Perioperative Acute Kidney Injury: An Under-Recognized Problem

Implementation of enhanced recovery after surgery in patients undergoing radical cystectomy: A retrospective cohort study

BACKGROUND

To evaluate the feasibility and effect of implementing enhanced recovery after surgery (ERAS) in patients undergoing radical cystectomy (RC) and urinary diversion.

MATERIALS AND METHODS

Since October 2016, a 15-point ERAS protocol has been implemented for patients undergoing elective RC and urinary diversion at Fudan University Shanghai Cancer Center (FUSCC). We retrospectively assessed patients who underwent RC performed between January 2014 and June 2018. The effects of implanting ERAS for RC were validated.

RESULTS

A total of 443 patients were included. The ERAS and non-ERAS groups included 185 and 258 patients, respectively. There was no significant difference in the patients' demographic characteristics, operative variables, perioperative systemic inflammation-based scores or mortality rates. Compared with the non-ERAS group, our study showed decreases in intraoperative blood loss volumes and transfusion rates in the ERAS group. Patients in the ERAS group also had earlier times to tolerate a clean liquid diet intake, first ambulation and first flatus. The incidences of postoperative pneumonia, urine leakage, intestinal obstruction and deep venous thrombosis were also significantly lower in the ERAS group. The time to pelvic drainage tube removal and the length of stay (LOS) were significantly shorter in the ERAS group than in the non-ERAS group, and the ERAS group also had a significantly lower incidence of 30-day readmission.

CONCLUSIONS

The results of this study suggest that ERAS protocols can accelerate the rehabilitation of patients undergoing RC, reduce the incidence of postoperative complications, shorten the LOS, and are safe and feasible in the field of RC. This study provides experience from FUSCC to further optimize ERAS protocols for patients with bladder cancer.

Under-recognized post-stroke acute kidney injury: risk factors and relevance for stroke outcome of a frequent comorbidity

BACKGROUND

Acute kidney injury (AKI) is emerging as a predictor of poor stroke outcome, however, it is often not recognized. The aim of our study was to evaluate post-stroke AKI burden, AKI risk factors and their influence in post-stroke outcome.

METHODS

From 2013 to 2016, 440 individuals with stroke diagnosis admitted in Stroke Unit, Foundation IRCCS Policlinico San Matteo (Pavia, Italy), were retrospectively enrolled. AKI cases identified by KDIGO criteria through the electronic database and hospital chart review were compared with the ones reported in discharge letters or in administrative hospital data base. Mortality data were provided by Agenzia Tutela della Salute of Pavia.

RESULTS

We included 430 patients in the analysis. Median follow-up was 19.2 months. We identified 79 AKI cases (18% of the enrolled patients, 92% classified as AKI stage 1), a fivefold higher number of cases than the ones reported at discharge. 37 patients had AKI at the admission in the hospital, while 42 developed AKI during the hospitalization. Cardioembolic (p = 0.01) and hemorrhagic (p = 0.01) stroke types were associated with higher AKI risk. Admission National Institutes of Health Stroke Scale (NIHSS, p < 0.05) and Charlson Comorbidity Index (p < 0.01) were independently associated with overall AKI, while admission NIHSS (p < 0.05) and eGFR (p < 0.005) were independently associated with AKI developed during the hospitalization. AKI was associated to longer in-hospital stay (p = 0.01), worse Rankin Neurologic Disability Score at discharge (p < 0.0001) and discharge disposition other than home (p = 0.03). AKI was also independently associated to higher in-hospital mortality (OR 3.9 95% CI 1.2-12.9 p = 0.023) but not with long-term survival.

CONCLUSIONS

Post-stroke AKI diagnosis needs to be improved by strictly monitoring individuals with cardioembolic or hemorrhagic stroke, reduced kidney function, higher Charlson Comorbidity Index and worse NIHSS at presentation.

Mannitol for the Prevention of Peri-Operative Acute Kidney Injury: A Systematic Review

OBJECTIVE/BACKGROUND

Post-operative acute kidney injury (AKI) is a frequent peri-operative complication that negatively affects morbidity and mortality. Mannitol is frequently used peri-operatively for renal protection, although evidence for its use is ambiguous. A systematic review was conducted to clarify whether there is evidence supporting peri-operative mannitol administration for the prevention of post-operative AKI.

