Effectiveness of N-Acetylcysteine for the Prevention of Contrast-Induced Nephropathy: A Systematic Review and Meta-Analysis of Randomized Controlled Trials

Evaluation of pathways involved in the protective effect of trans sodium crocetinate against contrast-induced nephropathy in rats

Contrast-induced nephropathy (CIN) is the most important side effect following contrast media application. The purpose of this study was to investigate the nephroprotective effects of trans sodium crocetinate (TSC) against sodium amidotrizoate/meglumine amidotrizoate (SAMA). Wistar rats were classified into eight groups (n = 6, male, 220-250 g) including (1) sham, injection of solvents (intraperitoneally; i.p.), (2) premedication-control, N(ω)-nitro-L-arginine methyl ester (L-NAME, 10 mg/kg, i.p.) + indomethacin (IND, 10 mg/kg, i.p.), (3) model (L-NAME + IND + SAMA (12.5 ml/kg, i.p.)), (4-6) TSC 10, 20, and 40 mg/kg/day, 7 days, i.p., and L-NAME + IND + SAMA, (7) N-acetylcysteine (NAC, 125 mg/kg/day, 7 days, i.p.) and L-NAME + IND + SAMA, (8) TSC alone (40 mg/kg/day, 7 days, i.p.). Rats were injected with L-NAME, IND, and SAMA 40 h after water deprivation. SAMA caused the enhancement of histopathological damage in kidney tissue, biochemical factors (serum blood urea nitrogen and creatinine), and oxidative stress. Moreover, SAMA increased inflammation (TNF-α), apoptosis proteins (Caspase 3-cleaved and Bax/Bcl-2 ratio), and autophagy markers (Beclin-1 and LC3 II/I ratio). TSC declined biochemical factors and oxidative stress. Also, TSC 40 mg/kg decreased histopathological damage, inflammation, apoptosis, and autophagy markers. This study demonstrated that TSC has nephroprotective effects through anti-oxidant, anti-inflammatory, and anti-apoptotic properties, as well as regulating autophagy.

Effect of high-dose N-acetyl cysteine on the clinical outcome of patients with diabetic peripheral neuropathy: a randomized controlled study

BACKGROUND

Diabetic peripheral neuropathy (DPN) is a vastly common and bothersome disorder with a clinically challenging course of treatment affecting patients with diabetes. This study aimed to evaluate the efficacy and safety of high dose oral N-acetyl cysteine (NAC) as adjuvant therapy on clinical outcome of DPN.

METHODS

A prospective, randomized, parallel, open label, controlled clinical trial. Ninety eligible DPN patients were randomly assigned to either control group receiving standard of care or NAC group receiving standard of care treatment and NAC at a dose of 2400 mg/day for 12 weeks. Glutathione peroxidase (GPx), nuclear factor erythoid-2 related factor (NRF-2) and tumor necrosis factor (TNF) were measured at baseline and after 12 weeks to assess anti-oxidant and anti-inflammatory properties. Michigan neuropathy screening instrument (MNSI), Toronto clinical neuropathy score (TCNS), Diabetic neuropathy score (DNS), Diabetes-39 quality of life questionnaire (DQOL) and pain score were assessed at baseline and after 12 weeks.

RESULTS

NAC group showed a significant increase (p < 0.05) in NRF-2 by 25.3% and GPx by 100% and a decline of 21.45% in TNF-alpha levels versus controls that reported a decline in NRF-2 and GPx and an increase in TNF-alpha. HgbA1C and AST levels significantly decreased in NAC versus controls (7.2 ± 1 vs 8 ± 1.1, p = 0.028 and 29.1 vs 55.4, p = 0.012) respectively. NAC administration resulted in a significant decline in MNSA, TCNS, DNS and pain scores versus controls that showed increase in all scores. The QOL total score and the anxiety and energy and mobility domain scores significantly decreased in the NAC group versus controls, p < 0.001.

CONCLUSION

High dose NAC administered for 12 weeks modulated inflammation by reducing TNF-alpha and increasing GPx and NRF2 versus controls. NAC improved clinical outcomes of DPN reflected by a decline in neuropathy and pain scores and an improvement in QOL.

CLINICAL TRIAL REGISTRATION NUMBER

NCT04766450.

Contrast-Induced Acute Kidney Injury in Radiology: Recent Insights and Advances

Contrast-induced acute kidney injury (CI-AKI) continues a critical concern in the realm of radiology, necessitating constant updates and insights to inform clinical practices. This comprehensive literature review explores the latest advancements and research trends surrounding CI-AKI, shedding light on its multifaceted complexities. By amalgamating the latest findings, this review not only enhances the current knowledge base but also acts as a guiding beacon for healthcare professionals. Ultimately, the insights presented here serve as a valuable resource, fostering continuous improvements in CI-AKI prevention, patient safety, and the overall efficacy of radiological interventions.

TRPA1 protects against contrast-induced renal tubular injury by preserving mitochondrial dynamics via the AMPK/DRP1 pathway

Mitochondrial dysfunction and oxidative stress are involved in the development of contrast-induced acute kidney injury (CI-AKI). The present study aimed to reveal the role of transient receptor potential ankyrin 1 (TRPA1), an oxidative sensor, in CI-AKI. Trpa1PT-/- mice with Trpa1 conditionally knocked out in renal proximal tubular (PT) cells, Trpa1 overexpression mice (Trpa1-OE), and TRPA1 agonists and antagonists were used to study its function in a mouse model of iohexol-induced CI-AKI. We found that TRPA1 was functionally expressed in PT cells. Activation of TRPA1 with cinnamaldehyde or overexpression of Trpa1 remarkably ameliorated renal tubular injury and dysfunction in a mouse model of CI-AKI, while CI-AKI was significantly exacerbated in Trpa1PT-/- mice. Proteomics demonstrated that mouse kidneys with CI-AKI had downregulated proteins involved in mitochondrial dynamics and upregulated mitophagy-associated proteins. The beneficial effects of TRPA1 activation/overexpression on CI-AKI were associated with improved mitochondrial function, decreased mitochondrial fission and oxidative stress, enhanced mitophagy, and less apoptosis of renal tubular cells. TRPA1-induced decreases in mitochondrial fission were linked to upregulated fusion-related proteins (mitofusin 1, mitofusin 2 and optic atrophy 1) and downregulated fission mediator, phosphorylated dynamin-related protein 1 (Drp1). Importantly, inhibition of Drp1 with mitochondrial division inhibitor 1 improved CI-AKI. In addition, the decreased mitochondrial fission was also mediated by inactivation of AMP-activated protein kinase which mediates mitochondrial biogenesis. The findings suggest that TRPA1 plays a protective role in CI-AKI through regulating mitochondrial fission/fusion, biogenesis, and dysfunction. Activating TRPA1 may become novel therapeutic strategies for the prevention of CI-AKI.

The oxidant-antioxidant imbalance was involved in the pathogenesis of chronic rhinosinusitis with nasal polyps

Background

Although oxidative stress is involved in the pathophysiological process of chronic rhinosinusitis with nasal polyps (CRSwNP), the specific underlying mechanism is still unclear. Whether antioxidant therapy can treat CRSwNP needs further investigation.

Methods

Immunohistochemistry, immunofluorescence, western blotting and quantitative polymerase chain reaction (qPCR) analyses were performed to detect the distribution and expression of oxidants and antioxidants in nasal polyp tissues. qPCR revealed correlations between oxidase, antioxidant enzymes and inflammatory cytokine levels in CRSwNP patients. Human nasal epithelial cells (HNEpCs) and primary macrophages were cultured to track the cellular origin of oxidative stress in nasal polyps(NPs) and to determine whether crocin can reduce cellular inflammation by increasing the cellular antioxidant capacity.

