Cytotoxic effects of ionic high-osmolar, nonionic monomeric, and nonionic iso-osmolar dimeric iodinated contrast media on renal tubular cells in vitro

Predictive Value of the Naples Prognostic Score for Acute Kidney Injury in ST-Elevation Myocardial Infarction Patients Undergoing Primary Percutaneous Coronary Intervention

The purpose of this investigation was to investigate whether there was an association between the Naples prognostic score and the development of acute kidney injury (AKI) in ST-elevation myocardial infarction (STEMI) patients following primary percutaneous coronary intervention (pPCI). The study comprised 2901 consecutive STEMI patients who had pPCI. For each patient, the Naples prognostic score was determined. To evaluate the predictive performance of the Naples score (which included either continuous and categorical variables), we developed a Nested model and a nested model combined with the Naples score. The Naples prognostic score was the most significant predictor of AKI occurrence after admission creatinine, age, and contrast volume. The continuous Naples prognostic score model provided the best prediction performance and discriminative ability. The C-index of the Nested and full models with continuous Naples prognostic score were significantly higher than that of the Nested model. The decision curve analysis found that the overall model had a higher full range of probability of clinical net benefit than the baseline model, with a 10% AKI likelihood. The present study found that the Naples prognostic score may be useful to predict the risk of AKI in STEMI patients undergoing pPCI.

Surface-modified bacteria: synthesis, functionalization and biomedical applications

The past decade has witnessed a great leap forward in bacteria-based living agents, including imageable probes, diagnostic reagents, and therapeutics, by virtue of their unique characteristics, such as genetic manipulation, rapid proliferation, colonization capability, and disease site targeting specificity. However, successful translation of bacterial bioagents to clinical applications remains challenging, due largely to their inherent susceptibility to environmental insults, unavoidable toxic side effects, and limited accumulation at the sites of interest. Cell surface components, which play critical roles in shaping bacterial behaviors, provide an opportunity to chemically modify bacteria and introduce different exogenous functions that are naturally unachievable. With the help of surface modification, a wide range of functionalized bacteria have been prepared over the past years and exhibit great potential in various biomedical applications. In this article, we mainly review the synthesis, functionalization, and biomedical applications of surface-modified bacteria. We first introduce the approaches of chemical modification based on the bacterial surface structure and then highlight several advanced functions achieved by modifying specific components on the surface. We also summarize the advantages as well as limitations of surface chemically modified bacteria in the applications of bioimaging, diagnosis, and therapy and further discuss the current challenges and possible solutions in the future. This work will inspire innovative design thinking for the development of chemical strategies for preparing next-generation biomedical bacterial agents.

Evaluating the Effectiveness of Pretreatment With Intravenous Fluid in Reducing the Risk of Developing Contrast-Induced Nephropathy: A Systematic Review and Meta-Analysis

Contrast media administration to patients during cardiac events increases the risk of developing contrast-induced nephropathy (CIN). CIN is among some complications usually associated with the percutaneous coronary intervention and may result in acute renal failure. Several risk factors are associated with CIN. These risk factors include; age (elderly patients), pre-existing renal impairment, diabetes mellitus, and the use of high osmolar contrast media. Studies have shown that several measures such as using low osmolar contrast media, N-acetylcysteine, intravenous sodium bicarbonate, and hydration through oral or intravenous fluid administration play a significant role in CIN incidence reduction. Hydration using intravenous fluid, especially saline solution, has been critical in preventing CIN. Prehydration using the intravenous fluid before contrast media administration is vital.

A systematic literature search with meta-analysis for relevant and original articles was carried out from 2000 to 2022 on databases such as PubMed, Cochrane Library, Google Scholar, ScienceDirect, Web of Science, and Embase. The search on the databases was based on various keywords related to intravenous fluid and CIN. The studies that met the inclusion criteria were critically analyzed, and data such as study design, interventions, participants, and outcomes of the research were retrieved.

Out of the 784 results yielded during the initial search, ten articles met the eligibility criteria and were included in the study. The data analysis obtained from the included studies showed that pretreatment using intravenous fluid has conflicting results. Some studies showed that hydrating patients using intravenous fluid before contrast media administration significantly reduces the risk of CIN. In contrast, others claimed that intravenous fluid has minimal impact on preventing CIN.

Despite the different investigations conducted on CIN, it remains insufficiently understood. From the analysis, most of the studies support that intravenous fluid administration decreases the occurrence of CIN in patients that receive contrast media. The analysis also has established that oral hydration is similar to intravenous fluid administration in reducing CIN incidence.

A Novel Prediction Model of Acute Kidney Injury Based on Combined Blood Variables in STEMI

BACKGROUND

Development of acute kidney injury (AKI) is associated with poor prognosis in patients with ST-segment elevation myocardial infarction (STEMI).

OBJECTIVE

This study sought to investigate whether a combination of pre-procedural blood tests could predict the incidence of AKI in patients with STEMI.

METHODS

A total of 908 consecutive Japanese patients with STEMI who underwent primary percutaneous coronary intervention within 48 hours of symptom onset were recruited and divided into derivation (n = 617) and validation (n = 291) cohorts. A risk score model was created based on a combination of parameters assessed on routine blood tests on admission.

RESULTS

In the derivation cohort, multivariate analysis showed that the following 4 variables were significantly associated with AKI: blood sugar ≥200 mg/dL (odds ratio [OR]: 2.07), high-sensitivity troponin I >1.6 ng/mL (upper limit of normal ×50) (OR: 2.43), albumin ≤3.5 mg/dL (OR: 2.85), and estimated glomerular filtration rate <45 mL/min/1.73 m² (OR: 2.64). Zero to 4 points were given according to the number of those factors. Incremental risk scores were significantly associated with a higher incidence of AKI in both cohorts (P < 0.001). Receiver-operating characteristic curve analysis of risk models showed adequate discrimination between patients with and without AKI (derivation cohort, area under the curve: 0.754; 95% confidence interval: 0.733-0.846; validation cohort, area under the curve: 0.754; 95% confidence interval: 0.644-0.839).

CONCLUSIONS

Our novel laboratory-based model might be useful for early prediction of the post-procedural risk of AKI in patients with STEMI.

Developing a system for in vivo imaging of maize roots containing iodinated contrast media in soil using synchrotron XCT and XRF

AIMS

We sought to develop a novel experimental system which enabled application of iodinated contrast media to in vivo plant roots intact in soil and was compatible with time-resolved synchrotron X-ray computed tomography imaging. The system was developed to overcome issues of low contrast to noise within X-ray computed tomography images of plant roots and soil environments, the latter of which can complicate image processing and result in the loss of anatomical information.

METHODS

To demonstrate the efficacy of the system we employ the novel use of both synchrotron X-ray computed tomography and synchrotron X-ray fluorescence mapping to capture the translocation of the contrast media through root vasculature into the leaves.

RESULTS

With the application of contrast media we identify fluid flow in root vasculature and visualise anatomical features, which are otherwise often only observable in ex vivo microscopy, including: the xylem, metaxylem, pith, fibres in aerenchyma and leaf venation. We are also able to observe interactions between aerenchyma cross sectional area and solute transport in the root vasculature with depth.

CONCLUSIONS

Our novel system was capable of successfully delivering sufficient contrast media into root and leaf tissues such that anatomical features could be visualised and internal fluid transport observed. We propose that our system could be used in future to study internal plant transport mechanisms and parameterise models for fluid flow in plants.

SUPPLEMENTARY INFORMATION

The online version contains supplementary material available at 10.1007/s11104-020-04784-x.

Cumulative iodinated contrast exposure for computed tomography during acute kidney injury and major adverse kidney events

OBJECTIVES

To determine if contrast-enhanced CT imaging performed in patients during their episode of AKI contributes to major adverse kidney events (MAKE).

METHODS

A propensity score-matched analysis of 1127 patients with AKI defined by KDIGO criteria was done. Their mean age was 63 ± 16 years with 56% males. A total of 419 cases exposed to CT contrast peri-AKI were matched with 798 non-exposed controls for 14 covariates including comorbidities, acute illnesses, and initial AKI severity; outcomes including MAKE and renal recovery in hospital were compared using bivariate analysis and logistic regression. MAKE was a composite of mortality, renal replacement therapy, and doubling of serum creatinine on discharge over baseline; renal recovery was classified as early versus late based on a 7-day timeline from AKI onset to nadir creatinine or cessation of renal replacement therapy in survivors.