METHODS

A systematic literature search was performed in MEDLINE/Pubmed, Embase, the Cochrane Library, Clinical Trials registry, and the Cochrane Central Register of Controlled Trials (CENTRAL). Eligibility criteria were (i) population (studies involving adult patients undergoing surgery or a related intervention); (ii) intervention (intravenous mannitol administered in either the pre- or intra-operative period with comparison to controls); and (iii) predefined outcomes (post-operative AKI or respective renal end points/surrogates).

RESULTS

In total, 1,538 articles published between January 1990 and October 2018 were identified. After checking for eligibility, 22 studies, including 17 prospective and/or randomised controlled trials and five retrospective studies, were included. The investigations involved various fields of surgery, such as aortic surgery, cardiac surgery with cardiopulmonary bypass, and urological procedures, including partial nephrectomy. Significant heterogeneity, limited sample size, and mostly short follow up periods were noted.

CONCLUSION

Given the available evidence, the peri-operative use of mannitol to prevent AKI cannot be considered an evidence based intervention in cardiac surgery, partial nephrectomy, and/or other major surgery. Further research is required with a focus on patients at high risk of post-operative AKI.

EZH2 plays a crucial role in ischemia/reperfusion-induced acute kidney injury by regulating p38 signaling

OBJECTIVE AND DESIGN

Renal ischemia-reperfusion (IR)-induced acute kidney injury (AKI) remains a major challenge in clinic. The histone methyltransferases enhancer of zest homolog-2 (EZH2) is associated with the development of renal injury. However, the molecular mechanism has not been fully elucidated.

MATERIALS

AKI in C57BL/6 mice was generated by renal IR.

TREATMENTS

The 3-deazaneplanocin A (DZNeP), a selective EZH2 inhibitor, or vehicle was administrated in mice after IR. HK-2 cells were exposed to hypoxia-reoxygenation (H/R) stress.

METHODS

Apoptosis was detected by TUNEL assay or flow cytometry. EZH2, caspase-3, p38, F4/80⁺ macrophages, and CD3⁺ T cells were examined by immunohistochemistry or Western blot. Tumor necrosis factor (TNF)-α, monocyte chemoattractant protein (MCP)-1, IL-6, and IL-18 were measured using RT-PCR.

RESULTS

Mice treated with DZNeP exhibited less severe renal dysfunction and tubular injury following IR. EZH2 inhibition decreased apoptotic cells while reducing activation of caspase-3 in kidneys under IR condition. Moreover, EZH2 inhibition impaired the recruitment of CD3⁺ T cells and F4/80⁺ cells in kidneys with IR. Administration of DZNeP suppressed the production of TNF-α, MCP-1, IL-6, and IL-18 in IR-treated kidneys. Of note, EZH2 inhibition reduced p38 phosphorylation in kidneys after IR. In H/R-treated HK-2 cells, DZNeP treatment or EZH2 knockdown reduced apoptosis. EZH2 inhibition inactivated p38 resulting in reduction of active caspase-3 and proinflammatory molecules. By contrast, EZH2 overexpression induced p38 phosphorylation, caspase-3 activation, and production of proinflammatory molecules, which was reversed by SB203580.

CONCLUSIONS

EZH2 plays a crucial role in IR-induced AKI via modulation of p38 signaling. Targeting EZH2/p38 signaling pathway may offer novel strategies to protect kidneys from acute kidney injury induced by ischemia-reperfusion.

Latent class analysis stratifies mortality risk in patients developing acute kidney injury after high-risk intraabdominal general surgery: a historical cohort study

PURPOSE

Risk stratification for postoperative acute kidney injury (AKI) evaluates a patient's risk for developing this complication using preoperative characteristics. Nevertheless, it is unclear if these characteristics are also associated with mortality in patients who actually develop this complication, so we aimed to determine these associations.

