Prophylactic Intravenous Hydration to Protect Renal Function From Intravascular Iodinated Contrast Material (AMACING): Long-term Results of a Prospective, Randomised, Controlled Trial

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.

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

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

Renalism: Avoiding Procedure, More Harm than Good?

Management of patients with chronic kidney disease (CKD) is complex in terms of their disease pathophysiology. Cardiovascular disease is one of the leading causes of death in individuals with CKD. These patients are very prone for developing increase in creatinine usually enough to meet criteria for acute kidney injury spontaneously and after mild insults. The fear of precipitating an acute kidney injury or worsening of CKD (ie, renalism) is preventing current day physicians in providing clinically indicated interventions that have a positive impact on their morbidity and mortality.

Optimization of Preprocedural Full-cycle Computed Tomography in Patients Referred for Transcatheter Tricuspid Valve Repair: Test Bolus Versus Bolus Tracking

PURPOSE/OBJECTIVES

Advancements in transcatheter mitral and tricuspid valve repair have resulted in growing demands in preprocedural computed tomography (CT) imaging. Due to the introduction of multidetector CT (MDCT), shorter acquisition times as well as high rates of heart failure and arrhythmias in this specific patient population, optimal synchronization between the passage of contrast agent and data acquisition is mandatory. There is no consensus on which acquisition technique should be used in this patient population. We aimed to optimize our preprocedural CT protocol comparing bolus tracking (BT) and test bolus (TB) techniques.

MATERIALS AND METHODS

We performed a retrospective analysis on 151 patients referred for full-cycle MDCT evaluation for transcatheter tricuspid valve repair comparing BT with TB (BT n=75 TB n=75). Contrast-to-noise ratios (CNR) were obtained. Demographic data, laboratory, electrocardiographic, and transthoracic echocardiography/transoesophageal echocardiography parameters were collected from electronic health records. Also, the volume of contrast agent and saline chaser and radiation dose length product and milliampere seconds were collected.

RESULTS

BT and TB resulted in comparable CNR (BT: 0.47 [0.34 to 0.98]; TB: 0.51 [0.41 to 1.40]; P =0.1). BT was associated with a shorter scan duration (BT: 8.3 min [4.1 to 24.4]; TB: 13.9 min [6.2 to 41.4]; P <0.001), less radiation in terms of dose length product (BT: 1186±585; TB: 1383±679, P =0.04), and lower total volume administration (BT: 101 mL [63 to 16]; TB: 114 mL [71 to 154]; P <0.001). In patients with severely impaired ejection fraction (left ventricular ejection fraction [LVEF] ≤35%; n=65 [TB n=31; BT n=34]) using the TB technique yielded significantly better image quality in terms of CNR (TB=0.57 [0.41 to 1.07); BT=0.41 [0.34 to 0.65]; P =0.02).

CONCLUSION

In patients with impaired LVEF (LVEF≤35%), the TB technique yielded significantly superior image quality and may be the preferred approach in this specific patient population. BT showed advantages in terms of shorter duration, less radiation, and lower contrast agent volume.

Atherosclerotic plaque composition and specific endovascular considerations in the end stage renal disease patients: a narrative review

Background and Objective

Vascular calcification (VC) and resulting vascular disease is one of the major causes of cardiovascular morbidity and mortality in patients with chronic kidney disease (CKD). CKD itself is increasingly recognized as a risk factor for cardiac and peripheral arterial disease (PAD). This paper examines the atherosclerotic plaque composition and specific endovascular considerations in the end stage renal disease (ESRD) patients. The literature was reviewed regarding the current status of medical and interventional management arteriosclerotic disease in patients with CKD. Lastly, three representative cases displaying typical endovascular treatment options are provided.

Methods

A literature search was performed in PubMed covering publications up to September 2021 as well as discussion with experts in the field.

Key Content and Findings

The high prevalence of atherosclerotic lesions in patients with chronic renal failure and high (re-)stenosis cause problems in the medium and long term as vascular calcium load represents one of the most widely encountered predictors of failure of endovascular treatment of PAD and future cardiovascular events (e.g., coronary calcium score). Patients with CKD also suffer from a greater risk for major vascular adverse events in general and worse revascularization outcomes following peripheral vascular intervention. A correlation between calcium burden and drug-coated balloon (DCB) performance has been established for PAD necessitating the need for different tools to cope with vascular calcium such as endoprosthesis or braided stents. Patients with CKD are at a higher risk of developing contrast-induced nephropathy (CIN). In addition to recommendations such as the administration of intravenous fluids, carbon dioxide (CO₂) angiography is one option to potentially provide an effective and safe alternative both to iodine-based contrast media allergy and to the use of iodine-based contrast media in patients with CKD.