Results

The expression of NOS2, NOX1, HO-1 and SOD2 was increased in nasal epithelial cells and macrophages derived from nasal polyp tissue. Oxidase levels were positively correlated with those of inflammatory cytokines (IL-5 and IL-6). Conversely, the levels of antioxidant enzymes were negatively correlated with those of IL-13 and IFN-γ. Crocin inhibited M1 and M2 macrophage polarization as well as the expression of NOS2 and NOX1 and improved the antioxidant capacity of M2 macrophages. Moreover, crocin enhanced the ability of antioxidants to reduce inflammation via the KEAP1/NRF2/HO-1 pathway in HNEpCs treated with SEB or LPS. Additionally, we observed the antioxidant and anti-inflammatory effects of crocin in nasal explants.

Conclusion

Oxidative stress plays an important role in the development of CRSwNP by promoting various types of inflammation. The oxidative stress of nasal polyps comes from epithelial cells and macrophages. Antioxidant therapy may be a promising strategy for treating CRSwNP.

Adjunctive treatments for pneumococcal meningitis: a systematic review of experimental animal models

New treatments are needed to improve the prognosis of pneumococcal meningitis. We performed a systematic review on adjunctive treatments in animal models of pneumococcal meningitis in order to identify treatments with the most potential to progress to clinical trials. Studies testing therapy adjunctive to antibiotics in animal models of pneumococcal meningitis were included. A literature search was performed using Medline, Embase and Scopus for studies published from 1990 up to 17 February 2023. Two investigators screened studies for inclusion and independently extracted data. Treatment effect was assessed on the clinical parameters disease severity, hearing loss and cognitive impairment and the biological parameters inflammation, brain injury and bacterial load. Adjunctive treatments were evaluated by their effect on these outcomes and the quality, number and size of studies that investigated the treatments. Risk of bias was assessed with the SYRCLE risk of bias tool. A total of 58 of 2462 identified studies were included, which used 2703 experimental animals. Disease modelling was performed in rats (29 studies), rabbits (13 studies), mice (12 studies), gerbils (3 studies) or both rats and mice (1 study). Meningitis was induced by injection of Streptococcus pneumoniae into the subarachnoid space. Randomization of experimental groups was performed in 37 of 58 studies (64%) and 12 studies (12%) were investigator-blinded. Overall, 54 treatment regimens using 46 adjunctive drugs were evaluated: most commonly dexamethasone (16 studies), daptomycin (5 studies), complement component 5 (C5; 3 studies) antibody and Mn(III)tetrakis(4-benzoicacid)porphyrin chloride (MnTBAP; 3 studies). The most frequently evaluated outcome parameters were inflammation [32 studies (55%)] and brain injury [32 studies (55%)], followed by disease severity [30 studies (52%)], hearing loss [24 studies (41%)], bacterial load [18 studies (31%)] and cognitive impairment [9 studies (16%)]. Adjunctive therapy that improved clinical outcomes in multiple studies was dexamethasone (6 studies), C5 antibodies (3 studies) and daptomycin (3 studies). HMGB1 inhibitors, matrix metalloproteinase inhibitors, neurotrophins, antioxidants and paquinimod also improved clinical parameters but only in single or small studies. Evaluating the treatment effect of adjunctive therapy was complicated by study heterogeneity regarding the animal models used and outcomes reported. In conclusion, 24 of 54 treatment regimens (44%) tested improved clinically relevant outcomes in experimental pneumococcal meningitis but few were tested in multiple well-designed studies. The most promising new adjunctive treatments are with C5 antibodies or daptomycin, suggesting that these drugs could be tested in clinical trials.

Cysteine induces mitochondrial reductive stress in glioblastoma through hydrogen peroxide production

Glucose and amino acid metabolism are critical for glioblastoma (GBM) growth, but little is known about the specific metabolic alterations in GBM that are targetable with FDA-approved compounds. To investigate tumor metabolism signatures unique to GBM, we interrogated The Cancer Genome Atlas for alterations in glucose and amino acid signatures in GBM relative to other human cancers and found that GBM exhibits the highest levels of cysteine and methionine pathway gene expression of 32 human cancers. Treatment of patient-derived GBM cells with the FDA-approved single cysteine compound N-acetylcysteine (NAC) reduced GBM cell growth and mitochondrial oxygen consumption, which was worsened by glucose starvation. Normal brain cells and other cancer cells showed no response to NAC. Mechanistic experiments revealed that cysteine compounds induce rapid mitochondrial H2O2 production and reductive stress in GBM cells, an effect blocked by oxidized glutathione, thioredoxin, and redox enzyme overexpression. From analysis of the clinical proteomic tumor analysis consortium (CPTAC) database, we found that GBM cells exhibit lower expression of mitochondrial redox enzymes than four other cancers whose proteomic data are available in CPTAC. Knockdown of mitochondrial thioredoxin-2 in lung cancer cells induced NAC susceptibility, indicating the importance of mitochondrial redox enzyme expression in mitigating reductive stress. Intraperitoneal treatment of mice bearing orthotopic GBM xenografts with a two-cysteine peptide induced H2O2 in brain tumors in vivo. These findings indicate that GBM is uniquely susceptible to NAC-driven reductive stress and could synergize with glucose-lowering treatments for GBM.

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].

Endogenous and Exogenous Antioxidants as Agents Preventing the Negative Effects of Contrast Media (Contrast-Induced Nephropathy)

The use of conventional contrast media for diagnostic purposes (in particular, Gd-containing and iodinated agents) causes a large number of complications, the most common of which is contrast-induced nephropathy. It has been shown that after exposure to contrast agents, oxidative stress often occurs in patients, especially in people suffering from various diseases. Antioxidants in the human body can diminish the pathological consequences of the use of contrast media by suppressing oxidative stress. This review considers the research studies on the role of antioxidants in preventing the negative consequences of the use of contrast agents in diagnostics (mainly contrast-induced nephropathy) and the clinical trials of different antioxidant drugs against contrast-induced nephropathy. Composite antioxidant/contrast systems as theranostic agents are also considered.

Incomplete Recovery from the Radiocontrast-Induced Dysregulated Cell Cycle, Adhesion, and Fibrogenesis in Renal Tubular Cells after Radiocontrast (Iohexol) Removal

Contrast-induced nephropathy (CIN) is one of the most common causes of acute kidney injury (AKI). However, management is still limited, and the cellular response to radiocontrast removal for CIN remains unclear. This study aimed to explore the latent effects of iohexol in cultured renal tubular cells with or without the removal of iohexol by medium replacement. HK2 renal tubular cells were subcultured 24 h before use in CIN experiments. Three treatment groups were established: the control, a radiocontrast (iohexol)-only group at 75 mg I/mL (I-75), and iohexol exposure for 24 h with culture medium replacement (I-75/M). Cell cycle arrest, fibrogenic mediator assays, cell viability, cell function, and cell-cycle-related protein expression were compared between groups. Iohexol induced numerous changes in HK2 renal tubular cells, such as enlarged cell shape, cell cycle arrest, increased apoptosis, and polyploidy. Iohexol inhibited the expression of cyclins, CDKs, ZO-1, and E-cadherin but conversely enhanced the expression of p21 and fibrosis-related genes, including TGF-β1, CTGF, collagen I, collagen III, and HIF-1α within 60 hr after the exposure. Except for the recovery from cell cycle arrest and cell cycle gene expression, notably, the removal of iohexol by medium replacement could not fully recover the renal tubular cells from the formation of polyploid cells, the adhesion or spreading, or the expression of fibrosis-related genes. The present study demonstrates, for the first time, that iohexol exerts latent cytotoxic effects on cultured renal tubular cells after its removal, suggesting that these irreversible cell changes may cause the insufficiency of radiocontrast reduction in CIN, which is worth investigating further.

