Intravenous N-acetylcysteine for prevention of contrast-induced nephropathy: a meta-analysis of randomized, controlled trials

Navigating nephrotoxic waters: A comprehensive overview of contrast-induced acute kidney injury prevention

Contrast-induced acute kidney injury (CI-AKI) is the third leading cause of acute kidney injury deriving from the intravascular administration of contrast media in diagnostic and therapeutic procedures and leading to longer in-hospital stay and increased short and long-term mortality. Its pathophysiology, although not well-established, revolves around medullary hypoxia paired with the direct toxicity of the substance to the kidney. Critically ill patients, as well as those with pre-existing renal disease and cardiovascular comorbidities, are more susceptible to CI-AKI. Despite the continuous research in the field of CI-AKI prevention, clinical practice is based mostly on periprocedural hydration. In this review, all the investigated methods of prevention are presented, with an emphasis on the latest evidence regarding the potential of RenalGuard and contrast removal systems for CI-AKI prevention in high-risk individuals.

Endogenous and Exogenous Antioxidants as Agents Preventing the Negative Effects of Contrast Media (Contrast-Induced Nephropathy)

The use of conventional contrast media for diagnostic purposes (in particular, Gd-containing and iodinated agents) causes a large number of complications, the most common of which is contrast-induced nephropathy. It has been shown that after exposure to contrast agents, oxidative stress often occurs in patients, especially in people suffering from various diseases. Antioxidants in the human body can diminish the pathological consequences of the use of contrast media by suppressing oxidative stress. This review considers the research studies on the role of antioxidants in preventing the negative consequences of the use of contrast agents in diagnostics (mainly contrast-induced nephropathy) and the clinical trials of different antioxidant drugs against contrast-induced nephropathy. Composite antioxidant/contrast systems as theranostic agents are also considered.

The Combined Treatment of Glutathione Sodium Salt and Ascorbic Acid for Preventing Contrast-Associated Acute Kidney Injury in ST-Elevation Myocardial Infarction Patients Undergoing Primary PCI: A Hypothesis to Be Validated

The occurrence of Contrast-Associated Acute Kidney Injury (CA-AKI) in patients with ST-Elevation Myocardial Infarction (STEMI) has a negative impact on the length of hospital stay and mortality. Reactive Oxygen Species (ROS) release, along with vasoconstriction and hypoperfusion, play a key role in its development. To date, there is still no validated prophylactic therapy for this disease. The use of antioxidants, based on experimental and clinical studies, looks promising. Taking into consideration previous literature, we speculate that an early, combined and prolonged intravenous administration of both Glutathione (GSH) and ascorbic acid in STEMI patients undergoing primary Percutaneous Coronary Intervention (pPCI) may be of value in counteracting the occurrence of CA-AKI. We aimed at evaluating this hypothesis by applying a multicenter research protocol, using a double-blind randomized, placebo-controlled trial design. The primary endpoint will be to test the efficacy of this combined antioxidant therapy in reducing the occurrence of renal damage, in patients with acute myocardial infarction treated with pPCI. Furthermore, we will investigate the effect of the study compounds on changes in oxidative stress markers and platelet activation levels through bio-humoral analyses.

Pharmacological agents for the prevention of colistin-induced nephrotoxicity

Background

Colistin is a polymyxin antibiotic which has been used for treatment of Gram-negative infections, but it was withdrawn due to its nephrotoxicity. However, colistin has gained its popularity in recent years due to the reemergence of multidrug resistant Gram-negative infections and drug-induced toxicity is considered as the main obstacle for using this valuable antibiotic.

Results

In total, 30 articles, including 29 animal studies and one clinical trial were included in this study. These compounds, including aged black garlic extract, albumin fragments, alpha lipoic acid, astaxanthin, baicalein, chrysin, cilastatin, colchicine, curcumin, cytochrome c, dexmedetomidine, gelofusine, grape seed proanthocyanidin extract, hesperidin, luteolin, lycopene, melatonin, methionine, N-acetylcysteine, silymarin, taurine, vitamin C, and vitamin E exhibited beneficial effects in most of the published works.

Conclusions

In this review, the authors have attempted to review the available literature on the use of several compounds for prevention or attenuation of colistin-induced nephrotoxicity. Most of the studied compounds were potent antioxidants, and it seems that using antioxidants concomitantly can have a protective effect during the colistin exposure.

Contrast-Associated Acute Kidney Injury

Contrast-associated acute kidney injury (CA-AKI) is an impairment of renal function, which occurs within days of intravascular administration of iodinated contrast media. Taking into account that minimally invasive cardiac interventions are becoming increasingly popular, compared to traditional surgery, given their impact on prognosis and costs, CA-AKI remains a subject of increasing interest for patients and physicians. This review summarizes the epidemiology and risk stratification, diagnostic criteria, pathophysiology and clinical implications of CA-AKI, providing evidence for the most studied preventive strategies.

Contrast associated nephropathy after intravenous administration: what is the magnitude of the problem?

Intravenous contrast media (CM) is often used in clinical practice to enhance CT scan imaging. For many years, contrast-induced nephropathy (CIN) was thought to be a common occurrence and to result in dire consequences. When treating patients with abnormal renal function, it is not unusual that clinicians postpone, cancel, or replace contrast-enhanced imaging with other, perhaps less informative tests. New studies however have challenged this paradigm and the true risk attributable to intravenous CM for the occurrence of CIN has become debatable. In this article, we review the latest relevant medical literature and aim to provide an evidence-based answer to questions surrounding the risk, outcomes, and potential mitigation strategies of CIN after intravenous CM administration.

Renoprotective effect of N-acetylcysteine depends upon the severity of the ischemia reperfusion injury

Acute kidney injury (AKI) is a common complication in seriously ill patients, while renal ischemia-reperfusion (I/R) injury is the most frequent event in this oxidative renal injury. N-acetylcysteine (NAC) is a small molecule containing a thiol group that has antioxidant properties, promoting detoxification and acting directly as a free radical scavenger. In this study, the protective effect of NAC was investigated in short-term (30 min) and long-term (45 min) ischemic AKI. This was achieved via clamping of the renal artery for 30 or 45 min in Wistar rats to induce I/R injury. AKI worsened with a longer period of ischemia (45 compared to 30 min) due to probable irreversible damage. Preconditioning with NAC in short-term ischemia improved renal blood flow and increased creatinine clearance by reducing oxidative metabolites and increasing antioxidant capacity. Otherwise, NAC did not change these parameters in the long-term ischemia. Therefore, this study demonstrated that the period of ischemia determines the severity of the AKI, and NAC presented antioxidant effects in short-term ischemia but not in long-term ischemia, confirming that there is a possible therapeutic window for its renoprotective effect.

