Prevention of contrast-induced nephropathy through a knowledge of its pathogenesis and risk factors

Diuresis-matched versus standard hydration in patients undergoing percutaneous cardiovascular procedures: meta-analysis of randomized clinical trials

INTRODUCTION AND OBJECTIVES

Contrast-associated acute kidney injury (CA-AKI) is a potential complication of procedures requiring administration of iodinated contrast medium. RenalGuard, which provides real-time matching of intravenous hydration with furosemide-induced diuresis, is an alternative to standard periprocedural hydration strategies. The evidence on RenalGuard in patients undergoing percutaneous cardiovascular procedures is sparse. We used a Bayesian framework to perform a meta-analysis of RenalGuard as a CA-AKI preventive strategy.

METHODS

We searched Medline, Cochrane Library and Web of Science for randomized trials of RenalGuard vs standard periprocedural hydration strategies. The primary outcome was CA-AKI. Secondary outcomes were all-cause death, cardiogenic shock, acute pulmonary edema, and renal failure requiring renal replacement therapy. A Bayesian random-effect risk ratio (RR) with corresponding 95% credibility interval (95%CrI) was calculated for each outcome. PROSPERO database number CRD42022378489.

RESULTS

Six studies were included. RenalGuard was associated with a significant relative reduction in CA-AKI (median RR, 0.54; 95%CrI, 0.31-0.86) and acute pulmonary edema (median RR, 0.35; 95%CrI, 0.12-0.87). No significant differences were observed for the other secondary endpoints [all-cause death (RR, 0.49; 95%CrI, 0.13-1.08), cardiogenic shock (RR, 0.06; 95%CrI, 0.00-1.91), and renal replacement therapy (RR, 0.52; 95%CrI, 0.18-1.18)]. The Bayesian analysis also showed that RenalGuard had a high probability of ranking first for all the secondary outcomes. These results were consistent in multiple sensitivity analyses.

CONCLUSIONS

In patients undergoing percutaneous cardiovascular procedures, RenalGuard was associated with a reduced risk of CA-AKI and acute pulmonary edema compared with standard periprocedural hydration strategies.

Nephrotoxicity of iopamidol is associated with mitochondrial impairment in human cell and teleost models

Iopamidol is a nonionic, low-osmolar iodinated contrast agent used for angiography. Its clinical use is associated with renal dysfunction. Patients suffering from preexisting kidney disease have an increased risk of renal failure upon iopamidol administration. Studies in animals confirmed renal toxicity, but the involved mechanisms remain unclear. Therefore, the aim of the present study was to use human embryonic kidney cells (HEK293T) as a general cell model of mitochondrial damage, as well as, zebrafish larvae, and isolated proximal tubules of killifish to investigate factors promoting renal tubular toxicity of iopamidol with a focus on mitochondrial damage. Results from in vitro HEK293T cell-based assays indicate that iopamidol affects mitochondrial function Treatment with iopamidol induces ATP depletion, reduces the mitochondrial membrane potential, and elevates mitochondrial superoxide and reactive oxygen species accumulation. Similar results were obtained with gentamicin sulfate and cadmium chloride, two well-known model compounds associated with renal tubular toxicity. Confocal microscopy confirms changes in mitochondrial morphology, such as mitochondrial fission. Importantly, these results were confirmed in proximal renal tubular epithelial cells using ex vivo and in vivo teleost models. In conclusion, this study provides evidence for iopamidol-induced mitochondrial damage in proximal renal epithelial cells. Teleost models allow studying proximal tubular toxicity with translational relevance for humans.

Maslinic Acid: A New Compound for the Treatment of Multiple Organ Diseases

Maslinic acid (MA) is a pentacyclic triterpene acid, which exists in many plants, including olive, and is highly safe for human beings. In recent years, it has been reported that MA has anti-inflammatory, antioxidant, anti-tumor, hypoglycemic, neuroprotective and other biological activities. More and more experimental data has shown that MA has a good therapeutic effect on multiple organ diseases, indicating that it has great clinical application potential. In this paper, the extraction, purification, identification and analysis, biological activity, pharmacokinetics in vivo and molecular mechanism of MA in treating various organ diseases are reviewed. It is hoped to provide a new idea for MA to treat various organ diseases.

Exploring the effects of edaravone in rats with contrast-induced acute kidney injury

AIMS

Oxidative stress and inflammatory response play a vital role in the pathogenesis of contrast-induced acute kidney injury (CI-AKI). This study investigated the effects of edaravone in rats with CI-AKI.

MAIN METHODS

Male Sprague Dawley rats were randomly assigned into four groups (n = 11-14/group): control, edaravone (30 mg/kg/day intraperitoneally (IP)), CI-AKI, and edaravone with CI-AKI. The induction of CI-AKI was performed by dehydration and the administration of contrast media (iohexol) and inhibitors of prostaglandin (indomethacin) and nitric oxide synthesis (L-NAME: N-nitro L-arginine methyl ester). Edaravone was administered for two weeks before the induction of CI-AKI. Serum creatinine and urea, renal oxidative stress and inflammatory biomarkers, and histopathological alterations were evaluated after 48 h of contrast exposure.

KEY FINDINGS

Rats with CI-AKI showed a significant increase in serum creatinine and urea. The levels of antioxidant biomarkers including glutathione peroxidase, superoxide dismutase and reduced glutathione were significantly decreased in CI-AKI group versus control. Pre-treatment of rats with edaravone normalized kidney function and protected the kidney from oxidative damage as demonstrated by normalization of previous biomarkers. Furthermore, edaravone partially ameliorated renal histopathological alterations relative to the CI-AKI group, notably in the nephrons. No changes were observed in inflammatory biomarkers including tumour necrosis factor-alpha and interleukin-6 among all groups.

SIGNIFICANCE

The current findings suggest that edaravone could be a potential strategy to ameliorate developing CI-AKI possibly by improving renal antioxidant capacity. Further studies are warranted to expand the current understanding of the use of edaravone in the various models of AKI.

Compatibility and stability of non-ionic iodinated contrast media in peritoneal dialysis solution and safe practice considerations for CT peritoneography

BACKGROUND

Computerised tomographic (CT) peritoneography is performed on peritoneal dialysis (PD) patients to identify peritoneal boundary defects, dialysate maldistributions and loculated fluid collections. Iodinated contrast media are added to dialysate and infused through the dialysis catheter, and CT images are obtained. Chemical compatibility of contrast media with dialysis solutions has not been studied. In some institutions, pharmacists charged with oversight of compounded sterile preparations have placed a moratorium on the use of contrast media-dialysate mixtures until compatibility data become available. This study was undertaken to examine the compatibility of non-ionic iodinated contrast agents added to PD solution for the performance of CT peritoneography.

