Contrast-induced nephropathy in percutaneous coronary interventions: pathogenesis, risk factors, outcome, prevention and treatment

Comparing the clinical utility of single-shot, readout-segmented and zoomit echo-planar imaging in diffusion-weighted imaging of the kidney at 3 T

We compared the clinical utility of single-shot echo-planar imaging (SS-EPI) using different breathing schemes, readout-segmented EPI and zoomit EPI in the repeatability of apparent diffusion coefficient (ADC) measurements, cortico-medullary contrast to noise ratio (c-mCNR) and image quality. In this institutional review board-approved prospective study, some common clinically applicable diffusion-weighted imaging (b = 50, 400, 800 s/mm²) of kidney on 3.0 T MRI were performed on 22 volunteers using SS-EPI with breath-hold diffusion-weighted imaging (BH-DWI), free-breathing (FB-DWI), navigator-triggered (NT-DWI) and respiratory-triggered (RT-DWI), readout-segmented DWI (RS-DWI), and Zoomit DWI (Z-DWI). ADC and c-mCNR were measured in 12 anatomic locations (the upper, middle, and lower pole of the renal cortex and medulla), and image quality was assessed on these DWI sequences. A DWI with the optimal clinical utility was decided by systematically assessing the ADC repeatability, c-mCNR and image quality among the DWIs. For ADC measurements, Z-DWI had an excellent intra-observer agreement (intra-class correlation coefficients (ICCs): 0.876–0.944) and good inter-observer agreement (inter-class ICCs: 0.798–0.856) in six DWI sequences. Z-DWI had the highest ADC repeatability in most of the 12 anatomic locations of the kidneys (mean ADC absolute difference: 0.070–0.111 × 10⁻³ mm²/s, limit of agreement: 0.031–0.056 × 10⁻³ mm²/s). In all DWIs, Z-DWI yielded a slightly higher c-mCNR than other DWIs in most representative locations (P > 0.05), which was significantly higher than BH-DWI and FB-DWI in the middle pole of both kidneys and the upper pole of the left kidney (P < 0.05). In addition, Z-DWI yielded image quality that was similar to RT-DWI and NT-DWI (P > 0.05) and superior to BH-DWI, FB-DWI and RS-DWI (P < 0.05). Our results suggest that Z-DWI provides the highest ADC reproducibility, better c-mCNR and good image quality on 3.0 T MRI, making it the recommended sequence for clinical DWI of the kidney.

Effect of Calcium Dobesilate in Preventing Contrast-Induced Nephropathy in Patients with Diabetes and Chronic Kidney Disease

OBJECTIVES

This study assessed the protective effect of calcium dobesilate against contrast-induced nephropathy (CIN) after coronary angiography (CAG) or percutaneous coronary intervention (PCI) in patients with diabetes and chronic kidney disease (CKD).

METHODS

A total of 130 patients with diabetes and CKD estimated glomerular filtration rate: 30-90 mL/min/1.73m2 were enrolled and included in the analysis. They were divided into experimental (n=65) and control groups (n=65). Patients in the experimental group were administered oral calcium dobesilate (500 mg) three times daily for 2 days before and 3 days after the procedure. The serum creatinine (SCr), cystatin C (Cys C), and neutrophil gelatinase-associated lipocalin (NGAL) levels were measured before and after the procedure.

RESULTS

The mean SCr level at 24h after the procedure was found to be significantly lower in the experimental group than in the control group (79.1±19.6 μmol/L vs. 87.0±19.3 μmol/L, p=0.023). However, the Cys C and NGAL levels were not significantly different between the two groups at all measurement time points (all p>0.05). The incidence of CIN defined by the SCr level was significantly lower in the experimental group than in the control group (3 [4.6%] vs. 13 [20.0%], p=0.017). However, the incidence of CIN defined by the Cys C level was not statistically different between the two groups (7 [10.8%] vs. 7 [10.8%], p=1.000).

CONCLUSIONS

This study revealed that calcium dobesilate has no preventive effect against CIN in patients with diabetes and CKD.

MicroRNA as an early diagnostic biomarker for contrast-induced acute kidney injury

Contrast-induced acute kidney injury (CI-AKI) is a common clinical complication and an important cause of increased mortality, prolonged hospitalization, and increased medical costs. For taking effective interventions in CI-AKI, early diagnosis and active prevention are of key importance. Currently, early CI-AKI detection depends on serum creatinine (Scr) levels, which lags behind the actual time of renal injury and seriously affects early diagnosis and interventions. MicroRNA (miRNA) has been found to be a useful biomarker in early CI-AKI diagnosis. Several studies have reported on tissue and time-specific miRNAs in AKI as effective diagnostic biomarkers and potential therapeutic targets, but there are only a few studies on miRNA in CI-AKI. However, these studies are preliminary exploratory investigations on changes in miRNA expression in CI-AKI, and whether these specific miRNAs can be used as biomarkers for early CI-AKI diagnosis and as clinical therapeutic targets requires systematic and in-depth studies. Therefore, more sensitive and specific miRNAs of CI-AKI could be discovered, providing newer options and development directions for early diagnosis and intervention in clinical CI-AKI practice. This review evaluates the research progress on specific miRNAs in the early diagnosis of CI-AKI with an aim of providing basic data for the clinical application of these molecular markers in CI-AKI.