RESULTS

Sixty-two patients received cumulatively > 100 mL of CT contrast, 143 patients had > 50-100 mL, and 214 patients had 50 mL or less; MAKE occurred in 34%, 17%, and 21%, respectively, as compared with 20% in non-exposed controls (p = 0.008 for patients with > 100 mL contrast versus none). More contrast-exposed patients experienced late renal recovery (27% versus 20%) and longer hospital days (median 10 versus 8) than non-exposed patients (all p < 0.01). On multivariate analysis, cumulative CT contrast > 100 mL was independently associated with MAKE (odds ratio 2.39 versus non-contrast, adjusted for all confounders, p = 0.005); cumulative CT contrast under 100 mL was not associated with MAKE.

CONCLUSIONS

High cumulative volume of CT contrast administered to patients with AKI is associated with worse short-term renal outcomes and delayed renal recovery.

KEY POINTS

• Cumulative intravenous iodinated contrast for CT imaging of more than 100 mL, during an episode of acute kidney injury, was independently associated with worse renal outcomes and less renal recovery. • These adverse outcomes including renal replacement therapy were not more frequent in similar patients who received cumulatively 100 mL or less of CT contrast, compared with non-exposed patients. • More patients with CT contrast exposure during acute kidney injury experienced delayed renal recovery.

Iodinated Contrast Agents Reduce the Efficacy of Intravenous Recombinant Tissue-Type Plasminogen Activator in Acute Ischemic Stroke Patients: a Multicenter Cohort Study

This study aimed to investigate whether the application of iodinated contrast agents before intravenous (IV) recombinant tissue plasminogen activator (rt-PA) reduces the efficacy in acute ischemic stroke (AIS) patients. To determine whether the application of iodinated contrast agents before intravenous rt-PA reduces the efficacy in AIS patients. We analyzed our prospectively collected data of consecutive AIS patients receiving IV rt-PA treatment in the MISSION CHINA study. Clinical outcome at 3 months was assessed with modified Rankin Scale (mRS) score and dichotomized into good outcome (0-2) and poor outcome (3-6). Symptomatic intracerebral hemorrhage (sICH) was defined as cerebral hemorrhagic transformation in combination with clinical deterioration of National Institutes of Health Stroke Scale (NIHSS) score ≥ 4 points at 24-h. We performed logistic regression analysis and propensity score matching analysis to investigate the impact of iodinated contrast agents before IV rt-PA on poor outcome and sICH, respectively. A total of 3593 patients were finally included, and iodinated contrast agents were used before IV rt-PA among 859 (23.9%) patients. Patients in the iodinated contrast group were more likely to result in poor outcome (39.9% vs 33.4%, P = 0.001) and sICH (3.4% vs 1.5%, P < 0.001), compared with non-contrast group. Binary logistic regression analysis revealed that the application of iodinated contrast agents was independently associated with poor outcome (OR 1.342; 95% CI 1.103-1.631; P = 0.003) and sICH (OR 1.929; 95% CI 1.153-3.230; P = 0.012), respectively. After propensity score matching, the application of iodinated contrast agents was still independently associated with poor outcome (OR 1.246; 95% CI 1.016-1.531; P = 0.034) and sICH (OR 1.965; 95% CI 1.118-3.456; P = 0.019). Applying iodinated contrast agents before IV rt-PA may reduce the thrombolytic efficacy in AIS patients. Further benefit-risk analysis might be needed when iodinated contrast-used imaging is considered before intravenous thrombolysis.

Bismuth chelate as a contrast agent for X-ray computed tomography

Backgrounds

Due to the unexpected side effects of the iodinated contrast agents, novel contrast agents for X-ray computed tomography (CT) imaging are urgently needed. Nanoparticles made by heavy metal elements are often employed, such as gold and bismuth. These nanoparticles have the advantages of long in vivo circulation time and tumor targeted ability. However, due to the long residence time in vivo, these nanoparticles may bring unexpected toxicity and, the preparation methods of these nanoparticles are complicated and time—consuming.

Methods

In this investigation, a small molecular bismuth chelate using diethylenetriaminepentaacetic acid (DPTA) as the chelating agent was proposed to be an ideal CT contrast agent.

Results

The preparation method is easy and cost—effective. Moreover, the bismuth agent show better CT imaging for kidney than iohexol in the aspect of improved CT values. Up to 500 µM, the bismuth agent show negligible toxicity to L02 cells and negligible hemolysis. And, the bismuth agent did not induce detectable morphology changes to the main organs of the mice after intravenously repeated administration at a high dose of 250 mg/kg. The pharmacokinetics of the bismuth agent follows the first—order elimination kinetics and, it has a short half—life time of 0.602 h. The rapid clearance from the body promised its excellent biocompatibility.

Conclusions

This bismuth agent may serve as a potential candidate for developing novel contrast agent for CT imaging in clinical applications.

Virtual monoenergetic images preserve diagnostic assessability in contrast media reduced abdominal spectral detector CT

OBJECTIVES

To investigate if low-keV virtual monoenergetic images (VMI_40keV) from abdominal spectral detector CT (SDCT) with reduced intravenous contrast media application (RCM) provide abdominal assessment similar to conventional images with standard contrast media (SCM) dose.

METHODS

78 patients with abdominal SDCT were retrospectively included: 41 patients at risk for adverse reactions who received 44 RCM examinations with 50 ml and 37 patients who underwent 44 SCM examinations with 100 ml of contrast media (CM) and who were matched for effective body diameters. RCM, SCM images and RCM-VMI_40keV were reconstructed. Attenuation and signal-to-noise ratio (SNR) of liver, pancreas, kidneys, lymph nodes, psoas muscle, aorta and portal vein were assessed ROIs-based. Contrast-to-noise ratios (CNR) of lymph nodes vs aorta/portal vein were calculated. Two readers evaluated organ/vessel contrast, lymph node delineation, image noise and overall assessability using 4-point Likert scales.

RESULTS

RCM were inferior to SCM images in all quantitative/qualitative criteria. RCM-VMI_40keV and SCM images showed similar lymph node and muscle attenuation (p = 0.83,0.17), while for all other ROIs, RCM-VMI_40keV showed higher attenuation (p ≤ 0.05). SNR was comparable between RCM-VMI_40keV and SCM images (p range: 0.23-0.99). CNR of lymph nodes was highest in RCM-VMI_40keV (p ≤ 0.05). RCM-VMI_40keV received equivalent or higher scores than SCM in all criteria except for organ contrast, overall assessability and image noise, where SCM were superior (p ≤ 0.05). However, RCM-VMI_40keV received proper or excellent scores in 88.6/94.2/95.4% of the referring cases.

CONCLUSIONS

VMI_40keV counteract contrast deterioration in CM reduced abdominal SDCT, facilitating diagnostic assessment.

ADVANCES IN KNOWLEDGE

SDCT-derived VMI_40keV provide adequate depiction of vessels, organs and lymph nodes even at notable CM reduction.

Pathophysiology of Contrast-Induced Acute Kidney Injury (CIAKI)

Contrast-induced acute kidney injury (CIAKI) is a severe complication associated with the use of iodinated contrast media (CM); a sudden but potentially reversible fall in glomerular filtration rate (GFR) typically occurring 48-72 hours after CM administration. Principal risk factors related with the presentation of CIAKI are preexisting chronic kidney disease and diabetes mellitus. Studies on CIAKI present considerable complexity because of differences in CM type and dose, controversies in definition and baseline comorbidities. Despite that, it should be noted that CIAKI poses a serious health problem because it is a very common cause of hospitalacquired AKI, linked to increased morbidity and mortality and utilizing growing healthcare resources. The pathogenesis of CIAKI is heterogeneous and, thus, is incompletely understood. Three basic mechanisms appear to simultaneously occur for CIAKI development: Renal vasoconstriction and medullary hypoxia, tubular cell toxicity and reactive oxygen species formation. The relative contribution of each one of these mechanisms is unknown but they ultimately lead to epithelial and endothelial cell apoptosis and GFR reduction. Further research is needed in order to better clarify CIAKI pathophysiology and accordingly introduce effective preventive and therapeutic strategies.