Targeting Mitochondrial Oxidative Stress as a Strategy to Treat Aging and Age-Related Diseases

Mitochondria are one of the organelles undergoing rapid alteration during the senescence process. Senescent cells show an increase in mitochondrial size, which is attributed to the accumulation of defective mitochondria, which causes mitochondrial oxidative stress. Defective mitochondria are also targets of mitochondrial oxidative stress, and the vicious cycle between defective mitochondria and mitochondrial oxidative stress contributes to the onset and development of aging and age-related diseases. Based on the findings, strategies to reduce mitochondrial oxidative stress have been suggested for the effective treatment of aging and age-related diseases. In this article, we discuss mitochondrial alterations and the consequent increase in mitochondrial oxidative stress. Then, the causal role of mitochondrial oxidative stress on aging is investigated by examining how aging and age-related diseases are exacerbated by induced stress. Furthermore, we assess the importance of targeting mitochondrial oxidative stress for the regulation of aging and suggest different therapeutic strategies to reduce mitochondrial oxidative stress. Therefore, this review will not only shed light on a new perspective on the role of mitochondrial oxidative stress in aging but also provide effective therapeutic strategies for the treatment of aging and age-related diseases through the regulation of mitochondrial oxidative stress.

Contrast-induced acute kidney injury and its contemporary prevention

The complexity and application range of interventional and diagnostic procedures using contrast media (CM) have recently increased. This allows more patients to undergo procedures that involve CM administration. However, the intrinsic CM toxicity leads to the risk of contrast-induced acute kidney injury (CI-AKI). At present, effective therapy of CI-AKI is rather limited. Effective prevention of CI-AKI therefore becomes crucially important. This review presents an in-depth discussion of CI-AKI incidence, pathogenesis, risk prediction, current preventive strategies, and novel treatment possibilities. The review also discusses the difference between CI-AKI incidence following intraarterial and intravenous CM administration. Factors contributing to the development of CI-AKI are considered in conjunction with the mechanism of acute kidney damage. The need for ultimate risk estimation and the prediction of CI-AKI is stressed. Possibilities of CI-AKI prevention is evaluated within the spectrum of existing preventive measures aimed at reducing kidney injury. In particular, the review discusses intravenous hydration regimes and pre-treatment with statins and N-acetylcysteine. The review further focuses on emerging alternative imaging technologies, alternative intravascular diagnostic and interventional procedures, and new methods for intravenous hydration guidance; it discusses the applicability of those techniques in complex procedures and their feasibility in current practise. We put emphasis on contemporary interventional cardiology imaging methods, with a brief discussion of CI-AKI in non-vascular and non-cardiologic imaging and interventional studies.

The role of oxidative stress in the development of knee osteoarthritis: A comprehensive research review

Knee osteoarthritis (KOA) is one of the most common degenerative diseases, and its core feature is the degeneration and damage of articular cartilage. The cartilage degeneration of KOA is due to the destruction of dynamic balance caused by the activation of chondrocytes by various factors, with oxidative stress playing an important role in the pathogenesis of KOA. The overproduction of reactive oxygen species (ROS) is a result of oxidative stress, which is caused by a redox process that goes awry in the inherent antioxidant defence system of the human body. Superoxide dismutase (SOD) inside and outside chondrocytes plays a key role in regulating ROS in cartilage. Additionally, synovitis is a key factor in the development of KOA. In an inflammatory environment, hypoxia in synovial cells leads to mitochondrial damage, which leads to an increase in ROS levels, which further aggravates synovitis. In addition, oxidative stress significantly accelerates the telomere shortening and ageing of chondrocytes, while ageing promotes the development of KOA, damages the regulation of redox of mitochondria in cartilage, and stimulates ROS production to further aggravate KOA. At present, there are many drugs to regulate the level of ROS, but these drugs still need to be developed and verified in animal models of KOA. We discuss mainly how oxidative stress plays a part in the development of KOA. Although the current research has achieved some results, more research is needed.

Prevention and Management of AKI in ACS Patients Undergoing Invasive Treatments

PURPOSE OF REVIEW

Management of patients presenting with acute coronary syndrome (ACS) includes invasive procedures that may increase the risk of acute kidney injury (AKI). AKI adversely affects the outcomes of such procedures and complicates the management of ACS. We have summarized several strategies for the prevention and management of AKI in this critical patient group including in the pre-procedural, intraprocedural, and post-procedural settings.

RECENT FINDINGS

Definitive prevention and management strategies for AKI in patients presenting with ACS requiring invasive management can be confounded by the variation in data outcomes. Pre-procedural hydration with normal saline when accounting for time to catheterization, radial artery access, contrast stewardship, and close monitoring of renal function after catheterization should be implemented.

Contrast-Associated Acute Kidney Injury

Contrast-associated acute kidney injury (CA-AKI) is an impairment of renal function, which occurs within days of intravascular administration of iodinated contrast media. Taking into account that minimally invasive cardiac interventions are becoming increasingly popular, compared to traditional surgery, given their impact on prognosis and costs, CA-AKI remains a subject of increasing interest for patients and physicians. This review summarizes the epidemiology and risk stratification, diagnostic criteria, pathophysiology and clinical implications of CA-AKI, providing evidence for the most studied preventive strategies.

Prospective randomized comparison of effect on coronary endothelial and renal function between febuxostat and benzbromarone in hyperuricemic patients with coronary artery disease: EFEF study

Background and Aims

There are two types of serum uric acid-lowering agents, the xanthine oxidoreductase (XO) inhibitor and non-XO inhibitor. We investigated whether febuxostat, XO inhibitor, could produce more favorable effects on coronary endothelial function (CEF) and renal function than benzbromarone, non-XO inhibitor, in hyperuricemic coronary artery disease (CAD) patients.

Methods

We divided 21 hyperuricemic patients with stenting for left anterior descending (LAD) or left circumflex (LCX) artery into patients started on febuxostat (F group) and those on benzbromarone (B group). After 8 months, all patients underwent CEF evaluations (acetylcholine provocation test) and optical coherence tomography (OCT) for non-culprit vessels (e.g. if patients received LAD stenting, we evaluated LCX). We compared the diameter ratio induced by acetylcholine and baseline (CEF ratio), thin-cap fibroatheroma and calcified plaque by OCT, uric acid, oxidative stress biomarkers, and renal function including estimated glomerular filtration rate (eGFR) between F and B groups. Creatinine 2 days after stenting was measured to evaluate contrast-induced nephropathy (CIN).

Results

Change of eGFR was significantly lower in F group (n= 11) than B group over 8 months while the other parameters including CEF ratio were similar. F group showed favorable effects for CIN.

Conclusion

In conclusion, 8-months of febuxostat, XO inhibitor, does not significantly protect CEF but can protect the renal function including CIN in hyperuricemic patients with CAD compared to benzbromarone, non-XO inhibitor.

