Acetylcysteine for prevention of contrast nephropathy: meta-analysis

Low-Molecular-Weight Synthetic Antioxidants: Classification, Pharmacological Profile, Effectiveness and Trends

Mounting research has been performed and published on natural antioxidants, more so than on synthetic ones, as key molecules that control oxidative damage and its pathway to disease. Since the discovery of vitamins, various fully synthetic or natural-identical compounds have been developed as stable small molecules translated into constantly active and completely controlled products which are widely exploited in the food and pharmaceutical industries. There is currently a debate within the literature about their mechanism of action, bioavailability, safety and real benefit for human health. Using a semiquantitative method and eligible criteria of selection, this review aimed to provide a very useful classification of antioxidants and a comprehensive cross-disciplinary description of 32 approved synthetic/natural-identical antioxidants, in terms of regulatory, antioxidant mechanism of action, safety issues, pharmacological properties, effectiveness in human health, timeline and future trends. Enriched interpretation of the data was obtained from summary bibliometrics, useful to portray the “good antioxidant” within the period 1966–2021 and, hopefully, to encourage further research.

Contrast-induced nephropathy in non-cardiac vascular procedures, a narrative review: Part 1

Contrast-induced nephropathy (CIN) is an important complication of iodinated contrast medium (CM) administration, which is associated with both short- and long-term adverse outcomes (e.g., cardiorenal events, longer hospital stay, and mortality). CIN has been mainly studied in relation to cardiac procedures, but it can also occur following non-cardiac vascular interventions. This is Part 1 of a narrative review summarizing the available literature on CIN after non-cardiac vascular diagnostic or therapeutic procedures for aortic aneurysm and carotid stenosis. We discuss the definition, pathophysiology, incidence, risk factors, biomarkers, and consequences of CIN in these settings, as well as preventive strategies and alternatives to limit iodinated CM use. Physicians and vascular surgeons should be aware of CM-related adverse events and the potential strategies to avoid them. Clearly, more research in this important field is required.

Impact of RAAS Blockers on Contrast-Induced Nephropathy in Patients With Renal Insufficiency: A Meta-Analysis

The effect of renin-angiotensin-aldosterone system (RAAS) blockers [angiotensin-converting enzyme inhibitors (ACEIs) and angiotensin receptor blockers] on Contrast-induced nephropathy (CIN) is unclear in patients with renal insufficiency. Thus, we conduct a meta-analysis to evaluate the association between the administration of RAAS blockers and CIN in patients with renal insufficiency. We searched PubMed, EMBASE, and Cochrane Library for relevant studies published before September 2019. The primary outcome was the incidence of CIN, and the secondary outcome was the changes in serum creatinine (SCr) from baseline to postprocedure (ΔSCr). Pooled odds ratio (OR) or weighted mean difference (WMD) with their 95% confidence interval (CIs) for the CIN incidence, ΔSCr were used to calculate original data. A total of 8 studies were included in the meta-analysis. Compared with controls, ACEI/angiotensin receptor blocker increased the risk of CIN (OR = 1.61, 95% CI 1.14-2.28, I = 30%; P = 0.007), whereas this association was not significant in Chinese patients (OR = 1.07, 95% CI 0.65-1.77, I = 19%, P = 0.79). The total weighted mean differences of the ΔSCr were 0.06 mg/dL (95% CI: 0.01-0.11, I = 82%; P = 0.03). Administration of RAAS blockers in patients with renal insufficiency was associated with a significantly higher incidence of CIN, whereas it did not show a significant effect on Chinese patients.

Renal Function: Implications on the Surgical Treatment of RCC

The good oncologic results after partial nephrectomy for stage 1 RCC show that radical nephrectomy is an overtreatment in most cases, and that many healthy nephrons are removed unnecessarily. However, partial nephrectomy is a difficult operation, with increased blood loss and a higher risk of complications. Therefore, the advantage of preserved function has to be weighed up against the increased trauma of surgery in each individual patient, and the assessment of preoperative function may influence this decision, among other factors such as comorbidities and age. In most studies, renal function has been assessed by means of estimated glomerular filtration rate, and this parameter is very helpful for long-term studies in large populations. However, more precise measurement based on clearance studies are sometimes required for more sophisticated investigations. The technique of partial nephrectomy has evolved substantially in recent years, resulting in the preservation of more nephrons, less damage to the remaining parenchyma, less blood loss, and a decreased risk of complications. The introduction of minimally invasive surgery for this purpose has also decreased the overall morbidity of surgery. In the long-term, chronic kidney disease may result in increased cardiac mortality. There is ongoing discussion on this problem, however, this potential negative influence on overall survival is not only influenced by the rate of renal insufficiency, but also to a great extent by other comorbidities such as hypertension and diabetes. Therefore, in addition to providing the best surgery for any given patient, we have to make sure that the treatment of the comorbidities will also be part of our patient management, since the risk of cardiac failure may be greater than the risk of poor oncologic outcome.

Renal protective effect of N-acetylcysteine with stepwise ramping voltage against extracorporeal shock wave lithotripsy-induced renal injury: a prospective randomized trial

PURPOSE

To evaluate the role of combination of N-acetylcysteine with stepwise ramping voltage in renal protection against the ischemic, vascular and oxidative effects of extracorporeal shock wave lithotripsy.

PATIENTS AND METHODS

A prospective randomized trial on 164 adult patients scheduled for ESWL for single renal stones. Patients with radio-lucent stones, diabetes, hypertension, febrile UTI, and preoperative albuminuria were excluded from the study. Patients were randomized into one of four groups. Group A patients received maximal fixed voltage of ESWL. Group B patients received stepwise ramping voltage of ESWL. Group C patients received fixed maximal voltage with N-acetylcysteine (NAC) 600 mg/bid from 48 h before to 24 h after the procedure. Group D patients received gradual ramping voltage with NAC. Urinary β₂-microglobulin, 24 h albumin and N-acetyl-β-D-glucosaminidase/creatinine ratio at 1 day and 5 days post-ESWL and the stone free rate at 2 weeks were measured.

RESULTS

Group D was the only group that showed no significant difference pre and post ESWL in urinary albumin, β₂-microglobulin and N-acetyl-β-D-glucosaminidase/creatinine ratio. Post hoc analysis revealed no significant difference between group B and group C in albumin, β₂-microglobulin N-acetyl-β-D-glucosaminidase/creatinine ratio, but both of them had significantly lower levels than group A and significantly higher levels than group D. There was no statistically significant difference between all groups in the stone free rate at 2 weeks.

CONCLUSION

N-acetylcysteine protects the kidney against ESWL-induced renal injuries especially if combined with stepwise ramping voltage.

Prophylactic hemodialysis following coronary angiography and one-year outcomes in non-dialysis patients with chronic kidney disease: A propensity-matched study

BACKGROUND/PURPOSE

Prophylactic hemodialysis after coronary angiography in patients with chronic kidney disease (CKD) prevents contrast nephropathy; however, the one-year outcomes are unclear. This study aimed to investigate the one-year outcomes of prophylactic hemodialysis against standard treatment in patients with CKD who underwent coronary angiography.