Protective action of N-acetyl-L-cysteine associated with a polyvalent antivenom on the envenomation induced by Lachesis muta muta (South American bushmaster) in rats

In this study, we examined the potential use of N-acetyl-L-cysteine (NAC) in association with a polyvalent antivenom and as stand-alone therapy to reduce the acute local and systemic effects induced by Lachesis muta muta venom in rats. Male Wistar rats (300-350 g) were exposed to L. m. muta venom (1.5 mg/kg - i.m.) and subsequently treated with anti-Bothrops/Lachesis serum (antivenom:venom ratio 1:3 'v/w' - i.p.) and NAC (150 mg/kg - i.p.) separately or in association; the animals were monitored for 120 min to assess changes in temperature, locomotor activity, local oedema formation and the prevalence of haemorrhaging. After this time, animals were anesthetized in order to collect blood samples through intracardiac puncture and then euthanized for collecting tissue samples; the hematological-biochemical and histopathological analyses were performed through conventional methods. L. m. muta venom produced pronounced local oedema, subcutaneous haemorrhage and myonecrosis, with both antivenom and NAC successfully reducing the extent of the myonecrotic lesion when individually administered; their association also prevented the occurrence of subcutaneous haemorrhage. Venom-induced creatine kinase (CK) release was significantly prevented by NAC alone or in combination with antivenom; NAC alone failed to reduce the release of hepatotoxic (alanine aminotransferase) and nephrotoxic (creatinine) serum biomarkers induced by L. m. muta venom. Venom induced significant increase of leucocytes which was also associated with an increase of neutrophils, eosinophils and monocytes; antivenom and NAC partially reduced these alterations, with NAC alone significantly preventing the increase of eosinophils whereas neither NAC or antivenom prevented the increase in monocytes. Venom did not induce changes in the erythrogram parameters. In the absence of a suitable antivenom, NAC has the potential to reduce a number of local and systemic effects caused by L. m. muta venom.

Clinical Remission Using Personalized Low-Dose Intravenous Infusions of N-acetylcysteine with Minimal Toxicities for Interstitial Cystitis/Bladder Pain Syndrome

Interstitial Cystitis or Bladder Pain Syndrome (IC/BPS) is a heterogeneous condition characterized by elevated levels of inflammatory cytokines, IL-1β, IL-6, IL-8, IL-10, TNF-α, and is associated with debilitating symptoms of pelvic pain and frequent urination. A standard of care for IC/BPS has not been established, and most patients must undergo a series of different treatment options, with potential for severe adverse events. Here, we report a patient with a 26-year history of IC/BPS following treatment with multiple therapies, including low doses of etodolac, amitriptyline and gabapentin, which she was unable to tolerate because of adverse effects, including headaches, blurred vision and cognitive impairment. The patient achieved a complete clinical remission with minimal adverse events after 16 cycles of N-acetylcysteine (NAC) intravenous (IV) infusions over a period of 5 months, and pro-inflammatory cytokine levels were reduced when compared to measurements taken at presentation. Personalized low dose NAC IV infusion therapy represents an effective, safe, anti-inflammatory therapy administered in the outpatient setting for IC/BPS, and warrants further investigation.

Comparison of Oral and Intravenous N-acetyl Cysteine in Preventing Contrast Nephropathy

Introduction

Despite high rates of morbidity and mortality in patients with contrast-induced nephropathy (CIN), there is no consensus regarding prevention of this well-known complication of contrast media use. One agent that has been widely used in this regard is N-acetyl cysteine (NAC). Nevertheless, its efficacy is still controversial. The aim of this study was to assess the efficacy of NAC, both in the oral and intravenous forms, for the prevention of CIN.

Methods

This study is a double-blind randomized placebo controlled clinical trial. We randomized 434 adult patients with chronic kidney disease (constant serum creatinine ≥1.5 mg/dL) who were candidates for coronary angiography/plasty. The patients were categorized into three groups. One group received 1,200 mg NAC intravenously half an hour before the procedure and oral placebo starting 3 days before angiography. The second group received oral NAC 600 mg twice daily for 3 days, starting the day before the intervention and intravenous placebo half an hour before intervention. The third group received both oral and intravenous placebo. CIN was defined as a 25% relative increase in serum creatinine from baseline value, 48 h after use of contrast medium.

Results

Of the 434 patients, 149 received intravenous NAC, 145 received oral NAC, and the remaining 140 received placebo. The incidence of CIN in the three groups was 6.1%, 7.6%, and 10.8%, respectively (p = 0.34).

Conclusion

In patients with chronic kidney disease, neither intravenous nor oral NAC is superior to placebo for preventing CIN.

Latest Clinical Evidence About Effect of Acetylcysteine on Preventing Contrast-Induced Nephropathy in Patients Undergoing Angiography: A Meta-Analysis

Contrast-induced nephropathy (CIN) is a serious complication of angiographic procedures. It is the third most common cause of hospital acquired acute renal injury. As there are currently no approved therapies for CIN, prevention could be the best strategy to address this issue. Acetylcysteine may indirectly play an antioxidant role by inducing the synthesis of glutathione. Acetylcysteine can also reduce renal vasoconstriction induced by contrast medium stimulation by stabilizing nitric oxide and acting directly or indirectly on renal cortex and medulla microcirculation. To evaluate the effect of acetylcysteine on the prevention of CIN in patients after angiography, we systematically searched and analyzed the clinical data of patients including the incidence of CIN and change in serum creatinine (SCr) at 48 hours after angiography from selected articles. The result showed that acetylcysteine significantly reduces the incidence of CIN (risk ratios: 0.78, 95% CI: 0.68-0.90, I ² = 37.3%) and the level of SCr (standardized mean difference: -0.53, 95% CI: -0.93 to -0.12, I ² = 91.5%) after angiography compared with the control group. Overall, the use of acetylcysteine in patients after angiography was associated with a significant reduction of CIN and the level of SCr.

DDAH-2 alleviates contrast medium iopromide-induced acute kidney injury through nitric oxide synthase

BACKGROUND

Contrast medium-induced acute kidney injury (CI-AKI) is one of the most common causes of hospital-acquired acute renal failure. However, the pathogenesis of CI-AKI remains unclear. Asymmetric dimethylarginine (ADMA) is an endogenous nitric oxide synthase (NOS) inhibitor that is largely metabolised by dimethylarginine dimethylaminohydroxylase (DDAH) in humans. Two isoforms of DDAH exist, namely, DDAH-1 and DDAH-2. In the present study, we examined whether the DDAH-2/ADMA/NOS pathway is involved in the pathogenesis of CI-AKI.