METHODS

The 2011-15 American College of Surgeons National Surgical Quality Improvement Program was used to obtain a historical, observational cohort of high-risk intraabdominal general surgery patients with AKI, which was defined as an increase in serum creatinine > 177 µmol·L-1 (2 mg·dL-1) above the preoperative value and/or the need for dialysis. Latent class analysis, a model-based clustering technique, classified patients based on preoperative comorbidities and risk factors. The associations between the latent classes and the time course of AKI development and mortality after AKI were assessed with the Kruskall-Wallis test and Cox models.

RESULTS

A seven-class model was fit on 3,939 observations (derivation cohort). Two patterns for the time course of AKI diagnosis emerged: an "early" group (median [interquartile range] day of diagnosis 3 [1-10]) and a "late" group (day 9 [3-16]). Three patterns of survival after AKI diagnosis were identified (groups A-C). Compared with the group with the lowest mortality risk (group A), the hazard ratios (95% confidence intervals) for 30-day mortality were 1.79 [1.55 to 2.08] for group B and 3.55 [3.06 to 4.13] for group C. These differences in relative hazard were similar after adjusting for the postoperative day of AKI diagnosis and surgical procedure category.

CONCLUSIONS

Among patients with AKI after high-risk general surgery, the preoperative comorbid state is associated with the time course of and survival after AKI. This knowledge can stratify mortality risk in patients who develop postoperative AKI.

Intraoperative Oliguria with Decreased SvO₂ Predicts Acute Kidney Injury after Living Donor Liver Transplantation

Acute kidney injury (AKI) is a frequent complication after living donor liver transplantation (LDLT), and is associated with increased mortality. However, the association between intraoperative oliguria and the risk of AKI remains uncertain for LDLT. We sought to determine the association between intraoperative oliguria alone and oliguria coupled with hemodynamic derangement and the risk of AKI after LDLT. We evaluated the hemodynamic variables, including mean arterial pressure, cardiac index, and mixed venous oxygen saturation (SvO₂). We reviewed 583 adult patients without baseline renal dysfunction and who did not receive hydroxyethyl starch during surgery. AKI was defined using the Kidney Disease Improving Global Outcomes criteria according to the serum creatinine criteria. Multivariable logistic regression analysis was performed with and without oliguria and oliguria coupled with a decrease in SvO₂. The performance was compared with respect to the area under the receiver operating characteristic curve (AUC). Intraoperative oliguria <0.5 and <0.3 mL/kg/h were significantly associated with the risk of AKI; however, their performance in predicting AKI was poor. The AUC of single predictors increased significantly when oliguria was combined with decreased SvO₂ (AUC 0.72; 95% confidence interval (CI) 0.68–0.75 vs. AUC of oliguria alone 0.61; 95% CI 0.56–0.61; p < 0.0001; vs. AUC of SvO₂ alone 0.66; 95% CI 0.61–0.70; p < 0.0001). Addition of oliguria coupled with SvO₂ reduction also increased the AUC of multivariable prediction (AUC 0.87; 95% CI 0.84–0.90 vs. AUC with oliguria 0.73; 95% CI 0.69–0.77; p < 0.0001; vs. AUC with neither oliguria nor SvO₂ reduction 0.68; 95% CI 0.64–0.72; p < 0.0001). Intraoperative oliguria coupled with a decrease in SvO₂ may suggest the risk of AKI after LDLT more reliably than oliguria alone or decrease in SvO₂ alone. Intraoperative oliguria should be interpreted in conjunction with SvO₂ to predict AKI in patients with normal preoperative renal function and who did not receive hydroxyethyl starch during surgery.

Effect of intraoperative dexmedetomidine on renal function after cytoreductive surgery and hyperthermic intraperitoneal chemotherapy: a randomized, placebo-controlled trial

INTRODUCTION

Cytoreductive surgery (CRS) and hyperthermic intraperitoneal chemotherapy (HIPEC) predispose to postoperative renal dysfunction. Dexmedetomidine is an α₂ adrenoreceptor agonist, which has renoprotective effects after cardiac surgery.

OBJECTIVE

To assess the effect of dexmedetomidine on renal function after CRS and HIPEC.

