Development and Validation of a Prediction Score for Postoperative Acute Renal Failure Following Liver Resection

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

BACKGROUND

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

METHODS

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

RESULTS

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

CONCLUSIONS

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

Major liver resections, perioperative issues and posthepatectomy liver failure: A comprehensive update for the anesthesiologist

Significant advances in surgical techniques and relevant medium- and long-term outcomes over the past two decades have led to a substantial expansion in the indications for major liver resections. To support these outstanding results and to reduce perioperative complications, anesthesiologists must address and master key perioperative issues (preoperative assessment, proactive intraoperative anesthesia strategies, and implementation of the Enhanced Recovery After Surgery approach). Intensive care unit monitoring immediately following liver surgery remains a subject of active and often unresolved debate. Among postoperative complications, posthepatectomy liver failure (PHLF) occurs in different grades of severity (A-C) and frequency (9%-30%), and it is the main cause of 90-d postoperative mortality. PHLF, recently redefined with pragmatic clinical criteria and perioperative scores, can be predicted, prevented, or anticipated. This review highlights: (1) The systemic consequences of surgical manipulations anesthesiologists must respond to or prevent, to positively impact PHLF (a proactive approach); and (2) the maximal intensive treatment of PHLF, including artificial options, mainly based, so far, on Acute Liver Failure treatment(s), to buy time waiting for the recovery of the native liver or, when appropriate and in very selected cases, toward liver transplant. Such a clinical context requires a strong commitment to surgeons, anesthesiologists, and intensivists to work together, for a fruitful collaboration in a mandatory clinical continuum.

A nomogram for predicting acute kidney injury following hepatectomy: A propensity score matching analysis

STUDY OBJECTIVE

The low central venous pressure (LCVP) technique is a key technique in hepatectomy, but its impact on acute kidney injury (AKI) is unclear. The purpose of this study was to explore risk factors (in particular LCVP time) for AKI following hepatectomy.

DESIGN

A retrospective case-control study with propensity score matching.

SETTING

Operating room.

PATIENTS

A total of 1949 patients who underwent hepatectomy were studied.

INTERVENTIONS

The patients were grouped with or without AKI within 7 days after surgery. Univariable and multivariable analyses were performed, including recognized intraoperative predictors. The final result is represented as a nomogram.

MEASUREMENTS

Preoperative, intraoperative and postoperative data were collected. LCVP is monitored directly through a central venous catheter via the right internal jugular vein.

MAIN RESULTS

AKI occurred in 148 patients (7.59%). Surgery time, minimum SBP, furosemide administration and norepinephrine were identified as independent risk factors. The area under the curve for the receiver operating characteristic curves was 0.726 (95% CI 0.668-0.783).

CONCLUSION

Intraoperative parameters can be used to predict the probability of postoperative AKI. Although AKI increases the length of stay, it may not increase in-hospital mortality. LCVP time was not confirmed to be a risk factor for AKI.

Characterization of Risk Prediction Models for Acute Kidney Injury: A Systematic Review and Meta-analysis

Importance

Despite the expansion of published prediction models for acute kidney injury (AKI), there is little evidence of uptake of these models beyond their local derivation nor data on their association with patient outcomes.

Objective

To systematically review published AKI prediction models across all clinical subsettings.

Data Sources

MEDLINE via PubMed (January 1946 to April 2021) and Embase (January 1947 to April 2021) were searched using medical subject headings and text words related to AKI and prediction models.

Study Selection

All studies that developed a prediction model for AKI, defined as a statistical model with at least 2 predictive variables to estimate future occurrence of AKI, were eligible for inclusion. There was no limitation on study populations or methodological designs.

Data Extraction and Synthesis

Two authors independently searched the literature, screened the studies, and extracted and analyzed the data following the Preferred Reporting Items for Systematic Review and Meta-analyses guideline. The data were pooled using a random-effects model, with subgroups defined by 4 clinical settings. Between-study heterogeneity was explored using multiple methods, and funnel plot analysis was used to identify publication bias.

Main Outcomes and Measures

C statistic was used to measure the discrimination of prediction models.

Results

Of the 6955 studies initially identified through literature searching, 150 studies, with 14.4 million participants, met the inclusion criteria. The study characteristics differed widely in design, population, AKI definition, and model performance assessments. The overall pooled C statistic was 0.80 (95% CI, 0.79-0.81), with pooled C statistics in different clinical subsettings ranging from 0.78 (95% CI, 0.75-0.80) to 0.82 (95% CI, 0.78-0.86). Between-study heterogeneity was high overall and in the different clinical settings (eg, contrast medium-associated AKI: I2 = 99.9%; P < .001), and multiple methods did not identify any clear sources. A high proportion of models had a high risk of bias (126 [84.4%]) according to the Prediction Model Risk Of Bias Assessment Tool.

Conclusions and Relevance

In this study, the discrimination of the published AKI prediction models was good, reflected by high C statistics; however, the wide variation in the clinical settings, populations, and predictive variables likely drives the highly heterogenous findings that limit clinical utility. Standardized procedures for development and validation of prediction models are urgently needed.

Challenging cases in high-risk prostate cancer patients treated with Retzius-sparing robot-assisted radical prostatectomy

OBJECTIVE

To evaluate the relationship between enlarged prostate, bulky median lobe (BML) or prior benign prostatic hyperplasia (BPH) surgery and perioperative functional, and oncological outcomes in high-risk (HR) prostate cancer (PCa) patients treated with Retzius-sparing robot-assisted radical prostatectomy (RS-RARP).

METHODS

320 HR-PCa patients treated with RS-RARP between 2011 and 2020 at a single high-volume center. The relationship between prostate volume, BML, prior BPH surgery and perioperative outcomes, Clavien-Dindo (CD) grade ≥ 2 90-day postoperative complications, positive surgical margins (PSMs), and urinary continence (UC) recovery was evaluated respectively in multivariable linear, logistic and Cox regression models. Complications were collected according to the standardized methodology proposed by EAU guidelines. UC recovery was defined as the use of zero or one safety pad.

RESULTS

Overall, 5.9% and 5.6% had respectively a BML or prior BPH surgery. Median PV was 45 g (range: 14-300). The rate of focal and non-focal PSMs was 8.4% and 17.8%. 53% and 10.9% patients had immediate UC recovery and CD ≥ 2. The 1- and 2-yr UC recovery was 84 and 85%. PV (p = 0.03) and prior BPH surgery (p = 0.02) was associated with longer operative time. BML was independent predictor of time to bladder catheter removal (p = 0.001). PV was independent predictor of PSMs (OR: 1.02; p = 0.009). Prior BPH surgery was associated with lower UC recovery (HR: 0.5; p = 0.03).

CONCLUSION

HR-PCa patients with enlarged prostate have higher risk of PSMs, while patients with prior BPH surgery have suboptimal UC recovery. These findings should help physicians for accurate preoperative counseling and to improve surgical planning in case of HR-PCa patients with challenging features.

Incisional hernia repair after kidney transplantation in a tertiary high-volume center: outcomes from a 10-year retrospective cohort study

BACKGROUND AND AIM

Incisional hernia (IH) after Kidney Transplantation (KT) is a challenging complication due to both technical reasons and patients' complexity. Data regarding outcomes of hernia repair in KT recipients are uncertain, since the biggest part of previous papers focused on risk factors for incisional hernia occurrence and not on its outcomes. Aim of the study was to focus on risk factors for incisional hernia recurrence after surgical repair in KT recipients.

METHODS

Data regarding all consecutive patients undergoing kidney transplantations from January 2011 until September 2020 in Montpellier University Hospital were retrospectively collected from a single institutional database.

RESULTS

After a median follow-up of 48 months (IQR_25-75 31-59), data from 1546 consecutive KT were collected. 83 patients underwent 99 incisional hernia surgeries after KT, with 14 patients that had one recurrence (14.4%) and 2 patients that experienced two recurrences (2.4%). Total recurrence rate was 16.8%. At univariate analysis, the only factor associated with an incisional hernia recurrence was having undergone to at least one previous abdominal surgery other than KT (p value 0.002). Overall morbidity was 15% (n = 15), with most of complications classified as mild (59%). No mortality related to incisional hernia repair occurred.

CONCLUSION

IHs after KT represent an important condition. Its surgical management is challenging due to its anatomical complexity and patient's status. This is the largest sample size in the literature of patients treated for IH after KT and it shows that a previous surgery other than the KT is a risk factor for hernia recurrence after surgical repair, without regarding surgical technique or other comorbidity and therapeutical factors.

