Contrast-induced nephropathy

Comparison of micro-flow imaging and contrast-enhanced ultrasonography in assessing segmental congestion after right living donor liver transplantation

PURPOSE

This study aimed to determine whether micro-flow imaging (MFI) offers diagnostic performance comparable to that of contrast-enhanced ultrasonography (CEUS) in detecting segmental congestion among patients undergoing living donor liver transplantation (LDLT).

METHODS

Data from 63 patients who underwent LDLT between May and December 2022 were retrospectively analyzed. MFI and CEUS data collected on the first postoperative day were quantified. Segmental congestion was assessed based on imaging findings and laboratory data, including liver enzymes and total bilirubin levels. The reference standard was a postoperative contrast-enhanced computed tomography scan performed within 2 weeks of surgery. Additionally, a subgroup analysis examined patients who underwent reconstruction of the middle hepatic vein territory.

RESULTS

The sensitivity and specificity of MFI were 73.9% and 67.5%, respectively. In comparison, CEUS demonstrated a sensitivity of 78.3% and a specificity of 75.0%. These findings suggest comparable diagnostic performance, with no significant differences in sensitivity (P=0.655) or specificity (P=0.257) between the two modalities. Additionally, early postoperative laboratory values did not show significant differences between patients with and without congestion. The subgroup analysis also indicated similar diagnostic performance between MFI and CEUS.

CONCLUSION

MFI without contrast enhancement yielded results comparable to those of CEUS in detecting segmental congestion after LDLT. Therefore, MFI may be considered a viable alternative to CEUS.

Current updates in radiocontrast-associated acute kidney injury

Contrast-associated acute kidney injury (CA-AKI) is an abrupt decline in kidney function occurring after a recent exposure to iodinated radiocontrast media. CA-AKI presents as elevated serum creatinine level or decreased urine output. CA-AKI is the third leading cause of inpatient AKI. The incidence of CA-AKI varies according to patient population characteristics, ranging from 5% in the general population to as high as 30% in special populations with preexisting comorbidities such as diabetes mellitus, cardiovascular disease, and chronic kidney disease. The development of CA-AKI places a heavy toll on patients and the healthcare system secondary to increased patient morbidity, mortality, hospital length of stay, readmission risk, and healthcare cost. Patients undergoing cardiac catheterization are of special interest, since they have higher risk of developing CA-AKI and its associated complications. The recognition, prevention, and management of CA-AKI has improved over the past few years with the introduction of fluid management guidelines, using less nephrotoxic radiocontrast media, and preprocedural CA-AKI risk assessment. Future advancements in patients' CA-AKI risk stratification and early detection will facilitate prompt initiation of mitigation treatment plans and decrease associated complications.

Is eGFR ≥60 mL/min/1.73 m2 in Patients Undergoing Coronary Angiography Really Safe for Contrast Nephropathy?

The aim of the present study was to define the risk factors associated with contrast-induced acute kidney injury (CI-AKI) in patients who underwent coronary artery angiography (CAG). In this retrospective cohort study, patients who underwent CAG between March 2014 and January 2022 were evaluated. A total of 2923 eligible patients were included in the study. Univariate and multivariate logistic regression analysis was used to identify the predictive factors. CI-AKI developed in 77 (2.6%) of 2923 patients. In multivariate analysis, diabetes mellitus (DM), chronic kidney disease (CKD), and estimated glomerular filtration rate (eGFR) were found to be independent factors associated with CI-AKI. In the subgroup analysis of patients with eGFR ≥60 mL/min/1.73 m2, eGFR remained a predictor of CI-AKI (Odds ratio (OR): .89, 95% CI: .84-.93; that is, a lower eGFR remains a risk factor for CI-AKI). In the receiving operating characteristic (ROC) analysis of patients with eGFR ≥60 mL/min/1.73 m2, the area under the curve of the eGFR was .826. Using the ROC curve based on Youden's index, the eGFR cut-off was found to be 70 mL/min/1.73 m2 for patients with eGFR ≥60 mL/min/1.73 m2. eGFR is also an important risk factor in patients with eGFR 60-70 mL/min/1.73 m2.

Utility of abbreviated MRI in the post-treatment evaluation of rectal cancer

BACKGROUND

Post-treatment evaluation of patients with rectal cancer (RC) using magnetic resonance imaging (MRI) burdens medical resources, necessitating an exploration of abbreviated protocols.

PURPOSE

To evaluate the diagnostic performance of abbreviated MRI (A-MRI) for the post-treatment evaluation of RC patients.

MATERIAL AND METHODS

This retrospective study included RC patients who underwent non-contrast rectal MRI and standard liver MRI, as well as abdominal contrast-enhanced computed tomography (CECT) for post-treatment evaluation. A-MRI comprised diffusion-weighted imaging (DWI) and T2-weighted imaging of the upper abdomen and the pelvic cavity. Three radiologists independently reviewed A-MRI, CECT, and standard liver MRI in the detection of viable disease. The diagnostic performances were compared using a reference standard considering all available information, including pathology, FDG-PET, endoscopic results, and clinical follow-up.

RESULTS

We included 78 patients (50 men, 28 women; mean age=60.9 ± 10.2 years) and observed viable disease in 34 (43.6%). On a per-patient-basis analysis, A-MRI showed significantly higher sensitivity (95% vs. 81%, P = 0.04) and higher accuracy (93% vs. 82%, P < 0.01), compared to those of CECT, while A-MRI showed comparable sensitivity (91% vs. 91%, P = 0.42) and accuracy (97% vs. 98%, P = 0.06) to that of standard liver MRI. On a per-lesion-based analysis, A-MRI exhibited significantly superior lesion detectability than that of CECT (figure of merit 0.91 vs. 0.77, P < 0.01) and comparable to that of standard liver MRI (figure of merit 0.91 vs. 0.92, P = 0.75).

CONCLUSION

A-MRI exhibited higher sensitivity and diagnostic accuracy than those of CECT in the post-treatment evaluation of RC, while it showed comparable performances with standard liver MRI. A-MRI provides diagnostic added value in the follow-up of RC patients.

Evaluation of Emerging Predictors for Contrast-Induced Nephropathy in High-Risk Patients Undergoing Percutaneous Coronary Intervention

OBJECTIVE

The objective of this study is to investigate the occurrence and factors that influence the development of contrast-induced nephropathy (CIN) in high-risk patients undergoing angioplasty and to evaluate the effectiveness of the Mehran risk score in predicting CIN among this patient population.

MATERIALS AND METHOD

This prospective, observational study enrolled patients undergoing elective coronary angiography or a percutaneous coronary intervention (PCI) procedure. The patients were stratified into four risk groups based on the Mehran risk score, a validated tool for predicting the risk of CIN. Univariate and multivariate analyses were conducted to evaluate the risk factors associated with the development of CIN. A p-value of <0.05 was considered to indicate statistical significance.

RESULTS

During the study period, a total of 55 high-risk patients underwent PCI. The incidence of CIN was 25.5% (n=14). Univariate and multivariate analyses revealed that age >75 years and estimated glomerular filtration rate (eGFR) <60 (p<0.05) were independently associated with a significantly increased risk of developing CIN. A considerable proportion of patients (23; 41.8%) in the study were categorized as having an intermediate risk for CIN based on the Mehran risk score.

CONCLUSION

This study observed a high incidence of CIN and encourages the use of predictive tools like the Mehran risk score to assess the risk of CIN occurrence, with age over 70 years and eGFR less than 60 emerging as significant.

Effect of patient characteristics on aortic attenuation in iodinated contrast-enhanced Abdominopelvic CT: A retrospective study

INTRODUCTION

Contrast Enhanced Computed Tomography (CECT) abdomen and pelvis is a common imaging procedure. Hospitals typically follow fixed protocols of contrast volume administration for triple-phase CECT abdomen and pelvis scans and have found that patients are either underdosed or overdosed with respect to their body habitus. The aim of the study was to correlate different patient characteristics such as Total body weight (TBW), Lean Body Mass (LBM), Body Mass Index (BMI), Body Surface Area (BSA) and Blood Volume (BV) with aortic enhancement in the arterial and portal venous phases for CECT Abdomen and pelvis.

METHODS

A total of 106 patients who underwent triple-phase CECT abdomen & pelvis were retrospectively studied. A circular region-of-interest (ROI) of 100 mm2 was positioned on descending aorta for unenhanced, arterial, and portal venous phases to measure the aortic enhancement in Hounsfield's units. Measure of contrast attenuation (ΔH) was calculated from the difference of CT values on unenhanced images and contrast images. Correlation analysis was performed to evaluate the relation of patient body characteristics with aortic enhancement.

