Greater Risk Of Acute Kidney Injury Research Articles

Obesity is associated with acute kidney injury in ST-segment-elevation myocardial infarction undergoing percutaneous coronary intervention: A national representative cohort study.

Acute kidney injury (AKI) is a frequent and potentially life-threatening complication after percutaneous coronary intervention (PCI) in patients with ST-segment-elevation myocardial infarction (STEMI). However, the relationship between obesity and the risk of AKI in this specific patient population has not been previously examined. We queried the National Inpatient Sample (2016-2019) using ICD-10 codes to obtain a sample of adults with STEMI undergoing PCI. All patients were further subcategorized into obese and nonobese cohorts. The primary outcome was the incidence of AKI. Multivariate regression analysis was performed to assess the impact of obesity on AKI. The consistency of this correlation between subgroups was investigated using subgroup analysis and interaction testing. A total of 62,599 (weighted national estimate of 529,016) patients were identified, of which 9.80% (n = 6137) had AKI. Obesity comprised 19.78% (n = 1214) of the AKI cohort. Obese patients were on average younger, male, white, and had more comorbidities. Additionally, there was a significant positive association between obesity and AKI incidence (adjusted odds ratio [aOR]: 1.24, 95% confidence interval [CI]: 1.15-1.34), which was more pronounced in female patients (aOR: 1.56, 95% CI: 1.33-1.82, p < 0.001, p-interaction = 0.008). The AKI incidence in these patients increased steadily during the 4-year study period, and it was consistently higher in obese patients than in nonobese patients (p-trend < 0.001 for all). Obesity was independently associated with a greater risk of AKI among adults with STEMI undergoing PCI, particularly in female patients.

National clinical and financial outcomes associated with acute kidney injury following esophagectomy for cancer.

Esophagectomy is a complex oncologic operation associated with high rates of postoperative complications. While respiratory and septic complications have been well-defined, the implications of acute kidney injury (AKI) remain unclear. Using a nationally representative database, we aimed to characterize the association of AKI with mortality, resource use, and 30-day readmission. All adults undergoing elective esophagectomy with a diagnosis of esophageal or gastric cancer were identified in the 2010-2019 Nationwide Readmissions Database. Study cohorts were stratified based on presence of AKI. Multivariable regressions and Royston-Parmar survival analysis were used to evaluate the independent association between AKI and outcomes of interest. Of an estimated 40,438 patients, 3,210 (7.9%) developed AKI. Over the 10-year study period, the incidence of AKI increased from 6.4% to 9.7%. Prior radiation/chemotherapy and minimally invasive operations were associated with reduced odds of AKI, whereas public insurance coverage and concurrent infectious and respiratory complications had greater risk of AKI. After risk adjustment, AKI remained independently associated with greater odds of in-hospital mortality (AOR: 4.59, 95% CI: 3.62-5.83) and had significantly increased attributable costs ($112,000 vs $54,000) and length of stay (25.7 vs 13.3 days) compared to patients without AKI. Furthermore, AKI demonstrated significantly increased hazard of 30-day readmission (hazard ratio: 1.16, 95% CI: 1.01-1.32). AKI after esophagectomy is associated with greater risk of mortality, hospitalization costs, and 30-day readmission. Given the significant adverse consequences of AKI, careful perioperative management to mitigate this complication may improve quality of esophageal surgical care at the national level.

Metformin use is associated with reduced acute kidney injury following coronary artery bypass grafting in patients with type 2 diabetes: An inverse probability of treatment weighting analysis.

Acute kidney injury (AKI) is a common and serious complication after coronary artery bypass grafting (CABG) surgery. Patients with diabetes are commonly associated with renal microvascular complications and have a greater risk of AKI after CABG surgery. This study aimed to explore whether preoperative metformin administration could reduce the incidence of postoperative AKI following CABG in patients with type 2 diabetes. Patients were retrospectively enrolled in this study between January 2019 and December 2020. AKI after CABG was defined according to the Kidney Disease Improving Global Outcomes (KDIGO) criteria. Inverse probability of treatment weighting (IPTW) was applied to minimize baseline differences between the two groups. IPT-weighted P values were analyzed to evaluate the postoperative outcomes between the two groups. A total of 812 patients were enrolled. The patients were divided into the metformin group (203 cases) and the control group (609 cases) according to whether metformin was used preoperatively. After IPTW adjustment, the incidence of AKI in the metformin group was lower than the control group (IPTW-adjusted P < 0.001). In the subgroup analysis, metformin showed significant protective effects in the estimated glomerular filtration rate (eGFR) < 60 mL/min per 1.73 m2 and eGFR 60-90 mL/min per 1.73 m2 subgroups, which was not observed in the eGFR ≥90 mL/min per 1.73 m2 subgroup. No significant differences in the incidence of renal replacement therapy, reoperation due to bleeding, in-hospital mortality, or red blood cell transfusion volume were observed between the two groups. In this study, we provided evidence that preoperative metformin was associated with a significant reduction of postoperative AKI following CABG in patients with diabetes. Metformin showed significant protective effects in patients with mild to moderate renal insufficiency.

