A meta-analysis of N-acetylcysteine in contrast-induced nephrotoxicity: unsupervised clustering to resolve heterogeneity

Association of N-acetylcysteine use with contrast-induced nephropathy: an umbrella review of meta-analyses of randomized clinical trials

Background

The effectiveness of N-acetylcysteine (NAC) in treating contrast-induced nephropathy (CIN) has been the subject of conflicting meta-analyses, but the strength of the evidence for these correlations between NAC use and CIN has not been measured overall.

Objective

To evaluate the data from randomized clinical studies (RCTs) that examined the relationships between NAC use and CIN in meta-analyses.

Methods

Between the creation of the database and April 2023, searches were made in PubMed, Cochrane Library, EMBASE, and Web of Science. N-acetylcysteine, contrast-induced nephropathy, or contrast-induced renal disease were among the search keywords used, along with terms including systematic review and meta-analysis. The Assessment of Multiple Systematic Reviews, version 2, which assigned grades of extremely low, low, moderate, or high quality to each meta-analysis's scientific quality, was used to evaluate each meta-analysis. The confidence of the evidence in meta-analyses of RCTs was evaluated using the Grading of Recommendation, Assessment, Development and Evaluations method, with evidence being rated as very low, low, moderate, or high.

Results

In total, 493 records were screened; of those, 46 full-text articles were assessed for eligibility, and 12 articles were selected for evidence synthesis as a result of the screening process. Based on the pooled data, which was graded as moderate-quality evidence, it can be concluded that NAC can decrease CIN (OR 0.72, 95% CI 0.65-0.79, p < 0.00001) and blood levels of serum creatinine (MD -0.09, 95% CI -0.17 to -0.01, p = 0.03). In spite of this, there were no associations between NAC and dialysis requirement or mortality in these studies.

Conclusion

The results of this umbrella review supported that the renal results were enhanced by NAC. The association was supported by moderate-quality evidence.

Systematic review registration

[https://clinicaltrials.gov/], identifier [CRD42022367811].

Radiographic Contrast Media and the Kidney

AKI is a potential complication of intravascular iodinated contrast exposure. Contrast-associated AKI, which typically manifests as small and transient decrements in kidney function that develop within several days of contrast administration, is associated with serious adverse outcomes, including progressive kidney dysfunction and death. However, a causal link between the small increases in serum creatinine that characteristically occur with contrast-associated AKI and serious adverse outcomes remains unproven. This is important given mounting evidence that clinically indicated, potentially lifesaving radiographic procedures are underutilized in patients with CKD. This has been hypothesized to be related to provider concern about precipitating contrast-associated AKI. Intravascular gadolinium-based contrast, an alternative to iodinated contrast that is administered with magnetic resonance imaging, has also been linked with potential serious adverse events, notably the development of nephrogenic systemic fibrosis in patients with severe impairment in kidney function. Patients hospitalized in the intensive care unit frequently have clinical indications for diagnostic and therapeutic procedures that involve the intravascular administration of contrast media. Accordingly, critical care providers and others treating critically ill patients should possess a sound understanding of the risk factors for and incidence of such outcomes, the ability to perform evidence-based risk-benefit assessments regarding intravascular contrast administration, and knowledge of empirical data on the prevention of these iatrogenic complications.

2021 ACC/AHA/SCAI Guideline for Coronary Artery Revascularization: A Report of the American College of Cardiology/American Heart Association Joint Committee on Clinical Practice Guidelines

AIM

The guideline for coronary artery revascularization replaces the 2011 coronary artery bypass graft surgery and the 2011 and 2015 percutaneous coronary intervention guidelines, providing a patient-centric approach to guide clinicians in the treatment of patients with significant coronary artery disease undergoing coronary revascularization as well as the supporting documentation to encourage their use.

METHODS

A comprehensive literature search was conducted from May 2019 to September 2019, encompassing studies, reviews, and other evidence conducted on human subjects that were published in English from PubMed, EMBASE, the Cochrane Collaboration, CINHL Complete, and other relevant databases. Additional relevant studies, published through May 2021, were also considered. Structure: Coronary artery disease remains a leading cause of morbidity and mortality globally. Coronary revascularization is an important therapeutic option when managing patients with coronary artery disease. The 2021 coronary artery revascularization guideline provides recommendations based on contemporary evidence for the treatment of these patients. The recommendations present an evidence-based approach to managing patients with coronary artery disease who are being considered for coronary revascularization, with the intent to improve quality of care and align with patients' interests.

2021 ACC/AHA/SCAI Guideline for Coronary Artery Revascularization: A Report of the American College of Cardiology/American Heart Association Joint Committee on Clinical Practice Guidelines

AIM

The guideline for coronary artery revascularization replaces the 2011 coronary artery bypass graft surgery and the 2011 and 2015 percutaneous coronary intervention guidelines, providing a patient-centric approach to guide clinicians in the treatment of patients with significant coronary artery disease undergoing coronary revascularization as well as the supporting documentation to encourage their use.

METHODS

A comprehensive literature search was conducted from May 2019 to September 2019, encompassing studies, reviews, and other evidence conducted on human subjects that were published in English from PubMed, EMBASE, the Cochrane Collaboration, CINHL Complete, and other relevant databases. Additional relevant studies, published through May 2021, were also considered.

STRUCTURE

Coronary artery disease remains a leading cause of morbidity and mortality globally. Coronary revascularization is an important therapeutic option when managing patients with coronary artery disease. The 2021 coronary artery revascularization guideline provides recommendations based on contemporary evidence for the treatment of these patients. The recommendations present an evidence-based approach to managing patients with coronary artery disease who are being considered for coronary revascularization, with the intent to improve quality of care and align with patients' interests.

Folic Acid Attenuates Contrast-Induced Nephropathy in Patients With Hyperhomocysteinemia Undergoing Coronary Catheterization: A Randomized Controlled Trial

Background: Hyperhomocysteinemia is a risk factor for contrast-induced nephropathy. Folic acid can attenuate such nephropathies in rats. The protective effect of folic acid against contrast-induced nephropathy has not been studied in humans. We aimed to investigate the effect of folic acid on the incidence of contrast-induced nephropathy (CIN) after coronary catheterization in patients with hyperhomocysteinemia.

Methods: This was a single-center, prospective, double-blind, randomized controlled trial (ClinicalTrials.gov, NCT02444013). In total, 412 patients (mean age: 65 ± 12 years, 268 male) with plasma homocysteine ≥15 μM, who underwent coronary arteriography (CAG) or percutaneous coronary intervention (PCI) from May 2015 to August 2018, were enrolled. Patients were randomly assigned to two groups: a treatment group (n = 203), taking 5 mg of folic acid (orally, three times/day) immediately after enrollment and for 72 h after operation, and a control group (n = 209), taking placebo. Contrast-induced nephropathy was defined as an increase in serum creatinine of >25% or 44 μM within 48 or 72 h after contrast medium administration.

