Contrast medium-induced nephropathy: The pathophysiology

Effects of gadolinium (Gd) and a Gd-based contrast agent (GBCA) on early life stages of zebrafish (Danio rerio)

Gadolinium (Gd) is one of the rare earth elements (REY) and is widely used in magnetic resonance imaging (MRI) contrast agents. Anthropogenic Gd enrichment has frequently been found in wastewater treatment plant effluents in industrialised countries, rising concerns regarding effects on aquatic biota. This study investigates the acute toxicity and sublethal effects of Gd in two forms, as inorganic salt (GdCl3) and as Gd-based contrast agent (GBCA), on early life stages of zebrafish (Danio rerio). Nominal exposure concentrations ranged from 3 to 3000 μg L-1, with an exposure duration of 96 h. None of the two tested compounds were acutely toxic to embryos and larvae. Similarly, we did not observe any effects on larval development and locomotive behaviour. However, we found significant changes in the brain activity of larvae exposed to the highest concentrations of GdCl3 and the GBCA. Our findings show that Gd can have sublethal effects on developing fish at lower concentrations than reported previously, highlighting the necessity of investigating the long-term fate and effects of GBCAs released into the aquatic environment.

Gamma glutamyl transferase as a biomarker to predict contrast-induced nephropathy among patients with acute coronary syndrome undergoing coronary interventions: a meta-analysis

The third most frequent reason for hospitalized acute kidney injury is contrast-induced nephropathy (CIN). Percutaneous coronary intervention (PCI) and coronary angiography (CAG) are two interventions that can result in CIN. In this study, we sought to determine how well gamma-glutamyl transferase (GGT) can predict CIN following CAG and PCI.

Method

Two researchers searched through PubMed, Scopus, and Web of Science in November 2022 to find articles that examined GGT levels in CIN patients following PCI or CAG. To rate the quality of the studies, the Joanna Briggs Institute Critical Appraisal Checklist was employed. The Cochran test and I2 statistics were utilized to assess study heterogeneity. To calculate the number of participants required to reject the null hypothesis, power analysis was used. We evaluated the epidemiologic strength of the results using the Grading of Recommendations Assessment, Development, and Evaluation (GRADE). The authors used Comprehensive Meta-analysis Version 3 to summarize the results.

Results

GGT was shown to be considerably greater in patients with CIN according to the meta-analysis's findings (odds ratio: 3.21, 95% CI: 1.26-8.15, P=0.014); nevertheless, the findings were accompanied by significant heterogeneity (I2=91.93%, P<0.001). Although the relationship between CIN and GGT was power full regarding power analysis (1- β =1, number of effect sizes=4, the average number per group=336), very low quality of evidence was observed regarding GRADE criteria.

Conclusions

These results suggest the GGT level may be a predictor of contrast-induced nephropathy in patients having cardiac catheterization; however, more research is required to prove the epidemiological validity.

The Effect of SGLT2 Inhibitors on the Development of Contrast-Induced Nephropathy in Diabetic Patients with Non-ST Segment Elevation Myocardial Infarction

Background and Objectives: Percutaneous procedures using contrast agents are modern diagnosis and treatment methods for cardiovascular diseases. Contrast use may cause nephropathy, especially in diabetic patients. SGLT2 inhibitors have strong cardioprotective and renal protective effects. In our study, we investigated the effectiveness of this drug group in preventing the development of Contrast-Induced Nephropathy (CIN). Materials and Methods: The results of 312 diabetic patients who underwent CAG were analyzed. The study group included 104 DM patients using SGLT2 and the control group did not use SGLT2. These groups were compared with each other in terms of clinical, demographic, and laboratory parameters. Results: The groups were similar characteristics. However, post-CAG creatinine values compared with before the procedure, the development of CIN was observed to be significantly less in the group using SGLT2 inhibitor (p = 0.03). When the results of the multivariate analysis were examined, it was seen that the use of SGLT2 inhibitors significantly reduced the risk of CIN (odds ratio (OR): 0.41, 95% confidence interval (CI): 0,142-0.966, p = 0.004). Conclusions: Our study showed that SGLT2 inhibitors may be protective against the development of CIN, especially in patients with comorbid conditions such as diabetes.

Investigation of the Effects of Stress Hyperglycemia Ratio and Preoperative Computed Tomographic Angiography on the Occurrence of Acute Kidney Injury in Diabetic Patients following Surgical Thromboembolectomy

Acute lower extremity ischemia (ALI) is a cardiovascular emergency resulting from embolic and thrombotic causes. Although endovascular techniques have advanced, surgical thromboembolectomy is still the gold standard. Emergency thromboembolectomy surgery involves an ischemia-reperfusion injury, which also poses a risk for acute renal injury (AKI). The stress hyperglycemia rate (SHR) has recently emerged as an important prognostic value in emergency cardiovascular events. In the present study, we aimed to analyze the impact of preoperative contrast-enhanced tomographic angiography (CTA) and the SHR value on postoperative AKI in emergency thromboembolectomy procedures in patients with insulin-dependent diabetes mellitus (DM). In this retrospective analysis, patients with DM who received emergency surgical thromboembolectomy after being hospitalized at our hospital with ALI between 20 October 2015, and 10 September 2022, were included. Patients were classified into two groups: Group 1 (N = 159), who did not develop AKI, and Group 2 (N = 45), who did. The 45 patients in Group 2 and the 159 patients in Group 1 had median ages of 59 (39-90) and 66 (37-93), respectively (p = 0.008). The percentage of patients in Group 2 with Rutherford class IIB and admission times longer than 6 h was higher (p = 0.003, p = 0.027, respectively). To determine the variables affecting AKI after surgical embolectomy procedures, multivariate logistic regression analysis was used. In multivariate analysis Model 1, age > 65 years (odds ratio [OR]: 1.425, 95% confidence interval [CI]: 1.230-1.980, p < 0.001), preoperative high creatinine (OR: 4.194, 95% CI: 2.890-6.156, p = 0.003), and Rutherford class (OR: 0.874, 95% CI: 0.692-0.990, p = 0.036) were determined as independent predictors for AKI. In Model 2, age > 65 years (OR: 1.224 CI: 1.090-1.679, p = 0.014), preoperative high creatinine (OR: 3.975, 95% CI: 2.660-5.486, p = 0.007), and SHR (OR: 2.142, CI: 1.134-3.968, p = 0.003), were determined as independent predictors for amputation. In conclusion, when an emergency thromboembolectomy operation is planned in insulin-dependent DM patients, renal risky groups can be identified, and renal protective measures can be taken. In addition, to reduce the renal risk, according to the suitability of the clinical conditions of the patients, the decision to perform a CTA with contrast can be taken by looking at the SHR value.