METHODS AND RESULTS

Exposure to the contrast medium iopromide led to increase in creatinine and blood urea nitrogen (BUN) levels, accumulation of ADMA, increase in reactive oxygen species (ROS) generation, and an inflammatory response in mice kidney tissue. The injection of adenovirus-harbouring DDAH-2 lowered renal ADMA levels and had a reno-protective effect against contrast-medium injury by decreasing cell apoptosis, ROS, and fibrosis. By contrast, contrast medium-induced renal injury was exacerbated in heterozygous DDAH-2 knockout mice. In the in vitro study, overexpression of DDAH-2 increased the levels of nitrite and intracellular cGMP, while the DDAH-2 knockdown induced the opposite effect. These findings were also observed in the in vivo sample.

CONCLUSIONS

Our findings provide the first evidence that the DDAH-2/ADMA/NOS pathway is involved in the pathogenesis of CI-AKI and that the protective effect of DDAH-2 probably arises from the modulation of NOS activity, oxidative stress, and the inflammatory process.

Coronary CT Angiography Using Low Iodine Delivery Rate and Tube Voltage Determined by Body Mass Index: Superiority in Clinical Practice

To explore the feasibility and superiority of iodine delivery rate (IDR) and tube voltage determined by patients' body mass index (BMI) in coronary CT angiography (CCTA), a total of 1567 patients undertaking CCTA during Feb. and Dec. 2016 were enrolled and divided into two groups. In the control group, the IDR and tube voltage were fixed, while in the experimental group, the IDR and tube voltage were determined by patients' BMI. The volume of iodinated contrast media (ICM), extravasation rate, extravasation volume, extravasation recovery interval, incidence rate of adverse reactions, effective dose (ED) and image quality of the two groups were compared. The experiments demonstrated that the ICM volume, extravasation rate, extravasation volume, extravasation recovery interval, incidence of adverse reactions and ED were lower or shorter in the experimental group than in the control group, and the differences were statistically significant (all P<0.05). However, there were no significant differences in the mean CT value, image noise, signal to noise ratio and contrast to noise ratio between the two groups (all P<0.05), which were consistent with the diagnosticians' subjective evaluation outcomes. Our findings suggested that in CCTA, it is feasible to determine the IDR and tube voltage based on patients' BMI; low tube voltage and IDR are superior to the fixed tube voltage and IDR and are worthy of clinical promotion.

Analysis of the risk factors for contrast-induced nephropathy in over-aged patients receiving coronary intervention

Contrast-induced nephropathy has been the common cause of hospital-acquired acute kidney injury in the elderly patients. This study aimed to analyze the risk factors for contrast-induced nephropathy in over-aged patients undergoing coronary angiography or percutaneous coronary intervention. A total of 470 over-aged patients (≥80 years old) were judged as the contrast-induced nephropathy group ( n = 46) and non-contrast-induced nephropathy group ( n = 424) according to the postoperative 48-h serum creatinine levels. The patients' clinical information such as hypertension grade, number and degree of coronary artery stenosis, and death rate was compared. The risk factors for contrast-induced nephropathy were also analyzed. The hypertension grade in the contrast-induced nephropathy group was significantly higher than that in the non-contrast-induced nephropathy group ( P = 0.004). The degree of coronary artery stenosis was significantly more in the contrast-induced nephropathy group compared with the non-contrast-induced nephropathy group ( P = 0.003). The death rate of the contrast-induced nephropathy group (15.8%) was significantly higher than that of the non-contrast-induced nephropathy group (0.6%; P = 0.000). The percentage of patients with abnormal urine microalbumin was significantly bigger in the contrast-induced nephropathy group (62.5%) when comparing to the non-contrast-induced nephropathy group (23.6%; P = 0.00). Besides, there was also significant difference in the emergency/selective operation between the contrast-induced nephropathy group and non-contrast-induced nephropathy group ( P = 0.001). Further, hypertension grade ( P = 0.019), emergency/selective operation ( P = 0.025), degree of coronary artery stenosis ( P = 0.038), eGFR ( P = 0.034), and urine microalbumin ( P = 0.005) were the risk factors for contrast-induced nephropathy. Hypertension grade, emergency/selective operation, degree of coronary artery stenosis, eGFR, and urine microalbumin were the risk factors for contrast-induced nephropathy in over-aged patients receiving coronary angiography and percutaneous coronary intervention, providing guidance for the clinical prevention of contrast-induced nephropathy. Impact statement In this work, we evaluated the risk factors for contrast-induced nephropathy (CIN) in over-aged patients receiving coronary angiography (CAG) and percutaneous coronary intervention (PCI). We found that hypertension grade, emergency/selective operation, degree of coronary artery stenosis, eGFR, and urine microalbumin were the risk factors for CIN in over-aged patients receiving CAG and PCI. This study provides guidance for the clinical prevention of CIN in over-aged patients undergoing coronary intervention, highlighting that a perioperative comprehensive management strategy is needed to improve the prognosis.

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

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.

Predictive factors for contrast-induced acute kidney injury in high-risk patients given N-acetylcysteine prophylaxis

BACKGROUND

Contrast-induced acute kidney injury (CI-AKI) is rec.ognized as a common complication of radiographic contrast-enhanced procedures. N-acetylcysteine (NAC) is commonly prescribed, but CI-AKI can still develop despite NAC administration as prophylaxis.

OBJECTIVE

Identify the predictive factors for development of CI-AKI in patients prescribed NAC.

DESIGN

Prospective, cross-sectional.

SETTING

A tertiary hospital in Malaysia.

PATIENTS AND METHODS

All adult patients who were prescribed NAC for prevention of CI-AKI were identified through an NAC drug us.age monitoring card maintained by the inpatient pharmacy. The study was conducted from March to July 2017.

MAIN OUTCOME MEASURES

Statistically significant predictive fac.tors for development of CI-AKI despite NAC administration.