Conclusions

Management and endovascular procedures of patients with ESRD are complex. In the course of time, new endovascular therapy methods have been developed such as directional atherectomy (DA) and the so-called "pave-and-crack" technique to deal with high vascular calcium burden. Besides interventional therapy, vascular patients with CKD benefit from aggressive medical management.

Long-term safety of withholding standard prophylaxis in patients with moderate chronic kidney disease

In the latest ESUR contrast media guidelines, standard prophylaxis is no longer recommended for patients with moderate chronic kidney disease (CKD). In the absence of solid evidence, guideline updates are often based on indirect evidence and expert opinion. Likewise, evidence supporting the withdrawal of standard prophylaxis in moderate CKD patients was scarce and mostly indirect, but did include one randomised controlled trial evaluating guideline-recommended standard prophylactic intravenous hydration against a group receiving no prophylaxis (A MAastricht Contrast-Induced Nephropathy Guideline (AMACING) trial). Since then, benefits of the updated guideline recommendation for patient and hospital burden have been numerated and were shown to be substantial. The current special report provides data on long-term safety from the AMACING randomised controlled trial. KEY POINTS: • In the latest version of ESUR clinical practice guidelines for safe use of contrast media, standard prophylaxis is no longer recommended for patients with moderate chronic kidney disease. • Benefits of this change in recommendations for patient and hospital burden have been numerated. The current report provides data on long-term safety from the AMACING randomised controlled trial. • No disadvantage of withholding prophylaxis could be discerned. Results suggest that, in this population, underlying disease is more relevant for survival and prognosis than contrast administration itself.

The Incidence and Associated Risk Factors of Contrast-Induced Nephropathy after Contrast-Enhanced Computed Tomography in the Emergency Setting: A Systematic Review

Iodinated contrast media (ICM) during contrast-enhanced computed tomography (CECT) in the emergency department (ED) is essential to diagnose acute conditions, despite risks of contrast-induced nephropathy (CIN) development and its associated complications. This systematic review aims to evaluate the incidence of CIN and CIN-induced complications, and to explore the relevance of classical risk factors for CIN among ED patients receiving ICM. PubMed, Cochrane, and Web of Science were used on 30 August 2021 to search for peer-reviewed English articles reporting on CIN incidence among ED patients aged ≥18 years who underwent an intravenous CECT. The inclusion criteria included studies that were in English, peer-reviewed, and involved ED patients aged ≥18 years who underwent single intravenous CECT. Studies on intra-arterial procedures and preventive strategies, meta-analyses, clinical guidelines, review articles, and case reports were excluded. The JBI critical appraisal checklist was applied to assess the risk of bias. In total, 18 studies were included wherein 15 were retrospective studies while three were prospective studies. We found a relatively higher CIN incidence in the ED, with variations owing to the CIN definitions. Several classical risk factors including acute hypotension remain linked to CIN onset in ED settings unlike factors such as age and diabetes. While risk of adverse renal events due to CIN is low, there is higher risk of CIN-induced mortality in the ED. Therefore, with the higher incidence of CIN and CIN-induced mortality rates in the ED, ICM administration during CECT in the ED should still be clinically justified after assessing both benefits and risks.

Contrast-induced nephropathy in non-cardiac vascular procedures, a narrative review: Part 2

This is Part 2 of a narrative review summarizing the literature on CIN after non-cardiac vascular diagnostic or therapeutic procedures, focusing on peripheral artery disease (PAD) and renal artery stenosis (RAS). Part 1 discussed CIN in relation to aortic aneurysms and carotid stenosis. We comment on the incidence, biomarkers, risk factors, and consequences of CIN in patients with PAD or RAS, as well as on strategies to prevent CIN. Future perspectives in the field of CIN in relation to non-cardiac vascular procedures are also considered.

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.

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.

Updates in Vascular Computed Tomography

Computed tomography angiography (CTA) has become a mainstay for the imaging of vascular diseases, because of high accuracy, availability, and rapid turnaround time. High-quality CTA images can now be routinely obtained with high isotropic spatial resolution and temporal resolution. Advances in CTA have focused on improving the image quality, increasing the acquisition speed, eliminating artifacts, and reducing the doses of radiation and iodinated contrast media. Dual-energy computed tomography provides material composition capabilities that can be used for characterizing lesions, optimizing contrast, decreasing artifact, and reducing radiation dose. Deep learning techniques can be used for classification, segmentation, quantification, and image enhancement.

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.