Nephrotoxicity of iodinated contrast media: From pathophysiology to prevention strategies

Assessing the Role of Bioelectrical Impedance Vector Analysis in Prognosis and Prevention of Contrast-Associated Acute Kidney Injury After Percutaneous Coronary Intervention

This study evaluated the impact of Bioelectrical Impedance Vector Analysis (BIVA)-guided hydration therapy on contrast-associated acute kidney injury (CA-AKI) in patients undergoing percutaneous coronary intervention (PCI). From April 2022 to January 2023, this prospective study at the Eastern General Hospital of the Chinese People's Liberation Army involved 902 adults with stable coronary artery disease (CAD) scheduled for PCI. BIVA measurements were performed pre-contrast, followed by a standard hydration regimen. The study focused on the development of CA-AKI and major adverse cardiovascular events (MACE, including all-cause death, nonfatal myocardial infarction, and target vessel revascularization) within 1 year post-PCI. Among the 902 patients (average age: 60.8 years, 65.2% men), CA-AKI post-PCI was observed in 10.8%. Those with CA-AKI had more comorbidities and higher baseline creatinine levels. The contrast volume-to-estimated Glomerular Filtration Rate (eGFR) ratio was higher in CA-AKI patients, with a significantly increased resistance/height ratio (R/H). High R/H values correlated with a greater risk of MACE and all-cause mortality within a year. The study underscores the importance of BIVA-guided hydration therapy and R/H ratio in predicting CA-AKI in PCI patients with stable CAD. Incorporating R/H ratio assessments may enhance pre-procedural risk assessment and improve long-term outcomes (P = .0017).

NMR-based metabolomic analysis of plasma from elderly patients with CVD before and after using contrast media

Contrast-induced acute kidney injury (CI-AKI) is a growingly common kidney problem caused by medical procedures involving contrast media (CM), especially in older patients with existing health issues. It is crucial to pinpoint potential biomarkers for the early detection of CI-AKI. Previously, we observed that iodixanol affects glucose, choline, and glutathione metabolism in endothelial cells under laboratory conditions. In this study, we used 1H NMR-based metabolomics to examine the metabolic changes in the blood plasma of elderly patients with cardiovascular disease (CVD) before and after receiving iodixanol. We identified altered metabolites in plasma 24 and 48 h after iodixanol injection compared to levels before injection. Notably, metabolites such as glucose, unsaturated fatty acids (UFA), low-density lipoprotein (LDL)/very low-density lipoprotein (VLDL), pyruvate, choline, and glycine showed potential as biomarkers at 24 h post-injection compared to levels before injection. Similarly, glucose, pyruvate, lactate, choline, and glycine in plasma could serve as potential biomarkers at 48 h post-injection. Iodixanol notably affected pathways related to glycolysis, fatty acid breakdown, and amino acid metabolism according to our metabolic pathway analysis. The altered levels of specific metabolites in plasma could be indicative of CM-induced kidney injury. Overall, this research aids in understanding the physiological mechanisms involved and in identifying early biomarkers and prevention strategies for CI-AKI.

Development and validation of a medication-based risk prediction model for acute kidney injury in older outpatients

BACKGROUND

Older adults are at an increased risk of acute kidney injury (AKI), particularly in community settings, often due to medications. Effective prevention hinges on identifying high-risk patients, yet existing models for predicting AKI risk in older outpatients are scarce, particularly those incorporating medication variables. We aimed to develop an AKI risk prediction model that included medication-related variables for older outpatients.

METHODS

We constructed a cohort of 2,272,257 outpatients aged ≥65 years using a national claims database. This cohort was split into a development (70%) and validation (30%) groups. Our primary goal was to identify newly diagnosed AKI within one month of cohort entry in an outpatient context. We screened 170 variables and developed a risk prediction model using logistic regression.

RESULTS

The final model integrated 12 variables: 2 demographic, 4 comorbid, and 6 medication-related. It showed good performance with acceptable calibration. In the validation cohort, the area under the receiver operating characteristic curve value was 0.720 (95% confidence interval, 0.692-0.748). Sensitivity and specificity were 69.9% and 61.9%, respectively. Notably, the model identified high-risk patients as having a 27-fold increased AKI risk compared with low-risk individuals.