SAMPLE SIZE

152 RESULTS: The most commonly recognized risk factors for CI-AKI present in the study population were renal impairment (n=131, 86.2%), anemia (n=107, 70.4%), and diabetes mellitus (n=90, 59.2%). Hydration therapy was initiated in 128 patients (84.2%) prior to the contrast-enhanced procedure. Sixty-one (40.1%) were treated with nephrotoxic medications concomitantly with NAC. Fifteen (9.9%) patients developed AKI. Hypotension (OR: 6.02; 95% CI 1.25-28.97) and use of high contrast volume (OR: 6.56; 95% CI: 1.41-30.64) significantly increased the odds for AKI. Prior hydration therapy (OR: 0.13; 95% CI 0.03-0.59) showed protective effects.

CONCLUSION

The risk predictors identified for CI-AKI were hypotension, high contrast volume and prior hydration therapy.

LIMITATION

May not have identified other confounding factors for development of CI-AKI.

CONFLICT OF INTEREST

None.

Intravenous N-acetylcysteine for the PRevention Of Contrast-induced nephropathy - a prospective, single-center, randomized, placebo-controlled trial. The INPROC trial

INTRODUCTION

Contrast-induced nephropathy (CIN) is a common clinical problem that is growing in importance as an increasing number of tests and procedures which utilize contrast media (CM) are performed.

AIM

To evaluate the efficacy of intravenous N-acetylcysteine (NAC) for prevention of CIN after diagnostic and/or interventional procedures requiring CM administration.

MATERIAL AND METHODS

In a prospective, single-center, randomized, placebo-controlled trial the preventive effects of N-acetylcysteine were evaluated in 222 patients undergoing elective angiography and/or angioplasty. Patients were randomly assigned to receive either NAC or placebo. All patients received intravenous hydration with normal saline before and after catheterization. Serum creatinine (SCr) and estimated glomerular filtration rate were assessed at baseline, at 48-72 h and 10-15 days after CM administration. Contrast-induced nephropathy was defined as an increase in SCr of at least 44 µmol/l (0.5 mg/dl) or an increase of ≥ 25% of the baseline value 48-72 h after CM administration.

RESULTS

Contrast-induced nephropathy occurred in 30 of 222 patients (13.5%): 9 of 108 patients in NAC (8.3%) and 21 of 114 patients in the control group (18.4%; p = 0.0281). The multivariate Cox analysis revealed that elevated SCr at 10-15 days (HR = 2.69; p = 0.018) and baseline SCr level (HR = 1.009; p = 0.015) were independent prognostic variables for adverse events during follow-up.

CONCLUSIONS

Our findings suggest that intravenous NAC along with intravenous hydration may help prevent declining renal function after CM exposure. Elevated SCr level 10-15 days after CM administration was associated with increased risk of adverse events in long-term observation, while elevated SCr within 72 h was not. Measuring SCr at least 10 days after exposure to CM may provide a better outcome measure.

Drug-Induced Kidney Injury in the Elderly

The incidence of acute kidney injury in the elderly has grown over the past decade. One of the primary drivers is drug-induced nephrotoxicity, which is the result of a combination of the unique susceptibilities to kidney injury and the increased use of medications in the elderly population. Specific drug classes are associated with increased rates of kidney injury including agents that block the renin angiotensin system, antimicrobials, and chemotherapeutic agents. Mechanistically, injury may be due to hemodynamic effects, tubular or glomerular toxicity, and interstitial nephritis. Early recognition of nephrotoxicity is critical, as are preventative steps when applicable. Unfortunately, treatment for established drug-induced kidney injury is limited and supportive care is required. Limiting exposure to nephrotoxic drugs is critical in decreasing the incidence of acute kidney injury in the elderly patient.

Contrast-Induced Nephropathy in STEMI Patients With and Without Chronic Kidney Disease

INTRODUCTION

Contrast-induced nephropathy (CIN) following percutaneous coronary intervention (PCI) is associated with adverse outcomes; however, there are scarce data comparing clinical outcomes of post-PCI CIN in ST elevation myocardial infarction (STEMI) patients with and without chronic kidney disease (CKD). We sought to assess the incidence, clinical predictors, and short-term and long-term clinical outcomes of post-PCI CIN in STEMI patients with and without CKD.

METHODS

We performed a retrospective observational cohort study involving 554 patients who underwent PCI for STEMI from February 2010 to November 2013. CKD was defined as estimated glomerular filtration rate ≤60 mL/min and CIN as creatinine increase by ≥25% or ≥0.5 mg/dL from baseline within 72 hours after catheterization contrast exposure.

RESULTS

In the entire population, CIN developed in 89 (16%) patients. The incidence of CIN was 19.7% (27/137) in CKD patients and 11.1% (62/417) in non-CKD patients, P < 0.05. Univariate analysis predictors of CIN were older age (65 vs. 60 years), diabetes (35% vs. 21%), peripheral artery disease (11% vs. 5%), cardiogenic shock (24% vs. 13%), hemodynamic support placement (34% vs. 14%), and Mehran score (9.4 ± 7 vs. 5.4 ± 5.2) with all P < 0.05. The predictors of CIN were the same across the CKD and non-CKD cohort with the exception of diabetes. In multivariate analysis, the strongest predictor of CIN in CKD patients was diabetes (odds ratio, 5.8; CI, 1.8-18.6); however, diabetes was not a predictor in the non-CKD population. In the non-CKD population, each single unit increase in the Mehran score was associated with a 1.1 times greater likelihood of CIN (odds ratio, 1.1; CI, 1.01-1.2). Patients with CIN had higher rates of inpatient mortality (14.6% vs. 2.8%), longer length of hospitalization (8 ± 11 vs. 3.4 ± 4.4 days), need for inpatient dialysis (11.2% vs. 0%), higher 30-day mortality (14.6% vs. 3.0%), and higher incidence of long-term serum creatinine >0.5 mg/dL from baseline (16.9% vs. 2.4%) with all P < 0.05.

CONCLUSIONS

Overall, we found that CKD patients undergoing PCI for STEMI have a higher incidence of CIN than non-CKD patients. CIN confers worse short-term and long-term outcomes irrespective of baseline renal function.