METHODS

100 mL of three non-ionic iodinated contrast agents, iopamidol 370 mgI/mL, iohexol 300 mgI/mL and iodixanol 320 mgI/mL, were mixed with 2 L 1.5% dextrose PD solution and stored at 2-8°C, 25°C and 40°C. Observations at predefined intervals were made over 5 days for visual appearance, turbidity, pH, drug concentration and chemical degradation.

RESULTS

Iopamidol, iohexol and iodixanol were stable for 5 days under study conditions. The contrast-dialysate mixture remained clear and colourless, no turbidity changes observed, pH and drug concentrations were stable and no increase in existing impurities or new impurities were detected.

CONCLUSIONS

The addition of commonly used non-ionic iodinated contrast agents to 1.5% dextrose dialysis solution is chemically stable, meeting the criteria set forth in the standards and guidelines of the US Pharmacopeia and the Institute of Safe Medication Practices. A protocol for performing CT peritoneography is recommended herein to facilitate patient safety and diagnostic reliability of the imaging study.

Maslinic Acid Attenuates Ischemia/Reperfusion-Induced Acute Kidney Injury by Suppressing Inflammation and Apoptosis Through Inhibiting NF-κB and MAPK Signaling Pathway

Inflammation and apoptosis are the major contributors to the mechanisms of acute kidney injury (AKI) due to renal ischemia-reperfusion injury (IRI). Maslinic acid (MA), a pentacyclic triterpene acid mostly found in dietary plants, the current study was to demonstrate the renoprotective effect of MA on IRI-induced AKI, and to investigate the role of inflammation and apoptosis-related signaling pathways as a molecular mechanism. C57BL/6J mice were subjected to IRI for 72 h, and MA was daily administered by intraperitoneal injection during this period. In parallel, rat renal proximal tubule cells (NRK52E) were prophylactically treated with MA and then exposed to hydrogen peroxide (H₂O₂). MA treatment significantly inhibited the mRNA expression of interleukin (IL-1β), tumor necrosis factor-α (TGF-α), monocyte chemoattractant protein-1 (MCP-1), and intercellular adhesion molecule-1(ICAM-1). Also, MA reduced the expression of Bax/Bcl2 ratio and cleaved caspase-3. In NRK52 cells, MA inhibited the IκBα degradation, blocked NF-κB/p65 phosphorylation, and nuclear translocation. The phosphorylation of ERK, JNK, and p38 was attenuated by MA in IRI-induced kidney injury and H₂O₂-stimulated NRK52 cells. The expression levels of IL-1β, MCP-1, and ICAM-1 were upregulated in H₂O₂-stimulated NRK52E cells, which was attenuated by NF-κB inhibitor. H₂O₂ treatment increased the Bax/Bcl2 ratio and cleaved caspase-3 in NRK52E cells, which was counteracted by MAPK inhibitors. Together, our data demonstrate that MA suppresses IR-induced AKI injury through NF-κB and MAPK signaling pathways and that MA is a promising agent in the treatment of kidney diseases.

Preparation and Characterization of Nanosuspensions of Triiodoaniline Derivative New Contrast Agent, and Investigation into Its Cytotoxicity and Contrast Properties

Iodine-based contrast agents have limitations such as rapid clearance, potential renal toxicity, non-specific blood pool distribution, headache, and adverse events. Nowadays, it is quite common to work with nanosized systems in order to eliminate the side effects of contrast agents. This study aims to synthesize a new iodinated contrast agent, prepare its nanosuspension by using the nanoprecipitation method, investigate its cytotoxicity, and compare its contrast properties with iohexol and iopromide through in-vitro experiments. The values of nanosuspension particle size and zeta potential have been found to be ~ 400 nm and ~ (-) 15 mV, respectively. In-vitro cellular viability findings indicated that the nanosuspension has lower cytotoxicity than the iohexol and iopromide. In the computed tomography (CT) imaging study of contrast features of nanosuspensions and two commercial agents, which involved 86 CT examinations using 31 parameters and two different devices, it was found that iodine had a stronger presence in its nanosuspension form than in iohexol and iopromide, which were the other two commercial contrast agents, when used in equal amounts. Thus in the case of nanosuspensions contrast brightness was achieved by using less iodine, while the same brightness could be obtained with higher doses of iohexol and iopromide. CT imaging therefore be done without much chemical use, which indicates that it may witness fewer side effects in the future.

Resveratrol and lycopene ameliorate contrast-induced nephropathy in a rabbit model

Oxidative stress appears to possess a central role in CIN pathophysiology. Resveratrol (Res) and lycopene (Lyc) are strong natural antioxidants evaluated in a limited number of CIN animal studies in vivo. The aim of the study was to evaluate the potential renoprotective effects of Res/Lyc in a CIN rabbit model. Twenty-four adult male New Zealand white rabbits were equally assigned into four groups: control (saline), CIN (intravenous iopromide; 7.5 g iodine/kg), Res + CIN (per os Res; 5 mg/kg), and Lyc + CIN (per os Lyc; 4 mg/kg). Serum Cr (sCr); symmetric/asymmetric dimethylarginine (SDMA/ADMA); oxidative stress biomarkers: malondialdehyde; total antioxidant capacity; catalase; glutathione) were evaluated in blood samples at three time points: right after (0 h); 24 h; 48 h after iopromide/saline administration. CD20⁺/CD3⁺ lymphocytes were determined (48 h). All animals were sacrificed at 48 h and both kidneys collected. Oxidative stress biomarkers were measured in renal tissue. sCr and SDMA/ADMA levels increased significantly in CIN compared to all groups. Oxidative stress secondary to CIN in blood/kidneys was suppressed by Res/Lyc. B and T lymphocytes decreased significantly in CIN compared to all groups. The present study provides emerging evidence that Res/Lyc ameliorate CIN by modulating oxidant/antioxidant balance in blood/renal tissue and by inhibiting vasoconstriction/blood cytotoxicity.

Safety and Efficacy of Hybrid Angiography in Chronic Lower Extremity Ischemia Patients at Risk of Contrast-Induced Acute Kidney Injury

AIM

The aim of the study was to assess the feasibility and safety of hybrid angiography consisting of carbon dioxide (CO₂) angiography supplemented by small doses of iodinated contrast medium (ICM) in the endovascular treatment of chronic limb threatening ischemia (CLTI) patients with pre-existing chronic kidney disease (CKD).

