N-acetylcysteine versus fenoldopam mesylate to prevent contrast agent-associated nephrotoxicity

Contrast removal from coronary sinus for prevention of contrast-induced nephropathy: a review

The occurrence of contrast-induced-nephropathy (CIN) is related to the amount of contrast administration. Any removal of contrast from systemic circulation before reaching the kidneys might be beneficial using a device that removes contrast from a coronary sinus (CS). This manuscript aims to review the available literature regarding contrast removal from CS during coronary angiography or intervention for the prevention of CIN.

Fenoldopam Mesylate: A Narrative Review of Its Use in Acute Kidney Injury

Background:

Fenoldopam mesylate is a selective agonist of DA-1 receptors. It is currently used for the in-hospital treatment of severe hypertension. DA-1 receptors have high density in renal pa-renchyma and for this reason, a possible reno-protective role of Fenoldopam mesylate was investigated.

Methods:

We examined all studies regarding the role of Fenoldopam mesylate in Acute Kidney Injury (AKI); particularly, those involving post-surgical patients, intensive care unit patients and contrast-induced nephropathy.

Results:

Fenoldopam mesylate was found to be effective in reducing the onset of postoperative AKI, when used before the development of the kidney damage. Positive results were also obtained in the management of intensive care unit patients with AKI, although the clinical studies investigated were few and conducted on small samples.

Conclusion:

Conflicting results were achieved in contrast-induced nephropathy.

Effectiveness of contrast-associated acute kidney injury prevention methods; a systematic review and network meta-analysis

BACKGROUND

Different methods to prevent contrast-associated acute kidney injury (CA-AKI) have been proposed in recent years. We performed a mixed treatment comparison to evaluate and rank suggested interventions.

METHODS

A comprehensive Systematic review and a Bayesian network meta-analysis of randomised controlled trials was completed. Results were tabulated and graphically represented using a network diagram; forest plots and league tables were shown to rank treatments by the surface under the cumulative ranking curve (SUCRA). A stacked bar chart rankogram was generated. We performed main analysis with 200 RCTs and three analyses according to contrast media and high or normal baseline renal profile that includes 173, 112 & 60 RCTs respectively.

RESULTS

We have included 200 trials with 42,273 patients and 44 interventions. The primary outcome was CI-AKI, defined as ≥25% relative increase or ≥ 0.5 mg/dl increase from baseline creatinine one to 5 days post contrast exposure. The top ranked interventions through different analyses were Allopurinol, Prostaglandin E1 (PGE1) & Oxygen (0.9647, 0.7809 & 0.7527 in the main analysis). Comparatively, reference treatment intravenous hydration was ranked lower but better than Placebo (0.3124 VS 0.2694 in the main analysis).

CONCLUSION

Multiple CA-AKI preventive interventions have been tested in RCTs. This network evaluates data for all the explored options. The results suggest that some options (particularly allopurinol, PGE1 & Oxygen) deserve further evaluation in a larger well-designed RCTs.

Contrast media-induced nephropathy: how has Italy contributed in the past 30 years? A systematic review

Background and objective

The use of contrast media in Italy has exponentially increased in the past 3 decades. However, it is unknown whether there has been an increase in clinical research evaluating the risks associated with contrast media usage, especially regarding contrast-induced nephropathy. To fill this gap in knowledge, we performed a systematic review.

Study eligibility criteria

Meta-analyses, observational studies, and clinical trials assessing contrast media-induced nephropathy as the safety outcome, in which at least one author was affiliated with an Italian university/health care structure, were eligble.

Data sources

Ovid MEDLINE, Ovid Embase, Cochrane Methodology Register, and Web of Science were screened.

Participants

Men and women exposed to contrast media.

Results

In total, 60 original articles were retrieved with an incremental trend between 1990 and 2017. Cohort studies were the most common study design represented. In total, 45 of 60 (75.0%) studies were monocenter studies and 41 of 60 (68.3%) received no funding. In all, 91.7% of studies disclosed no conflicts of interest and 81.7% had no external collaboration. Most of the studies provided a level of evidence of III-2 (32/60; 53.3%) and II (23/60; 38.3%). In total, 50 of 60 studies (83.3%) were published in a scientific journal ranked in the first quartile of their subject area.

Conclusion

There was an increased number of studies evaluating contrast-induced nephropathy in Italy during the last three decades. These studies covered procedures to prevent contrast-induced nephropathy or aimed to identify risk factors, biomarkers, and scores, and their related prognosis.

Renal protection in cardiovascular surgery

Acute kidney injury (AKI) is one of the most relevant complications after major surgery and is a predictor of mortality. In Western countries, patients at risk of developing AKI are mainly those undergoing cardiovascular surgical procedures. In this category of patients, AKI depends on a multifactorial etiology, including low ejection fraction, use of contrast media, hemodynamic instability, cardiopulmonary bypass, and bleeding. Despite a growing body of literature, the treatment of renal failure remains mainly supportive (e.g. hemodynamic stability, fluid management, and avoidance of further damage); therefore, the management of patients at risk of AKI should aim at prevention of renal damage. Thus, the present narrative review analyzes the pathophysiology underlying AKI (specifically in high-risk patients), the preoperative risk factors that predispose to renal damage, early biomarkers related to AKI, and the strategies employed for perioperative renal protection. The most recent scientific evidence has been considered, and whenever conflicting data were encountered possible suggestions are provided.

