Contrast-associated acute kidney injury: does it really exist, and if so, what to do about it?

Assessing the clinical utility of abdominal computed tomography in sepsis patients with unknown origin: A retrospective cohort study

Early identification of the sources of infection in emergency department (ED) patients of sepsis remains challenging. Computed tomography (CT) has the potential to identify sources of infection. This retrospective study aimed to investigate the role of CT in identifying sources of infection in patients with sepsis without obvious infection foci in the ED. A retrospective chart review was conducted on patients with fever and sepsis visiting the ED of Linkou Chang Gung Memorial Hospital between July 1, 2020 and June 30, 2021. Data on patient demographics, vital signs, clinical symptoms, underlying medical conditions, laboratory results, administered interventions, length of hospital stay, and mortality outcomes were collected and analyzed. Of 218 patients included in the study, 139 (63.8%) had positive CT findings. The most common sources of infection detected by CT included liver abscesses, acute pyelonephritis, and cholangitis. Laboratory results showed that patients with positive CT findings had higher white blood cell and absolute neutrophil counts and lower hemoglobin levels. Positive blood culture results were more common in patients with positive CT findings. Additionally, the length of hospital stay was longer in the group with positive CT findings. Multivariate logistic regression analysis revealed that hemoglobin levels and positive blood culture results independently predicted positive CT findings in patients with fever or sepsis without an obvious source of infection. In patients with sepsis with an undetermined infection focus, those presenting with leukocytosis, anemia, and elevated absolute neutrophil counts tended to have positive findings on abdominal CT scans. These patients had high rates of bacteremia and longer lengths of stay. Abdominal CT remains a valuable diagnostic tool for identifying infection sources in carefully selected patients with sepsis of undetermined infection origins.

Prevention of contrast-associated acute kidney injury in an era of increasingly complex interventional procedures

Radiological and interventional cardiology procedures are in continuous expansion, leading to an important increase in the incidence of contrast-associated acute kidney injury (CA-AKI). Although numerous methods of CA-AKI prevention have been studied, at present, there is no consensus on the definition of this entity or on its prevention. In this paper, we aim to provide a critical analysis of the existing data on the epidemiology, pathophysiology, and clinical significance of CA-AKI. Existing and emergent approaches for CA-AKI prevention are also discussed, with a focus on parenteral fluid administration and on the most recent clinical and experimental data. We also emphasize a number of questions that remain to be answered, and we identify hotspots for future research.

Clinical Characteristics and Outcomes of Drug-Induced Acute Kidney Injury Cases

Introduction

Drug-induced acute kidney injury (DI-AKI) is a frequent adverse event. The identification of DI-AKI is challenged by competing etiologies, clinical heterogeneity among patients, and a lack of accurate diagnostic tools. Our research aims to describe the clinical characteristics and predictive variables of DI-AKI.

Methods

We analyzed data from the Drug-Induced Renal Injury Consortium (DIRECT) study (NCT02159209), an international, multicenter, observational cohort study of enriched clinically adjudicated DI-AKI cases. Cases met the primary inclusion criteria if the patient was exposed to at least 1 nephrotoxic drug for a minimum of 24 hours prior to AKI onset. Cases were clinically adjudicated, and inter-rater reliability (IRR) was measured using Krippendorff's alpha. Variables associated with DI-AKI were identified using L1 regularized multivariable logistic regression. Model performance was assessed using the area under the receiver operating characteristic curve (ROC AUC).

Results

A total of 314 AKI cases met the eligibility criteria for this analysis, and 271 (86%) cases were adjudicated as DI-AKI. The majority of the AKI cases were recruited from the United States (68%). The most frequent causal nephrotoxic drugs were vancomycin (48.7%), nonsteroidal antiinflammatory drugs (18.2%), and piperacillin/tazobactam (17.8%). The IRR for DI-AKI adjudication was 0.309. The multivariable model identified age, vascular capacity, hyperglycemia, infections, pyuria, serum creatinine (SCr) trends, and contrast media as significant predictors of DI-AKI with good performance (ROC AUC 0.86).

Conclusion

The identification of DI-AKI is challenging even with comprehensive adjudication by experienced nephrologists. Our analysis identified key clinical characteristics and outcomes of DI-AKI compared to other AKI etiologies.