PATIENTS AND METHODS

This prospective study comprised all non-dialysis-dependent CKD patients presenting for endovascular management of CLTI. All endovascular interventions were done using CO₂ as a contrast medium whether alone or supplemented by ICM (hybrid angiography) to treat unilateral arterial steno-occlusive lesions of iliac, femoropopliteal, or BTK arteries. Study outcomes included feasibility of the device, technical success, and freedom from contrast-induced acute kidney injury (CI-AKI), renal replacement therapy, and CO₂ angiography-related complications.

RESULTS

A total of 206 CKD patients underwent endovascular intervention using CO₂ only as a contrast medium (159 patients, 77.2%), or hybrid CO₂-ICM angiography (47 patients, 22.8%). The overall technical success was 95.6%. Patients were followed up for a mean period of 17.9 ± 4.6 months. The mean volumes of CO₂, and ICM consumption were 200.7 ± 95.1 mL, and 11.8 ± 4.4 mL, respectively. The mean procedural, and fluoroscopy times were 95.6 ± 12.5 and 49.5 ± 10.8 minutes, respectively. BTK lesions were significantly associated with the need for hybrid angiography (P = <.0001). The mean pre- and postoperative serum creatinine levels were comparable (P = .08). Two patients (4.3%) showed transient manifestations of CI-AKI, but neither required renal replacement therapy. No statistically significant differences were encountered between the two study groups regarding procedure outcomes.

CONCLUSION

Hybrid CO₂-ICM angiography is safe, feasible, effective, and a fairly simple alternative during endovascular interventions to treat chronic lower extremity ischemia. Using supplemental small volumes of ICM to overcome the suboptimal images generated by CO₂ alone does not jeopardize the renal functions in CKD patients.

The Impact of Chronic Kidney Disease on Peripheral Artery Disease and Peripheral Revascularization

Chronic kidney disease (CKD) is a clinical condition characterized by high morbidity and mortality. Globally, CKD is also increasing in prevalence and incidence. The two principal kidney measures namely estimated glomerular filtration rate (eGFR) and albuminuria have been found to be predictors of renal and cardiovascular (CV) endpoints including peripheral artery disease (PAD). The prevalence of PAD was increased in CKD patients and, particularly, in patients with more severe CKD stages. Despite the fact that revascularization strategies are suitable in CKD patients in similar fashion to non-CKD patients, few CKD patients underwent these procedures. In fact, if it is true that revascularization improves prognosis in PAD patients irrespective of baseline eGFR, it was also demonstrated that CKD patients, who underwent revascularization, were at higher risk for amputations, mortality, re-intervention and perioperative complications. With the present review article, we have examined the association between CKD, PAD and peripheral revascularization highlighting data about epidemiology, pathophysiologic mechanisms, and results from previous observational and intervention studies. We have also examined the future perspectives and challenges of research around the association between CKD and PAD.

Therapeutic effects of hysterosalpingography contrast media in infertile women: what do we know about the H2O in the H2Oil trial and why does it matter?

Recent interest in the use of oil-soluble contrast media (OSCM) for hysterosalpingography (HSG) and other tubal flushing procedures is largely the result of publication of the large, multicentre, randomized controlled H2Oil trial in the New England Journal of Medicine in 2017, addressing the long-held suspicion that pregnancy rates following HSG with OSCM are higher than if a water-soluble contrast media (WSCM) is used. However, the findings of this trial have been compromised by the WSCM selected for comparison with OSCM. The chosen WSCM belongs to a superceded class of ionic media, with an iodine concentration, osmolality and viscosity all lying at the extreme end of the range for water-soluble radiographic contrast. The requirement for safe, cheap, versatile WSCM for intravascular use during computerized tomography, angiography and interventional procedures has resulted in considerable refinement of WSCM, with current widespread use of non-ionic, low osmolality or iso-osmolar WSCM in radiology, including for HSG. However, the use of the earlier ionic, high osmolality agents such as that selected for the H2Oil trial persists for HSG in some centres, despite potential adverse effects on the endometrium and fallopian tubal epithelium compared with more modern, less toxic WSCM. Knowledge of the variety of physical and chemical characteristics of the available WSCM is essential for interpretation of the current literature and establishing the most effective and safe water-soluble agent to use for HSG. Design of future clinical trials to establish the potential superiority of OSCM over WSCM for fertility enhancement must include the use of the readily available, inexpensive modern WSCM. While the fertility rates following OSCM HSG have been shown to be high in women with idiopathic infertility, more robust trials are required before the widespread use of OSCM for HSG or other modalities such as ultrasound and laparoscopy should be adopted.

Definition of acute kidney injury impacts prevalence and prognosis in ACS patients undergoing coronary angiography

Background

Development of acute kidney injury (AKI) in invasively managed patients with acute coronary syndrome (ACS) is associated with a markedly increased mortality risk. Different definitions of AKI are in use, leading to varying prevalence and outcome measurements. The aim of the present study is to analyze an ACS population undergoing coronary angiography for differences in AKI prevalence and outcome using four established AKI definitions.

Methods

944 patients (30% female) were enrolled in a prospective registry between 2003 and 2005 with 6-month all-cause mortality as outcome measure. Four established AKI definitions were used: an increase in serum creatinine (sCR) ≥ 1.5 fold, ≥ 0.3 mg/dl, and ≥ 0.5 mg/dl and a decrease in eGFR > 25% from baseline (AKIN 1, AKIN 2, CIN, and RIFLE definition groups, respectively).

Results

AKI rates varied widely between the different groups. Using the CIN definition, AKI frequency was lowest (4.4%), whereas it was highest if the RIFLE definition was applied (13.2%). AKIN 2 displayed a twofold higher AKI prevalence compared with AKIN 1 (10.2% vs. 5.3% (p < 0.001)). AKI was a strong risk factor for mid-term mortality, with distinctive variability between the definitions. The lowest mortality risk was found in the RIFLE group (HR 6.0; 95% CI 3.7–10.0; p < 0.001), whereas CIN revealed the highest risk (HR 16.7; 95% CI 9.9–28.1; p < 0.001).

Conclusion

Prevalence and outcome in ACS patients varied considerably depending on the AKI definition applied. To define patients with highest renal function-associated mortality risk, use of the CIN definition seems to have the highest prognostic relevance.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12872-021-01985-9.

Darbepoetin alfa reduces cell death due to radiocontrast media in human renal proximal tubular cells

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Radiocontrast medium, sodium diatrizoate, reduces renal cell viability in vitro.

