Prophylactic hydration to protect renal function from intravascular iodinated contrast material in patients at high risk of contrast-induced nephropathy (AMACING): a prospective, randomised, phase 3, controlled, open-label, non-inferiority trial

[Contrast medium-induced acute kidney injury-Consensus paper of the working group "Heart and Kidney" of the German Cardiac Society and the German Society of Nephrology]

This consensus paper summarizes the expert consensus and recommendations of the working group "Heart and Kidney" of the German Cardiac Society (DGK) and the German Society of Nephrology (DGfN) on contrast medium-induced acute kidney injury. Potentially nephrotoxic contrast agents containing iodine are frequently used in interventional medicine and for computer tomography diagnostics. Acute kidney injury occurs in approximately 8-17% of patients exposed to contrast media. The risk factors and underlying pathophysiology are discussed and recommendations for the prophylaxis and treatment of contrast medium-induced acute nephropathy are presented.

A Novel Antioxidant Protects Against Contrast Medium-Induced Acute Kidney Injury in Rats

Many studies proposed that oxidative stress and apoptosis are key mechanisms in the pathogenesis of contrast-induced acute kidney injury (CI-AKI). Xylose-pyrogallol conjugate (XP) is an original effective antioxidant that showed decent antioxidant and anti-apoptosis effect before. Thus the therapeutic effect and mechanism of XP in preventing CI-AKI in the short and long term were investigated in this research. Renal function and histological grade were evaluated to determine the severity of renal injury. Kidney samples were then collected for the measurement of oxidative stress markers and the detection of apoptosis. Transmission electron microscopy (TEM) and western blot of mitochondrial protein were utilized for the analysis of the mitochondrial conditions. The results demonstrated that the CI-AKI rats caused a significant decrease in renal function accompanied by a remarkable increase in Malondialdehyde (MDA), bax, caspase-3, cytochrome c (Cyt C) level, TdT-mediated dUTP nick end labeling (TUNEL) positive apoptotic cells, and damaged mitochondria, while a decline in antioxidase activities and mitochondrial superoxide dismutase 2 (SOD2) expression compared with the control rats. However, when XP (50 or 100 or 200 mg/kg/day) was given orally for consecutive 7 days before CI-AKI modeling, XP (200 mg/kg) showed a better capability to restore renal dysfunction, histopathological appearance, the level of apoptosis, mitochondrial damage, oxidative stress, and fibrosis generation without interference in computed tomographic imaging. Our study indicated that antioxidant XP played a nephroprotective role probably via antiapoptotic and antioxidant mechanisms. Besides, XP may regulate the mitochondria pathway via decreasing the ratio of bax/bcl-2, inhibiting caspase-3 expression, cytochrome c release, and superoxide dismutase 2 activity. Overall, XP as a high-efficient antioxidant may have the potentials to prevent CI-AKI.

Post-Contrast Acute Kidney Injury and Intravenous Prophylactic Hydration: An Update

BACKGROUND

 Despite tremendous improvement in molecular properties over the last century, intravascular injection of iodinated contrast material may still have systemic and hemodynamic consequences. Patients with pre-existing renal insufficiency may be at risk for acute kidney injury, which may be associated with an increased risk of the need for dialysis and mortality in the long term. Many questions as to the physiological pathways, optimal definition, and incidence of contrast-induced acute kidney injury remain open. These uncertainties are reflected in the changing landscape of this field in terms of nomenclature, research, and clinical practice.

METHODS

 Clinical practice guidelines for the prevention of post-contrast acute kidney injury all recommend giving prophylaxis in the form of intravenous hydration to high-risk patients. Solid evidence for this strategy is lacking. This article gives an overview of the changing landscape of post-contrast acute kidney injury and prophylactic intravenous hydration, with the aim of supporting informed decision-making in clinical practice.

RESULTS

 Recent data have caused a shift in guideline recommendations: 90 % of patients formerly considered high-risk for contrast-induced acute kidney injury no longer qualify for prophylaxis. The remaining high-risk patients, with severe chronic kidney disease, represent a vulnerable population for whom intravenous hydration may provide some benefits but also carries risk.

CONCLUSION

 Intravenous hydration may benefit 'new' high-risk patients. However, it also confers risk. A dual approach to screening patients will help avoid this risk in clinical practice.

KEY POINTS

  · Intravenous hydration is the cornerstone for preventing contrast-induced acute kidney injury. · Solid evidence is lacking; recent data caused a shift in guideline recommendations. · Intravenous hydration may benefit 'new' high-risk patients with severe chronic kidney disease; however, it also confers risk. · A dual approach to screening patients will help avoid this risk in clinical practice.

CITATION FORMAT

· Nijssen E, Rennenberg R, Nelemans P et al. Post-Contrast Acute Kidney Injury and Intravenous Prophylactic Hydration: An Update. Fortschr Röntgenstr 2021; 193: 151 - 159.

Iodinated contrast medium: Is there a re(n)al problem? A clinical vignette-based review

As we were taught, for decades, that iodinated contrast-induced acute kidney injury should be dreaded, considerable efforts were made to find out effective measures in mitigating the renal risk of iodinated contrast media. Imaging procedures were frequently either downgraded (unenhanced imaging) or deferred as clinicians felt that the renal risk pertaining to contrast administration outweighed the benefits of an enhanced imaging. However, could we have missed the point? Among the abundant literature about iodinated contrast-associated acute kidney injury, recent meaningful advances may help sort out facts from false beliefs. Hence, there is increasing evidence that the nephrotoxicity directly attributable to modern iodinated CM has been exaggerated. Failure to demonstrate a clear benefit from most of the tested prophylactic measures might be an indirect consequence. However, the toxic potential of iodinated contrast media is well established experimentally and should not be overlooked completely when making clinical decisions. We herein review these advances in disease and pathophysiologic understanding and the associated clinical crossroads through a typical case vignette in the critical care setting.

Long-term renal outcomes after elective percutaneous coronary intervention in patients with advanced renal dysfunction

The aim of the present study was to evaluate the renal outcomes, including the time course of renal function, after elective PCI in patients with advanced renal dysfunction and to assess the predictors of renal dysfunction progression. This is a subanalysis of a previous observational multicenter study that investigated long-term clinical outcomes in patients with advanced renal dysfunction (eGFR < 30 mL/min/1.73 m²), focusing on 151 patients who underwent elective PCI and their long-term renal outcomes. Renal dysfunction progression was defined as a 20% relative decrease in eGFR at 1 year from baseline or the initiation of permanent dialysis within 1 year. Progression of renal dysfunction at 1 year occurred in 42 patients (34.1%). Among patients with renal dysfunction progression, the decrease of renal function from baseline was not observed at 1 month but after 6 months of the index PCI. Baseline eGFR and serum albumin level were significant predictors of renal dysfunction progression at 1 year. Among 111 patients who had not been initiated on dialysis within 1 year, those with renal dysfunction progression had a significantly higher incidence of dialysis initiation more than 1 year after the index PCI than those with preserved renal function (p < 0.001). Among patients with advanced renal dysfunction who underwent elective PCI, 34.1% showed renal dysfunction progression at 1 year. The decrease in renal function was not observed at 1 month but after 6 months of the index PCI in patients with renal dysfunction progression. Furthermore, patients with renal dysfunction progression had poorer long-term renal outcomes.

