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

Prevention of contrast-associated acute kidney injury in an era of increasingly complex interventional procedures

Radiological and interventional cardiology procedures are in continuous expansion, leading to an important increase in the incidence of contrast-associated acute kidney injury (CA-AKI). Although numerous methods of CA-AKI prevention have been studied, at present, there is no consensus on the definition of this entity or on its prevention. In this paper, we aim to provide a critical analysis of the existing data on the epidemiology, pathophysiology, and clinical significance of CA-AKI. Existing and emergent approaches for CA-AKI prevention are also discussed, with a focus on parenteral fluid administration and on the most recent clinical and experimental data. We also emphasize a number of questions that remain to be answered, and we identify hotspots for future research.

Radiographic Contrast Media and the Kidney

AKI is a potential complication of intravascular iodinated contrast exposure. Contrast-associated AKI, which typically manifests as small and transient decrements in kidney function that develop within several days of contrast administration, is associated with serious adverse outcomes, including progressive kidney dysfunction and death. However, a causal link between the small increases in serum creatinine that characteristically occur with contrast-associated AKI and serious adverse outcomes remains unproven. This is important given mounting evidence that clinically indicated, potentially lifesaving radiographic procedures are underutilized in patients with CKD. This has been hypothesized to be related to provider concern about precipitating contrast-associated AKI. Intravascular gadolinium-based contrast, an alternative to iodinated contrast that is administered with magnetic resonance imaging, has also been linked with potential serious adverse events, notably the development of nephrogenic systemic fibrosis in patients with severe impairment in kidney function. Patients hospitalized in the intensive care unit frequently have clinical indications for diagnostic and therapeutic procedures that involve the intravascular administration of contrast media. Accordingly, critical care providers and others treating critically ill patients should possess a sound understanding of the risk factors for and incidence of such outcomes, the ability to perform evidence-based risk-benefit assessments regarding intravascular contrast administration, and knowledge of empirical data on the prevention of these iatrogenic complications.

Trimetazidine reduces contrast-induced nephropathy in patients with renal insufficiency undergoing coronary angiography and angioplasty: A systematic review and meta-analysis (PRISMA)

OBJECTIVES

This systematic review and meta-analysis assesses the utility of trimetazidine (TMZ) to prevent contrast induced nephropathy (CIN) in patients with renal insufficiency undergoing coronary angiography and angioplasty.

MATERIALS AND METHODS

This meta-analysis was formulated and reported according to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines. A search of databases was conducted by 2 researchers independently for clinical trials, comparing hydration plus TMZ vs conventional hydration alone for prevention of CIN through January 2020. All patients had renal insufficiency (defined as GFR < 89 ml/minute/1.73 m2) and the outcome of interest was the incidence of contrast induced acute kidney injury. The odds ratio (OR) was estimated with 95% confidence interval (CI). Heterogeneity was reported with the I2 statistic, using a fixed-effects model, and >50% of I2 was considered to be statistically significant.

RESULTS

Eleven studies, 1611 patients, met the inclusion/exclusion criteria: 797 patients comprised the TMZ plus hydration group and the remaining 814 patients comprised the control (hydration only) group. Heterogeneity was low I2 = 0%, P = .84, and the heterogeneity of each study was also low. The incidence of CIN in the TMZ plus hydration group was 6.6% (53/797), while the incidence of CIN in the control (hydration only) group was 20% (165/814). Pooled analysis of all studies showed TMZ reduced incidence of CIN compared to saline hydration alone (OR risk 0.30, 95% CI 0.21, 0.42, P < .0001).

CONCLUSION

TMZ added to hydration reduces CIN in renal insufficiency patients undergoing coronary angiography.

[ESUR recommendations on the use of contrast media: Practice survey, review and commentary by CJN, FIRN and SFNDT]

Contrast media administration is classically considered to cause or worsen kidney failure. Recent data may moderate this assertion. The European Society of Urogenital Radiology recently published guidelines re-evaluating the precautions before administering contrast media. The present work evaluates the practice of French nephrologists, and provides a commentary on these recommendations based on an updated review of the literature. We conducted survey among French nephrologists, using an electronic questionnaire distributed by the Société Francophone de Néphrologie, Dialyse et Transplantation, the French Intensive care Renal Network and the Club des Jeunes Néphrologues. 266 responses were collected. The European Society of Urogenital Radiology guidelines are poorly known among the panel of nephrologists. Their practices differ from the guidelines by the more frequent and earlier implementation of measures to prevent renal failure post contrast media. In accordance with the guidelines, hydration is prescribed as a first-line preventive measure, mainly with saline and bicarbonate. Inhibitors of the renin-angiotensin-aldosterone system are frequently discontinued before an injection of contrast media, contrary to what is recommended. In conclusion, the European Society of Urogenital Radiology guidelines, which the working group endorses, but which are still too little known and applied in clinical nephrology in France, prompt nephrologists to lift some of the restrictions on the use of PCI as well as on the continuation of ARS inhibitors before injecting PCI.

Kidney and contrast media: Common viewpoint of the French Nephrology societies (SFNDT, FIRN, CJN) and the French Radiological Society (SFR) following ESUR guidelines

Contrast medium administration is classically considered to cause or worsen kidney failure, but recent data may moderate this assertion. The European Society of Urogenital Radiology recently published guidelines re-evaluating the precautions before administering contrast media. Kidney injury does not constitute a contra-indication to the administration of iodinated contrast medium, as long as the benefit-risk ratio justifies it. Intravenous hydration with 0.9% NaCl or 1.4% sodium bicarbonate is the only validated measure for the prevention of post-iodine contrast nephropathy. This is necessary for intravenous or intra-arterial administration of iodinated contrast agent without first renal pass when the glomerular filtration rate is less than 30mL/min/1.73m², for intra-arterial administration of iodinated contrast agent with first renal passage when the glomerular filtration rate is less than 45mL/min/1.73m², or in patients with acute renal failure. The use of iodinated contrast medium should allow the carrying out of relevant examinations based on an analysis of the benefit-risk ratio and the implementation of measures to prevent toxicity when necessary.