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Effect of darbepoetin on diatrizoate-treated cells was studied.

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Pre-treatment of renal cells with darbepoetin could reduce diatrizoate toxicity.

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Darbepoetin caused changes in the activation state of signaling molecules.

The hypersialylated erythropoiesis stimulating agent (ESA) darbepoetin alfa was developed for the treatment of anemia, and has also been reported to have other nonerythropoietic effects. This study outlines one such effect against the toxicity of the radiocontrast medium (RCM) sodium diatrizoate (NaD) in human renal proximal tubular (HK-2) cells in vitro. Using a standard cell viability assay, we observed that pre-incubation of HK-2 cells with darbepoetin (at concentrations of 0.25and 1.0 μg/mL) for 2.5 h prior to addition of NaD (75 mg I/mL, for 2 h) reduced the decrease in cell viability due to the RCM, assayed 22 h after removal of the NaD, whilst maintaining the cells incubated with darbepoetin. Western blot analysis showed that darbepoetin reduced the phosphorylation of c-Jun N-terminal kinases (JNK)1/2 over a period of 1 h incubation with NaD, but did not have an obvious effect on several other targets associated with cell death/survival. However, incubation of HK-2 cells with darbepoetin for a further 22 h after prior exposure to NaD (75 mg I/mL, for 2 h) and subsequent immunoblotting showed that darbepoetin: caused recovery of the activity (phosphorylation) of pro-proliferative/survival signalling molecules, such as Akt (Ser473), STAT (signal transducer and activator of transcription)3(Tyr705); decreased activation of the pro-apoptotic transcription factor FOXO3a by increasing its phosphorylation at Thr32; decreased phosphorylation (activation) of p38 Mitogen activated protein kinase; and reduced poly(ADP-ribose)polymerase (PARP)-1 cleavage. In summary, we present here a beneficial nonerythropoietic effect of darbepoetin alfa against radiocontrast-induced toxicity together with modulation of signalling molecules that play a crucial role in determining cell fate.

Heat Shock Protein 27 Is an Emerging Predictor of Contrast-Induced Acute Kidney Injury on Patients Subjected to Percutaneous Coronary Interventions

Contrast-induced acute kidney injury (CI-AKI) is a serious complication associated with considerable morbidity and mortality. Heat-shock protein 27 (HSP27) plays a role in the defense of the kidney tissue against various forms of cellular stress, including hypoxia and oxydative stress, both features associated with CI-AKI. The aim of our study was to evaluate a potential predictive value of HSP27 for CI-AKI in patients subjected to percutaneous coronary interventions (PCI). Included were 343 selected patients subjected to PCI. Exclusion criteria were conditions that potentially might influence HSP27 levels. HSP27 serum levels were evaluated prior to PCI, together with serum creatinine, the concentration of which was also evaluated twice at 48 and 72 h post PCI. CI-AKI was diagnosed in 9.3% of patients. Patients in whom CI-AKI was diagnosed were older (p < 0.001), were more often females (p = 0.021), had higher prevalence of diabetes (p = 0.011), hypotension during PCI (p < 0.001), albuminuria (p = 0.004) as well as multivessel disease (p = 0.002), received higher contrast volume (p = 0.006), more often received contrast volume (CV) above the maximum allowed contrast dose (MACD) (p < 0.001), and had lower HSP27 level (p < 0.001). On multivariate analysis, CV > MACD (OR 1.23, p = 0.001), number of diseased vessels (OR 1.27, p = 0.006), and HSP27 (OR 0.81, p = 0.001) remained independent predictors of CI-AKI. Low concentration of HSP27 is an emerging, strong and independent predictor of CI-AKI in patients subjected to PCI.

Evaluation of coenzyme Q10 combined with or without N-acetyl cysteine or atorvastatin for preventing contrast-induced kidney injury in diabetic rats

Combined antioxidants effect for prevention of contrast-induced nephropathy (CIN) remains unclear. This study assessed the potential protective effects of coenzyme Q10 (CoQ10) alone or combined with N-acetyl cysteine (NAC) or atorvastatin against CIN in diabetic rats. Animals were randomly divided into five groups, including control and four disease groups with CIN and diabetes. Group 2 included diabetic rats with CIN. Groups 3-5 included diabetic rats that received CoQ10, CoQ10 and NAC, or CoQ10 and atorvastatin, respectively, before CIN induction. Serum, urine, and tissue were collected to evaluate renal protective effects of tested agents. Renal biomarkers, oxidative stress, and histopathological alterations were investigated. Rats with CIN showed significant renal impairment as revealed by the deleterious effects on kidney function and histology. While induction of CIN did not affect the renal levels of catalase, glutathione peroxidase (GPx), and thiobarbituric acid reactive substances, pretreatment of animals with CoQ10/NAC showed significant increase in GPx and catalase levels versus controls. Lastly, pretreatment with CoQ10/atorvastatin showed regenerative effect on distal tubules with mild kidney histology alterations relative to CIN rats. The combined use of CoQ10/atorvastatin could be a potential strategy to prevent CIN. However, future studies are warranted to test different combinations for longer prophylactic periods.

Identification of the candidate lncRNA biomarkers for acute kidney injury: a systematic review and meta-analysis

Background: This meta-analysis aims to summarize the studies of lncRNAs dysregulation in individual acute kidney injury (AKI) and identify the potential lncRNA biomarkers of AKI.Research design and methods: We systematically searched four databases to identify the lncRNA expression studies of AKI in animal models and patients. The lncRNAs expression data were extracted from 38 included studies, and lncRNA vote-counting strategy was applied to identify significant lncRNA biomarkers. The predicted targets of lncRNA biomarkers were obtained by searching Co-LncRNA, RBPmap, and LncBase v.2. Further, GO enrichment analysis and KEGG pathway analysis were performed.Results: We recognized a significant lncRNA signature of 21 up-regulated and 11 down-regulated lncRNAs, among which TapSAKI, XIST, MALAT1, CASC2, and HOXA-AS2 were dysregulated both in AKI rodent models and patients. About 28.0% of these lncRNAs mainly exist in the nucleus, which was also the most enriched GO cellular components term. The most relevant GO terms in biological process and molecular function associated with these lncRNAs were splicing, processing, and binding of mRNA.Conclusions: The present meta-analysis identified 31 significant dysregulated lncRNAs from 38 studies. TapSAKI, XIST, MALAT1, CASC2, and HOXA-AS2 were considered as the potential predictive biomarkers and therapeutic targets of AKI.