KDIGO Controversies Conference on onco-nephrology: understanding kidney impairment and solid-organ malignancies, and managing kidney cancer

The association between kidney disease and cancer is multifaceted and complex. Persons with chronic kidney disease (CKD) have an increased incidence of cancer, and both cancer and cancer treatments can cause impaired kidney function. Renal issues in the setting of malignancy can worsen patient outcomes and diminish the adequacy of anticancer treatments. In addition, the oncology treatment landscape is changing rapidly, and data on tolerability of novel therapies in patients with CKD are often lacking. Caring for oncology patients has become more specialized and interdisciplinary, currently requiring collaboration among specialists in nephrology, medical oncology, critical care, clinical pharmacology/pharmacy, and palliative care, in addition to surgeons and urologists. To identify key management issues in nephrology relevant to patients with malignancy, KDIGO (Kidney Disease: Improving Global Outcomes) assembled a global panel of multidisciplinary clinical and scientific expertise for a controversies conference on onco-nephrology in December 2018. This report covers issues related to kidney impairment and solid organ malignancies as well as management and treatment of kidney cancer. Knowledge gaps, areas of controversy, and research priorities are described.

Comparison of acute kidney injury with radial vs. femoral access for patients undergoing coronary catheterization: An updated meta-analysis of 46,816 patients

Trans-radial access for percutaneous coronary intervention or angiography has gained popularity amongst interventional cardiologists. Radial access is also thought to reduce the incidence of acute kidney injury (AKI) in the immediate post-operative period. The purpose of the present study was to perform a comprehensive updated systematic review and meta-analysis comparing the incidence of AKI following the radial vs. femoral route of coronary catheterization. An electronic literature search of the PubMed, BioMed Central, Scopus, Cochrane Central Register of Controlled Trials and Google Scholar databases up to 1st January 2020 was performed. A total of 14 studies were included, 2 of which were randomized controlled trials (RCTs), and 6 studies utilized propensity score matching. Comparison of the data of 21,479 patients in the radial group and 25,337 patients in the femoral group indicated a reduced incidence of AKI with the radial route [odds ratio (OR):0.66, 95% CI: 0.54-0.81, P<0.0001, I2=74%]. Similar results were obtained with sub-group analyses for RCTs (OR: 0.87, 95% CI: 0.77-0.98, P=0.02, I2=0%), retrospective studies (OR: 0.57, 95% CI: 0.36-0.90, P=0.02, I2=86%) and propensity score-matched studies (OR: 0.63, 95% CI: 0.48-0.83, P=0.0009, I2=45%). Multivariable-adjusted ORs of AKI for the radial vs. femoral route were extracted from non-RCTs and pooled for a meta-analysis, which also demonstrated similar results (OR: 0.70, 95% CI: 0.57-0.88, P=0.002, I2=70%). Within the limitations of the study, the present results indicate that, as compared to femoral access, the use of trans-radial access for coronary catheterization is associated with a significantly reduced incidence of AKI. A reduction of AKI by ~34% may be expected with the use of radial access.

Multidetector computed tomography in transcatheter aortic valve replacement: an update on technological developments and clinical applications

INTRODUCTION

Transcatheter aortic valve replacement (TAVR) has revolutionized the treatment of patients with underlying sever aortic valve stenosis across all spectrum of the disease. CT imaging is so crucial to the pre procedural planning, to incorporate the information from the CT imaging in the decision making intraprocedurally and to predict and identity the post procedural complications.Areas covered: In this article, we review available studies on CT role in TAVR procedure and provide update on the technological developments and clinical applications.Expert opinion: CT imaging, with its high resolution, and in particular its utilization in aortic annular measurements, bicuspid aortic valve assessment, hypoattenuated leaflet thickening and valve in valve therapy proved to be the ideal approach to study the mechanisms of aortic stenosis, detection of high-risk anatomy, more accurate risk stratification and thus to allow a personalized catheter based intervention of the affected patients.

Trimetazidine can prevent the occurrence of contrast-induced nephropathy after percutaneous coronary intervention in elderly patients with renal insufficiency

BACKGROUND

Contrast-induced nephropathy (CIN) has become a common cause of hospital-acquired acute kidney injury in elderly patients. Trimetazidine (TMZ) is a type of anti-ischemic drug developed in recent years, which can reduce the incidence of CIN. This study aimed to evaluate the efficacy of TMZ in the prevention of contrast-induced nephropathy in elderly patients with renal insufficiency undergoing percutaneous coronary intervention (PCI) and to explore the mechanism of action.

METHODS

A total of 310 elderly patients with renal insufficiency undergoing elective PCI were enrolled and randomly assigned to a control group (n = 155, hydration only) and a TMZ group (n = 155, 20 mg thrice daily orally 24 hours before and 72 hours after PCI). The primary endpoint of the study was the incidence of CIN, which was defined as an increase of 25% or more, or an absolute increase of 0.5 mg/dL or more in serum creatinine from baseline value, at 48 to 72 hours following the exposure to contrast media (CM).

RESULTS

The incidence of CIN was significantly lower in the TMZ group than that in the control group (3.2% vs. 9.7%, p = 0.021). There was no difference regarding the incidence of major adverse events during hospitalization between the TMZ group and control group (1.9% vs. 2.6%, p = 1.000). Binary logistic regression results showed that TMZ was protective factors of CIN (OR = 0.274; 95% CI: 0.089-0.847; p = 0.025).

CONCLUSION

Therefore, we came to the conclusion that prophylactic administration of TMZ can prevent the occurrence of CIN in elderly patients with renal insufficiency undergoing PCI and has a certain protective effect on the renal function of patients. According to the experimental results and the mechanism of TMZ on cardiomyocytes, we speculate that TMZ increases kidney glucose metabolism, reduces fatty acid oxidation, and also has a protective effect on kidney free radical damage and ischemia-reperfusion injury.

Tailoring Contrast Media Protocols to Varying Tube Voltages in Vascular and Parenchymal CT Imaging: The 10-to-10 Rule

The latest technical developments in CT have created the possibility for individualized scan protocols at variable kV settings. Lowering tube voltages closer to the K-edge of iodine increases attenuation. However, the latter is also influenced by patient characteristics such as total body weight. To maintain a robust contrast enhancement throughout the patient population in both vascular and parenchymal CT scans, one must adapt the contrast media administration protocols to both the selected kV setting and patient body habitus. This article proposes a simple rule of thumb for how to adapt the contrast media protocol to any kV setting: the 10-to-10 rule.

A Comparison of Biannual Two-Phase Low-Dose Liver CT and US for HCC Surveillance in a Group at High Risk of HCC Development

BACKGROUND AND AIMS

Biannual ultrasonography (US) is a current recommendation for hepatocellular carcinoma (HCC) surveillance in a high-risk group. The sensitivity of US, however, has been low in patients with a high risk of developing HCC. We aimed to compare sensitivity for HCC of biannual US and two-phase low-dose computed tomography (LDCT) in patients with a high risk of HCC.

METHODS

In this prospective single-arm study, participants with an annual risk of HCC greater than 5% (based on a risk index of ≥2.33) and who did not have a history of HCC were enrolled from November 2014 to July 2016. Participants underwent paired biannual US and two-phase LDCT 1-3 times. Two-phase LDCT included arterial and 3-min delayed phases. The sensitivity, specificity, and positive predictive value of HCC detection using US and two-phase LDCT were compared using a composite algorithm as a standard of reference.