Oral N-acetylcysteine for prophylaxis of contrast-induced nephropathy in patients following coronary angioplasty: A meta-analysis

It is acknowledged that contrast-induced nephropathy (CIN) is a common cause of acute renal insufficiency after cardiac catheterization and affects mortality and morbidity. To date, it is unknown whether oral N-acetylcysteine (NAC) is able to prevent contrast-induced nephropathy (CIN) in patients undergoing coronary angioplasty. A meta-analysis of randomized controlled trials was performed to assess the effects of NAC in the prevention of CIN in patients following coronary angioplasty. A total of 19 studies published prior to January 2015 that investigated the efficacy of oral NAC for the prevention of CIN were collected from Medline, Cochrane and Embase databases and conference proceedings from cardiology and nephrology meetings. The primary point of investigation was CIN, and the secondary points were renal failure requiring dialysis, mortality and length of hospitalization. The meta-analysis was performed using fixed- or random-effect models according to heterogeneity. Up to January 2015, 19 randomized placebo-controlled clinical trials met the inclusion criteria for the meta-analysis, including 4,514 patients. The pooled data showed that oral NAC did not reduce the CIN incidence [relative risk 0.84, 95% confidence interval (CI) 0.65-1.10; P=0.20], without heterogeneity among trials (I2=29%). Thus, the present meta-analysis suggests that oral NAC therapy is not effective as an alternative treatment to prevent CIN in patients following angioplasty. Further high quality randomized clinical controlled trials are required to confirm the usage and availability of this treatment.

Prevention of acute kidney injury and protection of renal function in the intensive care unit: update 2017 : Expert opinion of the Working Group on Prevention, AKI section, European Society of Intensive Care Medicine

BACKGROUND

Acute kidney injury (AKI) in the intensive care unit is associated with significant mortality and morbidity.

OBJECTIVES

To determine and update previous recommendations for the prevention of AKI, specifically the role of fluids, diuretics, inotropes, vasopressors/vasodilators, hormonal and nutritional interventions, sedatives, statins, remote ischaemic preconditioning and care bundles.

METHOD

A systematic search of the literature was performed for studies published between 1966 and March 2017 using these potential protective strategies in adult patients at risk of AKI. The following clinical conditions were considered: major surgery, critical illness, sepsis, shock, exposure to potentially nephrotoxic drugs and radiocontrast. Clinical endpoints included incidence or grade of AKI, the need for renal replacement therapy and mortality. Studies were graded according to the international GRADE system.

RESULTS

We formulated 12 recommendations, 13 suggestions and seven best practice statements. The few strong recommendations with high-level evidence are mostly against the intervention in question (starches, low-dose dopamine, statins in cardiac surgery). Strong recommendations with lower-level evidence include controlled fluid resuscitation with crystalloids, avoiding fluid overload, titration of norepinephrine to a target MAP of 65-70 mmHg (unless chronic hypertension) and not using diuretics or levosimendan for kidney protection solely.

CONCLUSION

The results of recent randomised controlled trials have allowed the formulation of new recommendations and/or increase the strength of previous recommendations. On the other hand, in many domains the available evidence remains insufficient, resulting from the limited quality of the clinical trials and the poor reporting of kidney outcomes.

Acute kidney injury in the perioperative period and in intensive care units (excluding renal replacement therapies)

Acute kidney injury (AKI) is a syndrome that has progressed a great deal over the last 20 years. The decrease in urine output and the increase in classical renal biomarkers, such as blood urea nitrogen and serum creatinine, have largely been used as surrogate markers for decreased glomerular filtration rate (GFR), which defines AKI. However, using such markers of GFR as criteria for diagnosing AKI has several limits including the difficult diagnosis of non-organic AKI, also called "functional renal insufficiency" or "pre-renal insufficiency". This situation is characterized by an oliguria and an increase in creatininemia as a consequence of a reduction in renal blood flow related to systemic haemodynamic abnormalities. In this situation, "renal insufficiency" seems rather inappropriate as kidney function is not impaired. On the contrary, the kidney delivers an appropriate response aiming to recover optimal systemic physiological haemodynamic conditions. Considering the kidney as insufficient is erroneous because this suggests that it does not work correctly, whereas the opposite is occurring, because the kidney is healthy even in a threatening situation. With current definitions of AKI, normalization of volaemia is needed before defining AKI in order to avoid this pitfall.

Effectiveness of N-Acetylcysteine for the Prevention of Contrast-Induced Nephropathy: A Systematic Review and Meta-Analysis of Randomized Controlled Trials

Background

Conflicting results have been obtained in trials that have evaluated the prophylactic efficacy of N‐acetylcysteine (NAC) pretreatment in the prevention of contrast‐induced nephropathy (CIN). In this meta‐analysis of randomized controlled trials, we aimed to assess the effectiveness of NAC treatment for the prevention of CIN.

Methods and Results

PubMed, EMBASE, and the Cochrane Library were electronically searched from inception to January 2016 for all relevant studies. The weighted relative risk (RR) and corresponding 95% CI for incident CIN were estimated using random effects models. Standard methods for assessing statistical heterogeneity and publication bias were used. The study included 11 480 participants and 1653 cases of CIN. The incidence of CIN was 12.8% in the NAC group versus 16.0% in the control group (RR: 0.76, 95% CI: 0.66–0.88, P=0.0002). In the patients undergoing coronary angiography, the incidence of CIN in the NAC group versus the control group was 13.7% versus 17.2% (RR: 0.74, 95% CI: 0.63–0.87, P=0.0002); in those undergoing peripheral angiography, the incidence was 6.4% versus 5.8% (RR: 1.00, 95% CI: 0.42–2.40, P=1.00); in those undergoing computed tomography, the incidence was 7.7% versus 14.8% (RR: 0.51, 95% CI: 0.29–0.89, P=0.02).

Conclusions

Our meta‐analysis showed an inverse and significant association between NAC supplementation and risk of CIN in patients undergoing coronary angiography and computed tomography, while a protective role for NAC in patients undergoing peripheral angiography was not obvious.

Effect of statins in preventing contrast-induced nephropathy: an updated meta-analysis

OBJECTIVE

The effect of statins in preventing contrast-induced nephropathy (CIN) has been reported, with conflicting results. The aim of this study was to carry out an updated meta-analysis to determine whether pretreatment with statins can reduce the risk of CIN and adverse clinical events.

MATERIALS AND METHODS

Systematic database searches of MEDLINE (1950 to December 2013), EMBASE (1966 to December 2013), and the Cochrane Central Register of Controlled Trials (Issue 12, December 2013) were performed. All randomized controlled trials assessing the efficacy of statins on CIN were included.

RESULTS

Seventeen studies with 6323 patients were included. Pretreatment with statins before angiography significantly reduced the risk of CIN [relative risk 0.50; 95% confidence interval (CI) 0.35-0.71; P<0.001] and was associated with significantly lower postprocedural serum creatinine levels (weighted mean difference -0.05 mg/dl; 95% CI -0.09 to -0.02 mg/dl; P=0.005). Meanwhile, the use of statins resulted in trends of reduced risks of renal replacement therapy and all-cause death within 30 days (relative risk 0.44; 95% CI 0.18-1.08; P=0.07). Further analyses indicated that high-dose statins were more effective than low-dose statins in reducing the risk of CIN and that different types of statins showed similar effects in preventing CIN.