The place of hydration using intravenous fluid in patients at risk of developing contrast-associated nephropathy

There has been a significant rise in the incidence of contrast-associated nephropathy caused by administration of contrast media during cardiac interventions. This is one of the major complications of percutaneous coronary interventions, which may proceed to acute renal failure. Risk factors, including pre-existing renal dysfunction, older age and use of high osmolar contrast media, predispose patients to the development of contrast-associated nephropathy. Different risk-reduction strategies have been used to prevent contrast-associated nephropathy, including use of low osmolar contrast media, N-acetylcysteine, alkalisation of tubular fluid with intravenous sodium bicarbonate, and oral and intravenous hydration with isotonic solution. Hydration using intravenous saline is one of the main treatments used to prevent the development of nephropathy in patients receiving contrast media during cardiac interventions. Prehydration, before administering contrast media, seems to be crucial. The results of studies of the relative efficacy of sodium bicarbonate and/or N-acetylcysteine in reducing the development of contrast-associated nephropathy are not consistent and any beneficial effects may depend on the pre-existing state of the kidney. This review discusses hydration of patients who are at risk of developing contrast-associated nephropathy using intravenous fluid.

Contrast-induced acute kidney injury

Although major advancements in the field of cardiology have allowed for an increasing number of patients to undergo minimally invasive imaging and interventional procedures, contrast-induced acute kidney injury (CI-AKI) continues to be a dreaded complication among patients receiving intravascular contrast media. CI-AKI is characterized by progressive decline in kidney function within a few days of contrast medium administration. Physiological changes resulting from the direct nephrotoxic effect of contrast media on tubular epithelial cells and release of vasoactive molecules have been implicated in creating a state of increased oxidative stress and subsequent ischemic renal cell injury. Over the last several years, preventive strategies involving intravenous hydration, pharmaceutical agents and renal replacement therapies have resulted in lower rates of CI-AKI. However, due to the evolving paradigm of diagnostic and therapeutic interventions, several unanswered questions remain. This review highlights the epidemiology, pathogenesis and preventive strategies of CI-AKI.

Hydration Strategies for Preventing Contrast-Induced Acute Kidney Injury: A Systematic Review and Bayesian Network Meta-Analysis

Aims

Many previous studies have examined the effect of different hydration strategies on prevention of contrast-induced acute kidney injury (CI-AKI), but the optimal strategy is unknown. We performed a network meta-analysis (NWM) of these previous studies to identify the optimal strategy.

Methods and Results

Web of Science, PubMed, OVID Medline, and Cochrane Library were searched from their inception dates to September 30, 2018. Randomized controlled trials (RCTs) were selected based on strict inclusion criteria, and a Bayesian NWM was performed using WinBUGS V.1.4.3. We finally analyzed 60 eligible RCTs, which examined 21,293 patients and 2232 CI-AKI events. Compared to intravenous 0.9% sodium chloride (reference), intravenous sodium bicarbonate (OR [95% CI]: 0.74 [0.57, 0.93]), hemodynamic guided hydration (0.41 [0.18, 0.93]), and RenalGuard guided hydration (0.32 [0.14, 0.70]) significantly reduced the occurrence of CI-AKI. Oral hydration and intravenous 0.9% sodium chloride were each noninferior to no hydration in preventing CI-AKI. Intravenous 0.9% sodium chloride, sodium bicarbonate, and hemodynamic guided hydration were each noninferior to oral hydration in preventing CI-AKI. Based on surface under the cumulative ranking curve values, the RenalGuard system was best (0.974) and hemodynamic guided hydration was second best (0.849).

Conclusion

There was substantial evidence to support the use of RenalGuard or hemodynamic guided hydration for preventing CI-AKI in high-risk patients, especially those with chronic kidney disease or cardiac dysfunction.

Dual source abdominal computed tomography: the effect of reduced X-ray tube voltage and intravenous contrast media dosage in patients with reduced renal function

BACKGROUND

X-ray tube voltage (kVp) reduction increases intravenous contrast medium (CM) attenuation at computed tomography (CT), but tube output limits its use in large patients.

PURPOSE

To evaluate the feasibility and image quality of reducing CM dose by low kVp and using dual X-ray source at liver CT.

MATERIAL AND METHODS

Patients with estimated glomerular filtration rate (eGFR) < 45 mL/min (n = 43) aged 60-91 years (75 ± 7.7), weighing 42-114 kg (75 ± 15) were prospectively scanned using a reduced CM dose of 0.25 or 0.3 g iodine (I)/kg with 70 or 80 kVp respectively, using either single-source or dual-source CT depending on patient size. Liver contrast-to-noise ratio (CNR), liver noise, and muscle noise were quantitatively compared with those of 43 consecutive patients aged > 65 years with eGFR > 45 mL/min scanned using a standard abdominal protocol at 120 kVp after receiving 0.5 gI/kg.

RESULTS

There was no statistically significant difference in CNR, liver noise, or muscle noise at reduced CM protocols compared to the standard protocol: CNR was 4.6 (95% CI = 4.2-5.0) vs. 5.0 (95% CI = 4.5-5.5), liver noise was 11.1 (95% CI = 10.7-11.6) vs. 11.0 (95% CI = 10.5-11.6), muscle noise was 11.7 (95% CI = 11.2-12.1) vs. 10.8 (95% CI = 10.1-11.4). The mean SSDE was 70% higher with the reduced CM protocol.