RESULTS

Of the 139 enrolled participants, 137 underwent both the biannual US and two-phase LDCT at least once and had follow-up images. Among them, 27 cases of HCC (mean size: 14 ± 4 mm) developed in 24 participants over 1.5 years. Two-phase LDCT showed a significantly higher sensitivity (83.3% [20/24] vs. 29.2% [7/24], p < 0.001) and specificity (95.6% [108/113] vs. 87.7% [99/113], p =0.03) than US. A false-positive result was reported in 14 participants at US and 5 participants at two-phase LDCT, resulting in a significantly higher positive predictive value of two-phase LDCT (33.3% [7/21] vs. 80% [20/25], p < 0.001).

CONCLUSIONS

Patients with a risk index ≥2.33 showed a high annual incidence of HCC development in our study, and two-phase LDCT showed significantly higher sensitivity and specificity for HCC detection than US.

A prediction model of contrast-associated acute kidney injury in patients with hypoalbuminemia undergoing coronary angiography

BACKGROUND

Risk stratification is recommended as the key step to prevent contrast-associated acute kidney injury (CA-AKI) among at-risk patients following coronary angiography (CAG) and/or percutaneous coronary intervention (PCI). Patients with hypoalbuminemia are prone to CA-AKI and do not have their own risk stratification tool. Therefore, this study developed and validated a new model for predicting CA-AKI among hypoalbuminemia patients CAG/PCI.

METHODS

1272 patients with hypoalbuminemia receiving CAG/PCI were enrolled and randomly allocated (2:1 ratio) into the development cohort (n = 848) and the validation cohort (n = 424). CA-AKI was defined as an increase of ≥0.3 mg/dL or 50% in serum creatinine (SCr) compared to baseline in the 48 to 72 h after CAG/PCI. A prediction model was established with independent predictors according to stepwise logistic regression, showing as a nomogram. The discrimination of the new model was evaluated by the area under the curve (AUC) and was compared to the classic Mehran CA-AKI model. The Hosmer-Lemeshow test was conducted to assess the calibration of our model.

RESULTS

Overall, 8.4% (71/848) patients of the development group and 11.2% (48/424) patients of the validation group experienced CA-AKI. A new nomogram included estimated glomerular filtration rate (eGFR), serum albumin (ALB), age and the use of intra-aortic balloon pump (IABP); showed better predictive ability than the Mehran score (C-index 0.756 vs. 0.693, p = 0.02); and had good calibration (Hosmer-Lemeshow test p = 0.187).

CONCLUSIONS

We developed a simple model for predicting CA-AKI among patients with hypoalbuminemia undergoing CAG/PCI, but our findings need validating externally.

TRIAL REGISTRATION

http://www.ClinicalTrials.gov NCT01400295 , retrospectively registered 21 July 2011.

CaMKII as a key regulator of contrast-induced nephropathy through mPTP opening in HK-2 cells

Contrast-induced nephropathy (CIN), refers to acute kidney injury observed after administration of contrast media during angiographic or other medical procedures such as urography, and accounting for 12% of all causes of acute renal failure, but no specific prevention or treatment strategy exists for its obscure pathophysiology. The aim of our study was to explore the influence of calcium/calmodulin-dependent protein kinase II (CaMKII) in CIN by using HK-2 cells. Knockdown of CypD was achieved by lentivirus, and CaMKII overexpression by transfection with the plasmid. In this study, we have demonstrated that CypD-mediated mPTP opening triggered mitochondrial dysfunction and tubule cells apoptosis in CIN. We also found that iohexol treatment was associated with mitochondrial ROS overloading, ATP depletion and LDH release. Inhibition of CypD with the pharmacologic inhibitor or knockdown of CypD abrogated mPTP opening, oxidative stress, mitochondria damage, and cell apoptosis induced by iohexol. In addition, we found that inhibition of the CaMKII activity alleviated iohexol-induced CypD expression, whereas also decreased mPTP opening, oxidative stress, mitochondria damage, and cell apoptosis, similarly to the inhibition of CypD did. Moreover, CaMKII overexpression enhanced iohexol-induced mPTP opening, mitochondrial damage and renal tubular epithelial cells apoptosis. These findings first identified the novel role of CaMKII in iohexol-induced tubular cells apoptosis and delineated the CaMKII-CypD/mPTP pathway during contrast-induced tubular cell damage. Hence, these results could provide a new strategy for CIN protection.

Controversies in acute kidney injury: conclusions from a Kidney Disease: Improving Global Outcomes (KDIGO) Conference

In 2012, Kidney Disease: Improving Global Outcomes (KDIGO) published a guideline on the classification and management of acute kidney injury (AKI). The guideline was derived from evidence available through February 2011. Since then, new evidence has emerged that has important implications for clinical practice in diagnosing and managing AKI. In April of 2019, KDIGO held a controversies conference entitled Acute Kidney Injury with the following goals: determine best practices and areas of uncertainty in treating AKI; review key relevant literature published since the 2012 KDIGO AKI guideline; address ongoing controversial issues; identify new topics or issues to be revisited for the next iteration of the KDIGO AKI guideline; and outline research needed to improve AKI management. Here, we present the findings of this conference and describe key areas that future guidelines may address.

Point-of-care creatinine tests to assess kidney function for outpatients requiring contrast-enhanced CT imaging: systematic reviews and economic evaluation

BACKGROUND

Patients with low estimated glomerular filtration rates may be at higher risk of post-contrast acute kidney injury following contrast-enhanced computed tomography imaging. Point-of-care devices allow rapid measurement of estimated glomerular filtration rates for patients referred without a recent estimated glomerular filtration rate result.

OBJECTIVES

To assess the clinical effectiveness and cost-effectiveness of point-of-care creatinine tests for outpatients without a recent estimated glomerular filtration rate measurement who need contrast-enhanced computed tomography imaging.

METHODS

Three systematic reviews of test accuracy, implementation and clinical outcomes, and economic analyses were carried out. Bibliographic databases were searched from inception to November 2018. Studies comparing the accuracy of point-of-care creatinine tests with laboratory reference tests to assess kidney function in adults in a non-emergency setting and studies reporting implementation and clinical outcomes were included. Risk of bias of diagnostic accuracy studies was assessed using a modified version of the Quality Assessment of Diagnostic Accuracy Studies 2 (QUADAS-2) tool. Probabilities of individuals having their estimated glomerular filtration rates correctly classified were estimated within a Bayesian framework and pooled using a fixed-effects model. A de novo probabilistic decision tree cohort model was developed to characterise the decision problem from an NHS and a Personal Social Services perspective. A range of alternative point-of-care testing approaches were considered. Scenario analyses were conducted.

RESULTS

Fifty-four studies were included in the clinical reviews. Twelve studies reported diagnostic accuracy for estimated glomerular filtration rates; half were rated as being at low risk of bias, but there were applicability concerns for most. i-STAT (Abbott Point of Care, Inc., Princeton, NJ, USA) and ABL (Radiometer Ltd, Crawley, UK) devices had higher probabilities of correctly classifying individuals in the same estimated glomerular filtration rate categories as the reference laboratory test than StatSensor® devices (Nova Biomedical, Runcorn, UK). There was limited evidence for epoc® (Siemens Healthineers AG, Erlangen, Germany) and Piccolo Xpress® (Abaxis, Inc., Union City, CA, USA) devices and no studies of DRI-CHEM NX 500 (Fujifilm Corporation, Tokyo, Japan). The review of implementation and clinical outcomes included six studies showing practice variation in the management decisions when a point-of-care device indicated an abnormal estimated glomerular filtration rate. The review of cost-effectiveness evidence identified no relevant studies. The de novo decision model that was developed included a total of 14 strategies. Owing to limited data, the model included only i-STAT, ABL800 FLEX and StatSensor. In the base-case analysis, the cost-effective strategy appeared to be a three-step testing sequence involving initially screening all individuals for risk factors, point-of-care testing for those individuals with at least one risk factor, and including a final confirmatory laboratory test for individuals with a point-of-care-positive test result. Within this testing approach, the specific point-of-care device with the highest net benefit was i-STAT, although differences in net benefit with StatSensor were very small.