Renal-related adverse effects of intravenous contrast media in computed tomography

Renal-related adverse effects of intravascular contrast media (CM) include contrast-induced nephropathy in computed tomography and angiography. While large retrospective studies have been published, the exact pathogenesis of this condition is still unknown. We review the main international guidelines, including the American College of Radiology white paper and the guidelines of European Society of Urogenital Radiology, Royal College of Radiologists and Canadian Association of Radiologists, as well as their references, regarding this subject. We present a simplified, concise approach to renal-related adverse effects of CM, taking into consideration the basis for each recommendation in these published guidelines. This will allow the reader to better understand the rationale behind appropriate patient preparation for cross-sectional imaging.

Fenoldopam for the prevention of contrast-induced nephropathy (CIN)-do we need more trials? A meta-analysis

We conducted a pooled analysis of clinical trials comparing intravenous Fenoldopam (FP) with Saline/Placebo/N-acetyl cysteine (NAC) for the prevention of contrast-induced nephropathy (CIN). Five studies were eligible. Quantitative analyses were done with Review Manager (RevMan version 5.2.). A total of 85 out of 353 patients in Fenoldopam group while 73 among 366 in the control group were affected due to CIN. The risk ratio for the development of CIN in the Fenoldopam group was 1.19 compared to the control group. This was not statistically significant. Fenoldopam is no better than Placebo/Saline or NAC in preventing CIN, but more studies are required.

Intravenous magnesium sulfate: new method in prevention of contrast-induced nephropathy in primary percutaneous coronary intervention

BACKGROUND

Contrast-induced acute kidney injury (CI-AKI) is an adverse consequence of percutaneous coronary interventions which results in significant morbidity and mortality and adds to the costs of diagnostic and interventional cardiology procedures. Various pathophysiological mechanisms have been proposed for CI-AKI and various agents tested for its prevention. There is currently a general agreement that adequate pre-procedural hydration constitutes the cornerstone of prevention, yet there are reports of the use of some other agents with various efficacies. We prospectively tested IV magnesium sulfate (Mg) for CI-AKI prevention.

METHOD AND DESIGN

This study is a prospective, randomized, open-labeled, single-center clinical trial. We randomly assigned 122 consecutive patients to two groups. The first group was the control group with routine treatment (n = 64), and second group was the study group with routine treatment plus IV magnesium sulfate 1 g just before the procedure (n = 62). Serum creatinine was measured before the procedure and 2 days after the procedure. The primary end point was the occurrence of CI-AKI within 48 h. CI-AKI was defined as 0.5 mg/dl or more increase in serum creatinine or 25% or more increase above baseline serum creatinine. There was no difference in definition if both of these parameters were present.

RESULTS

The control and study groups were comparable in the overall predicted risk of CI-AKI. Also, the type and volume of the contrast were not significantly different between the two groups. Following angioplasty, CI-AKI occurred in 17 (26.6%) patients in the control group and nine (14.5%) patients in the study group; there was a significant reduction in CI-AKI in the study group (P = 0.01). Additionally, there was no mortality or a need for hemodialysis in either group.

CONCLUSION

In primary PCI patients, the prophylactic use of intravenous Mg can be recommended to be added to traditional hydration for CI-AKI prevention.

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.

Contrast-induced nephropathy in aged critically ill patients

Background. Aging is associated with renal structural changes and functional decline. The attributable risk for renal dysfunction from radiocontrast agents in critically ill older patients has not been well established. Methods. In this prospective study, we assessed the incidence of contrast-induced nephropathy (CIN) in critically ill patients with stable renal function who underwent computed tomography with intravenous contrast media. Patients were categorized into two age groups: <65 (YG) or ≥65 years old (OG). CIN was defined as 25% or greater increase from baseline of serum creatinine or as an absolute increase by 0.5 mg/dL until the 5th day after the infusion of contrast agent. We also evaluated the alterations in oxidative stress by assessing serum 8-isoprostane. Results. CIN occurred in 5 of 13 OG patients (38.46%) whereas no YG patient presented CIN (P = 0.015). Serum creatinine kinetics in older patients demonstrated a rise over five days following contrast infusion time while a decline was observed in the YG (P = 0.005). Conclusions. Older critically ill patients are more prone to develop renal dysfunction after the intravenous infusion of contrast agent in relation to their younger counterparts.

Acetylcysteine for the prevention of renal outcomes in patients with diabetes mellitus undergoing coronary and peripheral vascular angiography: a substudy of the acetylcysteine for contrast-induced nephropathy trial

BACKGROUND

Diabetes mellitus represents an independent risk factor for contrast-induced acute kidney injury. We report the results of a prespecified substudy of patients with diabetes mellitus included in the Acetylcysteine for Contrast-Induced Nephropathy Trial (ACT), the largest randomized study evaluating the effects of acetylcysteine for the prevention of contrast-induced acute kidney injury conducted to date.

METHODS AND RESULTS

From the 2308 patients included in the ACT, 1395 had diabetes mellitus and were considered for the present analysis. The study drugs (acetylcysteine 1200 mg or matching placebo) were administered orally twice daily for 2 doses before and 2 doses after the procedure. The allocation was concealed (central Web-based randomization). Participants, healthcare staff, data collectors, and outcome assessors were blinded. All analysis followed the intention-to-treat principle. The incidence of contrast-induced acute kidney injury (primary end point) was 13.8% in the acetylcysteine group and 14.7% in the control group (relative risk 0.93; 95% confidence interval, 0.69-1.26; P=0.64). A combined end point of death or need for dialysis at 30 days was also similar in both the groups (2.2% and 2.1%, respectively; hazard ratio, 1.07; 95% confidence interval, 0.52-2.19; P=0.86).

CONCLUSIONS

In this subanalysis, acetylcysteine did not reduce the risk of contrast-induced acute kidney injury or other clinically relevant outcomes in patients with diabetes mellitus undergoing coronary and peripheral vascular angiography.