CONCLUSION

Pretreatment with statins before angiography is effective in preventing CIN and may reduce the risk of adverse clinical events. However, the optimal dose and duration for statin pretreatment are still unknown.

Short-Term High-Dose Vitamin E to Prevent Contrast Medium-Induced Acute Kidney Injury in Patients With Chronic Kidney Disease Undergoing Elective Coronary Angiography: A Randomized Placebo-Controlled Trial

Background

Contrast medium–induced acute kidney injury (CIAKI) is a leading cause of acquired renal impairment. The effects of antioxidants have been conflicting regarding the prevention of CIAKI. We performed a study of vitamin E use to decrease CIAKI in patients undergoing elective coronary angiography.

Methods and Results

In a placebo‐controlled randomized trial at 2 centers in Iran, 300 patients with chronic kidney disease—defined as estimated glomerular filtration rate <60 mL/min per 1.73 m²—were randomized 1:1 to receive 0.9% saline infusion 12 hours prior to and after intervention combined with 600 mg vitamin E 12 hours before plus 400 mg vitamin E 2 hours before coronary angiography or to receive placebo. The primary end point was the development of CIAKI, defined as an increase ≥0.5 mg/dL or ≥25% in serum creatinine that peaked within 72 hours. Based on an intention‐to‐treat analysis, CIAKI developed in 10 (6.7%) and 21 (14.1%) patients in the vitamin E and placebo groups, respectively (P=0.037). Change in white blood cell count from baseline to peak value was greater in the vitamin E group compared with the placebo group (−500 [−1500 to 200] versus 100 [−900 to 600]×10³/mL, P=0.001). In multivariate analysis, vitamin E (odds ratio 0.408, 95% CI 0.170–0.982, P=0.045) and baseline Mehran score (odds ratio 1.257, 95% CI 1.007–1.569; P=0.043) predicted CIAKI.

Conclusions

Prophylactic short‐term high‐dose vitamin E combined with 0.9% saline infusion is superior to placebo for prevention of CIAKI in patients undergoing elective coronary angiography.

Clinical Trial Registration

URL: https://www.clinicaltrials.gov/. Unique identifier: NCT02070679.

N-acetylcysteine reduces the renal oxidative stress and apoptosis induced by hemorrhagic shock

BACKGROUND

Renal ischemia/reperfusion injury induced by hemorrhagic shock (HS) and subsequent fluid resuscitation is a common cause of acute renal failure. The objective of this study was to evaluate the effect of combining N-acetylcysteine (NAC) with fluid resuscitation on renal injury in rats that underwent HS.

MATERIALS AND METHODS

Two groups of male Wistar rats were induced to controlled HS at 35 mm Hg mean arterial pressure for 60 min. After this period, the HS and fluid resuscitation (HS/R) group was resuscitated with lactate containing 50% of the blood that was withdrawn. The HS/R + NAC group was resuscitated with Ringer's lactate combined with 150 mg/kg of NAC and blood. The sham group animals were catheterized but were not subjected to shock. All animals were kept under anesthesia and euthanized after 120 min of fluid resuscitation or observation.

RESULTS

Animals treated with NAC presented attenuation of histologic lesions, reduced oxidative stress, and apoptosis markers when compared with animals from the HS/R group. The serum creatinine was similar in all the groups.

CONCLUSIONS

NAC is a promising drug for combining with fluid resuscitation to attenuate the kidney injury associated with HS.

Preventing Contrast-induced Renal Failure: A Guide

Contrast-induced acute kidney injury (CI-AKI) is characterised by a rapid deterioration of renal function within a few days of parenteral administration of contrast media (CM) in the absence of alternative causes. CI-AKI is the most common form of iatrogenic kidney dysfunction with an estimated prevalence of 12 % in patients undergoing percutaneous coronary intervention. Although usually self-resolving, in patients with pre-existing chronic kidney disease (CKD) or concomitant risk factors for renal damage, CI-AKI is associated with increased short-and long-term morbidity and mortality. Therefore, risk stratification based on clinical and peri-procedural characteristics is crucial in selecting patients at risk of CI-AKI who would benefit the most from implementation of preventive measures.

Therapeutic Targets of Human AKI: Harmonizing Human and Animal AKI

The opportunity to make advances in the prevention and treatment of AKI has never been greater than it is today. Major advances have been made in the understanding of the biology of AKI, the design of clinical trials, and the use of diagnostic and prognostic biomarkers. These advances have been supplemented by the coordinated effort of societies, federal agencies, and industry, such that we are poised in the ensuing years to positively address the unrelenting harm that this disorder has created. Over the past decade, major advances have been made in understanding the pathophysiology of AKI, mainly through the study of small animal models. However, translating these findings to human AKI remains a barrier, which is typified by the absence of effective therapeutic agents. The purpose of the Acute Dialysis Quality Initiative (ADQI) XIII was to harmonize human and animal studies and determine what is known about potential therapeutic targets and what gaps in knowledge remain. A series of invited reviews will distill key concepts from this initiative that focus on different pathogenic features of AKI, including hemodynamics, immunity and inflammation, cellular and molecular pathways, progression, and regeneration and repair. This series will convey the status of our knowledge of the pathophysiology of human AKI and propose therapeutic targets for further investigation.

N-acetylcysteine for the prevention of contrast-induced nephropathy in patients with pre-existing renal insufficiency or diabetes: a systematic review and meta-analysis

PURPOSE

To identify benefit of N-acetylcysteine (NAC) on patients with pre-existing renal insufficiency or diabetes.

BACKGROUND

NAC administration is a common method for prevention of contrast-induced nephropathy (CIN). Nevertheless, its benefit on patients with pre-existing renal insufficiency or diabetes remains uncertain and controversial.

METHODS

Randomized controlled trials (RCTs) to evaluate the efficacy of NAC for the prevention of CIN in patients with pre-existing renal insufficiency or diabetes were searched from the databases of MEDLINE, EMBASE, and Cochrane library. Pooled odds ratio (OR) with 95% confidence interval (95% CI) were calculated using fixed-effects model by the Mantel-Haenszel test.