Development and validation of a risk nomogram for postoperative acute kidney injury in older patients undergoing liver resection: a pilot study

BACKGROUND

Postoperative acute kidney injury (AKI) is associated with poor clinical outcomes. Early identification of high-risk patients of developing postoperative AKI can optimize perioperative renal management and facilitate patient survival. The present study aims to develop and validate a nomogram to predict postoperative AKI after liver resection in older patients.

METHODS

A retrospective observational study was conducted involving data from 843 older patients scheduled for liver resection at a single tertiary high caseload general hospital between 2012 and 2019. The data were randomly divided into training (70%, n = 599) and validation (30%, n = 244) datasets. The training cohort was used to construct a predictive nomogram for postoperative AKI with the logistic regression model which was confirmed by a validation cohort. The model was evaluated by receiver operating characteristic (ROC) curve, calibration plot, and decision curve analysis in the validation cohort. A summary risk score was also constructed for identifying postoperative AKI patients.

RESULTS

Postoperative AKI occurred in 155 (18.4%) patients and was highly associated with in-hospital mortality (5.2% vs. 0.7%, P <  0.001). The six predictors selected and assembled into the nomogram included age, preexisting chronic kidney disease (CKD), non-steroidal anti-inflammatory drugs (NSAIDs) usage, intraoperative hepatic inflow occlusion, blood loss, and transfusion. The predictive nomogram performed well in terms of discrimination with area under ROC curve (AUC) in training (0.73, 95% confidence interval (CI): 0.68-0.78) and validation (0.71, 95% CI: 0.63-0.80) datasets. The nomogram was well-calibrated with the Hosmer-Lemeshow chi-square value of 9.68 (P = 0.47). Decision curve analysis demonstrated a significant clinical benefit. The summary risk score calculated as the sum of points from the six variables (one point for each variable) performed as well as the nomogram in identifying the risk of AKI (AUC 0.71, 95% CI: 0.66-0.76).

CONCLUSION

This nomogram and summary risk score accurately predicted postoperative AKI using six clinically accessible variables, with potential application in facilitating the optimized perioperative renal management in older patients undergoing liver resection.

TRIAL REGISTRATION

NCT04922866 , retrospectively registered on clinicaltrials.gov on June 11, 2021.

Diagnostic timing dependent characteristics of acute kidney injury following hepatectomy: a retrospective historical cohort analysis

BACKGROUND

The timing of diagnosis of post-hepatectomy acute kidney injury (AKI) has rarely been investigated. The aim of this retrospective study was to reveal the differences between AKI subtypes following hepatectomy, as classified by timing of diagnosis.

METHOD

Post-hepatectomy AKI was classified as very transient AKI (vtAKI; criteria satisfied by the serum creatinine value immediately after surgery) or non-transient AKI (ntAKI; all other AKI types except for vtAKI). Multivariate logistic regression analyses for both AKI types were performed separately to identify differences in known perioperative AKI risk factors. The impacts of each AKI subtype on postoperative complications, hospital stay and renal outcome at discharge were also evaluated.

RESULTS

AKI was diagnosed in 135 of 750 patients (18.0%); 82 and 53 patients were classified as vtAKI and ntAKI, respectively. In multivariate analysis, even among the perioperative factors associated with whole AKI, there were distinct relationships depending on vtAKI or ntAKI. Furthermore, only ntAKI was associated with postoperative complications, longer hospital stays and impaired renal function at discharge.

CONCLUSIONS

Based on the results of this study, future post-hepatectomy AKI studies should only include ntAKI and exclude vtAKI, as vtAKI has minimal clinical impact despite accounting for a significant proportion of AKI patients.

CLINICAL TRIAL REGISTRATIONS

None.

Management of the colonic polyps referred for surgery: an opportunity for improvement

PURPOSE

To examine local practice for non-malignant polyps and to calculate morbidity and mortality associated with bowel resection for this indication.

METHODS

This retrospective cohort study was conducted by reviewing our local gastrointestinal pathology database over a five-year period to identify colonic resections performed for benign polyps. Using search terms "polyp" and "adenoma," 272 cases were identified. Exclusion criteria included: cancer diagnosis, emergency surgeries, multiple resections, and subtotal colectomies for polyposis. 106 patients were included in the study. Primary outcome was perioperative mortality. Secondary outcomes included patient morbidity, characteristics of polyps requiring surgery, and the number of patients referred for a second endoscopic opinion prior to proceeding with surgery.

RESULTS

64 male and 42 female patients with a mean age of 65.3 years (± 8.6 years) underwent colon resection for benign polyps. The mean polyp size was 32.7 mm (± 19.5 mm). 30 patients (28.6%) had polyps equal to or less than 2 cm. Most of the polyps described were sessile (n = 55, 51.9%) and located in the right colon (n = 84, 79.3%). Endoscopic resection was attempted in 31 patients (29.2%), and five cases (4.7%) were referred for a second endoscopic opinion prior to proceeding with surgery. Endoscopists incorrectly felt that polyps were malignant in 62 cases (58.5%). Using Clavien-Dindo classification, most patients had no complications n = 36 (34.0%) or minor complications n = 41 (38.7%). Twelve patients (11.3%) had complications that required antibiotics, blood transfusions, or total parental nutrition. Nine patients (8.5%) required surgical or endoscopic management. Six patients (5.7%) required ICU admission. Mortality rate was 1.9% (n = 2).

CONCLUSION

Surgery for benign colonic polyps is associated with significant morbidity and mortality. These findings reveal a gap in endoscopic management of benign colonic polyps.

External Validation of a Prediction Model for Acute Kidney Injury Following Noncardiac Surgery

IMPORTANCE

The Simple Postoperative AKI Risk (SPARK) index is a prediction model for postoperative acute kidney injury (PO-AKI) in patients undergoing noncardiac surgery. External validation has not been performed.

OBJECTIVE

To externally validate the SPARK index.

DESIGN, SETTING, AND PARTICIPANTS

This single-center retrospective cohort study included adults who underwent noncardiac surgery under general anesthesia from 2007 to 2011. Those with obstetric or urological surgery, estimated glomerular filtration rate (eGFR) of less than 15 mL/min/1.73 m2, preoperative dialysis, or an expected surgical duration of less than 1 hour were excluded. The study was conducted at Nara Medical University Hospital. Data analysis was conducted from January to July 2021.

EXPOSURES

Risk factors for AKI included in SPARK index.

MAIN OUTCOMES AND MEASURES

PO-AKI, defined as an increase in serum creatinine of at least 0.3 mg/dL within 48 hours or 150% compared with preoperative baseline value or urine output of less than 0.5 mL/kg/h for at least 6 hours within 1 week after surgery, and critical AKI, defined as either AKI stage 2 or greater and/or any AKI connected to postoperative death or requiring kidney replacement therapy before discharge. The discrimination and calibration of the SPARK index were examined with area under the receiver operating characteristic curves (AUC) and calibration plots, respectively.

RESULTS

Among 5135 participants (2410 [46.9%] men), 303 (5.9%) developed PO-AKI, and 137 (2.7%) developed critical AKI. Compared with the SPARK cohort, participants in our cohort were older (median [IQR] age, 56 [44-66] years vs 63 [50-73] years), had lower baseline eGFR (median [IQR], 82.1 [71.4-95.1] mL/min/1.73 m2 vs 78.2 [65.6-92.2] mL/min/1.73 m2), and had a higher prevalence of comorbidities (eg, diabetes: 3956 of 51 041 [7.8%] vs 802 [15.6%]). The incidence of PO-AKI and critical AKI increased as the scores on the SPARK index increased. For example, 10 of 593 participants (1.7%) in SPARK class A, indicating lowest risk, experienced PO-AKI, while 53 of 332 (16.0%) in SPARK class D, indicating highest risk, experienced PO-AKI. However, AUCs for PO-AKI and critical AKI were 0.67 (95% CI, 0.63-0.70) and 0.62 (95% CI, 0.57-0.67), respectively, and the calibration was poor (PO-AKI: y = 0.24x + 3.28; R2 = 0.86; critical AKI: y = 0.20x + 2.08; R2 = 0.51). Older age, diabetes, expected surgical duration, emergency surgery, renin-angiotensin-aldosterone system blockade use, and hyponatremia were not associated with PO-AKI in our cohort, resulting in overestimation of the predicted probability of AKI in our cohort.