Diagnostic performance of coronary angiography utilizing intraprocedural 320-row computed tomography with minimal contrast medium

Recently developed coronary angiography with intraprocedural 320-row computed tomography can be performed in a catheterization laboratory (XACT) by injecting contrast medium from a place close to the coronary arteries, thereby requiring a minimal amount of contrast medium. However, its clinical application has not yet been established. This study aimed to evaluate the diagnostic accuracy of XACT angiography with a minimal volume of contrast medium in patients with suspected coronary artery disease (CAD). A total of 167 coronary segments were analyzed in 14 patients (9 males, median age 70 years) with suspected CAD by XACT angiography with 7.5 ml of contrast medium and invasive coronary angiography (ICA) with standard techniques. The segmental-based diagnostic accuracy of XACT angiography in detecting stenosis of ≥ 50% and ≥ 75% and visualized by ICA was good (sensitivity: 74% and 62%, specificity: 99% and 99%, positive predictive value: 93% and 80%, and negative predictive value: 97% and 97%, respectively). These results suggest that XACT angiography with a very low amount of contrast medium may have strong clinical utility for screening coronary arteries in patients with renal dysfunction or undergoing clinical procedures such as pacemaker implantation.

The Role of Xuefu Zhuyu Decoction in Prevention of Contrast-Induced Nephropathy after Percutaneous Coronary Intervention

Objective

This study aimed to investigate the effect of Xuefu Zhuyu decoction on preventing contrast-induced nephropathy (CIN) after percutaneous coronary intervention (PCI).

Methods

A total of 256 patients undergoing selective PCI for coronary artery disease were consecutively enrolled and randomly divided into two groups: Group A (n = 126) and Group B (n = 130). Before and after PCI, all patients routinely received antiplatelet aggregation therapy, antilipidemic therapy, and hydration therapy. Besides routine therapy, patients in Group B received Xuefu Zhuyu decoction from 3 days before PCI to 3 days after PCI. Serum creatinine (Scr), estimated glomerular filtration rate (eGFR), superoxide dismutase (SOD), and malondialdehyde (MDA) were measured, respectively, at baseline (72 h before PCI) and at 24, 48, and 72 h after PCI.

Results

Compared with Group A, Group B presented a lower fluctuation of SCr and eGFR (P < 0.01). The incidence of CIN was less in Group B. According to the definition, CIN occurred in 5 patients (2.0%) in the intervention group and 5 (4.0%) in the control group (P=0.167). In terms of oxidative stress, Group B had a lower MDA (P < 0.05), but a higher SOD (P < 0.05).

Conclusions

Compared with the control group, Xuefu Zhuyu decoction intervention therapy increased the level of SOD and reduced MDA. The Xuefu Zhuyu decoction intervention group presented a higher level of eGFR at 24, 48, and 72 h after PCI in patients with coronary heart disease and a lower level of Scr. The results are propitious to prove that Xuefu Zhuyu decoction might play an antioxidative stress role in the prevention of CIN after PCI.

The investigation of TIMI risk index for prediction of contrast-induced acute kidney injury in patients with ST elevation myocardial infarction

Objective: Contrast-induced acute kidney injury (CI-AKI) is a well-known and life-threating complication in patients with ST-elevation myocardial infraction (STEMI) after primary percutaneous coronary intervention (PCI). Several studies demonstrated that the Thrombolysis in Myocardial Infarction (TIMI) Risk Index (TRI) is a useful risk model in predicting early mortality in patients with acute coronary syndrome. The objective of the present study is to evaluate the predictive value of admission TRI for the occurrence of CI-AKI in patients with STEMI treated with primary PCI.Methods: This retrospective study was consisted of a total of 660 consecutive STEMI patients who had undergone primary PCI from December 2015 to March 2017.The primary end-point was CI-AKI incidence after primary PCI during the in-hospital course.Results: The TRI of CI-AKI group was higher than the non-CI-AKI group (24.2 (19.3-32.2) vs. 17.5 (12.9-24.3), p < .001, respectively). In multivariable logistic regression analysis, TRI was found to be an independent predictors of CI-AKI (OR: 1.055, 95% CI: 1.027-1.083, p < .001). The discriminative power of TRI with regards to occurrence of CI-AKI was superior compared to its components.Conclusion: This study is the first to demonstrate that TRI can be used to predict the development of CI-AKI in patients with STEMI who undergo primary PCI. Health professionals might be able to use the TRI risk score to predict CI-AKI due to the simplicity and accessibility of this risk index.

Prevalence and Predictors of Contrast-Induced Nephropathy (CIN) in Patients with ST-Segment Elevation Myocardial Infarction (STEMI) Undergoing Percutaneous Coronary Intervention (PCI): A Meta-Analysis

Background

Contrast-induced nephropathy (CIN) becomes more and more frequent after percutaneous coronary intervention (PCI) in patients with ST-segment elevation myocardial infarction (STEMI). There have been no reported meta-analyses to determine the role of these risk factors in predicting CIN in patients with STEMI undergoing PCI. So we made this meta-analysis to summarize the incidence of CIN in patients with STEMI undergoing PCI and to study associations between CIN and several risk factors that are mentioned in most prevention guidelines.

Hypothesis

The overall incidence of CIN in patients with STEMI undergoing PCI is not low. Many risk factors could influence the occurrence of CIN, such as hypertension, diabetes mellitus (DM), and lower estimated glomerular filtration rate.

Methods

Databases, including PubMed, Embase, Cochrane Library, China National Knowledge Infrastructure (CNKI), and Chinese BioMedical (CBM), were searched for articles published before May 21, 2019, to identify all relevant studies on CIN. The pooled data were analyzed using either fixed-effects or random-effects models depending on heterogeneity (assessed via the I ² index).