RESULTS

Twenty RCTs involving 3466 subjects (1756 assigned to NAC and 1710 assigned to the control) were included in the pre-existing renal dysfunction group. Pooled analysis suggested a significant reduction in CIN among this group (OR, 0.76; 95% CI, 0.61-0.93; p = 0.008). However, the nine trials comparing NAC versus control among patients with diabetes (NAC, 367 subjects; control, 358 subjects) showed no benefit of NAC for prevention of CIN (OR = 0.87; 95% CI, 0.58-1.30; p = 0.50). No significant heterogeneity was detected (p = 0.07; I2 = 34% for the group of pre-existing renal dysfunction; p = 0.40; I2 = 5% for the group of diabetes).

CONCLUSION

Our results suggest that NAC decreases the incidence of contrast-induced nephropathy among patients with pre-existing renal insufficiency. The benefit was not existed in patients with diabetes.

Risk of Acute Kidney Injury, Dialysis, and Mortality in Patients With Chronic Kidney Disease After Intravenous Contrast Material Exposure

OBJECTIVE

To examine the effect of intravenous iodinated contrast material administration on the subsequent development of acute kidney injury (AKI), emergent dialysis, and short-term mortality using a propensity score-adjusted analysis of computed tomographic scan recipients with chronic kidney disease (CKD).

PATIENTS AND METHODS

In this institutional review board-approved retrospective study, all patients with CKD who received a contrast-enhanced (contrast group) or unenhanced (noncontrast group) computed tomographic scan from January 1, 2000, to August 1, 2013 were identified. Patients were subdivided into CKD stage III (baseline estimated glomerular filtration rate, 30-59 mL/min per 1.73 m(2)) and CKD stage IV-V (baseline estimated glomerular filtration rate, <30 mL/min per 1.73 m(2)) subgroups and separately underwent propensity score generation, stratification, and 1:1 matching. Rates of AKI, 30-day emergent dialysis, and mortality were compared between contrast and noncontrast groups. Sensitivity analyses examining only patients with stable prescan serum creatinine levels and incorporating intravenous fluid administration at the time of the CT scan into the model were also performed.

RESULTS

A total of 6902 patients (4496 CKD stage III, matched: 1220 contrast and 1220 noncontrast; 2086 CKD stage IV-V, matched: 491 contrast and 491 noncontrast) were included in the study. After propensity score adjustment, rates of AKI, emergent dialysis, and mortality were not significantly higher in the contrast group than in the noncontrast group in either CKD subgroup (CKD stage III: OR, 0.65-1.00; P<.001-.99 and CKD stage IV-V: OR, 0.93-2.33; P=.22-.99). Both sensitivity analyses revealed similar results.

CONCLUSION

Intravenous contrast material administration was not associated with an increased risk of AKI, emergent dialysis, and short-term mortality in a cohort of patients with diminished renal function.

Contrast-associated AKI in the critically ill: relevant or irrelevant?

PURPOSE OF REVIEW

Iodinated contrast media are frequently administered in ICU patients. Recent studies challenge the relevance of contrast media toxicity in ICU patients and relate occurrence of acute kidney injury to baseline characteristics and severity of illness.

RECENT FINDINGS

Various findings in studies with kidney biomarkers indicate the causal relationship between contrast media exposure and kidney damage. Contrast media exposure not only causes direct tubular damage and renal hypoperfusion but also initiates the formation of reactive oxygen species in its turn causing tissue damage. The route of administration determines the incidence of contrast-induced acute kidney injury with a higher incidence when contrast media are administered by intra-arterial route versus intravenous route. The impact of contrast-associated acute kidney injury on hospital length of stay, the need for renal replacement therapy and survival remains a matter of debate because of discrepancies between observational versus case-matched studies and limitations of the individual studies.

SUMMARY

There are diverse pathophysiologic mechanisms explaining the causal relationship between the administration of contrast media and the development of acute kidney injury. Some studies challenge the relevance of contrast media toxicity in ICU patients. However, limitations of the available studies in ICU patients preclude firm conclusions. A precautionary approach in the administration of contrast media is justified.

Efficacy of preventive interventions for iodinated contrast-induced acute kidney injury evaluated by intrarenal oxygenation as an early marker

OBJECTIVE

The objective of this study was to evaluate the effects of potential renoprotective interventions such as the administration of N-acetylcysteine (NAC; antioxidant) and furosemide (diuretic) on intrarenal oxygenation as evaluated by blood oxygen level-dependent (BOLD) magnetic resonance imaging (MRI) in combination with urinary neutrophil gelatinase-associated lipocalin (NGAL) measurements.

MATERIALS AND METHODS

Rats received nitric oxide synthase inhibitor L-NAME (10 mg/kg) and cyclooxygenase inhibitor indomethacin (10 mg/kg) to induce the risk for developing iodinated contrast-induced acute kidney injury before receiving one of the interventions: NAC, furosemide, or placebo. One of the 3 iodinated contrast agents (iohexol, ioxaglate, or iodixanol) was then administered (1600-mg organic iodine per kilogram body weight). Fifty-four Sprague-Dawley rats were allocated in a random order into 9 groups on the basis of the intervention and the contrast agent received.Blood-oxygen-level-dependent MRI-weighted images were acquired on a Siemens 3.0-T scanner using a multiple gradient recalled echo sequence at baseline, after L-NAME, indomethacin, interventions or placebo, and iodinated contrast agents. Data acquisition and analysis were performed in a blind fashion. R2* (=1/T2*) maps were generated inline on the scanner. A mixed-effects growth curve model with first-order autoregressive variance-covariance was used to analyze the temporal data. Urinary NGAL, a marker of acute kidney injury, was measured at baseline, 2 and 4 hours after the contrast injection.

RESULTS

Compared with the placebo-treated rats, those treated with furosemide showed a significantly lower rate of increase in R2* (P < 0.05) in the renal inner stripe of the outer medulla. The rats treated with NAC showed a lower rate of increase in R2* compared with the controls, but the difference did not reach statistical significance. Urinary NGAL showed little to no increase in R2* after administration of iodixanol in the rats pretreated with furosemide but demonstrated significant increase in the rats pretreated with NAC or placebo (P < 0.05).

CONCLUSIONS

This is the first study to evaluate the effects of interventions to mitigate the deleterious effects of contrast media using BOLD MRI. The rate of increase in R2* after administration of iodinated contrast is associated with acute renal injury as evaluated by NGAL. Further studies are warranted to determine the optimum dose of furosemide and NAC for mitigating the ill effects of contrast media. Because NGAL has been shown to be useful in humans to document iodinated contrast-induced acute kidney injury, the method presented in this study using BOLD MRI and NGAL measurements can be translated to humans.