CONCLUSION

CM dosage can be reduced by 40-50% with maintained measured noise and CNR in patients with BMIs of 15-36 kg/m² by lowering the tube voltage and dual-source CT scanning of the liver.

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

Contrast volume to estimated glomerular filtration rate ratio for prediction of contrast-induced acute kidney injury after cardiac catheterization in adults with congenital heart disease

BACKGROUND

Adults with congenital heart disease (ACHD) are vulnerable to contrast-induced acute kidney injury (CI-AKI) after cardiac catheterization. The aim of this study was to identify risk factors for clinically significant CI-AKI and evaluate the predictive value of contrast volume to estimated glomerular filtration rate ratio (V/eGFR) for the risk of CI-AKI following catheterization in the ACHD population.

METHODS

ACHD patients who underwent catheterization at Boston Children's hospital between 1/2011 and 1/2017 were retrospectively analyzed. CI-AKI was defined as an increase in serum creatinine ≥0.3 mg/dL within 48 hr or ≥1.5 times baseline within 7 days of procedure. Controls without CI-AKI were matched for calendar year of catheterization with cases using a 3:1 ratio.

RESULTS

Of 453 catheterizations meeting inclusion criteria, 27 catheterizations (5.9%) were complicated by CI-AKI, with dialysis being used to manage renal dysfunction in five of these events. Older age, male gender, admission prior to catheterization, and V/eGFR ratio were found to be related to risk of CI-AKI. Patients with a V/eGFR ≥ 2.6 had a significantly higher risk of CI-AKI (OR = 6.4; 95% CI = 2.0-20.4; P = 0.002). Survival at 3 years post-catheterization, was significantly shorter for CI-AKI cases compared to controls (49% versus 97%; P < 0.001) even in those with return to baseline renal function prior to discharge (60% versus 97%, P < 0.001).

CONCLUSION

In ACHD patients undergoing cardiac catheterization, a higher V/eGFR ratio is a strong predictor of clinically significant CI-AKI. Development of CI-AKI is a poor prognostic indicator and is associated with decreased survival in this population.

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.

Post-contrast acute kidney injury. Part 2: risk stratification, role of hydration and other prophylactic measures, patients taking metformin and chronic dialysis patients : Recommendations for updated ESUR Contrast Medium Safety Committee guidelines

OBJECTIVES

The Contrast Media Safety Committee (CMSC) of the European Society of Urogenital Radiology (ESUR) has updated its 2011 guidelines on the prevention of post-contrast acute kidney injury (PC-AKI). The results of the literature review and the recommendations based on it, which were used to prepare the new guidelines, are presented in two papers. AREAS COVERED IN PART 2: Topics reviewed include stratification of PC-AKI risk, the need to withdraw nephrotoxic medication, PC-AKI prophylaxis with hydration or drugs, the use of metformin in diabetic patients receiving contrast medium and the need to alter dialysis schedules in patients receiving contrast medium.

KEY POINTS

• In CKD, hydration reduces the PC-AKI risk • Intravenous normal saline and intravenous sodium bicarbonate provide equally effective prophylaxis • No drugs have been consistently shown to reduce the risk of PC-AKI • Stop metformin from the time of contrast medium administration if eGFR < 30 ml/min/1.73 m 2 • Dialysis schedules need not change when intravascular contrast medium is given.

Contrast-Induced Nephropathy: Update on the Use of Crystalloids and Pharmacological Measures

Contrast-induced nephropathy (CIN) is a frequent and severe complication in subjects receiving iodinated contrast media for diagnostic or therapeutic purposes. Several preventive strategies were evaluated in the past. Recent clinical studies and meta-analyses delivered some new aspects on preventive measures used in the past and present. We will discuss all pharmacological and nonpharmacological procedures. Finally, we will suggest individualized recommendations for CIN prevention.

[Vitamin C+sodium bicarbonate versus sodium bicarbonate alone in preventing contrast-induced nephropathy]

INTRODUCTION

Contrast-induced nephropathy (CIN) is a common and severe complication in interventional cardiology.

OBJECTIVE

The aim of our study was to compare the incidence of contrast-induced nephropathy in two accelerated hydration protocols: the first one by the serum bicarbonate and the second combining the serum bicarbonate and oral vitamin C.

METHODS

This is a multicenter prospective, randomized study conducted between October 2012 and May 2013, including 160 patients.

RESULTS

The mean age of our study population was 60.8±9.3 years (36-83 years). The two study groups were comparable in terms of cardiovascular risk factors, concomitant medication, and baseline serum creatinine. The CIN incidence was 6.3% in the vitamin C group and 10% in the control group (P=0.38). No significant difference was observed in terms of CIN incidence between the different subgroups analyzed.

CONCLUSION

According to our study, ascorbic acid administered orally as part of an accelerated hydration protocol does not reduce the incidence of CIN.

Anesthetic considerations for endovascular abdominal aortic aneurysm repair

Aneurysm is defined as a localized and permanent dilatation with an increase in normal diameter by more than 50%. It is more common in males and can affect up to 8% of elderly men. Smoking is the greatest risk factor for abdominal aortic aneurysm (AAA) and other risk factors include hypertension, hyperlipidemia, family history of aneurysms, inflammatory vasculitis, and trauma. Endovascular Aneurysm Repair [EVAR] is a common procedure performed for AAA, because of its minimal invasiveness as compared with open surgical repair. Patients undergoing EVAR have a greater incidence of major co-morbidities and should undergo comprehensive preoperative assessment and optimization within the multidisciplinary settings. In majority of cases, EVAR is extremely well-tolerated. The aim of this article is to outline the Anesthetic considerations related to EVAR.