RESULTS

Correlation analysis revealed that BMI exhibited the least correlation when compared to the other characteristics in both arterial (r = -0.3; p = 0.002) and portovenous phases (r = -0.35; p < 0.001) whereas TBW, LBW, BSA and BV reported moderate inverse correlations. BV was found to be the strongest of all characteristics under linear regression.

CONCLUSION

The study supports the use of protocols that adjust contrast volume to either TBW, LBW, BSA, or BV for CT abdomen and pelvis scan.

IMPLICATION OF PRACTICE

The right body parameter ensures optimal contrast enhancement, improving the visualization of anatomical structures and helps in adapting tailored contrast injection protocols.

First Experience With Augmented Reality Guidance for Cerebral Embolic Protection During TAVR

Background

Augmented reality (AR) guidance holds potential to improve transcatheter interventions by enabling visualization of and interaction with patient-specific 3-dimensional virtual content. Positioning of cerebral embolic protection devices (CEP) during transcatheter aortic valve replacement (TAVR) increases patient exposure to radiation and iodinated contrast, and increases procedure time. AR may enhance procedural guidance and facilitate a safer intervention.

Objectives

The purpose of this study was to develop and test a novel AR guidance system with a custom user interface that displays virtual, patient-specific 3-dimensional anatomic models, and assess its intraprocedural impact during CEP placement in TAVR.

Methods

Patients undergoing CEP during TAVR were prospectively enrolled and assigned to either AR guidance or control groups. Primary endpoints were contrast volume used prior to filter placement, times to filter placement, and fluoroscopy time. Postprocedure questionnaires were administered to assess intraprocedural physician experience with AR guidance.

Results

A total of 24 patients presenting for TAVR were enrolled in the study (12 with AR guidance and 12 controls). AR guidance eliminated the need for aortic arch angiograms prior to device placement thus reducing contrast volume (0 mL vs 15 mL, P < 0.0001). There was no significant difference in the time required for filter placement or fluoroscopy time. Postprocedure questionnaires indicated that AR guidance increased confidence in wiring of the aortic arch and facilitated easier device placement.

Conclusions

We developed a novel AR guidance system that eliminated the need for additional intraprocedural angiograms prior to device placement without any significant difference in time to intervention and offered a subjective improvement in performance of the intervention.

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.

Pulmonary embolism diagnostic strategies in patients with COPD exacerbation: Post-hoc analysis of the PEP trial

BACKGROUND

The prevalence of pulmonary embolism (PE) is approximately 11-17 % in patients with an acute exacerbation of chronic obstructive pulmonary disease (AE-COPD). The optimal diagnostic strategy for PE in these patients remains undetermined.

AIMS

To evaluate the safety and efficacy of standard (revised Geneva and Wells PE scores combined with fixed D-dimer cut-off) and computed tomography pulmonary angiogram (CTPA)-sparing diagnostic strategies (ADJUST-PE, YEARS, PEGeD, 4PEPS) in patients with AE-COPD.

METHOD

Post-hoc analyses of data from the multicenter prospective PEP study were performed. The primary outcome was the diagnostic failure rate of venous thromboembolism (VTE) during the entire study period. Secondary outcomes included diagnostic failure rate of PE and deep venous thrombosis (DVT), respectively, during the entire study period and the number of CTPA needed per diagnostic strategy.

RESULTS

740 patients were included. The revised Geneva and Wells PE scores combined with fixed D-dimer cut-off had a diagnostic failure rate of VTE of 0.7 % (95%CI 0.3 %-1.7 %), but >70.0 % of the patients needed imaging. All CTPA-sparing diagnostic algorithms reduced the need for CTPAs (-10.1 % to -32.4 %, depending on the algorithm), at the cost of an increased VTE diagnosis failure rate of up to 2.1 % (95%CI 1.2 %-3.4 %).

CONCLUSION

Revised Geneva and Wells PE scores combined with fixed D-dimer cut-off were safe, but a high number of CTPA remained needed. CTPA-sparing algorithms would reduce imaging, at the cost of an increased VTE diagnosis failure rate that exceeds the safety threshold. Further studies are needed to improve diagnostic management in this population.

Fusion imaging for pulmonary artery embolization: impact on fluoroscopy duration and contrast agent exposure

OBJECTIVES

To assess the impact of fusion imaging guidance on fluoroscopy duration and volume of contrast agent used for pulmonary artery embolization.

METHODS

Thirty-four consecutive patients who underwent pulmonary artery embolization for pulmonary arterio-venous malformation (n = 28) or hemoptysis (n = 6) were retrospectively included. In the experimental group (n = 15), patients were treated using fusion imaging with 2D/3D registration. In the control group (n = 19), no fusion imaging has been used. Fluoroscopy duration and amount of contrast used were measured and intergroup comparison was performed.

RESULTS

The average volume of contrast agent used for embolization in the fusion group (118.3 ml) was significantly lower than in the control group (285.3 ml) (p < 0.002). The mean fluoroscopy duration was not significantly different between both groups (19.5 min in the fusion group vs 31.4 min in the control group (p = 0.10)). No significant difference was observed regarding the average X-ray exposure (Air Kerma) (p = 0.68 in the univariate analysis). Technical success rate was 100% for both groups.

CONCLUSION

Fusion imaging significantly reduces contrast medium volumes needed to perform pulmonary artery embolization. The fluoroscopy duration and the X-ray exposure did not vary significantly.

ADVANCES IN KNOWLEDGE

CTA-based fusion imaging using 2D-3D registration is a valuable tool for performing pulmonary artery embolization, helpful for planning and guiding catheterization.Compared to the traditional imaging guidance, fusion imaging reduces the volume of contrast agent used.

The association between hemogram parameters and the development of contrast-induced nephropathy in patients presenting with non-ST-elevation myocardial infarction

Objectives

Hemogram parameters such as mean platelet volume (MPV), neutrophil/lymphocyte ratio (NLr), red cell distribution width and platelet distribution width are widely used inflammatory indicators to assess prognosis in various cardiovascular diseases. In this study, we aimed to investigate the role of hemogram parameters to predict the development of contrast-induced nephropathy (CIN) in patients presenting with non-ST segment elevation myocardial infarction (non-STEMI) and treated with percutaneous coronary intervention (PCI).

Methods

All pateints who underwent PCI with a diagnosis of non-STEMI between 2017 and 2020 in our center were included retrospectively in this study.

Results

A total of 387 patients were included in this retrospective study. Advanced age (p=0.001, β:0.005, OR [95 % CI]: 0.002-0.007), diabetes mellitus (p=0.013, β:0.205, OR [95 % CI]: 0.150-0.260), congestive heart failure (p=0.009, β:0.095, OR [95 % CI]: 0.024-0.166), volume of contrast medium (p=0.008, β:0.241, OR [95 % CI]: 0.184-0.392), MPV (p=0.02, β:0.047, OR [95 % CI]: 0.028-0.065) and NLr (p=0.001, β:0.052, OR [95 % CI]: 0.040-0.063) were found as independent risk factors associated with CIN development according to multivariate logistic regression analysis. A cut off value of 5.5 for NLr was associated with 79.6 % sensitivity and 79.5 % specificity and 9.05 for MPV was associated with 64.1 % sensitivity and 58.7 % specificity in prediction of CIN development.

Conclusions

Hematological parameters, assessed by routine blood count analysis may serve as a promising and useful marker for CIN especially when used in combination with traditional risk factors. MPV and NLr were demonstrated as predictors of CIN development in non-STEMI patients who were treated with PCI in our study.

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.

Optimal Abdominal CT Image Quality in Non-Lean Patients: Customization of CM Injection Protocols and Low-Energy Acquisitions

We compared the image quality of abdominopelvic single-energy CT with 100 kVp (SECT-100 kVp) and dual-energy CT with 65 keV (DECT-65 keV) obtained with customized injection protocols to standard abdominopelvic CT scans (SECT-120 kVp) with fixed volumes of contrast media (CM). We retrospectively included 91 patients (mean age, 60.7 ± 15.8 years) with SECT-100 kVp and 83 (mean age, 60.3 ± 11.7 years) patients with DECT-65 keV in portovenous phase. Total body weight-based customized injection protocols were generated by a software using the following formula: patient weight (kg) × 0.40/contrast concentration (mgI/mL) × 1000. Patients had a prior abdominopelvic SECT-120 kVp with fixed injection. Iopamidol-370 was administered for all examinations. Quantitative and qualitative image quality comparisons were made between customized and fixed injection protocols. Compared to SECT-120 kVp, customized injection yielded a significant reduction in CM volume (mean difference = 9-12 mL; p ≤ 0.001) and injection rate (mean differences = 0.2-0.4 mL/s; p ≤ 0.001) in all weight categories. Improvements in attenuation, noise, signal-to-noise and contrast-to-noise ratios were observed for both SECT-100 kVp and DECT-65 keV compared to SECT-120 kVp in all weight categories (e.g., pancreas DECT-65 keV, 1.2-attenuation-fold increase vs. SECT-120 kVp; p < 0.001). Qualitative scores were ≥4 in 172 cases (98.8.4%) with customized injections and in all cases with fixed injections (100%). These findings suggest that customized CM injection protocols may substantially reduce iodine dose while yielding higher image quality in SECT-100 kVp and DECT-65 keV abdominopelvic scans compared to SECT-120 kVp using fixed CM volumes.