METHODS

A cohort study of 359 patients with CKD, coronary artery disease (CAD), and serum creatinine levels of 176.8-530.4 μmol/L, who were referred for elective coronary angiography was conducted. Propensity score matching identified 118 patient pairs for outcome comparisons. The hemodialysis group underwent prophylactic hemodialysis after coronary angiography, whereas the control group received standard treatment. The study's primary outcome was free from dialysis was considered the primary outcome, whereas the secondary outcome was overall survival. Unadjusted estimates of the probability of free from dialysis and overall survival were computed using Kaplan-Meier survival curves and log-rank tests. Cox proportional-hazards regression models were used in determining the risk factors associated with ESRD and mortality.

RESULTS

During a mean 9.3 months follow-up duration, the hemodialysis group had significantly better free from dialysis (85.6% vs. 64.4%; P = 0.002) and overall survival (85.4% vs. 78.5%; P = 0.008) rates than the control group. Cox proportional-hazards regression analyses of the propensity score-matched patients showed that the hemodialysis group had reduced risks for ESRD and mortality (hazard ratios, 0.32 and 0.48, respectively).

CONCLUSION

Prophylactic Hemodialysis following coronary angiography was associated with reduced ESRD and mortality risks in CKD patients with CAD, who did not routinely undergo dialysis.

Endovascular Aneurysm Repair Assisted by CO2 Digital Subtraction Angiography and Intraoperative Contrast-Enhanced Ultrasonography: Single-Center Experience

BACKGROUND

Allergy to iodinated contrast (IC) agent and advanced chronic kidney disease are major limitations to endovascular repair (EVAR) of abdominal aortic aneurysms (AAAs). We describe our experience combining CO₂-assisted EVAR with intraoperative contrast-enhanced ultrasound (CEUS) in an attempt to avoid contrast-induced allergy or nephropathy.

METHODS

Observational cohort study using prospectively acquired data on patients undergoing CO₂-assisted EVAR in single institution. EVAR planning was performed using computed tomographic angiography or magnetic resonance aortography in patients contraindicated for IC. Patients were considered if their estimated glomerular filtration rate was <40 mL/min and anatomically suitable for conventional infrarenal EVAR. Outcomes of interest included technical success rate and reintervention rates, total radiation dose, length of hospital stay, and graft kinking or migration.

RESULTS

Fifteen patients (10 male) were treated across a 5-year period. Technical success was achieved in all cases. Completely IC-free EVAR was performed in 9 cases, whereas the remaining 6 required IC administration for adjunct procedures. CO₂ completion angiography detected all type I endoleaks (2 Ia and 1 Ib) but was less sensitive to type II. Intraoperative CEUS confirmed all type I and 2 cases of type II endoleaks. Median hospital stay was 4 days. No significant deterioration in renal function was seen postoperatively.

CONCLUSIONS

In patients with abdominal aortic aneurysms and with contraindication for IC, a combined approach of using CO₂ digital subtraction angiography and CEUS can be used safely and efficiently to minimize or obviate the need for IC agents with satisfactory mid-term results.

Percutaneous Endovascular Aortic Aneurysm Repair with INCRAFT Endograft Guided by CO2 Digital Subtraction Angiography in Patients with Renal Insufficiency

Iodinated contrast is the most common contrast agent used during endovascular abdominal aneurysm repair (EVAR). However, its use may worsen kidney function in patients with renal insufficiency. Previous studies have demonstrated the safety and effectiveness of carbon dioxide (CO₂)-EVAR. Here, we report cases of three male patients with mild renal insufficiency (mean age: 79 years) that successfully underwent CO₂-EVAR using INCRAFT ultra-low profile endografts. CO₂ angiography provided the necessary vascular roadmap for safe and effective percutaneous EVAR, eliminating the need for iodinated contrast media and preventing contrast-induced nephropathy.

The protective effect of klotho against contrast-associated acute kidney injury via the antioxidative effect

As oxidative stress is one major factor behind contrast-associated acute kidney injury (CA-AKI), we investigated the protective effect of klotho against CA-AKI via the antioxidative effect. In in vitro experiments, cells (NRK-52E) were divided into the following three groups: control, iopamidol, or iopamidol + recombinant klotho (rKL) groups. Moreover, cell viability was measured with the Cell Counting Kit-8 assay, and oxidative stress was examined with 2',7'-dichlorodihydrofluorescein diacetate fluorescence intensity. RT-PCR and Western blot analysis were performed to assess propidium iodide klotho expression, and Bax-to-Bcl-2 and apoptosis ratios were evaluated with annexin V/Hoechst 33342 staining. Furthermore, we knocked down the klotho gene using siRNA to verify the endogenous effect of klotho. In our in vivo experiments, oxidative stress was evaluated with the thiobarbituric acid-reactive substance assay, and apoptosis was evaluated with the Bax-to-Bcl-2 ratio and cleaved caspase-3 immunohistochemistry. Additionally, cell and tissue morphology were investigated with transmission electron microscopy. In both in vitro and in vivo experiments, mRNA and protein expression of klotho significantly decreased in CA-AKI mice compared with control mice, whereas oxidative stress and apoptosis markers were significantly increased in CA-AKI mice. However, rKL supplementation mitigated the elevated apoptotic markers and oxidative stress in the CA-AKI mouse model and improved cell viability. In contrast, oxidative stress and apoptotic markers were more aggravated when the klotho gene was knocked down. Moreover, we found more cytoplasmic vacuoles in the CA-AKI mouse model using transmission electron microscopy but fewer cytoplasmic vacuoles in rKL-supplemented cells. The present study shows that klotho in proximal tubular cells can protect against CA-AKI via an antioxidative effect.

Effect of renal insufficiency and diabetes mellitus on in-hospital mortality after acute coronary syndromes treated with primary PCI. Results from the ALKK PCI Registry

BACKGROUND

It is known that patients with acute coronary syndromes (ACS) and diabetes mellitus (DM) are at higher risk for in-hospital adverse events. However, we hypothesized that the higher event rate is due to the patients' subgroup with renal failure (RF), a common sequel of DM.

METHODS AND RESULTS

We used data of the prospective ALKK-PCI registry including all consecutive percutaneous coronary interventions (PCI) for ACS of 48 hospitals between 2008 and 2013. We divided 69,651 patients in four groups according to their history of DM and RF (GFR < 60 ml/min). All-cause, in-hospital mortality of the following four groups: noDM/noRF, DM/noRF, DM/RF, RF/noDM, was: 3.5%, 6.6%, 21.9%, and 14.1% for STEMI and 1.5%, 2.1%, 7.2%, and 5.4% for NSTE-ACS. In a multivariate analysis we looked for independent mortality-predictors. Odds ratios with confidence intervals for the following variables: DM without RF, DM with RF, RF without DM were: 1.62 (1.37-1.90), 3.02 (2.43-3.76), and 2.13 (1.80-2.52) for STEMI and 1.20 (0.99-1.45), 2.72 (2.18-3.88), and 2.08 (1.69-2.56) for NSTE-ACS. We also calculated mortality in four groups (60-90, 45-60, 45-30, <30 ml/min) according to the estimated glomerular filtration rate (eGFR). Mortality rates were: 5.0%, 12.8%, 17.7%, and 31.5% for STEMI and 2.1%, 3.8%, 7.1%, and 12.0% for NSTE-ACS (p for trend <0.0001 for both).