Calorie Restriction Protects against Contrast-Induced Nephropathy via SIRT1/GPX4 Activation

Calorie restriction (CR) extends lifespan and increases resistance to multiple forms of stress, including renal ischemia-reperfusion (I/R) injury. However, whether CR has protective effects on contrast-induced nephropathy (CIN) remains to be determined. In this study, we evaluated the therapeutic effects of CR on CIN and investigated the potential mechanisms. CIN was induced by the intravenous injection of iodinated contrast medium (CM) iopromide (1.8 g/kg) into Sprague Dawley rats with normal food intake or 40% reduced food intake, 4 weeks prior to iopromide administration. We found that CR was protective of CIN, assessed by renal structure and function. CM increased apoptosis, reactive oxygen species (ROS), and inflammation in the renal outer medulla, which were decreased by CR. The silent information regulator 1 (SIRT1) participated in the protective effect of CR on CIN, by upregulating glutathione peroxidase 4 (GPX4), a regulator of ferroptosis, because this protective effect was reversed by EX527, a specific SIRT1 antagonist. Our study showed that CR protected CIN via SIRT1/GPX4 activation. CR may be used to mitigate CIN.

Pediatric onco-nephrology: time to spread the word : Part I: early kidney involvement in children with malignancy

Onco-nephrology has been a growing field within the adult nephrology scope of practice. Even though pediatric nephrologists have been increasingly involved in the care of children with different forms of malignancy, there has not been an emphasis on developing special expertise in this area. The fast pace of discovery in this field, including the development of new therapy protocols with their own kidney side effects and the introduction of the CD19-targeted chimeric antigen receptor T cell (CAR-T) therapy, has introduced new challenges for general pediatric nephrologists because of the unique effects of these treatments on the kidney. Moreover, with the improved outcomes in children receiving cancer therapy come an increased number of survivors at risk for chronic kidney disease related to both their cancer diagnosis and therapy. Therefore, it is time for pediatric onco-nephrology to take its spot on the expanding subspecialties map in pediatric nephrology.

[Contrast medium-induced acute kidney injury-Consensus paper of the working group "Heart and Kidney" of the German Cardiac Society and the German Society of Nephrology]

This consensus paper summarizes the expert consensus and recommendations of the working group "Heart and Kidney" of the German Cardiac Society (DGK) and the German Society of Nephrology (DGfN) on contrast medium-induced acute kidney injury. Potentially nephrotoxic contrast agents containing iodine are frequently used in interventional medicine and for computer tomography diagnostics. Acute kidney injury occurs in approximately 8-17% of patients exposed to contrast media. The risk factors and underlying pathophysiology are discussed and recommendations for the prophylaxis and treatment of contrast medium-induced acute nephropathy are presented.

Image quality in dual-source multiphasic dynamic computed tomography of the abdomen: evaluating the effects of a low tube voltage (70 kVp) in combination with contrast dose reduction

PURPOSE

To compare the image quality of multiphasic (arterial, portal, and equilibrium phases) dynamic computed tomography (CT) of the abdomen obtained by a low tube voltage (70kVp) in combination with a half-dose iodine load using low-concentration contrast agent in high tube output dual-source CT with a standard tube voltage (120kVp) and full-dose iodine load using the same group of adult patients.

METHODS

Fifty-five patients who underwent both low-tube-voltage (70kVp) abdominal CT with a half-dose iodine load and standard-tube-voltage (120kVp) CT with a full-dose iodine load were analyzed. The mean CT values and signal-to-noise ratio (SNR) of the liver, aorta and portal veins were quantitatively assessed. In addition, the contrast enhancement of the abdominal organs and overall image quality were qualitatively evaluated.

RESULTS

The mean CT values and SNR of the liver parenchyma were significantly higher in 70-kVp protocol than in 120-kVp protocol in all 3 phases (p = 0.018 ~  < 0.001). Regarding the qualitative analysis, the overall image quality in the 70-kVp protocol was significantly better than in the 120-kVp protocol in all 3 phases (p < 0.001). In addition, the contrast enhancement scores of the liver parenchyma and hepatic vein in the equilibrium phase were also significantly higher in the 70-kVp protocol than in the 120-kVp protocol (p < 0.001).

CONCLUSION

A low tube voltage (70kVp) in combination with a half-dose iodine load using a low-concentration contrast agent and an iterative reconstruction algorithm in high tube output dual-source CT may improve the contrast enhancement and image quality in multiphasic dynamic CT of the abdomen in patients under 71 kg of body weight.

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

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

The conundrum of contrast-induced acute kidney injury

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

Effect of No Prehydration vs Sodium Bicarbonate Prehydration Prior to Contrast-Enhanced Computed Tomography in the Prevention of Postcontrast Acute Kidney Injury in Adults With Chronic Kidney Disease: The Kompas Randomized Clinical Trial

IMPORTANCE

Prevention of postcontrast acute kidney injury in patients with stage 3 chronic kidney disease (CKD) by means of prehydration has been standard care for years. However, evidence for the need for prehydration in this group is limited.

OBJECTIVE

To assess the renal safety of omitting prophylactic prehydration prior to iodine-based contrast media administration in patients with stage 3 CKD.

DESIGN, SETTING, AND PARTICIPANTS

The Kompas trial was a multicenter, noninferiority, randomized clinical trial conducted at 6 hospitals in the Netherlands in which 523 patients with stage 3 CKD were randomized in a 1:1 ratio to receive no prehydration or prehydration with 250 mL of 1.4% sodium bicarbonate administered in a 1-hour infusion before undergoing elective contrast-enhanced computed tomography from April 2013 through September 2016. Final follow-up was completed in September 2017. Data were analyzed from January 2018 to June 2019.

INTERVENTIONS

In total, 262 patients were allocated to the no prehydration group and 261 were allocated to receive prehydration. Analysis on the primary end point was available in 505 patients (96.6%).

MAIN OUTCOMES AND MEASURES

The primary end point was the mean relative increase in serum creatinine level 2 to 5 days after contrast administration compared with baseline (noninferiority margin of less than 10% increase in serum creatinine level). Secondary outcomes included the incidence of postcontrast acute kidney injury 2 to 5 days after contrast administration, mean relative increase in creatinine level 7 to 14 days after contrast administration, incidences of acute heart failure and renal failure requiring dialysis, and health care costs.

RESULTS

Of 554 patients randomized, 523 were included in the intention-to-treat analysis. The median (interquartile range) age was 74 (67-79) years; 336 (64.2%) were men and 187 (35.8%) were women. The mean (SD) relative increase in creatinine level 2 to 5 days after contrast administration compared with baseline was 3.0% (10.5) in the no prehydration group vs 3.5% (10.3) in the prehydration group (mean difference, 0.5; 95% CI, -1.3 to 2.3; P < .001 for noninferiority). Postcontrast acute kidney injury occurred in 11 patients (2.1%), including 7 of 262 (2.7%) in the no prehydration group and 4 of 261 (1.5%) in the prehydration group, which resulted in a relative risk of 1.7 (95% CI, 0.5-5.9; P = .36). None of the patients required dialysis or developed acute heart failure. Subgroup analyses showed no evidence of statistical interactions between treatment arms and predefined subgroups. Mean hydration costs were €119 (US $143.94) per patient in the prehydration group compared with €0 (US $0) in the no prehydration group (P < .001). Other health care costs were similar.

CONCLUSIONS AND RELEVANCE

Among patients with stage 3 CKD undergoing contrast-enhanced computed tomography, withholding prehydration did not compromise patient safety. The findings of this study support the option of not giving prehydration as a safe and cost-efficient measure.

TRIAL REGISTRATION

Netherlands Trial Register Identifier: NTR3764.