Results: In total, 50 (12%) patients developed CIN after 48 h after catheterization, including 16 (8%) in the treatment group and 34 (16%) in the control group (P = 0.009). Meanwhile, 53 (13%) patients developed CIN after 72 h of CAG/PCI, including 18 (9%) in the treatment group and 35 (17%) in the control group (P = 0.017). The incidence of contrast-induced nephropathy in the treatment group was lower than that in the control group (P = 0.017). Logistic regression analysis confirmed that administration of folic acid was a protective factor against contrast-induced nephropathy (RD = 0.0788, 95%CI: 0.0105–0.1469, P = 0.019). We found no serious adverse events associated with folic acid. No death or hemodialysis occurred in either group.

Conclusions: Perioperative administration of folic acid attenuates the incidence of contrast-induced nephropathy after coronary catheterization in patients with hyperhomocysteinemia.

Clinical Trial Registration:ClinicalTrials.gov, identifier [NCT02444013].

Neuroimaging Considerations in Patients with Chronic Kidney Disease

Chronic Kidney Disease is a common medical condition that frequently overlaps with neurologic disease. Neuroimaging can be a useful tool to aid in the diagnoses of neurologic illness, including those that result from renal impairment. Some neuroimaging studies also have the potential to lead to adverse effects on the kidneys necessitating a thoughtful approach to selection of imaging modalities. In particular, multimodal imaging is becoming increasingly common in patients presenting with symptoms of acute stroke, a population that may be at higher risk for renal complications. This article will summarize the neuroimaging manifestations of conditions with shared renal and neurologic involvement and highlight considerations regarding the use of contrast media, nephrogenic systemic fibrosis, and metformin-associated lactic acidosis.

Preventing a nonexistent entity: the curious case of contrast and acute kidney injury

PURPOSE OF REVIEW

In recent years, doubt has been cast on the existence of contrast-induced acute kidney injury. The skepticism has stemmed from observational studies from large administrative healthcare databases. Although they correctly call that contrast-induced acute kidney injury is less common than previously thought, they cannot completely exclude selection bias.

RECENT FINDINGS

Though less common than previously thought, contrast-induced acute kidney injury still exists. The only prophylactic method that remains valid is that of isotonic volume expansion, which is still deemed beneficial in high-risk patients. N-acetylcysteine and sodium bicarbonate are ineffective and their use should be abandoned.

SUMMARY

Contrast-induced kidney injury should be defined based on clinical grounds, not merely on biochemical numbers. More research to validate a clinical definition is necessary in order to accurately re-examine its incidence.

Chow B, Shabana W, Hiremath S. A Systematic Review of the Effect of N-Acetylcysteine on Serum Creatinine and Cystatin C Measurements

INTRODUCTION

N-acetylcysteine (NAC) is an antioxidant that can regenerate glutathione and is primarily used for acetaminophen overdose. NAC has been tested and used for preventing iatrogenic acute kidney injury or slowing the progression of chronic kidney disease, with mixed results. There are conflicting reports that NAC may artificially lower measured serum creatinine without improving kidney function, potentially by assay interference. Given these mixed results, we conducted a systematic review of the literature to determine whether there is an effect of NAC on kidney function as measured with serum creatinine and cystatin C.

METHODS

A literature search was conducted to identify all study types reporting a change in serum creatinine after NAC administration. The primary outcome was change in serum creatinine after NAC administration. The secondary outcome was a change in cystatin C after NAC administration. Subgroup analyses were conducted to assess effect of creatinine assay (Jaffe vs. non-Jaffe and intravenous vs. oral).

RESULTS

Six studies with a total of 199 participants were eligible for the systematic review and meta-analysis. There was a small but significant decrease in serum creatinine after NAC administration overall (weighted mean difference [WMD], -2.80 μmol/L [95% confidence interval {CI} -5.6 to 0.0]; P = 0.05). This was greater with non-Jaffe methods (WMD, -3.24 μmol/L [95% CI -6.29 to -0.28]; P = 0.04) than Jaffe (WMD, -0.51 μmol/L [95% CI -7.56 to 6.53]; P = 0.89) and in particular with intravenous (WMD, -31.10 μmol/L [95% CI -58.37 to -3.83]; P = 0.03) compared with oral NAC (WMD, -2.5 μmol/L [95% CI -5.32 to 0.32]; P = 0.08). There was no change in cystatin C after NAC administration.

DISCUSSION

NAC causes a decrease in serum creatinine but not in cystatin C, suggesting analytic interference rather than an effect on kidney function. Supporting this, the effect was greater with non-Jaffe methods of creatinine estimation. Future studies of NAC should use the Jaffe method of creatinine estimation when kidney outcomes are being reported. Even in clinical settings, the use of an enzymatic assay when high doses of intravenous NAC are being used may result in underdiagnosis or delayed diagnosis of acute kidney injury.

PrevenTion of contrast-inducEd nephropAThy with urinE alkalinization: the TEATE study design

: Intravascular administration of iodinated contrast media is an essential tool for the imaging of blood vessels and cardiac chambers, as well as for percutaneous coronary and structural interventions. Along with the spreading of diagnostic and interventional procedures, the increasing incidence of contrast-induced nephropathy (CIN) has become an important and prognostically relevant problem. CIN is thought to be largely dependent on oxidative damage, and is a considerable cause of renal failure, being associated with prolonged hospitalization and significant morbidity/mortality. The most effective treatment strategy of this serious complication remains prevention, and several preventive measures have been extensively investigated in the last few years.Preprocedural hydration is the best-known and mostly accepted strategy. The administration of sodium bicarbonate has controversial effects, and is likely to be ineffective when the infused dose is unable to achieve adequate urine alkalinization. Since alkaline pH suppresses the production of free radicals, increasing urine pH would be an attractive goal for CIN prevention.In a prospective randomized controlled, open-label clinical trial we will test the hypothesis that urine alkalinization with either oral or intravenous bicarbonate on top of hydration alone is the main determinant of CIN prevention (primary endpoint) in a population of patients with moderate or severe chronic kidney disease scheduled for coronary angiography and/or angioplasty. If we then demonstrate nonsignificant differences in urine alkalinization and incidence of CIN between the two bicarbonate groups (secondary endpoint), a practical implication will be that oral administration is preferable for practical reasons over the administration of intravenous bicarbonate.

Burden, risk factors and outcomes of hyperemesis gravidarum in low-income and middle-income countries (LMICs): systematic review and meta-analysis protocol

INTRODUCTION

Hyperemesis gravidarum (HG) is a pregnancy condition characterised by excessive nausea and vomiting resulting in dehydration, weight loss and serious adverse pregnancy outcomes including termination of pregnancies. Even though evidence in low-income and middle-income countries (LMICs) is limited, the prevalence of HG in pregnancy ranges from 0.3% to 10.8%. With this systematic review and meta-analysis, we aim to determine the prevalence/burden, risk factors, and maternal and perinatal outcomes of HG in LMICs.