The immunohistochemical and histologic effects of contrast medium on uterus, fallopian tubes and ovaries, given during hysterosalpingography: rat study

Objective:

Previous studies have shown that damage occurs to internal genital tract during hysterosalpingography (HSG). The aim was to show that endometrial and tubal epithelium underwent free radical damage during HSG in an animal model.

Material and Methods:

Forty rats were evaluated in five different groups. Two groups received ionizing radiation (15-20 miliRad three times) only. Two further groups received ionizing radiation in combination with iohexol (1-2 mL). The remaining group served as control. Groups were evaluated after seven and forty-two days. Inflammation and cellular changes were evaluated histopathologically. Cellular activity of antioxidant enzymes was assessed immunohistochemically.

Results:

Inflammation, and cellular changes were detected at certain rates in all groups (p<0.001). Glutathione reductase, catalase, superoxide dismutase, glutathione S-transferase activities were found to be increased after the HSG (p<0.001).

Conclusion:

It is obvious that the cell suffers acute and chronic damage during HSG due to both radioactivity and chemicals. Although there is a lot of research done before, there is no definitive method yet to protect against the harmful effects of iodinated contrast agents and ionizing radiation. So, new methods need to be explored to protect cells and tissues from reactive oxygen radical damage caused by HSG.

Metformin treatment for patients with diabetes and chronic kidney disease: A Korean Diabetes Association and Korean Society of Nephrology consensus statement

The safety of metformin use for patients with type 2 diabetes mellitus (T2DM) and advanced kidney disease is controversial, and more recent guidelines have suggested that metformin be used cautiously in this group until more definitive evidence concerning its safety is available. The Korean Diabetes Association and the Korean Society of Nephrology have agreed on consensus statements concerning metformin use for patients with T2DM and renal dysfunction, particularly when these patients undergo imaging studies using iodinated contrast media (ICM). Metformin can be used safely when the estimated glomerular filtration rate (eGFR) is ≥ 45 mL/min/1.73 m². If the eGFR is between 30 and 44 mL/min/1.73 m², metformin treatment should not be started. If metformin is already in use, a daily dose of ≤ 1,000 mg is recommended. Metformin is contraindicated when the eGFR is < 30 mL/min/1.73 m². Renal function should be evaluated prior to any ICM-related procedures. During procedures involving intravenous administration of ICM, metformin should be discontinued starting the day of the procedures and up to 48 hours post-procedures if the eGFR is < 60 mL/min/1.73 m².

The optimal monoenergetic spectral image level of coronary computed tomography (CT) angiography on a dual-layer spectral detector CT with half-dose contrast media

Background

To investigate the optimal monoenergetic level of spectral reconstructions in coronary computed tomography angiography (coronary CTA) on a dual-layer spectral detector computed tomography (SDCT) with half-dose contrast media.

Methods

Two hundred patients with suspected coronary artery disease (CAD) were enrolled in this prospective coronary CTA study and randomly divided into a routine-dose contrast media group and a half-dose contrast media group (each n=100). Coronary CTA was performed using SDCT with prospective electrocardiogram (ECG)-gated mode. A tube voltage of 120 kVp was used, along with an automated tube current modulation. A dose of iodixanol 270 mgI/mL of 0.8 and 0.4 mL/kg was administered to the routine and half-dose groups, respectively. For the routine-dose group, 120 kVp polychromatic images with a model-based iterative reconstruction (IMR) (Group A) were reconstructed. For the half-dose group, three monoenergetic levels of images were reconstructed (Group B, 45 keV; Group C, 50 keV; and Group D, 55 keV). Objective indicators [mean CT values; noise; signal-to-noise ratio (SNR); and contrast-to-noise ratio (CNR)] and subjective indicators (contrast, sharpness, subjective noise, and acceptability) in each group were compared.

Results

There were no significant differences in demographics or radiation dose (1.83±0.51 vs. 1.80±0.53 mSv, P=0.78) between the routine- and half-dose groups. The average iodine loads were 15.33±2.26 and 7.48±1.14 g, respectively. Mean CT values, SNR, CNR, and subjective contrast in Group C were higher than those in Group A (P<0.05), and there were no significant differences in other indicators between Group C and Group A (P>0.05). The objective and subjective noise in Group B were worse than those in Group A (P<0.05). The contrast, sharpness, and acceptability of Group D were all worse than those of Group A (P<0.05).

Conclusions

Compared to routine polychromatic images, 50 keV monoenergetic images can provide equivalent or improved coronary image quality in coronary CTA performed on SDCT with half the amount of contrast media.

The Relationship Between Contrast Associated Nephropathy and Coronary Collateral Circulation in very Old Patients

Background: The aim of this study was to investigate whether there is a relationship between coronary collateral circulation (CCC) and contrast associated nephropathy (CAN) in very elderly patients. Methods: Patients aged 90 years or older with at least one major occlusion of the coronary artery proximal or mid-section were included in the study. CCC was graded according to the Rentrop classification. CAN was defined as an increase in blood creatinine value of 25% or more on the second day after coronary angiography. Results: Thirty-six patients who met the study criteria were included in the study. In the study group, CAN developed in 12 patients (CAN (+) group), 24 patients did not develop CAN (CAN (−) group). The creatinine levels before coronary angiography were 1.05 ± 0.12 in the CAN (−) group and 1.22 ± 0.14 in the CAN (+) group. Baseline creatinine values were significantly higher in the CAN (+) group (p = 0.001). The contrast agent used in the CAN (+) group was significantly higher (p = 0.001). In the CAN (+) group, nine patients (43%) had poor collateral circulation, whereas only three patients (20%) had well-developed collateral circulation. In a logistic regression analysis, the collateral class was not a risk factor for CAN, whereas contrast agent volume and basal creatinine were independent predictors of CAN. Conclusion: We found that CCC grade was not associated with the development of CAN in very old patients, but the amount of contrast agent and pre-procedure creatinine values were independent variables in the development of CAN.

Carbon dioxide-angiography for patients with peripheral arterial disease at risk of contrast-induced nephropathy

Patients with peripheral arterial disease (PAD) and critical limb ischemia are at risk for limb amputation and require urgent management to restore blood flow. Patients with PAD often have several comorbidities, including chronic kidney disease, diabetes mellitus, and hypertension. Diagnostic and interventional angiography using iodinated contrast agents provides excellent image resolution but can be associated with contrast-induced nephropathy (CIN). The use of carbon dioxide (CO₂) as a contrast agent reduces the volume of iodine contrast required for angiography and reduces the incidence of CIN. However, CO₂ angiography has been underutilized due to concerns regarding safety and image quality. Modern CO₂ delivery systems with advanced digital subtraction angiography techniques and hybrid angiography have improved imaging accuracy and reduced the incidence of CIN. Awareness of the need for optimal imaging conditions, contraindications, and potential complications have improved the safety of CO₂ angiography. This review aims to highlight current technological advances in the delivery of CO₂ in vascular angiography for patients with PAD and critical limb ischemia, which result in limb preservation while preventing kidney damage.

Subclinical Contrast-Induced Acute Kidney Injury in Patients Undergoing Cerebral Computed Tomography

INTRODUCTION

The nephrotoxicity of modern contrast media remains controversial. Novel biomarkers of kidney damage may help in identifying a subclinical structural renal injury not revealed by widely used markers of kidney function.

OBJECTIVE

The aim of this study was to investigate clinical (contrast-induced acute kidney injury [CI-AKI]) and subclinical CI-AKI (SCI-AKI) after intra-arterial administration of Iodixanol and Iopamidol in patients with an estimated glomerular filtration rate (eGFR) ≥60 mL/min/1.73 m2.

METHODS

This is a prospective observational monocentric study. Urinary sample was collected at 4-8 h after contrast medium exposure to measure neutrophil gelatinase associated lipocalin (NGAL) and the product tissue inhibitor of metalloproteinase-2 and insulin-like growth factor-binding protein 7 ([TIMP-2] × [IGFBP7]), while blood samples were collected at 24 and 48 h after exposure to measure serum creatinine.