Cerebral angiography: Techniques and practice

As a refresher course on current techniques and practice of cerebral angiography, this chapter outlines the steps in effective angiography, incorporating modern quality and safety considerations. The format is step-by-step from preprocedure to intraprocedure to postprocedure for ease of reference. The chapter will serve as a framework for the fledgling angiographer, augmenting the important teaching provided by a seasoned angiographer.

Predictive value of combining the level of fibrinogen and antithrombin III for contrast-induced nephropathy in coronary artery disease patients undergoing percutaneous coronary intervention

Contrast-induced nephropathy (CIN) is a common adverse event in the diagnosis and treatment of coronary intervention. The current study investigated the predictive effect of preoperative fibrinogen (FIB) combined with antithrombin III (AT-III) on CIN following percutaneous coronary intervention (PCI). A total of 394 patients who underwent PCI between October 2018 and May 2019 were selected for the present study. Pre-procedural FIB levels and AT-III activity were measured before PCI. CIN was defined as a 0.5 mg/dl or 25% increase in serum creatinine levels 48 to 72 h after exposure to a radiocontrast agent. Patients were classified into CIN and non-CIN groups. CIN occurred in 48 (12.2%) patients. The serum FIB levels were significantly higher in patients who developed CIN compared with those who did not develop CIN. In addition, AT-III levels ≤89.5% were associated with higher rates of CIN. Logistical regression analysis showed that high FIB, and low AT-III and albumin levels were high-risk factors associated with CIN. For FIB, the area under the receiver operating characteristic curve (AUC) for predicting CIN was 0.653. The optimal cut-off value was 3.48 g/l with a sensitivity of 45.8% and a specificity of 79.7% [95% confidence interval (CI): 0.603-0.701; P=0.0002)]. For AT-III, the AUC was 0.711, and the optimal cut-off value was 89.5%, with a sensitivity of 81.3% and specificity of 58.2% (95% CI: 0.659-0.758; P<0.0001). When combining FIB and AT-III, the AUC was 0.747. The optimal cut-off value was 0.090424, with a diagnostic sensitivity of 93.8% and specificity of 46.6% (95% CI: 0.697-0.792; P<0.0001). The results showed that FIB combined with AT-III resulted in improved predictive accuracy of CIN (FIB vs. AT-III, AUC=0.653 vs. 0.711, P=0.292; FIB vs. FIB + AT-III, AUC=0.653 vs. 0.747, P=0.012; AT-III vs. FIB + AT-III, AUC=0.711 vs. 0.747, P=0.138). Pre-procedural levels of FIB, AT-III and albumin were independently associated with an increased risk of CIN. Furthermore, the results suggested that the combination of FIB and AT-III was a better predictor of CIN after PCI.

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.

Updated guidelines for intravenous contrast use for CT and MRI

Intravenous (IV) contrast material is used extensively for CT and MRI scans done in emergency departments (ED). Its use is essential to make many critical diagnoses in ED patients. While adverse reactions can occur, newer research has added to our knowledge of IV contrast media tolerance and safety leading to improved and more liberal guidelines for intravenous contrast use. The updated information described in this review article indicates how intravenous contrast can be used safely in more patients, more expeditiously and with fewer precautions than with prior guidelines. This review article explains the basis for the new recommendations for intravenous contrast material use and describes indicated precautions and preparations to avoid adverse reactions for iodinated agents used for CT and gadolinium agents for MRI.

Contrast-Induced Acute Kidney Injury: Review and Practical Update

Contrast-induced acute kidney injury (CI-AKI) is an important consideration in patients undergoing cardiac catheterization. There has been a continuous strive to decrease morbidity and improve procedural safety. This review will address the pathophysiology, predictors, and clinical management of CI-AKI with a concise overview of the pathophysiology and a suggested association with left atrial appendage closure. Minimizing contrast administration and intravenous fluid hydration are the cornerstones of an effective preventive strategy. A few adjunctive pharmacotherapies hold promise, but there are no consensus recommendations on prophylactic therapies.

Investigating the Possible Protective Role of Direct Intra-arterial Administration of Mannitol and N-Acetylcysteine and Per Os Administration of Simvastatin Against Contrast-Induced Nephropathy: An Experimental Study in a Rabbit Model

PURPOSE

Contrast-induced nephropathy (CIN) is one of the leading causes of hospital-acquired acute kidney injury due to the use of iodinated contrast media in various interventional procedures like endovascular aneurysm repair. Its pathophysiology remains mostly unclear. The purpose of the present study was to comparatively study the possible protective role of direct intra-arterial administration of mannitol and acetylcysteine and per os administration of simvastatin in a histopathological level.

MATERIALS AND METHODS

In the present study, we administered iopromide directly in the infrarenal aorta of 24 New Zealand white rabbits after laparotomy. Animals were divided in four groups of six: G1 received iopromide with no protection, G2 iopromide with mannitol, G3 iopromide with acetylcysteine, and G4 iopromide with simvastatin. Renal function blood parameters were assessed prior to the administration, and in 48 h; histopathological evaluation of the kidneys was performed.

RESULTS

CIN was evident only in the no protection group G1. Moreover, G1 demonstrated significantly more severe lesions than groups G2, G3, and G4 regarding histopathological findings in glomeruli, vacuolization of tubular epithelial cells, tubular proteinaceous casts, and tubular necrosis. According to our results, intra-arterial administration of mannitol seems to be effective in protection against tubular necrosis.

CONCLUSION

In general, all three agents demonstrated a protective role in preventing the development of CIN, although it seems that there are various pathways that remain to be investigated further.

Contrast media (meglumine diatrizoate) aggravates renal inflammation, oxidative DNA damage and apoptosis in diabetic rats which is restored by sulforaphane through Nrf2/HO-1 reactivation

Diabetes mellitus is an independent risk factor for renal impairment in patients exposed to contrast media. It doubles the risk and decreases survival rate of contrast induced nephropathy (CIN). Sulforaphane has antioxidant properties via Nrf2 activation. The interaction of diabetes and/or sulforaphane with contrast media on Nrf2 regulation is not yet understood. Herein, diabetes was induced by a single intra-peritoneal injection of streptozotocin. Animals were then divided into five groups; control non-diabetic group; diabetic group; diabetic/sulforaphane group; diabetic/CIN group; diabetic/CIN/sulforaphane group. Animals were assessed 24 h after CIN induction. Sulforaphane improved the impaired nephrotoxicity parameters, histopathological features, and oxidative stress markers induced by contrast media (meglumine diatrizoate) in diabetic rats. Immunofluorescence detection revealed increased Nrf2 expression in kidney sections after sulforaphane pretreatment. Moreover, gene expression of Nrf2 and HO-1 were up-regulated, while IL-6 and caspase3 were down-regulated in kidney tissues of animals pretreated with sulforaphane. In NRK-52E cells, sulforaphane pretreatment significantly ameliorated the cytotoxicity of meglumine diatrizoate. However, silencing Nrf2 using small interfering RNA (siRNA) abolished the cytoprotective effects of sulforaphane. Collectively, the results of this study suggest that Nrf2/HO-1 pathway has a protective role against CIN and support the clinical implication of Nrf2 activators, such as sulforaphane, in CIN particularly in diabetic patients.