Strategies Preventing Contrast-Induced Nephropathy After Coronary Angiography: A Comprehensive Meta-Analysis and Systematic Review of 125 Randomized Controlled Trials

This systematic review with meta-analysis sought to determine the strength of evidence for the effects of hydration (sodium bicarbonate [SB] and normal saline [NS]), supplementations ( N-acetylcysteine [NAC] and vitamin C), and some common drugs (adenosine antagonists [AAs], statins, loop diuretics, and angiotensin-converting enzyme inhibitors [ACEIs]) on the incidence of contrast-induced nephropathy (CIN) and requirement for hemodialysis after coronary angiography. After screening, a total of 125 trials that reported outcomes were identified. Pooled analysis indicated beneficial effects of SB versus NS (odds ratio [OR] = 0.73; 95% confidence interval [CI]: 0.56-0.94; P = .01), NAC (OR = 0.79; 95% CI: 0.70-0.88; P = .001), vitamin C (OR = 0.64; 95% CI: 0.45-0.89; P = .01), statins (OR = 0.45; 95% CI: 0.35-0.57; P = .001), AA (OR = 0.28; 95% CI: 0.14-0.47; P = .001), loop diuretics (OR = 0.97; 95% CI: 0.33-2.85; P = .9), and ACEI (OR = 1.06; 95% CI: 0.69-1.61; P = .8). Overall, hydration with SB, use of supplements, such as NAC and vitamin C, and administration of statins and AA should always be considered for the prevention of CIN after coronary angiography.

How Strong Is the Evidence for Sodium Bicarbonate to Prevent Contrast-Induced Acute Kidney Injury After Coronary Angiography and Percutaneous Coronary Intervention?

Hydration with sodium bicarbonate is one of the strategies to prevent contrast-induced acute kidney injury (CI-AKI). The purpose of this study was to determine how strong is the evidence for sodium bicarbonate to prevent CI-AKI after coronary angiography (CAG) and/or percutaneous coronary intervention (PCI).We conducted PubMed, EMBASE, and CENTRAL databases to search for randomized controlled trials (RCTs) comparing the efficacy of sodium bicarbonate with sodium chloride to prevent CI-AKI after CAG and/or PCI. Relative risk (RR), standardized mean difference (SMD), or weighted mean difference (WMD) with 95% confidence intervals (CIs) was calculated. Heterogeneity, publication bias, and study quality were evaluated, sensitivity analyses, cumulative analyses, and subgroup analyses were performed. The risk of random errors was assessed by trial sequential analysis (TSA).Sixteen RCTs (3537 patients) met the eligibility criteria. Hydration with sodium bicarbonate showed significant beneficial effects in preventing CI-AKI (RR 0.67; 95% CI: 0.47-0.96, P = 0.029), decreasing the change in serum creatinine (SCr) (SMD -0.31 95% CI: -0.55 to -0.07, P = 0.011) and estimated glomerular filtration rate (eGFR) (SMD -0.17 95% CI: -0.30 to -0.04, P = 0.013). But no significant differences were observed in the requirement for dialysis (RR 1.11; 95% CI: 0.60-2.07, P = 0.729), mortality (RR 0.71; 95% CI: 0.41-1.21, P = 0.204) and reducing the length of hospital stay (LHS) (WMD -1.47; 95% CI: -4.14 to 1.20, P = 0.279). The result of TSA on incidence of CI-AKI showed the required information size (RIS = 6614) was not reached and cumulative z curve did not cross TSA boundary. The result of TSA on the requirement for dialysis and mortality demonstrated the required information sizes (RIS = 170,510 and 19,516, respectively) were not reached, and the cumulative z-curve did not cross any boundaries.The evidence that sodium bicarbonate reduces the incidence of CI-AKI is encouraging but more well-designed randomized controlled trails are required to allow definitive firm conclusion to be drawn.

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

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

Changing practice to prevent contrast-induced nephropathy

Based on updated evidence, a radiology nurse systematically engaged a multidisciplinary staff in testing a protocol to prevent contrast-induced nephropathy related to computed tomography. In a quality improvement project, the protocol combined preprocedure oral hydration with postprocedure intravenous saline. This protocol safely improved kidney function, reduced postprocedure time, and decreased annual cost. By applying theory, being persistent, presenting sound evidence, and unifying the team, one concerned staff nurse profoundly affected patient care and policy in an entire medical center.

Current status of sodium bicarbonate in coronary angiography: an updated comprehensive meta-analysis and systematic review

This systematic review with meta-analysis sought to determine comparison of efficacy and safety of hydration with sodium bicarbonate versus sodium chloride on contrast induced nephropathy and clinical outcomes. We searched major electronic databases for studies in randomized controlled trials. A value of P < 0.1 for Q test or I² > 50% indicated significant heterogeneity between the studies. Literature search of all databases retrieved 650 studies. 29 studies enrolled in meta-analysis. Pooled analysis indicated about the incidence of CIN (OR of 0.718; 95% CI: 0.60 to 0.85; P = 0.000), requirement of hemodialysis (OR of 1.00; 95% CI: 0.49 to 2.01; P = 0.9), mean changes of serum creatinine (WMD of 2.321; 95% CI: 1.995 to 2.648; P = 0.000), length of hospital stays (WMD of −0.774; 95% CI: −1.65 to 0.10; P = 0.08), major adverse cardiovascular events (OR = 1.075, 95% CI: 0.59 to 1.95; P = 0.8), and mortality (OR of 0.73; 95% CI: 0.42 to 1.26; P = 0.2). Overall, hydration with sodium bicarbonate could significantly reduce CIN and the length of hospital stay compared to sodium chloride. In addition NAC added as a supplement to sodium bicarbonate could increase prophylactic effects against nephropathy.

The efficacy of sodium bicarbonate in preventing contrast-induced nephropathy in patients with pre-existing renal insufficiency: a meta-analysis

OBJECTIVE

The aim of this meta-analysis was to explore the efficacy of sodium bicarbonate in preventing contrast-induced nephropathy (CIN).