CLINICAL TRIAL REGISTRATION

URL: http://www.clinicaltrials.gov. Unique identifier: NCT00736866.

The Role of N--Acetylcysteine in the Prevention of Contrast-Induced Nephropathy in Patients Undergoing Peripheral Angiography

Contrast-induced nephropathy (CIN) is a leading cause of hospital-acquired acute kidney injury (AKI). N-acetylcysteine (NAC) was proposed as an effective preventative measure. As data in relation to the use of NAC for the prevention of CIN in peripheral angiography are lacking, a systematic review and meta-analysis were undertaken. A comprehensive search for the published and unpublished data was performed. Data were extracted from the eligible studies. Pooled odds ratios (ORs) were used to calculate the effect of NAC on CIN incidence. Pooled effect size estimates were used to calculate the effect of NAC on serum creatinine (SCr) postcontrast. Our results showed that NAC did not reduce CIN incidence (pooled OR 1.05; 95% confidence interval [CI] 0.38-2.88; P = .92) or the mean SCr levels (pooled weighted mean difference, 4.38; 95% CI 10.4-1.65; P = .15). In conclusion, insufficient evidence exists to recommend NAC for the prevention of CIN in patients undergoing peripheral angiography.

Role of contrast media on oxidative stress, Ca(2+) signaling and apoptosis in kidney

Contrast media (CM)-induced nephropathy is a common cause of iatrogenic acute renal failure. The aim of the present review was to discuss the mechanisms and risk factors of CM, to summarize the controlled studies evaluating measures for prevention and to conclude with evidence-based strategies for prevention. A review of the relevant literature and results from recent clinical studies as well as critical analyses of published systematic reviews used MEDLINE and the Science Citation Index. The cytotoxicity induced by CM leads to apoptosis and death of endothelial and tubular cells and may be initiated by cell membrane damage together with reactive oxygen species (ROS) and inflammation. Cell damage may be aggravated by factors such as tissue hypoxia, properties of individual CM such as ionic strength, high osmolarity and/or viscosity. Clinical studies indeed support this possibility, suggesting a protective effect of ROS scavenging with the administration of N-acetylcysteine, ascorbic acid erdosteine, glutathione and bicarbonate infusion. The interaction between extracellular Ca(2+), which plays a central role in intercellular contacts and production of ROS, and the in vitro toxicity of CM was also reviewed. The current review addresses the role of oxidative stress in the pathogenesis of CM in the kidney as well as current and potential novel treatment modalities for the prevention of neutrophil activation and CM-induced kidney degeneration in patients. ROS production through CM-induced renal hypoxia may exert direct tubular and vascular endothelial injury. Preventive strategies via antioxidant supplementation include inhibition of ROS generation or scavenging.

Comparison of serum creatinine and cystatin C for early diagnosis of contrast-induced nephropathy after coronary angiography and interventions

BACKGROUND

The diagnostic accuracy of serum creatinine and cystatin C (Cys) as early predictors of contrast-induced nephropathy (CIN) has been debated. We investigated the diagnostic sensitivities, diagnostic specificities, and variations from baseline for serum creatinine and Cys in CIN.

METHODS

We prospectively evaluated 166 patients at risk for CIN at baseline, and at 12, 24, and 48 h after exposure to contrast media. CIN occurred in 30 patients (18%). Changes (Δ) compared to baseline in serum creatinine and Cys were evaluated at the predefined time points. ROC curve analysis was performed for the Δ 12-h basal serum creatinine and Cys.

RESULTS

The Δ serum creatinine at 12 h from baseline was the earliest predictor of CIN [area under the ROC curve (AUC) = 0.80; P < 0.001]. The Δ serum creatinine 15% variation [0.15 mg/dL (13.2 μmol/L)] yielded 43% diagnostic sensitivity and 93% diagnostic specificity. The ΔCys at 12 h from baseline performed significantly worse than serum creatinine (AUC = 0.48; P = 0.74).

CONCLUSIONS

Variations from the serum creatinine baseline offer better diagnostic accuracy for predicting CIN at an earlier stage than similar variations in Cys. An additional diagnostic value of Cys over the determination of serum creatinine in the setting of CIN was not observed.

Efficacy of pentoxifylline in prevention of contrast-induced nephropathy in angioplasty patients

BACKGROUND

Contrast-induced nephropathy (CIN) is an adverse consequence of contrast media use that results in significant morbidity and mortality and adds significant costs to diagnostic and interventional cardiology procedures. Various pathophysiological mechanisms have been proposed for CIN and various agents have been tested for its prevention. There is currently a general agreement that adequate pre-procedure hydration constitutes the cornerstone of prevention, yet there are reports of the use of some other agents with various efficacies. We prospectively tested pentoxifylline (PTX), an antioxidant, anti-inflammatory drug, for CIN prevention in patients undergoing coronary angioplasty.

MATERIALS AND METHODS

In this prospective, randomized, single-blind, single-center clinical trial, 286 consecutive patients were randomly assigned to the control group (n = 146), with routine treatment and no PTX, or the study group (n = 140), with routine treatment and PTX, 400 mg/tid from 24 h before to 24 h after coronary angioplasty. Serum creatinine was measured before and 2 days after the procedure. The primary end point was the occurrence of CIN within 48 h.

RESULTS

The control and PTX groups were comparable in the overall predicted risk of CIN. Also, the type and volume of the contrast agent were not significantly different between the two groups. Following angioplasty, CIN occurred in 20 (13.69%) patients in the control group and in 12 (8.5%) patients in the study group; the difference was not statistically significant (P = 0.17). Additionally, there was no mortality and need for hemodialysis in either group.

CONCLUSION

In angioplasty patients, the prophylactic oral use of PTX could be recommended for CIN prevention, although no statistically significant protective effect was documented.