METHODS

PubMed, CINAHL, EMBASE, EBSCO, Ovid maternity and infant care databases, Cochrane Database of Systematic Reviews, Web of Science and SCOPUS databases will be searched. Reference lists of selected articles will be assessed in order to identify other potential studies of interest. Observational studies and (non) randomised controlled trials conducted from January 2000 to September 2018 in LMIC will be included. A weighted inverse-variance meta-analysis using fixed-effects and random-effects model will be done to generate a pooled estimate. Funnel plot and Egger's regression statistical test will be applied to check publication bias. Heterogeneity among studies will be checked using Τ² to determine dispersion. Moreover, meta-regression analysis will be performed to investigate the source of heterogeneity. STATA V.14 will be used to analyse the data.

ETHICS AND DISSEMINATION

Formal ethical approval and patient consent are not required; as primary data collection will not be employed. The result will be published in a peer-reviewed scientific journal and will be presented at scientific conferences and public press.

PROSPERO REGISTRATION NUMBER

CRD42018096284.

Pharmacological interventions for the prevention of contrast-induced acute kidney injury in high-risk adult patients undergoing coronary angiography: a systematic review and meta-analysis of randomised controlled trials

Objective

Quantify the efficacy of strategies to prevent contrast-induced acute kidney injury (CI-AKI) in high-risk patients undergoing coronary angiography (CAG) with or without percutaneous coronary intervention (PCI).

Background

CI-AKI remains a common problem. The renoprotective efficacy of existing pharmacological agents remains uncertain in high-risk populations.

Methods

Systematic review and meta-analysis of randomised controlled trials (RCTs) to compare different strategies versus hydration in patients with chronic kidney disease (CKD) undergoing CAG±PCI. Primary outcome was incident CI-AKI. Fixed-effects meta-analyses estimated ORs, 95% CIs and heterogeneity.

Results

Forty-eight RCTs were included. Seven pharmacological strategies were evaluated by multiple RCTs and 10 by one RCT each. These had varying risk of bias; >25% of trials were at high risk of performance bias. Five strategies significantly reduced the odds of CI-AKI: N-acetylcysteine (NAC) (27 trials, 5694 participants; OR=0.77, 95% CI 0.65 to 0.91, p=0.002, I²=36%), ascorbic acid (four trials, 759 participants; OR=0.59, 95% CI 0.39 to 0.89, p=0.01, I²=0%), statin (two trials, 3234 participants; OR=0.59, 95% CI 0.39 to 0.89, p=0.75, I²=0%), trimetazidine (two trials, 214 participants; OR=0.27, 95% CI 0.10 to 0.71, p=0.01, I²=0%) and nicorandil (two trials, 389 participants; OR=0.47, 95% CI 0.23 to 0.94, p=0.03, I²=52%). Theophylline had a similar, but non-significant, effect. A subgroup analysis found that the benefit of NAC was highest in patients requiring a high-contrast dose.

Conclusions

Several drugs are renoprotective in patients with CKD undergoing CAG±PCI. The evidence is strongest for NAC. We recommend that NAC should be used when a high dose of contrast is anticipated.

Trial registration number

PROSPERO registration CRD42014014704.

Open Science Framework link: https://osf.io/vxg7d/?view_only=62bad0404b18405abd39ff2ead2575a8

Adherence to prenatal iron-folic acid supplementation in low- and middle-income countries (LMIC): a protocol for systematic review and meta-analysis

BACKGROUND

Daily iron-folic acid supplementation reduces anemia and various adverse obstetric outcomes such as preterm delivery, low birthweight, hemorrhage, and perinatal and maternal morbidity and mortality. However, its supplementation has not been successful that attributed to several determinants including poor adherence. Therefore, we aimed to conduct a systematic review and meta-analysis on the prevalence and determinants of adherence to prenatal iron-folic acid supplementation in low- and middle-income countries. In addition, we will develop a conceptual framework in the context of low- and middle-income countries (LMIC).

METHODS/DESIGN

We will search PubMed, MEDLINE, EMBASE, EBSCO, Web of Science, SCOPUS, WHO Global Index Medicus, and African Journals Online (AJOL) databases to retrieve relevant literatures. Observational (i.e., case-control, cohort, cross-sectional, survey, and surveillance reports) and quasi-randomized and randomized controlled trial studies conducted in LMIC will be included. The Newcastle-Ottawa Scale (NOS) and Joanna Briggs Institute (JBI) critical appraisal checklist will be used to assess the quality of observational and randomized controlled trial studies respectively. The pooled prevalence and odds ratio of determinants of adherence will be generated using a weighted inverse-variance meta-analysis model. Statistical heterogeneity among studies will be assessed by Cochran's Q χ2 statistics and Higgins (I2 statistics) method. The result will be presented using forest plots and Harvest plots when necessary. Furthermore, we will perform Jackknife sensitivity and subgroup analysis. Data will be analyzed using comprehensive meta-analysis software (version 2).

DISCUSSION

Contemporary evidence about the prevalence and determinants of adherence in LMIC will be synthesized to generate up-to-date knowledge. To our knowledge, this is the first systematic review. It would have substantial implications for researchers, clinicians, and policymakers for optimizing maternal and child health outcomes in LMIC.

SYSTEMATIC REVIEW REGISTRATION

The protocol has been registered on International Prospective Register of Systematic Review (PROSPERO), University of York Center for Reviews and Dissemination ( https://www.crd.york.ac.uk/ ), registration number CRD42017080245 .

N-acetylcysteine transforms necrosis into apoptosis and affords tailored protection from cisplatin cytotoxicity

Nephrotoxicity is the main limitation to the dosage and anticancer efficacy of cisplatin. Cisplatin produces tubular epithelial cell apoptosis and necrosis depending on the concentration of the drug. Protection from cisplatin nephrotoxicity must therefore tackle both cell death modes. For its ability to reduce cisplatin reactivity, in addition to its antioxidant effect, we tested and found that N-acetylcysteine (NAC) was most effective at inhibiting cisplatin cytotoxicity. NAC has no significant effect on cell death induced by either cycloheximide or Fas activation, indicating a rather selective action. Pt-DNA-binding experiments suggest that the differential effectiveness of NAC is due to its capacity to quench cisplatin reactivity inside the cell. NAC abolishes cisplatin-induced apoptosis, and transforms the necrosis induced by high concentrations of cisplatin into apoptosis. In fact, NAC allows the anti-apoptotic molecule Bcl-2 to reduce the cell death caused by pro-necrotic concentrations of cisplatin, to a significantly greater extent than in the absence of NAC. In rats, a dosage of NAC that significantly ameliorates cisplatin nephrotoxicity, has little effect on gentamicin nephrotoxicity. These characteristics provide NAC with a rationale as a potential nephroprotectant specifically tailored to and especially effective for therapeutic courses with platinated antineoplastics, which prompts to deepening into further preclinical knowledge, and to initiate clinical studies with NAC and mixed therapies composed of NAC and antiapoptotic drugs.