Results

Twelve articles encompassing a total of 6342 patients were included. The overall pooled CIN incidence was 13.3% (95% CI: 10.4-17.1). The forest plots showed positive associations between CIN and the presence of hypertension, diabetes mellitus, history of prior myocardial infarction, age, damaged left anterior descending artery, Killip class ≥2, decreased left ventricular ejection fraction, lower estimated glomerular filtration rate, and left ventricular ejection fraction <40%; the odds ratios for these factors were 1.85 (95% CI: 1.57-2.18; p < 0.00001), 1.83 (95% CI: 1.47-2.29; p < 0.00001), 2.14 (95% CI: 1.46-3.14; p < 0.0001), 7.79 (95% CI: 5.24-10.34; p < 0.00001), 1.92 (95% CI: 1.15-3.22; p=0.01), 3.12 (95% CI: 2.21-4.40; p < 0.00001), -6.15 (95% CI: -9.52 to -2.79; p=0.0003), -15.06 (95% CI: -24.75 to -5.36; p=0.002), and 5.53 (95% CI: 1.10-27.95; p=0.04), respectively.

Conclusion

The overall incidence of CIN in patients with STEMI undergoing PCI was not low and was closely associated with hypertension, diabetes mellitus, history of prior myocardial infarction, age, damaged left anterior descending artery, Killip class ≥2, decreased left ventricular ejection fraction, lower estimated glomerular filtration rate, and left ventricular ejection fraction <40%.

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

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

Can Thrombus Burden Predict Contrast-Induced Nephropathy in Patients With ST-Segment Elevation Myocardial Infarction?

The incidence of contrast-induced nephropathy (CIN) increases in the range from patients with unstable angina to ST-segment elevation myocardial infarction (STEMI). Platelet activation has been associated with pathophysiology of nephropathy and thrombus burden in the infarct-related arteries. We investigated the impact of thrombus burden on CIN in patients with STEMI. We enrolled 883 patients with STEMI who received primary percutaneous coronary intervention. Patients were divided into groups according to thrombus burden and CIN development. Thrombus burden was scored based on thrombolysis in myocardial infarction thrombus grades (TGs). Thrombus grade 4 was defined as large thrombus burden (LTB), while thrombus burden <TG 4 was defined as small thrombus burden. A total of 126 (14.2%) patients with STEMI had CIN, while 313 (35.4%) patients had LTB. Compared to CIN (-) patients, CIN (+) patients were older, had lower hemoglobin levels, lower ejection fraction, and higher contrast media volume administration. Multivariate logistic regression analysis demonstrated that LTB, age, hypertension, and admission glomerular filtration rate were independent predictors of CIN (P = .016, P < .001, P = .028, P < .001, respectively). Thrombus burden, which is measurable during angiography, may be helpful in the determination of CIN risk in patients with STEMI.

Contrast-Induced Nephropathy and Long-Term Mortality After Percutaneous Coronary Intervention in Patients With Acute Myocardial Infarction

Abnormal hemodynamics is thought to contribute to the increased risk of contrast-induced nephropathy (CIN) and mortality. However, few studies focused on patients without abnormal hemodynamics (defined as hypotension, intra-aortic balloon pump usage) and reduced left ventricular ejection fraction (LVEF < 40%). Our study was to explore the impact of CIN on mortality in patients with acute myocardial infarction (AMI) undergoing percutaneous coronary intervention (PCI) with relative stable hemodynamics. In this observational study, we included 696 patients with AMI undergoing PCI without reduced LVEF and abnormal hemodynamics. The end point was long-term, all-cause mortality. During the mean follow-up of 2.79 years, CIN was detected in 110 (15.8%) patients. The total all-cause mortality was higher in CIN group than that in non-CIN group (24% vs 3.4%, P < .001). In the multivariate Cox analysis, CIN was an independent predictor of worse outcomes (adjusted hazard ratio [HR]: 2.97, 95% confidence interval: 1.46-6.06, P < .001) and significantly associated with long-term mortality, so did renal insufficiency (adjusted HR: 4.40, P < .001) and use of β-blockers (adjusted HR: 0.33, P < .001). Among patients with AMI, CIN independently predicted long-term mortality following PCI, regardless of LVEF impairment and abnormal hemodynamics.

Comparative Efficacy of Statins for Prevention of Contrast-Induced Acute Kidney Injury in Patients With Chronic Kidney Disease: A Network Meta-Analysis

Contrast-induced acute kidney injury (CI-AKI) is a common complication of iodinated contrast medium administration during cardiac catheterization. Statin treatment has been shown to be associated with reduced risk of CI-AKI; however, the results are inconsistent, especially for patients with chronic kidney disease (CKD). Thus, we conducted a network meta-analysis to evaluate the effects of statins in the prevention of CI-AKI. We systematically searched several databases (including, Embase, PubMed, the Cochrane Library, and ClinicalTrials.gov ) from inception to January 31, 2018. The primary outcome was occurrence of CI-AKI in patients with CKD undergoing cardiac catheterization. Both pairwise and network meta-analysis were performed. Finally, 21 randomized controlled trials with a total of 6385 patients were included. Results showed that statin loading before contrast administration was associated with a significantly reduced risk of CI-AKI in patients with CKD undergoing cardiac catheterization (odds ratio: 0.46; P < .05). Atorvastatin and rosuvastatin administered at high dose may be the most effective treatments to reduce incidence of CI-AKI, with no difference between these 2 agents.