Incomplete Recovery from the Radiocontrast-Induced Dysregulated Cell Cycle, Adhesion, and Fibrogenesis in Renal Tubular Cells after Radiocontrast (Iohexol) Removal

Contrast-induced nephropathy (CIN) is one of the most common causes of acute kidney injury (AKI). However, management is still limited, and the cellular response to radiocontrast removal for CIN remains unclear. This study aimed to explore the latent effects of iohexol in cultured renal tubular cells with or without the removal of iohexol by medium replacement. HK2 renal tubular cells were subcultured 24 h before use in CIN experiments. Three treatment groups were established: the control, a radiocontrast (iohexol)-only group at 75 mg I/mL (I-75), and iohexol exposure for 24 h with culture medium replacement (I-75/M). Cell cycle arrest, fibrogenic mediator assays, cell viability, cell function, and cell-cycle-related protein expression were compared between groups. Iohexol induced numerous changes in HK2 renal tubular cells, such as enlarged cell shape, cell cycle arrest, increased apoptosis, and polyploidy. Iohexol inhibited the expression of cyclins, CDKs, ZO-1, and E-cadherin but conversely enhanced the expression of p21 and fibrosis-related genes, including TGF-β1, CTGF, collagen I, collagen III, and HIF-1α within 60 hr after the exposure. Except for the recovery from cell cycle arrest and cell cycle gene expression, notably, the removal of iohexol by medium replacement could not fully recover the renal tubular cells from the formation of polyploid cells, the adhesion or spreading, or the expression of fibrosis-related genes. The present study demonstrates, for the first time, that iohexol exerts latent cytotoxic effects on cultured renal tubular cells after its removal, suggesting that these irreversible cell changes may cause the insufficiency of radiocontrast reduction in CIN, which is worth investigating further.

Preventing contrast-induced acute kidney injury with probucol and hydration in patients with coronary heart disease: A systematic review and meta-analysis of randomized controlled trials

BACKGROUND

Preventing contrast-induced acute kidney injury (CI-AKI) is critical because of its association with poor clinical outcomes, including extended hospital stays and increased mortality. The effects of probucol on preventing CI-AKI have been controversial. Therefore, this systematic review and meta-analysis evaluated the influence of probucol combined with hydration on the CI-AKI risk in patients with coronary heart disease undergoing coronary angiography (CAG) or percutaneous coronary intervention (PCI).

METHODS

We retrieved data from the following databases from their inception to May 29, 2022: PubMed, Embase, Web of Science, Cochrane Library, China National Knowledge Infrastructure, Chinese Biomedical Literature Database (Sinomed), Wanfang Database, and Chinese Scientific Journal Database. The methodological quality of the trials was assessed following the Cochrane Handbook guidelines, and Review Manager 5.3 and Stata 14.0 software were used for the data analysis.

RESULTS

We included 14 trials comprising 3306 patients in the analysis. All included trials reported the CI-AKI incidence rate (the primary outcome). Probucol with hydration significantly reduced the CI-AKI incidence compared to hydration alone (odds ratio [OR]: 0.33, 95% confidence interval [CI]: 0.25-0.44, P < .001). Subgroup analyses were performed based on the contrast medium type (iso-osmolality vs low-osmolality contrast medium [LOCM]) and volume (less than or more than 200 mL); the effects of probucol with hydration versus hydration-only on CI-AKI were comparable within each subgroup. Additionally, the serum creatinine (Scr) concentration 24 hours, 48 hours, and 72 hours and the estimated glomerular filtration rate (eGFR) 72 hours after contrast exposure were better in the probucol with hydration group than the hydration-only group. Finally, major clinical adverse events and adverse drug reactions were comparable between the probucol with hydration and hydration-only groups.

CONCLUSION

Probucol with hydration decreases the CI-AKI incidence compared to hydration only in patients with coronary heart disease undergoing CAG or PCI. However, more high-quality, large-sample, multicenter randomized trials are needed to confirm this conclusion.

Hepatic enhancement at computed tomography: is there a dependence on body weight past institutional contrast dosing limits?

BACKGROUND

Although described in product monographs, the maximum contrast media (CM) dose at computed tomography (CT) varies among institutions.

PURPOSE

To investigate whether an upper limit of 40 g of iodine in women and 50 g in men is sufficient or if there is a body weight (BW) dependence of mean hepatic enhancement (MHE) beyond those thresholds.

MATERIAL AND METHODS

At our institution, CM injection duration is fixed to 30 s and dosed 600 mg iodine/kg up to 40 g in women and 50 g in men. Pre- and post-contrast hepatic attenuation values (HU) were retrospectively obtained in 200 women and 200 men with glomerular filtration rate >45 mL/min undergoing 18-flurodeoxyglucose PET-CT (18F-FDG PET-CT) of which half weighed below and half above those dose thresholds using iodixanol 320 mg iodine/mL or iomeprol 400 mg iodine/mL. The correlation between BW and MHE was assessed by simple linear regression.

RESULTS

Weight range was 41-120 kg in women and 47-137 kg in men. There was no significant relationship between MHE and BW in women receiving <40 g (r = -0.05, P = 0.63) or in men receiving <50 g (r = 0.18, P = 0.07). Above those thresholds there was an inverse relationship (r = -0.64, P<0.001 in women and r = -0.30, P<0.002 in men). There was no apparent upper limit where the dependence of hepatic MHE on BW decreased. Hepatosteatosis limited MHE.

CONCLUSION

Adjusting CM to BW diminishes the dependence of MHE on BW. There was no apparent upper limit for the relationship between BW and MHE in heavier patients at CM-enhanced CT.

Service evaluation of radiographer-led vetting and protocoling of Computed Tomography (CT) scan requests in a Singapore public healthcare institution

INTRODUCTION

A service improvement project involving the vetting and protocoling of Computed Tomography (CT) scan requests by qualified CT radiographers was initiated in 2018.

AIM

This study provides a comprehensive evaluation of how a radiographer-led initiative aims to ensure that the CT scan requests received by the Radiology department are clinically appropriate, which in turn will reduce interruptions to the interpretation and reporting of imaging examinations by radiologists, who might otherwise be required to attend to clinically inappropriate and wrongly protocolled CT scan requests.

METHOD

Outpatient CT scan requests received from July to October 2021 were vetted and protocolled by a qualified CT-trained radiographer for parameters which included the appropriateness of the clinical indication, adequacy of patient preparation for the scan, as well as the suitability of the requested examination protocol pertaining to the need for contrast media, multiple contrast-enhanced imaging phases, and the appropriateness of the scan range.

RESULTS

Poor patient preparation and insufficient or inaccurate clinical indications were the most common findings during the vetting process (71%). Out of the 64 CT scan requests with protocol errors, 77% were attributed to contrast media type errors. The odds of incorrect CT scan requests increased with the requesting clinician's rank, while there was no such significant correlation with the clinical specialty of the requesting clinician or the CT scan type.

CONCLUSION

The meticulous vetting of imaging requests helps to ensure that limited imaging hardware resources are allocated to more clinically appropriate cases, correct protocols are applied to requested imaging scans, and that patients undergoing imaging are adequately prepared, thereby enhancing overall patient care.

IMPLICATIONS FOR PRACTICE

Vetting of imaging requests by radiographers, who are capable to make appropriate clinical decisions related to their enhanced level of practice ensures patient safety and optimisation of Radiology resources.

Quercetin improves contrast-induced acute kidney injury through the HIF-1α/lncRNA NEAT1/HMGB1 pathway

CONTEXT

The risk of contrast-induced acute kidney injury (CI-AKI) is increasing and the harm is great. Quercetin is the main active component in Abelmoschus manihot (L.) Medik (Malvaceae) and was reported to reduce the expression of HIF-1α.

OBJECTIVE

We investigate whether quercetin improves the CI-AKI through the HIF-1α/lncRNA NEAT1/HMGB1 pathway.