CONCLUSIONS

In-hospital death after PCI in patients with ACS and DM is mainly observed in the subgroup with co-existing RF. In a multivariate analysis, DM without RF was a significant mortality-predictor in STEMI, but not in NSTE-ACS. RF, irrespective of co-existent DM, was a stronger predictor than DM alone for both ACS-types (OR > 3) and mortality increased with decreasing eGFR.

Indoxyl sulfate induces myotube atrophy by ROS-ERK and JNK-MAFbx cascades

Accumulations of uremic toxins has been widely recognized as the major trigger of skeletal muscle loss in chronic kidney disease (CKD), which is defined as uremic sarcopenia. Current study was aimed to examine the effects of representative uremic toxin, indoxyl sulfate (IS), on C2C12 myotubes. The incubation of IS (from 0.1 mM to 1.2 mM) exerted the reduction in myotube diameter without cell survival impairment. Elevated oxidative stress and mitogen-activated protein kinase (MAPKs) phosphorylation were observed after IS stimulation for 1 and 24 h. After N-acetylcysteine (NAC) treatment as antioxidants, the recovery in IS-induced decrease myotube diameter and ERK phosphorylation was observed. This findings were implicit the transduction of p-ERK in IS-induced ROS toxicity. Moreover, the increase of LC3β was found closely with IS treatment in C2C12 myotubes. The reverse effect of NAC on LC3β expression revealed the ROS-responsibility in autophagy regulation of CKD myopathy. The evaluation of IS-treated proteasome system showed increased phospho-myosin light chain, along with the upregulation of muscle atrophy F-box (MAFbx) mRNA and protein. This alteration in MAFbx was also identified in nephrectomy-induced CKD model. Besides, the inhibition of p-JNK was capable to attenuate IS-induced upward change in MAFbx protein expression. These findings indicated that IS-mediated myotube atrophy may manipulate through ROS-ERK axis and JNK-MAFbx regulation in C2C12 cells.

Pharmacological interventions for the prevention of contrast-induced acute kidney injury in high-risk adult patients undergoing coronary angiography: a systematic review and meta-analysis of randomised controlled trials

Objective

Quantify the efficacy of strategies to prevent contrast-induced acute kidney injury (CI-AKI) in high-risk patients undergoing coronary angiography (CAG) with or without percutaneous coronary intervention (PCI).

Background

CI-AKI remains a common problem. The renoprotective efficacy of existing pharmacological agents remains uncertain in high-risk populations.

Methods

Systematic review and meta-analysis of randomised controlled trials (RCTs) to compare different strategies versus hydration in patients with chronic kidney disease (CKD) undergoing CAG±PCI. Primary outcome was incident CI-AKI. Fixed-effects meta-analyses estimated ORs, 95% CIs and heterogeneity.

Results

Forty-eight RCTs were included. Seven pharmacological strategies were evaluated by multiple RCTs and 10 by one RCT each. These had varying risk of bias; >25% of trials were at high risk of performance bias. Five strategies significantly reduced the odds of CI-AKI: N-acetylcysteine (NAC) (27 trials, 5694 participants; OR=0.77, 95% CI 0.65 to 0.91, p=0.002, I²=36%), ascorbic acid (four trials, 759 participants; OR=0.59, 95% CI 0.39 to 0.89, p=0.01, I²=0%), statin (two trials, 3234 participants; OR=0.59, 95% CI 0.39 to 0.89, p=0.75, I²=0%), trimetazidine (two trials, 214 participants; OR=0.27, 95% CI 0.10 to 0.71, p=0.01, I²=0%) and nicorandil (two trials, 389 participants; OR=0.47, 95% CI 0.23 to 0.94, p=0.03, I²=52%). Theophylline had a similar, but non-significant, effect. A subgroup analysis found that the benefit of NAC was highest in patients requiring a high-contrast dose.

Conclusions

Several drugs are renoprotective in patients with CKD undergoing CAG±PCI. The evidence is strongest for NAC. We recommend that NAC should be used when a high dose of contrast is anticipated.

Trial registration number

PROSPERO registration CRD42014014704.

Open Science Framework link: https://osf.io/vxg7d/?view_only=62bad0404b18405abd39ff2ead2575a8

Prevention of Contrast Nephropathy in Critically Ill Patients Using Acetylcysteine and Theophylline

Compared with periprocedural hydration alone, acetylcysteine with hydration significantly reduces the risk of contrast nephropathy in patients with chronic renal insufficiency by 50%. For elective contrast procedures, acetylcysteine should be given in a dose of 600 mg twice daily the day before and on the procedure day. For emergency procedures, a high dose intravenous regimen (150 mg/kg in 500 mL normal saline over 30 minutes immediately before contrast followed by 50 mg/kg in 500 mL normal saline over 4h) is effective. Given the low cost and good side-effect profile of acetylcysteine, it would seem prudent to give this drug with intravenous fluids to all critically ill patients scheduled for intravenous or intraarterial contrast procedures. Theophylline in a dose of 200 mg or 2.5 mg/kg IV 30 minutes before contrast may be an effective alternative for emergency procedures. Although its benefit compared with periprocedural hydration alone seems less well established, theophylline is a particularly attractive option for emergency procedures.

Baseline Chloride Levels are Associated with the Incidence of Contrast-Associated Acute Kidney Injury

Although hypo- and hyperchloremia have been associated with worsening renal outcomes, there has been no study that correlates hypo- and hyperchloremia and the incidence of contrast-associated acute kidney injury (CA-AKI). A total of 13,088 patients with less than 2.0 mg/dL of serum creatinine (Cr) who underwent contrast-enhanced abdominal CT (CECT) were included. Patients were divided into 3 groups based on Cl (the hypo-, normo- and hyperchloremia groups). Patients were also classified by baseline Cr (<1.2; the ‘Normal Cr group’ and 1.2–2.0 mg/dL; the ‘Slightly increased Cr group’). Multivariate logistic regression analysis was used to reveal the association between Cl and CA-AKI. Among patients, 2,525 (19.3%) and 241 (1.8%) patients were classified in the hypo- and hyperchloremia group. The incidence of CA-AKI was significantly lower in the normochloremia group (4.0%) compared to the hypo- (5.4%) and hyperchloremia groups (9.5%). On multivariate logistic regression, hypochloremia was significantly associated with the incidence of CA-AKI compared with normochloremia (1.382, P = 0.002). Moreover, hypochloremia was still significantly associated with the incidence of CA-AKI in ‘Normal Cr group’ compared with normochloremia (1.314, P = 0.015), while hyperchloremia did not show significant association with CA-AKI incidence. In conclusion, hypochloremia might be associated with the incidence of CA-AKI even in patients who have normal-range Cr levels.