Safety and Feasibility Assessment of a Pharmacy-Driven AUC/MIC Vancomycin Dosing Protocol in a Multicenter Hospital System

Vancomycin is used for Gram-positive infections, including methicillin-resistant Staphylococcus aureus. The 2020 vancomycin guidelines described by M. J. Rybak, J. Le, T. P. Lodise, D. P. Levine, et al. (Am J Health Syst Pharm 77:835-864, 2020, https://doi.org/10.1093/ajhp/zxaa036) provided an update on vancomycin dosing, which recommended an optimal area under the concentration-time curve over 24 h to MIC (AUC/MIC) target of 400 to 600. In 2021, a pharmacy-driven AUC/MIC vancomycin dosing protocol was implemented across 12 Sentara Health System hospitals. The primary objective of this study was to assess if the pharmacy-driven AUC/MIC vancomycin dosing protocol led to fewer acute kidney injury (AKI) events than trough-based dosing. Secondary objectives included vancomycin duration, hospital length of stay, administered vancomycin dose during admission, vancomycin labs drawn during standard lab times, and cost. AKI was assessed in two separate ways: (i) modified AKIN (Acute Kidney Injury Network) criteria and (ii) a modified version from the vancomycin guidelines. Inferential statistics were used to analyze the results of this retrospective study. Per the AKIN definition, the rates of AKI were 13.9% (349/2,507) in the trough-based group and 14.9% (369/2,471) in the AUC/MIC-based group (P = 0.309). Per the definition of the vancomycin guidelines, the rates of AKI were 6.7% (169/2,507) in the trough-based group and 7.6% (187/2,471) in the AUC/MIC-based group (P = 0.258). A total of 52% (2,679/5,151) of vancomycin labs were obtained during standard lab times in the AUC group and 24% (1,144/4,766) in the trough group (P < 0.05). There was no difference in AKI events between AUC and trough dosing. Use of contrast dye may confound these results. AUC/MIC dosing was associated with more lab draws during standard times, a larger number of labs drawn per person, and less total use of vancomycin. IMPORTANCE In this article, we report that there were no differences in rates of acute kidney injury between trough-based vancomycin dosing and AUC/MIC-based vancomycin dosing across 12 hospitals. AUC/MIC dosing resulted in more vancomycin lab draws during standard lab draw times compared to trough dosing, thus making it more convenient for health care personnel. This study includes all uses for vancomycin, including empirical use, and all patient severity levels. Therefore, this research reflects real-world use of vancomycin in hospitals. AUC/MIC dosing is supported by various infectious disease societies. However, the feasibility of incorporating AUC/MIC dosing in hospitals is undetermined. This study is unique in that it includes hospitals of various sizes (small community hospitals and an academic teaching hospital), and it includes a feasibility component. Therefore, this study has broad applicability to other hospitals across the United States. This original research includes the clinical application of vancomycin in a multicenter health system.

Renal medicine in the intensive care unit: a narrative review

Kidney disease, both acute and chronic, is commonly encountered on the intensive care unit. Due to the role the kidneys play in whole body homeostasis, it follows that their dysfunction has wide-ranging implications and can affect prescribing and therapeutic management. This narrative review discusses the pathophysiology of acute kidney injury and chronic kidney disease, and how this relates to critically unwell patients. We cover several aspects of the management of renal dysfunction on the critical care unit, exploring some of the recurrent themes within the literature, including type and timing of kidney replacement therapy, management of acute kidney injury, as well as discussing how novel biomarkers for acute kidney injury may help to identify patients suffering from acute kidney injury as well as risk stratifying these patients. We discuss how early involvement of specialist nephrology services can improve outcomes in patients with kidney disease as well as offer valuable diagnostic and specialist management advice, particularly for patients with established end stage kidney disease and patients who are already known to nephrology services. We also explore some of the ongoing research questions that need to be answered within this arena.

Management of Patients With Kidney Disease in Need of Cardiovascular Catheterization: A Scientific Workshop Cosponsored by the National Kidney Foundation and the Society for Cardiovascular Angiography and Interventions

Patients with chronic kidney disease (CKD) are at an increased risk of developing cardiovascular disease (CVD), whereas those with established CVD are at risk of incident or progressive CKD. Compared with individuals with normal or near normal kidney function, there are fewer data to guide the management of patients with CVD and CKD. As a joint effort between the National Kidney Foundation and the Society for Cardiovascular Angiography and Interventions, a workshop and subsequent review of the published literature was held. The present document summarizes the best practice recommendations of the working group and highlights areas for further investigation.

N-acetylcysteine in the Prevention of Contrast-induced Acute Kidney Injury: a Systematic Review and Meta-analysis of Randomized Controlled Clinical Trials

Aim. To analyze the currently available published randomized controlled clinical trials to evaluate the effect of N-acetylcysteine on the incidence of contrast-induced acute kidney injury (CI-AKI).