MATERIALS

Thirty-eight patients undergoing CRS and HIPEC were randomized to receive dexmedetomidine (dexmedetomidine group, n = 19, loading 1 μg/kg over 20 min followed by infusion at 0.5 μg/kg/h) or 0.9% sodium chloride (control group, n = 19) during surgery. Creatinine clearance (CrCl) was assessed daily until postoperative day 7. Urine neutrophil gelatinase-associated lipocalin (NGAL) and kidney injury molecule (KIM)-1 were measured for 24 h after surgery.

RESULTS

There was no difference in the lowest CrCl value during the first 7 days postoperatively, but the % change from baseline to the lowest value was lower in the dexmedetomidine group than in the control group (p = .037). Urine NGAL and KIM-1 levels were increased over time in both groups, but the increases were significantly less in the dexmedetomidine group (p = .018 and 0.038, respectively). In the dexmedetomidine group, the length of intensive care unit stay was shorter (p = .034).

CONCLUSIONS

Intraoperative dexmedetomidine infusion did not improve renal function in terms of serum Cr-related indices following CRS and HIPEC. However, as the decrease in CrCl was attenuated and early tubular-injury markers were lower in the dexmedetomidine group, dexmedetomidine may have protective effects against early tubular injury in CRS and HIPEC. Clinical Trials Registry: http://clinicaltrials.gov (NCT02641938).

Acute kidney injury following implementation of an enhanced recovery after surgery (ERAS) protocol in colorectal surgery

PURPOSE

Fluid management within Enhanced Recovery After Surgery (ERAS) protocols is designed to maintain a euvolemic state avoiding the negative sequelae of hypervolemia or hypovolemia. We sought to determine the effect of a recent ERAS protocol implementation on kidney function and on the incidence of postoperative acute kidney injury (AKI).

METHODS

A total of 132 elective colorectal resections performed using our ERAS protocol were compared to a propensity-matched group prior to ERAS implementation. Fluid balance, urine output, creatinine, and blood urea nitrogen (BUN) were recorded for all patients, and the incidence of AKI was determined according to the Kidney Disease Improving Global Outcomes (KDIGO) criteria.

RESULTS

Implementation of our ERAS protocol decreased average postoperative length of hospital stay (5.5 vs 7.7 days, p < 0.0001) and time to return of bowel function (2.5 vs 4.1 days, p < 0.0001). The rate of postoperative AKI increased following implementation of the protocol (11.4 vs 2.3%, p < 0.0001). However, by the time of discharge, the average creatinine of ERAS patients who had experienced AKI had returned to their preoperative baseline values (p = 0.9037). Significant univariate predictors of AKI in ERAS patients were longer operative times (p < 0.01) and the diagnosis of diverticulitis (p < 0.01). Within our ERAS patients, AKI was associated with a prolonged postoperative length of hospital stay (p < 0.01).

CONCLUSIONS

Despite the proven benefits of the Enhanced Recovery After Surgery (ERAS) protocols, care should be taken during protocol implementation to monitor for and to prevent acute kidney injury.

Acute Kidney Injury in the Age of Enhanced Recovery Protocols

BACKGROUND

Acute kidney injury is a prevalent complication after abdominal surgery. With increasing adoption of enhanced recovery protocols, concern exists for concomitant increase in acute kidney injury.

OBJECTIVE

This study evaluated effects of enhanced recovery on acute kidney injury through identification of risk factors.

DESIGN

This was a retrospective cohort study comparing acute kidney injury rates before and after implementation of enhanced recovery protocol.

SETTINGS

The study was conducted at a large academic medical center.

PATIENTS

All of the patients undergoing elective colorectal surgery between 2010 and 2016, excluding patients with stage 5 chronic kidney disease, were included.

MAIN OUTCOME MEASURES

Patients before and after enhanced recovery implementation were compared, with rate of acute kidney injury as the primary outcome. Acute kidney injury was defined as a rise in serum creatinine ≥1.5 times baseline within 30 days of surgery. Multivariable logistic regression identified risk factors for acute kidney injury.