Acute Kidney Injury (AKI)

Kidneys perform a multitude of essential functions within the human body. Of these the most important are (1) maintaining pH through regulation of acid/base levels and (2) excreting end products of metabolism. As for most organ-systems, these functions are especially important for healing following trauma and/or surgery and decline with age. Acute Kidney Injury (AKI) is one of the common forms of organ failures seen in the ICU and elderly patients are more prone to it. The causes maybe classified as Prerenal (inadequate perfusion), renal (inherent kidney disease) and post-renal (urinary obstruction). Preventing AKI should be an important concern in all critically ill patients but especially important in the elderly patients since the development of AKI can significantly increase in-hospital mortality. Once AKI has set in a systematic and step-wise approach of diagnosis and management is key to avoiding adverse outcomes.

Contrast-induced acute kidney injury: the importance of diagnostic criteria for establishing prevalence and prognosis in the intensive care unit

OBJECTIVE

To establish whether there is superiority between contrast-induced acute kidney injury and contrast-induced nephropathy criteria as predictors of unfavorable clinical outcomes.

METHODS

Retrospective study carried out in a tertiary hospital with 157 patients undergoing radiocontrast infusion for propaedeutic purposes.

RESULTS

One hundred forty patients fulfilled the inclusion criteria: patients who met the criteria for contrast-induced acute kidney injury (59) also met the criteria for contrast-induced nephropathy (76), 44.3% met the criteria for KDIGO staging, 6.4% of the patients required renal replacement therapy, and 10.7% died.

CONCLUSION

The diagnosis of contrast-induced nephropathy was the most sensitive criterion for renal replacement therapy and death, whereas KDIGO showed the highest specificity; there was no correlation between contrast volume and progression to contrast-induced acute kidney injury, contrast-induced nephropathy, support dialysis or death in the assessed population.

Prevention of acute kidney injury and protection of renal function in the intensive care unit: update 2017 : Expert opinion of the Working Group on Prevention, AKI section, European Society of Intensive Care Medicine

BACKGROUND

Acute kidney injury (AKI) in the intensive care unit is associated with significant mortality and morbidity.

OBJECTIVES

To determine and update previous recommendations for the prevention of AKI, specifically the role of fluids, diuretics, inotropes, vasopressors/vasodilators, hormonal and nutritional interventions, sedatives, statins, remote ischaemic preconditioning and care bundles.

METHOD

A systematic search of the literature was performed for studies published between 1966 and March 2017 using these potential protective strategies in adult patients at risk of AKI. The following clinical conditions were considered: major surgery, critical illness, sepsis, shock, exposure to potentially nephrotoxic drugs and radiocontrast. Clinical endpoints included incidence or grade of AKI, the need for renal replacement therapy and mortality. Studies were graded according to the international GRADE system.

RESULTS

We formulated 12 recommendations, 13 suggestions and seven best practice statements. The few strong recommendations with high-level evidence are mostly against the intervention in question (starches, low-dose dopamine, statins in cardiac surgery). Strong recommendations with lower-level evidence include controlled fluid resuscitation with crystalloids, avoiding fluid overload, titration of norepinephrine to a target MAP of 65-70 mmHg (unless chronic hypertension) and not using diuretics or levosimendan for kidney protection solely.

CONCLUSION

The results of recent randomised controlled trials have allowed the formulation of new recommendations and/or increase the strength of previous recommendations. On the other hand, in many domains the available evidence remains insufficient, resulting from the limited quality of the clinical trials and the poor reporting of kidney outcomes.

Update on the renal toxicity of iodinated contrast drugs used in clinical medicine

An important side effect of diagnostic contrast drugs is contrast-induced acute kidney injury (CI-AKI; a sudden decrease in renal function) occurring 48-72 hours after injection of a contrast drug that cannot be attributed to other causes. Its existence has recently been challenged, because of some retrospective studies in which the incidence of AKI was not different between subjects who received a contrast drug and those who did not, even using propensity score matching to prevent selection bias. For some authors, only patients with estimated glomerular filtration rate <30 mL/min/1.73 m2 are at significant risk of CI-AKI. Most agree that when renal function is normal, there is no CI-AKI risk. Many experimental studies, however, are in favor of the existence of CI-AKI. Contrast drugs have been shown to cause the following changes: renal vasoconstriction, resulting in a rise in intrarenal resistance (decrease in renal blood flow and glomerular filtration rate and medullary hypoxia); epithelial vacuolization and dilatation and necrosis of proximal tubules; potentiation of angiotensin II effects, reducing nitric oxide (NO) and causing direct constriction of descending vasa recta, leading to formation of reactive oxygen species in isolated descending vasa recta of rats microperfused with a solution of iodixanol; increasing active sodium reabsorption in the thick ascending limbs of Henle's loop (increasing O2 demand and consequently medullary hypoxia); direct cytotoxic effects on endothelial and tubular epithelial cells (decrease in release of NO in vasa recta); and reducing cell survival, due to decreased activation of Akt and ERK1/2, kinases involved in cell survival/proliferation. Prevention is mainly based on extracellular volume expansion, statins, and N-acetylcysteine; conflicting results have been obtained with nebivolol, furosemide, calcium-channel blockers, theophylline, and hemodialysis.

Risk of contrast induced nephropathy in diabetic patients affected by critical limb ischemia and diabetic foot ulcers treated by percutaneous transluminal angioplasty of lower limbs

BACKGROUND

The aim of this study is to evaluate the risk of contrast induced nephropathy (CIN) in diabetic patients with critical limb ischemia (CLI) and foot ulcers (FUs) treated by percutaneous transluminal angioplasty of lower limbs.

METHODS

The study group was composed of 145 diabetic patients who underwent a limb salvage protocol because of CLI and FUs between 2012 and 2015. All patients received a prophylactic strategy against the administration of contrast medium. Serum creatinine (SCr) levels were evaluated the day of procedure and for 3 days after. CIN was considered in case of increase of 25% of SCr in comparison to baseline value or an absolute increase of at least 0.5 mg/dl without other interfering factors.

