Acute kidney injury in major gynaecological surgery: an observational study

Candidate Kidney Protective Strategies for Patients Undergoing Major Abdominal Surgery: A Secondary Analysis of the RELIEF Trial Cohort

BACKGROUND

Acute kidney injury (AKI) is common after major abdominal surgery. Selection of candidate kidney protective strategies for testing in large trials should be based on robust preliminary evidence.

METHODS

A secondary analysis of the Restrictive versus Liberal Fluid Therapy in Major Abdominal Surgery (RELIEF) trial was conducted in adult patients undergoing major abdominal surgery and randomly assigned to a restrictive or liberal perioperative fluid regimen. The primary outcome was maximum AKI stage before hospital discharge. Two multivariable ordinal regression models were developed to test the primary hypothesis that modifiable risk factors associated with increased maximum stage of postoperative AKI could be identified. Each model used a separate approach to variable selection to assess the sensitivity of the findings to modeling approach. For model 1, variable selection was informed by investigator opinion; for model 2, the Least Absolute Shrinkage and Selection Operator (LASSO) technique was used to develop a data-driven model from available variables.

RESULTS

Of 2,444 patients analyzed, stage 1, 2, and 3 AKI occurred in 223 (9.1%), 59 (2.4%), and 36 (1.5%) patients, respectively. In multivariable modeling by model 1, administration of a nonsteroidal anti-inflammatory drug or cyclooxygenase-2 inhibitor, intraoperatively only (odds ratio, 1.77 [99% CI, 1.11 to 2.82]), and preoperative day-of-surgery administration of an angiotensin-converting enzyme inhibitor or angiotensin receptor blocker compared to no regular use (odds ratio, 1.84 [99% CI, 1.15 to 2.94]) were associated with increased odds for greater maximum stage AKI. These results were unchanged in model 2, with the additional finding of an inverse association between nadir hemoglobin concentration on postoperative day 1 and greater maximum stage AKI.

CONCLUSIONS

Avoiding intraoperative nonsteroidal anti-inflammatory drugs or cyclooxygenase-2 inhibitors is a potential strategy to mitigate the risk for postoperative AKI. The findings strengthen the rationale for a clinical trial comprehensively testing the risk-benefit ratio of these drugs in the perioperative period.

EDITOR’S PERSPECTIVE

The clinical utility of routine postoperative hemoglobin and creatinine after reconstructive surgery for apical pelvic organ prolapse

INTRODUCTION AND HYPOTHESIS

Postoperative laboratory tests are routinely ordered after apical prolapse repair on asymptomatic patients. We hypothesize that routine serum hemoglobin (Hb) and creatinine (Cr) have limited clinical utility in the postoperative period in asymptomatic patients.

METHODS

This is a retrospective cohort study of patients who underwent surgical repair of apical prolapse between 2017 and 2019 at our institution. Subjects were divided into two groups postoperatively: symptomatic and asymptomatic anemia. Symptomatic patients were defined as having one or more of the following: blood pressure (BP) <90/60, heart rate (HR) >100, urine output <30 cc/h, subjective dizziness, flank pain, or abdominal pain. The primary aim was to evaluate the utility of postoperative serum Hb and Cr in symptomatic and asymptomatic patients. Fisher's exact and Mann-Whitney tests analyzed categorical and continuous data respectively. A total of 325 patients were included.

RESULTS

Patients with symptomatic anemia had a larger decrease in Hb on postoperative day 1 (POD1) with a mean decrease of -18.11% (± 6.64) compared with asymptomatic patients, who had a mean difference of -15.49% (± 5.63; p < 0.001). The total cost of tests evaluating Hb was US$61,745. Patients with symptomatic acute kidney injury had an increase in Cr on POD1 compared with asymptomatic patients, with a mean increase of 0.23% (± 16.06) and -3.07% (± 13.10) respectively (p < 0.05). The total cost of tests including Cr was US$131,812.

CONCLUSIONS

Our results indicate that routine postoperative Hb and Cr testing for apical prolapse should be reserved for symptomatic patients as it has minimal clinical value in asymptomatic patients and contributes to increased overall health care cost.