Acute hyperglycemia and contrast-induced nephropathy in patients with non-ST elevation myocardial infarction

Acute hyperglycemia and contrast-induced nephropathy (CIN) are frequently observed in non-ST elevation myocardial infarction (NSTEMI) patients undergoing percutaneous coronary intervention (PCI), and both are associated with an increased mortality rate. We investigated the possible association between acute hyperglycemia and CIN in patients with NSTEMI undergoing PCI.

Materials and methods

We retrospectively enrolled 281(149, 53% men) NSTEMI patients undergoing PCI. For each patient, plasma glucose levels were secreened at hospital admission. Acute hyperglycemia was defined as glucose levels > 198 mg/dl. CIN was defined as an increase in serum creatinine 25% or 0.5 mg/dl from baseline in the first 48-72 hours.

Results

Overall, 44 (15.7%) patients had acute hyperglycemia. Patients with acute hyperglycemia had higher incidence of CIN than those without acute hyperglycemia (29.5 vs 5.1%, P < 0.001). Also, in-hospital mortality, length of hospital stay, major bleeding, requirement of mechanical ventilation and dialysis were observed significantly higher in patients with hyperglycemia. Patients were then reallocated to two groups according to the presence or absence of CIN. Overall, 25 cases (8.9%) of CIN were diagnosed. Diabetes mellitus, weight, age, glucose level and estimated glomerular filtration rate (eGFR) were detected as independent risk factors of CIN. Additionally, admission glucose levels were significantly correlated with creatinine levels after PCI, eGFR and contrast volume/eGFR ratio.

Conclusion

In NSTEMI patients undergoing primary PCI, acute hyperglycemia may be associated with an increased risk for CIN and in-hospital mortality and morbidity.

The role of thiol levels in predicting contrast-induced nephropathy in patients with ST-segment elevation myocardial infarction who underwent primary percutaneous coronary intervention

OBJECTIVE:

Contrast-induced nephropathy (CIN) is a common complication of diagnostic or interventional procedures that may arise from administration of intravascular contrast media. Recent studies have reported the thiol-disulfide ratio as a novel oxidative stress marker. Therefore, we investigated the role of thiol levels in predicting CIN in patients with ST-segment elevation myocardial infarction (STEMI) who had undergone primary percutaneous coronary intervention (PCI).

METHODS:

A total of 302 patients were enrolled in the study. CIN was defined as an increase in serum creatinine concentration ≥0.5 mg/dL compared with the admission value or a >25% relative rise during the first 48–72 hours after the procedure. To evaluate the relationship between thiol levels and CIN, the patients were divided into a CIN group and a non-CIN group.

RESULTS:

CIN occurred in 44 (15%) patients. Native thiol (274.8±84.7 μmol/L vs. 220.8±97.1 μmol/L, p=0.001) and total thiol (305.4±89.7 μmol/L vs. 260.1±102.1 μmol/L, p=0.009) levels were higher in patients within the non-CIN group. Disulfide (15.8±6.6 μmol/L vs. 19.6±8.4 μmol/L, p=0.002) levels, and mean disulfide/total thiol ratios (8.4±3.7 vs. 5.9±3.1, p=0.001) were higher in patients with CIN (+) group. In univariate analysis, the initial native thiol, total thiol, disulfide levels, and disulfide/total thiol ratio were found to have prognostic significance in the development of CIN. In the multivariate regression analysis, only the disulfide/total thiol ratio (OR=1.190; 95% CI: 1.090–1.300; p=0.001) was significantly and independently associated with CIN. The cutoff value of the disulfide/total thiol ratio to predict CIN on admission in patients with STEMI who underwent primary PCI was 7, with a sensitivity of 68.2% and a specificity of 79.8%.

CONCLUSION:

Our results suggest that thiol/disulfide homeostasis could be a good biochemical risk marker for CIN in STEMI patients who underwent primary PCI.

Prevention of contrast-induced nephropathy by adequate hydration combined with isosorbide dinitrate for patients with renal insufficiency and congestive heart failure

BACKGROUND

Adequate hydration remains the mainstay of contrast-induced nephropathy prevention, and nitrates could reduce cardiac preload.

HYPOTHESIS

This study aimed to explore the adequate hydration with nitrates for patients with chronic kidney disease (CKD) and congestive heart failure (CHF) to reduce the risk of contrast-induced nephropathy (CIN) and at the same time avoid the acute heart failure.

METHODS

Three hundred and ninty-four consecutive patients with CKD and CHF undergoing coronary procedures were randomized to either adequate hydration with nitrates (n = 196) or to routine hydration (control group; n = 198). The adequate hydration group received continuous intravenous infusion of isosorbide dinitrate combined with intravenous infusion of isotonic saline at a rate of 1.5 mL/kg/h during perioperative period. The definition of CIN was a 25% or 0.5 mg/dL rise in serum creatinine over baseline. This trial is registered with www.clinicaltrials.gov, number NCT02718521.

RESULTS

Baseline characteristics were well-matched between the two groups. CIN occurred less frequently in adequate hydration group than the control group (12.8% vs 21.2%; P = 0.018). The incidence of acute heart failure did not differ between the two groups (8 [4.08%] vs 6[3.03%]; P = 0.599). Cumulative major adverse events (death, myocardial infarction, stoke, hospitalization for acute heart failure) during the 90-day follow-up were lower in the adequate hydration with nitrates group (P = 0.002).

CONCLUSIONS

Adequate hydration with nitrates can safely and effectively reduce the risk of CIN in patients with CKD and CHF.

Effects of hyperglycaemia and elevated glycosylated haemoglobin on contrast-induced nephropathy after coronary angiography

In patients undergoing percutaneous coronary intervention after acute myocardial infarction, hyperglycaemia on admission is associated with an increased risk of contrast-induced nephropathy (CIN). However, the effects of hyperglycaemia and elevated glycosylated haemoglobin (HbA1c) on CIN have remained to be fully elucidated. Therefore, a prospective cohort study was performed, comprising 258 patients who underwent coronary angiography between May 2017 and November 2017 at Zhongda Hospital affiliated with Southeast University (Nanjing, China). According to the diagnostic criteria for CIN (increase of serum creatinine by >44.2 µmol/l or by 25% within 48-72 h of using contrast agent), the patients were divided into two groups: CIN (45 cases) and non-CIN (213 cases). For all patients, the baseline data, medical history, laboratory parameters, medication history and intraoperative situation were recorded and assessed using single-factor analysis and multiple logistic regression analysis to analyse the risk factors of CIN. The incidence of CIN in the hyperglycaemia group (blood glucose on admission, >11.1 mmol/l) was 25%, compared with 13.8% in the non-hyperglycaemia group (P=0.026). Furthermore, the incidence of CIN in the elevated HbA1c group (HbA1c on admission, upper limit of normal) was 26.1%, compared with 14.3% in the group without elevated HbA1c (P=0.027). Hyperglycaemia was present on hospital admission in 84 of 258 patients (32.6%). The percentage of patients with elevated HbA1c was 26.7%. Age, estimated glomerular filtration rate, pre-operative blood cholesterol, hyperglycaemia on admission and elevated HbA1c were all identified to be associated with CIN. According to the multivariate logistic regression analysis, hyperglycaemia was an independent predictor of CIN (odds ratio, 2.815; 95% confidence interval, 1.042-4.581; P=0.029). In the acute coronary syndrome (ACS) and diabetes subgroups, hyperglycaemia was significantly associated with CIN. In the ACS subgroup, the incidence of CIN was 38.1%. It was indicated that hyperglycaemia is an independent risk factor for CIN, particularly in patients with ACS or diabetes. Trial registration no. ChiCTR-OOC-17011466.