Greater renal interstitial expansion and inflammation in older male versus older female rats following a four-day simulated heatwave

Acute kidney injury (AKI) is an emerging cause of morbidity during heatwaves worldwide and is associated with negative health outcomes. Older age increases the likelihood of AKI, which is a top cause of hospitalization during heatwaves in older adults. Further, biological sex likely affects the severity of, and prognosis following, AKI. Moreover, recent observations suggest that older women are at greater risk of AKI during heatwaves compared to older men. Whether this observation can be directly attributed to biological sex is unclear. Therefore, we tested the hypothesis that older female rats experience more severe kidney injury during a four-day simulated heatwave, compared to older male rats.To test this hypothesis, older (18-22 month old) male (M) and female (F) Wistar rats were exposed to a 36°C (M: n=5; F: n=8) or a 21°C (M: n=2; F: n=2) environment for three hours over four consecutive days. During, and for five hours following heat exposure, the rats did not have access to food or water, but otherwise were housed in standard housing conditions with free access to food and water. Core temperature (Tc) was continuously monitored and rats were removed from the heat if Tc reached 40.5℃, a safeguard put in place to prevent heatstroke. Data are presented as mean±SD.Male and females did not differ in the amount of time exposed to heat during each day (average duration - M: 39.3±4.0, F: 42.3±5.2 minutes, P=0.86) or body weight loss during heat exposure (average body weight loss - M: -2.0±0.1, F: -2.5±0.1% P=0.93). Serum creatinine concentration did not differ between heat exposed males and females on Day 1 (pre- M: 0.4±0.2, F: 0.4±0.1; post- M: 0.5±0.2, F: 0.4±0.2 mg/dL) or Day 4 (post- M: 0.4±0.1, F:0.3±0.1 mg/dL; P=0.86) Heat exposure resulted in cortical interstitial expansion and immune cell infiltration in aged male, but not female rats (M Heat: 77.2±36.1, F Heat: 12.1±16.5, M Control: 18.2±17.5, F Control: 13.4±19.0 dots per image, P=0.002). Only older male rats displayed greater interstitial immune cell infiltration than older controls in response to heating (P=0.04). Immunohistochemistry demonstrated distinct populations of CD3e+ T cells, CD20+ B cells and CD68+ macrophages within the interstitial immune cell infiltration in the older male rats. Kidney expression of kidney injury molecule 1 (KIM1, P=0.41) and neutrophil gelatinase associated lipocalin (NGAL, P=0.12) did not differ between older male and female rats exposed to heat or control conditions. Compared to older female rats, older male rats display increased cortical interstitial expansion and inflammation following a four-day simulated heatwave. UL1TR002529, T32DK120524 This is the full abstract presented at the American Physiology Summit 2023 meeting and is only available in HTML format. There are no additional versions or additional content available for this abstract. Physiology was not involved in the peer review process.

Candidates for area under the concentration–time curve (AUC)-guided dosing and risk reduction based on analyses of risk factors associated with nephrotoxicity in vancomycin-treated patients