Olaparib in an ovarian cancer patient with end-stage renal disease and hemodialysis

PURPOSE

For patients with severe renal impairment (CrCl ≤ 30 ml/min) or end-stage renal disease (ESRD), olaparib intake is not recommended as the pharmacokinetics and safety of olaparib have not been evaluated in this patient group. Therefore, this valuable patient group is generally excluded from poly(ADP-ribose) polymerase inhibitor (PARPi) therapy. Here we report the pharmacokinetics (PK), efficacy, safety and tolerability of olaparib capsules 200 mg BID in a patient with recurrent epithelial ovarian cancer (EOC) and ESRD requiring hemodialysis.

METHODS

Blood and dialysate samples of the patient were collected on a dialysis and non-dialysis day. Olaparib total plasma concentrations were determined through high-performance liquid chromatography with tandem mass spectrometric detection. Actual scheduled sample times were used in the PK analysis to determine multiple dose PK parameters at steady state.

RESULTS

Maximum concentration was achieved 1.5 h after drug administration on non- dialysis and after 1 h on dialysis day. The steady-state trough concentration and the maximal plasma concentration were similar on dialysis and non- dialysis day. On non-dialysis day, the AUC_ss was 30% higher (24.0 µg.h/mL vs. 16.9 µg.h/ml) than on dialysis day. The plasma clearance CL_ss/F was lower on non-dialysis day. Olaparib was not detectable in the dialysate samples.

CONCLUSION

A total dose of olaparib 200 mg BID capsule formulation was well tolerated by our patient with ESRD and hemodialysis. Moreover, this maintenance therapy led to 16 months of progression free survival. Further trials on PARPi therapy in patients with hemodialysis are warranted.

Postoperative Acute Kidney Injury by Age and Sex: A Retrospective Cohort Association Study

BACKGROUND

Acute kidney injury (AKI) after noncardiac surgery is common and has substantial health impact. Preclinical and clinical studies examining the influence of sex on AKI have yielded conflicting results, although they typically do not account for age-related changes. The objective of the study was to determine the association of age and sex groups on postoperative AKI. The authors hypothesized that younger females would display lower risk of postoperative AKI than males of similar age, and the protection would be lost in older females.

METHODS

This was a multicenter retrospective cohort study across 46 institutions between 2013 and 2019. Participants included adult inpatients without pre-existing end-stage kidney disease undergoing index major noncardiac, nonkidney/urologic surgeries. The authors' primary exposure was age and sex groups defined as females 50 yr or younger, females older than 50 yr, males 50 yr or younger, and males older than 50 yr. The authors' primary outcome was development of AKI by Kidney Disease-Improving Global Outcomes serum creatinine criteria. Exploratory analyses included associations of ascending age groups and hormone replacement therapy home medications with postoperative AKI.

RESULTS

Among 390,382 patients, 25,809 (6.6%) developed postoperative AKI (females 50 yr or younger: 2,190 of 58,585 [3.7%]; females older than 50 yr: 9,320 of 14,4047 [6.5%]; males 50 yr or younger: 3,289 of 55,503 [5.9%]; males older than 50 yr: 11,010 of 132,447 [8.3%]). When adjusted for AKI risk factors, compared to females younger than 50 yr (odds ratio, 1), the odds of AKI were higher in females older than 50 yr (odds ratio, 1.51; 95% CI, 1.43 to 1.59), males younger than 50 yr (odds ratio, 1.90; 95% CI, 1.79 to 2.01), and males older than 50 yr (odds ratio, 2.06; 95% CI, 1.96 to 2.17).

CONCLUSIONS

Younger females display a lower odds of postoperative AKI that gradually increases with age. These results suggest that age-related changes in women should be further studied as modifiers of postoperative AKI risk after noncardiac surgery.