METHODS

We searched PubMed, Medline and the Cochrane Library from 1 January 2004 to 1 August 2014. The effect estimate was expressed as a pooled OR with 95% CI, using the fixed-effects or random-effects model.

RESULTS

20 randomised controlled trials (n=4280) were identified. Hydration with sodium bicarbonate was associated with a significant decrease in CIN among patients with pre-existing renal insufficiency (OR 0.67, 95% CI 0.47 to 0.96; p=0.027). However, moderate heterogeneity was noted across trials (I(2)=48%; p=0.008). Subgroup analyses indicated a better effect of sodium bicarbonate in studies using low-osmolar (OR 0.59, 95% CI 0.37 to 0.93; p=0.024) compared with iso-osmolar contrast agents (OR 0.76, 95% CI 0.43 to 1.34; p=0.351). The odds of CIN with sodium bicarbonate were lower in studies including only patients undergoing emergency (OR 0.16, 95% CI 0.05 to 0.51; p=0.002) compared with elective procedures (OR 0.76, 95% CI 0.54 to 1.06; p=0.105). Sodium bicarbonate was more beneficial in patients given a bolus injection before procedures (OR 0.15, 95% CI 0.04 to 0.54; p=0.004) compared with continuous infusion (OR 0.75, 95% CI 0.53 to 1.05; p=0.091). Sodium bicarbonate plus N-acetylcysteine (OR 0.17, 95% CI 0.04 to 0.79; p=0.024) was better than sodium bicarbonate alone (OR 0.71, 95% CI 0.48 to 1.03; p=0.071). The effect of sodium bicarbonate was considered greater in papers published before (OR 0.19, 95% CI 0.09 to 0.41; p=0.000) compared with after 2008 (OR 0.85, 95% CI 0.62 to 1.16; p=0.302). However, no significant differences were found in mortality (OR 0.69, 95% CI 0.36 to 1.32; p=0.263) or requirement for dialysis (OR 1.08, 95% CI 0.52 to 2.25; p=0.841).

CONCLUSIONS

Sodium bicarbonate is effective in preventing CIN among patients with pre-existing renal insufficiency. However, it fails to lower the risks of dialysis and mortality and therefore cannot improve the clinical prognosis of patients with CIN.

Cerebral vasospasm

Cerebral vasospasm causes delayed ischemic neurologic deficits after aneurysmal subarachnoid hemorrhage. This is a well-established clinical entity with significant associated morbidity and mortality. The underlying patholphysiology is highly complex and poorly understood. Large-vessel vasospasm, autoregulatory dysfunction, inflammation, genetic predispositions, microcirculatory failure, and spreading cortical depolarization are aspects of delayed neurologic deterioration that have been described in the literature. This article presents a perspective on cerebral vasospasm, as guided by the literature to date, specifically examining the mechanism, diagnosis, and treatment of cerebral vasospasm.

Comparison of the effects of two different formulas of fluids in craniotomy patients

Background:

Intraoperative fluid management of the patients who had undergone neurosurgery presents special challenges for the anesthesiologist. In this study, we aimed to compare the effects of two fluid combinations (half-normal + bicarbonate with saline + Ringer's lactate) on brain relaxation, and acid, base, and hemodynamic balance in patients undergoing elective craniotomy surgery.

Materials and Methods:

This randomized double-blind controlled clinical trial study was done on 50 patients, of age 20–60 years, undergoing craniotomy in Alzahra Hospital in 2012. They were divided in two groups of 25 patients each. In the control group, after the patients received hypertonic saline, normal saline serum and Ringer's lactate was administered, and in the half-normal study group, 80 ml of sodium bicarbonate for every liter of it was added. Arterial blood gas (ABG) was taken before the last suture. Brain relaxation before dura opening was registered.

Results:

There was no significant difference in heart rate changes (P = 0.054). No significant difference was observed in the mean arterial pressure between the two groups (P = 0.99). Changes in pH, HCO3, and BE were not significantly different (P = 0.99) between the two groups. Urine output in half-normal saline group was significantly higher than in normal saline group. The mean bleeding volume was higher in normal saline group, but was not significantly different (P = 0.54). The mean volume of injected blood was higher in half-normal group with a significant difference (P = 0.54). The injected blood volume mean in half-normal group was higher with no significant difference (P = 0.55). The mean of brain relaxation was not different (P = 0.5).

Conclusion:

These two fluids did not show any significant differences in the studied variables in this research.

Statins and contrast-induced acute kidney injury with coronary angiography

BACKGROUND

Contrast-induced acute kidney injury is an adverse outcome resulting from radiocontrast medium exposure during coronary angiography and percutaneous coronary intervention.

METHODS

A systematic search was conducted to retrieve studies that investigated the impact of statin exposure before coronary angiography or percutaneous coronary intervention on the development of contrast-induced acute kidney injury. The primary outcome was the development of contrast-induced acute kidney injury. We separately analyzed statin/placebo comparisons and high-/low-dose statin comparisons.

RESULTS

Fifteen randomized controlled trials met inclusion criteria: 11 studies with statin-naïve subjects, 2 studies with chronic statin users, and 2 studies with unspecified prior statin exposure. Statin exposure reduced the risk of contrast-induced acute kidney injury relative to placebo (relative risk [RR] 0.63, P = .01) with a nonsignificant reduction in the need for hemodialysis (RR 0.25, P = .08). This benefit was also observed in high-dose versus low-dose statin trials (RR 0.46, P = .004), in statin-naïve patients (RR 0.53, P <.0001), and with all studied statins. Higher statin exposure reduced contrast-induced acute kidney injury in patients with acute coronary syndromes compared with placebo or low-dose statins (RR 0.49, P <.00001), with no significant benefit among patients undergoing elective procedures (RR 0.86, P = .50). Subgroup analyses confirmed the benefit of statins in patients with diabetes, chronic kidney disease, congestive heart failure, and those receiving >140 mL of contrast dye.