High Dose of Atorvastatin for the Treatment of Contrast-Induced Nephropathy After Carotid Artery Stenting

Statins have been used to prevent contrast-induced nephropathy (CIN). However, the optimal dose of statins is still under controversy. This study aimed to investigate the optimal dose of atorvastatin for the treatment of CIN after carotid artery stenting (CAS). Seventy-six patients receiving selective CAS were randomized to receive 3 different dose of atorvastatin (low dose, 20 mg, n = 30; intermediate dose, 40 mg, n = 24; high dose, 60 mg, n = 22). Preoperatively and on day 3 postoperatively, the levels of serum creatinine, blood urea nitrogen, high-sensitivity C-reactive protein (hs-CRP), alanine aminotransferase (ALT), aspartate aminotransferase (AST), and creatine kinase (CK) were measured. Creatinine clearance (Ccr) and CIN incidence were calculated. In patients treated with high-dose atorvastatin, no significant change was observed in levels of serum creatinine (Scr), blood urea nitrogen (BUN), creatinine clearance, and high-sensitivity C-reactive protein after the CAS procedure (P > 0.05). The CIN incidence in the high-dose group (0%) was significantly lower than the low-dose (13.3%) and intermediate (8.3%) groups (P < 0.05). In the high-dose group, levels of alanine aminotransferase, aspartate aminotransferase, and creatine kinase were significantly increased after CAS (P < 0.05). Pretreatment with 40 mg of atorvastatin is both effective and safe in preventing CIN after CAS. Adverse events of the live and heart should be closely monitored during atorvastatin treatment.

Safe Hydration Volume to Prevent Contrast-induced Acute Kidney Injury and Worsening Heart Failure in Patients With Heart Failure and Preserved Ejection Fraction After Cardiac Catheterization

Few studies have investigated the efficacy and safety of hydration to prevent contrast-induced acute kidney injury (CI-AKI) and worsening heart failure (WHF) after cardiac catheterization in heart failure and preserved ejection fraction (HFpEF; HF and EF ≥50%) patients. We recruited 1206 patients with HFpEF undergoing cardiac catheterization with periprocedural hydration volume/weight (HV/W) ratio data and investigated the relationship between hydration volumes and risk of CI-AKI and WHF. Incidence of CI-AKI was not significantly reduced in individuals with higher HV/W [quartile (Q) 1, Q2, Q3, and Q4: 9.7%, 10.2%, 12.7%, and 12.2%, respectively; P = 0.219]. Multivariate analysis indicated that higher HV/W ratios were not associated with decreased CI-AKI risks [Q2 vs. Q1: odds ratio (OR), 0.95; Q3 vs. Q1: OR, 1.07; Q4 vs. Q1: OR, 0.92; all P > 0.05]. According to multivariate analysis, higher HV/W significantly increased the WHF risk (Q4 vs. Q1: adjusted OR, 8.13 and 95% confidence interval, 1.03-64.02; P = 0.047). CI-AKI and WHF were associated with a significantly increased risk of long-term mortality (mean follow-up, 2.33 years). For HFpEF patients, an excessively high hydration volume might not be associated with lower risk of CI-AKI but may increase the risk of postprocedure WHF.

High Plasma Exposure of Statins Associated With Increased Risk of Contrast-Induced Acute Kidney Injury in Chinese Patients With Coronary Artery Disease

The role of statins in reducing the incidence of contrast-induced acute kidney injury (CI-AKI) remains controversial. We sought to evaluate the association between CI-AKI and high plasma exposure of statins in coronary artery disease (CAD) patients undergoing coronary angiography (CAG). This association was first evaluated in 1,219 patients with CAD receiving atorvastatin (AT) therapy and validated in 635 patients receiving rosuvastatin (RST) therapy. The plasma concentrations of statins were quantified using validated UPLC-MS/MS methods and CI-AKI incidence was assessed during the first 48 h postoperatively. Among all participants (n = 1,854), AKI occurred in 57 of 1219 (4.7%) in the AT cohort and 30 of 635 (4.7%) in the RST cohort. High plasma AT-all exposure was associated with increased risk of CI-AKI (odds ratio [OR]: 2.265; 95% confidence interval [CI]: 1.609–3.187; p < 0.0001). Plasma AT-all concentration in the CI-AKI group (22.40 ± 24.63 ng/mL) was 2.6-fold higher than that in the control group (8.60 ± 9.65 ng/mL). High plasma RST exposure also significantly increased the risk of CI-AKI (OR: 2.281; 95% CI: 1.441–3.612; p = 0.0004). We further divided patients into two subgroups for each statin according to baseline renal function, and association between high plasma statin exposure and CI-AKI still remained highly significant in both subgroups. This study suggests for the first time that high plasma exposure of statins may significantly increase the risk of CI-AKI. Statins should be used with greater caution in CAD patients undergoing CAG to reduce the occurrence of CI-AKI.

Could late measurement of serum creatinine be missed for patients without early increase in serum creatinine following coronary angiography?

Most patients are discharged early (within 24 hours) after coronary angiography (CAG) and may miss identification the late (24-48 hours) increase in serum creatinine (SCr), whose characteristics and prognosis have been less intensively investigated.We prospectively recruited 3065 consecutive patients with SCr measurement, including only1344 patients with twice SCr measurement (both early and late). The late contrast-induced acute kidney injury (CI-AKI) was defined as significantly increase in SCr (≥0.3 mg/dL or ≥50%) not in early phase, but only in late phase after the procedure, and the early CI-AKI experienced a significantly increase in early phase.Overall, CI-AKI developed in 134 patients (10%), and the incidence of late and early CI-AKI were 3.6% and 6.4%, respectively. There were no difference in age, renal, and heart function, contrast volume among patients with late and early CI-AKI. With mean follow-up period of 2.45 years, long-term mortality (3 years, 29.7% and 35.6%, respectively, P = .553) was similar for patients with late and early CI-AKI. Cox analysis showed that both late (adjusted HR 2.05; 95% CI, 1.02-4.15) and early (adjusted HR 2.68; 95% CI, 1.57-4.59) CI-AKI was significantly associated with long-term mortality (all P < .001).Only late increase in SCr, as late CI-AKI, accounted for about one-third of CI-AKI incidence and has similar good predictive value for long-term mortality with that of an early increase, early CI-AKI, among patients with SCr measured twice, supporting the importance of late repeating SCr measurement after CAG, even without an early significant increase in SCr.