Efficacy and safety of a balanced salt solution versus a 0.9% saline infusion for the prevention of contrast-induced acute kidney injury (BASIC trial): a study protocol for a randomized controlled trial

Background

Contrast-induced acute kidney injury (CI-AKI) is one of the most common causes of iatrogenic kidney injury and, therefore, its prevention is an important issue. However, whether the administration of 0.9% saline is the optimal prophylaxis method remains uncertain due to its supra-physiologic chloride component. In particular, recent studies suggest that chloride-restricted solutions showed superiority over 0.9% saline in several clinical settings.

Methods/design

The investigators designed a multicenter randomized controlled trial to compare the efficacy of a balanced salt solution and 0.9% saline in CI-AKI prophylaxis. This study will recruit patients who are scheduled for contrast-enhanced computed tomography (CT) scans with CI-AKI prophylaxis. In this study, participants will be randomized into two study arms; the study group will receive a balanced salt solution, and the control group will receive 0.9% saline. Fluids will be administered as designated in the protocol before and after the CT scan, and an evaluation of baseline clinical status will be performed by obtaining blood and urine samples. During the follow-up visits, the incidence of CI-AKI and long-term outcomes, including the start of renal replacement therapy or all-cause mortality, will be assessed.

Discussion

To our knowledge, this study will be the first study assessing the preventive value of a balanced salt solution over 0.9% saline for CI-AKI. If the trial shows that the balanced salt solution is as effective for CI-AKI prophylaxis as 0.9% saline, the use of the balanced salt solution could be promoted due to the reduced possibility of consequent metabolic acidosis compared to 0.9% saline.

Trials registration

ClinicalTrials.gov, ID: NCT02799368. Registered on 14 June 2016.

Electronic supplementary material

The online version of this article (doi:10.1186/s13063-017-2202-2) contains supplementary material, which is available to authorized users.

Con: Meta-analysis: some key limitations and potential solutions

Meta-analysis, a statistical combination of results of several trials to produce a summary effect, has been subject to criticism in the past, mainly for the reasons of poor quality of included studies, heterogeneity between studies meta-analyzed and failing to address publication bias. These limitations can cause the results to be misleading, which is important if policy and practice decisions are based on systematic reviews and meta-analyses. We elaborate on these limitations and illustrate them with examples from the nephrology literature. Finally, we present some potential solutions, notably, education in meta-analysis for evidence producers and consumers as well as the use of individual patient data for meta-analyses.

Key role of oxidative stress in animal models of aminoglycoside nephrotoxicity revealed by a systematic analysis of the antioxidant-to-nephroprotective correlation

The clinical utility of aminoglycoside antibiotics is partly limited by their nephrotoxicity. Co-administration of a variety of candidate nephroprotectants has been tested at the preclinical level. According to a recent meta-analytic study, antioxidants are the only family of compounds with enough preclinical documentation to draw solid conclusions on their class nephroprotective capacity in animal models. In this study a systematic analysis of the relation between the level of antioxidation and the level of nephroprotection was performed. A regression model is presented which crosses the y-axis (i.e. the axis representing the level of nephroprotection) very nearly the zero value, meaning that maximal prevention of the oxidative stress induced by aminoglycosides results in almost maximal nephroprotection. This indicates that oxidative stress plays a central role in the hierarchy of pathophysiological mechanisms underlying aminoglycoside nephrotoxicity. In addition, this model may potentially serve: i) as a standard to evaluate the role of the antioxidant effect of candidate nephroprotectants; ii) to reveal additional, antioxidant-independent effects among those compounds providing more nephroprotection than that expected from its antioxidant activity; and thus iii) to discriminate and focus most effective nephroprotectants on clinical usage.

Percutaneous Coronary Intervention Versus Optimal Medical Therapy for Stable Angina in Advanced CKD: A Decision Analysis

BACKGROUND

Percutaneous coronary intervention (PCI) use is low in the setting of stable symptomatic angina in individuals with advanced chronic kidney disease (CKD) despite high cardiovascular risk in this population, and PCI is frequently deferred out of concern for precipitating dialysis therapy. Whether this is appropriate is uncertain, and patient-centered data comparing the relative risks and benefits of continued medical therapy versus PCI in patients with advanced CKD and stable angina are scarce.

STUDY DESIGN

Decision analysis.

SETTING & POPULATION

Hypothetical cohort of individuals with advanced CKD (stages 4-5 with estimated glomerular filtration rates ≤ 20mL/min/1.73m2) and stable angina.

MODEL, PERSPECTIVE, & TIMELINE

A Markov model with a Monte Carlo simulation through 12 cycles, that is, 3 years of 3-month intervals, with 10,000 microsimulations predicted mean quality-adjusted life-years.

INTERVENTION

PCI first, medical management, or dialysis (hemodialysis [HD]) followed by PCI.

OUTCOMES

Outcomes modeled were progression to HD therapy (for those not assigned to the preemptive HD strategy), catheter infection, and death.

RESULTS

Our analysis showed mean quality-adjusted life-years of 1.103 ± 0.69 for PCI first, 1.088±0.70 for medical management, and 0.670±0.58 for HD followed by PCI. Probabilistic sensitivity analysis found PCI as the preferred strategy > 60% of the time.

LIMITATIONS

Values for probabilities and utilities were estimated and/or derived from multiple sources that were not uniform in their populations in terms of age, comorbid condition burden, and degree of kidney failure, and several simplifying assumptions were made.

CONCLUSIONS

Our analysis demonstrates that quality-adjusted life expectancy is similar for the PCI first and medical management strategies in patients with advanced CKD with stable angina and that the decision depends on patient preferences other than those incorporated in our model. Both strategies are superior to preemptive dialysis.

Sodium Bicarbonate-Ascorbic Acid Combination for Prevention of Contrast-Induced Nephropathy in Chronic Kidney Disease Patients Undergoing Catheterization

BACKGROUND

Sodium bicarbonate and ascorbic acid have been proposed to prevent contrast-induced nephropathy (CIN). The present study evaluated the effect of their combined use on CIN incidence.Methods and Results:We prospectively enrolled 429 patients with chronic kidney disease (CKD: baseline estimated glomerular filtration rate <60 mL/min/1.73 m²) prior to elective coronary catheterization. CIN was defined as absolute (≥0.5 mg/dL) or relative (≥25%) increase in serum creatinine within 72 h. In the saline hydration (n=218) and combined sodium bicarbonate+ascorbic acid (n=211) groups, a total of 1,500-2,500 mL 0.9% saline was given before and after the procedure. In addition, the combination group received 20 mEq sodium bicarbonate and 3 g ascorbic acid i.v. before the procedure, followed by 2 g ascorbic acid after the procedure and a further 2 g after 12 h. There were no significant differences between the basic characteristics and contrast volume in the 2 groups. CIN occurred in 19 patients (8.7%) in the saline group, and in 6 patients (2.8%) in the combined treatment group (P=0.008).