LIMITATIONS

There was insufficient evidence for patients with estimated glomerular filtration rates < 30 ml/minute/1.73 m2, and on the full potential health impact of delayed or rescheduled computed tomography scans or the use of alternative imaging modalities.

CONCLUSIONS

A three-step testing sequence combining a risk factor questionnaire with a point-of-care test and confirmatory laboratory testing appears to be a cost-effective use of NHS resources compared with current practice. The risk of contrast causing acute kidney injury to patients with an estimated glomerular filtration rate of < 30 ml/minute/1.73 m2 is uncertain. Cost-effectiveness of point-of-care testing appears largely driven by the potential of point-of-care tests to minimise delays within the current computed tomography pathway.

FUTURE WORK

Studies evaluating the impact of risk-stratifying questionnaires on workflow outcomes in computed tomography patients without recent estimated glomerular filtration rate results are needed.

STUDY REGISTRATION

This study is registered as PROSPERO CRD42018115818.

FUNDING

This project was funded by the National Institute for Health Research (NIHR) Health Technology Assessment programme and will be published in full in Health Technology Assessment; Vol. 24, No. 39. See the NIHR Journals Library website for further project information.

Effects of Remote Ischemic Pre-Conditioning to Prevent Contrast-Induced Nephropathy after Intravenous Contrast Medium Injection: A Randomized Controlled Trial

Objective

We aimed to assess the effects of remote ischemic pre-conditioning (RIPC) on the incidence of contrast-induced nephropathy (CIN) after an intravenous (IV) or intra-arterial injection of contrast medium (CM) in patient and control groups.

Materials and Methods

This prospective, randomized, single-blinded, controlled trial included 26 patients who were hospitalized for the evaluation of the feasibility of transcatheter aortic valve implantation and underwent investigations including contrast-enhanced computed tomography (CT), with Mehran risk scores greater than or equal to six. All the patients underwent four cycles of five minute-blood pressure cuff inflation followed by five minutes of total deflation. In the RIPC group (n = 13), the cuff was inflated to 50 mm Hg above the patient's systolic blood pressure (SBP); in the control group (n = 13), it was inflated to 10 mm Hg below the patient's SBP. The primary endpoint was the occurrence of CIN. Additionally, variation in the serum levels of cystatin C was assessed.

Results

One case of CIN was observed in the control group, whereas no cases were detected in the RIPC group (p = 0.48, analysis of 25 patients). Mean creatinine values at the baseline, 24 hours after injection of CM, and 48 hours after injection of CM were 88 ± 32 µmol/L, 91 ± 28 µmol/L and 82 ± 29 µmol/L, respectively (p = 0.73) in the RIPC group, whereas in the control group, they were 100 ± 36 µmol/L, 110 ± 36 µmol/L, and 105 ± 34 µmol/L, respectively (p = 0.78). Cystatin C values (median [Q1, Q3]) at the baseline, 24 hours after injection of CM, and 48 hours after injection of CM were 1.10 [1.08, 1.18] mg/L, 1.17 [0.97, 1.35] mg/L, and 1.12 [0.99, 1.24] mg/L, respectively (p = 0.88) in the RIPC group, whereas they were 1.11 [0.97, 1.28] mg/L, 1.13 [1.08, 1.25] mg/L, and 1.16 [1.03, 1.31] mg/L, respectively (p = 0.93), in the control group.

Conclusion

The risk of CIN after an IV injection of CM is very low in patients with Mehran risk score greater than or equal to six and even in the patients who are unable to receive preventive hyperhydration. Hence, the Mehran risk score may not be an appropriate method for the estimation of the risk of CIN after IV CM injection.

Biomarkers in the prediction of contrast media induced nephropathy - the BITCOIN study

Background

Subjects with chronic kidney disease are at increased risk for contrast-induced acute kidney injury (CI-AKI). Risk stratification is traditionally based on glomerular filtration rate (GFR) and proteinuria. The present trial examines, whether tubular and inflammatory biomarkers are able to identify subjects at increased risk as well.

Methods

We performed a prospective study in 490 patients undergoing coronary angiography. An increase of serum creatinine concentration ≥ 0.3 mg/dl from baseline to day 2–3 was defined as primary endpoint (CI-AKI). Urinary neutrophil gelatinase-associated lipocalin (NGAL), kidney injury molecule-1 (KIM-1), and calprotectin were assessed < 24h before coronary angiography. Prognostic accuracy was assessed by receiver operating characteristics (ROC) calculations.

Results

30 (6.1%) patients suffered from CI-AKI (27 AKIN stage I, 3 AKIN stage II, 0 AKIN stage III). Those subjects who developed CI-AKI had 3.1 fold higher baseline urinary NGAL/creatinine ratios than those without CI-AKI (60.8 [IQR 18.7–93.1] μg/mg vs. 19.9 [IQR 12.3–38.9] μg/mg, p = 0.001). In those subjects without clinically overt CKD (eGFR > 60 ml/min, urinary albumin creatinine ratio <30 mg/g), the NGAL/creatinine ratio was 2.6 higher in CI-AKI vs. no CI-AKI (47.8 [IQR 11.8–75.3] vs. 18.6 [IQR 11.7–36.3] μg/mg). No significant differences were obtained for KIM-1 and calprotectin (p>0.05 each). ROC analyses revealed an area under the curve (AUC) of 0.68 (95% CI 0.60–0.81) for NGAL/creatinine. An NGAL/creatinine ratio < 56.4 μg/mg has a negative predictive value of 96.5%.

Conclusions

The present study is the largest investigation on the use of urinary biomarkers for CI-AKI risk stratification so far. It shows that NGAL provides prognostic information beyond the glomerular biomarkers eGFR and proteinuria.

Hydration: Intravenous and Oral: Approaches, Principals, and Differing Regimens: Is It What Goes in or What Comes Out That Is Important?

The literature (in English) was accessed to review the evidence that administration of fluids is protective of contrast-associated acute kidney injury (CA-AKI). The evidence was evaluated with the intent of understanding mechanisms of protection. Prospective randomized trials comparing oral versus intravenous fluid, sodium chloride versus no intravenous fluid, sodium bicarbonate versus sodium chloride, and forced matched hydration versus intravenous sodium chloride provided the data. In general, the more fluid administered, the lower the incidence of CA-AKI. However, understanding the mechanism of this beneficial effect suggests that it is the urine output that most directly affects the incidence of CA-AKI.

Future of Diagnostic Computed Tomography: An Update on Physicochemical Properties, Safety, and Development of X-ray Contrast Media

Iodinated contrast media (CM) are utilized in approximately 40% of the 300 million computed tomography (CT) scans undertaken annually. This review focuses on the physicochemical properties and safety of iodinated CM, and the development of new x-ray CM, and it explores methods to optimize CT scanning parameters. It concludes that good x-ray CM should have high structural stability, hydrophilicity, and CT attenuation; low viscosity, osmolality, and protein binding; no metabolism and tissue accumulation; and a complete elimination.