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

BACKGROUND

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

MATERIALS AND METHODS

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

RESULTS

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

CONCLUSIONS

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

miR‑21 attenuates contrast‑induced renal cell apoptosis by targeting PDCD4

Contrast medium (CM) is widely used in cardiac catheterization; however, it may induce acute kidney injury or renal failure, although the underlying mechanism remains to be elucidated. MicroRNA‑21 (miR‑21) is involved in renal disease and has been indicated to regulate cellular apoptosis and fibrosis, although its role in CM‑induced renal cell injury is unknown. The present study examined the expression and potential targets of miR‑21 in human renal proximal tubular epithelial (HK‑2) cells following CM treatment. CM induced renal cell apoptosis and decreased miR‑21 expression. The expression level of the apoptosis regulator protein, B‑cell lymphoma 2 (Bcl‑2) was upregulated, whereas that of the apoptosis regulator, Bcl‑2‑associated X protein (Bax) was downregulated upon transfection of miR‑21 mimics; miR‑21 overexpression additionally directly inhibited the expression of programmed cell death protein 4 (PDCD4), as determined by a dual luciferase reporter assay, and PDCD4 silencing reduced the rate of HK‑2 cell apoptosis. The results of the present study indicated that miR‑21 protected renal cells against CM‑induced apoptosis by regulating PDCD4 expression.

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

BACKGROUND

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

METHODS

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

RESULT

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

CONCLUSION

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

CLINICAL TRIAL REGISTRATION

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

Association of left ventricular ejection fraction with contrast-induced nephropathy and mortality following coronary angiography or intervention in patients with heart failure

Background

Left ventricular ejection fraction (LVEF) is the most widely used parameter to evaluate the cardiac function in patients with heart failure (HF). However, the association between LVEF and contrast-induced nephropathy (CIN) is still controversial. Therefore, the aim of this study is to evaluate the association of LVEF with CIN and long-term mortality following coronary angiography (CAG) or intervention in patients with HF.

Methods

We analyzed 1,647 patients with HF (New York Heart Association [NYHA] or Killip class >1) undergoing CAG or intervention, including 207 (12.57%) patients with reduced LVEF (HFrEF), 238 (14.45%) with mid-range LVEF (HFmrEF) and 1,202 (72.98%) with preserved LVEF (HFpEF). CIN was defined as an absolute increase of ≥0.5 mg/dL or a relative increase of ≥25% from baseline serum creatinine within 48–72 h after contrast medium exposure. Multivariable logistic regression and Cox proportional hazards regression analyses were performed to identify the association between LVEF, CIN and long-term mortality, respectively.

Results

Overall, 225 patients (13.7%) developed CIN. Individuals with lower LVEF were more likely to develop CIN (HFrEF, HFmrEF and HFpEF: 18.4%, 21.8% and 11.2%, respectively; P<0.001), but without a significant trend after adjusting for the confounding factors (HFrEF vs HFpEF: odds ratio [OR] =1.01; HFmrEF vs HFpEF: OR =1.31; all P>0.05). However, advanced HF (NYHA class >2 or Killip class >1) was an independent predictor of CIN (adjusted OR =1.54, 95% confidence interval [CI], 1.07–2.22; P=0.019). During the mean follow-up of 2.3 years, reduced LVEF (HFrEF group) was significantly associated with increased mortality (HFrEF vs HFpEF: adjusted hazard ratio =2.88, 95% CI, 1.77–4.69; P<0.001).

Conclusion

In patients with HF undergoing CAG or intervention, not worsened LVEF but advanced HF was associated with an increased risk of CIN. In addition, reduced LVEF was an independent predictor of long-term mortality following cardiac catheterization.

Post-Hoc Study: Intravenous Hydration Treatment in Chinese Patients with High Risk of Contrast-Induced Nephropathy Following Percutaneous Coronary Intervention

Contrast-induced nephropathy (CIN) develops after the injection of iodinated contrast media. This is a post hoc analysis of the data obtained from the TRUST study, which was a prospective, multicentre, observational study conducted to evaluate the safety and tolerability of the contrast medium iopromide in patients undergoing cardiac catheterization from August 2010 to September 2011 in China, conducted to explore the current status, trends and risk predictors of hydration treatment. The status of hydration to prevent CIN in each patient was recorded. Of the total 17,139 patients from the TRUST study (mean age, 60.33 ± 10.38 years), the overall hydration usage was 46.1% in patients undergoing percutaneous coronary intervention (PCI) and 77.4%, 51.7%, and 48.5% in patients with pre-existing renal disease, diabetes mellitus, and hypertension, respectively. The proportion of hydration use increased from 36.5% to 55.5% from August 2010 to September 2011, which was independently associated with risk predictors like older age, pre-existing renal disease, hypertension, diabetes mellitus, prior myocardial infarction, ST segment elevation MI, high contrast dose, multi-vessel disease and reduced LVEF (<45%). Overall, the usage of intravenous hydration treatment for patients with a high risk of CIN following PCI was high in China.

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.