EDITOR’S PERSPECTIVE

Association between postoperative acute kidney injury and mortality after plastic and reconstructive surgery

Acute kidney injury (AKI) is a common postoperative disorder that is associated with considerable morbidity and mortality. Although the role of AKI as an independent risk factor for mortality has been well characterized in major surgeries, its effect on postoperative outcomes in plastic and reconstructive surgery has not been evaluated. This study explored the association between postoperative AKI and mortality in patients undergoing plastic and reconstructive surgery. Consecutive adult patients who underwent plastic and reconstructive surgery without end-stage renal disease (n = 7059) at our institution from January 2011 to July 2019 were identified. The patients were divided into two groups according to occurrence of postoperative AKI: 7000 patients (99.2%) in the no AKI group and 59 patients (0.8%) in the AKI group. The primary outcome was mortality during the first year, and overall mortality and 30-days mortality were also compared. After inverse probability weighting, mortality during the first year after plastic and reconstructive surgery was significantly increased in the AKI group (1.9% vs. 18.6%; hazard ratio, 6.69; 95% confidence interval, 2.65-16.85; p < 0.001). In this study, overall and 30-day mortalities were shown to be higher in the AKI group, and further studies are needed on postoperative AKI in plastic and reconstructive surgery.

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.

Risk factors for acute kidney injury after major abdominal surgery in the elderly aged 75 years and above

OBJECTIVES

The study aimed to investigate the incidence and risk factors of acute kidney injury (AKI) in elderly patients (aged ≥ 75 years) undergoing major nonvascular abdominal surgery.

METHODS

The study was a retrospective study that evaluated the incidence of AKI in patients within 48 h after major abdominal surgeries. Patients' preoperative characteristics and intraoperative management, including the use of nephrotoxic medications, were evaluated for associations with AKI using a logistic regression model.

RESULTS

A total of 573 patients were included in our analysis. A total of 33 patients (5.76%) developed AKI, and 30 (90.91%), 2 (6.06%) and 1 (3.03%) reached the AKI stages 1, 2 and 3, respectively. Older age (adjusted OR, aOR 1.112, 95% confidence interval, CI 1.020-1.212), serum albumin (aOR 0.900, 95% CI 0.829-0.977), baseline eGFR (aOR 3.401, 95% CI 1.479-7.820), the intraoperative occurrence of hypotension (aOR 3.509, 95% CI 1.553-7.929), and the use of hydroxyethyl starch in combination with nonsteroidal anti-inflammatory drugs (aOR 3.596, 95% CI 1.559-8.292) or furosemide (aOR 5.724, 95% CI 1.476-22.199) were independent risk factors for postoperative AKI.

CONCLUSIONS

Several risk factors, including intraoperative combined administration of HES and furosemide, are independent factors for AKI during abdominal surgeries. Anesthesiologists and surgeons should take precautions in treating at-risk patients.

Oncosurgery-Related Acute Kidney Injury

Oncosurgery is a surgical specialty that focuses on the diagnosis, staging, and management of cancer and cancer-related complications. Acute kidney injury is a common and important complication related to oncologic surgery, associated with longer hospital length of stay, greater costs, increased risk of incident or progressive chronic kidney disease (CKD), and higher mortality. The pathogenesis of oncosurgery-related acute kidney injury is multifactorial and determined by different variables, including patient characteristics (comorbidities, volume status, age, pre-existing CKD), specific cancer type or location, surgical procedure involved, as well as intrinsic neuroendocrine and hemodynamic responses to anesthesia and/or surgery. Early nephrology evaluation may be helpful to assist with preservation of kidney function and prevention of further kidney injury.

Incidence of acute kidney injury after open gynecologic surgery in an enhanced recovery after surgery pathway

OBJECTIVE

To determine the incidence of postoperative AKI after open gynecologic surgery within ERAS, compare AKI in pre-ERAS and ERAS cohorts, and identify factors associated with AKI.

METHODS

We compared postoperative AKI in patients who underwent open gynecologic surgery at one institution before and after ERAS implementation. AKI was defined as acute risk, injury, or failure by RIFLE criteria. Pre-ERAS and ERAS cohorts were matched using propensity score analysis in a 1:1 fashion using the nearest neighbor technique. Chi-squared, Fisher's Exact, and Wilcoxon rank-sum tests were used.