CONCLUSION

Statin therapy is effective at reducing the risk of contrast-induced acute kidney injury. It should thus be considered, at least on a short-term basis, for patients at increased risk of this complication.

Do intravenous N-acetylcysteine and sodium bicarbonate prevent high osmolal contrast-induced acute kidney injury? A randomized controlled trial

BACKGROUND

N-acetylcysteine (NAC) or sodium bicarbonate (NaHCO3), singly or combined, inconsistently prevent patients exposed to radiographic contrast media from developing contrast-induced acute kidney injury (CI-AKI).

OBJECTIVE

We asked whether intravenous isotonic saline and either NaHCO3 in 5% dextrose or else a high dose of NAC in 5% dextrose prevent CI-AKI in outpatients exposed to high-osmolal iodinated contrast medium more than does saline alone.

METHODS

This completed prospective, parallel, superiority, open-label, controlled, computer-randomized, single-center, Brazilian trial (NCT01612013) hydrated 500 adult outpatients (214 at high risk of developing CI-AKI) exposed to ioxitalamate during elective coronary angiography and ventriculography. From 1 hour before through 6 hours after exposure, 126 patients (group 1) received a high dose of NAC and saline, 125 (group 2) received NaHCO3 and saline, 124 (group 3) received both treatments, and 125 (group 4) received only saline.

RESULTS

Groups were similar with respect to age, gender, weight, pre-existing renal dysfunction, hypertension, medication, and baseline serum creatinine and serum cystatin C, but diabetes mellitus was significantly less prevalent in group 1. CI-AKI incidence 72 hours after exposure to contrast medium was 51.4% (257/500), measured as serum creatinine > (baseline+0.3 mg/dL) and/or serum cystatin C > (1.1 · baseline), and 7.6% (38/500), measured as both serum creatinine and serum cystatin C > (baseline+0.3 mg/dL) or > (1.25 · baseline). CI-AKI incidence measured less sensitively was similar among groups. Measured more sensitively, incidence in group 1 was significantly (p<0.05) lower than in groups 2 and 3 but not group 4; adjustment for confounding by infused volume equalized incidence in groups 1 and 3.

CONCLUSION

We found no evidence that intravenous isotonic saline and either NaHCO3 or else a high dose of NAC prevent CI-AKI in outpatients exposed to high osmolal iodinated contrast medium more than does saline alone.

TRIAL REGISTRATION

ClinicalTrials.gov NCT01612013.

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.

Mechanisms of contrast-induced nephropathy reduction for saline (NaCl) and sodium bicarbonate (NaHCO3)

Nephropathy following contrast media (CM) exposure is reduced by administration before, during, and after the contrast procedure of either isotonic sodium chloride solution (Saline) or isotonic sodium bicarbonate solution (IsoBicarb). The reasons for this reduction are not well established for either sodium salt; probable mechanisms are discussed in this paper. For Saline, the mechanism for the decrease in CIN is likely related primarily to the increased tubular flow rates produced by volume expansion and therefore a decreased concentration of the filtered CM during transit through the kidney tubules. Furthermore, increased tubular flow rates produce a slight increase in tubular pH resulting from a fixed acid excretion in an increased tubular volume. The mechanism for the decreased CIN associated with sodium bicarbonate includes the same mechanisms listed for Saline in addition to a renal pH effect. Increased filtered bicarbonate anion raises both tubular pH and tubular bicarbonate anion levels toward blood physiologic levels, thus providing increased buffer for reactive oxygen species (ROS) formed in the tubules as a result of exposure to CM in renal tubular fluid.

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.

Higher serum chloride concentrations are associated with acute kidney injury in unselected critically ill patients

BACKGROUND

Chloride administration has been found to be harmful to the kidney in critically ill patients. However the association between plasma chloride concentration and renal function has never been investigated.

METHODS

This was a retrospective study conducted in a tertiary 24-bed intensive care unit from September 2010 to November 2012. Data on serum chloride for each patient during their ICU stay were abstracted from electronic database. Cl0 referred to the initial chloride on ICU entry, Cl(max), Cl(min) and Cl(mean) referred to the maximum, minimum and mean chloride values before the onset of AKI, respectively. AKI was defined according to the conventional AKIN criteria. Univariate and multivariable analysis were performed to examine the association of chloride and AKI development.

RESULTS

A total of 1221 patients were included into analysis during study period. Three hundred and fifty-seven patients (29.2%) developed AKI. Cl(max) was significantly higher in AKI than in non-AKI group (111.8 ± 8.1 vs 107.9 ± 5.4 mmol/l; p < 0.001); Cl0 was not significantly different between AKI and non-AKI patients; Cl(mean) was significantly higher in AKI than non-AKI (104.3 ± 5.8 vs 103.4 ± 4.5;  = 0.0047) patients. Cl(max) remained to be associated with AKI in multivariable analysis (OR: 1.10, 95% CI: 1.08-1.13).

CONCLUSION

Chloride overload as represented by Cl(mean) and Cl(max) is significantly associated with the development of AKI.

Contrast-induced nephropathy: pharmacology, pathophysiology and prevention

Modern iodinated contrast media (CM) consist of one or two tri-iodobenzene rings. They differ from each other in the composition of the side chains, creating different molecules and thus different brand substances. After intravascular administration, all CM are distributed rapidly into intravascular and extracellular fluids. They are eliminated solely by glomerular filtration. In patients with normal renal function, CMs are eliminated within 24 h. The pathophysiology of contrast-induced nephropathy (CIN) is based on three distinct but interacting mechanisms: medullary ischaemia, formation of reactive oxygen species and direct tubular cell toxicity. The contribution of each of these mechanisms to the development of CIN in the individual patient remains unclear. CIN prevention is extensively described in guidelines, such as the recently updated guideline from the Contrast Media Safety Committee (CMSC) of the European Society of Urogenital Radiology (ESUR). The recent update is briefly discussed. Furthermore, it remains unclear if volume expansion with either NaCl 0.9 % or NaHCO₃ 1.4 % is superior.