CONCLUSIONS AND RELEVANCE

In this study, the incidence of PO-AKI increased as the scores on the SPARK index increased. However, the predicted probability might not be accurate in cohorts with older patients with more comorbidities.

Skin autofluorescence as a novel predictor of acute kidney injury after liver resection

Abstract

Background

Skin autofluorescence (SAF) reflects accumulation of advanced glycation end-products (AGEs). The aim of this study was to evaluate predictive usefulness of SAF measurement in prediction of acute kidney injury (AKI) after liver resection.

Methods

This prospective observational study included 130 patients undergoing liver resection. The primary outcome measure was AKI. SAF was measured preoperatively and expressed in arbitrary units (AU).

Results

AKI was observed in 32 of 130 patients (24.6%). SAF independently predicted AKI (p = 0.047), along with extent of resection (p = 0.019) and operative time (p = 0.046). Optimal cut-off for SAF in prediction of AKI was 2.7 AU (area under the curve [AUC] 0.611), with AKI rates of 38.7% and 20.2% in patients with high and low SAF, respectively (p = 0.037). Score based on 3 independent predictors (SAF, extent of resection, and operative time) well stratified the risk of AKI (AUC 0.756), with positive and negative predictive values of 59.3% and 84.0%, respectively. In particular, SAF predicted AKI in patients undergoing major and prolonged resections (p = 0.010, AUC 0.733) with positive and negative predictive values of 81.8%, and 62.5%, respectively.

Conclusions

AGEs accumulation negatively affects renal function in patients undergoing liver resection. SAF measurement may be used to predict AKI after liver resection, particularly in high-risk patients.

Development and validation of a prediction score for safe outpatient colorectal resections

BACKGROUND

Avoiding unnecessary inpatient stay may decrease hospital-acquired complications and costs while increasing patient satisfaction. This study aimed to develop and validate a score to identify patients eligible for safe same-day discharge after colorectal resections.

METHODS

This bi-institutional retrospective cohort study included consecutive patients undergoing elective colon and rectal resections (2011-2018) for benign and malignant indications. Two multivariable logistic models were developed based on demographic and surgical risk factors to predict a combined endpoint (ileus, anastomotic leak, intra-abdominal abscess, and readmission). Development and validation datasets were randomly sampled from the entire cohort. Areas under the receiver operating characteristic curves (AUC) were evaluated, and Hosmer-Lemeshow goodness-of-fit tests were used to assess validation model fit.

RESULTS

Of 5,389 patients, 1,182 (21.9%) experienced at least one complication of the combined endpoint. Male gender, open surgery, ASA ≥3, wound class ≥3, ileostomy, surgical duration >3 hours, and perioperative IV fluids >3 L all had significantly greater odds of the combined endpoint in the parsimonious multivariable model (all P < .05). The reduced model considering only the 4 variables with the highest OR (>1.5) contained open surgery, ASA ≥3, wound class ≥3, and surgical duration ≥3 hours as predictors (all P < .05, AUC of 0.65; 95% CI 0.63, 0.68). Both the parsimonious model and the reduced model demonstrated no lack of fit in the validation cohort.

CONCLUSION

The suggested score composed of preand intraoperative items may help physicians decide on patients' same-day discharge after colorectal resection.

Acute kidney injury following hepatectomy and its impact on long-term survival for patients with hepatocellular carcinoma

Background

Acute kidney injury (AKI) is increasingly being recognized after hepatectomy. This study aimed to identify factors predicting its occurrence and its impact on long-term outcome among patients with hepatocellular carcinoma (HCC).

Methods

This was a retrospective analysis of the incidence of AKI, factors predicting its occurrence, and its impact on patients undergoing hepatectomy between September 2007 and December 2018. A subgroup analysis included patients with histologically proven HCC.

Results

The incidence of AKI was 9.2 per cent in 930 patients. AKI was associated with increased mortality, morbidity, posthepatectomy liver failure (PHLF), and a longer hospital stay. On multivariable analysis, study period December 2013 to December 2018, diabetes mellitus, mean intraoperative BP below 72.1 mmHg, operative blood loss exceeding 377ml, high Model for End-Stage Liver Disease (MELD) score, and PHLF were predictive factors for AKI. Among 560 patients with HCC, hypertension, BP below 76.9 mmHg, blood loss greater than 378ml, MELD score, and PHLF were predictive factors. The 1-, 3-, and 5-year overall survival rates were 74.1, 59.2, and 51.6 per cent respectively for patients with AKI, and 91.8, 77.9, and 67.3 per cent for those without AKI. Corresponding 1-, 3-, and 5-year disease-free survival rates were 56.9, 42.3, and 35.4 per cent respectively in the AKI group, and 71.7, 54.5, and 46.2 per cent in the no-AKI group. AKI was an independent predictor of survival in multivariable analysis.

Conclusion

AKI is associated with longer hospital stay, and higher morbidity and mortality rates. It is also associated with shorter long-term survival among patients with HCC. To avoid AKI, control of blood loss and maintaining a reasonable BP (72–77 mmHg) during hepatectomy is important.

Impact of acute kidney injury after extended liver resections

BACKGROUND

Complex liver resection is a risk factor for the development of AKI, which is associated with increased morbidity and mortality. Aim of this study was to assess risk factors for acute kidney injury (AKI) and its impact on outcome for patients undergoing complex liver surgery.

METHODS

AKI was defined according to the KDIGO criteria. Primary endpoint was the occurrence of AKI after liver resection. Secondary endpoints were complications and mortality.

RESULTS

Overall, 146 patients undergoing extended liver resection were included in the study. The incidence of AKI was 21%. The incidence of chronic kidney disease (CKD) and hepatocellular carcinoma were significantly higher in patients with AKI. In the AKI group, the proportion of extended right hepatectomies was the highest (53%), followed by ALPPS (43%). Increased intraoperative blood loss, increased postoperative complications and perioperative mortality was associated with AKI. Besides age and CKD, ALPPS was an independent risk factor for postoperative AKI. A small future liver remnant seemed to increase the risk of AKI in patients undergoing ALPPS.

CONCLUSION

Following extended liver resection, AKI is associated with an increased morbidity and mortality. ALPPS is a major independent risk factor for the development of AKI and a sufficient future liver remnant could avoid postoperative AKI.

Association of Preoperative Prognostic Nutritional Index and Postoperative Acute Kidney Injury in Patients Who Underwent Hepatectomy for Hepatocellular Carcinoma

Various biological indicators are reportedly associated with postoperative acute kidney injury (AKI) in the surgical treatment of hepatocellular carcinoma (HCC). However, only a few studies have evaluated the association between the preoperative prognostic nutritional index (PNI) and postoperative AKI. This study evaluated the association of the preoperative PNI and postoperative AKI in HCC patients. We retrospectively analyzed 817 patients who underwent open hepatectomy between December 2007 and December 2015. Multivariate regression analysis was performed to evaluate the association between the PNI and postoperative AKI. Additionally, we evaluated the association between the PNI and outcomes such as postoperative renal replacement therapy (RRT) and mortality. Cox regression analysis was performed to assess the risk factors for one-year and five-year mortality. In the multivariate analysis, high preoperative PNI was significantly associated with a lower incidence of postoperative AKI (odds ratio (OR): 0.92, 95% confidence interval (CI): 0.85 to 0.99, p = 0.021). Additionally, diabetes mellitus and the use of synthetic colloids were significantly associated with postoperative AKI. PNI was associated with postoperative RRT (OR: 0.76, 95% CI: 0.60 to 0.98, p = 0.032) even after adjusting for other potential confounding variables. In the Cox regression analysis, high PNI was significantly associated with low one-year mortality (Hazard ratio (HR): 0.87, 95% CI: 0.81 to 0.94, p < 0.001), and five-year mortality (HR: 0.93, 95% CI: 0.90–0.97, p < 0.001). High preoperative PNI was significantly associated with a lower incidence of postoperative AKI and low mortality. These results suggest that the preoperative PNI might be a predictor of postoperative AKI and surgical prognosis in HCC patients undergoing open hepatectomy.