RESULTS

Among 1334 ERAS and 191 pre-ERAS patients, postoperative AKI incidence was higher in the ERAS cohort (13.1% vs 5.8%, p = .004). In 166 matched pairs, ERAS patients had higher incidence (16.9% vs 5.4%, p < .001) and odds (OR 3.54, 95% CI 1.61-7.76) of AKI. Within ERAS, AKI was associated with older age (median age 65 vs 57, p < .001), Charlson Comorbidity Index score ≥ 3 (71.4% vs 57.9%, p < .001), and higher intraoperative estimated blood loss (400 vs 225 mL, p < .001), fluid administration (net fluid balance +1535 vs 1261 mL, p < .001), and hypotension lasting >5 min (41.7% vs 30.7%, p < .001). ERAS patients with AKI had longer hospital stays (median 4 vs 3 days, p < .001) and more readmissions (19% vs. 10%, p < .001) and grade 3+ complications (26% vs. 7%, p < .001).

CONCLUSIONS

The incidence and odds of postoperative AKI was higher after gynecologic surgery within ERAS, and patients with AKI were more likely to have complications. Potential strategies to prevent postoperative AKI include perioperative fluid and blood pressure optimization.

Rhabdomyolysis After Total Abdominal Hysterectomy Requiring Urgent Hemodialysis Due to Hyperkalemia

A 63-year-old woman with a past medical history of invasive ductal carcinoma of the breast, status post lumpectomy and chemoradiation, 15 cm left inguinal-femoral enlarged lymph node consistent with high-grade serous carcinoma of the ovary and 4.7 cm right adnexal mass underwent total abdominal hysterectomy, bilateral salpingo-oophorectomy, omentectomy, and lymph node dissection with cystoscopy and bilateral ureteral catheter placement. There was no intraoperative complication. After surgery, patient’s urine output decreased, and she developed acute kidney injury (AKI). Initially, it was thought that her reduced output might be due to surgery/anesthesia. She also developed arm and leg weakness raising suspicion for stroke. The neurological workup was unremarkable for any acute abnormality. Her creatinine kinase (CK) level was >20,000 u/l consistent with rhabdomyolysis. She was hydrated aggressively and required hemodialysis due to hyperkalemia. During the hospital course, her kidney function improved, and rhabdomyolysis resolved, and she did not require dialysis after discharge.

Strategies to Reduce Perioperative Nephrotoxicity

Postoperative acute kidney injury (AKI) is a common complication of surgery that is associated with significant adverse outcomes, including increased morbidity and mortality. The perioperative burden of AKI risk factors is complex and potentially large, including high-risk nephrotoxic medications, hypotension, hypovolemia, radiologic contrast, anemia, and surgery-specific factors. Understanding the pathogenesis, risk factors, and potential cumulative impact of perioperative nephrotoxic exposures is particularly important in the prevention and reduction of perioperative AKI. This review outlines the possible strategies to reduce perioperative nephrotoxicity and the development of postoperative AKI.

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.

Management of post-operative acute kidney injury

Post-operative acute kidney injury (AKI) is a common complication of surgery with significant short- and long-term adverse consequences. The adoption of diagnostic criteria for AKI (RIFLE, AKIN and KDIGO) has facilitated comparison of data reported by different centres, confirming that even mild AKI is associated with excess mortality. It remains unclear whether this is caused by the kidney injury itself or whether AKI is simply a marker of underlying disease severity. There is no trial evidence to support the use of any specific therapeutic intervention in post-operative AKI. Best current treatment is, therefore, preventative by optimizing hydration and avoidance of nephrotoxins, emphasizing the importance of earlier detection and identification of individuals at high risk for AKI. In this review, we examine the latest literature on the management of post-operative AKI in adult patients, specifically the diagnosis and definition of AKI, epidemiology and pathogenesis and risk stratification in cardiac and non-cardiac surgery. We also review the latest evidence on pharmacological and non-pharmacological interventions.

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.

Preoperative assessment of the risk for multiple complications after surgery

BACKGROUND

The association between preoperative patient characteristics and the number of major postoperative complications after a major operation is not well defined.