RESULTS

One hundred patients were enrolled, of whom 53 were exposed to Iodixanol and 47 to Iopamidol. Patients in Iodixanol and Iopamidol groups were comparable in terms of demographics, pre-procedural and procedural data. No patient developed CI-AKI according KDIGO criteria, while 13 patients reported SCI-AKI after exposure to iodine-based medium contrast (3 patients in Iodixanol group and 10 patients in Iopamidol group), defined by positive results of NGAL and/or [TIMP-2] × [IGFBP7]. A positive correlation was found between NGAL and [TIMP-2] × [IGFBP7] in the analysed population (Spearman's rho 0.49, p < 0.001). In logistic regression analysis, Iopamidol exposure showed higher risk for SCI-AKI compared to Iodixanol (OR 4.5 [95% CI 1.16-17.52], p = 0.030), even after controlling for eGFR and volume of contrast medium used.

CONCLUSIONS

This study showed that intra-arterial modern contrast media administration may have a nephrotoxic effect in a population without pre-existing chronic kidney disease. Further investigations on larger scale are warranted to confirm if Iopamidol exposed patients to increased risk of SCI-AKI compared to Iodixanol.

Metformin Treatment for Patients with Diabetes and Chronic Kidney Disease: A Korean Diabetes Association and Korean Society of Nephrology Consensus Statement

The safety of metformin use for patients with type 2 diabetes mellitus (T2DM) and advanced kidney disease is controversial, and more recent guidelines have suggested that metformin be used cautiously in this group until more definitive evidence concerning its safety is available. The Korean Diabetes Association and the Korean Society of Nephrology have agreed on consensus statements concerning metformin use for patients with T2DM and renal dysfunction, particularly when these patients undergo imaging studies using iodinated contrast media (ICM). Metformin can be used safely when the estimated glomerular filtration rate (eGFR) is ≥45 mL/min/1.73 m². If the eGFR is between 30 and 44 mL/min/1.73 m², metformin treatment should not be started. If metformin is already in use, a daily dose of ≤1,000 mg is recommended. Metformin is contraindicated when the eGFR is <30 mL/min/1.73 m². Renal function should be evaluated prior to any ICM-related procedures. During procedures involving intravenous administration of ICM, metformin should be discontinued starting the day of the procedures and up to 48 hours post-procedures if the eGFR is <60 mL/min/1.73 m².

Increased circulating galectin-1 levels are associated with the progression of kidney function decline in patients undergoing coronary angiography

Galectin-1 modulates acute and chronic inflammation, and is associated with glucose homeostasis and chronic renal disease. Whether the serum galectin-1 level can predict short-term and long-term renal outcomes after contrast exposure in patients undergoing coronary angiography (CAG) remains uncertain. This study aimed to evaluate the relationship between the serum galectin-1 level and the incidence of contrast-induced nephropathy (CIN), and to investigate the predictive role of the circulating galectin-1 level for renal function decline in patients undergoing CAG. In total, 798 patients who had undergone CAG were enrolled. Baseline creatinine and serum galectin-1 levels were determined before CAG. CIN was defined as an increase in the serum creatinine level of 0.5 mg/dl or a 25% increase from baseline within 48 h after the procedure, and renal function decline was defined as > 30% reduction of the estimated glomerular filtration rate from baseline. All patients were followed for at least 1 year or until the occurrence of death after CAG. Overall, CIN occurred in 41 (5.1%) patients. During a median follow-up period of 1.4 ± 1.1 years, 80 (10.0%) cases showed subsequent renal function decline. After adjustment for demographic characteristics, kidney function, traditional risk factors, and medications, higher galectin-1 levels were found to be associated independently with a greater risk of renal function decline [tertile 2: hazard ratio (HR) 5.56, 95% confidence interval (CI) 1.79-17.22; tertile 3: HR 5.56, 95% CI 1.97-16.32], but not with CIN, regardless of the presence of diabetes. In conclusion, higher baseline serum galectin-1 levels were associated with a greater risk of renal function decline in patients undergoing CAG, but were not associated independently with CIN.

The Association of Fractional Pulse Pressure with Acute Kidney Injury in Patients Undergoing Coronary Intervention due to ST-Segment Elevated Myocardial Infarction

OBJECTIVE

Acute kidney injury (AKI), which is prevalent in ST-segment elevated myocardial infarction (STEMI) patients who have undergone primary percutaneous coronary intervention (PCI), is associated with poor cardiovascular outcomes. As high pulse pressure (PP) is associated with adverse cardiovascular events, the present study's aim was to evaluate the relationship between fractional PP (PPf) and AKI in patients with STEMI who underwent primary PCI.

SUBJECTS AND METHODS

All laboratory findings as well as echocardiographic and angiographic data of 1,170 consecutive STEMI patients were retrospectively screened. PPf was calculated from the pressures invasively measured after sheath insertion and before performing coronary angiography.

RESULTS

From 1,170 eligible STEMI patients (mean age 56 years, 18.2% female), AKI developed in 143 (12.2%) patients. The PPf and pulsatility index were significantly higher in patients with AKI than those without (0.53 ± 0.10 vs. 0.61 ± 0.10, p < 0.001, and 0.80 ± 0.03 vs. 0.82 ± 0.03, p < 0.001, respectively). PPf was also found to be associated with AKI in univariable (OR 2.183, 95% CI 1.823-2.614, p< 0.001) and multivariable (OR 1.874, 95% CI 1.513-2.322, p < 0.001) analysis. In-hospital mortality was higher in patients with AKI than those without.

CONCLUSION

Invasively measured PPf, which can be easily measured and has no additional cost in STEMI patients undergoing coronary intervention, is an independent predictor of AKI. In addition, PPf is superior to other blood pressure values and derivatives in AKI prediction.

CHA2DS2-VASC Score Predicts Risk of Contrast-Induced Nephropathy in Non-ST Elevation Myocardial Infarction Patients Undergoing Percutaneous Coronary Interventions

BACKROUND

The CHA2DS2-VASC score, used for embolic risk stratification in atrial fibrillation, has been reported recently to predict adverse clinical outcomes in patients with coronary artery disease. We investigated the correlation between the CHA2DS2-VASC score and contrast-induced nephropathy (CIN) in patients with non-ST elevation myocardial infarction (NSTEMI) who underwent percutaneous coronary intervention (PCI).

METHODS

We retrospectively enrolled 363 (191; 52.6% men) NSTEMI patients undergoing PCI. The CHA2 DS2-VASC score was calculated for each patient, and the study population was divided into 2 groups: CHA2DS2-VASC score <2 group (low score; n = 259, 71.3%) and CHA2DS2-VASC score ≥2 group (high score; n = 104, 28.6%). Patients were then reallocated to 2 groups according to the presence or absence of CIN. CIN was defined as a rise in serum creatinine >0.5 mg/dL or >25% increase in baseline within 72 h after PCI.

RESULTS

Overall, 56 cases (15.4%) of CIN were diagnosed. When patients with a CHA2DS2-VASC score of <2 were compared with those with a CHA2DS2-VASC score of ≥2, patients with a high score had a higher frequency of CIN (33) 31.7% versus (23) 8.9%; p < 0.001. Also patients with CIN had higher CHADS2 VASC score (3.94 ± 1.13 vs. 1.68 ± 0.46, p < 0.001). Additionally, in-hospital mortality, length of hospital stay, major bleeding, requirement of mechanical ventilation, and dialysis were observed significantly higher in patients with CHA2DS2-VASC score of ≥2 (p = 0.001, p = 0.002, p = 0.006, p = 0.001, p = 0.001, respectively). In receiver operating characteristic curve analysis, the area under the curve for predicting CIN was 0.702 (p < 0.001, 95% CI 0.617-0.787) and cutoff value was 2.5 (sensitivity 58.9%, specificity 76.9%) for the number of CHA2DS2-VASC score.

CONCLUSION

In NSTEMI patients undergoing PCI, CHADS2 VASC score is associated with an increased risk for CIN and in-hospital morbidity and mortality.

CHA2DS2-VASc score as a novel predictor for contrast-induced nephropathy after percutaneous coronary intervention in acute coronary syndrome

Background

CHA2DS2-VASc score, used for atrial fibrillation to assess the risk of embolic complications, have shown to predict adverse clinical outcomes in acute coronary syndrome (ACS), irrespective of atrial fibrillation. This study envisaged to assess the predictive role of CHA2DS2-VASc score for contrast-induced nephropathy (CIN) in patients with ACS undergoing percutaneous coronary intervention (PCI).