CONCLUSION

We have developed a new AKI risk prediction model for older outpatients, incorporating critical medication-related variables with good discrimination. This tool may be useful in identifying and targeting patients who may require interventions to prevent AKI in an outpatient setting.

Dysregulation of ferroptosis may participate in the mitigating effect of CoCl2 on contrast-induced nephropathy

BACKGROUND

Contrast agents can directly or indirectly induce renal tubular ischemia and hypoxic damage. Given that cobalt chloride (CoCl2) can protect renal tubules, the protective effect and potential mechanism of action of CoCl2 on contrast-induced nephropathy (CIN) warrant investigation.

METHODS

A CIN mouse model was established to determine the protective effect of CoCl2 on renal injury in vivo. Then, TMT-based proteomics was performed to determine the differentially expressed proteins (DEPs), following which, enrichment analyses of gene ontology and the KEGG pathway were performed. In vitro, a CIN model was constructed with renal tubular epithelial cells (HK-2) to determine the effect of CoCl2 on potential targets and the role of the key protein identified from the in vivo experiments.

RESULTS

CoCl2 treatment decreased the levels of BUN and serum creatinine (sCr), while increasing the levels of urea and creatinine (Cr) in the urine of mice after CIN injury. Damage to the renal tubules in the CoCl2 treatment group was significantly less than in the CIN model group. We identified 79 DEPs after treating the in vivo model with CoCl2, and frequently observed ferroptosis-related GO and KEGG pathway terms. Of these, Hp (haptoglobin) was selected and found to have a strong renoprotective effect, even though its expression level in kidney tissue decreased after CoCl2 treatment. In HK-2 cells, overexpression of Hp reduced the ferroptosis caused by erastin, while knocking down Hp negated the attenuation effect of CoCl2 on HK-2 cell ferroptosis.

CONCLUSION

CoCl2 attenuated kidney damage in the CIN model, and this effect was associated with the decrease in ferroptosis mediated by Hp.

JQ1 attenuates contrast-induced acute kidney injury through the upregulation of autophagy and inhibition of inflammation

PURPOSE

Contrast-induced acute kidney injury (CI-AKI) is the third most common cause of hospital-acquired AKI. However, there is a paucity of efficacious interventions for the management of CI-AKI. Here, we aim to investigate the effects of JQ1 in CI-AKI and provide theoretical data and a  foundation for  novel ideas for the clinical treatment of CI-AKI.

METHODS

In this study, we performed in vivo and in vitro experiments with mice and HK2 cells injury models respectively. The levels of serum creatinine (Cr) and blood urea nitrogen (BUN) were determined by an automatic analyzer for the measurements of renal function. The viability of HK-2 cells was analyzed using the Cell Counting Kit-8 (CCK-8) kit. Additionally, the kidney changes in the mice were detected using histopathology (H&E) and immunofluorescent staining. The mRNA and protein expressions were assessed using Quantitative real-time PCR and western blot, respectively. Autophagy and apoptosis was analyzed by Transmission electron microscopy (TEM) and TUNEL assay respectively.

RESULTS

The results demonstrated that JQ1 exhibited potency of attenuating CI-AKI in mouse and HK2 cells. JQ1 increased the expression levels of Atg5, Atg7 and LC3B-II, and decreased the protein levels of p62 in the kidney and HK-2 cells. However, the combined use of JQ1 with chloroquine reversed the effects of JQ1. JQ1 also inhibited the inflammatory cells and downregulated the expression of some inflammatory cytokines (IL-6, IL-1β, TNF-α, and IFN-γ).

CONCLUSION

JQ1 protects against CI-AKI by promoting autophagy and inhibiting inflammation and JQ1 may be a promising therapeutic strategy for CI-AKI.

Highly accelerated, Dixon-based non-contrast MR angiography versus high-pitch CT angiography

OBJECTIVES

To compare a novel, non-contrast, flow-independent, 3D isotropic magnetic resonance angiography (MRA) sequence that combines respiration compensation, electrocardiogram (ECG)-triggering, undersampling, and Dixon water-fat separation with an ECG-triggered aortic high-pitch computed tomography angiography (CTA) of the aorta.