MATERIALS AND METHODS

HK-2 cells were treated with iohexol (200 mg/mL) for 6 h to establish a CI-AKI model. Quercetin (20 μM) was administered to CI-AKI cells cultured in dishes for 24 h. Cell morphology was observed by a fluorescence microscope. MTT and TUNEL assays were used to detect cell survival rate and apoptosis. Relative mRNA levels were measured by qRT-PCR. Protein levels were detected using western blotting. IL-6 and TNF-α protein levels were tested by Elisa assay. Targeting binding sites of HIF-1α and lncRNA NEAT1 were detected by luciferase assay.

RESULTS

The IC₅₀ value of quercetin was 163.25 μM. The expression levels of HIF-1α, lncRNA NEAT1 and HMGB1 were upregulated in the CI-AKI cell model. Quercetin diminished cell injury and apoptosis via inhibiting HIF-1α. Silencing of HIF-1α targeting lncRNA MEAT1 diminished cell injury and apoptosis. Silencing lncRNA NEAT1 has the same effect via suppressing HMGB1 expression. Collectively, quercetin diminished cell injury and apoptosis in CI-AKI cell model via the inhibition of HIF-1α on lncRNA NEAT1/HMGB1 signalling pathway.

DISCUSSION AND CONCLUSIONS

Quercetin diminished cell injury and apoptosis in CI-AKI cell mode via the inhibition of HIF-1α on the lncRNA NEAT1/HMGB1 signalling pathway, offering a potential novel therapeutic target for CI-AKI therapy.

A Contrast Frugal Approach to Transcatheter Aortic Valve Replacement in Chronic Kidney Disease: A Pilot Study

BACKGROUND

Transcatheter aortic valve replacement (TAVR) is now regarded as a viable treatment option for all cases of severe aortic stenosis (AS). Acute kidney injury (AKI) is common and lowers the survival of patients after TAVR and iodine-based contrast-induced nephropathy (CIN) plays a significant adverse role in AKI. Therefore, in chronic kidney disease (CKD) patients requiring pre-operative evaluation for TAVR, the risk of CIN is of particular concern.

METHODS

It was a single-center study including eight CKD patients who underwent pre-operative evaluation for TAVR with minimized contrast exposure by means of pre-operative contrast-sparing evaluation and intra-operative contrast minimization. All patients had glomerular filtration rate (eGFR) calculated before TAVR and on a follow-up about one month and one year post-operatively to document the impact of this TAVR protocol on prognosis of kidney function in patients with advanced CKD.

RESULTS

New York Heart Association (NYHA) functional classification demonstrated significant improvement of symptomatology (p = 0.0001) by one-year post-TAVR. Patients' mean AS gradient was significantly improved (p = 0.00004) after the TAVR procedure. No significant post-operative paravalvular aortic regurgitation was noted on follow up echocardiogram. eGFR data showed mean eGFR for the group was slightly better (27.38 ml/min/per 1.73 m² BSA vs. 30.38 ml/min/per 1.73 m² BSA) after TAVR.

CONCLUSIONS

"Contrast frugal" approach is feasible and safe for pre-TAVR evaluation and the procedure itself. Our pilot study showed no significant paravalvular leak of the prosthetic valve following this proposed protocol. No statistically significant decrease in eGFR was noted on a one-year follow-up.

Renal Safety and Renin-Angiotensin-Aldosterone System Inhibitors in Patients With Contrast Media Exposure: A Multicenter Randomized Controlled Study

ABSTRACT

There is no clear consensus on the safety of renin-angiotensin-aldosterone system inhibitors in patients with contrast media exposure. We aimed to assess the safety of renin-angiotensin-aldosterone system inhibitors in patients exposed to contrast media at 1-year follow-up. Patients treated with angiotensin-converting enzyme inhibitor/angiotensin receptor blocker (ACEI/ARB) were recruited and randomly divided into 2 groups (1:1 ratio): with ACEI/ARB group (ACEI/ARB continued throughout the study period) and without ACEI/ARB group (ACEI/ARB stopped 24 hours before and continued 48 hours after the procedure). The primary endpoint was contrast-induced acute kidney injury (CI-AKI) and secondary endpoints were major adverse cardiovascular events (MACEs), and the need for renal replacement therapy during hospitalization and at 1-year follow-up. The occurrence rates of CI-AKI were not comparable in the ACEI/ARB group and the without ACEI/ARB group (2.92% and 2.62%, respectively; P = 0.866). No significant between-group differences were found with respect to the frequency of MACEs or renal replacement therapy during hospitalization and at 1-year follow-up. On subgroup analysis, among patients with estimated glomerular filtration rate (eGFR) &lt; 45 mL/min, the incidence of CI-AKI was significantly higher in the ACEI/ARB group [17.95% (14/78) vs. 6.02% (5/83), P = 0.029]. Among patients with eGFR ≥ 45 mL/min, the incidence of CI-AKI was comparable in the 2 groups [0.87% (5/572) vs. 2.12% (12/567), P = 0.094]. The incidence of MACEs and renal replacement therapy was not comparable in the 2 groups, during hospitalization and at 1-year follow-up. ACEI or ARB treatment can safely be continued after exposure to contrast media, but not in patients with eGFR &lt; 45 mL/min.

A risk score model of contrast-induced acute kidney injury in patients with emergency percutaneous coronary interventions

Background

The previously built score models of contrast-induced acute kidney injury (CI-AKI) were principally founded on selective percutaneous coronary intervention (PCI) cases. Our study was to form a risk score model of CI-AKI and make a temporal validation in a population who underwent emergency PCIs.

Methods

We included patients who underwent emergency PCIs from 2013 to 2018 and divided them into the derivation and validation cohorts. Logistic regression analysis was harnessed to create the risk model. In this research, we defined CI-AKI as an increase in serum creatinine (SCr) ≥0.5 mg/dL (44.2 μmol/L) above baseline within seven days following exposure to contrast medium.

Results

A total of 3564 patients who underwent emergency PCIs were enrolled and divided into the derivation (2376 cases) and validation cohorts (1188 cases), with CI-AKI incidence of 6.61 and 5.39%, respectively. By logistic analysis, the CI-AKI risk score model was constituted by 8 variables: female (1 point), history of transient ischemic attack (TIA)/stroke (1 point), left ventricular ejection fraction (LVEF) classification (1 point per class), big endothelin-1 (ET-1) classification (1 point per class), estimated glomerular filtration rate (eGFR) classification (1 point per class), intra-aortic balloon pump (IABP) application (1 point), left anterior descending (LAD) stented (1 point), and administration of diuretic (2 points). The patients could be further divided into three groups: low-risk, moderate-risk, and high-risk groups, in accordance with the risk scores of 3–6, 7–10, and ≥11 points, and to the CI-AKI rates of 1.4, 11.9, and 42.6%. The CI-AKI risk score model performed well in discrimination (C statistic = 0.787, 95% CI: 0.731–0.844) and calibration ability, and showed a superior clinical utility.

Conclusion

We developed a simple CI-AKI risk score model which performs well as a tool for CI-AKI prediction in patients who underwent emergency PCIs.

Prevention of Contrast-Induced Nephropathy After Cardiovascular Catheterization and Intervention With High-Dose Strong Statin Therapy in Japan - The PREVENT CINC-J Study

BACKGROUND

Previous studies have reported that high-dose strong statin therapy reduces the incidence of contrast-induced nephropathy (CIN) in statin naïve patients; however, the efficacy of high-dose strong statins for preventing CIN in real-world clinical practice remains unclear. The aim of this study was to evaluate the efficacy of strong statin therapy in addition to fluid hydration for preventing CIN after cardiovascular catheterization.

METHODS AND RESULTS

This prospective, multicenter, randomized controlled trial included 420 patients with chronic kidney disease who underwent cardiovascular catheterization. They were assigned to receive high-dose pitavastatin (4 mg/day × 4 days) on the day before and of the procedure and 2 days after the procedure (Statin group, n=213) or no pitavastatin (Control group, n=207). Isotonic saline hydration combined with a single bolus of sodium bicarbonate (20 mEq) was scheduled for administration to all patients. In the control group, statin therapy was continued at the same dose as that before randomization. CIN was defined as a ≥0.5 mg/dL increase in serum creatinine or ≥25% above baseline at 48 h after contrast exposure. Before randomization, 83% of study participants were receiving statin treatment. The statin group had a higher incidence of CIN than the control group (3.0% vs. 0%, P=0.01). The 12-month rate of major adverse cardiovascular events was similar between the 2 groups.

CONCLUSIONS

High-dose pitavastatin increases the incidence of CIN in this study population.