Contrast-Induced Acute Kidney Injury in Patients Undergoing Carotid Artery Stenting: An Underestimated Issue

Carotid artery stenting (CAS) is increasingly offered to patients with carotid artery stenosis. Although CAS is a less invasive (and thus more attractive) alternative compared with carotid endarterectomy, it requires the use of contrast material. A possible side effect from the use of contrast material during CAS is the development of contrast-induced acute kidney injury (CI-AKI). This review discusses the incidence/prevalence and clinical significance of CI-AKI developing after CAS. We also discuss possible measures to reduce the incidence of CI-AKI after CAS.

Antioxidant and renoprotective effects of sphingosylphosphorylcholine on contrast-induced nephropathy in rats

Contrast induced nephropathy (CIN) is a major cause of morbidity, and increased costs as well as an increased risk of death. This study was evaluated effects of exogenous sphingosylphosphorylcholine (SPC) administration on CIN in rats. Eight animals were included in each of the following eight groups: control, control phosphate-buffered solution (PBS), control SPC 2, control SPC 10, CIN, CIN PBS, CIN SPC 2 and CIN SPC 10. The induced nephropathy was created by injected with 4 g iodine/kg body weight. SPC was administered 3 d at a daily two different doses of 2 μm/mL and 10 μm/mL intraperitoneally. The severity of renal injury score was determined by the histological and immunohistochemical changes in the kidney. Malondialdehyde (MDA), nitric oxide (NO) and superoxide dismutase (SOD) were determined to evaluate the oxidative status in the renal tissue. Treatment with 2 and 10 μM SPC inhibited the increase in renal MDA, NO levels significantly and also attenuated the depletion of SOD in the renal injuryCIN. These data were supported by histopathological findings. The inducible nitric oxide synthase positive cells and apoptotic cells in the renal tissue were observed to be reduced with the 2 and 10 μM SPC treatment. These findings suggested that 2 and 10 μM doses can attenuate renal damage in contrast nephropathy by prevention of oxidative stress and apoptosis. The low and high dose SPC may be a promising new therapeutic agent for CIN.

Bridging translation for acute kidney injury with better preclinical modeling of human disease

The current lack of effective therapeutics for patients with acute kidney injury (AKI) represents an important and unmet medical need. Given the importance of the clinical problem, it is time for us to take a few steps back and reexamine current practices. The focus of this review is to explore the extent to which failure of therapeutic translation from animal studies to human studies stems from deficiencies in the preclinical models of AKI. We will evaluate whether the preclinical models of AKI that are commonly used recapitulate the known pathophysiologies of AKI that are being modeled in humans, focusing on four common scenarios that are studied in clinical therapeutic intervention trials: cardiac surgery-induced AKI; contrast-induced AKI; cisplatin-induced AKI; and sepsis associated AKI. Based on our observations, we have identified a number of common limitations in current preclinical modeling of AKI that could be addressed. In the long term, we suggest that progress in developing better preclinical models of AKI will depend on developing a better understanding of human AKI. To this this end, we suggest that there is a need to develop greater in-depth molecular analyses of kidney biopsy tissues coupled with improved clinical and molecular classification of patients with AKI.

Readout-segmented echo-planar imaging in diffusion-weighted imaging of the kidney: comparison with single-shot echo-planar imaging in image quality

OBJECTIVE

The purpose of this study was to compare the image quality of readout-segmented echo-planar imaging (RS-EPI) and that of standard single-shot echo-planar imaging (SS-EPI) in the kidney in a rat model.

MATERIALS AND METHODS

Twelve Wistar rats undergoing MRI examinations were imaged with two diffusion-weighted (DW) imaging protocols: a standard SS-EPI and a new RS-EPI protocol, both with a 1.0 × 1.0 × 3.0 mm voxel. The two groups of diffusion-weighted images were independently scored on geometric distortion, image blurring, signal dropout, and the overall image quality by two radiologists. Signal-to-noise ratio (SNR) and apparent diffusion coefficient (ADC) were measured on both sequences. Inter-rater agreement (IRA) was evaluated by Fleiss kappa (κ) and inter-class correlation coefficient (ICC) statistics. Comparisons of image qualities were made by Wilcoxon signed-rank test and paired-sample t test.

RESULTS

Both RS-EPI and SS-EPI had good IRAs in scoring image qualities (κ = 0.607-0.833) and measuring renal ADCs (ICC = 0.828-0.945). Compared to SS-EPI, RS-EPI produced less geometric distortion (median score 1.5 versus 2.5, p < 0.0001), less image blurring (1.75 versus 2.0, p = 0.0003), less signal dropout (1.0 versus 3.0, p = 0.0001), and a lower score in overall image artifacts (4.25 versus 7.25; p < 0.0001). RS-EPI had higher SNR of renal DW images than SS-EPI (p < 0.001). The intra-variability of ADCs in cortex, outer medulla, and inner medulla ranged from 9.6% to 11.1% (Pearson correlation coefficient ρ = 0.675-0.729; p < 0.001) between the two protocols.

CONCLUSION

We showed that for DWI of the kidney at 1.0 × 1.0 × 3.0 mm(3) voxel sizes, the new protocol provided better image quality than standard SS-EPI protocol.

The Impact of Remote Ischemic Pre-Conditioning on Contrast-Induced Nephropathy in Patients Undergoing Coronary Angiography and Angioplasty: A Double-Blind Randomized Clinical Trial

BACKGROUND AND OBJECTIVE

Contrast-induced nephropathy (CIN) is an acute major complication following intravascular administration of iodinated contrast agents; however, the best approach for preventing CIN is not clear. Remote ischemic pre-conditioning (RIPC) is a new, non-pharmacological method that has been considered for the prevention of CIN following coronary angiography. This study assessed the effects of RIPC with four brief episodes of upper limb ischemia and reperfusion in the prevention of contrast-induced nephropathy (CIN) after coronary angiography and/or angioplasty.