RESULTS

CIN occurred in 9% (14/145) of the cases. In the 1-year follow-up SCr returned to baseline values in 10 patients (71 %), 3 patients died (21%), and 1 patient had a major cardiovascular event (7%). No patients required dialysis. The risk was independent of chronic kidney disease stage. The rate of contrast nephropathy in each stage (X = 0.27) was as follows: 3/20 (15%) in stage 2; 3/66 (4.6%) in stage 3, 7/51 (13.7%) in stage 4; and 1/8 (12.5%) in stage 5. At the univariate analysis factors predicting this risk were anemia (HR 95% 2.5 [CI 1.8-4.2] P = .039) and heart failure (HR 95% 2.6 [CI 2.1-4.6] P = .038), while any significant variable was found at multivariate analysis.

CONCLUSIONS

Peripheral percutaneous transluminal angioplasty in diabetic patients with CLI and FUs can be performed with a good safety factor and a low risk of contrast medium toxicity.

Design of Clinical Trials in Acute Kidney Injury: Lessons from the Past and Future Directions

Acute kidney injury (AKI) is a common condition with multiple etiologies and variable clinical findings and pathologic manifestations. AKI is associated with serious adverse clinical outcomes, including the development of de novo chronic kidney disease, accelerated progression of pre-existing chronic kidney disease, end-stage kidney disease, and increased mortality. Past research has advanced our understanding of the pathophysiology, epidemiology, and outcomes of AKI significantly, however, little progress has been made in the development of evidence-based interventions for its prevention and treatment. In this review, we discuss key considerations in the design of clinical trials in AKI and highlight significant methodologic limitations that precluded many past studies from determining the effectiveness of preventive and therapeutic strategies for this common and serious condition.

Efficacy of Short-Term Statin Treatment for the Prevention of Contrast-Induced Acute Kidney Injury in Patients Undergoing Coronary Angiography/Percutaneous Coronary Intervention: A Meta-Analysis of 21 Randomized Controlled Trials

BACKGROUND

The results of previous studies have been contradictory in terms of the efficacy of statin treatment in preventing contrast-induced acute kidney injury (CI-AKI) and clinical adverse events (AEs).

OBJECTIVE

This meta-analysis was undertaken to assess the role of short-term statin treatment in the prevention of CI-AKI and clinical AEs.

METHODS

We searched the Cochrane Library, EMBASE, and PubMed databases for randomized controlled trials (RCTs) with the development of CI-AKI as a primary outcome. Secondary outcomes were the post-procedural serum creatinine (SCr) level, estimated glomerular filtration rate (eGFR), and development of AEs. We also performed prespecified subgroup analyses.

RESULTS

A total of 21 RCTs involving 7746 patients were included. Short-term statin treatment significantly reduced the risk of CI-AKI [risk ratio (RR) 0.57; 95 % confident interval (CI) 0.47-0.69; p < 0.00001) and was associated with a lower post-procedural SCr level and a higher eGFR. High-dose statins resulted in a lower incidence of CI-AKI than the lower-dose statins. In addition, the benefit was seen across various subgroups for patients at risk of CI-AKI, statin-naïve patients, and East Asians, regardless of statin type, definition of CI-AKI, use of N-acetylcysteine (NAC) and hydration, and osmolality of contrast. However, there was no significant difference between the two groups in terms of the incidence of AEs.

CONCLUSIONS

The meta-analysis suggests that short-term statin treatment can effectively prevent CI-AKI, and the benefit is also observed in high-risk patients, statin-naïve patients, and an East Asian population. However, the effect of simvastatin for the prevention of CI-AKI, of statins for the prevention of AEs, and whether high-dose statins have a better effect than lower-dose statins are all still uncertain.

How Strong Is the Evidence for Sodium Bicarbonate to Prevent Contrast-Induced Acute Kidney Injury After Coronary Angiography and Percutaneous Coronary Intervention?

Hydration with sodium bicarbonate is one of the strategies to prevent contrast-induced acute kidney injury (CI-AKI). The purpose of this study was to determine how strong is the evidence for sodium bicarbonate to prevent CI-AKI after coronary angiography (CAG) and/or percutaneous coronary intervention (PCI).We conducted PubMed, EMBASE, and CENTRAL databases to search for randomized controlled trials (RCTs) comparing the efficacy of sodium bicarbonate with sodium chloride to prevent CI-AKI after CAG and/or PCI. Relative risk (RR), standardized mean difference (SMD), or weighted mean difference (WMD) with 95% confidence intervals (CIs) was calculated. Heterogeneity, publication bias, and study quality were evaluated, sensitivity analyses, cumulative analyses, and subgroup analyses were performed. The risk of random errors was assessed by trial sequential analysis (TSA).Sixteen RCTs (3537 patients) met the eligibility criteria. Hydration with sodium bicarbonate showed significant beneficial effects in preventing CI-AKI (RR 0.67; 95% CI: 0.47-0.96, P = 0.029), decreasing the change in serum creatinine (SCr) (SMD -0.31 95% CI: -0.55 to -0.07, P = 0.011) and estimated glomerular filtration rate (eGFR) (SMD -0.17 95% CI: -0.30 to -0.04, P = 0.013). But no significant differences were observed in the requirement for dialysis (RR 1.11; 95% CI: 0.60-2.07, P = 0.729), mortality (RR 0.71; 95% CI: 0.41-1.21, P = 0.204) and reducing the length of hospital stay (LHS) (WMD -1.47; 95% CI: -4.14 to 1.20, P = 0.279). The result of TSA on incidence of CI-AKI showed the required information size (RIS = 6614) was not reached and cumulative z curve did not cross TSA boundary. The result of TSA on the requirement for dialysis and mortality demonstrated the required information sizes (RIS = 170,510 and 19,516, respectively) were not reached, and the cumulative z-curve did not cross any boundaries.The evidence that sodium bicarbonate reduces the incidence of CI-AKI is encouraging but more well-designed randomized controlled trails are required to allow definitive firm conclusion to be drawn.

Evaluation of the protective effect of N-acetylcysteine on contrast media nephropathy

INTRODUCTION

Intravenous contrast agents can cause acute decline in kidney function, especially in patients with risk factors.

OBJECTIVES

In this study, we aimed to examine the ameliorative effect N-acetylcysteine (NAC) to reduce the incidence of contrast nephropathy.

PATIENTS AND METHODS

This study was a prospective, randomized, double-blind clinical trial on 150 patients who underwent coronary angiography. The study was carried out on patients undergoing coronary angiography. Patients were randomly assigned into 2 groups of intervention group and control subjects. Intervention group took NAC 600 mg orally twice a day. It was administered one day before angiography and continued until the second day after angiography. Control subjects received saline only. Serum creatinine was measured before and three days after coronary angiography.

RESULTS

There was no significant difference between intervention and control groups at baseline (P > 0.05). However, there was a significant decline in creatinine level among NAC patients (P = 0.001). Saline group had significantly higher proportion of nephropathy cases than NAC patients Conclusion: We found that the consumption of NAC is useful for contrast induced nephropathy (CIN) prevention.