Pre-operative N-terminal pro-B-type natriuretic peptide for prediction of acute kidney injury after noncardiac surgery: A retrospective cohort study

BACKGROUND

Acute kidney injury (AKI) is associated with poor outcomes after noncardiac surgery. Whether pre-operative N-terminal pro-B-type natriuretic peptide (NT-proBNP) predicts AKI after noncardiac surgery is unclear.

OBJECTIVE

To investigate the predictive role of pre-operative NT-proBNP on postoperative AKI.

DESIGN

Retrospective cohort study.

SETTING

Nanfang Hospital, Southern Medical University, China.

PATIENTS

Adult patients who had a serum creatinine and NT-proBNP measurement within 30 pre-operative days and at least one serum creatinine measurement within 7 days after noncardiac surgery between February 2008 and May 2018 were identified.

MAIN OUTCOME MEASURES

The primary outcome was postoperative AKI, defined by the kidney disease: improving global outcomes creatinine criteria.

RESULTS

In all, 6.1% (444 of 7248) of patients developed AKI within 1 week after surgery. Pre-operative NT-proBNP was an independent predictor of AKI after adjustment for clinical variables (OR comparing top to bottom quintiles 2.29, 95% CI, 1.47 to 3.65, P < 0.001 for trend; OR per 1-unit increment in natural log transformed NT-proBNP 1.27, 95% CI, 1.16 to 1.39). Compared with clinical variables alone, the addition of NT-proBNP improved model fit, modestly improved the discrimination (change in area under the curve from 0.764 to 0.773, P = 0.005) and reclassification (continuous net reclassification improvement 0.210, 95% CI, 0.111 to 0.308, improved integrated discrimination 0.0044, 95% CI, 0.0016 to 0.0072) of AKI and non-AKI cases, and achieved higher net benefit in decision curve analysis.

CONCLUSIONS

Pre-operative NT-proBNP concentrations provided predictive information for AKI in a cohort of patients undergoing noncardiac surgery, independent of and incremental to conventional risk factors. Prospective studies are required to confirm this finding and examine its clinical impact.

TRIAL REGISTRATION

Chinese Clinical Trial Registry, ChiCTR1900024056. www.chictr.org.cn/showproj.aspx?proj=40385.

External Validation of the Acute Kidney Injury Risk Prediction Score for Critically Ill Surgical Patients Who Underwent Major Non-Cardiothoracic Surgery

Background: Acute kidney injury (AKI) is a common complication encountered in an intensive care unit (ICU). In 2020, the AKI prediction score was developed specifically for critically ill surgical patients who underwent major non-cardiothoracic surgeries. This study aimed to externally validate the AKI prediction score in terms of performance and clinical utility. Methods: External validation was carried out in a prospective cohort of patients admitted to the ICU of the Faculty of Medicine Vajira Hospital between September 2014 and September 2015. The endpoint was AKI within seven days following ICU admission. Discriminative ability was based on the area under the receiver operating characteristic curves (AuROC). Calibration and clinical usefulness were evaluated. Results: A total of 201 patients were included in the analysis. AKI occurred in 37 (18.4%) patients. The discriminative ability dropped from good in the derivation cohort, to acceptable in the validation cohort (0.839 (95%CI 0.825–0.852) vs. 0.745 (95%CI 0.652–0.838)). No evidence of lack-of-fit was identified (p = 0.754). The score had potential clinical usefulness across the range of threshold probability from 10 to 50%. Conclusions: The AKI prediction score showed an acceptable discriminative performance and calibration with potential clinical usefulness for predicting AKI risk in surgical patients who underwent major non-cardiothoracic surgery.

Bioelectrical impedance analysis for predicting postoperative complications and survival after liver resection for hepatocellular carcinoma

Background

Bioelectrical impedance analysis provides information on body composition and nutritional status. However, it's unclear whether the preoperative edema index or phase angle predicts postoperative complication or mortality in patients with hepatocellular carcinoma (HCC). Thus, we investigated whether preoperative bioelectrical impedance analysis could predict postoperative complications and survival in patients with HCC.

Methods

Seventy-nine patients who underwent hepatectomy for hepatocellular carcinoma were prospectively enrolled and bioelectrical impedance analysis was performed before surgery. Postoperative ascites or acute kidney injury and patients' survival were monitored after surgery.

Results

Among 79 patients, 35 (44.3%) developed ascites or acute kidney injury after hepatectomy. In multivariate analysis, a high preoperative edema index (extracellular water/total body water) (>0.384) (odds ratio 3.96; 95% confidence interval: 1.03-15.17; P=0.045) and higher fluid infusion during surgery (odds ratio 1.36; 95% confidence interval: 1.04-1.79; P=0.026) were identified as significant risk factors for ascites or acute kidney injury after hepatectomy. Subgroup analyses showed that the edema index was a significant predictor of ascites or acute kidney injury in patients with cirrhosis. Tumor size was the only significant predictive factor for short-term survival after hepatectomy.

Conclusions

The preoperative edema index using bioelectrical impedance analysis can be used as a predictor of post-hepatectomy complication, especially in patients with liver cirrhosis.

Incidence and Predictors of Acute Kidney Injury in Patients Undergoing Elective Hepatic Resection for Malignant Tumors: A 3-year Prospective Observational Study

Background

Acute kidney injury (AKI) is common in patients undergoing major surgeries, and leads to the need for renal replacement therapy and increased morbidity, intensive care unit (ICU) and hospital length of stay (LOS), cost, and mortality. We evaluated the incidence and predictors of postoperative AKI in patients undergoing hepatic resections and their short-term outcomes.

Materials and methods

This prospective observational study was conducted over a 3-year period in 180 patients undergoing elective hepatic resections for a variety of indications. We used the Acute Kidney Injury Network criteria to determine the incidence of AKI at 72 hours. Perioperative variables contributing to the development of AKI and the short-term postoperative outcomes of patients were evaluated.

Results

Postoperative AKI occurred in 29.4% of patients. Persistent renal dysfunction was seen in five patients. Development of AKI was associated with hepatic failure (18.5 vs 5.5%, p < 0.005), prolonged ICU (2 vs 1 days, p < 0.001) and hospital LOS (11 vs 8 days, p < 0.004), and increased ICU and hospital mortality (9.6 vs 1.4%, p < 0.02). Age [OR (odds ratio) 1.033, 95% CI (confidence interval) 1.003–1.065, p = 0.03], BMI (body mass index) (OR 1.131, 95% CI 1.043–1.227, p = 0.003), and need for postoperative ventilation (OR 3.456, 95% CI 1.593–7.495, p = 0.002) were independent predictors of AKI.

Conclusion

AKI after elective hepatic resection occurred in nearly one-third of our patients. Persistent renal dysfunction was seen in five patients. Age, BMI, and need for postoperative ventilation were independent predictors of postoperative AKI. (CTRI reg. No.: CTRI/2016/06/007044).

How to cite this article

Joshi M, Milmile R, Dhakane P, Bhosale SJ, Kulkarni AP. Incidence and Predictors of Acute Kidney Injury in Patients Undergoing Elective Hepatic Resection for Malignant Tumors: A 3-year Prospective Observational Study. Indian J Crit Care Med 2021;25(4):398–404.

Influence of diabetes on short-term outcome after major hepatectomy: an underestimated risk?

BACKGROUND

Patient-related risk factors such as diabetes mellitus and obesity are increasing in western countries. At the same time the indications for liver resection in both benign and malignant diseases have been significantly extended in recent years. Major liver resection is performed more frequently in a patient population of old age, comorbidity and high rates of neoadjuvant chemotherapy. The aim of this study was to evaluate whether diabetes mellitus, obesity and overweight are risk factors for the short-term post-operative outcome after major liver resection.

METHODS

Four hundred seventeen major liver resections (≥ 3 segments) were selected from a prospective database. Exclusion criteria were prior liver resection in patient's history and synchronous major intra-abdominal procedures. Overweight was defined as BMI ≥ 25 kg/m2 and < 30 kg/m2 and obesity as BMI ≥ 30 kg/m2. Primary end point was 90-day mortality and logistic regression was used for multivariate analysis. Secondary end points included morbidity, complications according to Clavien-Dindo classification, unplanned readmission, bile leakage, and liver failure. Morbidity was defined as occurrence of a post-operative complication during hospital stay or within 90 days postoperatively.