Methods

A total of 300 consecutive patients with ACS undergoing PCI were enrolled in this study. CHA2DS2-VASc score was calculated for each patient. These patients were divided into two groups as Group 1 (with CIN) and Group 2 (without CIN). CIN was defined as increase in serum creatinine level ≥0.5 mg/dL or ≥25% increase from baseline within 48 h after PCI. After receiver operating characteristic curve analysis, the study population was again classified into two groups: CHA2DS2-VASc score ≤3 group (Group A) and score ≥4 group (Group B).

Results

CIN was reported in 41 patients (13.6%). Patients with CIN had a higher frequency of hypertension, diabetes mellitus, and had a lower left ventricular ejection fraction and baseline estimated glomerular filtration rate. Receiver operating characteristic curve analysis showed good predictive value of CHA2DS2-VASc score for CIN (area under the curve 0.81, 95% CI 0.73–0.90). Patients with a CHA2DS2-VASc score of ≥4 had a higher frequency of CIN as compared with patients with score ≤3 (56.8% vs 4.8%; p = 0.0001) with multivariate analysis demonstrating CHA2DS2-VASc score of ≥4 to be an independent predictor of CIN.

Conclusion

In patients with ACS undergoing PCI, CHA2DS2-VASc score can be used as a novel, simple, and a sensitive diagnostic tool for the prediction of CIN.

Protective Effect of Phenolic Compounds Isolated from Mugwort (Artemisia argyi) against Contrast-Induced Apoptosis in Kidney Epithelium Cell Line LLC-PK1

We investigated whether 14 phenolic compounds isolated from Artemisia argyi could prevent the apoptotic damage caused by iodixanol, an iodinated contrast agent, on LLC-PK1 cells. Iodixanol was used to induce cytotoxicity in LLC-PK1 cells. Apoptotic cell death was observed as the fluorescence intensity emitted by annexin V and Hoechst 33342 stains. Western blotting was used to detect specific proteins. Seven phenolic compounds protected against iodixanol-induced LLC-PK1 cell death in a concentration-dependent manner. Among them, methyl caffeate exerted the strongest protective effect, and co-treatment with 50 and 100 μM methyl caffeate decreased intracellular reactive oxygen species elevated by 25 mg/mL iodixanol. In addition, the treatment of LLC-PK1 cells with iodixanol resulted in an increase in apoptotic cell death, which decreased by co-treatment with methyl caffeate. Iodixanol caused a cytotoxicity-related increase in the phosphorylation of extracellular-signal-regulated kinase, c-Jun N-terminal kinase, and P38; and a similar increase in the expression levels of kidney injury molecule-1 and cleaved caspase-3. However, the up-regulation of these proteins was reversed by co-treatment with methyl caffeate. These findings suggest that phenolic compounds isolated from A. argyi play an important role in protecting kidney epithelium cells against apoptotic damage caused by iodixanol.

Methods for Reducing Contrast Use and Avoiding Acute Kidney Injury During Endovascular Procedures

Iodinated Contrast Media (CM) has a plethora of applications in routine non-invasive or percutaneous invasive imaging examinations and therapeutic interventions. Unfortunately, the use of CM is not without complications, with contrast-induced acute kidney injury (CI-AKI) being among the most severe. CI-AKI is a syndrome defined as a rapid development of renal impairment after a few days of CM endovascular injection, without the presence of any other underlying related pathologies. Although mostly transient and reversible, for a subgroup of patients with comorbidities related to renal failure, CI-AKI is directly leading to longer hospitalization, elevated rates of morbidity and mortality, as well as the increased cost of funding. Thus, a need for classification in accordance with clinical and peri-procedural criteria is emerged. This would be very useful for CI-AKI patients in order to predict the ones who would have the greatest advantage from the application of preventive strategies. This article provides a practical review of the recent evidence concerning CI-AKI incidence, diagnosis, and sheds light on prevention methods for reducing contrast use and avoiding AKI during endovascular procedures. In conclusion, despite the lack of a specific treatment protocol, cautious screening, assessment, identification of the high-risk patients, and thus the application of simple interventions -concerning modifiable risk factors- can significantly reduce CI-AKI risk.

Contrast Media-Induced Nephropathy in Patients with Unruptured Cerebral Aneurysm After Coiling Endovascular Treatment

BACKGROUND

The endovascular coiling procedure to treat cerebral aneurysms using contrast media has become more popular. However, studies of the incidence of, and risk factors for, contrast media-induced nephropathy (CIN) after coiling procedures have been limited. Thus, we evaluated the incidence and risk factors for CIN in patients who had undergone cerebral aneurysmal coiling procedures.

METHODS

We retrospectively reviewed the electric medical records of 380 patients who had undergone cerebral aneurysmal coiling treatment under general anesthesia. CIN was defined as an absolute increase in serum creatinine (≥0.5 mg/dL) or a relative increase (≥25%) in the baseline serum creatinine value at 48-72 hours after exposure to a contrast agent.

RESULTS

Elective cerebral aneurysmal coiling procedures were performed in 230 patients. Of the 230 patients, CIN developed in 13 (5.6%). The presence of diabetes mellitus (30.8% vs. 9.7%; P = 0.040) and patient age >75 years (30.8% vs. 6.5%; P = 0.012) were risk factors for CIN.

CONCLUSIONS

Our study has demonstrated that the incidence of CIN in patients undergoing elective cerebral aneurysmal coiling procedures is ∼6.0%. We also identified underlying diabetes mellitus and advanced age (≥75 years) as potential risk factors.

Circulating Fibroblast Growth Factor 21 is Associated with Subsequent Renal Injury Events in Patients Undergoing Coronary Angiography

Fibroblast growth factor 21 (FGF21) is a regulator of glucose homeostasis, and is suggested to have protective effect on diabetic nephropathy. Its impact on non-diabetic kidney disease is unclear. To investigate the impact of FGF21 on contrast-induced nephropathy (CIN), 531 subjects underwent elective coronary angiography (CAG) were enrolled. Baseline creatinine and FGF21 were obtained before CAG. Patients were grouped into tertiles according to their FGF21 concentration. Creatinine was obtained 48 hours after CAG, and every 6 months in the follow-up period. Renal function decline was defined as >30% reduction of eGFR from baseline. All subjects were followed up till December 2016, or till the occurrence of major adverse cardiovascular events (MACE). Patients with higher FGF21 concentration were older, had higher incidence of hypertension, diabetes, chronic kidney disease, and heart failure. Thirty-four cases of CIN and 111 cases of renal function decline were identified during mean follow-up of 2.3 ± 1.3 years. Circulating FGF21 level was independently associated with CIN (aOR: 4.66, 95% CI: 1.29–16.86, p = 0.019) and renal function decline (aHR: 7.98, 95% CI: 4.07–15.66, p < 0.001) whether diabetes was present or not. In conclusion, circulating FGF21 level is independently associated with the incidence of CIN and subsequent kidney injury in patients undergoing CAG.

Iodixanol versus iopromide in patients with renal insufficiency undergoing coronary angiography with or without PCI

BACKGROUND

The use of contrast agents during coronary angiography can result in contrast-induced nephropathy (CIN), particularly in patients with renal dysfunction. On the contrary, different contrast agents can induce different degree of changes in cardiac function. The objective of our meta-analysis was to compare the clinical safety of iso-osmolar contrast medium iodixanol to low-osmolar contrast medium iopromide in patients with renal insufficiency undergoing coronary angiography with or without percutaneous coronary intervention (PCI).

METHODS

We searched Medline, Embase, Cochrane Library, and reference lists to identify randomized controlled trials that compared iodixanol to iopromide with the incidence of CIN as an endpoint in renal impaired patients undergoing coronary angiography. Outcome measures were the incidence of CIN, absolute peak serum creatinine (Scr) increase from baseline and a composite of cardiovascular adverse events.

RESULTS

A total of 8 trials with 3532 patients were pooled; 1759 patients received iodixanol and 1773 patients received iopromide. There was no significant difference in the incidence of CIN (summary odds ratio [OR] 0.50, 95% confidence interval [CI] 0.19-1.35, P = .17) and peak Scr increase (mean difference -0.01 mg/dL, 95% CI -0.08 to 0.05, P = .69) when iodixanol was compared with iopromide. But iodixanol was associated with a statistically significant reduction in cardiovascular adverse events when compared with iopromide (OR 0.47, 95% CI 0.30-0.73, P = .0009).