Material and methods. The meta-analysis was performed in accordance with the PRISMA guidelines based on a search of existing literature in the PubMed/MEDLINE database for the period from 2015 to 16 February 2022. Keywords included MeSH terms «acute kidney injury» or «contrast-induced nephropathy» or «AKI» or «CIN» and «contrast media» and «N-acetylcysteine». The RoB 2 tool was used to assess study bias.

Results: When searching based on the initially selected statistics, 98 publications were identified, some of them were excluded from the analysis due to non-compliance with the inclusion criteria in this meta-analysis, 7 studies of unused sources of detection were ultimately selected, the total number of patients in the discovery was 10394.The results of the meta-analysis revealed that in patients treated with N-acetylcysteine CI-AKI developed with the same frequency as in patients who did not observe such therapy as a prophylaxis for this disease (odds ratio 1.06, 95% confidence interval 0.911.23, p=0.46).

Conclusion. The use of N-acytelcysteine does not offer any advantage in reducing the incidence of CI-AKI compared with the administration of saline solutions (sodium bicarbonate or sodium chloride 0.9%) or placebo.

Evaluation of Crocin Effect on Contrast-Induced Nephropathy Following Coronary Angiography or Angioplasty: A Randomized Controlled Trial

Contrast-induced nephropathy (CIN) is the third cause of hospital-acquired acute kidney injury. The CIN prophylactic strategies adopted to date, although not highly efficient, are mostly based on antioxidant activity and hydration therapy. This study was designed and conducted to evaluate crocin’s efficacy in the prevention of CIN in chronic kidney disease (CKD) patients undergoing coronary angiography/angioplasty. In this randomized clinical trial, a total of 110 eligible CKD stage 3 patients requiring contrast agent administration for coronary angiography/angioplasty were enrolled and randomly assigned to either crocin (n = 57) or control (n = 53) group. The patients in both groups received standard hydration therapy; nevertheless, in the crocin group, the patients were also orally administered three consecutive oral doses of 30 mg crocin tablets 1 day before up to 1 day after contrast media (CM) exposure. The primary endpoint was CIN incidence defined as an increase in serum creatinine (SrCr) level by ≥ 0.3 mg/dL or any change in urinary neutrophil gelatinase-associated lipocalin (NGAL) from the baseline within 48 hours of CM exposure. During 4 months, 130 patients were recruited. The mean age of the patients was 65.62 ± 9.05 years, and the majority of them were male (64.54%). The SrCr in the crocin group did not significantly increase within 48 hours of angiography/angioplasty. The changes in the urinary NGAL level were not significant in both groups. The CIN incidence was significantly lower in the crocin group than in the control group (1.75% and 13.2%; P = 0.028). Crocin administration plays an important nephron-protective role in the prevention of CIN.

The Development of Acute Kidney Injury in Burn Patients Undergoing Computed Tomography With Intravenous Contrast

Acute kidney injury (AKI) is a major complication of significant burn injuries and a significant cause of patient morbidity and mortality. Patients that sustain traumatic burn injuries may require computed tomography (CT) imaging as part of their initial trauma management. This multicenter retrospective chart review of patients admitted to two level I trauma centers with ≥10% TBSA burns between 2014 and 2017 aims to determine if patients with greater than 10% TBSA burns that received CT imaging with intravenous contrast were more likely to develop acute kidney injury during their admission. A total of 439 patients were included in the study. The average age was 45.3 years and average TBSA was 23.2%. Sixty-seven of the 439 patients underwent CT scans with IV contrast on admission. The rate of AKI between patients who did or did not receive CT scans was not statistically significant (9.1 vs 6.0%, P = 0.40). Patients who developed an AKI had higher TBSA (45.6 vs 21.1%, P < .01), amount of fluids per TBSA given within the first 24 hours (457.4 vs 321.6, P < .01), and mortality (71.1 vs 6.2%, P < .01) than those who did not develop an AKI. There was no significant difference in the development of acute kidney injury in burn patients who received CT scans with IV contrast on admission. Although there is a risk of contrast induced nephropathy, the risk is not increased in burn patients and this should not prevent a thorough evaluation to rule out additional life-threatening injuries in the burn trauma patient.