RESULTS

Fifty-nine patients had diabetes mellitus (14.1%), 48 were obese (11.6%) and 147 were overweight (35.5%). There were no statistically significant differences in mortality rates between the groups. In the multivariate analysis, diabetes was an independent predictor of morbidity (OR = 2.44, p = 0.02), Clavien-Dindo grade IV complications (OR = 3.6, p = 0.004), unplanned readmission (OR = 2.44, p = 0.04) and bile leakage (OR = 2.06, p = 0.046). Obese and overweight patients did not have an impaired post-operative outcome compared patients with normal weight.

CONCLUSIONS

Diabetes has direct influence on the short-term postoperative outcome with an increased risk of morbidity but not mortality. Preoperative identification of high-risk patients will potentially decrease complication rates and allow for individual patient counseling as part of a shared decision-making process. For obese and overweight patients, major liver resection is a safe procedure.

Association of intraoperative hypotension with acute kidney injury after liver resection surgery: an observational cohort study

Background

Acute kidney injury (AKI) is a major complication following liver resection. The aim of this study was to determine the risk factors for AKI after hepatic resection and whether intraoperative hypotension (IOH) was related to AKI.

Methods

Adult patients (≥ 18 years) undergoing liver resection between November 2017 and November 2019 at our hospital were retrospectively reviewed. AKI was defined as ≥50% increase in serum creatinine from baseline value within 48 h after surgery. IOH was defined as the lowest absolute mean arterial pressure (MAP) < 65 mmHg for more than 10 cumulative minutes during the surgery. Patients were divided into AKI group and non-AKI group, and were stratified by age ≥ 65 years.

Results

796 patients who met our inclusion and exclusion criteria were analyzed. After multivariable regression analysis, the IOH (OR, 2.565; P = 0.009) and age ≥ 65 years (OR, 2.463; P = 0.008) were risk factors for AKI. The IOH (OR, 3.547; P = 0.012) and received red blood cell (OR, 3.032; P = 0.036) were risk factors of AKI in age ≥ 65 years patients.

Conclusions

The IOH and age ≥ 65 years were risk factors for postoperative AKI, and IOH was associated with AKI in age ≥ 65 years patients following liver resection.

Supplementary information

Supplementary information accompanies this paper at 10.1186/s12882-020-02109-9.

Renal Impairment Is Associated with Reduced Outcome After Associating Liver Partition and Portal Vein Ligation for Staged Hepatectomy

BACKGROUND

Impaired postoperative renal function is associated with increased morbidity and mortality after liver resection. The role of impaired renal function in the two-stage hepatectomy setting of associating liver partition and portal vein ligation for staged hepatectomy (ALPPS) is unknown.

METHODS

An international multicenter cohort of ALPPS patients captured in the ALPPS Registry was analyzed. Particular attention was drawn to the renal function in the interstage interval to determine outcome after stage 2 surgery. Interstage renal impairment (RI) was defined as an increase of serum creatinine of ≥ 0.3 mg/dl referring to a preoperative value or an increase of serum creatinine of ≥ 1.5× of the preoperative value on the fifth postoperative day after stage 1.

RESULTS

A total of 705 patients were identified of which 7.5% had an interstage RI. Patients developing an interstage RI were significantly older. During stage 1, a longer operation time, higher rate of intraoperative transfusions, and additional procedures were observed in patients that developed interstage RI. After stage 1, interstage RI patients had more major complications and higher interstage mortality (1% vs. 8%, p < 0.001). Furthermore, these patients developed more and severe complications after completion of stage 2. Mortality of patients with interstage RI was 38% vs. 8% without interstage RI. In 41% of patients with interstage RI, the renal function recovered before stage 2; however, the mortality after stage 2 remained 28% in those patients. Risk factors for the development of an interstage RI were age over 67 years, prolonged operative time, and additional procedure during stage 1.

CONCLUSION

This study shows that interstage RI is a predictor for interstage and post-stage 2 morbidity and perioperative mortality. The causality of impaired renal function on outcome, however, remains unknown. Interstage RI may directly cause adverse outcome but may also be a surrogate marker for major complications.

Robotic hepatic parenchymal transection: a two-surgeon technique using ultrasonic dissection and irrigated bipolar coagulation

Liver transection is the most challenging part of hepatectomy due to the risk of hemorrhage which is associated with postoperative morbidity and mortality and reduced long-term survival. Parenchymal ultrasonic dissection (UD) with bipolar coagulation (BPC) has been widely recognized as a safe, effective, and standard technique during open and laparoscopic hepatectomy. We here introduce our technique of robotic liver transection using UD with BPC and report on short-term perioperative outcomes. From a single-institution prospective liver surgery database, we identified patients who underwent robotic liver resection. Demographic, anesthetic, perioperative, and oncologic data were analyzed. Fifty patients underwent robotic liver resection using UD and BPC for liver malignancies (n = 42) and benign lesions (n = 8). The median age of the patients was 67 years and 28 were male. According to the difficulty scoring system, 60% (n = 30) of liver resection were considered difficult. Three cases (6%) were converted to open surgery. The median operative time was 240 min, and the median estimated blood loss was 200 ml; 2 patients required operative transfusions. The overall complication rate was 38% (grade I, 29; grade II, 15; grade III, 3; grade IV, 1). Seven patients (14%) experienced biliary leakage. The median length of hospital stay post-surgery was 7 (range 3-20) days. The R0 resection rate was 92%. Robotic parenchymal transection using UD and irrigated BPC appears a simple, safe, and effective technique. However, our results must be confirmed in larger series or in randomized controlled trials.

Acute kidney injury risk prediction score for critically-ill surgical patients

Background

There has been a global increase in the incidence of acute kidney injury (AKI), including among critically-ill surgical patients. AKI prediction score provides an opportunity for early detection of patients who are at risk of AKI; however, most of the AKI prediction scores were derived from cardiothoracic surgery. Therefore, we aimed to develop an AKI prediction score for major non-cardiothoracic surgery patients who were admitted to the intensive care unit (ICU).

Methods

The data of critically-ill patients from non-cardiothoracic operations in the Thai Surgical Intensive Care Unit (THAI-SICU) study were used to develop an AKI prediction score. Independent prognostic factors from regression analysis were included as predictors in the model. The outcome of interest was AKI within 7 days after the ICU admission. The AKI diagnosis was made according to the Kidney Disease Improving Global Outcomes (KDIGO)-2012 serum creatinine criteria. Diagnostic function of the model was determined by area under the Receiver Operating Curve (AuROC). Risk scores were categorized into four risk probability levels: low (0–2.5), moderate (3.0–8.5), high (9.0–11.5), and very high (12.0–16.5) risk. Risk of AKI was presented as likelihood ratios of positive (LH+).

Results

A total of 3474 critically-ill surgical patients were included in the model; 333 (9.6%) developed AKI. Using multivariable logistic regression analysis, older age, high Sequential Organ Failure Assessment (SOFA) non-renal score, emergency surgery, large volume of perioperative blood loss, less urine output, and sepsis were identified as independent predictors for AKI. Then AKI prediction score was created from these predictors. The summation of the score was 16.5 and had a discriminative ability for predicting AKI at AuROC = 0.839 (95% CI 0.825–0.852). LH+ for AKI were: low risk = 0.117 (0.063–0.200); moderate risk = 0.927 (0.745–1.148); high risk = 5.190 (3.881–6.910); and very high risk = 9.892 (6.230–15.695), respectively.

Conclusions

The function of AKI prediction score to predict AKI among critically ill patients who underwent non-cardiothoracic surgery was good. It can aid in early recognition of critically-ill surgical patients who are at risk from ICU admission. The scores could guide decision making for aggressive strategies to prevent AKI during the perioperative period or at ICU admission.

Trial registration

TCTR20190408004, registered on April 4, 2019.

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.

A comparative study of machine learning algorithms for predicting acute kidney injury after liver cancer resection

Objective

Machine learning methods may have better or comparable predictive ability than traditional analysis. We explore machine learning methods to predict the likelihood of acute kidney injury after liver cancer resection.

Methods

This is a secondary analysis cohort study. We reviewed data from patients who had undergone resection of primary hepatocellular carcinoma between January 2008 and October 2015.