Gray-Scale, Color Doppler, Spectral Doppler, and Contrast-Enhanced Renal Artery Ultrasound: Imaging Techniques and Features

Renal artery stenosis (RAS) is increasingly being detected in elderly patients as life expectancy increases. RAS induces hypertension or reduces renal function. Computed tomography or magnetic resonance angiography are objective in detecting RAS but may cause iodine-induced nephrotoxicity or nephrogenic systemic fibrosis in patients with RAS. Ultrasound (US) is, by contrast, a noninvasive and real-time imaging modality useful in patients with reduced renal function. Renal US is not as sensitive for detecting RAS because this technique indirectly assesses the renal artery by analyzing intrarenal hemodynamic changes. Although, ideally, US would be used to directly evaluate the renal artery, its current utility for RAS detection remains unclear. The purpose of this review is to introduce how to assess renal artery with US, to describe imaging features of renal artery US, to compare renal artery US and renal US, and to show how to perform work-up in patients in whom RAS is suspected.

Contrast Induced Nephropathy: Efficacy of matched hydration and forced diuresis for prevention in patients with impaired renal function undergoing coronary procedures-CINEMA trial

BACKGROUND

Matched hydration and forced diuresis (MHFD) using the RenalGuard device has been shown to reduce contrast induced nephropathy (CIN) following coronary interventions.

AIM

To evaluate the potential benefits of a non-automated MHFD protocol compared to current hydration protocol in prevention of CIN in patients with CKD.

METHODS

A total of 1,205 patients were randomized to either non-automated MHFD group (n = 799) or intravenous hydration control group (n = 406). The MHFD group received 250 ml IV normal saline over 30 min before the coronary procedure followed by 0.5 mg/kg IV furosemide. Hydration infusion rate was manually adjusted to replace the patient's urine output. When urine output rate reached > 300 ml/h, patients underwent coronary procedure. Matched fluid replacement was maintained during the procedure and for 4-hour post-treatment. CIN was defined conventionally as ≥ 25% or ≥ 0.5 mg/dl rise in serum creatinine over baseline.

RESULTS

CIN occurred in 121 of 1,205 (10.0%) patients in our study. With respect to the primary outcome, 64 (8.01%) of the MHFD patients developed CIN compared with 57 (14.04%) of the control group (p < 0.001).

CONCLUSIONS

A non-automated MHFD protocol is an effective and safe method for the prevention of CIN in patients with CKD.

Incidence and Risk Factors of Contrast-Induced Acute Kidney Injury in Sudanese Patients Undergoing Coronary Angiography: A Descriptive Prospective Study

BACKGROUND

Contrast-induced acute kidney injury (CI-AKI) has been reported to be the third most common cause of hospital-acquired acute kidney injury (AKI) and is associated with significant morbidity and mortality.

OBJECTIVES

This study aimed to assess the incidence and risk factors of CI-AKI in Sudanese patients undergoing coronary angiography.

METHODS

The study was a descriptive, prospective, hospital-based study conducted at Alshaab Hospital between January and April 2019. A total of 163 patients undergoing coronary angiography were enrolled, and a checklist was used to collect data. Chi-square and regression analyses were performed to identify the risk factors of CI‑AKI. CI‑AKI was defined as a rise in serum creatinine ≥25% above baseline within three days after percutaneous coronary angiography (PCA).

RESULTS

CI‑AKI incidence in patients undergoing coronary angiography was 31.9% (52/163). Among independent variables, diabetes mellitus, the type of coronary angiography, and the volume of contrast medium were statistically significantly (p-value ˂ 0.05) associated with CI-AKI development. Logistic analysis showed that diabetes (odds ratio (OR): 15.2; 95% CI: 6.771-33.974; p = 0.001), percutaneous coronary intervention (PCI) (OR: 2.4; 95% CI: 1.168-4.901; p = 0.017), and the volume of contrast medium (OR 2.1; 95% CI: 1.440-3.054; p = 0.001) were independent predictors correlated to CI‑AKI development.

CONCLUSION

The incidence of CI-AKI is 31.9%, and diabetes mellitus, PCI, and high volume of contrast medium are associated with a higher risk of CI-AKI in patients undergoing coronary angiography.

Lean body weight-adjusted intravenous iodinated contrast dose for abdominal CT in dogs reduces interpatient enhancement variability while providing diagnostic quality organ enhancement

Contrast-enhanced computed tomography (CECT) is increasingly used to screen for abdominal pathology in dogs, and the contrast dose used is commonly calculated as a linear function of total body weight (TBW). Body fat is not metabolically active and contributes little to dispersing or diluting contrast medium (CM) in the blood. This prospective, analytic, cross-section design pilot study aimed to establish the feasibility of intravenous CM dosed according to lean body weight (LBW) for abdominal CECT in dogs compared to TBW. We hypothesized that when dosing intravenous CM according to LBW, studies will remain at diagnostic quality, there will be a reduced interindividual contrast enhancement (CE) variability, and there will be less change to heart rate and blood pressure in dogs compared to when administering CM calculated on TBW. Twelve dogs had two CECT studies with contrast doses according to TBW and LBW at least 8 weeks apart. Interindividual organ and vessel CE variability, diagnostic quality of the studies, and changes in physiological status were compared between protocols. The LBW-based protocol provided less variability in the CE of most organs and vessels (except the aorta). When dosed according to LBW, liver enhancement was positively associated with grams of iodine per kg TBW during the portal venous phase (P = 0.046). There was no significant difference in physiological parameters after CM administration between dosing protocols. Our conclusion is that a CM dose based on LBW for abdominal CECT lowers interindividual CE variability and is effective at maintaining studies of diagnostic quality.

Effect of Alvarado Score on the Negative Predictive Value of Nondiagnostic Ultrasound for Acute Appendicitis

Background:

The purposes of this study were to calculate the negative predictive value (NPV) of nondiagnostic ultrasound (US) in patients with suspected appendicitis and to identify the clinical factors that were associated with the nondiagnostic US.

Methods:

We conducted a retrospective review of 412 patients who had graded-compression appendiceal US performed during January 2017 and December 2017. The NPV of the nondiagnostic US in combination with clinical parameters was calculated. Multivariate regression analysis was used to determine the independent predictors for the nondiagnostic US.

Results:

The US exam was nondiagnostic in 64.8% of the patients, giving an NPV of 70.8%. The NPV of nondiagnostic US increased to 96.2% in patients who had an Alvarado score of <5. The patients who did not have migratory pain, did not have leukocytosis, and had a pain score of <7 were more likely to have a nondiagnostic US study (P < 0.001).

Conclusion:

Alvarado score had an inverse effect on the NPV of nondiagnostic appendiceal US. Patients who had nondiagnostic US and Alvarado score of <5 were very unlikely to have appendicitis. Active clinical observation or re-evaluation rather than immediate computed tomography may be a safe alternative approach in these low-risk patients. However, the Alvarado score itself was not a predictive factor of nondiagnostic US. The absence of migratory pain, absence of leukocytosis, and low pain score were the independent predictors of nondiagnostic appendiceal US.

Anemia is associated with increased risk of contrast‑induced acute kidney injury: A Systematic Review and Meta-analysis

Previous studies have identified numerous risk factors of contrast-induced acute kidney injury (CI-AKI) in patients undergoing coronary angiography. However, the association between anemia and CI-AKI remains conflicting. Thus, we conducted a meta-analysis to further clarify the relationship between anemia and CI-AKI. PubMed, EMBASE and Web of Science were systematically searched from inception to June 2020 to identify eligible studies. The pooled odds ratios (ORs) with 95% confidence intervals (CIs) were used to estimate the correlation between anemia and CI-AKI. The potential publication bias was estimated using funnel plot and Begg's test. A total of 13 studies (five case-control studies and eight cohort studies) comprising 27,135 patients were included. The pooled results showed that anemia was a significant risk factor of CI-AKI (OR, 1.82; 95% CI, 1.27-2.61). Moreover, the results of subgroup analyses and sensitivity analyses were basically consistent with the overall pooled result. Funnel plot and Begg's test indicated that there existed potential publication bias, but the result of trim and filled analysis showed that the pooled results kept stable after adding 'missing' studies. This meta-analysis suggested that anemia may be correlated with an increased incidence of CI-AKI in patients undergoing coronary angiography. However, our conclusions should be interpreted with caution due to some limitations. Therefore, further high-quality trials should be conducted to confirm our findings.

Does the cardiovascular drug levosimendan prevent iodinated contrast medium nephrotoxicity with glycerol aggravation in rats?

Background

We investigated whether levosimendan prevents contrast medium nephrotoxicity with glycerol aggravation in rats.