Compared with vancomycin trough concentration (Cmin)-guided dosing, area under the concentration-time curve (AUC)-guided dosing is associated with decreased acute kidney injury (AKI). However, whether Cmin-guided or AUC-guided dosing should be used in patients other than those with serious MRSA infections remains uncertain. The purposes of this multicentre study were to identify risk factors for early- and late-phase vancomycin-induced AKI and to identify candidates for AUC-guided dosing, rather than Cmin-guided dosing, who require a more accurate dose titration to reduce the AKI risk. A multivariate logistic regression analysis was applied to identify risk factors for AKI. Additionally, the cut‑off day for AKI onset, cut-off Cmin for AKI, safe Cmin for reduced AKI risk and probability of AKI were calculated. In total, 8.4% (159/1882) of patients developed AKI. AKI occurred within the first 7 days of therapy (early phase) in the vast majority of patients. Significant risk factors for AKI during the early phase were identified as Cmin > 20 mg/L, ICU stay, concurrent diuretic or piperacillin/tazobactam use, and pre-existing renal dysfunction. A temporarily elevated Cmin (>15-20 mg/L) was not associated with a greater risk of AKI. In patients with risk factors, the cut-off Cmin for AKI and the estimated safe Cmin for reduced AKI risk were 18.8-21.0 mg/L and <11.7-13.5 mg/L, respectively. Patients with known AKI risk factors require a low target Cmin. The presence of several risk factors for AKI may indicate a need for more accurate dose titration using AUC-guided dosing.

Epidemiology of hospitalizations due to pesticide intoxication-associated acute kidney injury in China

BackgroundThere is a paucity of epidemiological data regarding pesticide intoxication-associated acute kidney injury (AKI). Therefore, the aim of this study was to identify the epidemiological features, risk factors, and adverse outcomes of AKI in this population.MethodsThe data used in this multi-center, hospitalized population-based, retrospective study were retrieved from electronic medical records. AKI was defined as an acute increase in serum creatinine according to the criteria of Kidney Disease: Improving Global Outcomes. The Charlson Comorbidity Index was used to evaluate the burden of in-hospital mortality.ResultsOf 3,371 adult patients in 11 hospitals, 398 (11.8%) were diagnosed with AKI (grade 1, 218 [6.5%]; grade 2, 89 [2.6%]; grade 3, 91 [2.7%]). Herbicide intoxication was associated with the highest incidence of AKI (53.5%) and higher grades of AKI. After multivariable adjustment, pesticide categories and moderate or severe renal disease were independently associated with AKI. As compared with the referred category, insecticide and herbicide intoxications were associated with a 1.3-fold (95% CI 1.688–3.245) and 3.8-fold (95% CI 3.537–6.586) greater risk of AKI. Regardless of the pesticide category, AKI was independently associated with in-hospital mortality, with odds ratios of 3.433 (95% CI 1.436–8.203) for insecticides, 2.153 (95% CI 1.377–3.367) for herbicides, and 4.524 (95% CI 1.230–16.632) for unclassified or other pesticides.ConclusionAKI is common in pesticide intoxication and associated with an increased in-hospital mortality. Herbicides pose the greatest risks of AKI and death.

Renal adverse effects of immune checkpoints inhibitors in clinical practice: ImmuNoTox study

Background/objectivesAcute Kidney Injury (AKI), induced by Checkpoint Inhibitors therapies (CPI-induced AKI), is an uncommon but severe Immune-Related Adverse Event (IRAE). The aim was to describe the epidemiology, risks factors, clinical, and laboratory characteristics of these renal adverse events (AEs) in a real-life cohort treatment. Design/participantsConsecutive patients undergoing a checkpoint inhibitor (CPI) therapy at the Hôpital Lyon Sud from January 2015 to July 2017 were included. A systematic retrospective analysis of medical files was performed, monthly serum creatinine levels, associated treatments, and occurrence of other IRAEs data were collected. AKI episodes explained by classic AKI aetiologies (prerenal, obstructive, septic) were excluded from the analysis. ResultsCPI-induced AKI incidence was 3.7% (13/352) and appeared to be time-dependent (7.7% (11/143) for patients with >3 months of CPI exposure), ranging from 1 to 16 months. All cases with available histology were acute tubulointerstitial nephritis (ATIN), with poor urinary sediment. The severity of AKI was mild (stage 1 in 50% of cases), with no need for renal-replacement therapy. Although CPI-induced AKI patients had more frequently other IRAEs (77% versus 39%), this was not associated with a greater risk of AKI. Pre-existing chronic kidney disease (defined as an estimated glomerular filtration rate (eGFR) <60 ml/min) was not associated with a greater risk of CPI-induced AKI. Treatments of CPI-induced AKI were heterogeneous, with discontinuation of CPIs, and inconstant systemic corticosteroid therapy. ConclusionThe monitoring of renal function and early identification of AKI during CPIs treatment is essential. The optimal management of CPI-induced AKI remains unclear and requires a close collaboration between the oncology and nephrology departments. Clinical relevancy statementImmune checkpoint inhibitors (CPIs) have dramatically improved patient outcomes in different malignant contexts such as melanoma, non-small cell lung cancers (NSCLC) and urologic cancers. Usually well-tolerated, CPIs are however associated with immune-related adverse events (IRAEs). Among them, acute kidney injury (AKI) is uncommon, and not well-described. Following the exponential increase in the prescription of CPIs, previously uncommon cases of IRAEs (such as AKI) have become common occurrence in referral centres. Data regarding the epidemiology, risk factors, or management of CPI-induced AKI are currently lacking or can be discordant. Data regarding CPI-induced AKI, in a large real-life cohort were reported herein.