MATERIALS AND METHODS

Twenty-five patients with recent CTA were scheduled for non-contrast MRA on a 3 T MRI. Aortic diameters and cross-sectional areas were measured on MRA and CTA using semiautomatic measurement tools at 11 aortic levels. Image quality was assessed independently by two radiologists on predefined aortic levels, including myocardium, proximal aortic branches, pulmonary veins and arteries, and the inferior (IVC) and superior vena cava (SVC). Image quality was assessed on a 5-point Likert scale.

RESULTS

All datasets showed diagnostic image quality. Visual grading was similar for MRA and CTA regarding overall image quality (0.71), systemic arterial image quality (p = 0.07-0.91) and pulmonary artery image quality (p = 0.05). Both readers favored MRA for SVC and IVC, while CTA was preferred for pulmonary veins (all p < 0.05). No significant difference was observed in aortic diameters or cross-sectional areas between native MRA and contrast-enhanced CTA (p = 0.08-0.94).

CONCLUSION

The proposed non-contrast MRA enables robust imaging of the aorta, its proximal branches and the pulmonary arteries and great veins with image quality and aortic diameters and cross-sectional areas comparable to that of CTA. Moreover, this technique represents a suitable free-breathing alternative, without the use of contrast agents or ionizing radiation. Therefore, it is especially suitable for patients requiring repetitive imaging.

Effects of Low-Osmolar Contrast Media on Long-Term Renal Impairment After Coronary Angiography: Iohexol Versus Iopromide

To investigate the long-term effects of 2 commonly used low-osmolar contrast media, iohexol and iopromide, on renal function and survival in patients who underwent coronary angiography. A total of 14,141 cardiology patients from 2006 to 2013 were recruited, of whom 1,793 patients (679 patients on iohexol and 1,114 on iopromide) were evaluated for long-term renal impairment and 5,410 patients (1,679 patients on iohexol and 3,731 on iopromide) were admitted for survival analyses spanning as long as 15 years. Univariate and multivariate logistic regression were used to explore the risk factors for long-term renal impairment. Cox proportional hazard regression was used to investigate the risk factors affecting survival. Propensity score matching and inverse probability of treatment weighting were applied to balance the baseline clinical characteristics. Patients receiving iohexol demonstrated a greater occurrence of renal impairment compared with those who received iopromide. Such difference remained consistent both before and after propensity score matching or inverse probability of treatment weighting, with a statistical significance of p <0.05. Among clinical variables, receiving contrast-enhanced contrast tomography/magnetic resonance imaging during follow-up, antihypertensive medication usage, presence of proteinuria, and anemia were identified as risk factors for long-term renal impairment (p = 0.041, 0.049, 0.006, and 0.029, respectively). During survival analyses, the difference was insignificant after propensity score matching and inverse probability of treatment weighting. In conclusion, administration of iohexol was more likely to induce long-term renal impairment than iopromide, particularly among patients diagnosed with anemia and proteinuria and those taking antihypertensive medication and with additional contrast exposure. The all-cause mortality, however, showed no significant difference between iohexol and iopromide administration.

The intellectual base and global trends in contrast-induced acute kidney injury: a bibliometric analysis

Contrast-induced acute kidney injury (CI-AKI) has become the third leading cause of hospital-acquired kidney injury. A comprehensive analysis of the current state of research in the field of CI-AKI will help to reveal trends and hot topics in the field. To date, there are no published bibliometric analyses related to CI-AKI studies. Here, we analyze the relevant literature since the emergence of the concept and provide valuable insights. The literature was collected from the Web of Science Core Collection. The data were analyzed visually using CiteSpace and VOSviewer software. We collected a total of 4775 papers, with the United States and Guangdong Acad Med Sci as the major publishing powers in terms of country/region and institution. J AM COLL CARDIOL was the journal with the most published and cocited articles. Cluster analysis showed that clinical trials are the current research hotspot. The areas of risk assessment, prevention strategies, risk factors, and vascular lesions have been popular in recent years. Research on the mechanism of injury in CI-AKI will be the focus of future research, which will be crucial to reduce the clinical incidence of CI-AKI. In summary, this study provides a comprehensive analysis of the development process in the field of CI-AKI and discusses future research directions based on the analysis of objective data from many studies on CI-AKI.