Methods

Forty-eight Wistar albino rats were assigned to eight groups (n = 6 × 8). No medication was administered to group I (controls); glycerol (intramuscular injection of 25% glycerol, 10 mL/kg) group II; intravenous iohexol 10 mL/kg to group III; glycerol and iohexol to group IV; iohexol and intraperitoneal levosimendan 0.25 mg/kg to group V; glycerol, iohexol, and levosimendan 0.25 mg/kg to group VI; iohexol and levosimendan 0.5 mg/kg to group VII; and glycerol, iohexol, and levosimendan 0.5 mg/kg to group VIII. One-day water withdrawal and glycerol injection prompted renal damage; iohexol encouraged nephrotoxicity; levosimendan was administered 30 min after glycerol injection and continued on days 2, 3, and 4. The experiment was completed on day 5. Serum blood urea nitrogen (BUN) and creatinine levels, superoxide dismutase (SOD) activity, glutathione (GSH), malondialdehyde (MDA) levels, tumour necrosis factor-α (TNF-α), nuclear factor kappa ß (NFK-ß), interleukin 6 (IL-6), and histopathological marks were assessed. One-way analysis of variance and Duncan’s multiple comparison tests were used.

Results

Levosimendan changed serum BUN (p = 0.012) and creatinine (p = 0.018), SOD (p = 0.026), GSH (p = 0.012), and MDA (p = 0.011). Levosimendan significantly downregulated TNF-α (p = 0.022), NFK-ß (p = 0.008), and IL-6 (p = 0.033). Histopathological marks of hyaline and haemorrhagic cast were improved in levosimendan-injected groups.

Conclusion

Levosimendan showed nephroprotective properties due to its vasodilator, oxidative distress decreasing and inflammatory cytokine preventing belongings.

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.

Significance of serum FGF-23 for risk assessment of contrast-associated acute kidney injury and clinical outcomes in patients undergoing coronary angiography

Background

Fibroblast growth factor (FGF)-23 levels rise as kidney function declines. Whether elevated FGF-23 levels are associated with an increased risk for contrast-associated acute kidney injury (CA-AKI) and major adverse cardiovascular events (MACE) in patients undergoing coronary angiography remain uncertain.

Methods

In total, 492 patients receiving coronary angiography were enrolled. Their serum FGF-23 levels were measured before administration of contrast media. The occurrence of CA-AKI was defined as a rise in serum creatinine of 0.5 mg/dL or a 25% increase from the baseline value within 48 h after the procedure. All patients were followed up for at least 1 year or until the occurrence of MACE including death, nonfatal myocardial infarction (MI), and ischemic stroke.

Results

Overall, CA-AKI occurred in 41 (8.3%) patients. During a median follow-up of 2.6 years, there were 24 deaths, 3 nonfatal MIs, and 7 ischemic strokes. Compared with those in the lowest FGF-23 tertile, individuals in the highest FGF-23 tertile had a significantly higher incidence of CA-AKI (P < 0.001) and lower incidence of MACE-free survival (P = 0.001). In multivariate regression analysis, higher FGF-23 level was found to be independently associated with a graded risk for CA-AKI (OR per doubling, 1.90; 95% CI 1.48–2.44) and MACE (HR per doubling, 1.25; 95% CI 1.02–1.52).

Conclusions

Elevated FGF-23 levels were associated with an increased risk for CA-AKI and future MACE among patients undergoing coronary angiography. FGF-23 may play a role in early diagnosis of CA-AKI and predicting clinical outcomes after coronary angiography.

Accuracy of registration techniques and vascular imaging modalities in fusion imaging for aortic endovascular interventions: a phantom study

Background

This study aimed to assess the error of different registration techniques and imaging modalities for fusion imaging of the aorta in a standardized setting using a anthropomorphic body phantom.

Materials and methods

A phantom with the 3D printed vasculature of a patient suffering from an infrarenal aortic aneurysm was constructed. Pulsatile flow was generated via an external pump. CTA/MRA of the phantom was performed, and a virtual 3D vascular model was computed. Subsequently, fusion imaging was performed employing 3D-3D and 2D-3D registration techniques. Accuracy of the registration was evaluated from 7 right/left anterior oblique c-arm angulations using the agreement of centerlines and landmarks between the phantom vessels and the virtual 3D virtual vascular model. Differences between imaging modalities were assessed in a head-to-head comparison based on centerline deviation. Statistics included the comparison of means ± standard deviations, student’s t-test, Bland-Altman analysis, and intraclass correlation coefficient for intra- and inter-reader analysis.

Results

3D-3D registration was superior to 2D-3D registration, with the highest mean centerline deviation being 1.67 ± 0.24 mm compared to 4.47 ± 0.92 mm. The highest absolute deviation was 3.25 mm for 3D-3D and 6.25 mm for 2D-3D registration. Differences for all angulations between registration techniques reached statistical significance. A decrease in registration accuracy was observed for c-arm angulations beyond 30° right anterior oblique/left anterior oblique. All landmarks (100%) were correctly positioned using 3D-3D registration compared to 81% using 2D-3D registration. Differences in accuracy between CT and MRI were acceptably small. Intra- and inter-reader reliability was excellent.

Conclusion

In the realm of registration techniques, the 3D-3D method proved more accurate than did the 2D-3D method. Based on our data, the use of 2D-3D registration for interventions with high registration quality requirements (e.g., fenestrated aortic repair procedures) cannot be fully recommended. Regarding imaging modalities, CTA and MRA can be used equivalently.

Renal Safety of Repeated Intravascular Administrations of Iodinated or Gadolinium-Based Contrast Media within a Short Interval

OBJECTIVE

We aimed to investigate whether repeated intravascular administration of iodinated contrast media (ICM) or gadolinium-based contrast agents (GBCAs) within a short interval was associated with an increased risk of post-contrast acute kidney injury (PC-AKI).

MATERIALS AND METHODS

This retrospective study included 300 patients (mean age ± standard deviation, 68.5 ± 8.1 years; 131 male and 169 female) who had undergone at least one ICM-enhanced perfusion brain CT scan, had their baseline and follow-up serum creatinine levels available, and had not undergone additional contrast-enhanced examinations 72 hours before and after a time window of interest were included. The study population was divided into three groups: single-dose group and groups of patients who had received multiple contrast administrations in the time window of interest with the minimum contrast repeat interval either within 4 hours (0-4-hour group) or between 4 to 48 hours (4-48-hour group). Multivariable logistic regression analysis was conducted to evaluate the association between AKI and repeated ICM administrations. A similar supplementary analysis was performed including both ICM and GBCA.

RESULTS

When ICM was only considered ignoring GBCA, among 300 patients, 207 patients received a single dose of ICM, 58 had repeated doses within 4 hours (0-4-hour group), and 35 patients had repeated doses between 4 to 48 hours (4-48-hour group). Most patients (> 95%) had a baseline estimated glomerular filtration rate (eGFR) of ≥ 30 mL/min/1.73 m². AKI occurred in 7.2%, 13.8%, and 8.6% of patients in the single-dose, 0-4-hour, and 4-48-hour groups, respectively. In the 0-4-hour and 4-48-hour groups, additional exposure to ICM was not associated with AKI after adjusting for comorbidities and nephrotoxic drugs (all p values > 0.05).

CONCLUSION

Repeated intravascular administrations of ICM within a short interval did not increase the risk of AKI in our study patients suspected of acute stroke with a baseline eGFR of ≥ 30 mL/min/1.73 m².

Utility of measuring serum creatinine to detect renal compromise in ED patients receiving IV contrast-enhanced CT scan

OBJECTIVE

The objectives of this study are to determine the efficacy of a roster of clinical factors in identifying risk for renal insufficiency in emergency department (ED) patients requiring intravenous contrast-enhanced CT scan (IVCE-CT) and to help mitigate potential for developing contrast-induced nephropathy (CIN).

METHODS

A review was conducted of consecutive ED patients who received IVCE-CT during a 4-month period in our urban ED. The values of ED serum creatinine (SCr) performed were tabulated. The medical records of all patients with an elevated SCr (> 1.4 mg/dL) were reviewed to determine and correlate the presence of clinical risk factors for underlying renal insufficiency.

RESULTS

During the 4-month study period, there were 2260 consecutive cases who received IVCE-CT; of these, 2250 (99.6%) had concomitant measurement of SCr. Elevated SCr occurred in 141 patients (6.2%); of these, 75 had a SCr > 2 mg/dL. In all, 139/141 (98.6%) with an elevated SCr had an underlying chronic or acute medical condition identified by medical record review which potentially compromised renal function, including chronic renal disease, diabetes mellitus, HIV infection, cancer, hypertension, congestive heart failure, sepsis/septic shock, chronic alcoholism, and sickle cell disease. Two patients with no identified risk factor each had (mildly) elevated SCr; both had a normal SCr measured post-CT scan. The total cost of performing serum basic metabolic panel to measure SCr in all patients during the 4-month study period was $94,500.