CONCLUSIONS

Combined sodium bicarbonate and ascorbic acid could prevent CIN following catheterization in CKD patients.

N-Acetylcysteine and Sodium Bicarbonate Versus N-Acetylcysteine and Standard Hydration for the Prevention of Radiocontrast-Induced Nephropathy Following Coronary Angiography

Background:

Radiocontrast-induced nephropathy (RCIN) is thought to be caused by renal ischemia and direct toxic effects on renal tubular cells brought on by contrast media. The combination of N-acetylcysteine (NAC) and hydration fluids (NaCI 0.9% or 0.45%) has been shown to reduce these deleterious effects and is commonly given prior to coronary angiography. The use of bicarbonate as the hydration anion has been shown to confer additional RCIN protection compared with that of saline. However, limited data are available regarding whether sodium bicarbonate hydration, proven to be beneficial alone, can further improve outcomes when given with NAC.

Objective:

To compare the incidence of RCIN in patients undergoing coronary angiography after pretreatment with NAC plus sodium bicarbonate hydration or NAC plus standard hydration (NaCI 0.9% or 0.45%).

Methods:

A retrospective, single-center study evaluated 96 patients who underwent coronary angiography from January 2002 to December 2005. Data were collected through electronic chart reviews.

Results:

Forty-seven patients received NAC and sodium bicarbonate for hydration and 49 received NAC and standard hydration. Baseline characteristics between the 2 groups were similar. All patients received at least one 600 mg oral dose of NAC before angiography was performed. RCIN was defined as impairment of renal function occurring within 72 hours of administering contrast media, indicated by an absolute increase in the serum creatinine level of 0.5 mg/dL or more. A total of 12.2% of the patients receiving NAC and standard hydration developed RCIN, versus 14.9% of the patients in the NAC and sodium bicarbonate group (p = 0.713).

Conclusions:

The addition of sodium bicarbonate to NAC does not appear to confer additional protection against the development of RCIN. Prospective, randomized, placebo-controlled trials are warranted to definitively determine how this combination compares with NAC and standard hydration in preventing RCIN.

Radiocontrast-Induced Acute Renal Failure

The intravascular administration of iodinated radiocontrast media can lead to acute renal dysfunction. Even small changes in renal function have been associated with increased morbidity and mortality, making the prevention of radiocontrast nephropathy of paramount importance. This review summarizes the principal risk factors for radiocontrast nephropathy and evidence-based preventive strategies that should be used to limit its occurrence. Risk factors for radiocontrast nephropathy include preexistent kidney disease, diabetes mellitus, dose of radiocontrast used, advanced congestive heart failure, and intravascular volume depletion. Proven preventive measures include volume expansion with intravenous saline or sodium bicarbonate and the use of low-osmolar or iso-osmolar radiocontrast media. Studies evaluating N-acetylcysteine have been conflicting, with meta-analyses suggesting a small beneficial effect. Studies of other pharmacologic agents have not demonstrated clinical benefit.

Contrast-Induced Nephropathy After Computed Tomography in Stable CKD Patients With Proper Prophylaxis: 8-Year Experience of Outpatient Prophylaxis Program

Conflicting data have been reported on the clinical significance of contrast-induced nephropathy after CT scan (CT-CIN). In addition, the epidemiologic characteristics and clinical outcomes of CT-CIN following proper prophylactic intervention remain elusive.We examined the incidence, risk factors, and outcomes of CT-CIN in stable chronic kidney disease (CKD) patients using data collected from our outpatient CT-CIN prophylaxis program conducted between 2007 and 2014. The program recruited patients with an estimated glomerular filtration rate (eGFR) <60 mL/min/1.73 m using an electronic health record-based pop-up alert system and provided an identical protocol of CIN prophylaxis to all patients.A total of 1666 subjects were included in this study, and 61 of the 1666 subjects (3.7%) developed CT-CIN. Multivariate analysis showed that baseline eGFR, diabetes mellitus, and low serum albumin were significant risk factors for CT-CIN. The generalized additive model analysis revealed a nonlinear relationship between the baseline eGFR and the risk of CT-CIN. In this analysis, the risk of CT-CIN began to increase below an eGFR threshold of 36.8 mL/min/1.73 m. To assess the outcomes of CT-CIN, patients with and without CT-CIN were compared after propensity score-based 1:2 matching. CT-CIN did not increase the mortality rate of patients. However, patients with CT-CIN were significantly more likely to start dialysis within 6 months of follow-up, but not after those initial 6 months.CT-CIN developed in only a small number of stable CKD patients who received proper prophylactic intervention, and the risk of CT-CIN was increased in patients with more advanced CKD. Despite the low incidence, CT-CIN conferred a non-negligible risk for the initiation of dialysis in the acute period, even after prophylaxis.

Incidental CT Findings of Patients Who Admitted to ER Following a Traffic Accident

Objective

The aim of this study was to investigate and analyze incidental CT findings of traffic injury patients discharged from the ER, and to determine overall notification rates.

Methods

All traffic injury-related patient records between 01.06.2013–01.03.2013 were obtained from Derince Training and Research Hospital Emergency Service using patient files and the hospital database. Brain, thorax and/or abdominal CT images of 340 patients aged between 0 to 84 years were included in the study. ER observation forms were investigated for the patients who had incidental findings on CT scanning and overall notification rates were recorded.

Results

Mean age of the 363 cases was 31.2 (SD 17.9, min 0, max 84) and 35.5% of patients were female (n=129) and 64.5% were male (n=234). A total of 537 CT scans were performed on 363 patients. 147, 319 and 71 CT scans were performed on the thorax, brain and abdominal, respectively. 27.3% (n=99) of scan results showed the presence of a coincidental pathology. The most common disease on scans were bone lesions (8%, n=29), followed by sinus abnormalities (7.7%, n=28). Incidental findings ratio in patients aged over 60 was 60.8%, while under 60 was 24.8%. It was found that seven patients (7.1%) were informed about the imaging results.

Conclusion

Most of the incidental findings were found to be benign; however, 16.5% of them were considered to require in-depth investigation. Further investigations are needed to understand the clinical relevance of these findings and their effects on patients.

Evaluation of different sodium bicarbonate regimens for the prevention of contrast medium-induced nephropathy

INTRODUCTION

The rapid decline in renal function caused by radiographic contrast agents usually is transient, but it can result in chronic kidney disease. The pathophysiology of contrast-induced nephropathy (CIN) is poorly understood, but it may include acute hypoxia-induced oxidative stress and free radicals generated within the acid environment of the renal medulla. Thus, the alkalization of urine by sodium bicarbonate has been regarded as resulting in the reduction of CIN. The aim of this study was to determine whether a long-duration sodium bicarbonate regimen is more effective than a short-duration regimen in reducing CIN.