Teaching points

• After intravascular injection, CM are distributed over intravascular and extracellular fluids.

• CM are eliminated by glomerular filtration in patients with normal kidney function.

• CIN pathophysiology is based on medullary ischaemia, formation of reactive oxygen species (ROS) and tubular cell toxicity.

• It remains unclear if volume expansion with either NaCl 0.9 % or NaHCO₃1.4 % is superior.

Does bicarbonate prevent contrast-induced nephropathy in cardiovascular patients undergoing contrast imaging?

A best evidence topic in cardiovascular surgery was written according to a structured protocol. The question addressed was whether administering sodium bicarbonate (NaHCO3) prevents contrast-induced nephropathy (CIN) in cardiovascular patients undergoing contrast imaging. In total, 266 papers were found using the reported search, 16 of which represented the best evidence to answer the clinical question. The authors, journal, date and country of publication, patient group studied, study type, relevant outcomes and results of these papers are tabulated. CIN is thought to occur as a result of ischaemic or oxidative injury to the kidney. It is postulated that NaHCO3attenuates this renal damage by alkanizing renal tubular fluid thus reducing the generation of contrast-induced free radicals, which damage the kidney. Of the 16 trials, 15 recruited patients with various degrees of renal dysfunction at baseline. The benefit of using NaHCO3 was demonstrated at all stages of chronic kidney disease. Apart from four studies, 12 studies used low toxicity, low-osmolar contrast. Merten et al. published the first trial of NaHCO3 vs (saline) NaCl in preventing CIN, demonstrated a significantly lower rate in the NaHCO3 group and advocated its widespread use. Subsequent trials using the same regimen have collaborated these results. However, more recently, Gomes et al. concluded that NaHCO3 is not superior to saline-based hydration. Similarly, Brar et al. randomized 323 patients with moderate-to-severe renal insufficiency to receive either an NaHCO3 or an NaCl infusion and observed no difference in CIN rates. Two studies investigated the effects of rapid urine alkanization with bolus injections of NaHCO3 prior to contrast and found significant reductions in CIN rates compared with NaCl-treated groups. One study observed that NaCl is superior to NaHCO3, while all other studies showed a beneficial effect or no difference between NaCl- and NaHCO3-based hydration. The most recent meta-analysis by Jang et al. incorporated 3609 patients across 19 trials and concluded that NaHCO3-based hydration regimens are superior to NaCl-based ones. Based on this review, the authors recommend NaHCO3 alongside an NaCl hydration regimen. The exact regimen will depend on the context within which contrast is being administered and needs further evaluation.

Bicarbonates for the prevention of postoperative renal failure in endovascular aortic aneurysm repair: a randomized pilot trial

Purpose. Contrast-induced nephropathy (CIN) can contribute to acute kidney injury (AKI) in patients undergoing endovascular aortic aneurysm surgery. We evaluated the incidence of AKI together with the evolution of early biomarkers of renal injury in patients receiving bicarbonates or NaCl 0.9%. Methods. This study involved endovascular aortic aneurysm surgery patients. Group A (n = 17) received bicarbonates 3 mL/kg/h for 1 h before the procedure and then 1 mL/kg/h until 6 h after surgery, whereas group B (n = 17) received NaCl 0.9% using the same protocol. Biomarkers of renal injury from urine (interleukin-18 (IL-18), neutrophil gelatinase-associated lipocalin (NGAL), N-acetyl-β-D-glucosaminidase (NAG), and kidney injury molecule 1 (KIM-1)) and blood (NGAL, cystatin C) were measured at baseline and 3, 24, and 48 h postoperatively. Results. AKI occurred in 1 patient (2.9%), in the bicarbonates group. IL-18, NAG, NGAL, and KIM-1 significantly rose in both groups after the surgery. There was a greater rise in NGAL and IL-18 after 3 h in the bicarbonates versus NaCl 0.9% group: 1115% versus 240% increase (P = 0.03) and 338% increase versus 1.4% decrease (P = 0.01). Conclusions. Despite significant elevation in biomarkers of renal injury, we demonstrated a low rate of AKI following endovascular aortic surgery.

Prevention of contrast-induced AKI: a review of published trials and the design of the prevention of serious adverse events following angiography (PRESERVE) trial

Contrast-induced AKI (CI-AKI) is a common condition associated with serious, adverse outcomes. CI-AKI may be preventable because its risk factors are well characterized and the timing of renal insult is commonly known in advance. Intravenous (IV) fluids and N-acetylcysteine (NAC) are two of the most widely studied preventive measures for CI-AKI. Despite a multitude of clinical trials and meta-analyses, the most effective type of IV fluid (sodium bicarbonate versus sodium chloride) and the benefit of NAC remain unclear. Careful review of published trials of these interventions reveals design limitations that contributed to their inconclusive findings. Such design limitations include the enrollment of small numbers of patients, increasing the risk for type I and type II statistical errors; the use of surrogate primary endpoints defined by small increments in serum creatinine, which are associated with, but not necessarily causally related to serious, adverse, patient-centered outcomes; and the inclusion of low-risk patients with intact baseline kidney function, yielding low event rates and reduced generalizability to a higher-risk population. The Prevention of Serious Adverse Events following Angiography (PRESERVE) trial is a randomized, double-blind, multicenter trial that will enroll 8680 high-risk patients undergoing coronary or noncoronary angiography to compare the effectiveness of IV isotonic sodium bicarbonate versus IV isotonic sodium chloride and oral NAC versus oral placebo for the prevention of serious, adverse outcomes associated with CI-AKI. This article discusses key methodological issues of past trials investigating IV fluids and NAC and how they informed the design of the PRESERVE trial.