Alpha-tocopherol and contrast-induced nephropathy: A meta-analysis of randomized controlled trials

Background: Contrast-induced nephropathy (CIN) is a relevant cause of acute renal dysfunction and is associated with an increased morbidity and mortality. Purpose: Verify the effect of α-tocopherol pre-treatment on CIN prevention in subjects with chronic kidney disease. Methods: A Medline/Embase and clinicaltrials.gov were searched up to May 1st, 2017. Randomized controlled trials recruiting patients undergoing diagnostic or therapeutic radiocontrast infusion comparing the effect of either oral or i.v. multiple administration of pharmacological dose of α-tocopherol in preventing CIN versus placebo were included. A random-effects model, calculating Mantel-Haenszel odds ratio with 95% confidence interval, was applied to study the effect of α-tocopherol on CIN occurrence. Funnel plot analysis was used to assess publication bias, while agreement within studies was measured by the I² index and tested with the Q-Cochran test. Results: Out of 242 studies, 4 trials were selected. CIN incidence resulted significantly lower in α-tocopherol compared to placebo group (5.8% vs. 15.4%, MH-OR [95% C.I.] 0.34 [0.19 - 0.59]). Alpha-tocopherol treatment was associated with both a tendential higher eGFR (mean difference 2.19 [95% C.I. -0.41; 4.79] mL/min) and lower creatinine level (mean difference -0.06 [95% C.I. -0.21; 0.09] mg/dl) compared to placebo. No relevant publication bias (p = 0.48) and heterogeneity (I² = 0%; χ² = 1.01, df = 3 [p = 0.80], I² = 0%) were evident. Conclusions: Alpha-tocopherol pre-treatment is associated with reduction of incidence of CIN. Its administration deserves to be further explored as a simple and inexpensive tool for CIN prevention.

Personalized administration of contrast medium with high delivery rate in low tube voltage coronary computed tomography angiography

Background

High delivery rate is an important factor in optimizing contrast medium administration in coronary computed tomography angiography (CCTA). A personalized contrast volume calculation algorithm incorporating high iodine delivery rate (IDR) can reduce total iodine dose (TID) and produce optimal vessel contrast enhancement (VCE) in low tube voltage CCTA. In this study, we developed and validated an algorithm for calculating the volume of contrast medium delivered at a high rate for patients undergoing retrospectively ECG-gated CCTA with low tube voltage protocol.

Methods

The algorithm for an IDR of 2.22 gI·s^-1 was developed based on the relationship between VCE and contrast volume in 141 patients; test bolus parameters and characteristics in 75 patients; and, tube voltage in a phantom study. The algorithm was retrospectively tested in 45 patients who underwent retrospectively ECG-gated CCTA with a 100 kVp protocol. Image quality, TID and radiation dose exposure were compared with those produced using the 120 kVp and routine contrast protocols.

Results

Age, sex, body surface area (BSA) and peak contrast enhancement (PCE) were significant predictors for VCE (P<0.05). A strong linear correlation was observed between VCE and contrast volume (r=0.97, P<0.05). The 100-to-120 kVp contrast enhancement conversion factor (E_c) was calculated at 0.81. Optimal VCE (250 to 450 HU) and diagnostic image quality were obtained with significant reductions in TID (32.1%) and radiation dose (38.5%) when using 100 kVp and personalized contrast volume calculation algorithm compared with 120 kVp and routine contrast protocols (P<0.05).

Conclusions

The proposed algorithm could significantly reduce TID and radiation exposure while maintaining optimal VCE and image quality in CCTA with 100 kVp protocol.

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

Effect of Alprostadil on the Prevention of Contrast-Induced Nephropathy: A Meta-Analysis of 36 Randomized Controlled Trials

Contrast-induced nephropathy (CIN) is the third leading cause of acquired acute renal injury in hospitalized patients. Alprostadil plays a role in the maintenance and redistribution of intrarenal blood flow and the excretion of electrolytes and water. However, the effectiveness of alprostadil in preventing CIN remains controversial. Thirty-six articles with a total of 5495 patients were included in this study. Both groups (experimental group and control group) received standard hydration therapy. In the experimental group, patients received different doses of alprostadil. Serum creatinine (SCr), blood urea nitrogen (BUN), estimated glomerular filtration rate (eGFR), cystatin C, creatinine clearance rate (CCr), and β2-microglobulin (β2-MG) were measured at 24, 48, and 72 hours after contrast media injection. The incidence of CIN in the experimental group was significantly lower than that in the control group (6.56% vs 16.74%). The level of SCr, cystatin C, BUN, and β2-MG in the experimental group was lower than those in the control group; CCr and eGFR in the experimental group were higher than those in the control group. This study demonstrated that alprostadil may reduce the incidence of CIN in patients undergoing coronary angiogram and/or percutaneous coronary intervention.

Is the risk of contrast-induced nephropathy a real contraindication to perform intravenous contrast enhanced Computed Tomography for non-traumatic acute abdomen in Emergency Surgery Department?

BACKGROUND

Contrast enhanced Computed Tomography (CCT) is the most used imaging test to investigate acute abdominal clinical conditions, because of its high sensitivity and specificity. It is mandatory to make a correct and prompt diagnosis when life threatening abdominal diseases as mesenteric ischemia are suspected. Contrast medium administration was linked to acute renal failure, therefore radiologist often prefer to perform CCT without contrast in patients needing to undergo the exam with increased serum creatinine.  The aim of the review was to focus on the incidence of contrast induced nephropathy in patients presenting non-traumatic acute abdominal clinical conditions, who underwent CCT with intravenous contrast agent administration in emergency setting.

MATERIALS AND METHODS

The systematic review protocol was guided by the Preferred Reporting Items for Systematic Reviews and Meta-analyses Protocol (PRISMA-P). Quality of the evidence will be evaluated using the Grading of Recommendations Assessment, Development and Evaluation (GRADE) methodology.