Renal-related adverse effects of intravenous contrast media in computed tomography

Renal-related adverse effects of intravascular contrast media (CM) include contrast-induced nephropathy in computed tomography and angiography. While large retrospective studies have been published, the exact pathogenesis of this condition is still unknown. We review the main international guidelines, including the American College of Radiology white paper and the guidelines of European Society of Urogenital Radiology, Royal College of Radiologists and Canadian Association of Radiologists, as well as their references, regarding this subject. We present a simplified, concise approach to renal-related adverse effects of CM, taking into consideration the basis for each recommendation in these published guidelines. This will allow the reader to better understand the rationale behind appropriate patient preparation for cross-sectional imaging.

Contrast Medium-Induced Acute Kidney Injury

Contrast medium-induced acute kidney injury (CI-AKI) is a predominant cause of hospital-acquired renal insufficiency. With an increasing number of contrast medium-enhanced radiological procedures being performed in a rapidly increasing ageing population in the Western world, it is imperative that more attention is given to understand the aetiology of CI-AKI to devise novel diagnostic methods and to formulate effective prophylactic and therapeutic regimens to reduce its incidence and its associated morbidity and mortality. This article presents high-yield information on the above-mentioned aspects of CI-AKI, primarily based on results of randomised controlled trials, meta-analyses, systematic reviews and international consensus guidelines.

Comparison between theophylline, N-acetylcysteine, and theophylline plus N-acetylcysteine for the prevention of contrast-induced nephropathy

BACKGROUND

Few studies compared the efficacy of theophylline with N-acetylcysteine or evaluated the efficacy of combination therapy in the prevention of contrast-induced nephropathy (CIN). We compared the efficacy of theophylline, N-acetylcysteine, and the combination of these agents in the prevention of CIN.

METHODS

This randomized controlled trial was conducted on 96 patients referring consecutively to the Shahid Chamran University Hospital in Isfahan, Iran, for elective coronary angiography (with our without angioplasty). Patients with at least moderate risk for CIN were included and were randomized to receive theophylline (200 mg), N-acetylcysteine (600 mg), or theophylline + N-acetylcysteine, twice a day, from 24 h before to 48 h after administration of the contrast material. A non-ionic, low-osmolar contrast material was used. Serum creatinine was measured before and 48 h after contrast material injection.

RESULTS

Serum creatinine was increased by 6.83 ± 15.32% with theophylline, 13.09 ± 14.63% with N-acetylcysteine, and 5.45 ±1 3.96% with theophylline + N-acetylcysteine after contrast material injection (between group P = 0.072). Controlling for Mehran risk score, baseline serum creatinine, and contrast volume, the change in serum creatinine level was lower with theophylline compared with N-acetylcysteine (F = 4.79, P = 0.033), and with theophylline + N-acetylcysteine compared with N-acetylcysteine (F = 5.78, P = 0.020). CIN (increase in creatinine of ≥ 0.5 mg/dl or ≥ 25% from the baseline) was occurred in 20%, 21.9%, and 7.1% of patients in the theophylline, N-acetylcysteine, and theophylline + N-acetylcysteine groups, respectively (P = 0.260).

CONCLUSION

Theophylline is superior to N-acetylcysteine in preventing contrast-induced renal dysfunction, but the combination with N-acetylcysteine is not superior to theophylline alone in this regard. Further trials with larger sample of patients are warranted.

Pre-diabetes and the risk of contrast induced nephropathy in patients undergoing coronary angiography or percutaneous intervention

BACKGROUND

Contrast induced nephropathy (CIN) is a complication of coronary angiography/percutaneous intervention (PCI). It is known that diabetes is an independent risk factor for CIN, but we have no data regarding the association between CIN and glycemic levels in patients without diabetes. Aim of our study was to evaluate whether high level of glycated-haemoglobin in patients without diabetes is associated with an increased risk of CIN.

METHODS

A total of 1324 patients without diabetes, undergoing elective/urgent coronary angiography/angioplasty were divided according to quartiles of baseline glycated-haemoglobin. CIN was defined as an absolute ≥ 0.5mg/dL or a relative ≥ 25% increase in creatinine level at 24-48 h after the procedure.

RESULTS

Patients with elevated glycated-haemoglobin were older, with hypertension, metabolic syndromes, previous history of AMI, PCI and CABG. They had higher gycaemia, fasting-glycaemia and triglycerides but lower HDL-cholesterol. Patients with higher glycated-haemoglobin were more often on therapy with statins, diuretics and calcium-antagonist at admission, had higher basal, 24 and 48 h creatinine, lower creatinine clearance and lower ejection fraction. They had the highest incidence of PCI and contrast volume-eGFR rate. CIN occurred in 10.6% of patients with a linear association with glycated-haemoglobin (p=0.001). No relationship was found between glycaemia/fasting glycaemia at admission and CIN. The multivariate analysis confirmed the association between elevated glycated haemoglobin (above the median value 5.7%) and the risk of CIN after adjustment for baseline confounding factors (Adjusted OR [95% CI]=1.69 [1.14-2.51], p=0.009). In fact, the results were consistent in major high-risk subgroups.

CONCLUSION

This is the first study showing that among patients without diabetes undergoing coronary angiography/PCI elevated glycated-haemoglobin but not glucose levels is independently associated with the risk of CIN.

[Iodinated contrast agents used in Radiology]

Iodinated contrast media are widely used in Radiology practices with a very low rate of adverse effects, being contrast-induced nephropathy the most serious one. In the majority of cases it is temporary and reversible, even though it can increase the inhospital morbidity and mortality in patients with risk factors. We will describe the various measures of prevention, being hydration and use of non-ionic contrast low osmolality those which have demonstrated greater effectiveness. Precautions to be taken in some risk situations, as patients treated with metformin or with impaired renal function, are also discussed.