Contrast induced nephropathy: updated ESUR Contrast Media Safety Committee guidelines

PURPOSE

The Contrast Media Safety Committee (CMSC) of the European Society of Urogenital Radiology (ESUR) has updated its 1999 guidelines on contrast medium-induced nephropathy (CIN).

AREAS COVERED

Topics reviewed include the definition of CIN, the choice of contrast medium, the prophylactic measures used to reduce the incidence of CIN, and the management of patients receiving metformin. Key Points • Definition, risk factors and prevention of contrast medium induced nephropathy are reviewed. • CIN risk is lower with intravenous than intra-arterial iodinated contrast medium. • eGFR of 45 ml/min/1.73 m (2) is CIN risk threshold for intravenous contrast medium. • Hydration with either saline or sodium bicarbonate reduces CIN incidence. • Patients with eGFR ≥ 60 ml/min/1.73 m (2) receiving contrast medium can continue metformin normally.

Contrast induced nephropathy in urology

Intravenous contrast agents have a distinct role in urological imaging: to study precise anatomical delineation, vascularity, and to assess the function of the renal unit. Contrast induced nephropathy (CIN) is a known adverse effect of intravenous contrast administration. The literature on incidence, pathophysiology, clinical features, and current preventive strategies available for CIN relevant to urologists was reviewed. A search of the PubMed database was done using the keywords nephropathy and media, prevention and control or prevention Contrast media (explode), all adverse effects, and kidney diseases (explode). An online search of the EMBASE database for the time ranging from 1977 to February 2009 was performed using the keywords ionic contrast medium, adverse drug reaction, major or controlled clinical study, human, nephrotoxicity, and kidney disease. Current publications and data most relevant to urologists were examined. CIN was the third most common cause of hospital-acquired renal failure. The incidence is less common with intravenous contrast administration as compared with intra-arterial administration. The pathogenesis of contrast mediated nephropathy is due to a combination of toxic injury to renal tubules and medullary ischemic injury mediated by reactive oxygen species. CIN most commonly manifests as a nonoliguric and asymptomatic transient decline in renal function. Patients who developed CIN were found to have increased mortality, longer hospital stay, and complicated clinical course. An overview of risk factors and risk prediction score for prognostication of CIN are elaborated. Preventive strategies including choice of contrast agents, maximum tolerated dose, role of hydration, hydration regime, etc. are discussed. The role of N- acetyl cysteine, Theophylline, Fenoldapam, Endothelin receptor antagonists, iloprost, atrial natriuretic peptide, and newer therapies such as targeted renal therapy (TRT) are discussed. A working algorithm based on current evidence is proposed. No current treatment can reverse or ameliorate CIN once it occurs, but prophylaxis is possible.

Early creatinine shifts predict contrast-induced nephropathy and persistent renal damage after angiography

PURPOSE

The purpose of this study was to evaluate incidence and predictors of contrast-induced nephropathy after coronary angiography and interventions, and to assess renal function at 30 days. The prognostic value of any early shift of serum creatinine compared with baseline was investigated; such measurement, being a delta, is largely independent of creatinine variations.

METHODS

There were 216 patients at risk for contrast-induced nephropathy prospectively evaluated at baseline and at 12, 24, and 48 hours after exposure to contrast media, and 190 (88%) evaluated 1 month after discharge.

RESULTS

Contrast-induced nephropathy occurred in 39 patients (18%), and 30-day renal damage was detected in 15 (7%). Contrast media/kg volume predicted contrast-induced nephropathy (P=.002), and percentage change of creatinine 12 hours from baseline was significantly higher in patients with nephropathy (P <.001). At multivariate analysis, percentage change of creatinine 12 hour-basal was the best predictor of nephropathy (P <.001). A 5% increase of its value yielded 75% sensitivity and 72% specificity (area under the curve 0.80; odds ratio 7.37; 95% confidence interval, 3.34-16.23) for early contrast-induced nephropathy detection. Furthermore, it strongly correlated with the development of renal impairment at 30 days (P=.002; sensitivity 87%, specificity 70%; area under the curve 0.85; odds ratio 13.29; 95% confidence interval, 2.91-60.64).

CONCLUSION

Minimal elevations of serum creatinine at 12 hours are highly predictive of contrast-induced nephropathy and 30-day renal damage after exposure to contrast media.

Fenoldopam use in a burn intensive care unit: a retrospective study

BACKGROUND

Fenoldopam mesylate is a highly selective dopamine-1 receptor agonist approved for the treatment of hypertensive emergencies that may have a role at low doses in preserving renal function in those at high risk for or with acute kidney injury (AKI). There is no data on low-dose fenoldopam in the burn population. The purpose of our study was to describe our use of low-dose fenoldopam (0.03-0.09 mug/kg/min) infusion in critically ill burn patients with AKI.

METHODS

We performed a retrospective analysis of consecutive patients admitted to our burn intensive care unit (BICU) with severe burns from November 2005 through September 2008 who received low-dose fenoldopam. Data obtained included systolic blood pressure, serum creatinine, vasoactive medication use, urine output, and intravenous fluid. Patients on concomitant continuous renal replacement therapy were excluded. Modified inotrope score and vasopressor dependency index were calculated. One-way analysis of variance with repeated measures, Wilcoxson signed rank, and chi-square tests were used. Differences were deemed significant at p < 0.05.