An evaluation of the antioxidant properties of iodinated radiographic contrast media: An in vitro study

This study reveals the antioxidant properties of iodinated radiographic contrast media to be used in diagnostic radiology. Di(phenyl)-(2,4,6-trinitrophenyl) iminoazanium (DPPH), ferric reducing ability of plasma (FRAP), and 2,2'-azino-bis (3-ethylbenzthiazoline-6-sulphonic acid) (ABTS) assays were used for determining in vitro the antioxidant properties of five iodinated radiographic contrast media such as iobitridol (xenetix), iodixanol (visipaque), iohexol (omnipaque), ioxaglate (hexabrix), and isovue (iopamiro). An ascorbic acid and Trolox solution served as a positive control. The absorbance intensity of the colored product was recorded using a spectrophotometer. For DPPH and ABTS assay, the absorbance intensity at 533 and 752 nm, respectively was decreased when compared to control; it indicated an increase in antioxidant activity. For FRAP assay, the absorbance intensity at 593 nm was increased when compared to control; it indicated an increase in antioxidant activity. The results showed that five iodinated radiographic contrast media did not differ in DPPH^• radical-scavenging activity when compared to a corresponding control. The ferric reducing ability of all of these iodinated radiographic contrast media also did not differ when compared to a corresponding control, except for iobitridol at 200 mgI/mL and ioxaglate at 50-200 mgI/mL. All iodinated radiographic contrast media showed ABTS^•+ radical-scavenging activity. This finding suggested that iobitridol, iodixanol, iohexol, ioxaglate, and isovue exhibited weak in vitro antioxidant properties. The antioxidant ability depended on the type of free radical production and the concentration of iodinated radiographic contrast media.

Assessing renal changes after remote ischemic preconditioning (RIPC) of the upper extremity using BOLD imaging at 3T

OBJECTIVE

Acute kidney injury (AKI) is an important risk factor for a number of adverse outcomes including end-stage renal disease and cardiovascular morbidity and mortality. Whilst many clinical situations that can induce AKI are known-e.g. drug toxicity, contrast agent exposure or ischemia during surgery-targeted preventive or therapeutic measures are still lacking. As to renoprotective strategies, remote ischemic preconditioning (RIPC) is one of the most promising novel approaches and has been examined by a number of clinical trials. The aim of this study was to use blood oxygenation level-dependent (BOLD) MRI as a surrogate parameter to assess the effect of RIPC in healthy volunteers.

MATERIALS AND METHODS

In this IRB-approved, prospective study, 40 healthy volunteers were stratified with 20 undergoing an RIPC procedure (i.e. RIPC group) with a transient ischemia of the right arm, and 20 undergoing a sham procedure. Before and after the procedure, both kidneys of all participants were scanned using a 12-echo mGRE sequence for functional BOLD imaging at 3T. For each volunteer, 180 ROIs were placed in the cortex and the medulla of the kidneys. Ultimately, R2* values, which have an inverse correlation with the oxygenation level of tissue, were averaged for the RIPC and control groups.

RESULTS

Following intervention, mean R2* values significantly decreased in the RIPC group in both the cortex (18.6 ± 2.3 vs. 17.5 ± 1.7 Hz; p = 0.0047) and medulla (34 ± 5.2 vs. 32.2 ± 4.2 Hz; p = 0.0001). However, no significant differences were observed in the control group.

CONCLUSION

RIPC can be non-invasively assessed in healthy volunteers using BOLD MRI at 3T, demonstrating a higher oxygen content in kidney tissue. This study presents a first-in-man trial establishing a quantifiable readout of RIPC and its effects on kidney physiology. BOLD measurements may advance clinical trials in further evaluating RIPC for future clinical care.

Hypotonic contrast media is more toxic than isotonic contrast media on endothelial cells in vivo and in vitro

The aim of the current study was to investigate the cytotoxic effects of hypotonic (iopamidol) and isotonic (iodixanol) contract media (CMs) in vitro and in vivo. A total of 60 Wistar rats were included and were randomly divided into three groups (20 rats per group). Iodixanol (4 g iodine/kg), iopamidol (4 g iodine/kg) or equal volume of normal saline was injected via tail vein. HUVEC and H5V cell viability was determined by Cell Counting Kit‑8 agents. Western blotting was performed to detect ATP‑binding cassette subfamily G member 1 (ABCG1) expression. For histological analysis, hematoxylin and eosin staining was performed. Plasma endothelin, von Willebrand factor, tissue type plasminogen activator, plasminogen activator inhibitor, D‑Dimer, fibrinogen, anti‑thrombin III, plasminogen and nitric oxide synthase (NOS) were measured by using ELISA. Both iopamidol and iodixanol treatments deceased cell viability and increased apoptosis of HUVEC and H5V cells, along with downregulated NOS and ABCG1. The injection of iopamidol or iodixanol into rats changed the endothelium‑related plasma levels of biomarkers, including endothelin, von Willebrand factor, tissue type plasminogen activator, plasminogen activator inhibitor, D‑Dimer, fibrinogen and anti‑thrombin III. However, endothelia isolated from rat abdominal aorta in the iodixanol group retained their normal structure, whereas endothelial structure in the iopamidol group was injured and disrupted. The findings in the present study suggested that both hypotonic and isotonic CMs may lead to endothelial dysfunction and thrombin and fibrinolytic system disorder. However, hypotonic CMs may be more toxic than isotonic CMs. Therefore, additional cautions should be taken when selecting hypotonic CMs and their dosages during cardioangiography.

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.

Contrast-Induced Acute Kidney Injury: An Update

Contrast-induced acute kidney injury (CI-AKI) is defined as an abrupt deterioration in renal function associated with the administration of iodinated contrast media. This type of acute kidney injury is frequently encountered as a complication of percutaneous coronary intervention (PCI) and is associated with adverse short- and long-term outcomes including mainly mortality, cardiovascular morbidity and prolongation of hospitalization. The incidence of CI-AKI after PCI ranges from 2 to 20 % according to baseline kidney function. It may also range according to the clinical setting, being higher after emergency PCI. The primary manifestation is a small decline in kidney function, occurring 1 to 3 days after the procedure. Kidney function usually returns to preexisting levels within 7 days. Incidence of acute renal failure requiring dialysis following PCI is rare (<1 %). The present article aims to review up-to-date published data concerning diagnosis, definition, epidemiology and prognosis of this novel in-hospital epidemic.

Prevention of acute kidney injury in Intensive Care Units

Acute kidney injury (AKI) is a growing concern in Intensive Care Units. The advanced age of our patients, with the increase in associated morbidity and the complexity of the treatments provided favor the development of AKI. Since no effective treatment for AKI is available, all efforts are aimed at prevention and early detection of the disorder in order to establish secondary preventive measures to impede AKI progression. In critical patients, the most frequent causes are sepsis and situations that result in renal hypoperfusion; preventive measures are therefore directed at securing hydration and correct hemodynamics through fluid perfusion and the use of inotropic or vasoactive drugs, according to the underlying disease condition. Apart from these circumstances, a number of situations could lead to AKI, related to the administration of nephrotoxic drugs, intra-tubular deposits, the administration of iodinated contrast media, liver failure and major surgery (mainly heart surgery). In these cases, in addition to hydration, there are other specific preventive measures adapted to each condition.