Nomogram for contrast-induced acute kidney injury in patients with chronic kidney disease undergoing coronary angiography in China: a cohort study

OBJECTIVES

To establish a nomogram for contrast-induced acute kidney injury (CI-AKI) risk assessment among patients with chronic kidney disease (CKD) undergoing coronary angiography (CAG) or percutaneous coronary intervention (PCI).

DESIGN

Prospective observational cohort study.

SETTING

Southern China.

INTERVENTIONS

None.

PARTICIPANTS

643 consecutive patients with CKD (defined as estimated glomerular filtration rate calculated by Modification of Diet in Renal Disease formula <60 mL/min/1.73 mm2) were enrolled.

OUTCOME MEASURES

The end point was CI-AKI defined as serum creatinine elevation ≥0.5 mg/dL or 25% from baseline within the first 48-72 hours following contrast exposure.Predictors of CI-AKI were selected by multivariable logistic regression and stepwise approach. A nomogram based on these predictors was constructed and compared with the classic Mehran Score. For validation, a bootstrap method (1000 times) was performed.

RESULTS

The nomogram including age, weight, heart rate, hypotension, PCI and β-blocker demonstrated a better predictive value than the classic Mehran Score (area under the curve: 0.78 vs 0.71, p=0.024), as well as a well-fitted calibration curve (χ2=12.146, p=0.145). Validation through the bootstrap method (1000 times) also indicated a good discriminative power (adjusted C-statistic: 0.76).

CONCLUSIONS

With fewer predictors and higher discriminative power, the present nomogram may be a simple and reliable tool to identify patients with CKD at risk of CI-AKI, whereas further external validations are needed.

Retrospectively ECG-gated helical vs. non-ECG-synchronized high-pitch CTA of the aortic root for TAVI planning

Background

Multidetector computed tomography (MDCT) plays a key role in patient assessment prior to transcatheter aortic valve implantation (TAVI). However, to date no consensus has been established on what is the optimal pre-procedural imaging protocol. Variability in pre-TAVI acquisition protocols may lead to discrepancies in aortic annulus measurements and may potentially influence prosthesis size selection.

Purpose

The current study evaluates the magnitude of differences in aortic annulus measurements using max-systolic, end-diastolic, and non-ECG-synchronized imaging, as well as the impact of method on prosthesis size selection.

Material and methods

Fifty consecutive TAVI-candidates, who underwent retrospectively-ECG-gated CT angiography (CTA) of the aortic root, directly followed by non-ECG-synchronized high-pitch CT of the entire aorta, were retrospectively included. Aortic root dimensions were assessed at each 10% increment of the R-R interval (0–100%) and on the non-ECG-synchronized scan. Dimensional changes within the cardiac cycle were evaluated using a 1-way repeated ANOVA. Agreement in measurements between max-systole, end-diastole and non-ECG-synchronized scans was assessed with Bland-Altman analysis.

Results

Maximal dimensions of the aortic root structures and minimum annulus-coronary ostia distances were measured during systole. Max-systolic measurements were significantly and substantially larger than end-diastolic (p<0.001) and non-ECG-synchronized measurements (p<0.001). Due to these discrepancies, the three methods resulted in the same prosthesis size selection in only 48–62% of patients.

Conclusions

The systematic differences between max-systolic, end-diastolic and non-ECG-synchronized measurements for relevant aortic annular dimensions are both statistically significant and clinically relevant. Imaging strategy impacts prosthesis size selection in nearly half the TAVI-candidates. End-diastolic and non-ECG-synchronized imaging does not provide optimal information for prosthesis size selection. Systolic image acquisition is necessary for assessment of maximal annular dimensions and minimum annulus-coronary ostia distances.

A Practical Approach to Preventing Renal Complications in the Catheterization Laboratory

Contrast-induced acute kidney injury is a common complication in patients undergoing invasive procedures and is associated with increased mortality and morbidity. There is no effective approach to the management of this complication, and prevention remains of paramount importance. The 3 pillars of prevention are identification of high-risk patients, appropriate hydration before and after contrast exposure, eGFR-based contrast dosing and use of ultra-low contrast volume in high-risk patients. Most evidence supporting these practices is derived from patients undergoing coronary angiography or percutaneous coronary intervention but these basic principles can be applied to most patients undergoing contrast-based procedures in the catheterization laboratory.

Renal Dysfunction Following Elective Endovascular Aortic Aneurysm Repair

Abdominal aortic aneurysm (AAA) is a degenerative disease of the aortic wall with potentially fatal complications. Open repair (OR) was considered the gold standard, until the emergence of endovascular aneurysm repair (EVAR), which is less invasive and equally (if not more) effective. As the popularity of endovascular procedures grows, related complications become more evident, with kidney damage being one of them. Although acute kidney injury (AKI) following EVAR is relatively common, its true incidence is still uncertain. Also, there is insufficient data concerning long-term renal outcomes after EVAR, especially with repeated contrast agent exposure. Despite the lack of firm evidence on the effectiveness of individual strategies, it is evident that prevention of AKI following EVAR requires a multifactorial approach. This review focuses on recent findings based on human studies regarding the current evidence of renal impairment after EVAR, its quantification and strategies for its prevention.

Acute Renal Failure/Acute Kidney Injury (AKI) Associated with Endovascular Procedures

AKI is one of the most common yet underdiagnosed postoperative complications that can occur after any type of surgery. Contrast-induced nephropathy (CIN) is still poorly defined and due to a wide range of confounding individual variables, its risk is difficult to determine. CIN mainly affects patients with underlying chronic kidney disease, diabetes, sepsis, heart failure, acute coronary syndrome and cardiogenic shock. Further research is necessary to better understand pathophysiology of contrast-induced AKI and consequent implementation of effective prevention and therapeutic strategies. Although many therapies have been tested to avoid CIN, the only potent preventative strategy involves aggressive fluid administration and reduction of contrast volume. Regardless of surgical technique—open or endovascular—perioperative AKI is associated with significant morbidity, mortality and cost. Endovascular procedures always require administration of a contrast media, which may cause acute tubular necrosis or renal vascular embolization leading to renal ischemia and as a consequence, contribute to increased number of post-operative AKIs.

Renal Toxicity From Pemetrexed and Pembrolizumab in the Era of Combination Therapy in Patients With Metastatic Nonsquamous Cell NSCLC

The combination of chemotherapy and immune checkpoint inhibition (ICI) therapy is the current standard of care for most patients who are fit to undergo treatment for metastatic NSCLC. With this combination, renal toxicity was slightly higher than with chemotherapy alone in initial clinical trials. However, in recent real-world data, loss of kidney function is reported to be more frequent. Both chemotherapy and ICI therapy can induce renal impairment, although the mechanism of renal damage is different. Renal injury from chemotherapy is often ascribed to acute tubular injury and necrosis, whereas the main mechanism of injury caused by ICI therapy is acute tubulointerstitial nephritis. In cases of concomitant use of chemotherapy and ICI therapy, distinguishing the cause of renal failure is a challenge. Discriminating between these two causes is of utmost importance, as it would help assess which drug can be safely continued and which drug must be halted. This review aims to describe the underlying mechanisms of the renal adverse effects caused by chemotherapy and ICI therapy, leading to a suggested diagnostic and treatment algorithm on the basis of clinical, laboratory, radiographic, and pathologic parameters. This algorithm could serve as a supportive tool for clinicians to diagnose the underlying cause of acute kidney injury in patients treated with the combination of chemotherapy and immunotherapy.