RESULTS

Seventy-seven patients were treated with low-dose fenoldopam out of 758 BICU admissions (10%). Twenty (26%) were AKI network (AKIN) stage 1, 14 (18%) were AKIN stage 2, 42 (55%) were AKIN stage 3, and 1 (1%) was AKIN stage 0. Serum creatinine improved over the first 24 hours and continued to improve through 48 hours (p < 0.05). There was an increase in systolic blood pressure in the first 24 hours that was sustained through 48 hours after initiation of fenoldopam (p < 0.05). Urine output increased after initiation of fenoldopam without an increase in intravenous fluid requirement (p < 0.05; p = NS). Modified inotrope score and vasopressor dependency index both decreased over 48 hours (p < 0.0001; p = 0.0012).

CONCLUSIONS

These findings suggest that renal function was preserved and that urine output improved without a decrease in systolic blood pressure, increase in vasoactive medication use, or an increase in resuscitation requirement in patients treated with low-dose fenoldopam. A randomized controlled trial is required to establish the efficacy of low-dose fenoldopam in critically ill burn patients with AKI.

Contrast-induced acute kidney injury in patients with renal dysfunction undergoing a coronary procedure and receiving non-ionic low-osmolar versus iso-osmolar contrast media

BACKGROUND

Although the superiority of low-osmolar over high-osmolar contrast agents in prevention of contrast-induced acute kidney injury (CI-AKI) is generally accepted, the relative nephrotoxicity of iso-osmolar over low-osmolar agents has not yet clearly defined. We examined the incidence of CI-AKI according to the type of contrast agent used in a randomized study of ascorbic acid for CI-AKI prevention.

METHODS

A total of 222 patients with baseline serum creatinine >or=1.2 mg/dL who were undergoing a coronary procedure and who were randomized to receive ascorbic acid or placebo were evaluated. The iso-osmolar agent iodixanol was used in 144 patients, whereas low-osmolar non-ionic agents were used in 78 patients (iomeprol, n = 40; iobitridol, n = 30; iopentol, n = 8). CI-AKI was defined by an absolute serum creatinine increase of >or=0.5 mg/dL or a relative increase of >or=25% measured 2 to 5 days after the procedure.

RESULTS

The groups of patients who received iso-osmolar and low-osmolar non-ionic agents were well balanced in terms of demographic, clinical, and procedural characteristics. The overall CI-AKI incidence was 14.6% for the iso-osmolar iodixanol versus 14.1% for the combined low-osmolar non-ionic agents (iomeprol, 10%; iobitridol, 10%; iopentol, 50%). For iodixanol, the incidence of CI-AKI was 7.4% for patients randomized to receive ascorbic acid and 21.6% for placebo (P = 0.02). The corresponding incidences for the low-osmolar non-ionic agents were 9.1% and 20.6%, respectively (P = 0.19).

CONCLUSION

No differences in CI-AKI incidence were apparent among patients receiving non-ionic iso-osmolar iodixanol and non-ionic low-osmolar contrast agents. The preventative effect of ascorbic acid was also similar.

Risk Factors and Therapy Strategies for Contrast-Induced Nephropathy

Contrast-induced nephropathy (CIN) is associated with increased morbidity and mortality, as well as increased costs for medical care, particularly in patients with diabetes mellitus and chronic renal failure. A key step to safer CIN is to identify patients at risk and applying proven preventive interventions. Extracellular volume expansion, minimizing the dose of contrast media, using low-osmolar non-ionic contrast media, stopping the intake of nephrotoxic drugs, and avoiding short intervals between procedures have all been shown to be effective in reducing CIN. The aim of the present review is to summarize the knowledge about the risk factors and prophylactic treatments of CIN.

Renal Insufficiency Following Radiocontrast Exposure Trial (REINFORCE): a randomized comparison of sodium bicarbonate versus sodium chloride hydration for the prevention of contrast-induced nephropathy

INTRODUCTION

For the prevention of contrast-induced nephropathy (CIN) after coronary angiography, hydration by 0.9% sodium chloride solution and N-acetylcysteine is currently recommended. However, it is unclear whether volume supplementation with sodium bicarbonate is better than with sodium chloride when used in conjunction with nonionic, low-osmolar iopamidol. The aim of this study was to analyze and compare the effects of sodium bicarbonate and sodium chloride on renal function in 145 patients exposed to nonionic iso-osmolar contrast medium iodixanol in a randomized study.

PATIENTS AND METHODS

Renal Insufficiency Following Radiocontrast Exposure is a prospective, randomized, single-center, double-blinded trial of 145 patients (age 72.6+/-6.7 years) with elevated baseline serum creatinine levels (mean 132.6+/-29.3 micromol/l). Eligible patients were randomized to either a 154 mEq/l infusion of sodium bicarbonate (n=71, group I) or sodium chloride 0.9% solution (n=74, group II). The primary endpoint was serum creatinine elevation beyond 25% or 44 micromol/l on the first or second day following exposure to the contrast medium. Serum creatinine, serum cystatin C, plasma viscosity, urinary enzymes alanine aminopeptidase and N-acetyl-beta-D-glucosaminidase, and alpha1-microglobulin were measured at baseline and on days 1 and 2 after contrast medium administration.

RESULTS

An overall proportion of five CIN (3.4%) was observed with equal distribution among the groups (4.2% in sodium bicarbonate group vs. 2.7% in sodium chloride group; P=0.614). Parameters of renal function demonstrated no differences between the two hydration regimens on day 1 after angiography; even on day 2 most parameters were similar in groups I and II.

CONCLUSION

Renal Insufficiency Following Radiocontrast Exposure demonstrates a homogeneously low rate of CIN after exposure to nonionic, iso-osmolar iodixanol regardless of the use of either bicarbonate sodium or sodium chloride solution for volume supplementation. Low-toxicity contrast media and any hydration may offset potential antioxidant effects of sodium bicarbonate.