Is there any role of epithelial to mesenchymal transition in the pathogenesis of contrast nephropathy?

AIM

Contrast medium-induced nephropathy is one of the major complications of intravenous contrast medium use. But its pathogenesis is unclear. Epithelial mesenchymal transition (EMT) is defined as the transformation of the primer epithelial cells to mesenchymal cells. EMT in tubular cells might cause tubulointerstitial damage. In this study, we investigated whether or not EMT has a role in radiocontrast-induced nephropathy. Radiocontrast medium might be triggering reversible EMT via serum and glucocorticoid-regulated kinase 1 (SGK 1). We investigated the effect of different concentrations of the contrast agent iopromide on human proximal tubule cell (HK-2) culture by measuring the level of SGK1, snail family zinc finger 1 (SNAIL1), connective tissue growth factor (CTGF), and collagen type I alpha 1 (COL1A1).

METHODS

We conducted a scratch assay and qPCR. HK-2 cells were cultured in the petri dishes/flasks and starved with serum-free medium. The 40, 20, and 10 mg/mL doses of iopromide were administrated to cells. The scratches were photographed immediately and again at the 20th hour. The levels of gene expression of SGK1, SNAIL1, CTGF, and COL1A1 were measured using the real-time qPCR system at the end of the 24th hour.

RESULTS

Iopromide caused the breaking of intercellular connections, the disappearance of the cobblestone appearance of cells, and the migration of cells at the 20th hour in the scratch assay. It also increased the expression of SGK1, SNAIL1, CTGF, and COL1A1 genes.

CONCLUSION

Our study concluded that certain important markers of EMT increase in different concentrations of the contrast agent. High osmolality might trigger EMT. The relationship between contrast agent and EMT has not been defined before. Further in vivo and in vitro studies are required.

Impact of post-procedural hyperglycemia on acute kidney injury after transcatheter aortic valve implantation

BACKGROUND

Post-operative hyperglycemia, in individuals with and without diabetes, has been identified as a predictor of acute kidney injury (AKI) in patients following cardiac surgery. Whether or not this is also true for patients undergoing transcatheter aortic valve implantation (TAVI) is unknown.

OBJECTIVES

To evaluate whether post-procedural glucose levels are associated with AKI after TAVI.

METHODS AND RESULTS

A total of 422 consecutive patients undergoing transfemoral TAVI were included in the analysis. For each patient, plasma glucose levels were assessed at hospital admission, 4h after the procedure and daily during hospitalization. Post-procedural hyperglycemia was defined as 2 consecutive blood glucose readings ≥150mg/dL in the 72-hour period following TAVI. AKI was defined according to the VARC consensus report regarding standardized endpoint definitions. Overall, 137 (32.5%) patients developed post-procedural hyperglycemia and 138 (33%) patients developed AKI. Hyperglycemia was associated with a 2-fold higher incidence of AKI than in patients without hyperglycemia (48% vs. 25%, p<0.001). In-hospital mortality was higher in patients with hyperglycemia than in those without hyperglycemia (9.6% vs. 1.8%, p<0.001). In-hospital mortality rate was also higher in patients who developed AKI (12.7% vs. 2.7%, p<0.001). Patients with acute hyperglycemia that developed AKI had the highest in-hospital and long-term mortality rate (15% and 38%). Post-procedural hyperglycemia was an independent predictor of AKI.

CONCLUSIONS

Post-procedural hyperglycemia is associated with a higher incidence of AKI and mortality after TAVI. Randomized controlled trials are needed to determine whether meticulous post-procedural glycemic control following TAVI impacts upon clinical outcomes.

Renal Protective Effect of Probucol in Rats with Contrast-Induced Nephropathy and its Underlying Mechanism

Background

Contrast-induced nephropathy (CIN) refers to acute renal damage that occurs after the use of contrast agents. This study investigated the renal protective effect of probucol in a rat model of contrast-induced nephropathy and the mechanism of its effect.

Material/Methods

Twenty-eight Wistar rats were randomly divided into the control group, model group, N-acetylcysteine(NAC) group, and probucol group. We used a rat model of iopromide-induced CIN. One day prior to modeling, the rats received gavage. At 24 h after the modeling, blood biochemistry and urine protein were assessed. Malondialdehyde (MDA) and superoxide dismutase (SOD) were measured in renal tissue. Kidney sections were created for histopathological examination.

Results

The model group of rats showed significantly elevated levels of blood creatinine, urea nitrogen, 24-h urine protein, histopathological scores, and parameters of oxidative stress (P<0.05). Both the NAC and probucol groups demonstrated significantly lower Scr, BUN, and urine protein levels compared to the model group (P<0.05), with no significant difference between these 2 groups. The NAC group and the probucol group had significantly lower MDA and higher SOD than the model group at 24 h after modeling (P<0.05). The 8-OHdG-positive tubule of the probucol group and NAC group were significantly lower than those of the model group (p=0.046, P=0.0008), with significant difference between these 2 groups (P=0.024).

Conclusions

Probucol can effectively reduce kidney damage caused by contrast agent. The underlying mechanism may be that probucol accelerates the recovery of renal function and renal pathology by reducing local renal oxidative stress.

Predictive Value of Gamma-Glutamyl Transferase Levels for Contrast-Induced Nephropathy in Patients With ST-Segment Elevation Myocardial Infarction Who Underwent Primary Percutaneous Coronary Intervention

Contrast-induced nephropathy (CIN) after primary percutaneous coronary intervention (PPCI) is associated with adverse short- and long-term outcomes. The aim of this study was to evaluate the predictive value of gamma-glutamyl transferase (GGT) for risk of CIN in patients with ST-segment elevation myocardial infarction who underwent PPCI. A total of 473 patients were enrolled in the study. A relative increase in serum creatinine ≥25%, or an absolute increase ≥0.5 mg/dl, from the baseline within 72 hours of contrast exposure was defined as CIN. Patients were divided into 3 groups according to GGT tertiles (tertile 1, GGT <19 U/L; tertile 2, GGT 19 to 33 U/L; and tertile 3, GGT >33 U/L) on admission. Demographics, clinical risk factors, laboratory parameters, CIN incidence, and other inhospital clinical outcomes were compared among GGT tertiles. CIN incidence was significantly higher in tertile 3 (29%) compared with tertiles 1 (11%) and 2 (11%, p <0.001). Inhospital death incidence was significantly increased across tertiles (from tertile 1 to tertiles 2 and 3, 1%, 4%, and 5%, respectively, p <0.05). In receiver operating characteristic analysis, a threshold value of GGT >26.5 U/L had 70% sensitivity and 60% specificity for CIN. After including variables found significant in univariate analysis, the presence of diabetes mellitus (odds ratio [OR] 1.71, 95% confidence interval [CI] 1.22 to 2.31, p <0.001), C-reactive protein (for each 1 mg/L increase; OR 1.01, 95% CI 1.00 to 1.02, p = 0.007), contrast volume (for each 1-ml increase; OR 1.01, 95% CI 1.00 to 1.02, p = 0.012), and GGT >26.5 U/L (OR 2.59, 95% CI 1.48 to 4.53, p <0.001) were found as independent associates of CIN in multivariate regression analysis. Each 1 U/L increase in GGT was also associated with CIN risk (OR 1.04, 95% CI 1.03 to 1.06, p <0.001). In conclusion, GGT on admission was a significant and independent predictor of CIN after PPCI in patients with ST-segment elevation myocardial infarction.