Analysis of Risk Factors for Perioperative Acute Kidney Injury and Management Strategies

Acute kidney injury (AKI) is a serious clinical syndrome, and one of the common comorbidities in the perioperative period. AKI can lead to complications in surgical patients and is receiving increasing attention in clinical workup. In recent years, the analysis of perioperative risk factors has become more in-depth and detailed. In this review, the definition, diagnosis, and pathophysiological characteristics of perioperative AKI are reviewed, and the main risk factors for perioperative AKI are analyzed, including advanced age, gender, certain underlying diseases, impaired clinical status such as preoperative creatinine levels, and drugs that may impair renal function such as non-steroidal anti-inflammatory drugs (NASIDs), ACEI/ARB, and some antibiotics. Injectable contrast agents, some anesthetic drugs, specific surgical interventions, anemia, blood transfusions, hyperglycemia, and malnutrition are also highlighted. We also propose potential preventive and curative measures, including the inclusion of renal risk confirmation in the preoperative assessment, minimization of intraoperative renal toxin exposure, intraoperative management and hemodynamic optimization, remote ischemic preadaptation, glycemic control, and nutritional support. Among the management measures, we emphasize the need for careful perioperative clinical examination, timely detection and management of AKI complications, administration of dexmedetomidine for renal protection, and renal replacement therapy. We aim that this review can further increase clinicians' attention to perioperative AKI, early assessment and intervention to try to reduce the risk of AKI.

Efficacy and safety of acetylcysteine for the prevention of liver injury in COVID-19 intensive care unit patients under treatment with remdesivir

AIM

The present double-blinded placebo-controlled randomized clinical trial evaluated prophylactic use of acetylcysteine for the prevention of liver injury in patients with severe COVID-19 pneumonia under treatment with remdesivir.

BACKGROUND

Liver injury is reportedly common in patients with severe COVID-19 pneumonia and can occur not only as a result of disease progression, but as an iatrogenic reaction to remdesivir.

METHODS

A total of 83 adult patients with severe COVID-19 pneumonia were randomly assigned in parallel groups to receive either acetylcysteine or placebo. All the patients received standard care according to institutional protocols, including remdesivir for a total of five days. One gram acetylcysteine was administered intravenously every 12 hours for 42 patients, and 41 patients received the same volume of 0.9% sodium chloride as placebo (Trial Registration: www.irct.ir identifier, IRCT20210726051995N1).

RESULTS

After 5 days, median aspartate transaminase (AST) and alanine transaminase (ALT) levels were significantly lower in the acetylcysteine than in the placebo group. Of those who received the placebo, 30 (73.2%), 4 (9.7%), and 3 (7.3%) patients had serum AST levels elevated between 1-2.5, 2.5-5, and over 5 times the upper limit of normal (ULN), respectively; while in the acetylcysteine group, 33 (78.6%) and 0 patients had AST levels between 1-2.5 and over 2.5 times ULN, respectively (p-value=0.037). In the acetylcysteine group, 23 (54.8%), 1 (2.4%), and 1 (2.4%) patient had serum ALT levels elevated between 1-2.5, 2.5-5, and over 5 times ULN, respectively; in the placebo group, however, 24 (58.5%), 7 (17.1%), and 1 (2.4%) patient had serum ALT levels between 1-2.5, 2.5-5, and over 5 times ULN, respectively (p-value=0.073).

CONCLUSION

Intravenous administration of acetylcysteine significantly prevents liver transaminases elevation and liver injury in seriously ill COVID-19 patients treated with remdesivir.

N-Acetylcysteine's Renoprotective Effect in Cardiac Surgery: A Systematic Review and Meta-Analysis

OBJECTIVE

To examine N-acetylcysteine's (NAC's) renoprotective effect in adult cardiac surgeryMethods: PubMed, Ovid Medline, and Embase were searched for randomized controlled trials published between January 1990 and May 2021 that investigated the effect of NAC in preventing acute kidney injury (AKI) in patients undergoing cardiac surgery. The inclusion criterion was studies that assessed the effect of NAC in comparison to placebo by measuring the incidence of AKI.

RESULTS

Overall meta-analytic estimates of all 10 included trials showed that NAC did not have a significant effect (odds ratio [OR]: 0.84, 95% confidence interval [CI]: 0.64-1.10) on AKI. Further subgroup analysis did not show a significant benefit of NAC in preventing AKI.

CONCLUSION

This meta-analysis suggests that NAC does not have a significant effect in reducing the incidence of AKI. However, there is notable heterogeneity among the included studies that could possibly account for the non-significant effect observed. It is worth noting that only one trial administered NAC high dosages perioperatively, and it is the only included trial to show a significant benefit in reducing the incidence of AKI (OR: 0.30, 95% CI: 0.11-0.81). Further studies on this dosage and duration of administration should be conducted to best elucidate the effect of administering NAC.

Contrast associated nephropathy after intravenous administration: what is the magnitude of the problem?

Intravenous contrast media (CM) is often used in clinical practice to enhance CT scan imaging. For many years, contrast-induced nephropathy (CIN) was thought to be a common occurrence and to result in dire consequences. When treating patients with abnormal renal function, it is not unusual that clinicians postpone, cancel, or replace contrast-enhanced imaging with other, perhaps less informative tests. New studies however have challenged this paradigm and the true risk attributable to intravenous CM for the occurrence of CIN has become debatable. In this article, we review the latest relevant medical literature and aim to provide an evidence-based answer to questions surrounding the risk, outcomes, and potential mitigation strategies of CIN after intravenous CM administration.

Targeting oxidative stress in disease: promise and limitations of antioxidant therapy

Oxidative stress is a component of many diseases, including atherosclerosis, chronic obstructive pulmonary disease, Alzheimer disease and cancer. Although numerous small molecules evaluated as antioxidants have exhibited therapeutic potential in preclinical studies, clinical trial results have been disappointing. A greater understanding of the mechanisms through which antioxidants act and where and when they are effective may provide a rational approach that leads to greater pharmacological success. Here, we review the relationships between oxidative stress, redox signalling and disease, the mechanisms through which oxidative stress can contribute to pathology, how antioxidant defences work, what limits their effectiveness and how antioxidant defences can be increased through physiological signalling, dietary components and potential pharmaceutical intervention.

The effect of N-acetyl cysteine injection on renal function after coronary artery bypass graft surgery: a randomized double blind clinical trial

BACKGROUND

This study aimed to compare the effects of N-acetyl cysteine on renal function after coronary artery bypass graft surgery.

METHODS

In this randomized clinical trial conducted in Golestan Hospital, Ahvaz, Iran, 60 candidates for coronary artery bypass graft surgery were selected and divided into two N-acetyl cysteine and control groups (30 people each). Patients received 3 (2 intraoperative and 1 postoperative) doses of IV N-acetyl cysteine (100 mg/kg) (n = 30) or placebo (n = 30) over 24 h. Prescription times were as follows: after induction of anesthesia, in the Next 4 h, and in the 16 h after on. Primary outcomes were serum levels of BUN and Cr, at baseline,4 and 48 h after surgery. And also need renal replacement therapy (RRT). Secondary outcomes included the hemodynamic variables, Blood products transfusion.

RESULTS

There were significant differences in BUN between groups at 4 h (P = 0.02) and 48 h after surgery (P = 0.001) There were significant differences in Cr level between groups at 4 h (P < 0.001) and 48 h after surgery (P = 0.001). MAP at different times (at 4 h p = 0.002 and 48 h after surgery P < 0.001) were significantly different between the two groups. There was a significant difference between the two groups in terms of the unit of Packed cell transfusion (P = 0.002) and FFP transfusion (P < 0.001).

CONCLUSION

In the present study, we found that administration of N-acetyl cysteine can reduce the incidence of acute kidney injury in patients undergoing coronary artery bypass graft surgery and improved kidney functions.

TRIAL REGISTRY

IRCT20190506043492N3 Registered at 2020.06.07.

Impact of Supplementation with Omega-3 in the Prevention of Contrast-Induced Nephropathy Following Elective Percutaneous Coronary Intervention in Patients with Chronic Kidney Disease: A Randomized Placebo-Controlled Trial

Background:

Anti-oxidants were investigated in several studies as a preventive strategy for prevention of contrast-induced nephropathy (CIN). Omega-3 polyunsaturated fatty acids have antioxidant properties; however, their role in the prevention of CIN is still unknown. Therefore, in this study, we aimed to evaluate the efficacy of omega-3 supplementation in the prevention of contrast-induced nephropathy following elective percutaneous coronary intervention in patients with chronic kidney disease.