CONCLUSIONS

Elevated SCr is rarely present in ED patients without recognized risk factors who receive IVCE-CT scan. The vast majority with underlying renal insufficiency are readily identified by a review of the patient's medical history and/or clinical findings. Routine SCr measurement on all ED patients regardless of risk stratification prior to IVCE imaging is neither time nor cost-effective.

Contrast-Induced Nephropathy: A Review of Mechanisms and Risks

Radiological procedures utilizing intravenous iodinated contrast agents are being widely utilized for both therapeutic and diagnostic purposes. This has resulted in an increasing incidence of procedure-related, contrast-induced nephropathy (CIN). CIN is commonly defined as a decline in kidney function occurring in a narrow time window after administration of iodinated contrast agents. Although self-limiting in most cases, CIN carries a risk of more permanent renal insufficiency, dialysis, and death. It remains a common and serious complication among at-risk patients after exposure of contrast agents. Therefore, it is important to identify patients who are at risk during early stages to implement preventative strategies to decrease the incidence of CIN. Minimizing the amount of contrast administered and providing adequate hydration are the cornerstones of an effective preventative approach. This review focuses on the basic concepts of CIN and summarizes the current understanding of its pathophysiology. In addition, it provides practical recommendations with respect to CIN prevention and management.

Erythropoietin Attenuates Experimental Contrast-Induced Nephrology: A Role for the Janus Kinase 2/Signal Transducer and Activator of Transcription 3 Signaling Pathway

The aim of the present study was to investigate the effect of erythropoietin (EPO) on contrast-induced nephrology (CIN) in vivo and in vitro. Male C57BL/6J mice were divided into four groups: control, CIN (iohexol 6.0 g/kg), EPO (3,000 IU/kg), and CIN+EPO. Hematoxylin and eosin (H&E) staining and biochemical index analyses were performed to evaluate renal injury. The cellular proliferation rate was detected using the Cell Counting Kit-8 (CCK-8) assay. In addition, a terminal deoxynucleotidyl transferase-mediated dUTP nick end labeling (TUNEL) assay and flow cytometric assay were used to assess the apoptosis of tissue and cells, respectively. Renal protein expression associated with apoptosis, pyroptosis, and signaling pathways was determined by Western blot (WB) assays for tissues and cells. The results showed that EPO significantly decreased serum creatinine, blood urea nitrogen, and cystatin C levels and alleviated renal histological changes in vivo. The protein levels of Janus kinase 2/signal transducer and activator of transcription 3 (JAK2/STAT3) signaling pathway components were overexpressed in the EPO treatment group. Furthermore, EPO suppressed the cell apoptosis and pyroptosis; decreased the protein levels of cleaved caspase-3, Bax, gasdermin D (GSDMD), and caspase-1; and enhanced the expression of Bcl-2. In summary, EPO could exert renoprotective effect by activating the JAK2/STAT3 signaling pathway, which may be a novel potential therapy for the treatment of CIN in the clinic.

Revising the Maximal Contrast Dose for Predicting Acute Kidney Injury following Coronary Intervention

INTRODUCTION

The maximal allowable contrast dose (MACD = 5 × body weight/serum creatinine) is an empiric equation that has been used and validated in several studies to mitigate the risk of contrast-induced acute kidney injury (CI-AKI). However, coefficient 5 (referred to as factor K) was empirically devised and never disputed. The aim of this study was to refine the MACD equation for the prediction of CI-AKI following percutaneous coronary interventions (PCIs).

METHODS

This is a single-center, retrospective cohort study of adults undergoing PCI. Electronic medical records were reviewed to identify patients who underwent PCI between 2010 and 2019, derived from the National Cardiovascular Data Registry Cath-PCI registry for our hospital. Factor K (defined as contrast volume × serum creatinine/body weight) was calculated for every patient. A receiver operating characteristic (ROC) curve was constructed, and the Youden index was used to identify the optimal cut-off value for factor K in predicting severe (stages 2-3) CI-AKI.

RESULTS

Of the 3,506 patients undergoing PCI, 255 (7.2%) developed CI-AKI, and 68 (26.7%) of the 255 experienced severe AKI. Factor K predicted all-stage CI-AKI (area under the ROC curve 0.649; 95% CI 0.611, 0.686) but had better performance for predicting severe (stages 2-3) AKI (0.736; 95% CI 0.674, 0.800). The optimal cut-off value for factor K in predicting severe CI-AKI was 2.5, with a corresponding sensitivity of 68.7% and specificity of 70.5%. On subgroup analyses, optimal cut-off values for factor K for high-risk groups were not significantly different from those of low-risk groups.

CONCLUSION

Our study indicates that factor K in the MACD equation is an independent risk factor for the development of severe CI-AKI, with an optimal cut-off value of 2.5. If our findings are validated, the MACD equation should be revised to incorporate the coefficient of 2.5 instead of 5.

Long-Term Mortality Related to Acute Kidney Injury Following Intracerebral Hemorrhage: A 10-Year (2010-2019) Retrospective Study

OBJECTIVES

Acute kidney injury (AKI) following intracerebral hemorrhage (ICH) is an intractable medical complication and an independent predictor of short-term mortality. However, the correlation between AKI and long-term mortality has not been fully investigated. The aim of the present study was to determine the relationship between AKI following ICH and long-term mortality in a 10-year (2010-2019) retrospective cohort.

MATERIALS AND METHODS

A total of 1449 ICH patients were screened and enrolled at the Department of Neurosurgery, Southwest Hospital, Third Military Medical University (Army Medical University) from January 2010 to December 2016. The endpoint for follow-up was May 31, 2019. The estimated all-cause mortality was determined using Cox proportional hazard regression models.

RESULTS

Among 1449 ICH patients, 136 (9.4%) suffered from AKI, and the duration of follow-up was a median of 5.1 years (IQR 3.2-7.2). The results indicated that the risk factors for AKI without preexisting chronic kidney disease (CKD) in the multivariable analysis were age (p = 0.002), nephrotoxic antibiotics (p = 0.000), diabetes mellitus (p = 0.005), sepsis (p = 0.000), antiplatelet therapy (p = 0.002), infratentorial hemorrhage (p = 0.000) and ICH volume (p = 0.003). Age (p = 0.008), ACEIs/ARBs (p = 0.010), nephrotoxic antibiotics (p = 0.014), coronary artery disease (p = 0.009), diabetes mellitus (p = 0.014), hypertension (p = 0.000) and anticoagulant therapy (p = 0.000) were independent predictors of AKI with preexisting CKD. Meanwhile, the data demonstrated that the estimated all-cause mortality was significantly higher in ICH patients with AKI without preexisting CKD (HR 4.208, 95% CI 2.946-6.011; p = 0.000) and in ICH patients with AKI with preexisting CKD (HR 2.470, 95% CI 1.747-3.492; p = 0.000) than in those without AKI.

CONCLUSIONS

AKI is a long-term independent predictor of mortality in ICH patients. Thus, renal function needs to be routinely determined in ICH patients during clinical practice.

Towards Personalised Contrast Injection: Artificial-Intelligence-Derived Body Composition and Liver Enhancement in Computed Tomography

In contrast-enhanced computed tomography, total body weight adapted contrast injection protocols have proven successful in achieving a homogeneous enhancement of vascular structures and liver parenchyma. However, because solid organs have greater perfusion than adipose tissue, the lean body weight (fat-free mass) rather than the total body weight is theorised to cause even more homogeneous enhancement. We included 102 consecutive patients who underwent a multiphase abdominal computed tomography between March 2016 and October 2019. Patients received contrast media (300 mgI/mL) according to bodyweight categories. Using regions of interest, we measured the Hounsfield unit (HU) increase in liver attenuation from unenhanced to contrast-enhanced computed tomography. Furthermore, subjective image quality was graded using a four-point Likert scale. An artificial intelligence algorithm automatically segmented and determined the body compositions and calculated the percentages of lean body weight. The hepatic enhancements were adjusted for iodine dose and iodine dose per total body weight, as well as percentage lean body weight. The associations between enhancement and total body weight, body mass index, and lean body weight were analysed using linear regression. Patients had a median age of 68 years (IQR: 58–74), a total body weight of 81 kg (IQR: 73–90), a body mass index of 26 kg/m² (SD: ±4.2), and a lean body weight percentage of 50% (IQR: 36–55). Mean liver enhancements in the portal venous phase were 61 ± 12 HU (≤70 kg), 53 ± 10 HU (70–90 kg), and 53 ± 7 HU (≥90 kg). The majority (93%) of scans were rated as good or excellent. Regression analysis showed significant correlations between liver enhancement corrected for injected total iodine and total body weight (r = 0.53; p < 0.001) and between liver enhancement corrected for lean body weight and the percentage of lean body weight (r = 0.73; p < 0.001). Most benefits from personalising iodine injection using %LBW additive to total body weight would be achieved in patients under 90 kg. Liver enhancement is more strongly associated with the percentage of lean body weight than with the total body weight or body mass index. The observed variation in liver enhancement might be reduced by a personalised injection based on the artificial-intelligence-determined percentage of lean body weight.