METHODS

In a retrospective, single-center cohort of 50,314 adult surgical patients, we used readily available preoperative clinical data to model the number of major postoperative complications from none to ≥3. We included acute kidney injury; prolonged stay (>48 hours) in an intensive care unit; need for prolonged (>48 hours) mechanical ventilation; severe sepsis; and cardiovascular, wound, and neurologic complications. Risk probability scores generated from the multinomial logistic models were used to develop an online calculator. We stratified patients based on their risk of having ≥3 postoperative complications.

RESULTS

Patients older than 65 years (odds ratio 1.5, 95% confidence interval, 1.4-1.6), males (odds ratio 1.2, 95% confidence interval, 1.2-1.3), patients with a greater Charlson comorbidity index (odds ratio 3.9, 95% confidence interval, 3.6-4.2), patients requiring emergency operation (odds ratio 3.5, 95% confidence interval, 3.3.-3.7), and patients admitted on a weekend (odds ratio 1.4, 95% confidence interval, 1.3-1.5) were more likely to have ≥3 postoperative complications than they were to have none. Patients in the medium- and high-risk categories were 3.7 and 6.3 times more likely to have ≥3 postoperative complications, respectively. High-risk patients were 5.8 and 4.4 times more likely to die within 30 and 90 days of admission, respectively.

CONCLUSION

Readily available, preoperative clinical and sociodemographic factors are associated with a greater number of postoperative complications and adverse surgical outcomes. We developed an online calculator that predicts probability of developing each number of complications after a major operation.

Identification of Risk Factors Associated With Postoperative Acute Kidney Injury After Esophagectomy for Esophageal Cancer

OBJECTIVE

To identify risks factors associated with acute kidney injury (AKI) after esophageal cancer surgery.

DESIGN

This was a retrospective study.

SETTING

Single academic center.

PARTICIPANTS

Subjects with non-metastatic esophageal cancer. Patients were excluded if they were younger than 18 years and had missing data.

MEASUREMENTS AND MAIN RESULTS

Primary outcome of the study was AKI according to AKI Network criteria. Demographic and perioperative variables were compared in patients with and without AKI. A multivariate Cox proportional model was used to assess the association between perioperative variables and AKI; p<0.05 was considered statistically significant. AKI was found in 107 (11.9%) of the 898 patients included in the study. The multivariate analysis also showed that BMI (odds ratio [OR] 1.07, 95% confidence interval [CI] 1.03-1.11), number of comorbidities (OR 1.52, 95% CI 1.20-1.93, p = 0.001), and preoperative creatinine concentrations (OR 2.37, 95% CI 1.14-4.92, p = 0.02) were independent predictors for AKI. The use of dexamethasone was associated with a reduced risk for AKI.

CONCLUSIONS

In support of previous reports in the literature, the authors found that AKI was not an uncommon complication after esophageal surgery. Obesity, cardiovascular comorbidities, and high preoperative concentrations were predictors of AKI. Dexamethasone administration during surgery appeared to have a protective effect. This finding opens an opportunity to further study in a randomized controlled trial the efficacy of dexamethasone in the prevention of AKI.

Establishing a continuum of acute kidney injury - tracing AKI using data source linkage and long-term follow-up: Workgroup Statements from the 15th ADQI Consensus Conference

Background

Acute kidney injury (AKI) is independently associated with the development of chronic kidney disease, endstage kidney disease and increased all-cause and cardiovascular-specific mortality. The severity of the renal insult and the development of multiple AKI episodes increase the risk of occurrence of these outcomes. Despite these long-term effects, only a minority of patients receive nephrologist follow up after an episode of AKI; those that do may have improved outcomes. Furthermore, relatively simple quality improvement strategies have the potential to change this status quo.

Methods

On this background, a working group of the 15^th Acute Dialysis Quality Initiative (ADQI) conference applied the consensus-building process informed by review of English language articles identified through PubMed search to address questions related to the opportunities, methodological requirements and barriers for longitudinal follow-up of patients with AKI in the era of electronic health records and Big Data.