Use of cystatin C and serum creatinine for the diagnosis of contrast-induced nephropathy in patients undergoing contrast-enhanced computed tomography at an oncology centre

OBJECTIVE

Our aim was to assess renal function using as laboratory measurements serum creatinine and cystatin C concentrations before and after administration of low-osmolarity (nonionic) iodinated contrast medium in patients with cancer undergoing computed tomography (CT).

METHODS

This prospective study included 400 oncologic outpatients. Serum creatinine and cystatin C concentrations were measured before and 72 h after contrast administration. Glomerular filtration rates (GFRs) were estimated using serum creatinine-based [Modification of Diet in Renal Disease (MDRD) and Cockroft-Gault and cystatin C based (Larsson) equations. Exploratory data analysis was performed. The nonparametric Wilcoxon test was used to compare pre and post contrast of test results and estimated clearance. The confidence interval used in the analysis was 95%.

RESULTS

Compared with the pre-contrast values, the mean serum creatinine concentration was significantly higher and average GFRs estimated using MDRD and Cockcroft-Gault equations were significantly lower after the administration of contrast (p <0.001). It was also observed a significant increase after contrast in the concentration of Cystatin C (p = 0.015). In addition, a decrease in GFR estimated using the average Larsson (p = 0.021) was observed between time points. However, none of the patients presented clinically significant nephropathy.

CONCLUSIONS

Assessment using serum creatinine and cystatin C concentrations showed changes in renal function among patients with cancer undergoing contrast-enhanced CT examination in this study. No significant renal damage related to the use of low-osmolarity iodinated contrast medium of the type and dosage employed in this study was observed. This contrast medium is thus safe for use in patients with cancer.

Trimetazidine Decreases Risk of Contrast-Induced Nephropathy in Patients With Chronic Kidney Disease

Objectives:

We sought to synthesize and analyze the available data from randomized controlled trials (RCTs) for trimetazidine (TMZ) in the prevention of contrast-induced nephropathy (CIN).

Background:

Contrast-induced nephropathy after coronary angiography is associated with poor outcomes. Trimetazidine is an anti-ischemic drug that might reduce incidence of CIN, but current data are inconclusive.

Methods:

We searched MEDLINE/PubMed, EMBASE, Scopus, Cochrane Library, Web of Science, and ScienceDirect electronic databases for RCTs comparing intravenous hydration with normal saline (NS) and/or N-acetyl cysteine (NAC) versus TMZ plus NS ± NAC for prevention of CIN. We used RevMan 5.2 for statistical analysis with the fixed effects model.

Results:

Of the 808 studies, 3 RCTs met criteria with 290 patients in the TMZ plus NS ± NAC group and 292 patients in the NS ± NAC group. The mean age of patients was 59.5 years, and baseline serum creatinine ranged from 1.3 to 2 mg/dL. Trimetazidine significantly reduced the incidence of CIN by 11% (risk difference 0.11; 95% confidence interval, 0.16-0.06; P < .01). There was no significant heterogeneity between the studies (I2 statistic = 0). The number needed to treat to prevent 1 episode of CIN was 9.

Conclusions:

The addition of TMZ to NS ± NAC significantly decreased the incidence of CIN in patients undergoing coronary angiography. In conclusion, TMZ could be considered as a potential tool for prevention of CIN in patients with renal dysfunction.

LDL cholesterol as a novel risk factor for contrast-induced acute kidney injury in patients undergoing percutaneous coronary intervention

BACKGROUND

Low density lipoprotein cholesterol (LDL-C) is associated with endothelial dysfunction, inflammation and increased vasoconstriction, which are involved in the development of contrast-induced acute kidney injury (CI-AKI). However, whether LDL-C is an independent risk factor of CI-AKI in patients undergoing percutaneous coronary intervention (PCI) is unknown.

METHODS

We prospectively enrolled 3236 consecutive patients undergoing PCI between January 2010 and September 2012. Multivariate logistic regression analysis was used to determine whether LDL-C is an independent risk factor of CI-AKI. CI-AKI was defined as an absolute increase in serum creatinine of ≥ 0.5 mg/dL or ≥ 25% over the baseline value within 48-72 h after contrast exposure.

RESULTS

CI-AKI was observed in 338 patients (10.4%). Patients with CI-AKI had a significantly higher rate of in hospital mortality (4.4% vs. 0.5%, p < 0.001), and significantly higher rates of other in hospital complications compared with those without CI-AKI. The LDL-C quartiles were as follows: Q1 (<2.04 mmol/L), Q2 (2.04-2.61 mmol/L), Q3 (2.61-3.21 mmol/L) and Q4 (>3.21 mmol/L). Patients with high baseline LDL-C levels were more likely to develop CI-AKI and composite end points including all-cause mortality, renal replacement therapy, non-fatal myocardial infarction, acute heart failure, target vessel revascularization or cerebrovascular accident during the observation period of hospitalization (8.9%, 9.9%, 10.5%, 12.6%, p = 0.001, and 5.0%, 5.2%, 6.1%, 8.1%, respectively; p = 0.007). Univariate logistic analysis showed that LDL-C levels (increment 1 mmol/L) were significantly associated with CI-AKI (odds ratio = 1.25, 95% confidence interval (CI), 1.11-1.39, p < 0.001). Furthermore, LDL-C remained a significant risk factor of CI-AKI (odds ratio = 1.23, 95% CI, 1.04-1.45, p = 0.014), even after adjusting for potential confounding risk factors.

CONCLUSIONS

Measurement of plasma LDL-C concentrations in patients undergoing PCI may be helpful to identify those who are at risk of CI-AKI and poor in hospital outcomes.

Acute kidney injury after primary angioplasty: effect of different hydration treatments

AIMS

We evaluated the effect of different dose hydration protocols, with normal saline or bicarbonate, on the incidence of contrast-induced acute kidney injury (CI-AKI) in patients with ST-elevation myocardial infarction (STEMI) treated with primary percutaneous coronary intervention (PPCI).

METHODS

We considered 592 STEMI patients treated with PPCI in 5 Italian centers. Patients were randomized to receive standard or high-dose infusions of normal saline or sodium bicarbonate started immediately before contrast medium administration and continued for the following 12 h.

RESULTS

The cumulative incidence of CI-AKI was 18.1% without any difference among treatment groups. Shock, age, ejection fraction 35% or less, and basal serum creatinine were significantly associated with an increased risk of CI-AKI. Follow-up at 12 months was complete in 573 patients. Overall, 25 out of 573 patients died (4.3%). We observed higher short-term mortality rates in patients receiving high-volume hydration. Otherwise, only age, shock and CI-AKI were significantly associated with 1-year mortality.