Risk factors for acute kidney injury after pharmacomechanical thrombolysis for acute deep vein thrombosis

BackgroundPharmacomechanical thrombolysis (PMT) is an established treatment for selected patients with acute deep vein thrombosis (DVT). Despite significant clinical success, hemolysis can lead to acute kidney injury (AKI) with unknown longer term implications. Our aim was to characterize the rate of AKI after PMT and identify those patients at the greatest risk. MethodsA retrospective medical record review of patients with acute DVT who had undergone PMT in our institution from 2007 to 2018 was performed. The baseline demographics, comorbidities, preoperative clinical characteristics, procedural details, postoperative hospital course, and follow-up data were reviewed. The primary outcome was postoperative AKI (≥1.5 times preoperative creatinine), and longer term renal impairment. Logistic regression modeling was used to identify associated factors. ResultsA total of 137 patients (mean age, 47 ± 16.6 years; 49.6% male) who had undergone PMT for treatment of acute DVT were identified (85.4% AngioJet system; Boston Scientific Corp, Marlborough, Mass). Of the 137 patients, 30 (21.9%) had developed AKI in the periprocedural period, 1 of whom had required hemodialysis in the perioperative period. The patients who had developed AKI had had significantly greater rates of preoperative coronary artery disease (23.1% vs 4.7%; P = .002), diabetes mellitus (19.2% vs 6.6%; P = .045), dyslipidemia (42.3% vs 17.9%; P = .008), and hypertension (53.6% vs 29.3%; P = .018). No significant difference was found in preoperative creatinine (0.99 vs 0.92 mg/dL; P = .65) or glomerular filtration rate (GFR; 96.9 vs 91.8 mL/min; P = .52) between the two groups. Multivariate analysis demonstrated bilateral DVT (odds ratio [OR], 4.35; 95% confidence interval [CI], 1.47-12.86; P = .008), single-session PMT (OR, 3.05; 95% CI, 1.02-9.11; P = .046), and female sex (OR, 2.85; 95% CI, 1.01-8.04; P = .048) were significant predictors of AKI. Of the 30 patients, 10 had had normal renal function at discharge and 15 and 25 patients had had normal renal function at the first and subsequent clinical follow-up visits, respectively. The remaining five patients (3.6%) had progressed to moderate (GFR, <60 mL/min) or severe (GFR, <30 mL/min) renal insufficiency, with one requiring long-term hemodialysis. ConclusionsThe use of PMT for treatment of acute DVT conferred a risk of AKI that will progress to chronic renal failure in a small fraction of affected patients. Patients with bilateral extensive DVTs have a greater risk of AKI; thus, longer priming with a thrombolytic drip before PMT should be preferred for this population.

Impact of Preemptive Leucovorin Dose Escalation on Incidence of Delayed Methotrexate Elimination in Lymphoma Patients Receiving High-Dose Methotrexate