Contrast-induced acute kidney injury following PCI

BACKGROUND

Coronary revascularization using percutaneous coronary intervention (PCI) is one of the major treatments for patients with stable coronary artery disease, with approximately 1.5 million patients undergoing PCI in the United States and Europe every year. An important neglected complication of PCI is contrast-induced acute kidney injury (CI-AKI).

DESIGN

In this article, we review the definition, pathogenesis and management of CI-AKI and highlight potential therapeutic options for preventing CI-AKI in post-PCI patients.

RESULTS

CI-AKI is an important but underdiagnosed complication of PCI that is associated with increased in-hospital morbidity and mortality. Patients with pre-existing renal impairment and diabetes are particularly susceptible to this complication post-PCI. Optimization of the patients' circulating volume remains the mainstay for preventing CI-AKI, although the best strategy for achieving this is still controversial.

CONCLUSION

Following PCI, CI-AKI is an overlooked complication which is associated with significant morbidity and mortality. In this article, we review the pathophysiology of CI-AKI in patients undergoing PCI and discuss the potential therapeutic options for preventing it.

Extended Stability of Sodium Bicarbonate Infusions Prepared in Polyolefin Bags

Purpose

To investigate the stability of 0.1 mEq/mL and 0.15 mEq/mL strengths of extemporaneously compounded sodium bicarbonate preparations.

Methods

Sterile preparations of sodium bicarbonate of 2 strengths (0.1 mEq/mL and 0.15 mEq/mL) were compounded in accordance with USP <797> standards. To carry out the stability testing, these products were stored under 3 temperature conditions: −20°C, 2°C-8°C, and 23°C-25°C. Under the stability studies, pH, particulate matter, and the active content were monitored for 30 days.

Results

Sodium bicarbonate infusions are stable for 21 days when stored at −20°C or 2°C −8°C and are stable for 7 days when stored at room temperature (23°C-25°C). These data demonstrate that sodium bicarbonate infusions have extended physical and chemical stability after preparation.

Conclusions

The stability analysis results show that the observed shelf life was far better than the recommended expiration dates. This will allow the hospitals to give longer dating to sodium bicarbonate preparations, provided they are prepared in a sterile environment and are in compliance with USP <797> guidelines.

Preventing radiocontrast-induced nephropathy in chronic kidney disease patients undergoing coronary angiography

Radiocontrast-induced nephropathy (RCIN) is an acute and severe complication after coronary angiography, particularly for patients with pre-existing chronic kidney disease (CKD). It has been associated with both short- and long-term adverse outcomes, including the need for renal replacement therapy, increased length of hospital stay, major cardiac adverse events, and mortality. RCIN is generally defined as an increase in serum creatinine concentration of 0.5 mg/dL or 25% above baseline within 48 h after contrast administration. There is no effective therapy once injury has occurred, therefore, prevention is the cornerstone for all patients at risk for acute kidney injury (AKI). There is a small but growing body of evidence that prevention of AKI is associated with a reduction in later adverse outcomes. The optimal strategy for preventing RCIN has not yet been established. This review discusses the principal risk factors for RCIN, evaluates and summarizes the evidence for RCIN prophylaxis, and proposes recommendations for preventing RCIN in CKD patients undergoing coronary angiography.

Contrast-induced nephropathy--a review of current literature and guidelines

The use of iodine-based contrast agents always entails the risk of contrast-induced nephropathy (CIN). The recently observed dramatic increase in the number of examinations and therapeutic procedures using iodine-based contrast media led us to conduct a thorough analysis of the growing number of scientific reports and collective works devoted to contrast-induced nephropathy, based on current definitions, epidemiology, pathophysiology, risk factors, successful prophylaxis and guidelines of the European Society of Urogenital Radiology (ESUR).

Radiological contrast agents are the third most common cause of nephropathy among in-patients, accounting for 11–12% of cases. CIN is connected with some clinically significant consequences, including increased morbidity, prolonged hospitalisation, increased risk of complications, potential need for dialysis and increased mortality rate. A significant increase in the number of examinations applying iodine-based contrast media in the course of inpatient procedures requires close cooperation of the clinician and radiologist, supported by knowledge of all CIN issues. In order to protect patients from contrast-induced nephropathy, it is necessary to monitor their renal function, indentify patients with risk factors, refer patients for examinations in a responsible manner, and undertake successful preventive measures.

Contrast-induced acute kidney injury: short- and long-term implications

The intravascular administration of iodine-based contrast media remains a common cause of acute kidney injury and a leading cause of iatrogenic renal disease. Past research has elucidated the principal risk factors for contrast-induced acute kidney injury (CIAKI) and helped to establish the efficacy of various interventions for the prevention of this condition. The importance of preventing CIAKI has been underscored by a growing number of studies showing strong associations of CIAKI with serious adverse short- and long-term outcomes. However, it remains unclear whether these associations are causal. This is important because considerable health care resources are used to prevent CIAKI. If CIAKI is a marker, but not a mediator, of serious adverse downstream outcomes, more judicious and selective use of preventive care may be appropriate. Moreover, with an increasing number of studies reporting the underuse of coronary angiography in patients with acute coronary syndrome and underlying chronic kidney disease, presumably in part because of a fear of CIAKI, a clear understanding of whether this condition directly results in adverse downstream outcomes is essential. Careful inspection of past studies that investigated the association of CIAKI with adverse short- and long-term events sheds light on their strengths and weaknesses and provides insight into how future research may be better able to characterize the short- and long-term implications of this iatrogenic condition.