Risk factors for hemodialysis and mortality in patients with contrast-induced nephropathy

The purpose of this study was to identify risk factors for renal failure requiring hemodialysis and mortality in patients who developed contrast-induced nephropathy (CIN) after cardiac catheterization. Out of 13,742 patients who received cardiac catheterization at Westchester Medical Center/New York Medical College from 2005 to 2008, 268 patients (2%) with a discharge diagnosis of renal failure were screened for CIN. CIN was defined as either a >25% increase of the serum creatinine or an absolute increase in serum creatinine of 0.5 mg/dL within the first 48 hours of the procedure. Chart reviews were performed on 80 patients (1%) who met the criteria for CIN. The 80 patients in the study included 46 men and 34 women, mean age 69 ± 14 years. Of the 80 patients, 18 patients (23%) died, and 22 patients (28%) developed renal failure requiring hemodialysis. Stepwise logistic regression analysis showed that independent risk factors for mortality were the use of calcium channel blockers [odds ratio = 0.0025, 95% confidence interval (CI), 0.0001-0.1210, P < 0.01], catecholamine use (odds ratio = 71.2177, 95% CI, 4.2153-1203, P < 0.01), circulatory failure with lactic acidosis (odds ratio = 32.1405, 95% CI, 2.6331-392, P < 0.01), and renal failure requiring hemodialysis (odds ratio = 17.0376, 95% CI, 1.2344-235, P < 0.05). Significant independent risk factors for renal failure requiring hemodialysis were smoking (odds ratio = 0.06, 95% CI, 0.0045-0.8080, P < 0.05), N-acetylcysteine use (odds ratio = 0.08, 95% CI, 0.0148-0.4179, P < 0.01), anemia (odds ratio = 11.32, 95% CI, 2.57-50, P < 0.01), and circulatory failure with lactic acidosis (odds ratio = 9.76, 95% CI, 2.37-40, P < 0.01). Our data showed that risk factors for mortality in patients with CIN were catecholamine use, circulatory failure with lactic acidosis, and renal failure requiring hemodialysis. Risk factor for reducing mortality in patients with CIN was calcium channel blocker use. Significant risk factors for renal failure requiring hemodialysis were anemia, and circulatory failure with lactic acidosis. Risk factors for reducing renal failure requiring hemodialysis were N-acetylcysteine use and smoking.

Elevated Homocysteine and the Risk of Contrast-Induced Nephropathy

Contrast-induced nephropathy (CIN) is a common complication in patients with impaired kidney function undergoing coronary angiography/angioplasty. We evaluated whether elevated homocysteine (known to be associated with free radical generation and oxidative stress) increases the risk of CIN. Patients (n = 876) with creatinine clearance <60 mL/min undergoing coronary angiography or percutaneous coronary intervention (PCI) were divided into tertiles of homocysteine levels. Contrast-induced nephropathy was defined as ≥0.5 mg/dL or ≥25% creatinine increase 24 to 48 hours post-PCI. A significant relationship was observed between homocysteine levels and the risk of CIN ( P = .033), confirmed after correction for baseline confounding factors, adjusted odds ratio, OR (95% confidence interval, [CI]) = 1.68 (1.09-2.59), P = .019. This association was also significant applying the new definition of contrast-induced acute kidney injury (11.9% in group 1, 10.4% in group 2, and 22.8% in group 3; P < .001), adjusted OR (95% CI) = 1.96 (1.3-2.95), P = .001. Future studies are needed to confirm our findings and to define the role of homocysteine in CIN.

Prophylaxis of contrast-induced nephrotoxicity

Contrast-induced nephrotoxicity (CIN) is a form of acute kidney injury that follows intravascular contrast media exposure. CIN may be preventable because its risk factors are well established and the timing of renal insult is commonly known in advance. However, contrast-induced nephrotoxicity is still the third leading cause of iatrogenic renal failure. This important complication accounts up to 10% of acute renal failure cases in hospitalized patients and it is associated with increased short- and long-term morbidity and mortality. Prolonged hospitalization follows and overall increases healthcare resource utilization. This paper will discuss the various prophylactic procedures tested in clinical trials.

Pharmacological strategies to prevent contrast-induced acute kidney injury

Contrast-induced acute kidney injury (CI-AKI) is the most common iatrogenic cause of acute kidney injury after intravenous contrast media administration. In general, the incidence of CI-AKI is low in patients with normal renal function. However, the rate is remarkably elevated in patients with preexisting chronic kidney disease, diabetes mellitus, old age, high volume of contrast agent, congestive heart failure, hypotension, anemia, use of nephrotoxic drug, and volume depletion. Consequently, CI-AKI particularly in high risk patients contributes to extended hospitalizations and increases long-term morbidity and mortality. The pathogenesis of CI-AKI involves at least three mechanisms; contrast agents induce renal vasoconstriction, increase of oxygen free radicals through oxidative stress, and direct tubular toxicity. Several strategies to prevent CI-AKI have been evaluated in experimental studies and clinical trials. At present, intravascular volume expansion with either isotonic saline or sodium bicarbonate solutions has provided more consistent positive results and was recommended in the prevention of CI-AKI. However, the proportion of patients with risk still develops CI-AKI. This review critically evaluated the current evidence for pharmacological strategies to prevent CI-AKI in patients with a risk of developing CI-AKI.

Canadian Association of Radiologists consensus guidelines for the prevention of contrast-induced nephropathy: update 2012

PURPOSE

Contrast-induced acute kidney injury or contrast-induced nephropathy (CIN) is a significant complication of intravascular contrast medium (CM). These guidelines are intended as a practical approach to risk stratification and prevention. The major risk factor that predicts CIN is pre-existing chronic kidney disease.

METHODS

Members of the committee represent radiologists and nephrologists across Canada. The previous guidelines were reviewed, and an in-depth up-to-date literature review was carried out.

RESULTS

A serum creatinine level (SCr) should be obtained, and an estimated glomerular filtration rate (eGFR) should be calculated within 6 months in the outpatient who is stable and within 1 week for inpatients and patients who are not stable. Patients with an eGFR of ≥ 60 mL/min have an extremely low risk of CIN. The risk of CIN after intra-arterial CM administration appears be at least twice that after intravenous administration. Fluid volume loading remains the single most important measure, and hydration regimens that use sodium bicarbonate or normal saline solution should be considered for all patients with GFR < 60 mL/min who receive intra-arterial contrast and when GFR < 45 mL/min in patients who receive intravenous contrast. Patients are most at risk for CIN when eGFR < 30 mL/min. Additional preventative measures include the following: avoid dehydration, avoid CM when appropriate, minimize CM volume and frequency, avoid high osmolar CM, and discontinue nephrotoxic medications 48 hours before administration of CM.

Role of reactive oxygen species in pathogenesis of radiocontrast-induced nephropathy

In vitro and in vivo studies have demonstrated enhanced hypoxia and formation of reactive oxygen species (ROS) in the kidney following the administration of iodinated contrast media, which play a relevant role in the development of contrast media-induced nephropathy. Many studies indeed support this possibility, suggesting a protective effect of ROS scavenging or reduced ROS formation with the administration of N-acetylcysteine and bicarbonate infusion, respectively. Furthermore, most risk factors, predisposing to contrast-induced nephropathy, are prone to enhanced renal parenchymal hypoxia and ROS formation. In this review, the association of renal hypoxia and ROS-mediated injury is outlined. Generated during contrast-induced renal parenchymal hypoxia, ROS may exert direct tubular and vascular endothelial injury and might further intensify renal parenchymal hypoxia by virtue of endothelial dysfunction and dysregulation of tubular transport. Preventive strategies conceivably should include inhibition of ROS generation or ROS scavenging.