CONCLUSIONS

Analysis of pooled data from 8 randomized controlled trials of iodixanol against iopromide in patients with renal insufficiency undergoing coronary angiography with or without PCI showed that iodixanol nonsignificantly reduced the incidence of CIN, but was associated with a significantly reduced risk of cardiovascular adverse events when compared with iopromide.

Contrast-Induced Nephropathy Is Less Common in Patients with Good Coronary Collateral Circulation

Background/Aims

Contrast-induced nephropathy (CIN) is a typically reversible type of acute renal failure that develops after exposure to contrast agents; underlying endothelial dysfunction is thought to be an important risk factor for CIN. Although the mechanism of coronary collateral circulation (CCC) is not fully understood, a pivotal role of the endothelium has been reported in many studies. The aim of this study was to investigate whether there is a relationship between CCC and CIN.

Methods

Patients with at least one occluded major coronary artery and blood creatinine analyses performed before and on the second day after angiography were included in the study. CIN was defined as a 25% or greater elevation of creatinine on the second day after exposure to the contrast agent. Collateral grading was performed according to the Rentrop classification. Patients were grouped according to whether they developed CIN or not, i.e., CIN(-) and CIN(+) group.

Results

A total of 214 patients who met the inclusion criteria were included in the study. CIN was diagnosed in 43 patients (20.1%) in the study population. Good CCC was identified in 112 patients (65.5%) in the CIN(-) group, whereas it was identified in 13 patients (30.2%) in the CIN(+) group. In the CIN(-) group, good CCC was significantly more frequent (p < 0.001). Furthermore, collateral circulation was an independent predictor of CIN.

Conclusion

Good collateral circulation was associated with a lower frequency of CIN, and poor collateral circulation was an independent predictor of CIN.

Effect of iodinated contrast media on renal perfusion: A randomized comparison study in pigs using quantitative contrast-enhanced ultrasound (CEUS)

The administration of iodinated contrast media (CM) can cause microcirculatory disorder leading to acute renal dysfunction. In a prospective, randomized investigation two CM (Iodixanol vs Iopromide) were compared in 16 pigs. Each animal received 10 intra-aortal injections (5 ml Iodixanol or 4.32 ml Iopromide). Microcirculation was assessed using contrast-enhanced ultrasound (CEUS) directly on the kidney surface using time-to-peak (TTP) and blood-volume-analysis. Macroscopic observations were documented. Post mortem residual CM distribution in the kidneys was detected using X-ray. TTP was significantly prolonged over the descending vasa recta of the Iopromide group. This coincided with a visible marble-like pattern on the kidney surface occurring in 30 out of 80 Iopromide-injections but in 4 out of 80 Iodixanol-injections (p = 0.007). The blood volume over the entire kidney did not change after Iodixanol-application, but decreased by about 6.1% after Iopromide-application. The regional blood volume in the renal cortex showed a tendency to decrease by about 13.5% (p = 0.094) after Iodixanol-application, and clearly decreased by about 31.7% (p = 0.022) after Iopromide-application. The study revealed a consistent influence of repeated injections of two different CM on the kidney perfusion using three different imaging methods (CEUS analysis, macroscopic observation and X-ray analysis).

Predictors of acute kidney injury in patients admitted with ST-elevation myocardial infarction - results from the Bremen STEMI-Registry

BACKGROUND:

Deterioration of renal function after exposition to contrast media is a common problem in patients with myocardial infarction undergoing percutaneous coronary interventions. The aim of the present study was to assess the incidence of acute kidney injury in patients admitted with ST-elevation-myocardial infarction (STEMI) and its association with infarction severity, comorbidities and treatment modalities, including amount of contrast media applied.

METHODS:

All patients with STEMI from the metropolitan area of Bremen, Germany are treated at the Bremen Heart Centre and since 2006 documented in the Bremen STEMI-Registry. Acute kidney injury was graded from stage 0 to 3 following the Kidney-disease-improving-global outcomes criteria from 2012.

RESULTS:

Data from 3810 patients admitted with STEMI were included in this study. No acute kidney injury was observed in 3120 (82%) patients while acute kidney injury was detected in 690 (18%) patients: Stage 1: n=497 (13%), 2: n=66 (2%), 3: n=127 (3%). Acute kidney injury was associated with elevated 30-day (0: 3%, 1: 20%, 2: 46%, 3: 58%) and one-year mortality rates (0: 6%, 1: 26%, 2: 49%, 3: 66%). Higher acute kidney injury stages were associated with higher peak creatine kinase (in U/l±SEM): stage 0: 1748±33, 1: 2588±127, 2: 3684±395, 3: 3330±399, p (<0.01), lower mean systolic blood pressure at admission (in mmHG±SD): 0: 133±28, 1: 129±31; 2: 121±31, 3: 115±33 ( p<0.01) and higher Thrombolysis in Myocardial Infarction risk score for STEMI (scale 0-14±SD): 0: 2.71±2, 1: 4.08±2, 2: 4.98±2, 3: 5.05±2, ( p<0.01). However, no such association could be found between acute kidney injury stage and amount of contrast media applied (in ml±SD) 0: 138±57, 1: 139±61; 2: 140±76; 3: 145±80 ( p=0.5). Reduced initial glomerular filtration rate was associated with higher incidences of acute kidney injury while again no relation to amount of contrast media could be observed in subgroups ranked by initial glomerular filtration rate. A multivariate analysis confirmed these results: while left-heart-failure/cardiogenic shock (odds ratio (OR) 4.2, 95% confidence interval (CI) 3.3-5.5) as well as larger infarctions (peak creatine kinase >3000 U/l (OR 2.2, 95% CI 1.7-2.8)) were independently associated with a greater risk for acute kidney injury, amount of contrast media applied during angiography was not (150-250 ml, OR 0.95, 95% CI 0.8-1.2 ( p=0.7), >250 ml, OR 1.3, 95% CI 0.8-2.0 ( p=0.5)).

CONCLUSIONS:

Acute kidney injury, which was associated with elevated short- and long-term mortality rates, could be observed in 18% of patients admitted with STEMI. The present data suggest that severity and haemodynamic impairment due to STEMI rather than contrast-media-induced nephropathy is the key contributor for acute kidney injury in STEMI patients. The deleterious effect of the myocardial infarction itself on renal function can be explained through renal hypoperfusion, neurohormonal activation or other pathomechanisms that might have been underestimated in the past.

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.

Predictive Value of CHA2DS2-VASC Score for Contrast-Induced Nephropathy After Percutaneous Coronary Intervention for Acute Coronary Syndrome

The CHA2DS2-VASC score, used for embolic risk stratification in atrial fibrillation (AF), has been reported recently to predict adverse clinical outcomes in patients with acute coronary syndrome (ACS), regardless of having AF. We investigated the correlation between the CHA2DS2-VASC score and contrast-induced nephropathy (CIN) in patients with ACS who underwent urgent percutaneous coronary intervention (PCI). A total of 1,408 patients were enrolled in the study. The CHA2DS2-VASC score was calculated for each patient. Based on the receiver operating characteristic analysis, the study population was divided into 2 groups: CHA2DS2-VASC score ≤3 group (n = 944) and CHA2DS2-VASC score ≥4 group (n = 464). Patients were then reallocated to 2 groups according to the presence or absence of CIN. CIN was defined as a rise in serum creatinine >0.5 mg/dl or >25% increase in baseline within 72 hours after PCI. Overall, 159 cases (11.3%) of CIN were diagnosed. Receiver operating characteristic curve analysis revealed good diagnostic value of CHA2DS2-VASC score in predicting CIN (area under the curve 0.769, 95% confidence interval 0.733 to 0.805; p <0.001). When patients with a CHA2DS2-VASC score of ≥4 were compared with those with a CHA2DS2-VASC score of ≤3, patients with high score had a higher frequency of CIN (23.9% vs 5.1%; p <0.001), and multivariate analysis identified the CHA2DS2-VASC score of ≥4 as an independent predictor of CIN. In conclusion, CHA2DS2-VASC score can be used as a new, simple, and reliable tool to predict CIN in patients with ACS who underwent urgent PCI.