Photon-counting CT for diagnosis of acute pulmonary embolism: potential for contrast medium and radiation dose reduction

OBJECTIVE

To evaluate the image quality of an ultra-low contrast medium and radiation dose CT pulmonary angiography (CTPA) protocol for the diagnosis of acute pulmonary embolism using a clinical photon-counting detector (PCD) CT system and compare its performance to a dual-energy-(DE)-CTPA protocol on a conventional energy-integrating detector (EID) CT system.

METHODS

Sixty-four patients either underwent CTPA with the novel scan protocol on the PCD-CT scanner (32 patients, 25 mL, CTDIvol 2.5 mGy·cm) or conventional DE-CTPA on a third-generation dual-source EID-CT (32 patients, 50 mL, CTDIvol 5.1 mGy·cm). Pulmonary artery CT attenuation, signal-to-noise ratio, and contrast-to-noise-ratio were assessed as objective criteria of image quality, while subjective ratings of four radiologists were compared at 60 keV using virtual monoenergetic imaging and polychromatic standard reconstructions. Interrater reliability was determined by means of the intraclass correlation coefficient (ICC). Effective dose was compared between patient cohorts.

RESULTS

Subjective image quality was deemed superior by all four reviewers for 60-keV PCD scans (excellent or good ratings in 93.8% of PCD vs. 84.4% of 60 keV EID scans, ICC = 0.72). No examinations on either system were considered "non-diagnostic." Objective image quality parameters were significantly higher in the EID group (mostly p < 0.001), both in the polychromatic reconstructions and at 60 keV. The ED (1.4 vs. 3.3 mSv) was significantly lower in the PCD cohort (p < 0.001).

CONCLUSIONS

PCD-CTPA allows for considerable reduction of contrast medium and radiation dose in the diagnosis of acute pulmonary embolism, while maintaining good to excellent image quality compared to conventional EID-CTPA.

CLINICAL RELEVANCE STATEMENT

Clinical PCD-CT allows for spectral assessment of pulmonary vasculature with high scan speed, which is beneficial in patients with suspected pulmonary embolism, frequently presenting with dyspnea. Simultaneously PCD-CT enables substantial reduction of contrast medium and radiation dose.

KEY POINTS

• The clinical photon-counting detector CT scanner used in this study allows for high-pitch multi-energy acquisitions. • Photon-counting computed tomography allows for considerable reduction of contrast medium and radiation dose in the diagnosis of acute pulmonary embolism. • Subjective image quality was rated best for 60-keV photon-counting scans.

Thyroid dysfunction associated with iodine-contrast media: A real-world pharmacovigilance study based on the FDA adverse event reporting system

Objective

To comprehensively analyze characteristics of thyroid dysfunction associated with iodine contrast media (ICM) based on data from the FDA adverse event reporting system (FAERS).

Methods

Disproportionate analysis was employed to identify signals of thyroid dysfunction caused by ICM, and descriptive analysis was performed to examine the clinical characteristics of reported cases involving ICM-related thyroid dysfunctions.

Results

A total of 83 adverse event reports were identified, documenting thyroid dysfunctions associated with ICM agents. Treatment with ICM was significantly associated with higher reporting of hypothyroidism ([ROR] = 2.21, 95 % CI: 1.59-3.08; IC025 = 0.58) and hyperthyroidism (ROR = 3.49, 95 % CI: 2.37-5.13; IC025 = 1.14). Among the six ICM agents investigated, iodixanol demonstrated the highest signal strength in both hypothyroidism (ROR = 9.47) and hyperthyroidism (ROR = 5.44). Hypothyroidism and hyperthyroidism almost occurred in the first 30 days after ICM administration (76.9 % and 70 % of patients, respectively). Furthermore, the proportion of severe outcomes in hyperthyroidism was significantly higher than that in hypothyroidism (12/26 vs. 2/35, P = 0.009).

Conclusion

The present study highlights the varying risks of thyroid dysfunction associated with different ICM agents, with iodixanol exhibiting the highest signal intensity. Hypothyroidism and hyperthyroidism associated with ICM generally manifest within the first month following administration. Consequently, monitoring of thyroid function during this period is strongly recommended for ICM agents presenting higher risk profiles.