Role of renal biomarkers as predictors of acute kidney injury in cardiac surgery

Cardiac surgery is unique in using cardiopulmonary bypass in various clinical scenarios. Injury of vital organs is unavoidable in the perioperative period. Acute kidney injury is a consequence of the systemic inflammatory response after bypass, emboli, ischemia, and low cardiac output states, reportedly occurring in 30%–40% of open heart surgeries. Acute kidney injury is associated with increased morbidity, mortality, and cost. Many preventive measures (off-pump procedures, decreased crossclamp time, pulsatile flow, adequate hydration) are taken in the perioperative period to avoid organ injury, but in vain. Traditionally, blood urea, serum creatinine, and creatinine clearance rate were applied for prediction of acute kidney injury. The recent emergence of biomarkers such as neutrophil gelatinase-associated lipocalin, cystatin C, liver-type fatty acid binding protein, interleukin-18, kidney injury molecule-1, and tetrahydrobiopterin have helped in detecting acute kidney injury long before the rise of serum creatinine. These biomarkers can also be used as tools for predicting therapeutic effects in acute kidney injury and for monitoring drug toxicity. This review consolidates the knowledge of biomarkers and their application in acute kidney injury management.

Clinical predictors of contrast-induced acute kidney injury in patients undergoing emergency versus elective percutaneous coronary intervention

BACKGROUND

To evaluate the incidence and clinical predictors of contrast-induced acute kidney injury (CI-AKI) in patients with ST-segment elevation myocardial infarction (STEMI), unstable angina pectoris/non-STEMI (UAP/NSTEMI), and stable AP (SAP) undergoing percutaneous coronary intervention (PCI).

METHODS AND RESULTS

We enrolled 1,954 patients (SAP, n=1,222; UAP/NSTEMI, n=277; STEMI, n=455) who underwent PCI. Patients were categorized according to contrast media volume/estimated glomerular filtration rate ratio (CV/eGFR low: <2.0, mid: 2.0-2.9, high: ≥3.0). CI-AKI was defined as an increase in serum creatinine of 0.5mg/dl or 25% within 1 week from contrast-medium injection. The incidence of CI-AKI was highest among the STEMI patients (SAP, 4.24%; UAP/NSTEMI, 10.7%; STEMI, 16.1%, P<0.01). Significant predictors of CI-AKI were emergency PCI (odds ratio [OR] 3.70; 95% confidence interval [CI] 2.55-5.37; P<0.001), ejection fraction <40% (OR 2.04; 95% CI 1.24-3.36; P=0.005), and hemoglobin <10g/dl (OR 0.02; 95% CI 1.17-4.55; P=0.02) after multivariate logistic regression analysis. In the SAP group, a CV/eGFR ratio ≥3.0 was a significant predictor of CI-AKI (P=0.048), but not in UAP/NSTEMI and STEMI patients.

CONCLUSIONS

UAP/NSTEMI and STEMI patients undergoing emergency PCI were at high risk for CI-AKI regardless of CV/eGFR ratio. Minimizing the dose of contrast medium based on eGFR might be valuable in reducing the risk of CI-AKI in SAP patients.

Radiographic contrast-media-induced acute kidney injury: pathophysiology and prophylactic strategies

Contrast-induced acute kidney injury (CI-AKI) is one of the most widely discussed and debated topics in cardiovascular medicine. With increasing number of contrast-media- (CM-) enhanced imaging studies being performed and growing octogenarian population with significant comorbidities, incidence of CI-AKI remains high. In this review, pathophysiology of CI-AKI, its relationship with different types of CM, role of serum and urinary biomarkers for diagnosing CI-AKI, and various prophylactic strategies used for nephroprotection against CI-AKI are discussed in detail.

Bicarbonates for the prevention of postoperative renal failure in endovascular aortic aneurysm repair: a randomized pilot trial

Purpose. Contrast-induced nephropathy (CIN) can contribute to acute kidney injury (AKI) in patients undergoing endovascular aortic aneurysm surgery. We evaluated the incidence of AKI together with the evolution of early biomarkers of renal injury in patients receiving bicarbonates or NaCl 0.9%. Methods. This study involved endovascular aortic aneurysm surgery patients. Group A (n = 17) received bicarbonates 3 mL/kg/h for 1 h before the procedure and then 1 mL/kg/h until 6 h after surgery, whereas group B (n = 17) received NaCl 0.9% using the same protocol. Biomarkers of renal injury from urine (interleukin-18 (IL-18), neutrophil gelatinase-associated lipocalin (NGAL), N-acetyl-β-D-glucosaminidase (NAG), and kidney injury molecule 1 (KIM-1)) and blood (NGAL, cystatin C) were measured at baseline and 3, 24, and 48 h postoperatively. Results. AKI occurred in 1 patient (2.9%), in the bicarbonates group. IL-18, NAG, NGAL, and KIM-1 significantly rose in both groups after the surgery. There was a greater rise in NGAL and IL-18 after 3 h in the bicarbonates versus NaCl 0.9% group: 1115% versus 240% increase (P = 0.03) and 338% increase versus 1.4% decrease (P = 0.01). Conclusions. Despite significant elevation in biomarkers of renal injury, we demonstrated a low rate of AKI following endovascular aortic surgery.

N-acetylcysteine does not prevent contrast nephropathy in patients with renal impairment undergoing emergency CT: a randomized study

BACKGROUND

Patients admitted to the emergency room with renal impairment and undergoing a contrast computed tomography (CT) are at high risk of developing contrast nephropathy as emergency precludes sufficient hydration prior to contrast use. The value of an ultra-high dose of intravenous N-acetylcysteine in this setting is unknown.

METHODS

From 2008 to 2010, we randomized 120 consecutive patients admitted to the emergency room with an estimated clearance lower than 60 ml/min/1.73 m2 by MDRD (mean GFR 42 ml/min/1.73 m2) to either placebo or 6000 mg N-acetylcysteine iv one hour before contrast CT in addition to iv saline. Serum cystatin C and creatinine were measured one hour prior to and at day 2, 4 and 10 after contrast injection. Nephrotoxicity was defined either as 25% or 44 μmol/l increase in serum creatinine or cystatin C levels compared to baseline values.

RESULTS

Contrast nephrotoxicity occurred in 22% of patients who received placebo (13/58) and 27% of patients who received N-acetylcysteine (14/52, p = 0.66). Ultra-high dose intravenous N-acetylcysteine did not alter creatinine or cystatin C levels. No secondary effects were noted within the 2 groups during follow-up.

CONCLUSIONS

An ultra-high dose of intravenous N-acetylcysteine is ineffective at preventing nephrotoxicity in patients with renal impairment undergoing emergency contrast CT.

TRIAL REGISTRATION

The study was registered as Clinical trial (NCT01467154).