Methods:

This is a double-blinded and randomized clinical trial. Eighty eligible patients with glomerular filtration rate of 30-60 mL/min/1.73 m², scheduled to undergo elective PCI, were randomly divided into omega-3 (a single dose of 2500 mg omega-3 12 hours before PCI plus hydration therapy) or control (placebo plus hydration therapy) groups. Blood specimens for measuring serum creatinine and cystatin C were collected from each patient at baseline and 24 h after PCI.

Results:

Omega-3 did not show any significant effect on post-PCI serum creatinine and cystatin C compared to the controls. In addition, serum creatinine analysis showed that CIN occurred in 6 (16.2%) patients of the omega-3 and 4 (9.3%) patients of the control group (P = 0.50).

Conclusions:

Our results could not support the protective effect of a single dose of omega-3 in decreasing serum creatinine, serum cystatin C, and the incidence of CIN in patients with CKD undergoing PCI. To better evaluate the effect of omega-3, future studies with higher and/or multiple doses of omega-3 are highly recommended.

[ESUR recommendations on the use of contrast media: Practice survey, review and commentary by CJN, FIRN and SFNDT]

Contrast media administration is classically considered to cause or worsen kidney failure. Recent data may moderate this assertion. The European Society of Urogenital Radiology recently published guidelines re-evaluating the precautions before administering contrast media. The present work evaluates the practice of French nephrologists, and provides a commentary on these recommendations based on an updated review of the literature. We conducted survey among French nephrologists, using an electronic questionnaire distributed by the Société Francophone de Néphrologie, Dialyse et Transplantation, the French Intensive care Renal Network and the Club des Jeunes Néphrologues. 266 responses were collected. The European Society of Urogenital Radiology guidelines are poorly known among the panel of nephrologists. Their practices differ from the guidelines by the more frequent and earlier implementation of measures to prevent renal failure post contrast media. In accordance with the guidelines, hydration is prescribed as a first-line preventive measure, mainly with saline and bicarbonate. Inhibitors of the renin-angiotensin-aldosterone system are frequently discontinued before an injection of contrast media, contrary to what is recommended. In conclusion, the European Society of Urogenital Radiology guidelines, which the working group endorses, but which are still too little known and applied in clinical nephrology in France, prompt nephrologists to lift some of the restrictions on the use of PCI as well as on the continuation of ARS inhibitors before injecting PCI.

Kidney and contrast media: Common viewpoint of the French Nephrology societies (SFNDT, FIRN, CJN) and the French Radiological Society (SFR) following ESUR guidelines

Contrast medium administration is classically considered to cause or worsen kidney failure, but recent data may moderate this assertion. The European Society of Urogenital Radiology recently published guidelines re-evaluating the precautions before administering contrast media. Kidney injury does not constitute a contra-indication to the administration of iodinated contrast medium, as long as the benefit-risk ratio justifies it. Intravenous hydration with 0.9% NaCl or 1.4% sodium bicarbonate is the only validated measure for the prevention of post-iodine contrast nephropathy. This is necessary for intravenous or intra-arterial administration of iodinated contrast agent without first renal pass when the glomerular filtration rate is less than 30mL/min/1.73m², for intra-arterial administration of iodinated contrast agent with first renal passage when the glomerular filtration rate is less than 45mL/min/1.73m², or in patients with acute renal failure. The use of iodinated contrast medium should allow the carrying out of relevant examinations based on an analysis of the benefit-risk ratio and the implementation of measures to prevent toxicity when necessary.

Comparison of Oral and Intravenous N-acetyl Cysteine in Preventing Contrast Nephropathy

Introduction

Despite high rates of morbidity and mortality in patients with contrast-induced nephropathy (CIN), there is no consensus regarding prevention of this well-known complication of contrast media use. One agent that has been widely used in this regard is N-acetyl cysteine (NAC). Nevertheless, its efficacy is still controversial. The aim of this study was to assess the efficacy of NAC, both in the oral and intravenous forms, for the prevention of CIN.

Methods

This study is a double-blind randomized placebo controlled clinical trial. We randomized 434 adult patients with chronic kidney disease (constant serum creatinine ≥1.5 mg/dL) who were candidates for coronary angiography/plasty. The patients were categorized into three groups. One group received 1,200 mg NAC intravenously half an hour before the procedure and oral placebo starting 3 days before angiography. The second group received oral NAC 600 mg twice daily for 3 days, starting the day before the intervention and intravenous placebo half an hour before intervention. The third group received both oral and intravenous placebo. CIN was defined as a 25% relative increase in serum creatinine from baseline value, 48 h after use of contrast medium.

Results

Of the 434 patients, 149 received intravenous NAC, 145 received oral NAC, and the remaining 140 received placebo. The incidence of CIN in the three groups was 6.1%, 7.6%, and 10.8%, respectively (p = 0.34).

Conclusion

In patients with chronic kidney disease, neither intravenous nor oral NAC is superior to placebo for preventing CIN.

Iodinated contrast medium: Is there a re(n)al problem? A clinical vignette-based review

As we were taught, for decades, that iodinated contrast-induced acute kidney injury should be dreaded, considerable efforts were made to find out effective measures in mitigating the renal risk of iodinated contrast media. Imaging procedures were frequently either downgraded (unenhanced imaging) or deferred as clinicians felt that the renal risk pertaining to contrast administration outweighed the benefits of an enhanced imaging. However, could we have missed the point? Among the abundant literature about iodinated contrast-associated acute kidney injury, recent meaningful advances may help sort out facts from false beliefs. Hence, there is increasing evidence that the nephrotoxicity directly attributable to modern iodinated CM has been exaggerated. Failure to demonstrate a clear benefit from most of the tested prophylactic measures might be an indirect consequence. However, the toxic potential of iodinated contrast media is well established experimentally and should not be overlooked completely when making clinical decisions. We herein review these advances in disease and pathophysiologic understanding and the associated clinical crossroads through a typical case vignette in the critical care setting.

Latest Clinical Evidence About Effect of Acetylcysteine on Preventing Contrast-Induced Nephropathy in Patients Undergoing Angiography: A Meta-Analysis

Contrast-induced nephropathy (CIN) is a serious complication of angiographic procedures. It is the third most common cause of hospital acquired acute renal injury. As there are currently no approved therapies for CIN, prevention could be the best strategy to address this issue. Acetylcysteine may indirectly play an antioxidant role by inducing the synthesis of glutathione. Acetylcysteine can also reduce renal vasoconstriction induced by contrast medium stimulation by stabilizing nitric oxide and acting directly or indirectly on renal cortex and medulla microcirculation. To evaluate the effect of acetylcysteine on the prevention of CIN in patients after angiography, we systematically searched and analyzed the clinical data of patients including the incidence of CIN and change in serum creatinine (SCr) at 48 hours after angiography from selected articles. The result showed that acetylcysteine significantly reduces the incidence of CIN (risk ratios: 0.78, 95% CI: 0.68-0.90, I ² = 37.3%) and the level of SCr (standardized mean difference: -0.53, 95% CI: -0.93 to -0.12, I ² = 91.5%) after angiography compared with the control group. Overall, the use of acetylcysteine in patients after angiography was associated with a significant reduction of CIN and the level of SCr.