Incidences of and risk factors for clinical and subclinical contrast-associated acute kidney injury in patients who underwent neuroendovascular surgery

BACKGROUND

Contrast-associated acute kidney injury (CA-AKI) can develop after intravascular administration of iodinated contrast media. Neutrophil gelatinase-associated lipocalin (NGAL) is an early marker for AKI that helps to detect subclinical CA-AKI. We investigated the incidence of and risk factors for clinical and subclinical CA-AKI in patients who underwent neuroendovascular surgery.

METHODS

We retrospectively investigated 228 patients who underwent neuroendovascular surgery in 2020. Changes in serum creatinine and urine output were used to detect clinical CA-AKI. Urine NGAL concentration was used to detect subclinical CA-AKI in 67 out of 228 patients.

RESULTS

In 228 patients, serum creatinine, hemoglobin, hematocrit, total protein, and blood urea nitrogen (BUN) decreased significantly (p < 0.001) after surgery. However, serum creatinine decreased less significantly (p < 0.05) than hemoglobin, hematocrit, total protein, and BUN on postoperative Day 3. Two patients out of 228 developed clinical CA-AKI, and seven patients out of 67 with urine NGAL measurements developed subclinical CA-AKI. Multivariate regression analysis revealed that diabetes mellitus and carotid artery stenosis were significantly (p < 0.05) associated with the development of clinical and/or subclinical CA-AKI.

CONCLUSION

There was a large difference between the incidences of clinical CA-AKI (0.88%) and subclinical CA-AKI (10.4%). The difference might have primarily resulted from the different sensitivities between serum creatinine and urine NGAL and possibly from underestimation of the incidence of clinical AKI due to a postoperative decrease in serum creatinine caused by hemodilution. In addition to diabetes mellitus, carotid artery stenosis could also be a risk factor for CA-AKI.

Predictive value of hemoglobin-to-red blood cell distribution width ratio for contrast-induced nephropathy after emergency percutaneous coronary intervention

BACKGROUND

Although the relationship of either hemoglobin or red blood cell distribution width (RDW) with contrast-induced nephropathy (CIN) has been reported individually. To date, no studies have evaluated the predictive value of hemoglobin-to-red blood cell distribution width ratio (HRR) for CIN.

METHODS

A total of 1658 elderly patients with ST-segment elevation myocardial infarction (STEMI) undergoing emergency percutaneous coronary intervention (PCI) were retrospectively screened. Preoperative complete blood count was collected and the HRR was calculated as the ratio of hemoglobin to RDW. CIN was defined as an absolute ≥0.5 mg/dL (44.2 μmol/L) or a relative ≥25% increase in creatinine level at 72 h after contrast administration. Univariate and multivariate regression analysis were conducted to determine the effective predictors for CIN. The ROC curve analysis was plotted to determine the optimal cutoff value for HRR in predicting CIN.

RESULTS

The overall incidence of CIN was 8.38%. The HRR was significantly lower in the CIN group compared with the non-CIN group (0.87 ± 0.15 vs 1.24 ± 0.23, p < 0.001). After multivariate regression analysis was performed, HRR was noted to be an effective predictor for the development of CIN (OR 1.617, 95% CI 1.439-2.706, p = 0.014), along with age, creatinine, eGFR, hs-CRP and contrast volume. An optimal cutoff value of 0.94 or lower for HRR was identified with 82.4% sensitivity and 63.5% specificity to predict CIN.

CONCLUSION

Lower HRR on admission was an effective predictor for CIN in elderly patients with STEMI undergoing emergency PCI. HRR may be a convenient, economical and reliable biomarker for risk stratification.

Effect of iodinated contrast media on peripheral blood mononuclear cells in terms of cell viability, cell cycle and oxidative stress in an in vitro system

Iodine contrast agents are essential for diagnostic purposes in radiology and have significant medical benefits. However, they pose a risk of causing allergic reactions or adverse cellular effects. In this study, we examine the in vitro effects of iodine contrast agents (Iopamiro 370, Ultravist 370, Visipaque 320, and Optiray 350) on cellular functions of human peripheral blood mononuclear. The findings reveal that a concentration of 50 mgI/ml of iodine contrast agents causes a 50% reduction in cell viability, but lower concentrations of 2.5, 5.0, and 10.0 mgI/ml do not affect the cell cycle. Furthermore, the contrast agents decrease oxidative stress levels in cells. In conclusion, this study demonstrates that iodine contrast agents can be used safely in appropriate concentrations for diagnostic purposes without affecting the cell cycle and preventing oxidative stress on normal cells. The insights gained from this study could aid in the development of diagnostic contrast agents in the future of medicine.