Background: Prolonged methotrexate (MTX) exposure following high-dose methotrexate (HDMTX; ≥1g/m2) occurs in up to 33% of patients and potentially compromises management through increased renal and systemic toxicities.(Pinedo et al, 1977, Joerger et al, 2012) MTX-associated acute kidney injury (AKI) occurs in 5% to 30% of patients.(May et al, 2014) Rescue leucovorin dose escalation in response to an elevated 48-hour MTX concentration or serum creatinine rise is standard-of-care to reduce adverse events. The practice of preemptive leucovorin dose increases in patients with elevated MTX concentrations or previous AKI during prior MTX doses has unclear outcomes. Methods: This retrospective, single-center, cohort study was approved by the Mayo Clinic IRB and performed in accordance with the ethical standards of the 1964 Declaration of Helsinki. We identified patients newly initiated on HDMTX for management of lymphoma between 1/1/2011 and 10/31/2017 at Mayo Clinic in Rochester, MN. Patients were followed longitudinally until HDMTX was discontinued. The primary endpoint was the proportion of patients with an elevated MTX concentration (MTX &gt; 1.0 mcmol/L) at 48 hours for the initial cycle. Secondary endpoints included the incidence of AKI (Kellum et al, 2012) and whether preemptively increased leucovorin doses during subsequent cycles of HDMTX impacted the incidence of a repeated episode of an elevated 48-hour MTX concentration, decreased incidence of AKI, or decreased hospital length of stay (LOS) compared to patients with standard leucovorin dosing (25mg intravenous every 6 hours until MTX &lt; 0.1 mcmol/L). Results: The 321 included patients had a median (IQR) age of 65 (57, 72) years, 190 (59%) were male, and 293 (91%) were Caucasian. Baseline demographics and clinical characteristics are depicted in table 1 with those who had elevated MTX levels during their initial cycle more likely to be Male, Caucasian, have a higher BSA, have Primary DLBCL of the CNS, have bone marrow involvement, have a higher baseline SCr, higher total bilirubin, and lower albumin. The median (IQR) grams of the initial MTX dose was 6.3 (4.3, 7.5) for 84 patients (26%) receiving MTX for prophylaxis and was 12.8 grams (7.5, 16.8) for the 237 patients (74%) receiving MTX as treatment. Chemotherapy regimen distribution included 43 patients (13%) receiving HDMTX 8 grams/m2 monotherapy, 162 patients (50%) receiving HDMTX 8 grams/m2 with Rituximab and Temozolomide (MRT), and 96 patients (30%) receiving HDMTX 3.5 grams/m2 in combination with R-CHOP. Patients received a median of 3 MTX doses (IQR:2 doses, 6 doses). A total of 83 patients (36%) had an elevated MTX concentration after their first MTX dose, and the overall incidence of elevated MTX concentrations was 22% following a total of 1558 MTX doses. Preemptively increasing the leucovorin dose (based on the prior MTX concentration) was associated with a 34% rate of elevated MTX concentrations (160/466 cycles). Giving standard leucovorin (based on the prior MTX concentration) was associated with a 12% rate of elevated MTX concentration (84/713 cycles). Those with a preemptively increased leucovorin dose were more likely to have an elevated MTX concentration in that cycle (OR=2.84, 95% CI: 2.03-3.97, p&lt;0.001). For the secondary endpoint of AKI, the overall incidence was 18% with 107 patients (33%) experiencing AKI after their first MTX dose. In these first dose AKI episodes, 81 cases (25%) were stage 1, 19 (6%) stage 2, and 7 (2%) stage 3 Preemptive leucovorin dose increase was associated with a greater risk of AKI after MTX (OR=1.52, 95% CI: 1.05-2.19, p=0.027). Overall median hospital LOS was 4.1 (3.8, 5.8) days. Hospital LOS was longer in those with preemptively increased leucovorin doses (Median LOS with preemptively increased leucovorin doses: 5 (4.1, 6.1) days; without preemptively increased leucovorin doses: 4 (3.2, 4.3) days; estimated difference=1.1 days, 95% CI: 0.5-1.7, p&lt;0.001). Conclusion: HDMTX leads to a significant incidence of elevated serum 48hr MTX levels and AKI, 22% and 18%, respectively. Rather than protective, we found that preemptively increased leucovorin doses used during subsequent cycles did not improve the incidence of delayed elimination, reduce the incidence of AKI, or shorten hospital LOS per MTX dose. Further investigation is needed to optimize dosing strategies and supportive measures following MTX administration for management of lymphoma patients. Disclosures Barreto: FAST Biomedical, Inc: Consultancy. Leung:Takeda: Research Funding; Prothena: Membership on an entity's Board of Directors or advisory committees; Aduro: Membership on an entity's Board of Directors or advisory committees; Omeros: Research Funding.