Effect of radiographic contrast media on renal perfusion - First results

BACKGROUND

Intra-arterial administration of radiographic contrast media (CM) is discussed to impair renal perfusion. The pathogenesis of contrast-induced Nephropathy (CIN) is still not clarified.

OBJECTIVE

This trial was performed to prove the effects of two CM with different molecular structure on renal perfusion.

METHODS

A prospective, randomized study on 16 pigs was designed to compare the outcome after application of a low-osmolar iodinated CM (770 mOsm/kg H2O - Group1) and an iso-osmolar iodinated CM (290 mOsm/kg H2o - Group2).Color Coded Doppler Sonography (LOGIQ E9, GE, Milwaukee, USA) was applied for measuring the Renal Resistive Index (RRI) before and after the first, fifth, and tenth bolus of CM. Statistics was performed using analysis of variance for repeated measurements with the Factor "CM".

RESULTS

All flow spectra were documented free of artifacts and Peak Systolic Velocity (PSV), Enddiastolic Velocity (EDV) and RRI respectively could be calculated. Mean PSV in Group 1 led to a decrease while in Group 2 PSV showed a significant increase after CM (p = 0,042). The course of the mean EDV in both groups deferred accordingly (p = 0,033). Mean RRI over time significantly deferred in both groups (p = 0,001). It showed a biphasic course in Group 2 and a decrease over time in Group 2.

CONCLUSION

While iso-osmolar CM induced an increase of PSV and EDV together with a decrease of RRI, low-osmolar CM could not show this effect or rather led to the opposite.

Histopathological Evaluation of Contrast-Induced Acute Kidney Injury Rodent Models

Contrast-induced acute kidney injury (CI-AKI) can occur in 3–25% of patients receiving radiocontrast material (RCM) despite appropriate preventive measures. Often patients with an atherosclerotic vasculature have to receive large doses of RCM. Thus, animal studies to uncover the exact pathomechanism of CI-AKI are needed. Sensitive and specific histologic end-points are lacking; thus in the present review we summarize the histologic appearance of different rodent models of CI-AKI. Single injection of RCM causes overt renal damage only in rabbits. Rats and mice need an additional insult to the kidney to establish a clinically manifest CI-AKI. In this review we demonstrate that the concentrating ability of the kidney may be responsible for species differences in sensitivity to CI-AKI. The most commonly held theory about the pathomechanism of CI-AKI is tubular cell injury due to medullary hypoxia. Thus, the most common additional insult in rats and mice is some kind of ischemia. The histologic appearance is tubular epithelial cell (TEC) damage; however severe TEC damage is only seen if RCM is combined by additional ischemia. TEC vacuolization is the first sign of CI-AKI, as it is a consequence of RCM pinocytosis and lysosomal fusion; however it is not sensitive as it does not correlate with renal function and is not specific as other forms of TEC damage also cause vacuolization. In conclusion, histopathology alone is insufficient and functional parameters and molecular biomarkers are needed to closely monitor CI-AKI in rodent experiments.

Crucial Roles of Systemic and Tissue Lipid Peroxidation Levels and Anti-Oxidant Defences Following Contrast Agent Application

Background

One of the most important side effects of contrast pharmaceutical agents, which are used very common in routine radiology practice, is contrast induced nephropathy. Even ischemia, oxidative stress and osmolality related cytotoxic effects are considered, the molecular mechanisms underlying this pathology have not been identified completely yet.

Objectives

The aim of the current study was to reveal the role of oxidative stress and antioxidant enzymatic defence mechanisms in the aetiopathogenesis of contrast-induced nephropathy. We also studied possible alleviating effects of N-acetylcysteine (NAC), a potent antioxidant, to obtain extra information regarding the molecular mechanisms underlying this pathology.

Materials and Methods

This is an clinical-experimental study, This study was conducted of Istanbul/Turkey between September 15, 2012 and April 15, 2013. Three groups of male rats were randomly set up as a control group (C), a 100 mg/kg intraperitoneal NAC + 7 mL/kg contrast agent group (N + CIN) and a 7 mL/kg intraperitoneal contrast agent group (CIN). They were placed in individual metabolic cages 48 hours after agent administration to obtain 24-hour urine samples. Renal function tests (albumin, urea, creatinine, total protein) were conducted, oxidative stress parameters (Cu, Zn superoxide dismutase activity - Cu, Zn-SOD; advanced oxidation protein products - AOPP; protein carbonyls - PCO; total thiol groups - T-SH; and lipid hydroperoxides -LHP) were measured and tissues were analysed histopathologically.

Results

Compared with the control group, groups CIN and N + CIN had significantly higher urea and LHP levels (P < 0.05 and P < 0.001, respectively) and significantly lower Cu, Zn-SOD activity and creatinine clearance (P < 0.05). There was no statistically significant difference between the groups in PCO or AOPP levels despite differences in descriptive statistics.

Conclusions

Contrast-agent-induced nephropathic changes are more closely related to the magnitude of lipid peroxidation than protein oxidation.

CHADS2 score predicts risk of contrast-induced nephropathy in stable coronary artery disease patients undergoing percutaneous coronary interventions

BACKGROUND/PURPOSE

To investigate the correlation between the CHADS2 score and risk of contrast-induced nephropathy (CIN), we conducted a retrospective study in patients who underwent elective percutaneous coronary intervention (PCI) and compared its accuracy with previous scoring systems.

METHODS

A total of 539 patients who underwent elective PCI were enrolled. Based on their underlying diseases, such as hypertension, diabetes, and kidney disease, CHADS2 score, R2CHADS2 score, and Mehran's risk score were calculated for each patient. Incidence of CIN was defined as a rise in serum creatinine >0.5 mg/dL or >25% increase in baseline within 48 hours after PCI. All study participants were followed up until October 2014, or until the occurrence of major adverse cardiovascular events (MACEs).

RESULTS

Overall, 55 cases (10.2%) of CIN and 90 cases (16.7%) of MACEs were identified after participants were followed up for 1.57 ± 1.46 years. The study cohort was divided into three groups according to CHADS2 scores: score 0, score 1-2, and score 3-6. In multivariate analysis, an increase of 1 point in the CHADS2 score was independently associated with a 37% increase in the risk of CIN (odds ratio, 1.37; 95% confidence interval, 1.00-1.87; p = 0.048) and a 49% increase in MACEs (hazard ratio, 1.49; 95% confidence interval, 1.18-1.88, p = 0.001). In pairwise comparison, the discriminatory performance of CHADS2 score was not inferior to either R2CHADS2 score (p = 0.226) or Mehran's risk score (p = 0.075).

CONCLUSION

CHADS2 score could be a simple and useful predictor for CIN in patients undergoing elective PCI.

Preventing Contrast-induced Renal Failure: A Guide

Contrast-induced acute kidney injury (CI-AKI) is characterised by a rapid deterioration of renal function within a few days of parenteral administration of contrast media (CM) in the absence of alternative causes. CI-AKI is the most common form of iatrogenic kidney dysfunction with an estimated prevalence of 12 % in patients undergoing percutaneous coronary intervention. Although usually self-resolving, in patients with pre-existing chronic kidney disease (CKD) or concomitant risk factors for renal damage, CI-AKI is associated with increased short-and long-term morbidity and mortality. Therefore, risk stratification based on clinical and peri-procedural characteristics is crucial in selecting patients at risk of CI-AKI who would benefit the most from implementation of preventive measures.

Serum hyperchloremia as a risk factor for acute kidney injury in patients with ST-segment elevation myocardial infarction undergoing percutaneous coronary intervention

A high serum chloride concentration has been associated with the development of acute kidney injury in critically ill patients. However, the association between hyperchloremia and acute kidney injury (AKI) in patients admitted with ST-segment elevation myocardial infarction (STEMI) treated with percutaneous coronary intervention (PCI) is unknown. A retrospective analysis of consecutive patients admitted with the diagnosis of STEMI and treated with PCI was performed. Subjects were classified as having hyper- or normochloremia based upon their admission serum chloride level. Multivariable logistic regression analyses were employed for the primary and secondary outcomes. The primary analysis evaluated whether high serum chloride on admission was associated with the development of AKI after adjusting for age, diabetes mellitus, admission systolic blood pressure, contrast volume used during angiography, Killip class, and need for vasopressor therapy or intraaortic balloon pump. The secondary analyses evaluated whether high serum chloride was associated with sustained ventricular tachycardia or fibrillation. Of 291 patients (26.1% female, mean age of 59.9 ± 12.6 years, and mean body mass index of 29.3 ± 6.1 kg/m(2)), 25 (8.6%) developed AKI. High serum chloride on admission did not contribute significantly to the development of AKI (odds ratio, 95%; confidence interval, 0.90 to 1.24). In addition, serum chloride on admission was not significantly associated with sustained ventricular tachycardia or fibrillation after adjusting for demographic and clinical covariates. In conclusion, our study demonstrated no association between baseline serum hyperchloremia and an increased risk of AKI in patients admitted with STEMI treated with PCI.