Results

The analysis included 1,173 hepatectomy patients, 77 (6.6%) of whom had AKI and 1,096 (93.4%) who did not. The importance matrix for the Gbdt algorithm model shows that age, cholesterol, tumor size, surgery duration and PLT were the five most important parameters. Figure 1 shows that Age, tumor size and surgery duration had weak positive correlations with AKI. Cholesterol and PLT also had weak negative correlations with AKI. The models constructed by the four machine learning algorithms in the training group were compared. Among the four machine learning algorithms, random forest and gbm had the highest accuracy, 0.989 and 0.970 respectively. The precision of four of the five algorithms was 1, random forest being the exception. Among the test group, gbm had the highest accuracy (0.932). Random forest and gbm had the highest precision, both being 0.333. The AUC values for the four algorithms were: Gbdt (0.772), gbm (0.725), forest (0.662) and DecisionTree (0.628).

Conclusions

Machine learning technology can predict acute kidney injury after hepatectomy. Age, cholesterol, tumor size, surgery duration and PLT influence the likelihood and development of postoperative acute kidney injury.

Acute kidney injury after liver surgery: does postoperative urine output correlate with postoperative serum creatinine?

BACKGROUND

Acute kidney injury (AKI) after hepatectomy occurs in around 10% of cases. AKI is often defined based only on postoperative serum creatinine increase. This study aimed to assess if postoperative urine output (UO) correlated with serum creatinine after hepatectomy.

METHODS

All consecutive hepatectomy patients (2010-2016) were assessed. AKI was defined according to KDIGO criteria: serum creatinine increase ≥26.5 μmol/l, creatinine increase ≥1.5x baseline creatinine, or postoperative oliguria. Oliguria was defined as daily mean UO <0.5 mL/kg/h. AKI was subdivided into creatinine-based or oliguria-based AKI according to the defining criterion.

RESULTS

Out of 285 patients, AKI was observed in 79 cases (28%). Creatinine-based AKI occurred in 25 patients (9%) and oliguria-based only AKI in 54 patients (19%). Ten patients fulfilled both criteria (4%). Postoperative UO correlated poorly with postoperative serum creatinine level in both whole cohort (rho = -0.34, p <0.001) and AKI subgroup (rho = -0.189, p = 0.124). No association was found between postoperative oliguria and postoperative serum creatinine increase (HR = 0.5, 95%CI: 0.2-1.9, p = 0.341). On multivariable analysis, operation duration >360 minutes was the only predictor of creatinine increase (HR = 3.6, 95%CI: 1.1-11.4, p = 0.032).

CONCLUSION

Postoperative UO showed poor correlation with postoperative serum creatinine both in all patients and AKI patients. Surgery duration >360 minutes appeared as the only independent predictor of postoperative serum creatinine increase.

Acute kidney injury after associating liver partition and portal vein ligation for staged hepatectomy for hepatocellular carcinoma: two case reports and a literature review

Associating liver partition and portal vein ligation for staged hepatectomy (ALPPS) is used for avoiding postoperative live failure caused by insufficient future liver remnant (FLR) after major liver resection. However, ALPPS accompanied by high morbidity and mortality. The surgeons focus their attention mainly on the common complications such as bile leak, bleeding, infection and liver failure. Acute kidney injury (AKI) is a relatively rare postoperative complication, and get less attention. However, once AKI occurred after the surgery, it will seriously affect the prognosis of patients. We firstly report two cases of postoperative AKI after ALPPS in hepatocellular carcinoma with liver cirrhosis. Case 1, a 61-year-old male, chief complaint upper abdominal pain for half a month, medical examination found a huge liver space-occupying lesion. The clinical diagnosis was liver cancer, and ALPPS was performed. After the first step of surgery, delayed renal replacement therapy (RRT) was initiated when stage 3 AKI diagnosed. Although the second step surgery completed successfully, the patient eventually died of multiple organ dysfunction syndrome (MODS) induced by gastrointestinal bleeding. Case 2, a 64-year-old male chief complaint right liver mass present to our hospital, with a small FLR. Stage 2 AKI was diagnosed after the first step of ALPPS, early RRT was started immediately. Renal function gradually recovered, and the second step surgery was completed. The patient discharged with a good condition, found no recurrence in the latest follow-up. ALPPS for hepatocellular carcinoma with liver cirrhosis cases, more likely to happen AKI. More strict patient screening criteria, early RRT may improve the prognosis.

Development of a risk stratification-based model for prediction of acute kidney injury in critically ill patients

Acute kidney injury (AKI) is a complex syndrome with a variety of possible etiologies and symptoms. It is characterized by high mortality and poor recovery of renal function. The incidence and mortality rates of patients with AKI in intensive care units are extremely high. It is generally accepted that early identification and prompt treatment of AKI are essential to improve outcomes. This study aimed to develop a model based on risk stratification to identify and diagnose early stage AKI for improved prognosis in critically ill patients.This was a single-center, retrospective, observational study. Based on relevant literature, we selected 13 risk factors (age, sex, hypertension, diabetes, coronary heart disease, chronic kidney disease, total bilirubin, emergency surgery, mechanical ventilation, sepsis, heart failure, cancer, and hypoalbuminemia) for AKI assessment using the Kidney Disease Improving Global Outcomes (KDIGO) diagnostic criteria. Univariate and multivariate analyses were used to determine risk factors for eventual entry into the predictive model. The AKI predictive model was established using binary logistic regression, and the area under the receiver operating characteristic curve (AUROC or AUC) was used to evaluate the predictive ability of the model and to determine critical values.The AKI predictive model was established using binary logistic regression. The AUROC of the predictive model was 0.81, with a sensitivity of 69.8%, specificity of 83.4%, and positive likelihood ratio of 4.2.A predictive model for AKI in critically ill patients was established using 5 related risk factors: heart failure, chronic kidney disease, emergency surgery, sepsis, and total bilirubin; however, the predictive ability requires validation.

Acute kidney injury following resection of hepatocellular carcinoma: prognostic value of the acute kidney injury network criteria

Background

Acute kidney injury (AKI) is associated with increased morbidity and mortality after liver resection. Patients with hepatocellular carcinoma (HCC) have a higher risk of AKI owing to the underlying association between hepatic and renal dysfunction. Use of the Acute Kidney Injury Network (AKIN) diagnostic criteria is recommended for patients with cirrhosis, but remains poorly studied following liver resection. We compared the prognostic value of the AKIN creatinine and urine output criteria in terms of postoperative outcomes following liver resection for HCC.

Methods

All patients who underwent a liver resection for HCC from January 2010 to June 2016 were included. We used AKIN urine output and creatinine criteria to assess for AKI within 48 hours of surgery.

Results

Eighty liver resections were performed during the study period. Cirrhosis was confirmed in 80%. Median hospital stay was 9 (interquartile range 7–12) days, and 30-day mortality was 2.5%. The incidence of AKI was higher based on the urine output than on the creatinine criterion (53.8% v. 20%), and was associated with prolonged hospitalization and 30-day postoperative mortality when defined by serum creatinine (hospital stay: 11.2 v. 20.1 d, p = 0.01; mortality: 12.5% v. 0%, p < 0.01), but not urine output (hospital stay: 15.6 v. 10 d, p = 0.05; mortality: 2.3% v. 2.7%, p > 0.99).

Conclusion

The urine output criterion resulted in an overestimation of AKI and compromised the prognostic value of AKIN criteria. Revision may be required to account for the exacerbated physiologic postoperative reduction in urine output in patients with HCC.

Acute kidney injury after hepatectomy can be reasonably predicted after surgery

BACKGROUND

Hepatectomy presents unique challenges potentially heightening acute kidney injury (AKI) risk, but the full spectrum of risk factors has not been identified.

METHODS

Data for hepatectomy patients in the 2016 American College of Surgeons National Surgical Quality Improvement Program (n = 3,814) was randomly split into derivation (70%) and validation (30%) cohorts. AKI was defined as an increase in serum creatinine ≥0.3 mg/dl or ≥1.5-fold above the preoperative value within 30 days of surgery. Multivariable logistic regression assessed preoperative and intraoperative risk factors for AKI.

RESULTS

Of 2,692 patients (derivation cohort), 432 (16%) developed AKI. Risk factors were the following: age (years; adjusted odds ratio [aOR] 1.016 [95% confidence interval 1.006-1.026], female sex (aOR 0.65 [0.51-0.82]), body mass index (kg/m² ; aOR 1.043 [1.024-1.062]), diabetes (aOR 1.71 [1.31-2.24]), hypertension (aOR 1.66 [1.30-2.13]), hematocrit (%; aOR 0.944 [0.924-0.966]), operative time (min; aOR 1.004 [1.003-1.004]), planned open procedure (aOR 2.00 [1.47-2.73]), and Pringle maneuver (aOR 1.36 [1.07-1.72]). The areas under the curve of the receiver operating characteristic curves were 0.74 (95% CI 0.71-0.76) and 0.71 (95% CI 0.67-0.75) in the derivation and validation cohorts, respectively.