CONCLUSION

In patients with STEMI undergoing PPCI, high-volume hydration with normal saline or sodium bicarbonate administrated at the time of contrast media administration was not associated with any significant advantage in terms of CI-AKI prevention.

Statins for the Prevention of Contrast-Induced Nephropathy After Coronary Angiography/Percutaneous Interventions: A Meta-analysis of Randomized Controlled Trials

BACKGROUND

Statins have been demonstrated to prevent the development of contrast-induced nephropathy (CIN). Nevertheless, clinical research has indicated conflicting results. We performed a meta-analysis of randomized controlled trials (RCTs) to evaluate the protective effects of statins on CIN and the requirement of renal replacement therapy (RRT) in patients undergoing coronary angiography/percutaneous interventions.

METHODS

PubMed, MEDLINE, Web of Science, EMBASE, ClinicalTrials.gov, and the Cochrane Central RCTs were searched for RCTs from inception to February 2014 to compare statins with placebo treatment for preventing CIN in patients undergoing coronary angiography/percutaneous interventions.

RESULTS

Nine RCTs were identified and analyzed in a total of 5143 patients involving 2560 patients with statin pretreatment and 2583 patients as control. Patients who received statin therapy had a 53% lower risk of CIN with different definitions (within 48 or 72 hours) compared to the control group based on a fixed effect model (risk ratio = 0.47, 95% confidence interval = 0.37-0.60, P < .0001) and were less likely to require RRT based on Peto fixed effect. Subgroup analysis showed that statin pretreatment could decrease the incidence of CIN in patients with preexisting renal dysfunction or diabetes mellitus. In addition, patients on rosuvastatin had a similar reduced incidence of CIN compared to patients on atorvastatin.

CONCLUSION

This updated meta-analysis demonstrated that preprocedural statin treatment could reduce the risk of CIN and the need for RRT in patients undergoing coronary angiography/percutaneous interventions. Moreover, statin therapy would be helpful in reducing the incidence of CIN in high-risk patients with preexisting renal dysfunction or diabetes mellitus. Additionally, rosuvastatin and atorvastatin had similar efficacies in preventing CIN development.

Oxidative Stress and Paraoxonase 1 Activity Predict Contrast-Induced Nephropathy in Patients With ST-Segment Elevation Myocardial Infarction Undergoing Primary Percutaneous Coronary Intervention

Reactive oxygen species have been implicated in the pathogenesis of contrast-induced nephropathy (CIN). We investigated the relationship between CIN with paraoxonase 1 (PON-1) activity and oxidative stress markers (total antioxidant status [TAS], total oxidant status [TOS], and oxidative stress index [OSI]) in patients with anterior ST-segment elevation myocardial infarction (STEMI) undergoing primary percutaneous coronary intervention; 289 consecutive patients with STEMI were prospectively included. The patients were divided into 2 groups: CIN (n = 69) and non-CIN (n = 220). Activity of PON-1 and TAS levels were significantly lower and OSI and TOS levels were significantly higher in patients with CIN compared to the non-CIN group ( P < .05, for all). On multivariate logistic regression analysis, PON-1 activity and OSI as well as the amount of contrast medium and diabetes were independent predictors for CIN in patients with anterior STEMI. Activity of PON-1 and oxidative stress may play a role in the pathogenesis of CIN.

Association between Glycosylated Haemoglobin Level and Contrast-Induced Acute Kidney Injury in Patients with Type 2 Diabetes Mellitus

BACKGROUND

There are several reports suggesting that admission hyperglycaemia increases the risk of contrast-induced acute kidney injury (CI-AKI). However, it is not clear whether there has been an association between long-standing poor glycaemic control and the incidence of CI-AKI. The purpose of this study was to examine the impact of poor glycaemic control or elevated glycosylated haemoglobin (HbA1c) on the incidence of CI-AKI in patients with type 2 diabetes mellitus (T2DM).

METHODS

The present study prospectively enrolled 133 patients with T2DM undergoing elective coronary angiography (CAG) and/or intervention. All patients had an estimated glomerular filtration rate (eGFR) of ≥60 ml/min/1.73 m(2). Patients were divided into two groups: those with an optimal HbA1c (<7%) and those with an elevated HbA1c (≥7%). All had similar baseline characteristics and were hydrated appropriately. The outcome was assessed by the incidence of CI-AKI.

RESULTS

CI-AKI occurred in 2 of 41 patients (4.9%) with optimal HbA1c levels and 5 of 92 patients (5.4%) with elevated HbA1c levels (p = 0.89). The cutoff point of HbA1c was set at 6.5%, but no statistically significant difference between the two groups was observed [1 of 24 patients (4.1%) vs. 6 of 109 patients (5.5%), p = 0.79]. However, despite a high variability in the incidence of CI-AKI, there was no statistically significant difference between the two groups when varying CI-AKI definitions were considered.

CONCLUSION

An elevated HbA1c level is not associated with a higher incidence of CI-AKI compared to optimal HbA1c levels in patients with T2DM (patients with an eGFR of ≥60 ml/min/1.73 m(2)) undergoing CAG and/or intervention.

Is contrast medium osmolality a causal factor for contrast-induced nephropathy?

The exact pathophysiology of contrast-induced nephropathy (CIN) is not fully clarified, yet the osmotic characteristics of contrast media (CM) have been a significant focus in many investigations of CIN. Osmotic effects of CM specific to the kidney include transient decreases in blood flow, filtration fraction, and glomerular filtration rate. Potentially significant secondary effects include an osmotically induced diuresis with a concomitant dehydrating effect. Clinical experiences that have compared the occurrence of CIN between the various classes of CM based on osmolality have suggested a much less than anticipated advantage, if any, with a lower osmolality. Recent animal experiments actually suggest that induction of a mild osmotic diuresis in association with iso-osmolar agents tends to offset potentially deleterious renal effects of high viscosity-mediated intratubular CM stagnation.

Effect of renin-angiotensin-system blockers on contrast-medium-induced acute kidney injury after coronary angiography

BACKGROUND/AIMS

With the increasing incidence of cardiovascular disease, angiocardiography using contrast-enhancing media has become an essential diagnostic and therapeutic tool, despite the risk of contrast-medium-induced acute kidney injury (CIAKI). CIAKI may be exacerbated by renin-angiotensin-system (RAS) blockers, which are also used in a variety of cardiovascular disorders. This study evaluated the effects of RAS blockade on CIAKI after coronary angiography.

METHODS

Patients who underwent coronary angiography in our hospital between May 2009 and July 2011 were reviewed. Serum creatinine levels before and after coronary angiography were recorded. CIAKI was diagnosed according to an increase in serum creatinine > 0.5 mg/dL or 25% above baseline.

RESULTS

A total of 1,472 subjects were included in this study. Patients taking RAS blockers were older, had a higher baseline creatinine level, lower estimated glomerular filtration rate (eGFR), and had received a greater volume of contrast medium. After propensity score matching, no difference was observed between the RAS (+) and RAS (.) groups. Multiple logistic regression identified RAS blockade, age, severe heart failure, contrast volume used, hemoglobin level, and eGFR as predictors of CIAKI. Multiple logistic regression after propensity matching showed that RAS blockade was associated with CIAKI (odds ratio, 1.552; p = 0.026).