Dynamic Changes in the Renal Function of Acute Myocardial Infarction Patients with Reduced eGFR After Emergency Percutaneous Coronary Intervention

Renal dysfunction greatly influences decision-making for emergency percutaneous coronary intervention (PCI) in patients with acute myocardial infarction (AMI). This observational study investigated renal function changes and risk factors for renal injury in patients with AMI with reduced estimated glomerular filtration rate (eGFR) who underwent emergency PCI. The study included 85 patients with AMI with decreased eGFR who underwent emergency PCI, categorized into stage 2, 3, and 4 chronic kidney disease groups. Baseline data, laboratory indicators, coronary characteristics, and serum creatinine concentration were monitored at multiple time points. Renal injury was defined using two criteria: an increase in serum creatinine level by 0.3 mg/dL or a 50% increase from baseline. During the 1-year follow-up, renal injury incidence varied from 1.18% to 15.29%. The pattern showed an increasing trend in the 1st week after PCI, peaking at 1 week, followed by a decrease at 3 months, and another increase at one year. Low basal eGFR, high contrast agent dosage, and diabetes were associated with renal injury according to logistic regression analysis. The eGFR cutoff value of 35.475 mL/minute·1.73 m2 had a sensitivity of 83.05% and specificity of 57.69% for predicting renal injury based on receiver operating characteristic curve analysis. In summary, patients with AMI with basal eGFR lower than 35.475 mL/minute·1.73 m2 have a higher risk of renal injury after PCI. These findings emphasize the importance of assessing renal function and considering associated risk factors when deciding on emergency PCI for AMI with reduced eGFR.

Electronic alert outpatient protocol improves the quality of care for the risk of postcontrast acute kidney injury following computed tomography

BACKGROUND

Prevention and diagnosis of postcontrast acute kidney injury (AKI) after contrast-enhanced computed tomography is burdensome in outpatient department. We investigated whether an electronic alert system could improve prevention and diagnosis of postcontrast AKI.

METHODS

In March 2018, we launched an electronic alert system that automatically identifies patients with a baseline estimated glomerular filtration rate of <45 mL/min/1.73 m2, provides a prescription of fluid regimen, and recommends a follow-up for serum creatinine measurement. Participants prescribed contrast-enhanced computed tomography at outpatient department before and after the launch of the system were categorized as historical and alert group, respectively. Propensity for the surveillance of postcontrast AKI was compared using logistic regression. Risks of AKI, admission, mortality, and renal replacement therapy were analyzed.

RESULTS

The historical and alert groups included 289 and 309 participants, respectively. The alert group was more likely to be men and take diuretics. The most frequent volume of prophylactic fluid in historical and alert group was 1,000 and 750 mL, respectively. Follow-up for AKI was more common in the alert group (adjusted odds ratio, 6.00; p < 0.001). Among them, incidence of postcontrast AKI was not statistically different. The two groups did not differ in risks of admission, mortality, or renal replacement therapy.

CONCLUSION

The electronic alert system could assist in the detection of high-risk patients, prevention with reduced fluid volume, and proper diagnosis of postcontrast AKI, while limiting the prescribing clinicians' burden. Whether the system can improve long-term outcomes remains unclear.