METHODS

In this double-blind randomized clinical trial, we enrolled 51 patients with chronic stable angina and non-ST elevation acute coronary syndrome (NSTE.ACS), and they underwent coronary angiography and/or angioplasty. Standard fluid therapy with normal saline was prescribed for all patients before and after the procedure. The patients were divided into two groups, i.e., a study group of patients who had undergone RIPC intervention and a control group of patients who had not undergone RIPC. One hour before the procedure, a sphygmomanometer cuff was placed around one arm and inflated up to 50 mmHg above the systolic pressure for five minutes; then, the cuff was deflated for another five minutes, and this cycle was repeated four times. The patients' serum creatinine levels were measured at baseline and 48 hours after the procedure, and the incidence of CIN was calculated.

RESULTS

Twenty-one males and 30 females were studied in two groups, i.e., an RIPC intervention group (n = 25) and a control group (n = 26) that were homogenous considering baseline characteristics. No significant difference was observed in the mean level of serum creatinine between the two groups at a post-intervention time of 48 hours (RICP: 1.74 ± 0.70 mg/dL vs.

CONTROL

1.75 ± 0.87 mg/dL; P = 0.64). However, a lower incidence rate of CIN was observed 48 hours after the administration of the contrast medium in the RIPC group, but it was not statistically significant (RIPC: 23.1% vs.

CONTROL

12.0%; P = 0.30).

CONCLUSION

It seems that adequate fluid therapy is still the most effective strategy for preventing CIN and that RIPC might have additional protective effects in very high risk patients, such as those with severe renal insufficiency and heart failure.

Bridging Translation by Improving Preclinical Study Design in AKI

Despite extensive research, no therapeutic interventions have been shown to prevent AKI, accelerate recovery of AKI, or reduce progression of AKI to CKD in patients. This failure in translation has led investigators to speculate that the animal models being used do not predict therapeutic responses in humans. Although this issue continues to be debated, an important concern that has not been addressed is whether improvements in preclinical study design can be identified that might also increase the likelihood of translating basic AKI research into clinical practice using the current models. In this review, we have taken an evidence-based approach to identify common weaknesses in study design and reporting in preclinical AKI research that may contribute to the poor translatability of the findings. We focused on use of N-acetylcysteine or sodium bicarbonate for the prevention of contrast-induced AKI and use of erythropoietin for the prevention of AKI, two therapeutic approaches that have been extensively studied in clinical trials. On the basis of our findings, we identified five areas for improvement in preclinical study design and reporting. These suggested and preliminary guidelines may help improve the quality of preclinical research for AKI drug development.

Rosuvastatin Treatment for Preventing Contrast-Induced Acute Kidney Injury After Cardiac Catheterization: A Meta-Analysis of Randomized Controlled Trials

We performed a meta-analysis of randomized controlled trials (RCTs) to evaluate the protective effects of rosuvastatin on contrast-induced acute kidney injury (CI-AKI) and major adverse cardiovascular events (MACEs) in patients undergoing cardiac catherization.PubMed, MEDLINE, Web of Science, EMBASE, ClinicalTrials.gov, and the Cochrane Central RCTs were searched for RCTs from inception to May 2015, to compare rosuvastatin for preventing CI-AKI with placebo treatment in patients undergoing cardiac catherization.Five RCTs with a total of 4045 patients involving 2020 patients pretreated with rosuvastatin and 2025 control patients were identified and analyzed. Patients treated with rosuvastatin had a 51% lower risk of CI-AKI compared with the control group based on a fixed-effect model (OR = 0.49, 95% CI = 0.37-0.66, P < 0.001), and showed a trend toward a reduced risk of MACEs (OR = 0.62, 95% CI = 0.36-1.07, P = 0.08). A subgroup analysis showed that studies with Jadad score ≥3 showed a significant reduction of CI-AKI (OR = 0.53, 95% CI, 0.38-0.73, P < 0.001). However, the risk of CI-AKI did not significantly differ in the studies with Jadad score <3 (OR = 0.54, 95% CI, 0.13-2.24, P = 0.40). In addition, the rosuvastatin treatment showed no effect for preventing CI-AKI in patients with chronic kidney disease (CKD) undergoing elective cardiac catherization (I = 0%, OR = 0.81, 95% CI = 0.41-1.61, P = 0.55).This updated meta-analysis demonstrated that preprocedural rosuvastatin treatment could significantly reduce the incidence of CI-AKI, with a trend toward a reduced risk of MACEs in patients undergoing cardiac catheterization. However, rosuvastatin treatment did not seem to be effective for preventing CI-AKI in CKD patients undergoing elective cardiac catheterization.

Insulin Resistance Increases the Risk of Contrast-Induced Nephropathy in Patients Undergoing Elective Coronary Intervention

We assessed the influence of insulin resistance (IR) on the development of contrast-induced nephropathy (CIN) in patients (n = 719) undergoing elective percutaneous coronary intervention (PCI). Patients were divided into diabetes mellitus (DM = 242), nondiabetic IR (IR = 120), and nondiabetic insulin sensitivity (IS = 357) groups according to medical history and homeostasis model assessment insulin resistance index. Serum creatinine (SCr) and estimated glomerular filtration rate (eGFR) were measured before and 72 hours after PCI. There were no differences in SCr and eGFR among the groups before PCI; SCr increased and eGFR decreased significantly in the DM and IR groups post-PCI (P < .001). The incidence of CIN in the IR group was as high as in the DM group and were both significantly higher than in the IS group (6.7% vs 8.7% vs 2.2%, P < .05). Multivariate logistic regression analysis showed DM (odds ratio [OR] = 1.19, 95%CI = 1.08-1.510, P < .001), HOMA-IR (OR = 1.39, 95%CI = 1.23-1.58, P < 0.001), and eGFR (OR = 0.88, 95%CI = 0.84-0.92, P < .001) were independent risk factors in predicting CIN. Screening IR patients and taking appropriate prophylactic strategy before PCI may reduce the incidence of CIN.