CONCLUSIONS

Postoperative AKI affects one in six hepatectomy patients; preoperative and intraoperative factors can predict the risk of postoperative AKI.

Comparison of Perioperative Renal Function Between Epidural and Intravenous Patient-Controlled Analgesia After Living-Donor Hepatectomy: A Retrospective Study

BACKGROUND

Sympathetic blockade associated with epidural analgesia was reported to be a risk factor for acute kidney injury (AKI) following liver resection. The purpose of this study was to compare the incidence of AKI after living-donor hepatectomies according to the type of patient-controlled analgesia (PCA).

METHODS

A total of 316 patients after living-donor hepatectomy were retrospectively analyzed; 148 patients in the epidural PCA group and 168 patients in the intravenous (IV) PCA group were evaluated. AKI was defined as an increase in serum creatinine ≥0.3 mg/dL, ie, 1.5-fold from the baseline, or a reduction in the urine output in the first 48 hours after surgery, based on the Acute Kidney Injury Network criteria. Logistic regression analysis was performed to identify the independent risk factors for AKI after living-donor hepatectomy.

RESULTS

Baseline characteristics were similar between the 2 groups except the age. Volumes of fluids and colloids administered intraoperatively were greater in the epidural PCA group (P < .001 and P = .006, respectively). The incidence of AKI did not show significant differences between the 2 groups (8.1% vs 7.1%; P = .747). In multivariate analysis, preoperative serum alanine transaminase level ≥50 U/L was identified as a risk factor for postoperative AKI. However, epidural PCA failed to be a risk factor for postoperative AKI.

CONCLUSIONS

The type of PCA did not affect the incidence of postoperative AKI after living-donor hepatectomy. Despite significant differences in the postoperative hemodynamics, the incidence of AKI was similar between 2 groups.

Severe acute kidney injury following major liver resection without portal clamping: incidence, risk factors, and impact on short-term outcomes

BACKGROUND

Acute kidney injury (AKI) following major hepatectomy (MH) remains inadequately investigated. This retrospective study aimed to assess the risk factors and prognostic value of AKI on short-term outcomes following MH without portal pedicle clamping.

METHODS

From January 2014 through June 2017, 111 consecutive patients underwent MH without portal pedicle clamping, but with intraoperative low-crystalloid infusion. Kidney Disease Improving Global Outcomes stages II and III were classified as severe AKI.

RESULTS

A total of 102 patients did not develop AKI or only AKI stage I (92%, control group), whereas 9 patients developed severe AKI (8%, severe AKI group). Hepatectomy (P = 0.002) and surgery (P = 0.011) durations were longer in the severe AKI group. Clavien-Dindo grades 3 to 5 morbidity (55% versus 9%, P = 0.001), liver failure (P = 0.017), and 90-day mortality (33% versus 2%, P = 0.003) were significantly higher in the severe AKI group. After a multivariate analysis, the duration of hepatectomy (cut-off: 250 min; P = 0.029) and urea serum levels on postoperative day 3 (P = 0.006) were identified as independent predictors of severe AKI.

DISCUSSION

Severe AKI, is common with increased duration of hepatectomy, was associated with poor short-term outcomes, and can be predicted by operative duration greater than 250 minutes.

Increased Risk of Complications After Pancreatoduodenectomy in Uninephrectomized Patients

Objective:

The study objective is to investigate the impact of unilateral nephrectomy on the complications after pancreatoduodenectomy (PD).

Summary of background data:

Preoperative renal insufficiency is a risk factor for postoperative complications and mortality after various types of surgery. However, the specific postoperative risks in uninephrectomized (UN) patients are largely unknown.

Methods:

Between January 2010 and June 2014, a total of 177 patients underwent PD at the Department of Surgery, Nara Medical University. Among them, 7 patients (4.0%) were UN. We retrospectively evaluated the influence of the UN status on the postoperative complications.

Results:

The rate of acute kidney injury in the UN group was significantly higher than that in the control group (28.6% versus 1.2%; P = 0.017). In addition, the rates of surgical site infection of the organ/space (57.1% versus 9.0%; P = 0.006) and sepsis (42.9% versus 3.5%; P = 0.003) in UN group were significantly higher. Even on a reanalysis of only patients with soft pancreas, the significance remained.

Conclusions:

The UN status has a significant impact on the rate of morbidities, such as acute kidney injury and various infectious complications, including surgical site infections of organ/space, sepsis, and cholangitis after PD. Appropriate intervention should be implemented to decrease the morbidity rate for UN 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.

Risk factors for and the prevention of acute kidney injury after abdominal surgery

Postoperative acute kidney injury in patients undergoing abdominal surgery is not rare and often results in bad outcomes for patients. The incidence of postoperative acute kidney injury is hard to evaluate reliably due to its non-unified definitions in different studies. Risk factors for acute kidney injury specific to abdominal surgery include preoperative renal insufficiency, intraabdominal hypertension, blood transfusion, bowel preparation, perioperative dehydration, contrast agent and nephrotoxic drug use. Among these, preoperative renal insufficiency is the strongest predictor of acute kidney injury. The peri-operative management of high-risk patients should include meticulous selection of fluid solutions. Balanced crystalloid solutions and albumin are generally thought to be relatively safe, while the safety of hydroxyethyl starch solutions has been controversial. The purpose of the present review is to discuss the current knowledge regarding postoperative acute kidney injury in abdominal surgical settings to help surgeons make better decisions concerning the peri-operative management.

Comparison of acute kidney injury between open and laparoscopic liver resection: Propensity score analysis

The inflammatory response has been shown to be a major contributor to acute kidney injury. Considering that laparoscopic surgery is beneficial in reducing the inflammatory response, we compared the incidence of postoperative acute kidney injury between laparoscopic liver resection and open liver resection. Among 1173 patients who underwent liver resection surgery, 222 of 926 patients who underwent open liver resection were matched with 222 of 247 patients who underwent laparoscopic liver resection, by using propensity score analysis. The incidence of postoperative acute kidney injury assessed according to the creatinine criteria of the Kidney Disease: Improving Global Outcomes definition was compared between those 1:1 matched groups. A total 77 (6.6%) cases of postoperative acute kidney injury occurred. Before matching, the incidence of acute kidney injury after laparoscopic liver resection was significantly lower than that after open liver resection [1.6% (4/247) vs. 7.9% (73/926), P < 0.001]. After 1:1 matching, the incidence of postoperative acute kidney injury was still significantly lower after laparoscopic liver resection than after open liver resection [1.8% (4/222) vs. 6.3% (14/222), P = 0.008; odds ratio 0.273, 95% confidence interval 0.088-0.842, P = 0.024]. The postoperative inflammatory marker was also lower in laparoscopic liver resection than in open liver resection in matched set data (white blood cell count 12.7 ± 4.0 × 103/μL vs. 14.9 ± 3.9 × 103/μL, P < 0.001). Our findings suggest that the laparoscopic technique, by decreasing the inflammatory response, may reduce the occurrence of postoperative acute kidney injury during liver resection surgery.

A new plasma biomarker enhance the clinical prediction of postoperative acute kidney injury in patients with hepatocellular carcinoma

BACKGROUND

The ratio of serum γ-glutamyl transferase (GGT) to alanine aminotransferase (ALT) (GGT/ALT) is a marker for evaluating effects to antivirotic treatment and a helpful predictive factor for the prognosis of Child-Pugh A hepatocellular carcinoma (HCC) patients after surgery. The relationship between the incidence of postoperative acute kidney injury (AKI) and preoperative GGT/ALT is studied in hepatectomized hepatitis B- or C- associated HCC patients.

METHODS

A total of 253 hepatitis B or C virus-related HCC patients undergoing hepatectomy between September 2012 and August 2016 at our hospital were included in the retrospective study. Serum ALT and GGT value were recorded, and the GGT/ALT was computed. AKI was defined that based on the "Kidney Disease Improving Global Outcomes (KDIGO) criteria".