The patient with acute kidney injury

During the past half decade there has been a paradigm shift in the view of acute kidney disease that has resulted in a change in nomenclature from the older term, "acute renal failure," to "acute kidney injury" (AKI). This article reviews the new criteria for diagnosis and staging of AKI and summarizes the current understanding of the many causes of AKI and the approach to diagnosis and management.

Contrast-induced nephropathy in patients with chronic kidney disease undergoing computed tomography: a double-blind comparison of iodixanol and iopamidol

BACKGROUND

Based on a single clinical trial, it has been suggested that the contrast agent iodixanol, which is isotonic to human plasma, may be less nephrotoxic than other nonionic contrast agents in renally impaired patients after intra-arterial injection. We compared the effects on renal function of iopamidol-370 injection (796 mOsm/kg) and iodixanol-320 (290 mOsm/kg) in patients with chronic kidney disease undergoing contrast-enhanced multidetector computed tomography (CE-MDCT) examinations using a multicenter, double-blind, randomized, parallel-group design.

METHODS

A total of 166 patients with stable moderate-to-severe chronic kidney disease (screening and baseline serum creatinine, SCr, > or =1.5 mg/dL and/or creatinine clearance, CrCl, < or =60 mL/min) who were undergoing CE-MDCT of the liver or peripheral arteries were randomized to receive equi-iodine IV doses (40 gI) of either iopamidol-370 (370 mgI/mL) or iodixanol-320 (320 mgI/mL) at 4 mL/s. SCr and CrCl were obtained at screening, baseline, and at 48-72 +/- 6 hours after dose (mean, 57.4 hours). Contrast-induced nephropathy (CIN) was defined as an absolute increase > or =0.5 mg/dL (44.2 micromol/L) and/or a relative increase in SCr > or =25% from baseline.

RESULTS

A total of 153 patients were included in the final analysis (13 patients excluded because of lack of follow-up, hemodialysis to remove contrast, average daily CrCl variation >1% at screening). The 2 study groups were comparable with regard to age, gender distribution, the presence of diabetes, concomitant medications, hydration, and contrast dose. Mean predose SCr was 1.6 +/- 0.4 mg/dL in both groups (P = 0.9). An absolute increase > or =0.5 mg/dL (44.2 micromol/L) in SCr was observed in none of the patients receiving iopamidol-370 and in 2.6% (2/76) of patients receiving iodixanol-320 (95% confidence interval -6.2, 1.0, P = 0.2). A relative increase > or =25% in SCr occurred in 4% (3/77) of patients receiving iopamidol-370 and in 4% (3/76) of the patients receiving iodixanol-320 (95% confidence interval -6.2, 6.1, P = 1.0).

CONCLUSION

The rate of CIN was similarly low in risk patients after intravenous administration of iopamidol-370 or iodixanol-320 for CE-MDCT.

A meta-analysis of N-acetylcysteine in contrast-induced nephrotoxicity: unsupervised clustering to resolve heterogeneity

BACKGROUND

Meta-analyses of N-acetylcysteine (NAC) for preventing contrast-induced nephrotoxicity (CIN) have led to disparate conclusions. Here we examine and attempt to resolve the heterogeneity evident among these trials.

METHODS

Two reviewers independently extracted and graded the data. Limiting studies to randomized, controlled trials with adequate outcome data yielded 22 reports with 2746 patients.

RESULTS

Significant heterogeneity was detected among these trials (I2 = 37%; p = 0.04). Meta-regression analysis failed to identify significant sources of heterogeneity. A modified L'Abbé plot that substituted groupwise changes in serum creatinine for nephrotoxicity rates, followed by model-based, unsupervised clustering resolved trials into two distinct, significantly different (p < 0.0001) and homogeneous populations (I2 = 0 and p > 0.5, for both). Cluster 1 studies (n = 18; 2445 patients) showed no benefit (relative risk (RR) = 0.87; 95% confidence interval (CI) 0.68-1.12, p = 0.28), while cluster 2 studies (n = 4; 301 patients) indicated that NAC was highly beneficial (RR = 0.15; 95% CI 0.07-0.33, p < 0.0001). Benefit in cluster 2 was unexpectedly associated with NAC-induced decreases in creatinine from baseline (p = 0.07). Cluster 2 studies were relatively early, small and of lower quality compared with cluster 1 studies (p = 0.01 for the three factors combined). Dialysis use across all studies (five control, eight treatment; p = 0.42) did not suggest that NAC is beneficial.

CONCLUSION

This meta-analysis does not support the efficacy of NAC to prevent CIN.

Sodium bicarbonate, N-acetylcysteine, and saline for prevention of radiocontrast-induced nephropathy. A comparison of 3 regimens for protecting contrast-induced nephropathy in patients undergoing coronary procedures. A single-center prospective controlled trial

BACKGROUND

Several protective therapies have been developed to prevent contrast-induced nephropathy (CIN). We aimed to investigate the efficacy of sodium bicarbonate by comparing 2 other regimens, including combination of N-acetylcysteine (NAC) plus sodium chloride and sodium chloride alone, to prevent CIN in patients undergoing cardiovascular procedures.

METHODS

We prospectively enrolled 264 patients who were scheduled for cardiovascular procedures and had a baseline creatinine level >1.2 mg/dL. The patients were assigned 1 of 3 prophylactic regimens: infusion of sodium bicarbonate, sodium chloride, sodium chloride plus oral NAC (600 mg bid). Contrast-induced nephropathy was defined as an increase in serum creatinine level >25% or 0.5 mg/dL after 48 hours.