Safe contrast volumes for preventing contrast-induced nephropathy in elderly patients with relatively normal renal function during percutaneous coronary intervention

The aim of this study was to evaluate contrast media volume to creatinine clearance (V/CrCl) ratio for predicting contrast-induced nephropathy (CIN) and to determine a safe V/CrCl cut off value to avoid CIN in elderly patients with relatively normal renal function during percutaneous coronary intervention (PCI). We prospectively enrolled 1020 consecutive elderly patients (age ≥65 years) with relative normal renal function (baseline serum creatinine <1.5 mg/dL) undergoing PCI. Receiver operating characteristic (ROC) curves were used to identify the optimal cut off value of V/CrCl for detecting CIN. The predictive value of V/CrCl for CIN was assessed with a multivariate logistic regression. Thirty-nine patients (3.8%) developed CIN. There was a significant association between a higher V/CrCl ratio and CIN risk (P < 0.001). ROC curve analysis indicated that a V/CrCl ratio of 2.74 was a fair discriminator for CIN (C statistic = 0.68). After adjusting for other known CIN risk factors, V/CrCl ratios >2.74 remained significantly associated with CIN (odds ratio = 3.21, 95% confidence interval [CI] 1.45-7.09, P = 0.004) and worse long-term mortality (hazard ratio = 1.96, 95% CI 1.14-3.38, P = 0.016). A V/CrCl ratio >2.74 was a significant independent predictor of CIN and was independently associated with long-term mortality in elderly patients with relatively normal renal function.

Effect of rhBNP on renal function in STEMI-HF patients with mild renal insufficiency undergoing primary PCI

This study aims to investigate the effect of recombinant human brain natriuretic peptide (rhBNP) on renal function and contrast-induced nephropathy (CIN) incidence in ST-segment elevation myocardial infarction and heart failure (STEMI-HF) patients with mild renal insufficiency undergoing primary percutaneous coronary intervention (PCI). A total of 116 participants were randomized into rhBNP (rhBNP, n = 57) and nitroglycerin group (NIT, n = 59), receiving intravenous rhBNP or nitroglycerin from admission to 72 h after PCI. Renal function was assessed by serum creatinine (SCr), estimated glomerular filtration rate (eGFR), Cystatin-C (Cys-C) and β2-microglobulin before and after primary PCI, and calculated the incidence of CIN within 72 h after PCI. There were no significant differences in SCr, eGFR and β2-microglobulin between the two groups (P > 0.05, respectively). Compared with the NIT group, the total urinary volume within 72 h was higher while the level of Cys-C at 24 and 72 h after PCI was lower in the rhBNP group. rhBNP was associated with a decline in the incidence of CIN (12.28 vs. 28.81 %, P < 0.05). No differences were detected in mortality and re-hospitalization in 3 months between the two groups. The incidence of renal injury was not different between rhBNP and nitroglycerin in STEMI-HF patients with mild renal insufficiency. However, infusion of rhBNP was associated with a decline in incidence of CIN.

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.

The Role of Statins in Preventing Contrast-Induced Acute Kidney Injury

The incidence of contrast-induced acute kidney injury (CI-AKI) is rising due to increased use of coronary angiography and percutaneous coronary intervention. Many agents, including statins, have been evaluated in several studies for the prevention of CI-AKI. To date, there have been 14 prospective randomized studies regarding the efficacy of statins on the patient. Most of these studies and 3 recent meta-analyses have concluded that statins should be used for this purpose, even in patients with reduced low-density lipoprotein cholesterol levels. However, there are also conflicting results, most likely due to marked heterogeneity of patient characteristics, dosage and administration patterns of statins, definition of CI-AKI, and different statistical analyses. In conclusion, it is uncertain whether statins should be prescribed to prevent CI-AKI in the absence of other indications.

Contrast-induced nephropathy; A literature review

CONTEXT

Contrast-induced nephropathy (CIN) is a common cause of acute kidney dysfunction.

EVIDENCE ACQUISITIONS

Directory of Open Access Journals, Google Scholar, PubMed, EBSCO and Web of Science have been searched.

RESULTS

It is necessary to identify at risk patients at early stages to implement preventive strategies to decrease the incidence of this nephropathy. However, mechanisms of CIN have not fully explained yet. It seems that mechanisms which mediated by nitric oxide and prostaglandin-induced vasodilatation have been played a crucial role in the CIN. Hemodynamic changes of renal blood flow, which causes hypoxia in the renal medulla and direct toxic effects of contrast media on renal cells, are thought to contribute to the pathogenesis of CIN. Contrast media is normally divided into iso-osmolar, low-osmolar, and high-osmolar. N-acetylcysteine is considered as one of the best choices to prevent CIN in high-risk groups.

CONCLUSIONS

The first aim to prevent CIN is identifying high-risk subjects and controlling associate risk factors. As significant differences existed between contrasts agents due to their physicochemical properties, low-osmolar or iso-osmolar contrast media should be used to prevent CIN in at-risk patients. The volume of contrast media should be as low as possible.