Use of Contrast Medium Volume to Guide Prophylactic Hydration to Prevent Acute Kidney Injury After Contrast Administration: A Meta-Analysis

OBJECTIVE. The purpose of this study was to determine whether contrast medium volume and method of administration and baseline estimated glomerular filtration rate influence the efficacy of prophylactic hydration for prevention of acute kidney injury after contrast administration. MATERIALS AND METHODS. An online search of PubMed conducted on August 25, 2017, produced a total of 697 studies. After the reports were reviewed, nine were included in this study. The extracted data on all patients in these studies were separated into a group that received prophylactic hydration and a group that did not. The following three parameters were used for subgroup analysis: contrast medium volume, contrast administration method, and baseline estimated glomerular filtration rate. The t test was performed, and study-level odds ratios with 95% CIs and p values were calculated. Tests of heterogeneity were conducted. RESULTS. When the volume of contrast agent administered exceeded 100 mL, hydration was beneficial in the prevention of contrast-induced acute kidney injury (odds ratio, 0.546). If the volume was less than 100 mL, hydration had no efficacy in preventing contrast-induced acute kidney injury (odds ratio, 0.917). Administration route and baseline estimated glomerular filtration rate exerted no effect on the efficacy of prophylactic hydration. CONCLUSION. For patients who receive less than 100 mL of contrast medium, the prevalent practice for contrast-enhanced CT studies, prophylactic hydration may not be necessary, regardless of the estimated glomerular filtration rate or route of contrast administration. For patients undergoing procedures requiring administration of large volumes of contrast medium, however, hydration is recommended to prevent contrast-induced acute kidney injury.

Variation in contrast-associated acute kidney injury prophylaxis for percutaneous coronary intervention: insights from the Veterans Affairs Clinical Assessment, Reporting, and Tracking (CART) program

Background

Contrast-Associated Acute Kidney Injury (CA-AKI) is a serious complication associated with percutaneous coronary intervention (PCI). Patients with chronic kidney disease (CKD) have an elevated risk for developing this complication. Although CA-AKI prophylactic measures are available, the supporting literature is variable and inconsistent for periprocedural hydration and N-acetylcysteine (NAC), but is stronger for contrast minimization.

Methods

We assessed the prevalence and variability of CA-AKI prophylaxis among CKD patients undergoing PCI between October 2007 and September 2015 in any cardiac catheterization laboratory in the VA Healthcare System. Prophylaxis included periprocedural hydration with normal saline or sodium bicarbonate, NAC, and contrast minimization (contrast volume to glomerular filtration rate ratio ≤ 3). Multivariable hierarchical logistic regression models quantified site-specific prophylaxis variability. As secondary analyses, we also assessed CA-AKI prophylaxis measures in all PCI patients regardless of kidney function, periprocedural hydration in patients with comorbid CHF, and temporal trends in CA-AKI prophylaxis.

Results

From 2007 to 2015, 15,729 patients with CKD underwent PCI. 6928 (44.0%) received periprocedural hydration (practice-level median rate 45.3%, interquartile range (IQR) 35.5–56.7), 5107 (32.5%) received NAC (practice-level median rate 28.3%, IQR 22.8–36.9), and 4656 (36.0%) received contrast minimization (practice-level median rate 34.5, IQR 22.6–53.9). After adjustment for patient characteristics, there was significant site variability with a median odds ratio (MOR) of 1.80 (CI 1.56–2.08) for periprocedural hydration, 1.95 (CI 1.66–2.29) for periprocedural hydration or NAC, and 2.68 (CI 2.23–3.15) for contrast minimization. These trends were similar among all patients (with and without CKD) undergoing PCI. Among patients with comorbid CHF (n = 5893), 2629 (44.6%) received periprocedural hydration, and overall had less variability in hydration (MOR of 1.56 (CI 1.38–1.76)) compared to patients without comorbid CHF (1.89 (CI 1.65–2.18)). Temporal trend analysis showed a significant and clinically relevant decrease in NAC use (64.1% of cases in 2008 (N = 1059), 6.2% of cases in 2015 (N = 128, p = < 0.0001)) and no significant change in contrast-minimization (p = 0.3907).

Conclusions

Among patients with CKD undergoing PCI, there was low utilization and significant site-level variability for periprocedural hydration and NAC independent of patient-specific risk. This low utilization and high variability, however, was also present for contrast minimization, a well-established measure. These findings suggest that a standardized approach to CA-AKI prophylaxis, along with continued development of the evidence base, is needed.

Risk of acute kidney injury after contrast-enhanced computed tomography in emergency department

Background:

Despite its risks associated with renal injury, intravenous contrast media increases diagnostic efficacy and hence the chance of early diagnosis and treatment, which leaves clinicians in a dilemma regarding its use in emergency settings.

Objective:

The aim of this study was to determine the risk and predictors of contrast-induced acute kidney injury following intravenous contrast media administration for computed tomography in the emergency department.

Methods:

All patients aged 18 years and older who had a basal creatinine measurement within the last 8 h before contrast-enhanced computed tomography and a second creatinine measurement within 48–72 h after computed tomography scan between 1 January 2015 and 31 December 2017 were included in the study. Characteristics of patients with and without contrast-induced acute kidney injury development were compared. Multivariate regression analysis was used to assess the predictors for contrast-induced acute kidney injury.

Results:

A total of 631 patients were included in the final statistical analysis. After contrast media administration, contrast-induced acute kidney injury developed in 4.9% ( n = 31) of the patients. When the characteristics of patients are compared according to the development of contrast-induced acute kidney injury, significant differences were detected for age, initial creatinine, initial estimated glomerular filtration rate, and all acute illness severity indicators (hypotension, anemia, hypoalbuminemia, and need for intensive care unit admission). A multivariate logistic regression analysis was performed. The need for intensive care unit admission (odds ratio: 6.413 (95% confidence interval: 1.709–24.074)) and hypotension (odds ratio: 5.575 (95% confidence interval: 1.624–19.133)) were the main factors for contrast-induced acute kidney injury development.

Conclusion:

Our study results revealed that hypotension, need for intensive care, and advanced age were associated with acute kidney injury in patients receiving contrast media. Therefore, we believe that to perform contrast-enhanced computed tomography in emergency department should not be decided only by checking for renal function tests and that these predictors should be taken into consideration.

Random forest for prediction of contrast-induced nephropathy following coronary angiography

The majority of prediction models for contrast-induced nephropathy (CIN) have moderate performance. Therefore, we aimed to develop a better pre-procedural prediction tool for CIN following contemporary percutaneous coronary intervention (PCI) or coronary angiography (CAG). A total of 3469 patients undergoing PCI/CAG between January 2010 and December 2013 were randomly divided into a training (n = 2428, 70%) and validation data-sets (n = 1041, 30%). Random forest full models were developed using 40 pre-procedural variables, of which 13 variables were selected for a reduced CIN model. CIN developed in 78 (3.21%) and 37 of patients (3.54%) in the training and validation datasets, respectively. In the validation dataset, the full and reduced models demonstrated improved discrimination over classic Mehran, ACEF CIN risk scores (AUC 0.842 and 0.825 over 0.762 and 0.701, respectively, all P < 0.05) and common estimated glomerular filtration rate. Compared to that for the Mehran risk score model, the full and reduced models had significantly improved fit based on the net reclassification improvement (all P < 0.001) and integrated discrimination improvement (P = 0.001, 0.028, respectively). Using the above models, 2462 (66.7%), 661, and 346 patients were categorized into low (< 1%), moderate (1% to 7%), and high (> 7%) risk groups, respectively. Our pre-procedural CIN risk prediction algorithm (http://cincalc.com) demonstrated good discriminative ability and was well calibrated when validated. Two-thirds of the patients were at low CIN risk, probably needing less peri-procedural preventive strategy; however, the discriminative ability of CIN risk requires further external validation. TRIAL REGISTRATION: ClinicalTrials.gov NCT01400295.