RESULTS

There were no significant differences among groups regarding baseline demographic properties and nephropathy risk factors. The change in creatinine clearance was significantly better in the sodium bicarbonate group than other 2 groups (P = .007). The incidence of CIN was significantly lower in the sodium bicarbonate group (4.5%) compared with sodium chloride alone (13.6%, P = .036) and tended to be lower than in the combination group (12.5%, P = .059). After adjusting the Mehran nephropathy risk score, the risk of CIN significantly reduced with sodium bicarbonate compared with sodium chloride alone (adjusted risk ratio 0.29, P = .043).

CONCLUSIONS

Hydration with sodium bicarbonate provides better protection against CIN than the sodium chloride infusion does alone. Combination therapy of NAC plus sodium chloride did not offer additional benefit over hydration with sodium chloride alone.

Effects of Acetylcysteine and Probucol on Contrast Medium-induced Depression of Intrinsic Renal Glutathione Peroxidase Activity in Diabetic Rats

BACKGROUND

Antioxidants such as N-acetylcysteine and probucol have been used to protect patients from contrast media-induced nephrotoxicity. The mechanisms underlying these protective effects are not well understood. We hypothesized that acetylcysteine and probucol alter the activity of endogenous antioxidant enzyme activity.

METHODS

Four weeks after induction of diabetes with streptozotocin, diabetic and nondiabetic rats were divided into three groups. Group 1 rats did not receive any antioxidant agents. Group 2 rats were treated with acetylcysteine and group 3 rats with probucol for 1 week before injection of the contrast medium diatrizoate (DTZ).

RESULTS

We found that diabetic rats had higher renal glutathione peroxidase (GPx) activity than normal rats. DTZ suppressed renal GPx activity significantly in both group 1 diabetic and normal rats. Interestingly, renal GPx activity in both diabetic and normal rats pretreated with acetylcysteine or probucol was not inhibited by DTZ. Renal superoxide dismutase (SOD) increased significantly in normal rats after DTZ injection, but not in diabetic rats. Finally, acetylcysteine or probucol did not significantly influence renal SOD.

CONCLUSIONS

These findings suggest that the renal protective effects of acetylcysteine and probucol against contrast-induced oxidative stress and nephrotoxicity may be mediated by altering endogenous GPx activity.

N-acetylcysteine in the prevention of contrast agent-induced nephrotoxicity in patients undergoing computed tomography studies

We compared two chemotherapy regimens for advanced non small-cell lung cancer. The CG regimen consisted of carboplatin (AUC 4 to 5) on day 1 plus gemcitabine (1,000 mg/m(2)) on day 1 and 8, every three weeks, while the CP regimen was carboplatin (AUC 6) on day 1 plus paclitaxel (70 mg/m(2)) on day 1, 8 and 15, every four weeks. There was a total of 62 patients, 23 on the CG regimen and 39 on the CP regimen. In initial treatment, the response rate, time to progression and median survival time in the CG regimen and CP regimens were 40% vs 22%, 124 days vs 67 days, and 422 days vs 328 days, respectively. There was no statistical difference in the outcome. However, the toxicity profile was different in the two regimens. Grade 3/4 neutropenia and thrombocytopenia were frequent in the CG regimen (61% vs 31%, p=0.02, 44% vs 3%, p=0.0002, respectively). Non hematological toxicity including grade 2 alopecia was less in the CG regimen (4% vs 36%, p=0.012). In choosing the chemotherapeutic regimen for non small cell cancer, it is important to consider the toxicity.

Contrast media and nephropathy: findings from systematic analysis and Food and Drug Administration reports of adverse effects

CONTEXT

Recent studies suggest differences in the incidence of contrast-induced nephropathy (CIN) among contrast media (CM).

OBJECTIVE

To determine whether there are significant differences among low-osmolality CM (LOCM) in the incidence of contrast-induced nephropathy (CIN), we reviewed published studies of CIN in renally impaired patients and conducted statistical data mining using databases of adverse events maintained by the U.S. Food and Drug Administration (FDA).

DATA SOURCES

A systematic literature search was performed for prospective, controlled, English language studies published in peer-reviewed journals that reported CIN rates in renally impaired patients after a specific LOCM. Databases searched were EMBASE, MEDLINE, Biosis Previews, Derwent Drug File, Pascal, and SciScearch Cited Ref Sci. For the FDA analysis, we used the SRS and AERS databases.

DATA SELECTION

Twenty-two studies reporting data in 3112 patients with renal impairment met the inclusion criteria. Most studies reported on the use of a pharmacologic intervention to prevent CIN. From the FDA databases, we evaluated 18 adverse event terms associated with renal injury or dysfunction after CM use.

DATA EXTRACTION

Data from 22 studies were entered into a database. A meta-regression analysis using a mixed effect model was performed. CM effect was adjusted by the following covariates: baseline patient characteristics (mean age, gender distribution) and risk factors (prevalence of diabetes mellitus, degree of renal impairment, CM volume), and the use of prophylactic drug treatments. Multiple disproportionality analyses (adjusted odds ratio, adjusted empirical Bayesian estimate, or Bayesian logistic regression) were performed on the FDA databases to estimate associations between 4 CM and 18 AE terms related to CIN.

DATA SYNTHESIS

Systematic analysis of clinical trials suggest the highest incidence of CIN occurs in patients receiving iohexol and the lowest incidence in patients receiving iopamidol, even when corrected for other CIN risk factors. Statistical data mining of FDA data also showed the highest association of CIN for iohexol and the lowest for iopamidol.

CONCLUSIONS

The risk of CIN was higher in patients receiving iohexol compared with patients receiving iopamidol. No significant differences were found comparing iohexol to other LOCMs, including iodixanol.

Management of the critically ill geriatric patient

OBJECTIVE

To review the effect of an aging society on the utilization of critical care services and the physiology of aging as it applies to critical illness and prognosis and management issues in the intensive care unit (ICU).