Results

Four consensus statements answering the key questions identified by the working group are developed.

Conclusions

We have identified minimal data elements and potential data sources necessary to trace the natural history of patients from onset of AKI to long-term outcome. Minimum infrastructure and key barriers to achieving these goals are outlined together with proposed solutions.

Acute kidney injury, long-term renal function and mortality in patients undergoing major abdominal surgery: a cohort analysis

Background

Acute kidney injury (AKI) is frequent during hospitalization and may contribute to adverse consequences. We aimed to evaluate long-term adverse renal function and mortality after postoperative AKI in a cohort of patients undergoing major abdominal surgery.

Methods

We performed a retrospective analysis of adult patients who underwent major non-vascular abdominal surgery between January 2010 and February 2011 at the Department of Surgery II of Hospital de Santa Maria–Centro Hospitalar Lisboa Norte, Portugal. Exclusion criteria were as follows: chronic kidney disease on renal replacement therapy, undergoing renal replacement therapy the week before surgery, death before discharge and loss to follow-up through January 2014. Patients were categorized according to the development of postoperative AKI in the first 48 h after surgery using the Kidney Disease: Improving Global Outcomes classification. AKI was defined by an increase in absolute serum creatinine (SCr) ≥0.3 mg/dL or by a percentage increase in SCr ≥50% and/or by a decrease in urine output to <0.5 mL/kg/h for >6 h. Adverse renal outcomes (need for long-term dialysis and/or a 25% decrease in estimated glomerular filtration rate after hospital discharge) and mortality after discharge were evaluated. Cumulative mortality was analysed with the Kaplan–Meier method and log-rank test and outcome predictive factors with the Cox regression. Significance was set at P < 0.05.

Results

Of 390 selected patients, 72 (18.5%) developed postoperative AKI. The median follow-up was 38 months. Adverse renal outcomes and death after hospital discharge were more frequent among AKI patients (47.2 versus 22.0%, P < 0.0001; and 47.2 versus 20.5%, P < 0.0001, respectively). The 4 year cumulative probability of death was 44.4% for AKI patients, while it was 19.8% for patients with no AKI (log-rank test, P < 0.0001). In multivariate analysis, AKI was a risk factor for adverse renal outcomes (adjusted hazard ratio 1.6, P = 0.046) and mortality (adjusted hazard ratio 1.4, P = 0.043).

Conclusions

AKI after major abdominal surgery was independently associated with the risk of long-term need for dialysis and/or renal function decline and with the risk of death after hospital discharge.

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.

Mortality and Cost of Acute and Chronic Kidney Disease after Vascular Surgery

BACKGROUND

Both acute kidney injury (AKI) and chronic kidney disease (CKD) are common yet underappreciated risk factors for adverse perioperative outcomes. We hypothesize that AKI and CKD are associated with similar increases in 90-day mortality and cost in patients undergoing major vascular surgery.

METHODS

We used multivariable regression analyses to evaluate the associations between AKI and CKD and incremental 90-day mortality and hospital cost in a single-center cohort of 3646 adult patients undergoing major vascular surgery. We defined AKI using Kidney Disease: Improving Global Outcomes criteria as change in creatinine ≥ 0.3 mg/dL or ≥ 50% increase from the reference value. CKD was determined from medical history. Regression models were adjusted for demographic and socioeconomic characteristics, comorbid conditions, surgery type, and postoperative complications.

RESULTS

The prevalence of kidney disease among vascular surgery patients is high with 49% of patients developing AKI during hospitalization and 17% presenting with CKD on admission. In risk-adjusted logistic regression analysis, perioperative AKI (odds ratio 2.2, 95% confidence interval 1.5-3.3) was the most significant predictor of 90-day mortality. The risk-adjusted average cost was significantly higher for patients with any type of kidney disease. The incremental cost of having any type of kidney disease ranged from $9100 to $19,100, even after adjustment for underlying comorbidities and other postoperative complications.

CONCLUSIONS

Kidney disease after major vascular surgery is associated with significant increases in 90-day mortality and cost with the highest risk observed among patients with AKI regardless of previous CKD.