Stanniocalcin-1 Alleviates Contrast-Induced Acute Kidney Injury by Regulating Mitochondrial Quality Control via the Nrf2 Pathway

Contrast-induced acute kidney injury (CI-AKI) is the third common cause of acute kidney injury (AKI), which is associated with poor short- and long-term outcomes. Currently, effective therapy strategy for CI-AKI remains lacking. Stanniocalcin-1 (STC1) is a conserved glycoprotein with antiapoptosis and anti-inflammatory functions, but the role of STC1 in controlling CI-AKI is unknown. Here, we demonstrated a protective role of STC1 in contrast-induced injury in cultured renal tubular epithelial cells and CI-AKI rat models. Recombinant human STC1 (rhSTC1) regulated mitochondrial quality control, thus suppressing contrast-induced mitochondrial damage, oxidative stress, inflammatory response, and apoptotic injury. Mechanistically, activation of the Nrf2 signaling pathway contributes critically to the renoprotective effect of STC1. Together, this study demonstrates a novel role of STC1 in preventing CI-AKI and reveals Nrf2 as a molecular target of STC1. Therefore, this study provides a promising preventive target for the treatment of CI-AKI.

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.

Effect of No Prehydration vs Sodium Bicarbonate Prehydration Prior to Contrast-Enhanced Computed Tomography in the Prevention of Postcontrast Acute Kidney Injury in Adults With Chronic Kidney Disease: The Kompas Randomized Clinical Trial

IMPORTANCE

Prevention of postcontrast acute kidney injury in patients with stage 3 chronic kidney disease (CKD) by means of prehydration has been standard care for years. However, evidence for the need for prehydration in this group is limited.

OBJECTIVE

To assess the renal safety of omitting prophylactic prehydration prior to iodine-based contrast media administration in patients with stage 3 CKD.

DESIGN, SETTING, AND PARTICIPANTS

The Kompas trial was a multicenter, noninferiority, randomized clinical trial conducted at 6 hospitals in the Netherlands in which 523 patients with stage 3 CKD were randomized in a 1:1 ratio to receive no prehydration or prehydration with 250 mL of 1.4% sodium bicarbonate administered in a 1-hour infusion before undergoing elective contrast-enhanced computed tomography from April 2013 through September 2016. Final follow-up was completed in September 2017. Data were analyzed from January 2018 to June 2019.

INTERVENTIONS

In total, 262 patients were allocated to the no prehydration group and 261 were allocated to receive prehydration. Analysis on the primary end point was available in 505 patients (96.6%).

MAIN OUTCOMES AND MEASURES

The primary end point was the mean relative increase in serum creatinine level 2 to 5 days after contrast administration compared with baseline (noninferiority margin of less than 10% increase in serum creatinine level). Secondary outcomes included the incidence of postcontrast acute kidney injury 2 to 5 days after contrast administration, mean relative increase in creatinine level 7 to 14 days after contrast administration, incidences of acute heart failure and renal failure requiring dialysis, and health care costs.

RESULTS

Of 554 patients randomized, 523 were included in the intention-to-treat analysis. The median (interquartile range) age was 74 (67-79) years; 336 (64.2%) were men and 187 (35.8%) were women. The mean (SD) relative increase in creatinine level 2 to 5 days after contrast administration compared with baseline was 3.0% (10.5) in the no prehydration group vs 3.5% (10.3) in the prehydration group (mean difference, 0.5; 95% CI, -1.3 to 2.3; P < .001 for noninferiority). Postcontrast acute kidney injury occurred in 11 patients (2.1%), including 7 of 262 (2.7%) in the no prehydration group and 4 of 261 (1.5%) in the prehydration group, which resulted in a relative risk of 1.7 (95% CI, 0.5-5.9; P = .36). None of the patients required dialysis or developed acute heart failure. Subgroup analyses showed no evidence of statistical interactions between treatment arms and predefined subgroups. Mean hydration costs were €119 (US $143.94) per patient in the prehydration group compared with €0 (US $0) in the no prehydration group (P < .001). Other health care costs were similar.

CONCLUSIONS AND RELEVANCE

Among patients with stage 3 CKD undergoing contrast-enhanced computed tomography, withholding prehydration did not compromise patient safety. The findings of this study support the option of not giving prehydration as a safe and cost-efficient measure.

TRIAL REGISTRATION

Netherlands Trial Register Identifier: NTR3764.

Use of Intravenous Iodinated Contrast Media in Patients with Kidney Disease: Consensus Statements from the American College of Radiology and the National Kidney Foundation

Intravenous iodinated contrast media are commonly used with CT to evaluate disease and to determine treatment response. The risk of acute kidney injury (AKI) developing in patients with reduced kidney function following exposure to intravenous iodinated contrast media has been overstated. This is due primarily to historic lack of control groups sufficient to separate contrast-induced AKI (CI-AKI; ie, AKI caused by contrast media administration) from contrast-associated AKI (CA-AKI; ie, AKI coincident to contrast media administration). Although the true risk of CI-AKI remains uncertain for patients with severe kidney disease, prophylaxis with intravenous normal saline is indicated for patients who have AKI or an estimated glomerular filtration rate less than 30 mL/min/1.73 m² who are not undergoing maintenance dialysis. In individual high-risk circumstances, prophylaxis may be considered in patients with an estimated glomerular filtration rate of 30-44 mL/min/1.73 m² at the discretion of the ordering clinician. This article is a simultaneous joint publication in Radiology and Kidney Medicine. The articles are identical except for stylistic changes in keeping with each journal's style. Either version may be used in citing this article.

Acute kidney injury from contrast-enhanced CT procedures in patients with cancer: white paper to highlight its clinical relevance and discuss applicable preventive strategies

Patients with cancer are subjected to several imaging examinations which frequently require the administration of contrast medium (CM). However, it has been estimated that acute kidney injury (AKI) due to the injection of iodinated CM accounts for 11% of all cases of AKI, and it is reported in up to 2% of all CT examinations. Remarkably, the risks of developing AKI are increased in the elderly, in patients with chronic kidney disease or diabetes, and with dehydration or administration of nephrotoxic chemotherapeutics. Given the common occurrence of postcontrast acute kidney injury (PC-AKI) in clinical practice, primary care physicians and all specialists involved in managing patients with cancer should be aware of the strategies to reduce the risk of this event. In 2018, a panel of four experts from the specialties of radiology, oncology and nephrology were speakers at the annual meeting of the Italian Society of Medical Radiology (Società Italiana di Radiologia Medica e Interventistica), with the aim of commenting on existing evidence and providing their experience on the incidence and management of PC-AKI in patients with cancer. The discussion represented the basis for this white paper, which is intended to be a practical guide organised by statements describing methods to reduce renal injury risks related to CM-enhanced CT examinations in patients with cancer.