DATA SOURCE

MEDLINE, Embase, and citation review of relevant primary and review articles.

DATA SYNTHESIS

Elderly patients (age of >65 yrs) currently account for 42-52% of ICU admissions and for almost 60% of all ICU days. Aging is associated with decreased cardiopulmonary and renal reserve and with a high rate of co-morbidities, increasing the risks of the elderly developing progressive organ failure. Elderly ICU patients are at a particularly high risk of developing delirium, which is associated with significant morbidity. Severity of illness and age are the important factors determining ICU survival. Age and functional status before ICU admission are the major determinants of survival at 6 and 12 months after ICU discharge. Age alone should not be used to triage ICU patients; the decision to admit an elderly patient to an ICU should be based on the patients co-morbidities, acuity of illness, prehospital functional status, and preferences with regard to life-sustaining treatment.

CONCLUSIONS

The management of critically ill elderly patients is a complex issue and involves an understanding of the changing demographics of our society and the physiology of aging. The reality of our aging society dictates that we must focus on how to best care for the elderly who develop critical illness.

Strategies to reduce the risk of contrast-induced nephropathy

In view of the clinical importance of contrast-induced nephropathy (CIN), numerous potential risk-reduction strategies have been evaluated. Adequate intravenous volume expansion with isotonic crystalloid (1.0-1.5 mL/kg per hr) for 3-12 hours before the procedure and continued for 6-24 hours afterward can lessen the probability of CIN in patients at risk. There are insufficient data on oral fluids (as opposed to intravenous volume expansion) as a CIN-prevention strategy. No adjunctive medical or mechanical treatment has been proved to be efficacious in reducing risk for CIN. Prophylactic hemodialysis and hemofiltration have not been validated as effective strategies. The CIN Consensus Working Panel considered that, of the pharmacologic agents that have been evaluated, theophylline, 3-hydroxy-3-methylglutaryl coenzyme A reductase inhibitors (statins), ascorbic acid, and prostaglandin E(1) deserve further evaluation. N-acetylcysteine is not consistently effective in reducing the risk for CIN. Fenoldopam, dopamine, calcium channel blockers, atrial natriuretic peptide, and l-arginine have not been shown to be effective. Use of furosemide, mannitol, or an endothelin receptor antagonist is potentially detrimental. Nephrotoxic drugs should be withdrawn before contrast administration in patients at risk for CIN.

Epidemiology and prognostic implications of contrast-induced nephropathy

Contrast-induced nephropathy (CIN), usually defined as an increase in serum creatinine of 0.5 mg/dL (44.2 mumol/L), or a 25% increase from the baseline value 48 hours after the procedure, is a common and potentially serious complication of the use of iodinated contrast media in patients at risk of acute renal injury. It is an important cause of hospital-acquired renal failure, responsible for approximately 11% of cases. CIN may be difficult to distinguish from cholesterol embolization, another cause of postprocedure renal impairment. The reported incidence of CIN varies depending on the patient population studied. The impact of postprocedural renal impairment on clinical outcomes has been evaluated most extensively in patients undergoing percutaneous coronary intervention. CIN is associated with increased mortality both in hospital and at 1 year. A higher incidence of in-hospital and late cardiovascular events, as well as longer hospital stays, has been reported in patients developing CIN. In a small proportion of patients, CIN is severe enough to require dialysis, and these patients have a particularly poor prognosis. Many of the risk markers for CIN are also predictive of a worse prognosis.

Is radiocontrast-induced nephropathy avoidable? The scientific evidence in 2006

Due to the wide use of radiocontrast agents (RCA) in modern radiology and interventional cardiology, the incidence of radiocontrast-induced nephropathy (RCIN) is increasing. The risk factors for RCIN are primarily pre-existing (even mild) renal dysfunction, diabetes mellitus, absolute or relative hypovolemia, nephrotoxic drugs, etc., particularly in elderly patients. The presence of these risk factors seems to be more important than the type of contrast agent used. To date, there are several certainties and controversies in the prevention of RCIN. Hydration with normal saline and/or bicarbonate administration pre-and post-intervention is certainly useful. Though controversial, N-Acetylcysteine administration may be still advisable. Recent investigations showed the benefits of aminophylline/theophylline administration in RCA-induced renal tubular toxicity. Conventional hemodialysis cannot prevent RCIN, but may potentially aggravate renal dysfunction through hemodynamic instability. “High-flux” hemodialysis and hemodiafiltration may contribute efficiently to RCIN prevention, but systematic use of these modern dialysis techniques is limited by high costs and availability. The authors review — in a systematic manner, and in the perspective of evidence-based medicine — the most important data from literature concerning the prevention of RCIN.

Prevention and Treatment of Contrast-Induced Nephropathy

Contrast-induced nephropathy (CIN) is a well-known complication of therapeutic and diagnostic procedures requiring contrast administration and accounts for 10 to 12% of acute renal failure in hospitalized patients. Although the incidence of this complication is relatively low, its consequences can be catastrophic. The development of CIN is associated with increased hospital length of stay, an increased requirement for acute dialysis, and an increased risk of death. Preexisting renal dysfunction, age, diabetes, congestive heart failure, and volume of administered contrast are all associated with a risk of developing CIN. Despite a large number of clinical trials that have evaluated prophylaxis strategies for CIN, only the use of hemofiltration and N-acetylcysteine (NAC) in specific subgroups of patients have been shown to reduce dialysis requirement and mortality in patients undergoing angiographic procedures. In this review we will discuss the epidemiology and the risk factors for CIN and the evidence for commonly employed prophylaxis strategies, and we will provide general recommendations with respect to CIN prevention and management.