RESULTS

The strongest currently available evidence on the incidence of post-contrast acute kidney injury (AKI) following intravenous contrast agent administration consists in a meta-analysis of observational studies. Data extracted from meta-analyses demonstrate that, compared with non-contrast CT, CCT was not significantly associated with AKI. Moreover, the risk of AKI (RR=0.79; 95% confidence interval [CI]: 0.62, 1.02; P=.07), death (RR=0.95; 95% CI: 0.55, 1.67; P=.87), and dialysis (RR=0.88; 95% CI: 0.23, 3.43; P=.85) is similar, compared with the risk of AKI in the non-contrast medium group. Furthermore, intravenous low-osmolality iodinated contrast material is a nephrotoxic risk factor, but not in patients with a stable SCr level less than 1.5 mg/dL, therefore many factors other than contrast material could affect PC-AKI rates.

DISCUSSION AND CONCLUSIONS

The benefits of diagnostic information gained from contrast enhanced TC in assessing AA are fundamental in some clinical scenarios. The risk of contrast induced nephropathy (CIN) is negligible in patients with normal renal function but the incidence appears to rise to as high as 25% in patients with pre-existing renal impairment or in the presence of risk factors such as diabetes, advanced age, vascular disease and use of certain concurrent medications. The incidence of CIN/AKI after intravenous contrast administration is very low in general population. Radiologists and referring physicians should be familiar with the risk factors for renal disease, CIN and preventing measures.

CT Angiography in the Lower Extremity Peripheral Artery Disease Feasibility of an Ultra-Low Volume Contrast Media Protocol

Purpose

The ALARA principle is not only relevant for effective dose (ED) reduction, but also applicable for contrast media (CM) management. Therefore, the aim was to evaluate the feasibility of an ultra-low CM protocol in the assessment of peripheral artery disease (PAD).

Materials and methods

Fifty PAD patients were scanned on third-generation dual-source computed tomography, from diaphragm to the forefoot, as follows: tube voltage: 70 kV, reference effective tube current: 90 mAs, collimation: 192 × 2 × 0.6 mm, with individualized acquisition timing. The protocol ED (mSv) was quantified with dedicated software. CM protocol consisted of 15 ml test bolus and 30 ml main bolus (300 mgI/ml) injected at 5 ml/s, followed by a 40 ml saline chaser at the same flow rate. Aorto-popliteal bolus transit time was used to calculate the overall acquisition time and delay. Objective (hounsfield units—HU; contrast-to-noise ratio—CNR) and subjective image quality (four-point Likert score) were assessed at different anatomical regions from the aorta down to the forefoot.

Results

Mean attenuation values were exceeding 250 HU from aorta down to the anterior tibial artery with CNR < 13. However, decline in attenuation was observed in more distal region with mean values of 165 and 199 HU, in left and right dorsalis pedis artery, respectively. Mode subjective image quality from the level of aorta down to the popliteal segment was excellent; below the knee mode score was good. The mean ED per protocol was 1.1 ± 0.5 mSv.

Conclusion

Use of an ultra-low CM volume protocol at 70 kV is feasible in the evaluation of PAD, resulting in good to excellent image quality with mean ED of 1.1 ± 0.5 mSv.

Level of evidence

Level 3, Local non-random sample

Comparison of Normal Saline, Ringer's Lactate, and Sodium Bicarbonate for Prevention of Contrast-induced Nephropathy in Patients with Coronary Angiography: A Randomized Double-blind Clinical Trial

Contrast-induced nephropathy (CIN) is one the most important renal complications following contrast injection in percutaneous coronary intervention. We compared the protective effect of normal saline (NLS), Ringer's lactate (RL), and sodium bicarbonate (Bi). In this study, patients with coronary angiography indication were divided into three groups by simple randomization method: NLS, RL, and Bi solution groups. Creatinine (Cr) alterations, glomerular filtration rate, and urine pH were evaluated prior and after the procedure. Data were analyzed with SPSS and P value less than 0.05 was taken as significant. In this study, 300 patients [150 men (50%), mean age 59.1 ± 10.6 years] were studied. The CIN incidence overall was 10% (30 patients): 8.3% (8 patients) in NLS; 16.5% (17 patients) in RL; and 5% (5 patients) in Bi group. It was significantly different among three groups (P = 0.018), and CIN incidence was significantly lower in Bi vs. RL group (P = 0.012). Baseline Cr clearance was higher in patients who developed CIN (78.4 ± 26.0 vs. 69.8 ± 21.6 mL/dL, P = 0.044). Urine pH after trial in CIN group was lower than the patients without CIN (5.5 ± 1.4 vs. 6.3 ± 1.8 mL/dL, P = 0.024). Higher urine pH and its change during study were seen in Bi group (P < 0.05). Cr at the initiation of study and the use of RL vs. Bi may be prognostic factors in CIN progression (P < 0.002). Sodium barcarbonate as fluid had more protective effect than NSL or RL on prevention of CIN in patients undergoing coronary angiography. The risk factors for CIN in our study were higher baseline serum Cr and use of RL as hydration fluid.

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.

Effect of trimetazidine on preventing contrast-induced nephropathy in diabetic patients with renal insufficiency

BACKGROUND

Our study sought to assess the effect of trimetazidine (TMZ) on preventing contrast-induced nephropathy (CIN) in diabetic patients with renal insufficiency.

MATERIALS AND METHODS

106 diabetic patients with renal insufficiency who were undergoing coronary angiography (CAG) and/or percutaneous coronary intervention (PCI) were enrolled in this study. Standard hydration was administered to both groups (the TMZ group and the control group). In the TMZ group, patients were orally administered TMZ for 48 hours before and 24 hours after CAG and/or PCI. Serum creatinine (Scr), cystatin C and the glomerular filtration rate (eGFR) were measured before as well as 24 hours, 48 hours and 72 hours after contrast media injection. The incidence of CIN and major cardiovascular events (MACE) was also evaluated in both groups.

RESULTS

Scr, cystatin C and the eGRF in the TMZ group were better than those in the control group after 24 hours (OR: 0.78, 95% CI: 0.54-0.82; OR: 0.66, 95% CI: 0.62-0.73; OR: 1.2, 95% CI: 1.02-1.53, respectively), 48 hours (OR: 0.69, 95% CI: 0.52-0.73; OR: 0.76, 95% CI: 0.69-0.84; OR: 1.5, 95% CI: 1.25-1.68, respectively) and 72 hours (OR: 0.82, 95% CI: 0.77-0.91; OR: 0.85, 95% CI: 0.71-0.92; OR: 1.67, 95% CI: 1.33-1.72, respectively). The incidence of CIN (9.26% vs 16.67%) and MACE (7.41% vs 18.51%) in the TMZ group was significantly lower than that in the control group (P < 0.05).