CONCLUSIONS

This study showed that the incidence of CIAKI was increased in patients treated with RAS blockers.

Use of alpha-lipoic acid in prevention of contrast-induced nephropathy in diabetic patients

In this prospective study, we aimed to determine the protective antioxidant role of alpha-lipoic acid (ALA) on development of contrast-induced nephropathy (CIN) in diabetic patients undergoing coronary angiography. Seventy-eight diabetic patients undergoing coronary angiography were included. Thirty-nine patients were randomized to control group and 39 patients to ALA group. Both groups were hydrated on the day of angiography, and the ALA group had also received three doses of "Thioctacid 600 mg HR, MEDA Manufacturing GmbH" in pill form. Serum creatinine clearance, cystatin C, and urinary neutrophil gelatinase-associated lipocalin (NGAL) were studied before and after angiography. We defined CIN as either ≥25% or ≥0.5 mg/dL increase in serum creatinine at 48th hour after angiography. Baseline clinical characteristics were similar in both groups. Mehran risk score and creatinine clearance were comparable in control and therapy groups (5.59 ± 1.96 vs. 5.49 ± 1.73, p = 0.54 and 89 ± 21 vs. 96 ± 24, p = 0.13, respectively). The volumes of contrast media (median values of 80 mL vs. 75 mL) and hydration with saline (2862 ± 447 mL vs. 2637 ± 592 mL) were also similar (p > 0.05). The incidence of CIN was the same (8%) in both the groups. Alterations in serum creatinine, cystatin C, and urinary NGAL levels before and after the procedure were comparable between the ALA and control groups (group p-values were >0.05 in two-way repeated measures analysis of variance). We presented for the first time that ALA therapy added to hydration does not decrease the risk of CIN development in diabetic patients undergoing coronary angiography.

Gene polymorphisms of interleukin-10 and tumor necrosis factor-α are associated with contrast-induced nephropathy

BACKGROUND/AIMS

Contrast-induced nephropathy (CIN) is the third most common cause of hospital-acquired acute renal failure. However, the pathogenesis of CIN remains unclear. This study evaluated the role of anti-inflammatory cytokine interleukin-10 (IL-10) and pro-inflammatory cytokine tumor necrosis factor-α (TNF-α) gene polymorphisms as CIN susceptibility markers after percutaneous coronary intervention (PCI).

METHODS

Four IL-10 tag SNPs (rs1554286, rs3021094, rs3790622, rs1800896) and three TNF-α tag SNPs (rs1799964, rs1800630, rs1800629) were analyzed by MALDI-TOF mass spectrometry in 53 CIN patients and 455 control subjects. Serum IL-10 and TNF-α were detected using ELISA.

RESULTS

When compared to controls, the CIN patients showed increased frequencies of CC (rs1554286) and AG+GG (rs1800896) genotypes in IL-10 and GA+AA (rs1800629) genotype in TNF-α (OR = 2.24 (1.13-4.44), p = 0.018; OR = 2.61 (1.30-5.26), p = 0.005, and OR = 2.11 (1.08-4.09), p = 0.025, respectively). Baseline serum IL-10 levels in CIN patients were significantly lower (1.02 ± 1.14 vs. 2.78 ± 4.73 pg/ml, p = 0.008). Patients with CIN had a higher rate of decline in renal function than those without CIN (0.89 ± 1.67 vs. 0.30 ± 0.95 ml/min/1.73 m(2) per month, p = 0.002). Significantly higher rates of decline in creatinine clearance were noted in patients with TNF-α (rs1800629) GA+AA than GG genotype (0.88 ± 1.83 vs. 0.36 ± 0.70, p = 0.03), and with IL-10 (rs1800896) AG+GG than AA genotype (1.28 ± 2.14 vs. 0.33 ± 0.90, p < 0.001).

CONCLUSIONS

Gene polymorphisms of IL-10 and TNF-α are associated with CIN risk and long-term renal outcome after PCI. More prospective studies are needed to confirm our results.

Renal management in the critically ill patient

Acute kidney injury is common in the hospital setting and morbidity and mortality outcomes depend on early recognition and early intervention. Identifying patients at risk of acute kidney injury is critical in prevention, early identification, and appropriate treatment.

Effects of the radiocontrast agent iodixanol on endothelial cell morphology and function

Iodinated radiocontrast media (RCM) are usually well tolerated, but their large and increasing use renders their toxicity a relevant problem, especially in high risk patients. The aim of the study was to investigate the possible toxic or activating effects of iodixanol on endothelial cells (EC) and the putative in vitro protective action of N-acetylcysteine and rosuvastatin. Morphology, oxidative status, redistribution of heat-shock protein 60 and secretion of proinflammatory products were studied in cultured human EC through confocal microscopy, immunofluorescence and immuno-enzymatic methods. EC reacted to iodixanol with shrinking and bulging, increase in intracellular oxidation and translocation of Heat Shock Protein 60 to the cell membrane. The secretion of proinflammatory products was strongly stimulated by sequential incubation of EC with iodixanol and TNFα (p<0.00001 for all tested molecules, namely TNFα, IL-8, sVCAM-1, MCP-1, and IL-6). N-acetylcysteine prevented morphologic and oxidative derangements, and significantly reduced proinflammatory product secretion (P range<0.0001 to<0.00001 for TNFα, VCAM-1, MCP-1, and IL-6); rosuvastatin inhibited morphology and oxidative modifications only. Our data help clarifying the mechanisms of early and late toxicity of RCM and support the use of anti-oxidant and anti-inflammatory agents for optimization of radiological procedures in high risk patients.

Parstatin prevents renal injury following ischemia/reperfusion and radiocontrast administration

BACKGROUND/AIMS

Parstatin is a 41-mer peptide formed by proteolytic cleavage on activation of the protease-activated receptor 1. Parstatin was recently found to be cardioprotective against myocardial ischemia/reperfusion (IR) injury. In the present study, it was hypothesized that parstatin would protect the kidneys in acute renal failure.

METHODS

We investigated the effects of parstatin on the renal dysfunction and injury caused either by renal IR injury or contrast-induced nephropathy (CIN) in two animal models. Renal IR injury was induced in rats by bilateral occlusion of renal arteries and veins for 45 min followed by 4 h of reperfusion, while CIN was induced in rabbits by intravenous injection of the radiocontrast medium Iopromide.

RESULTS

Treatment with parstatin 15 min before or immediately after renal ischemia attenuated the resulting renal dysfunction as demonstrated by the improved biochemical indicators (serum creatinine and fractional excretion of Na(+)) and scintigraphic analysis. The effect was dose depended and provided evidence for a more prominent protection of tubular than glomerulal function. Histopathological examination of the kidneys revealed severe renal damage, which was significantly suppressed by the parstatin. Similarly, administration of a single dose of parstatin before the induction of CIN significantly protected against the resulting renal dysfunction and histologically evidenced renal tubular injury.

CONCLUSION

These results suggest that parstatin is able to act as nephroprotective agent and may be useful in enhancing the tolerance of the kidney against renal injury associated with clinical conditions of acute renal failure. Further investigation on the mechanism underlying the nephroprotective properties of parstatin is deemed necessary.