Risk Factors Associated With Contrast-Induced Nephropathy after Primary Percutaneous Coronary Intervention

Background Contrast-induced nephropathy (CIN) after primary percutaneous coronary intervention (PCI) is associated with increased mortality and morbidity. The aim of this study is to determine the frequency of CIN after primary PCI and its association with risk factors in patients with ST-segment elevation myocardial infarction (STEMI) at a tertiary care cardiac center in Pakistan. Methodology In this observational study, we included 282 patients who presented with STEMI and underwent primary PCI at the National Institute of Cardiovascular Disease, Karachi, Pakistan, from October 2017 to April 2018. The serum creatinine (mg/dL) levels were obtained at baseline and 48 to 72 hours after the primary PCI procedure, and patients with a 25% increase or ≥ 0.5 mg/dL rise in post-procedure creatinine level (after 48 to 72 hour) were categorized for CIN. Results Out of a total sample of 282 patients, 68.4% (193) were males, and the mean age was 56.4 ± 9.1 years. A majority of the patients, 78.7% (222), were hypertensive and 34% (96) were diabetic. The CIN was observed in 13.1% (37) of the patients, and increased risk of CIN was found to be associated with the presence of diabetes mellitus and increased (>200 mL) use of contrast during the procedure, with odds ratios of 2.3 (1.14-4.63) and 3.12 (1.36-7.17), respectively. Conclusions The CIN after PCI is a common complication associated with the presence of diabetes mellitus and the use of an increased amount of contrast during the procedure.

Phosphodiesterase-5 inhibitors ameliorate structural kidney damage in a rat model of contrast-induced nephropathy

The aim of the study was to investigate the potential of sildenafil and tadalafil to ameliorate structural kidney damage in contrast-induced nephropathy (CIN). A rat model of CIN was developed by dehydration, administration of a nitric oxide inhibitor and a prostaglandin synthesis inhibitor (L-NAME/indomethacin) and contrast media exposure to iopromide. The effect of pre-treatment with sildenafil, tadalafil or N-acetyl cysteine (NAC) for 7 days prior to CIN induction was investigated. All animals were sacrificed at 24 h after CIN induction and both kidneys were collected. Histopathological examination was performed under light microscopy in serial tissue sections stained with hematoxylin and eosin. CIN group showed hydropic changes of the renal tubules (proximal and distal convoluted tubules and Henle's loop), an increased Bowman space with lobulated glomerulus and alteration of macula densa region of distal convolute tubules. The groups pretreated with sildenafil and tadalafil showed nearly normal histological aspects of renal tissue. The group pretreated with NAC showed similar but less intense histopathologic changes compared to CIN group. Sildenafil and tadalafil pre-treatment ameliorates CIN-related structural kidney damage and the protective potential of these agents is superior to NAC.

Anti-Apoptotic and Antioxidant Effects of 3-Epi-Iso-Seco-Tanapartholide Isolated from Artemisia Argyi Against Iodixanol-Induced Kidney Epithelial Cell Death

Iodixanol is a non-ionic iso-osmolar contrast agent, but it is a risk factor for kidney damage and increases morbidity and mortality. In this study, we investigated the effect of 9 sesquiterpenes isolated from mugwort (Artemisia argyi) in contrast agent-induced cytotoxicity in LLC-PK1 cells. Cells were exposed to nine sesquiterpene compounds for 2 h, followed by incubation with iodixanol for 3 h. Cell viability was assessed using the Ez-Cytox assay. The level of reactive oxygen species was measured using 2′,7′-dichlorodihydrofluorescein diacetate staining. Apoptotic cell death was detected using annexin V/PI staining. In addition, immunofluorescence staining and western blotting were performed using antibodies against proteins related to apoptosis, oxidative stress, and MAPK pathways. The most effective 3-epi-iso-seco-tanapartholide (compound 8) among the 9 sesquiterpene compounds protected LLC-PK1 cells from iodixanol-induced cytotoxicity, oxidative stress, and apoptotic cell death. Pretreatment with compound 8 reversed iodixanol-induced increases in the expression of JNK, ERK, p38, Bax, caspase-3, and caspase-9. It also reversed the iodixanol-induced decrease in Bcl-2 expression. Furthermore, pretreatment with compound 8 caused nuclear translocation of Nrf2 and upregulated HO-1 via the Nrf2 pathway in iodixanol-treated LLC-PK1 cells. Thus, we demonstrated here that compound 8 isolated from A. argyi has the potential to effectively prevent iodixanol-induced kidney epithelial cell death via the caspase-3/MAPK pathways and HO-1 via the Nrf2 pathway.

Risk of acute kidney injury after contrast-enhanced computed tomography in emergency department

Background:

Despite its risks associated with renal injury, intravenous contrast media increases diagnostic efficacy and hence the chance of early diagnosis and treatment, which leaves clinicians in a dilemma regarding its use in emergency settings.

Objective:

The aim of this study was to determine the risk and predictors of contrast-induced acute kidney injury following intravenous contrast media administration for computed tomography in the emergency department.

Methods:

All patients aged 18 years and older who had a basal creatinine measurement within the last 8 h before contrast-enhanced computed tomography and a second creatinine measurement within 48–72 h after computed tomography scan between 1 January 2015 and 31 December 2017 were included in the study. Characteristics of patients with and without contrast-induced acute kidney injury development were compared. Multivariate regression analysis was used to assess the predictors for contrast-induced acute kidney injury.

Results:

A total of 631 patients were included in the final statistical analysis. After contrast media administration, contrast-induced acute kidney injury developed in 4.9% ( n = 31) of the patients. When the characteristics of patients are compared according to the development of contrast-induced acute kidney injury, significant differences were detected for age, initial creatinine, initial estimated glomerular filtration rate, and all acute illness severity indicators (hypotension, anemia, hypoalbuminemia, and need for intensive care unit admission). A multivariate logistic regression analysis was performed. The need for intensive care unit admission (odds ratio: 6.413 (95% confidence interval: 1.709–24.074)) and hypotension (odds ratio: 5.575 (95% confidence interval: 1.624–19.133)) were the main factors for contrast-induced acute kidney injury development.

Conclusion:

Our study results revealed that hypotension, need for intensive care, and advanced age were associated with acute kidney injury in patients receiving contrast media. Therefore, we believe that to perform contrast-enhanced computed tomography in emergency department should not be decided only by checking for renal function tests and that these predictors should be taken into consideration.

Efficacy of Oral Nicorandil to Prevent Contrast-Induced Nephropathy in Patients with Chronic Renal Dysfunction Undergoing an Elective Coronary Procedure

Objectives: This prospective, randomized study was to investigate the role of nicorandil in the prevention of contrast-induced nephropathy (CIN) in patients with chronic renal dysfunction undergoing an elective coronary procedure. Methods: A total of 252 eligible patients were enrolled in this study and allocated into the control group (n = 125) or nicorandil group (n = 127). Both groups received the standard hydration treatment, and patients in the nicorandil group were orally administrated 10 mg of nicorandil (t.i.d.) beginning 2 days before and continuing for 2 days after an elective coronary procedure. Serum creatinine (SCr) and cystatin C (CysC) were measured at 24 h before and 24, 48, and 72 h after the procedure. The occurrences of CIN and adverse events within 1 year were recorded. Results: The nicorandil group had relatively lower SCr and CysC levels and a higher eGFR at 24 and 48 h after the procedure than the control group (p < 0.05). The incidence of CIN was significantly decreased in the nicorandil group compared to the control group. The multivariate logistic regression model revealed that nicorandil treatment was an independent protective factor for CIN (OR 0.669, 95% CI 0.522–0.857, p = 0.001). The multivariate COX proportional hazard model showed that nicorandil treatment was an independent protective predictor for adverse events (HR 0.881, 95% CI 0.781–0.993, p = 0.037). Conclusions: Nicorandil could exhibit a protective effect against CIN in patients with chronic renal dysfunction undergoing an elective coronary procedure and reduce the adverse events within 1 year after the procedure, which is superior to hydration treatment only.