METHODS

One hundred patients were assigned randomly to treatment with sodium bicarbonate solution using either the short regimen (intravenous bolus 3 mL/kg/h of 166 mEq/L sodium bicarbonate for 1 hour immediately before radiocontrast) or the long regimen (initial intravenous bolus of 3 mL/kg/h of 166 mEq/L sodium bicarbonate for 6 hr). Patients with renal dysfunction (estimated glomerular filtration rate [eGFR], 60 mL/min/1.73 m(2) or less) who underwent elective or emergent coronary angiography (CAG) with/without percutaneous coronary intervention (PCI) at Nephrology Department (Theodor Bilharz Research Institute) were enrolled in the study. Data were analyzed by SPSS version 12, using Kruskal Wallis, ANOVA, Chi square test and Spearman rank correlation coefficient.

RESULTS

There was a significant increase in serum creatinine and a decrease in eGFR 48 hr post-intervention in group 1 (short regimen) with no statically difference regarding those parameters group 2 (long regimen). Serum potassium clearly was decreased significantly post procedure in both groups.

CONCLUSIONS

The results of our study indicated that the long regimen of bicarbonate supplementation was a more effective strategy to prevent CIN than the short regimen.

Effects of N-acetyl cysteine on renal functions evaluated by blood neutrophil gelatinase-associated lipocalin levels in geriatric patients undergoing coronary artery bypass grafting

Objective:

Recent conflicting studies on the renal effects of N-acetyl cysteine (NAC) after cardiac surgery have been published. The aim of this study was to evaluate the renal effects of NAC using neutrophil gelatinase-associated lipocalin (NGAL) blood levels in elderly patients undergoing coronary artery bypass grafting (CABG).

Methods:

This randomized, double-blinded, placebo-controlled study was conducted among geriatric patients (>65 years) scheduled to undergo CABG. A total of 60 consecutive patients were randomly assigned to 2 groups. The first group received I.V. NAC (n=30) and the second group received placebo (n=30) at induction of anesthesia and then for 20 h. NGAL values were determined and conventional renal function tests were performed. Statistical analysis was performed using SPSS 17.0 (IL, Chicago, USA). A p value of <0.05 was considered statistically significant

Results:

Plasma creatinine levels at 24 h postoperatively were significantly higher in the placebo group than in the NAC group (1.41±0.63 vs. 1.13±0.35; p<0.05). The mean serum NGAL levels at 3 h postoperatively were higher in the placebo group than in the NAC group (104.94±30.51 vs. 87.82±25.18; p<0.05). NGAL levels were similar between the groups at all other measurement time points. Plasma creatinine levels of ≥1.5 mg/dL or >25% of the baseline value at any time during the study period were observed in 27% of patients in the NAC group and 37% of patients in the placebo group; the difference was statistically significant (p<0.05).

Conclusion:

In the present study, we found that I.V. NAC infusion in elderly patients undergoing CABG reduced the incidence of acute kidney injury as determined by blood NGAL and creatinine levels.

Nephroprotective potential of carnitine against glycerol and contrast-induced kidney injury in rats through modulation of oxidative stress, proinflammatory cytokines, and apoptosis

OBJECTIVE

Contrast media (CM) are a major cause of nephropathy in high-risk patients. The aim of this study was to examine the effects of carnitine (CAR) in advanced nephrotoxicity due to CM administration in rats with glycerol-induced renal functional disorder.

METHODS

40 rats were divided randomly into five groups (n = 8): (1) healthy group; (2) glycerol only (GLY); (3) glycerol and CM (GLY + CM); (4) glycerol, CM and 200 mg kg(-1) carnitine (CAR200, Carnitene(®); Sigma-tau/Santa Farma, Istanbul, Turkey); and (5) glycerol, CM and 400 mg kg(-1) carnitine (CAR400). Kidney injury was induced with a single-dose, intramuscular injection of 10 ml kg(-1) body weight (b.w.) of GLY. CAR was administered intraperitoneally. CM (8 ml kg(-1) b.w. iohexol, Omnipaque™; Opakim Medical Products, Istanbul, Turkey) was infused via the tail vein to the rats in Groups 3-5.

RESULTS

l-carnitine administration significantly decreased serum creatinine and blood urea nitrogen levels. Superoxide dismutase and glutathione activity increased significantly in the treatment groups compared with the nephrotoxic groups. CAR400 significantly reduced malondialdehyde levels to healthy levels. In the treatment groups, tumour necrosis factor (TNF)-α, transforming growth factor 1β, interleukin 1β and caspase-3 gene expression decreased compared with the nephrotoxic groups. TNF-α and nuclear factor kappa-beta (NF-κB) protein expression increased after CM and CAR administration reduced both TNF-α and NF-κB expressions. Histopathologically, hyaline and haemorrhagic casts and necrosis in proximal tubules increased in the nephrotoxicity groups and decreased in the CAR groups.

CONCLUSION

The results reveal that l-carnitine protects the oxidant/antioxidant balance and decreases proinflammatory cytokines and apoptosis in CM-induced nephrotoxicity in rats with underlying pathology.

ADVANCES IN KNOWLEDGE

Depending on the underlying kidney pathologies, the incidence of CM-induced nephropathy (CIN) increases. Therefore, this is the best model to represent clinically observed CIN.

Evaluation of N-acetylcysteine for the prevention of contrast-induced nephropathy

BACKGROUND

Contrast-induced nephropathy (CIN) remains a leading cause of acute renal failure in hospitalized patients. N-Acetylcysteine has been studied previously for the prevention of CIN, resulting in mixed findings.

OBJECTIVE

The objective of this study was to determine the impact of N-acetylcysteine on the development of CIN in order to guide its use at community, teaching hospitals.

METHODS

Patients admitted between January 1 and December 31, 2011, receiving intravenous radiocontrast dye were included if they were compliant with two or more of the following conditions: baseline serum creatinine >1.2 mg/dL or estimated creatinine clearance <50 mL/min, age ≥75 years, diabetes mellitus, heart failure, or hypertension. The primary outcome was the difference in the proportion of patients in each group (N-acetylcysteine or no N-acetylcysteine) who developed CIN, which was defined as a ≥0.5 mg/dL increase in serum creatinine or a ≥25% increase in serum creatinine within 12-96 hours post-exposure to contrast.

RESULTS

A total of 302 patients were included, 151 who received N-acetylcysteine and 151 who did not receive N-acetylcysteine. Patients who received N-acetylcysteine had significantly worse renal function at baseline than those who did not receive N-acetylcysteine (mean pre-contrast serum creatinine, 1.41 vs. 0.95 mg/dL, p<0.0001). A lower proportion of patients developing CIN was observed between those who received N-acetylcysteine and those who did not receive N-acetylcysteine (10.2% vs. 21.8%, p=0.0428).