CONTRAST INDUCED ACUTE KIDNEY INJURY IS NOT A SITUATION TO BE AFRAID OF

Acute kidney injury (AKI), formerly called acute renal failure (ARF), is clinically manifested as a reversible acute increase in nitrogen waste products, as measured by blood urea nitrogen (BUN) and serum creatinine levels. Contrast induced acute kidney injury (CIAKI) is a potentially fatal complication of angiographic procedures caused by the use of contrast media (CM). It is the third most prevalent cause of hospital acquired acute renal damage, accounting for around up to 30% of cases. Contrast induced nephropathy (CIN) is defined as a greater than 25% or 0.5 mg/dl (44 μmol/l) increase in serum creatinine (Scr) from baseline within 3 days. More sensitive indicators of renal damage are sought, hence numerous tubular injury biomarkers are being studied. Multiple risk factors may lead to the development of CIN; these risk factors are classified as patient-related and procedure-related. Treatment of CIN Is primarily symptomatic and consist firstly of careful fluid and electrolyte management, although dialysis may be necessary in some cases. With available treatment options, prevention is the cornerstone of management.

Atrial Fibrillation and Chronic Kidney Disease-A Risky Combination for Post-Contrast Acute Kidney Injury

Atrial fibrillation (AF) symptoms may mimic coronary artery disease (CAD) which reflects the difficulties in qualifying AF patients for invasive diagnostics. A substantial number of coronary angiographies may be unnecessary or even put patients at risk of post-contrast acute kidney injury (PC-AKI), especially patients with chronic kidney disease (CKD). We aimed to investigate the hypothesis indicating higher prevalence of PC-AKI in patients with AF scheduled for coronary angiography. The study population comprised of 8026 patients referred for elective coronarography including 1621 with AF. In the comparison of prevalence of PC-AKI in distinguished groups we can see that kidney impairment was twice more frequent in patients with AF in both groups with CKD (CKD (+)/AF (+) 6.24% vs. CKD (+)/AF (−) 3.04%) and without CKD (CKD (−)/AF (+) 2.32% vs. CKD (−)/AF (−) 1.22%). In our study, post-contrast acute kidney disease is twice more frequent in patients with AF, especially in subgroup with chronic kidney disease scheduled for coronary angiography. Additionally, having in mind results of previous studies stating that AF is associated with non-obstructive coronary lesions on angiography, patients with AF and CKD may be unnecessarily exposed to contrast agent and possible complications.

Acute Kidney Injury Caused by Obstructive Nephropathy

Acute kidney injury secondary to obstructive nephropathy is a frequent event that accounts for 5 to 10% of all acute kidney injury cases and has a great impact on the morbidity and mortality in those affected. The obstruction in the urinary tract has a profound impact on kidney function due to damage produced by ischemic and inflammatory factors that have been associated with intense fibrosis. This pathology is characterized by its effects on the management of fluids, electrolytes, and the acid-base mechanisms by the renal tubule; consequently, metabolic acidosis, hyperkalemia, uremia, and anuria are seen during acute kidney injury due to obstructive nephropathy, and after drainage, polyuria may occur. Acute urine retention is the typical presentation. The diagnosis consists of a complete medical history and should include changes in urinary voiding and urgency and enuresis, history of urinary tract infections, hematuria, renal lithiasis, prior urinary interventions, and constipation. Imaging studies included tomography or ultrasound in which hydronephrosis can be seen. Management includes, in addition to drainage of the obstructed urinary tract system, providing supportive treatment, correcting all the metabolic abnormalities, and initiating renal replacement therapy when required. Although its recovery is in most cases favorable, it seems to be an undervalued event in nephrology and urology. This is because it is mistakenly believed that the resolution and recovery of kidney function is complete once the urinary tract is unobstructed. It can have serious kidney sequelae. In this review, we report the epidemiology, incidence, pathophysiological mechanisms, diagnosis, and treatment of acute kidney injury due to obstructive nephropathy.

The conundrum of contrast-induced acute kidney injury

More than sixty years have elapsed since contrast induced nephropathy (CIN) was first described in the medical literature. This term has since been extensively explored, with a variety of studies conducted to investigate its incidence and various mechanisms examined to explain its pathophysiology. However, the topic of CIN remains one of controversy with a widely variable and often questionable incidence derived from various studies. The past two decades have seen a surge in reports questioning the existing of CIN altogether and if more harm is actually being caused to patients out of fear of this potential complication. We have attempted to review relevant studies regarding CIN and highlight the key points of its surmised understanding. The review has a higher focus on more recent literature and updates, in order to determine if an accurate estimate can be made on the incidence of CIN. While there was certainly no lack of material available, practically all the studies reviewed were limited by one or more significant drawbacks that limited the reliability of their conclusions regarding CIN. Based on the information reviewed, the strengths and the flaws encountered in other studies can be used to design a randomized control trial that may help in concluding the longstanding debate on this topic. However due to time, financial, and perhaps even ethical constraints such a trial will be difficult to arrange, and so a definitive answer on CI-AKI, and whether it really exist, may continue to elude clinicians.