RESULTS

AKI was observed in 22 (8.7%) patients. Mean GGT/ALT of patients with AKI was significantly higher than in those without it (6.0 vs 2.1, P<0.001). Multivariate analysis revealed an increase in GGT/ALT as an independent risk factor for AKI in hepatitis B- or C- associated HCC patients, particularly in patients with Barcelona Clinic Liver Cancer (BCLC) stage 0 or A staged HCC (odds ratio (OR) 1.400, P<0.001). Multivariate analysis showed that ALT (OR 0.966, P=0.044) was somewhat inversely associated with the incidence of AKI in hepatitis B- or C- associated HCC patients. The best cutoff point of GGT/ALT was 2.92. Multivariate analysis showed that preoperative GGT/ALT ≥2.92 predicted poor prognosis of postoperative AKI in patients with HCC after hepatectomy (odds ratio 17.697, P<0.001). After propensity score matching, preoperative GGT/ALT ≥2.92 remained an independent risk factor for AKI in HCC patients (OR 13.947, P=0.003).

CONCLUSIONS

The GGT/ALT of patients with AKI was significantly higher than those without it. Evaluation of GGT/ALT before surgery can be a helpful predictive tool for postoperative AKI in hepatitis B- or C- associated HCC patients undergoing hepatectomy, particularly in patients with BCLC stage 0 or A staged HCC. Hepatitis B- or C- associated HCC patients with low ALT especially within the normal range may have a high risk of AKI. However, the reason remains to be elucidated.

Risk factors for acute kidney injury after partial hepatectomy

AIM

To identify risk factors for the occurrence of acute kidney injury (AKI) in the postoperative period of partial hepatectomies.

METHODS

Retrospective analysis of 446 consecutive resections in 405 patients, analyzing clinical characteristics, preoperative laboratory data, intraoperative data, and postoperative laboratory data and clinical evolution. Adopting the International Club of Ascites criteria for the definition of AKI, potential predictors of AKI by logistic regression were identified.

RESULTS

Of the total 446 partial liver resections, postoperative AKI occurred in 80 cases (17.9%). Identified predictors of AKI were: Non-dialytic chronic kidney injury (CKI), biliary obstruction, the Model for End-Stage Liver Disease (MELD) score, the extent of hepatic resection, the occurrence of intraoperative hemodynamic instability, post-hepatectomy haemorrhage, and postoperative sepsis.

CONCLUSION

The MELD score, the presence of non-dialytic CKI and biliary obstruction in the preoperative period, and perioperative hemodynamics instability, bleeding, and sepsis are risk factors for the occurrence of AKI in patients that underwent partial hepatectomy.

Mesenchymal stem cells correct haemodynamic dysfunction associated with liver injury after extended resection in a pig model

In patients, acute kidney injury (AKI) is often due to haemodynamic impairment associated with hepatic decompensation following extended liver surgery. Mesenchymal stem cells (MSCs) supported tissue protection in a variety of acute and chronic diseases, and might hence ameliorate AKI induced by extended liver resection. Here, 70% liver resection was performed in male pigs. MSCs were infused through a central venous catheter and haemodynamic parameters as well as markers of acute kidney damage were monitored under intensive care conditions for 24 h post-surgery. Cytokine profiles were established to anticipate the MSCs’ potential mode of action. After extended liver resection, hyperdynamic circulation, associated with hyponatraemia, hyperkalaemia, an increase in serum aldosterone and low urine production developed. These signs of hepatorenal dysfunction and haemodynamic impairment were corrected by MSC treatment. MSCs elevated PDGF levels in the serum, possibly contributing to circulatory homeostasis. Another 14 cytokines were increased in the kidney, most of which are known to support tissue regeneration. In conclusion, MSCs supported kidney and liver function after extended liver resection. They probably acted through paracrine mechanisms improving haemodynamics and tissue homeostasis. They might thus provide a promising strategy to prevent acute kidney injury in the context of post-surgery acute liver failure.

Models predicting the risks of six life-threatening morbidities and bile leakage in 14,970 hepatectomy patients registered in the National Clinical Database of Japan

To construct a robust morbidity risk-prediction model based on a Japanese nationwide web-based database of patients who underwent liver surgery.Although liver resection has become safer, patient mortality and morbidity still occur. This study investigated postoperative morbidity risks in patients who underwent hepatectomy in Japan at institutions registered in the National Clinical Database.This analysis involved 14,970 patients who underwent hepatectomy of more than 1 section, except for left lateral sectionectomy, during 2011 and 2012 at 1192 hospitals in Japan. Patients were randomized into 2 subsets, with 80% of patients analyzed for model development and the remaining 20% for model validation.Rates of 90-day inhospital mortality and overall morbidity were 3.7% and 25.7%, respectively. Rates of surgical site infection and bile leakage were 9.0% and 8.0%, respectively, but these morbidities showed little association with mortality. Rates of nonsurgical complications, including postoperative transfusion over 5 units, unexpected intubation, renal failure, cardiac events, septic shock, and postoperative pneumonia, ranged from 0.2% to 2.6%. These complications were highly associated with mortality, suggesting they were life-threatening. Risk models for morbidity yielded high C-indices for transfusion of over 5 units (0.758), unplanned intubation (0.755), renal failure (0.80), cardiac events (0.779), septic shock (0.783), pneumonia (0.768), and bile leakage (0.676).Preoperative parameters/comorbidities can accurately predict life-threatening complications after hepatectomy. These models allow early identification of patients at risk of mortality and may be useful in deciding on surgical interventions and in improving surgical quality.

A Predictive Model for Assessing Surgery-Related Acute Kidney Injury Risk in Hypertensive Patients: A Retrospective Cohort Study

Background

Acute kidney injury (AKI) is a serious post-surgery complication; however, few preoperative risk models for AKI have been developed for hypertensive patients undergoing general surgery. Thus, in this study involving a large Chinese cohort, we developed and validated a risk model for surgery-related AKI using preoperative risk factors.

Methods and Findings

This retrospective cohort study included 24,451 hypertensive patients aged ≥18 years who underwent general surgery between 2007 and 2015. The endpoints for AKI classification utilized by the KDIGO (Kidney Disease: Improving Global Outcomes) system were assessed. The most discriminative predictor was selected using Fisher scores and was subsequently used to construct a stepwise multivariate logistic regression model, whose performance was evaluated via comparisons with models used in other published works using the net reclassification index (NRI) and integrated discrimination improvement (IDI) index.

Results

Surgery-related AKI developed in 1994 hospitalized patients (8.2%). The predictors identified by our Xiang-ya Model were age, gender, eGFR, NLR, pulmonary infection, prothrombin time, thrombin time, hemoglobin, uric acid, serum potassium, serum albumin, total cholesterol, and aspartate amino transferase. The area under the receiver-operating characteristic curve (AUC) for the validation set and cross validation set were 0.87 (95% CI 0.86–0.89) and (0.89; 95% CI 0.88–0.90), respectively, and was therefore similar to the AUC for the training set (0.89; 95% CI 0.88–0.90). The optimal cutoff value was 0.09. Our model outperformed that developed by Kate et al., which exhibited an NRI of 31.38% (95% CI 25.7%-37.1%) and an IDI of 8% (95% CI 5.52%-10.50%) for patients who underwent cardiac surgery (n = 2101).

Conclusions/Significance

We developed an AKI risk model based on preoperative risk factors and biomarkers that demonstrated good performance when predicting events in a large cohort of hypertensive patients who underwent general surgery.

Acute renal injury after partial hepatectomy

Currently, partial hepatectomy is the treatment of choice for a wide variety of liver and biliary conditions. Among the possible complications of partial hepatectomy, acute kidney injury (AKI) should be considered as an important cause of increased morbidity and postoperative mortality. Difficulties in the data analysis related to postoperative AKI after liver resections are mainly due to the multiplicity of factors to be considered in the surgical patients, moreover, there is no consensus of the exact definition of AKI after liver resection in the literature, which hampers comparison and analysis of the scarce data published on the subject. Despite this multiplicity of risk factors for postoperative AKI after partial hepatectomy, there are main factors that clearly contribute to its occurrence. First factor relates to large blood losses with renal hypoperfusion during the operation, second factor relates to the occurrence of post-hepatectomy liver failure with consequent distributive circulatory changes and hepatorenal syndrome. Eventually, patients can have more than one factor contributing to post-operative AKI, and frequently these combinations of acute insults can be aggravated by sepsis or exposure to nephrotoxic drugs.

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.