoxicity

Background:

Recent studies described an increase in acute kidney injury when high dose gentamicin was included in perioperative prophylaxis for orthopedic surgeries. To this effect, we compared the rate of nephrotoxicity for selected orthopedic surgeries where gentamicin was included (Gentamicin Group) to those where it was not included (Control Group) for perioperative prophylaxis and evaluated risk factors for nephrotoxicity.

Methods:

Spine, hip and knee surgeries performed between April 2011 and December 2013 were reviewed retrospectively. Gentamicin was given to eligible patients based on age, weight and Creatinine Clearance. Nephrotoxicity was assessed using Risk, Injury, Failure, Loss, End-stage kidney disease (RIFLE) criteria.

Results:

Among selected surgeries (N = 1590 in Gentamicin Group: hip = 926, spine = 600, knee = 64; N = 2587 in Control Group: hip = 980, spine = 902, knee = 705), patients’ body weight, serum creatinine, comorbidities and surgery duration were similar in Gentamicin Group and Control Group. Gentamicin median dose was 4.5 mg/kg of dosing weight. Nephrotoxicity rate was 2.5% in Gentamicin Group and 1.8% in Control Group, p = 0.17. Most cases of nephrotoxicity were Risk category by RIFLE criteria (67% in Gentamicin Group and 72% in Control Group, p = 0.49). In logistic regression, risk factors for nephrotoxicity were hospital stay >1 day prior to surgery (odds ratio = 8.1; 95% confidence interval = 2.25–28.97, p = 0.001), knee or hip surgery (odds ratio = 4.7; 95% confidence interval = 2.9–9.48, p = 0.0005) and diabetes (odds ratio = 1.95; 95% confidence interval = 1.13–3.35, p = 0.016). Receipt of gentamicin was not an independent predictor of nephrotoxicity (odds ratio = 1.5; 95% confidence interval = 0.97–2.35, p = 0.07).

Conclusion:

In this cohort, rate of nephrotoxicity was similar between Gentamicin Group and Control Group. Single high dose gentamicin is a safe and acceptable option for perioperative prophylaxis in eligible patients undergoing orthopedic surgeries.

Acute Kidney Injury in the Surgical Patient

Perioperative acute kidney injury (AKI) is a common, morbid, and costly surgical complication. Current efforts to understand and manage AKI in surgical patients focus on prevention, mitigation of further injury when AKI has occurred, treatment of associated conditions, and facilitation of renal recovery. Lesser severity AKI is now understood to be much more common, and more morbid, than was previously thought. The ability to detect AKI within hours of onset would be helpful in protecting the kidney and in preserving renal function, and several imaging and biomarker modalities are currently being evaluated.

Acute Kidney Injury in the Surgical Patient: Recognition and Attribution

Postoperative acute kidney injury (AKI) is not only one of the most common postoperative complications but is also associated with increased in-hospital mortality, decreased survival for up to 10 years after surgery and an increased risk for progression to chronic kidney disease and hemodialysis. Most of the studies that have developed clinically applicable risk models for prediction of AKI have focused on the most severe stages of AKI and rarely on less severe stages defined by consensus definitions. Furthermore, although multiple physiological signals are continuously recorded as a part of intraoperative management, their use for the development of risk models for AKI has been limited. Accurate risk stratification of patients in real time would enable the selection of optimal therapy in a timely fashion to prevent AKI altogether, or to mitigate the effects of the complication even before symptoms arise and can be tailored to a patients' personal clinical profile.