Contrast-Induced Nephropathy: Identifying the Risks, Choosing the Right Agent, and Reviewing Effective Prevention and Management Methods

With the rise in the use of intravenous iodinated contrast media for both computed tomography scan and angiographic studies, there is a greater likelihood of complications. One of the most well-known adverse effects is contrast-induced media nephropathy, which is also called contrast-induced acute kidney injury. This is third most common cause of hospital acquired acute renal failure. It is associated with an increase in morbidity, mortality, and greater financial burden on healthcare system. Because of these factors, it is important for the radiologist to not only recognize risk factors, as well as the signs and symptoms, but also to know how to manage patients appropriately.

Present and future in the treatment of diabetic kidney disease

Diabetic kidney disease is the leading cause of end-stage renal disease. Albuminuria is recognized as the most important prognostic factor for chronic kidney disease progression. For this reason, blockade of renin-angiotensin system remains the main recommended strategy, with either angiotensin converting enzyme inhibitors or angiotensin II receptor blockers. However, other antiproteinuric treatments have begun to be studied, such as direct renin inhibitors or aldosterone blockers. Beyond antiproteinuric treatments, other drugs such as pentoxifylline or bardoxolone have yielded conflicting results. Finally, alternative pathogenic pathways are being explored, and emerging therapies including antifibrotic agents, endothelin receptor antagonists, or transcription factors show promising results. The aim of this review is to explain the advances in newer agents to treat diabetic kidney disease, along with the background of the renin-angiotensin system blockade.

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

OBJECTIVE

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

CONCLUSION

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

Incidence, prognostic impact, and optimal definition of contrast-induced acute kidney injury in consecutive patients with stable or unstable coronary artery disease undergoing percutaneous coronary intervention. insights from the all-comer PRODIGY trial

BACKGROUND

Contrast-induced acute kidney injury (CI-AKI) is associated with poor outcome. Whether this association differs in stable coronary artery disease (CAD) as compared to acute coronary syndrome (ACS) patients is unknown. Definitions and Methods: PRODIGY trial patients were defined as stable CAD or ACS according to the initial presentation. CI-AKI was defined as an increase (Δ) of serum creatinine (SCr) ≥25% above baseline. Two endpoints were considered: all-cause death and the composite of death, stroke, or myocardial infarction (MI). The interaction between CI-AKI, clinical setting, and the impact of increasing ΔSCr% cut-offs were also explored.

RESULTS

Two thousand three patients were enrolled in the PRODIGY trial, 85 patients were excluded for missing SCr data, leading to a population of 1,918 patients. CI-AKI incidence was 6.7% in stable CAD and 12.2% in ACS patients. CI-AKI was associated with all-cause mortality [adjusted hazard ratio (aHR) of 2.05, 95% confidence interval (CI) 1.38-3.05, P < 0.001] and the composite of death, stroke, or MI [aHR of 1.49, 95% CI 1.13-1.97, P < 0.001]. The risk of CI-AKI for the composite endpoint was higher in stable CAD, P for interaction: 0.048. A ΔSCr of 35% was associated with the highest aHR for all-cause mortality: 2.34 [95% CI, 1.46-3.76, P < 0.001] and the composite of death, stroke, or MI: 1.70 [95% CI, 1.20-2.40, P > 0.001].

CONCLUSIONS

In a large, contemporary, all-comers percutaneous coronary intervention population, CI-AKI was associated with an increased risk of all-cause death and the composite of death, stroke, or MI. While CI-AKI is more common in ACS than in stable CAD patients, its adjusted prognostic impact on the composite endpoint appears to be more pronounced in patients with stable CAD.

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.

Intravascular ultrasound guidance to minimize the use of iodine contrast in percutaneous coronary intervention: the MOZART (Minimizing cOntrast utiliZation With IVUS Guidance in coRonary angioplasTy) randomized controlled trial

OBJECTIVES

The aim of this study was to evaluate the impact of intravascular ultrasound (IVUS) guidance on the final volume of contrast agent used in patients undergoing percutaneous coronary intervention (PCI).

BACKGROUND

To date, few approaches have been described to reduce the final dose of contrast agent in PCIs. We hypothesized that IVUS might serve as an alternative imaging tool to angiography in many steps during PCI, thereby reducing the use of iodine contrast.

METHODS

A total of 83 patients were randomized to angiography-guided PCI or IVUS-guided PCI; both groups were treated according to a pre-defined meticulous procedural strategy. The primary endpoint was the total volume contrast agent used during PCI. Patients were followed clinically for an average of 4 months.

RESULTS

The median total volume of contrast was 64.5 ml (interquartile range [IQR]: 42.8 to 97.0 ml; minimum, 19 ml; maximum, 170 ml) in the angiography-guided group versus 20.0 ml (IQR: 12.5 to 30.0 ml; minimum, 3 ml; maximum, 54 ml) in the IVUS-guided group (p < 0.001). Similarly, the median volume of contrast/creatinine clearance ratio was significantly lower among patients treated with IVUS-guided PCI (1.0 [IQR: 0.6 to 1.9] vs. 0.4 [IQR: 0.2 to 0.6, respectively; p < 0.001). In-hospital and 4-month outcomes were not different between patients randomized to angiography-guided and IVUS-guided PCI.

CONCLUSIONS

Thoughtful and extensive use of IVUS as the primary imaging tool to guide PCI is safe and markedly reduces the volume of iodine contrast compared with angiography-alone guidance. The use of IVUS should be considered for patients at high risk of contrast-induced acute kidney injury or volume overload undergoing coronary angioplasty. (Minimizing cOntrast utiliZation With IVUS Guidance in coRonary angioplasTy [MOZART]; NCT01947335).

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.

Contrast-Induced Nephropathy

Contrast-induced nephropathy (CIN) represents an important adverse effect of contrast media (CM) administration. Contrast-induced nephropathy is associated with prolonged hospitalization as well as increased cardiovascular morbidity, renal morbidity, and all-cause mortality. Several risk factors may predict CIN incidence, and various scores and ratios have been proposed to identify high-risk patients. Novel biomarkers may provide an earlier diagnosis of CIN. A multifactorial approach is required for CIN prevention including hydration, administration of low- or iso-osmolar CM, minimizing CM volume, and statin administration. Renal function may deteriorate after CM administration, even in the absence of CIN. Therefore, this deterioration may not be an “all or none” phenomenon; it may well occur in many patients receiving CM, with/without CIN, and may prove to be an underestimated risk factor. Patients should be followed up for longer periods as outpatients after CM exposure to assess kidney function and predict subsequent increased morbidity and mortality.