CONCLUSIONS

The use of N-acetylcysteine was likely associated with a reduced incidence of CIN in patients at risk for CIN development. Based on these results, hospitals may benefit from the development of a protocol to guide the appropriate use of N-acetylcysteine.

Application of continuous renal replacement therapy for acute kidney injury in elderly patients

This study aims to analyze the factors that affect the prognosis of continuous renal replacement therapy (CRRT) in elderly patients with acute kidney injury (AKI). Data obtained from 41 elderly patients with AKI who underwent CRRT in our department between January 2001 and December 2010 was retrospectively evaluated in this study. The enrolled patients were 80 to 100 years old, with a mortality of 60.98%. The mean Acute Physiology and Chronic Health Evaluation II (APACHE II) score was 27.8±5.6 points, and the mean risk coefficient was 0.80±0.10. The APACHE II score of the survival group was significantly higher than that of the death group. The comparisons of therapeutic dosages between <25 mL/(kg⋅h) and 25-50 mL/(kg⋅h), and between 25-50 mL/(kg⋅h) and >50 mL/(kg⋅h) all had no statistical significance. The prognosis of CRRT and the number of involved organs were related to the APACHE II score. Logistic regression analysis revealed that the number of involved organ, APACHE II score, mechanical ventilation, and hypoalbuminemia were the major risk coefficients that affected the prognosis of patients with bedside hemofiltration. The turnover of elderly CRRT patients was related to the number of involved organs, APACHE II score, mechanical ventilation, hypoalbuminemia, and other factors. The APACHE II score was the important reference index of CRRT starting time and could predict mortality risk.

Contrast media controversies in 2015: imaging patients with renal impairment or risk of contrast reaction

OBJECTIVE

The incidence and significance of complications related to intravascular contrast material administration have become increasingly controversial. This review will highlight current thinking regarding the imaging of patients with renal impairment and those at risk for an allergiclike contrast reaction.

CONCLUSION

The risk of contrast-induced acute kidney injury remains uncertain for patients with an estimated glomerular filtration rate (GFR) less than 45 mL/min/1.73 m(2), but if there is a risk, it is greatest in those with estimated GFR less than 30 mL/min/1.73 m(2). In this population, low-risk gadolinium-based contrast agents appear to have a large safety margin. Corticosteroid prophylaxis remains the standard of care in the United States for patients identified to be at high risk of a contrast reaction, but it has an incomplete mitigating effect on contrast reaction rates and the number needed to treat is large.

Oral hydration for prevention of contrast-induced acute kidney injury in elective radiological procedures: a systematic review and meta-analysis of randomized controlled trials

Background:

The reports on efficacy of oral hydration treatment for the prevention of contrast-induced acute kidney injury (CIAKI) in elective radiological procedures and cardiac catheterization remain controversial.

Aims:

The objective of this meta-analysis was to assess the use of oral hydration regimen for prevention of CIAKI.

Materials and Methods:

Comprehensive literature searches for randomized controlled trials (RCTs) of outpatient oral hydration treatment was performed using MEDLINE, EMBASE, Cochrane Database of Systematic Reviews, Cochrane Central Register of Controlled Trials Systematic Reviews, and clinicaltrials.gov from inception until July 4^th, 2014. Primary outcome was the incidence of CIAKI.

Results:

Six prospective RCTs were included in our analysis. Of 513patients undergoing elective procedures with contrast exposures,45 patients (8.8%) had CIAKI. Of 241 patients with oral hydration regimen, 23 (9.5%) developed CIAKI. Of 272 patients with intravenous (IV) fluid regimen, 22 (8.1%) had CIAKI. Study populations in all included studies had relatively normal kidney function to chronic kidney disease (CKD) stage 3. There was no significant increased risk of CIAKI in oral fluid regimen group compared toIV fluid regimen group (RR = 0.94, 95% confidence interval, CI = 0.38-2.31).

Conclusions:

According to our analysis,there is no evidence that oral fluid regimen is associated with more risk of CIAKI in patients undergoing elective procedures with contrast exposures compared to IV fluid regimen. This finding suggests that the oral fluid regimen might be considered as a possible outpatient treatment option for CIAKI prevention in patients with normal to moderately reduced kidney function.

The immunological benefit of higher dose N-acetyl cysteine following mechanical ventilation in critically ill patients

BACKGROUND

Sepsis complication is a major cause of death in multiple trauma critically ill patients. Defensin (cysteine rich anti-microbial peptides), as an important component of immune system, might play an important role in this process. There is also rising data on immunological effects of N-acetyl-cysteine (NAC), a commonly used anti-oxidant in oxidative stress conditions and glutathione (GSH) deficiencies. The aim of the present study was to evaluate the potential beneficial effects of NAC administration on multiple trauma patients with sepsis.

METHODS

In a prospective, randomized controlled study, 44 multiple trauma critically ill patients who were mechanically ventilated and met the criteria of sepsis and admitted to the intensive care unit (ICU) were randomized into two groups . Control group received all standard ICU therapies and NAC group received intravenous NAC 3 gr every 6 hours for 72 hours in addition to standard therapies. Acute Physiology and Chronic Health Evaluation II (APACHE II) and Sequential Organ Failure Assessment (SOFA) scores, length of ICU stay, ICU mortality were recorded. Levels of serum Immunoglobulin M (IgM), Human β-Defensin 2 (HβD2) and GSH were assessed at baseline and 24, 72, 120 hours after intervention.

RESULTS

During a period of 13-month screening, 44 patients underwent randomization but 5 patients had to be excluded. 21 patients in NAC group and 18 patients in control group completed the study. For both groups the length of ICU stay, SOFA score and systemic oxygenation were similar. Mortality rate (40% vs. 22% respectively, p = 0.209) and ventilator days (Mean ± SD 19.82 ± 19.55 days vs. 13.82 ± 11.89 days respectively, p = 0.266) were slightly higher for NAC group. IgM and GSH levels were similar between two groups (p = 0.325, 0.125 respectively), HβD2 levels were higher for NAC group (at day 3).

CONCLUSION

High dose of NAC administration not only did not improve patients' outcome, but also raised the risk of inflammation and was associated with increased serum creatinine.

Different interventions in preventing contrast-induced nephropathy after percutaneous coronary intervention

BACKGROUND

This study aimed to observe the preventive potential of different hydration solutions on contrast-induced nephropathy (CIN) after percutaneous coronary intervention.

METHODS

We initially screened 627 patients who were admitted to the Division of Cardiology, Beijing Anzhen Hospital between October 2010 and October 2011. The research subjects were randomly divided into four groups and were given: normal physiological saline (PS), sodium bicarbonate (SB), oral administration of PS + N-acetylcysteine (NAC) (PS + NAC), or oral administration of SB + NAC (SB + NAC). These patients were administered a hypotonic nonionic contrast agent, and the incidence of CIN in each group was observed.