Impact of Aortic Atherosclerosis Burden on Outcomes of Surgical Aortic Valve Replacement

Epiaortic ultrasound detects and localizes ascending aortic atherosclerosis. In this analysis we investigated the association between epiaortic ultrasound-based atheroma grade during surgical aortic valve replacement (SAVR) and perioperative adverse outcomes. SAVR patients in a randomized trial of 2 embolic protection devices underwent a protocol-defined 5-view epiaortic ultrasound read at a core laboratory. Aortic atherosclerosis was quantified with the Katz atheroma grade, and patients were categorized as mild (grade I-II) or moderate/severe (grade III-V). Multivariable logistic regression was used to estimate associations between atheroma grade and adverse outcomes, including death, clinically apparent stroke, cerebral infarction on diffusion-weighted magnetic resonance imaging, delirium, and acute kidney injury (AKI) by 7and 30 days. Precannulation epiaortic ultrasound data were available for 326 of 383 randomized patients (85.1%). Of these, 106 (32.5%) had moderate/severe Katz atheroma grade at any segment of the ascending aorta. Although differences in the composite of death, stroke, or cerebral infarction on diffusion-weighted magnetic resonance imaging by 7 days were not statistically significant, moderate/severe atheroma grade was associated with a greater risk of AKI by 7 days (adjusted odds ratio, 2.63; 95% confidence interval, 1.24-5.58; P= .01). At 30 days, patients with moderate/severe atheroma grade had a greater risk of death, stroke, or AKI (adjusted odds ratio, 1.97; 95% confidence interval, 1.04-3.71; P= .04). Moderate/severe aortic atherosclerosis was associated with an increased risk of adverse events after SAVR. Epiaortic ultrasound may serve as a useful adjunct for identifying patients who may benefit from strategies to reduce atheroembolic complications during SAVR.

What is the most important predictor of renal function after opened and robotic partial nephrectomy? A propensity score matched study.

701 Background: This study was designed to investigate the parameters that predict the short term and long term renal function after opened partial nephrectomy (OPN) and robot-assisted partial nephrectomy (RPN). Methods: Medical records of 896 patients who underwent OPN and RPN between Feb 2004 to Apr 2017 at our institution were retrospectively reviewed. The propensity scores matching between of OPN and RPN group were performed with a ratio of 1:1. Postoperative outcomes were compared and multivariate logistic regression was performed to identify the parameters influencing acute kidney injury (AKI) and chronic kidney disease (CKD) progression. Results: No significant differences of preoperative characteristics were observed between two study groups after propensity score matching. RPN was significantly associated with longer warm ischemic time (WIT) (p &lt; 0.001); yet, estimated blood loss (EBL), positive surgical margin (PSM) rate, major postoperative complication and CKD progression were significantly lower in RPN group (p values were &lt; 0.001; 0.033; &lt; 0.001; &lt; 0.001 and 0.005 respectively). Multivariate analysis exhibited RPN is more favorable than OPN in terms of preserving renal function. Patients with a higher baseline estimated glomerular filtration rate (eGFR) were significantly associated with greater risk of AKI (OR = 1.036; 95% CI of OR 1.021-1.052; p &lt; 0.001), but reduced risk of CKD progression (OR = 0.975; 95% CI of OR 0.955-0.994; p = 0.011). Other independent predictors of CKD progression included WIT (p = 0.025), age (p = 0.035), higher BMI (0.041) and diabetes mellitus history (p = 0.035). Conclusions: Age, BMI, diabetes mellitus history, baseline eGFR and WIT were the independent predictors of CKD progression after PN. RPN is more favorable than OPN for reducing EBL, PSM, major postoperative complication and renal function preservation.

Associations of fluid amount, type, and balance and acute kidney injury in patients undergoing major surgery.

Fluid administration has been reported to be associated with an increased risk of acute kidney injury (AKI). We assessed whether, after correction for fluid balance, amount and chloride content of fluids administered have an independent association with AKI. We performed an observational study in patients after major surgery assessing the independent association of AKI with volume, chloride content and fluid balance, after adjustment for Physiological and Operative Severity Score for enUmeration of Mortality and morbidity (POSSUM) score, age, elective versus emergency surgery, and duration of surgery. We studied 542 consecutive patients undergoing major surgery. Of these, 476 patients had renal function tested as part of routine clinical care and 53 patients (11.1%) developed postoperative AKI. After adjustments, a 100 ml greater mean daily fluid balance was artificially associated with a 5% decrease in the instantaneous hazard of AKI: adjusted Hazard Ratio (aHR) 0.951, 95% confidence intervals (CI) 0.935 to 0.967, <i>P</i> <0.001. However, after adjustment for the proportion of chloride-restrictive fluids, mean daily fluid amounts and balances, POSSUM morbidity, age, duration and emergency status of surgery, and the confounding effect of fluid balance, every 5% increase in the proportion of chloride-liberal fluid administered was associated with an 8% increase in the instantaneous hazard of AKI (aHR 1.079, 95% CI 1.032 to 1.128, <i>P</i>=0.001), and a 100 ml increase in mean daily fluid amount given was associated with a 6% increase in the instantaneous hazard of AKI (aHR 1.061, 95% CI 1.047 to 1.075, <i>P</i> <0.001). After adjusting for key risk factors and for the confounding effect of fluid balance, greater fluid administration and greater administration of chloride-rich fluid were associated with greater risk of AKI.