Intra-arterial catheter-directed CT angiography for assessment of endovascular aortic aneurysm repair

OBJECTIVE

To compare the efficacy and safety as well as associated image quality of catheter-directed CT angiography (CCTA) with a low dose of iodine contrast agent compared to intravenous CTA in patients undergoing endovascular aortic aneurysm repair (EVAR).

METHODS

Retrospective data analysis of 92 patients undergoing EVAR between January 2009 and December 2017 was performed. Patients were divided in two groups; those receiving CTA (n = 59) after intravenous contrast agent application and those receiving CCTA (n = 33) via an intraarterial catheter placed in the descending aorta. Demographic and cardiovascular risk factors as well as renal function parameters before, immediately after and 6-60 months after EVAR were evaluated. As primary endpoint, changes in serum creatinine levels in the two groups were evaluated. Secondary endpoints encompassed complications associated with intraarterial catheter placement. Objective (signal-to-noise ratios) and subjective image quality (5-point Likert scale) were compared.

RESULTS

Amount of contrast medium was significantly lower in CCTA compared to i.v. CTA (23 ± 7 ml vs. 119 ± 15 ml, p<0.0001). Patients undergoing catheter-directed CTA had higher baseline creatinine values compared to the group with intravenous iodine application (1.9 ± 0.6 mg/dl vs. 1.3 ± 0.5 mg/dl; p<0.0001). Follow-up serum creatinine levels however did not show significant alterations between the two groups (1.9 ± 0.4 mg/dl vs. 1.3 ± 0.5 mg/dl). No major complications were detected in the CCTA group. Signal-to-noise ratio (SNR) was comparable between i.v. CTA and CCTA (8.5 ± 4.6 vs. 7.7 ± 4.0; p = 0.37) and subjective image similarly revealed no differences with a good interobserver agreement (ICC = 0.647).

CONCLUSIONS

Catheter-directed CTA is safe and provides comparable image quality with a substantial retrenchment of the needed amount of iodine-based contrast medium. However, no benefit of the reduced contrast medium protocol with respect to renal function was observed.

Timeout for Contrast: Using Physician Behavior Modification to Reduce Contrast in the Catheterization Laboratory

BACKGROUND

As the number of procedures using contrast media continues to rise, the ensuing complications place an ever increasing burden on the healthcare system. Contrast-induced nephropathy (CIN) is a common postprocedural complication after cardiac catheterization.

OBJECTIVES

The purpose of our study was to evaluate the impact of physician behavioral modification on reducing the amount of contrast used during the procedure.

METHODS

All patients who underwent procedures in the cardiac catheterization laboratory from January 2013 to August 2016 were identified in addition to the total contrast used during the procedure, the type of procedure performed, and the operator performing the procedure. A new addition was made to the preprocedure checklist in September-October 2013 in the form of maximum allowed contrast for the patient.

RESULTS

A total of 12,118 cases were identified. Across all procedures, the mean contrast used during the 8 months prior to the intervention was 118 ml per procedure. Mean contrast used per procedure for the first year after the revised timeout was 105 ml, for the second year was 106 ml, and for the third year was 99 ml.

CONCLUSION

A significant reduction in radiocontrast use across all operators and procedures after the introduction of a revised timeout procedure that was seen, which is a change that was sustained over a period of three years. With this straightforward intervention involving physician behavioral modification, patients were exposed to less of the nephrotoxic contrast and were consequently at a lower risk of developing dose-depended CIN and other associated complications.

Impact of Chronic Kidney Disease on Decision Making and Management in Transcatheter Aortic Valve Interventions

The coexistence of chronic kidney disease (CKD) and severe aortic stenosis (AS) is common, and the prevalence of both is rising. The 2 conditions are inherently linked in that significant CKD may accelerate the development of AS and severe AS may result in deteriorating kidney function. The volume of and indications for transcatheter aortic valve implantation (TAVI) procedures are ever-increasing, and there are many challenges that need to be considered in patients with concomitant severe AS and CKD being assessed for TAVI. Throughout the process of working these patients up for definitive management of their valvular heart disease, the presence of CKD impacts on diagnostic investigations, treatment decisions, and therapeutic interventions. Herein we review the current literature regarding TAVI in patients with CKD focusing on the decision-making process and specific risks involved in TAVI and CKD. We also provide specific practical strategies to best manage this challenging patient cohort.

Serum and Tissue HIF-2 Alpha Expression in CIN, N-Acetyl Cysteine, and Sildenafil-Treated Rat Models: An Experimental Study

Background and Objectives: Contrast-induced nephropathy (CIN), is acute renal damage due to contrast agents. This study is conducted to evaluate serum and renal heterodimeric nuclear transcription factor (HIF)-2 alpha levels and its tissue expression in contrast-induced nephropathy, and in N-acetyl cysteine (NAC)-and Sildenafil-treated rat models. Materials/Methods: This randomized, controlled, interventional animal study was conducted on Wistar rats. Rats (n = 36) were randomly assigned to four groups: control (n = 9), CIN group (n = 9), CIN + NAC group (n = 9), and sildenafil (n = 9). The rat model was used to form iohexol-originated CIN. During the modeling, prophylactic treatment was performed at the 24th and 48th h. After 48 h of modeling, blood, urine, and tissue samples were obtained for biochemical analyses. HIF-2-α levels were measured in renal tissue, serum, and urine samples. Renal sections were also performed for histopathologic and immunohistochemical evaluations of renal injury and HIF-2-α expression. Results: In the CIN model, HIF-2α levels and other biochemical parameters were significantly increased (p < 0.01). Both sildenafil and NAC efficiently decreased renal damage due to contrast agents, as shown in histopathologic examinations (p < 0.05). Similarly, after treatment with sildenafil and NAC, HIF-2α levels were significantly decreased (p < 0.05). Conclusions: The current study shows that serum and tissue HIF-2α levels decrease in CIN. Besides, the levels and tissue expression of HIF-2α decrease with both NAC and sildenafil treatments. With further studies, HIF-2α can be investigated as a biomarker of CIN and can be used in the follow-up of patients with CIN.

A Bayesian network meta-analysis of preventive strategies for contrast-induced nephropathy after cardiac catheterization

BACKGROUND

The optimal preventive strategy for contrast induced acute kidney injury (CIAKI) in patients undergoing cardiac catheterization remains uncertain.

OBJECTIVE

We conducted Bayesian network meta-analysis (NMA) to compare different preventive strategies for CIAKI in these cohorts.

METHODS

Forty-nine randomized controlled trials were extracted using MEDLINE, EMBASE and CENTRAL data bases (inception-1st December 2017). We calculated median of the odds ratio (OR) with the corresponding 95% credible interval (CrI). The ranking probability of each treatment was based on SUCRA (surface under the cumulative ranking curve).

RESULTS

In NMA of 28,063 patients [normal saline (NS: 9716 patients), sodium bicarbonate (NaHCO3: 4484 patients), statin (2542 patients), N-acetylcysteine (NAC: 3006 patients), NAC + NaHCO3 (774 patients), NS + NAC (3807 patients), NS + NaHCO3 (135 patients) and placebo (3599 patients)], statins reduced the relative risk of CIAKI compared with NS (OR: 0.50; 95% CrI, 0.25-0.99), and placebo (OR: 0.44; 95% CrI, 0.24-0.83). Subgroup analyses showed that in patients receiving low osmolar contrast, statins reduced the relative risk of CIAKI by 58% versus NS, and 51% versus placebo. There were no significant differences across all the treatments in terms of risk of hemodialysis or all-cause mortality. Statins had the highest probability for reducing the risk of CIAKI (SUCRA, 0.86), risk of hemodialysis (SUCRA, 0.88) and all-cause mortality (SUCRA, 0.81).