RESULTS

The total incidence rate of CIN was 4.47 %, while the CIN incidence rates in the PS group, the SB group, the PS + NAC group and the SB + NAC group were 3.11, 5.03, 4.46 and 5.33 %, respectively. The differences between these groups were not statistically significant (P = 0.238), and for patients with diabetes and/or renal dysfunction, the incidence rates of CIN among the four groups did not show statistically significant differences (P = 0.238, 0.156, 0.287).

CONCLUSION

Use of PS, SB, and NAC caused no significant reduction in the incidence of CIN, but in high-risk patients with diabetes and/or renal dysfunction, SB + NAC might be superior to the application of isotonic crystalloid solution.

Renal protection: preconditioning for the prevention of contrast-induced nephropathy

As the numbers of interventional procedures are rising exponentially, identification of those patients at risk for renal complications has become even more important. Renal complications have been associated with increased morbidity and mortality after interventions. Risk factors have been studied to help identify those patients at increased risk for developing contrast-induced nephropathy. Hydration and medications have been studied as protective measures to decrease risk of renal complications. Preconditioning patients with intravenous hydration has been found to be the most helpful in circumventing postprocedural contrast-induced nephropathy.

Side effects of radiographic contrast media: pathogenesis, risk factors, and prevention

Radiocontrast media (RCM) are medical drugs used to improve the visibility of internal organs and structures in X-ray based imaging techniques. They may have side effects ranging from itching to a life-threatening emergency, known as contrast-induced nephropathy (CIN). We define CIN as acute renal failure occurring within 24-72 hrs of exposure to RCM that cannot be attributed to other causes. It usually occurs in patients with preexisting renal impairment and diabetes. The mechanisms underlying CIN include reduction in medullary blood flow leading to hypoxia and direct tubule cell damage and the formation of reactive oxygen species. Identification of patients at high risk for CIN is important. We have reviewed the risk factors and procedures for prevention, providing a long list of references enabling readers a deep evaluation of them both. The first rule to follow in patients at risk of CIN undergoing radiographic procedure is monitoring renal function by measuring serum creatinine and calculating the eGFR before and once daily for 5 days after the procedure. It is advised to discontinue potentially nephrotoxic medications, to choose radiocontrast media at lowest dosage, and to encourage oral or intravenous hydration. In high-risk patients N-acetylcysteine may also be given.

[Perioperative acute kidney injury and failure]

Perioperative period is very likely to lead to acute renal failure because of anesthesia (general or perimedullary) and/or surgery which can cause acute kidney injury. Characterization of acute renal failure is based on serum creatinine level which is imprecise during and following surgery. Studies are based on various definitions of acute renal failure with different thresholds which skewed their comparisons. The RIFLE classification (risk, injury, failure, loss, end stage kidney disease) allows clinicians to distinguish in a similar manner between different stages of acute kidney injury rather than using a unique definition of acute renal failure. Acute renal failure during the perioperative period can mainly be explained by iatrogenic, hemodynamic or surgical causes and can result in an increased morbi-mortality. Prevention of this complication requires hemodynamic optimization (venous return, cardiac output, vascular resistance), discontinuation of nephrotoxic drugs but also knowledge of the different steps of the surgery to avoid further degradation of renal perfusion. Diuretics do not prevent acute renal failure and may even push it forward especially during the perioperative period when venous retourn is already reduced. Edema or weight gain following surgery are not correlated with the vascular compartment volume, much less with renal perfusion. Treatment of perioperative acute renal failure is similar to other acute renal failure. Renal replacement therapy must be mastered to prevent any additional risk of hemodynamic instability or hydro-electrolytic imbalance.

Pharmacological strategies to prevent contrast-induced acute kidney injury

Contrast-induced acute kidney injury (CI-AKI) is the most common iatrogenic cause of acute kidney injury after intravenous contrast media administration. In general, the incidence of CI-AKI is low in patients with normal renal function. However, the rate is remarkably elevated in patients with preexisting chronic kidney disease, diabetes mellitus, old age, high volume of contrast agent, congestive heart failure, hypotension, anemia, use of nephrotoxic drug, and volume depletion. Consequently, CI-AKI particularly in high risk patients contributes to extended hospitalizations and increases long-term morbidity and mortality. The pathogenesis of CI-AKI involves at least three mechanisms; contrast agents induce renal vasoconstriction, increase of oxygen free radicals through oxidative stress, and direct tubular toxicity. Several strategies to prevent CI-AKI have been evaluated in experimental studies and clinical trials. At present, intravascular volume expansion with either isotonic saline or sodium bicarbonate solutions has provided more consistent positive results and was recommended in the prevention of CI-AKI. However, the proportion of patients with risk still develops CI-AKI. This review critically evaluated the current evidence for pharmacological strategies to prevent CI-AKI in patients with a risk of developing CI-AKI.

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

Contrast-induced nephropathy (CIN) is a well-known adverse event of therapeutic and diagnostic procedures requiring the administration of contrast medium (CM). The lack of a universal CIN definition and glomerular filtration rate markers that vary have resulted in a variety of reported incidences. The development of CIN is associated with an increase in the length of hospital stay and the risk of death. Preexisting renal dysfunction, age, diabetes, congestive heart failure and the volume of CM administered are all associated with a risk for developing CIN. The literature suggests the use of low-osmolarity CM and supports volume supplementation before administration. Moreover, other strategies to avoid CIN, including treatment with N-acetylcysteine and sodium bicarbonate have variable levels of evidence. This review examines the main components of the pathogenesis and risk factors of CIN and possible preventive measures and therapies.

Role of reactive oxygen species in pathogenesis of radiocontrast-induced nephropathy

In vitro and in vivo studies have demonstrated enhanced hypoxia and formation of reactive oxygen species (ROS) in the kidney following the administration of iodinated contrast media, which play a relevant role in the development of contrast media-induced nephropathy. Many studies indeed support this possibility, suggesting a protective effect of ROS scavenging or reduced ROS formation with the administration of N-acetylcysteine and bicarbonate infusion, respectively. Furthermore, most risk factors, predisposing to contrast-induced nephropathy, are prone to enhanced renal parenchymal hypoxia and ROS formation. In this review, the association of renal hypoxia and ROS-mediated injury is outlined. Generated during contrast-induced renal parenchymal hypoxia, ROS may exert direct tubular and vascular endothelial injury and might further intensify renal parenchymal hypoxia by virtue of endothelial dysfunction and dysregulation of tubular transport. Preventive strategies conceivably should include inhibition of ROS generation or ROS scavenging.

Contrast-induced nephropathy: pathophysiology and preventive strategies

Contrast-induced nephropathy is the third most common cause of hospital-acquired renal failure, after decreased renal perfusion and nephrotoxic medications. Identification of patients at risk and implementation of preventive strategies can decrease the incidence of this nephropathy. Prevention strategies focus on counteracting vasoconstriction, enhancing blood flow through the nephron, and providing protection against injury by oxygen free radicals. Knowledge of the adverse effects associated with infusion of contrast media, identification of patients at risk for contrast-induced nephropathy, and application of evidence-based prevention strategies allow nurses to assist in the prevention of contrast-induced nephropathy.