Intra‐Operative Urinary Hypoxia During Cardiac Surgery on Cardiopulmonary Bypass Predicts Later Development of Acute Kidney Injury

Renal medullary hypoxia may be a common pathway in the development of acute kidney injury (AKI). There are no validated methods to detect medullary hypoxia in patients. However, experimental findings indicate that changes in urinary oxygen tension (UPO2) reflect changes in medullary PO2. Therefore, we evaluated the relationship between intra‐operative UPO2 and the development of AKI after cardiac surgery requiring cardiopulmonary bypass (CPB). From January 2015 to July 2016, thirty‐five adult patients undergoing on‐pump cardiac surgery were prospectively enrolled. UPO2 was continuously recorded intra‐operatively via a fiber‐optic probe deployed through the lumen of the urinary catheter, with the end of the probe at the catheter tip, where it was in contact with bladder urine. UPO2 fell during surgery, particularly during CPB. The lowest (nadir) UPO2 was most frequently observed during the rewarming phase of CPB, or shortly after weaning from CPB (n=25, 71%). Fourteen patients (40%) developed AKI as defined by an increase in serum creatinine from baseline of either &gt; 26.5 μmol/L (0.3 mg/dL) within 48 hours or &gt; 50% within 5 days. Nadir intra‐operative UPO2 was lower in patients who later developed AKI (8.5 ± 1.6 mmHg, mean ± SE) than in those who did not (16.5 ± 4.2 mmHg, P = 0.02). UPO2 below 10 mmHg at any time during surgery was associated with a 4.5‐fold [95% confidence limits 1.6 – 19.1] greater risk of AKI (P = 0.03). Furthermore, urinary PO2 below 15 mmHg for longer than the median time for all patients (5.6 min per hour of surgery) was associated with a 7.3‐fold [1.8 – 35.1] greater risk of AKI (P = 0.01) and an area under the receiver operator curve of 0.73 [0.56 – 0.90] (P = 0.03). We conclude that low UPO2 during cardiac surgery requiring CPB is strongly associated with later development of AKI. Continuous intra‐operative monitoring of UPO2 is simple and relatively non‐invasive. It may provide a real‐time biomarker of risk of AKI. Early detection of risk of AKI may in‐turn provide a window of opportunity to intervene and thus avoid development of AKI in patients undergoing cardiac surgery.

Poor Cardiac Function is Associated With Renal Injury Following EVAR

Poor Cardiac Function is Associated With Renal Injury Following EVAR

Invited Commentary

Invited Commentary

Urinary hepcidin: an inverse biomarker of acute kidney injury after cardiopulmonary bypass?

In this review, we discuss the potential role of urinary hepcidin, a 2.8-kDa hormonal regulator of iron metabolism, as a biomarker of acute kidney injury (AKI) after cardiopulmonary bypass. Hepcidin is one of the novel biomarkers of AKI that have been identified using hypothesis-free, proteomic analysis of urine or plasma in patients who develop AKI. Collectively, these markers promise a new era for the early diagnosis and treatment of AKI in the ICU and an understanding of their biological role may also provide mechanistic insights into the pathogenesis of AKI. Although data confirming the association between urinary hepcidin and AKI are as yet limited, we believe hepcidin is of particular interest because hepcidin may be a biomarker specific to cardiopulmonary bypass-associated AKI; as a central regulator of iron metabolism, hepcidin could play a biological role in the pathogenesis of AKI after cardiopulmonary bypass; and hepcidin displays an intriguing negative association with AKI, in that a smaller increase in hepcidin from baseline after cardiopulmonary bypass appears to predict greater chance of developing AKI. Smaller increases in urinary hepcidin, a central regulator of iron metabolism, may be associated with greater risk of AKI after cardiopulmonary bypass. Further research is required to establish the significance and nature of this association.