CONCLUSION

Statins were the superior preventive strategy for reducing the risk of CIAKI compared with NS alone and placebo.

Outcomes after Angiography with Sodium Bicarbonate and Acetylcysteine

BACKGROUND

Intravenous sodium bicarbonate and oral acetylcysteine are widely used to prevent acute kidney injury and associated adverse outcomes after angiography without definitive evidence of their efficacy.

METHODS

Using a 2-by-2 factorial design, we randomly assigned 5177 patients at high risk for renal complications who were scheduled for angiography to receive intravenous 1.26% sodium bicarbonate or intravenous 0.9% sodium chloride and 5 days of oral acetylcysteine or oral placebo; of these patients, 4993 were included in the modified intention-to-treat analysis. The primary end point was a composite of death, the need for dialysis, or a persistent increase of at least 50% from baseline in the serum creatinine level at 90 days. Contrast-associated acute kidney injury was a secondary end point.

RESULTS

The sponsor stopped the trial after a prespecified interim analysis. There was no interaction between sodium bicarbonate and acetylcysteine with respect to the primary end point (P=0.33). The primary end point occurred in 110 of 2511 patients (4.4%) in the sodium bicarbonate group as compared with 116 of 2482 (4.7%) in the sodium chloride group (odds ratio, 0.93; 95% confidence interval [CI], 0.72 to 1.22; P=0.62) and in 114 of 2495 patients (4.6%) in the acetylcysteine group as compared with 112 of 2498 (4.5%) in the placebo group (odds ratio, 1.02; 95% CI, 0.78 to 1.33; P=0.88). There were no significant between-group differences in the rates of contrast-associated acute kidney injury.

CONCLUSIONS

Among patients at high risk for renal complications who were undergoing angiography, there was no benefit of intravenous sodium bicarbonate over intravenous sodium chloride or of oral acetylcysteine over placebo for the prevention of death, need for dialysis, or persistent decline in kidney function at 90 days or for the prevention of contrast-associated acute kidney injury. (Funded by the U.S. Department of Veterans Affairs Office of Research and Development and the National Health and Medical Research Council of Australia; PRESERVE ClinicalTrials.gov number, NCT01467466 .).

The Incidence, Risk Factors, and Outcomes of Contrast-Induced Nephropathy In Patients With Critical Limb Ischemia Following Lower Limb Angiography

Intra-arterial digital subtraction angiography (DSA) is commonly used for the diagnosis and treatment of patients with critical limb ischemia (CLI). The aim of this study was to analyze the incidence of contrast-induced nephropathy (CIN) in patients with CLI and to assess their outcomes. Between May 2013 and May 2014, a prospective and observational study was conducted with 107 patients admitted exclusively for CLI treatment. The main outcomes included hemodialysis independence (HI) and overall survival (OS), as assessed by Kaplan-Meier curves. Overall, there was a predominance of males (57%), with a mean age of 70.5 (10.7) years. The incidence of CIN was 35.5%, and chronic kidney failure was the only factor associated with elevated risk of this condition (relative risk [RR] = 1.9; 95% confidence interval = 1.17-3.09; P = .017). The median follow-up was 645 days, and in 720-day analyses, patients who experienced CIN had worse HI (81.2% vs 96.3%; P = .0107) and OS (49.5% vs 66.3%; P = .0463). The current study found a high incidence of CIN in patients with CLI after DSA. This renal impairment was associated with a worse prognosis in terms of survival.

Quercetin protects against radiocontrast medium toxicity in human renal proximal tubular cells

Radiocontrast media (RCM)-induced acute kidney injury (CI-AKI) is a major clinical problem whose pathophysiology is not well understood. Direct toxic effects on renal cells, possibly mediated by reactive oxygen species, have been postulated as contributing to CI-AKI. We investigated the effect of quercetin on human renal proximal tubular (HK-2) cells treated with the radiocontrast medium (RCM) sodium diatrizoate. Quercetin is the most widely studied flavonoid, and the most abundant flavonol present in foods. It has been suggested to have many health benefits, including angioprotective properties and anti-cancer effects. These beneficial effects have been attributed to its antioxidant properties and its ability to modulate cell signaling pathways. Incubation of HK-2 cells with 100 μM quercetin caused a decrease in cell viability and pre-treatment of HK-2 cells with 100 μM quercetin followed by incubation with 75 mgI/ml sodium diatrizoate for 2 hr caused a decrease in cell viability which was worse than in cells treated with diatrizoate alone. However, further incubation of the cells (for 22 hr) after removal of the diatrizoate and quercetin caused a recovery in cell viability in those cells previously treated with quercetin + diatrizoate and quercetin alone. Analysis of signaling molecules by Western blotting showed that in RCM-treated cells receiving initial pre-treatment with quercetin, followed by its removal, an increase in phosphorylation of Akt (Ser473), pSTAT3 (Tyr705), and FoxO3a (Thr32) as well as an induction of Pim-1 and decrease in PARP1 cleavage were observed. Quercetin may alleviate the longer-term toxic effects of RCM toxicity and its possible beneficial effects should be further investigated.

Safety of Radial Access for Primary Percutaneous Intervention in Patients With ST-Elevation Acute Myocardial Infarction: Results From a Low-Volume Center

Radial access for primary percutaneous coronary intervention (pPCI) in patients with ST-elevation acute myocardial infarction (STEMI) is recommended in high-volume experienced centers. This study investigated whether radial access for pPCI is safe even in a low-volume center. We performed radial access for pPCI in 171 patients. Major adverse cardiac events (total death, myocardial infarction, stroke) rate was 1.2%. The overall incidence of bleeding complications was 2.4%; there was no vascular complication at the access site. In patients with STEMI undergoing pPCI, the results of radial access in a low-volume center were acceptable. These findings support the safety of radial access in patients with STEMI.

Contrast-induced nephropathy: Basic concepts, pathophysiological implications and prevention strategies

Contrast-induced nephropathy (CIN) is reversible acute renal failure observed following administration of iodinated contrast media (CM) during angiographic or other medical procedures such as urography. There are various mechanisms through which CM develop their nephrotoxic effects, including oxidative stress and apoptosis. CIN is a real-life, albeit not very rare, entity. Exact pathophysiology remains obscure and no standard diagnostic criteria apply. The Acute Kidney Injury Network criteria was recently employed but its incidence/clinical significance warrants further clarification based on recent methodological advancements, because most published studies to date were contaminated by bias. The current study is a comprehensive review conducted to provide an overview of the basic concepts of CIN and summarize recent knowledge on its pathophysiology and the evidence supporting potential prevention strategies. CIN is expected to increase morbidity, hospital stay and mortality, while all patients scheduled to receive CM should undergo risk assessment for CIN and high-risk patients may be considered candidates for prevention strategies. The value of using compounds with antioxidant properties other than sodium bicarbonate, remains controversial, warranting further clinical investigation.

Prophylactic hydration to prevent contrast-induced nephropathy: much ado about nothing?

Clinical guidelines recommend prophylactic hydration to reduce the risk of contrast-induced nephropathy in high-risk patients, including those with chronic kidney disease. A recent single-center randomized trial showed no significant difference in the incidence of contrast-induced nephropathy in ambulatory patients with stage 3 chronic kidney disease who were randomized to no prophylactic hydration versus normal saline hydration. While these results may identify patients who are less likely to benefit from prophylactic hydration, nephrologists and interventionalists should carefully consider the generalizability of these results to individual patients.