RESULTS

A total of 900 cases were identified, including 461 before and 439 after enhanced recovery; 114 cases were complicated by acute kidney injury, including 11.93% of patients before and 13.44% after implementation of enhanced recovery (p = 0.50). Five patients required hemodialysis, with 2 cases after protocol implementation. Multivariable logistic regression identified hypertension, functional status, ureteral stents, nonsteroidal anti-inflammatory drugs, operative time >200 minutes, and increased intravenous fluid administration on postoperative day 1 as predictors of acute kidney injury. Laparoscopic surgery decreased the risk of acute kidney injury. The enhanced recovery protocol was not independently associated with acute kidney injury.

LIMITATIONS

The study was limited by its retrospective and nonrandomized before-and-after design.

CONCLUSIONS

No difference in rates of acute kidney injury was detected before and after implementation of a colorectal enhanced recovery protocol. Independent predictors of acute kidney injury were identified and could be used to alter the protocol in high-risk patients. Future study is needed to determine whether protocol modifications will further decrease rates of acute kidney injury in this population. See Video Abstract at http://links.lww.com/DCR/A568.

Inhibition of IL-18 reduces renal fibrosis after ischemia-reperfusion

Acute kidney injury induced by ischemia-reperfusion injury (IRI) is a high risk factor in the progression towards chronic kidney disease, which is featured by renal interstitial fibrosis. Interleukin (IL)-18 is produced by T cells and macrophages and has been involved in the pathophysiology of IRI. However, the role of IL-18 in IRI-induced renal fibrosis is poorly understood. In the present study, we showed that interleukin (IL)-18 was significantly up-regulated after IRI stress. Mice treated with IL-18 Bp, a natural inhibitor of IL-18, presented less severe fibrotic response in the kidneys following IRI compared with vehicle-treated mice. Inhibition of IL-18 decreased myofibroblasts formation in the kidneys in response to IRI, which was associated with reduction of fibronectin and collagenⅠproteins. Moreover, inhibition of IL-18 impaired infiltration of CD3⁺ T cells and F4/80⁺ macrophages in the kidneys of mice after IRI. Treatment with IL-18 Bp reduces the levels of profibrotic molecules in the kidneys of mice following IRI. Finally, administration of IL-18 Bp impedes the transition of M2 macrophages to myofibroblasts and suppressed the accumulation of bone marrow-derived M2 macrophages. Adoptive transfer of M2 macrophages abolished the anti-fibrotic effect of IL-18 Bp. In summary, our results suggest that IL-18 plays an important role in the progression of IRI-induced renal fibrosis via modulating inflammation cells infiltration, the expression of inflammatory cytokines and chemokines, and the transition of bone marrow-derived M2 macrophages to myofibroblasts.

HIF stabilization inhibits renal epithelial cell migration and is associated with cytoskeletal alterations

Acute kidney injury (AKI) is a common and potentially lethal complication in the hospitalized patients, with hypoxic injury being as a major cause. The loss of renal tubular epithelial cells (TEC), one of the AKI hallmarks, is potentially followed by tubular regeneration process orchestrated by the remaining uninjured TECs that undergo proliferation and migration. In this study, we used human primary TEC to investigate the initiation of tubular cell migration and associated cytoskeletal alterations in response to pharmacological HIF stabilization which resembles the pathophysiology of hypoxia. Tubular cells have been shown to migrate as cohorts in a wound healing assay. Importantly, cells of distal tubular origin moved faster than those of proximal origin. HIF stabilization impaired TEC migration, which was confirmed by live single cell tracking. HIF stabilization significantly reduced tubular cell migration velocity and promoted cell spreading. In contrast to the control conditions, HIF stabilization induced actin filaments rearrangement and cell adhesion molecules including paxillin and focal adhesion kinase. Condensed bundling of keratin fibers was also observed, while the expression of different types of keratins, phosphorylation of keratin 18, and the microtubule structure were not altered. In summary, HIF stabilization reduced the ability of renal tubular cells to migrate and led to cytoskeleton reorganization. Our data suggested an important involvement of HIF stabilization during the epithelial migration underlying the mechanism of renal regeneration in response to AKI.