Contrast-associated acute kidney injury: An update of risk factors, risk factor scores, and preventive measures

As lifespans lengthen, age-related diseases such as cardiovascular disease and diabetes are becoming more prevalent. Correspondingly, the use of contrast agents for medical imaging is also becoming more common, and there is increasing awareness of contrast-associated acute kidney injury (CA-AKI). There is no specific treatment for CA-AKI, and clinicians currently focus on prevention, interventions that alter its pathogenesis, and identification of risk factors. Although the incidence of CA-AKI is low in the general population, the risk of CA-AKI can reach 20% to 30% in patients with multiple risk factors. Many models have been applied in the clinic to assess the risk factors for CA-AKI, enable identification of high-risk groups, and improve clinical management. Hypotonic or isotonic contrast media are recommended to prevent CA-AKI in high-risk patients. Patients with risk factors should avoid using contrast media multiple times within a short period of time. All nephrotoxic drugs should be stopped at least 24 h before the administration of contrast media in high-risk populations, and adequate hydration is recommended for all patients. This review summarizes the pathophysiology of CA-AKI and the progress in diagnosis and differential diagnosis; updates the risk factors and risk factor scoring systems; reviews the latest advances related to prevention and treatment; discusses current problems in epidemiological studies; and highlights the importance of identifying high-risk subjects to control modifiable risk factors and use of a rating scale to estimate the risk and implement appropriate prevention strategies.

Findings on intraprocedural non-contrast computed tomographic imaging following hepatic artery embolization are associated with development of contrast-induced nephropathy

BACKGROUND

Contrast-induced nephropathy (CIN) is a reversible form of acute kidney injury that occurs within 48-72 h of exposure to intravascular contrast material. CIN is the third leading cause of hospital-acquired acute kidney injury and accounts for 12% of such cases. Risk factors for CIN development can be divided into patient- and procedure-related. The former includes pre-existing chronic renal insufficiency and diabetes mellitus. The latter includes high contrast volume and repeated exposure over 72 h. The incidence of CIN is relatively low (up to 5%) in patients with intact renal function. However, in patients with known chronic renal insufficiency, the incidence can reach up to 27%.

AIM

To examine the association between renal enhancement pattern on non-contrast enhanced computed tomographic (CT) images obtained immediately following hepatic artery embolization with development of CIN.

METHODS

Retrospective review of all patients who underwent hepatic artery embolization between 01/2010 and 01/2011 (n = 162) was performed. Patients without intraprocedural CT imaging (n = 51), combined embolization/ablation (n = 6) and those with chronic kidney disease (n = 21) were excluded. The study group comprised of 84 patients with 106 procedures. CIN was defined as 25% increase above baseline serum creatinine or absolute increase ≥ 0.5 mg/dL within 72 h post-embolization. Post-embolization CT was reviewed for renal enhancement patterns and presence of renal artery calcifications. The association between non-contrast CT findings and CIN development was examined by Fisher’s Exact Test.

RESULTS

CIN occurred in 11/106 (10.3%) procedures (Group A, n = 10). The renal enhancement pattern in patients who did not experience CIN (Group B, n = 74 with 95/106 procedures) was late excretory in 93/95 (98%) and early excretory (EE) in 2/95 (2%). However, in Group A, there was a significantly higher rate of EE pattern (6/11, 55%) compared to late excretory pattern (5/11) (P < 0.001). A significantly higher percentage of patients that developed CIN had renal artery calcifications (6/11 vs 20/95, 55% vs 21%, P = 0.02).

CONCLUSION

A hyperdense renal parenchyma relative to surrounding skeletal muscle (EE pattern) and presence of renal artery calcifications on immediate post-HAE non-contrast CT images in patients with low risk for CIN are independently associated with CIN development.

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.

The Mechanism of Contrast-Induced Acute Kidney Injury and Its Association with Diabetes Mellitus

Contrast-induced acute kidney injury (CI-AKI) is the third most common hospital-acquired AKI after AKI induced by renal perfusion insufficiency and nephrotoxic drugs, taking great adverse effects on the prognosis and increasing hospital stay and medical cost. Diabetes nephropathy (DN) is a common chronic complication of DM (diabetes mellitus), and DN is an independent risk factor for chronic kidney disease (CKD) and CI-AKI. The incidence of CI-AKI significantly increases in patients with renal injury, especially in DM-related nephropathy. The etiology of CI-AKI is not fully clear, and research studies on how DM becomes a facilitated factor of CI-AKI are limited. This review describes the mechanism from three aspects. ① Pathophysiological changes of CI-AKI in kidney under high-glucose status (HGS). HGS can enhance the oxidative stress and increase ROS which next causes stronger vessel constriction and insufficient oxygen supply in kidney via vasoactive substances. HGS also aggravates some ion pump load and the latter increases oxygen consumption. CI-AKI and HGS are mutually causal, making the kidney function continue to decline. ② Immunological changes of DM promoting CI-AKI. Some innate immune cells and pattern recognition receptors (PRRs) in DM and/or DN may respond to some damage-associated molecular patterns (DAMPs) formed by CI-AKI. These effects overlap with some pathophysiological changes in hyperglycemia. ③ Signaling pathways related to both CI-AKI and DM. These pathways involved in CI-AKI are closely associated with apoptosis, inflammation, and ROS production, and some studies suggest that these pathways may be potential targets for alleviating CI-AKI. In conclusion, the pathogenesis of CI-AKI and the mechanism of DM as a predisposing factor for CI-AKI, especially signaling pathways, need further investigation to provide new clinical approaches to prevent and treat CI-AKI.

Pathophysiology of Contrast-Induced Acute Kidney Injury (CIAKI)

Contrast-induced acute kidney injury (CIAKI) is a severe complication associated with the use of iodinated contrast media (CM); a sudden but potentially reversible fall in glomerular filtration rate (GFR) typically occurring 48-72 hours after CM administration. Principal risk factors related with the presentation of CIAKI are preexisting chronic kidney disease and diabetes mellitus. Studies on CIAKI present considerable complexity because of differences in CM type and dose, controversies in definition and baseline comorbidities. Despite that, it should be noted that CIAKI poses a serious health problem because it is a very common cause of hospitalacquired AKI, linked to increased morbidity and mortality and utilizing growing healthcare resources. The pathogenesis of CIAKI is heterogeneous and, thus, is incompletely understood. Three basic mechanisms appear to simultaneously occur for CIAKI development: Renal vasoconstriction and medullary hypoxia, tubular cell toxicity and reactive oxygen species formation. The relative contribution of each one of these mechanisms is unknown but they ultimately lead to epithelial and endothelial cell apoptosis and GFR reduction. Further research is needed in order to better clarify CIAKI pathophysiology and accordingly introduce effective preventive and therapeutic strategies.

Risk for Contrast-Induced Nephropathy in Elderly Trauma Patients

The objective of this study was to determine if elderly trauma patients are at risk for contrast-induced nephropathy (CIN). A retrospective study was conducted identifying 362 patients 65 years and older in our Level I trauma center who received computerized tomography (CT) scans with intravenous contrast. CIN was defined as a 25 per cent increase in serum creatinine levels or a 0.5 mg/dL increase above baseline after CT. History of diabetes mellitus, hospital length of stay, intensive care unit length of stay, Injury Severity Score (ISS), and age were recorded. Eighteen per cent (21 of 118) of the patients had a peak in creatinine, 12 per cent (14 of 118) peaked and returned to baseline, and 6 per cent (7 of 118) peaked and stayed high. Pre-CT elevated creatinine, diabetes mellitus, increased hospital length of stay, ISS, and age show little association to CIN. The data suggest that CIN in elderly trauma patients is rare, regardless of history of diabetes mellitus, age, creatinine, high ISS, or result in higher length of stay. Therefore, there is little justification for the delay in diagnosis to assess a patient's renal susceptibility.