Resveratrol alleviates the cytotoxicity induced by the radiocontrast agent, ioxitalamate, by reducing the production of reactive oxygen species in HK-2 human renal proximal tubule epithelial cells in vitro

Radiocontrast-induced nephropathy (RIN) is one of the leading causes of hospital-acquired acute kidney injury (AKI). The clinical strategies currently available for the prevention of RIN are insufficient. In this study, we aimed to determine whether resveratrol, a polyphenol phytoalexin, can be used to prevent RIN. For this purpose, in vitro experiments were performed using a human renal proximal tubule epithelial cell line (HK-2 cells). Following treatment for 48 h, the highly toxic radiocontrast agent, ioxitalamate, exerted cytotoxic effects on the HK-2 cells in a concentration-dependent manner, as shown by MTT assay. The half maximal inhibitory concentration (IC50) was found to be approximately 30 mg/ml. Flow cytometry also revealed a marked increase in the number of apoptotic cells following exposure to ioxitalamate. In addition, the number of necrotic, but not necroptotic cells was increased. However, treatment with resveratrol (12.5 µM) for 48 h significantly alleviated ioxitalamate (30 mg/ml)-induced cytotoxicity, by reducing cytosolic DNA fragmentation, increasing the expression of the anti-apoptotic protein, Bcl-2 (B-cell lymphoma 2), and survivin, activating caspase-3, preventing autophagic death and suppressing the production of reactive oxygen species (ROS). Resveratrol also suppressed the ioxitalamate-induced formation of 8-hydroxy-2'-deoxyguanosine (8-OHdG), a biomarker of oxidative DNA damage. N-acetylcysteine (NAC), a ROS scavenger commonly used to prevent RIN, also reduced ioxitalamate-induced cytotoxicity, but at a high concentration of 1 mM. Sirtuin (SIRT)1 and SIRT3 were not found to play a role in these effects. Overall, our findings suggest that resveratrol may prove to be an effective adjuvant therapy for the prevention of RIN.

Outcome Differences between Intra-Arterial Iso- and Low-Osmolality Iodinated Radiographic Contrast Media in the Interventional Management of Stroke III Trial

BACKGROUND AND PURPOSE

Intracarotid arterial infusion of nonionic, low-osmolal iohexol contrast medium has been associated with increased intracranial hemorrhage in a rat middle cerebral artery occlusion model compared with saline infusion. Iso-osmolal iodixanol (290 mOsm/kg H2O) infusion demonstrated smaller infarcts and less intracranial hemorrhage compared with low-osmolal iopamidol and saline. No studies comparing iodinated radiographic contrast media in human stroke have been performed, to our knowledge. We hypothesized that low-osmolal contrast media may be associated with worse outcomes compared with iodixanol in the Interventional Management of Stroke III Trial (IMS III).

MATERIALS AND METHODS

We reviewed prospective iodinated radiographic contrast media data for 133 M1 occlusions treated with endovascular therapy. We compared 5 prespecified efficacy and safety end points (mRS 0-2 outcome, modified TICI 2b-3 reperfusion, asymptomatic and symptomatic intracranial hemorrhage, and mortality) between those receiving iodixanol (n = 31) or low-osmolal contrast media (n = 102). Variables imbalanced between iodinated radiographic contrast media types or associated with outcome were considered potential covariates for the adjusted models. In addition to the iodinated radiographic contrast media type, final covariates were those selected by using the stepwise method in a logistic regression model. Adjusted relative risks were then estimated by using a log-link regression model.

RESULTS

Of baseline or endovascular therapy variables potentially linked to outcome, prior antiplatelet agent use was more common and microcatheter iodinated radiographic contrast media injections were fewer with iodixanol. Relative risk point estimates are in favor of iodixanol for the 5 prespecified end points with M1 occlusion. The percentage of risk differences are numerically greater for microcatheter injections with iodixanol.

CONCLUSIONS

While data favoring the use of iso-osmolal iodixanol for reperfusion of M1 occlusion following IV rtPA are inconclusive, potential pathophysiologic mechanisms suggesting clinical benefit warrant further investigation.

Which iodinated contrast media is the least cytotoxic to human disc cells?

BACKGROUND

Iodinated contrast media (CM) is commonly used for various intradiscal injections such as in discography and endoscopic spinal surgery. However, CM has been shown to be toxic to renal tissue due to its ionic strength and osmolarity and as a result of iodine-induced cytotoxicity, which has raised concern over whether there are similar negative effects on disc cells.

PURPOSE

This in vitro study was designed to identify the least cytotoxic iodinated CM to the human disc cell among four different physiochemical iodinated contrast dyes.

STUDY DESIGN

In vitro laboratory study.

METHODS

Intervertebral disc tissue was obtained by discectomy from a total of 10 lumbar disc patients undergoing surgery and disc cells were isolated. The human disc cells were grown in 3D alginate bead culture with 0, 0.1, 10, and 100 mg/mL CM solutions (ionic dimer, ionic monomer, non-ionic dimer, and non-ionic monomer) and mannitol as a control for 2 days. The living cells were analyzed with trypan blue staining. Fluorescence-activated cell sorting analysis was performed using Annexin V and propidium iodide (PI) and 3D alginate bead immunostaining to identify live, apoptotic, and necrotic cells.

RESULTS

Human disc cell death was time- and dose-dependent in response to CM and more necrosis was observed than apoptosis. In addition, non-ionic dimeric CM (iodixanol) showed the least toxic effect on human disc cells, followed by non-ionic monomeric (iopromide), ionic dimeric (ioxaglate), and ionic monomeric CM (ioxithalamate).

CONCLUSIONS

Contrast media is cytotoxic to human disc cells in a dose- and time-dependent manner. This in vitro study revealed that, among four different CM preparations, non-ionic dimeric CM is the least detrimental to human disc cell viability. Careful attention should be paid to the type of CM chosen for discography and endoscopic spinal surgery. It is also necessary to investigate the detrimental effects of CM on disc cells and disc degeneration in further in vivo studies.

The effect of radiographic contrast media on reperfusion injury in the isolated rat heart

Background and Objectives

We investigated the effects of commonly used contrast media (CM) on myocardial ischemia-reperfusion injury in isolated rat hearts.

Subjects and Methods

Isolated rat hearts were subjected to 30 minutes of regional ischemia and 2 hours of reperfusion. The following CM (1 mL/1 L Krebs-Henseleit buffer) were randomly perfused for 15 minutes beginning 5 minutes before reperfusion and ending 10 minutes after reperfusion: iohexol (n=8), iopromide (n=8), ioversol (n=8), iomeprol (n=8), iopamidol (n=7), ioxaglate (n=8), and iodixanol (n=7). The effects of a direct bolus injection of undiluted iohexol, iopromide, or ioxaglate (each n=6) via the aortic root immediately prior to reperfusion were also evaluated. The area of necrosis, expressed as the percentage of the area at risk (AN/AR), and cardiodynamic variables were measured.

Results

The AN/AR of the control and experimental groups in the order described in methods was 33.7±6.4%, 30.3±7.4%, 34.7±12.6%, 29.2±10.2%, 20.9±7.6%, 22.6±8.7%, 18.8±7.9%, and 19.9±11.4%, respectively. Groups that received iomeprol and ioxaglate exhibited significantly decreased AN/AR values compared to those of control hearts (p=0.042 and p=0.013). No significant differences in the AN/AR were observed between control hearts and the groups injected with a single bolus of CM. No significant hemodynamic changes were noted after reperfusion among the groups.

Conclusion

The overall effects of the CM on coronary reperfusion were not deleterious, and better effects were noted in two CM groups. However, it is unclear whether this result was attributed to a specific physiochemical property of the CM.