CONCLUSIONS

Our study suggests that TMZ could reduce the incidence of CIN and MACE in diabetic patients with renal insufficiency who are undergoing CAG and/or PCI.

Association of post-procedural early (within 24h) increases in serum creatinine with all-cause mortality after coronary angiography

BACKGROUND

The majority of patients undergoing coronary angiography (CAG) or percutaneous coronary intervention (PCI) are discharged early, with only early (within 24h) serum creatinine (SCr) data available without evidence of clinical prognosis. We aimed to systemically evaluate the association between post-procedural early increase in SCr and all-cause mortality following CAG.

METHODS

We performed a retrospective sub-study analysis within a prospective observational study including 3091 consecutive patients with baseline and post-procedural early (within 24h) SCr data. The degree (mild, moderate, or large) of absolute and relative increases in SCr from baseline. The mean follow-up time was 2.49years.

RESULT

Moderate or large early increases in SCr were relatively rare (large increase: >1.0mg/dl [0.5%], >100% [0.4%]), whereas mild absolute and relative increases in SCr were more common (mild increase: 0.25 to 0.50mg/dl [4.5%], 25% to 50% [5.9%]). During the follow-up period, there were 136 post-procedural deaths (5.6%). After adjustment for confounders, mild absolute and relative increases in SCr were associated with increased mortality (hazard ratio [HR]: 1.9 and 1.8, respectively, both P<0.05). Moderate or large increases in SCr were associated with higher mortality, even higher than with pre-existing renal dysfunction (HR: 5.36 and 4.12 for moderate increase [0.5 to 1.0mg/dl] and estimated glomerular filtration rate<60ml/min).

CONCLUSION

Post-procedural mild, moderate, or large early increase in SCr, is associated with significantly increased long-term mortality. Although moderate or large increase in SCr following CAG was relatively rare, the prognosis is more serious, and is worse than that of pre-existing renal dysfunction.

CLINICAL TRIAL REGISTRATION

Predictive Value of Contrast Volume to Creatinine Clearance Ratio (PRECOMIN, ClinicalTrials.govNCT01400295).

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.

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.

Efficacy of alprostadil for preventing of contrast-induced nephropathy: A meta-analysis

Contrast-induced nephropathy (CIN) has become the third-leading cause of hospital-acquired acute renal injury. Although alprostadil has been proposed as an effective preventative measure, this conclusion remains inconsistent. Thus, we performed a meta-analysis of the published studies on this topic to evaluate the preventative effect of alprostadil on CIN. Databases, including PubMed, the Web of Science, Cochrane Library, Wanfang, the China Biological Medicine Database (SinoMed) and the China National Knowledge Infrastructure (CNKI) were systematically searched. Nineteen clinical trials involving 2267 individuals were identified. We utilized a random or a fixed effect model to calculate the pooled odd ratios (ORs) and the standardized mean differences (SMD), respectively. Compared to the control group, the CIN risk decreased significantly in the alprostadil group (P < 0.00001, OR = 0.29, 95% CI = 0.21-0.39). In the subgroup of coronary angiography patients, the use of alprostadil also decreased the risk of CIN (P < 0.00001, OR = 0.27, 95% CI: 0.19-0.39). In conclusion, Alprostadil might be associated with a significant reduction in postcontrast Scr, BUN and CysC level and decrease the incidence of CIN.

The ischemic/nephrotoxic acute kidney injury and the use of renal biomarkers in clinical practice

The term Acute Renal Failure (ARF) has been replaced by the term Acute Kidney Injury (AKI). AKI indicates an abrupt (within 24-48h) decrease in Glomerular Filtraton Rate, due to renal damage, that causes fluid and metabolic waste retention and alteration of electrolyte and acid-base balance. The renal biomarkers of AKI are substances or processes that are indicators of normal or impaired function of the kidney. The most used renal biomarker is still serum creatinine that is inadequate for several reasons, one of which is its inability to differentiate between hemodynamic changes of renal function ("prerenal azotemia") from intrinsic renal failure or obstructive nephropathy. Cystatin C is no better in this respect. After the description of the pathophysiology of "prerenal azotemia" and of Acute Kidney Injury (AKI) due to ischemia or nephrotoxicity, the renal biomarkers are listed and described: urinary NAG, urinary and serum KIM-1, serum and urinary NGAL, urinary IL-18, urinary L-FABP, serum Midkine, urinary IGFBP7 and TIMP2, urinary α-GST and π-GST, urinary ɣGT and AP, urinary β₂M, urinary RBP, serum and urinary miRNA. All have been shown to appear much earlier than the rise of serum Creatinine. Some of them have been demonstrated to predict the clinical outcomes of AKI, such as the need for initiation of dialysis and mortality.

Delineating the Role of Various Factors in Renal Disposition of Digoxin through Application of Physiologically Based Kidney Model to Renal Impairment Populations

Development of submodels of organs within physiologically-based pharmacokinetic (PBPK) principles and beyond simple perfusion limitations may be challenging because of underdeveloped in vitro-in vivo extrapolation approaches or lack of suitable clinical data for model refinement. However, advantage of such models in predicting clinical observations in divergent patient groups is now commonly acknowledged. Mechanistic understanding of altered renal secretion in renal impairment is one area that may benefit from such models, despite knowledge gaps in renal pathophysiology. In the current study, a PBPK kidney model was developed for digoxin, accounting for the roles of organic anion transporting peptide 4C1 (OATP4C1) and P-glycoprotein (P-gp) in its tubular secretion, with the aim to investigate the impact of age and renal impairment (moderate to severe) on renal drug disposition. Initial PBPK simulations based on changes in glomerular filtration rate (GFR) underestimated the observed reduction in digoxin renal excretion clearance (CL_R) in subjects with moderately impaired renal function relative to healthy. Reduction in either proximal tubule cell number or the OATP4C1 abundance in the mechanistic kidney model successfully predicted 59% decrease in digoxin CL_R, in particular when these changes were proportional to reduction in GFR. In contrast, predicted proximal tubule concentration of digoxin was only sensitive to changes in the transporter expression/ million proximal tubule cells. Based on the mechanistic modeling, reduced proximal tubule cellularity and OATP4C1 abundance, and inhibition of OATP4C1-mediated transport, are proposed as possible causes of reduced digoxin renal secretion in renally impaired patients.