Efficacy and Safety of a Balanced Salt Solution Versus a 0.9% Saline Infusion for the Prevention of Contrast-Induced Acute Kidney Injury After Contrast-Enhanced Computed Tomography

Rationale & Objective

We aimed to elucidate whether a balanced salt solution decreases the occurrence of contrast-induced acute kidney injury (CI-AKI) after contrast-enhanced computed tomography (CE-CT) as compared to 0.9% saline solution.

Study Design

A randomized clinical trial.

Setting & Participants

The study was performed in 14 tertiary hospitals in South Korea. Patients with estimated glomerular filtration rates (eGFRs) < 45 or <60 mL/min/1.73 m² and additional risk factors (age ≥ 60 years or diabetes) who were undergoing scheduled CE-CT were included from December 2016 to December 2018.

Intervention

An open-label intervention was performed. The study group received a balanced salt solution and the control group received 0.9% saline solution as prophylactic fluids for CE-CT.

Outcomes

The primary outcome was CI-AKI, defined by creatinine level elevation ≥ 0.5 mg/dL or 25% from baseline within 48 to 72 hours after CE-CT. Secondary outcomes included AKI defined based on the KDIGO (Kidney Disease: Improving Global Outcomes) guideline, eGFR changes, death, or requiring dialysis within 6 months after CE-CT.

Results

493 patients received the study fluids. The control and study groups included 251 and 242 patients, respectively. The occurrence of CI-AKI in the study (10 [4.2%]) and control (17 [6.8%]) groups was not significantly different (P = 0.27). No significant difference was present for the secondary outcomes; AKI by the KDIGO definition (study: 19 [7.9%], control: 27 [10.8%]; P = 0.33), death/dialysis (study: 11 [4.7%], control: 9 [3.7%]; P = 0.74), and eGFR changes (study: 0.1 ± 0.2 mg/dL, control: 0.3 ± 2.8 mg/dL; P = 0.69).

Limitations

This study failed to meet target enrollment.

Conclusions

The risk for CI-AKI was similar after administration of a balanced salt solution and after use of 0.9% saline solution during CE-CT in higher-risk patients.

Funding

This study was funded by CJ Healthcare (CS2015_0046).

Trial Registration

Registered at ClinicalTrials.gov with study number NCT02799368.

Impact on clinical practice of updated guidelines on iodinated contrast material: CINART

Objective

Guidelines on safe use of iodinated contrast material recommend intravenous prophylactic hydration to prevent post-contrast adverse (renal) effects. Recently, guidelines have been updated and standard prophylaxis is no longer recommended for the majority of patients. The current study aims to evaluate the consequences for clinical practice of the updated guidelines in terms of complications, hospitalisations, and costs.

Methods

The Contrast-Induced Nephropathy After Reduction of the prophylaxis Threshold (CINART) project is a retrospective observational study. All elective procedures with intravascular iodinated contrast administration at Maastricht University Medical Centre (UMC+) in patients aged > 18 years, formerly eligible for prophylaxis (eGFR 30–44 ml/min/1.73 m² or eGFR 45–59 ml/min/1.73 m² in combination with diabetes or > 1 predefined risk factor), and currently eligible for prophylaxis (eGFR < 30 ml/min/1.73 m²) were included. Data were used to calculate relative reductions in complications, hospitalisations, and costs associated with standard prophylactic intravenous hydration. CINART is registered with Clinicaltrials.gov: NCT03227835.

Results

Between July 1, 2017, and July 1, 2018, 1992 elective procedures with intravascular iodinated contrast in patients formerly and currently eligible for prophylaxis were identified: 1808 in patients formerly eligible for prophylaxis and 184 in patients currently eligible for prophylaxis. At Maastricht UMC+, guideline updates led to large relative reductions in numbers of complications of prophylaxis (e.g. symptomatic heart failure; − 89%), extra hospitalisations (− 93%), and costs (− 91%).

Conclusion

Guideline updates have had a demonstrable impact on daily clinical practice benefiting patient, hospital, and health care budgets. Clinical practice varies between institutions and countries; therefore, a local estimation model is provided with which local impact on costs, hospitalisations, and complications can be calculated.

Key Points

• Clinical practice guidelines recommend prophylactic intravenous hydration to prevent post-contrast adverse outcomes such as contrast-induced acute kidney injury.

• Clinical practice guidelines have recently been updated, and standard prophylaxis is no longer recommended for the majority of patients.

• The guideline updates have a large impact on daily clinical practice: relative reductions at Maastricht UMC+ were − 89% prophylaxis complications, − 93% hospitalisations, and − 91% costs, and similar reductions are expected for Dutch and adherent European medical centres.

Electronic supplementary material

The online version of this article (10.1007/s00330-020-06719-7) contains supplementary material, which is available to authorized users.

Carbon dioxide-angiography for patients with peripheral arterial disease at risk of contrast-induced nephropathy

Patients with peripheral arterial disease (PAD) and critical limb ischemia are at risk for limb amputation and require urgent management to restore blood flow. Patients with PAD often have several comorbidities, including chronic kidney disease, diabetes mellitus, and hypertension. Diagnostic and interventional angiography using iodinated contrast agents provides excellent image resolution but can be associated with contrast-induced nephropathy (CIN). The use of carbon dioxide (CO₂) as a contrast agent reduces the volume of iodine contrast required for angiography and reduces the incidence of CIN. However, CO₂ angiography has been underutilized due to concerns regarding safety and image quality. Modern CO₂ delivery systems with advanced digital subtraction angiography techniques and hybrid angiography have improved imaging accuracy and reduced the incidence of CIN. Awareness of the need for optimal imaging conditions, contraindications, and potential complications have improved the safety of CO₂ angiography. This review aims to highlight current technological advances in the delivery of CO₂ in vascular angiography for patients with PAD and critical limb ischemia, which result in limb preservation while preventing kidney damage.

Role of serum cystatin C in the prediction of contrast-induced nephropathy after intra-arterial interventions

Background

The diagnosis of contrast-induced nephropathy (CIN) is usually based on changes in serum creatinine (sCr). However, sCr has poor sensitivity as a biomarker of kidney injury. The aim of this study was to investigate the usefulness of serum cystatin C (sCysC) to predict CIN after intra-arterial interventions.

Methods

A total of 360 consecutive patients underwent intra-arterial procedures using digital subtraction angiography. SCr, sCysC, and estimated glomerular filtration rate were measured at 1 to 2 days before and at 48, 72 h, and 7 days after the procedure.

Results

Thirty-one patients (8.61%) developed CIN. Receiver operating characteristic (ROC) curve analysis showed that pre-operative sCysC levels had good discriminatory power (area under the curve [AUC] = 0.634; 95% confidence interval [CI] = 0.526–0.743) for evaluating the risk of CIN after an endovascular procedure, with a sensitivity of 53.33% and specificity of 73.70%. ROC analysis showed that sCysC at 48 h after contrast medium administration was predictive of CIN after an endovascular procedure (AUC = 0.735; 95% CI = 0.647–0.822) with satisfactory sensitivity of 74.20% and specificity of 63.90%. Diabetes mellitus was an independent risk factor for CIN (odds ratio = 2.778; 95% CI = 1.045–7.382; P = 0.040).

Conclusions

SCysC is an appropriate biomarker to predict the occurrence of CIN. Baseline sCysC before an intervention is useful to obtain a preliminary estimate of the risk of CIN. A 48-h cut-off value of sCysC of 0.99 mg/L after an endovascular procedure may help to rule out patients at lower risk of CIN.

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.