Delivery of recombinant sestrin2 ameliorates oxidative stress, mitochondrial damage and renal dysfunction in contrast-induced acute kidney injury

Although the use of iodinated contrast agents is sometimes unavoidable for accurate diagnosis, contrast-induced acute kidney injury (CI-AKI) is a possible complication of its administration. The pathogenesis of CI-AKI has not been fully elucidated, but oxidative stress is thought to be a major factor. Sestrin2 plays an important role in cellular and mitochondrial homeostasis by regulating oxidative stress. In this study, we aimed to investigate whether recombinant adenovirus containing sestrin2 (RS) can attenuate CI-AKI by reducing oxidative stress in a CI-AKI mice model. Our results showed that RS decreases oxidative stress, pro-inflammatory cytokines (TNF-α, IL-1α, IL-1β and IL-6) and apoptosis (Bax/Bcl2 and cleaved caspase-3) in the CI-AKI model. Additionally, RS alleviated mitochondrial damage, as evidenced by morphological changes, are restored ATP synthesis. Furthermore, RS administration resulted in a decrease in mitochondrial fission marker (Drp1) that was increased in the CI-AKI model, while the mitochondrial fusion marker (Mfn2) increased, indicating a restoration of mitochondrial dynamics. Decreased relative blood volume, as evaluated on computed tomography (CT), significantly increased compared to the CI-AKI group after RS administration. Finally, renal injury markers such as Kim-1, Ngal, IL-18 also decreased and kidney function was preserved with RS. These results suggested that RS can mitigate the deterioration of renal function in CI-AKI model.

An Analysis of the Prevalence and Risk Factors of Contrast-Associated Acute Kidney Injury in Patients With Diabetic Foot Ulcer

The occurrence of contrast-associated acute kidney injury (CA-AKI) is influenced by both patient-related and contrast-related factors. More specifically, CA-AKI has been linked to renal dysfunction, diabetes mellitus (DM), and atherosclerotic cardiovascular diseases (ASCVD). We hypothesized that the prevalence of CA-AKI was high in patients with diabetic foot ulcers (DFU) because they frequently have several ASCVD risk factors and additional comorbid conditions (including ASCVD). We retrospectively examined the medical records of 208 type 2 diabetic patients who were hospitalized for DFU. These patients were divided into two groups: group 1 included 107 patients who underwent contrast-enhanced computed tomographic angiography (CTA); group 2 (control group) included 101 patients who did not receive contrast media. Following CTA, 13 (12.1%) patients developed CA-AKI in group 1, while 3 (3.0%) patients in group 2 had serum creatinine elevations consistent with AKI (P = 0.013). The following risk factors for CA-AKI were identified: longer history of DM, higher baseline serum creatinine, congestive heart failure, Wagner stage 4 and 5 DFUs, peripheral artery disease, older age, and lower hemoglobin values. CA-AKI is a common complication after CTA in patients with DFU. To reduce the risk of CA-AKI in these patients, associated risk factors and preventive measures should be considered.

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.

De Ritis Ratio is Associated with Contrast-Associated Acute Kidney Injury Prediction and Long-Term Clinical Outcomes in Patients Undergoing Emergency Percutaneous Coronary Intervention

Contrast-associated acute kidney injury (CA-AKI) is a familiar complication following percutaneous coronary intervention (PCI). The present study evaluated the predictive value of the De Ritis ratio for CA-AKI and its association with long-term clinical outcomes in patients undergoing emergency PCI. Overall, 546 patients were included in this study. The De Ritis ratio was calculated by aspartate aminotransferase/alanine aminotransferase activity. The De Ritis ratios in the CA-AKI patients were significantly higher than the non-CA-AKI patients [3.74 (2.32, 4.90) vs 1.61 (1.02, 2.53); P < .001]. The De Ritis ratio was an independent risk factor for CA-AKI [odds ratio, 2.243; 95% confidence interval (CI), 1.823-2.759; P < .001]. The area under the ROC curve was .813 (95% CI, .763-.862; P < .001), and the sensitivity and specificity were 67.0% and 82.4%, respectively, when the optimum cut-off value was 2.97. Furthermore, patients in the high De Ritis ratio group (≥1.76) had a significantly greater incidence of primary endpoints [26.7% (73/273) vs 13.2% (36/273); P < .001], and the high De Ritis ratio was an independent predictor for primary endpoints (hazard ratio, 1.888, 95% CI, 1.235-2.887; P = .003). In conclusion, the De Ritis Ratio is associated with CA-AKI prediction and long-term clinical outcomes in patients undergoing emergency PCI.

Different hydration methods for the prevention of contrast-induced nephropathy in patients with elective percutaneous coronary intervention: a retrospective study

BACKGROUND

Hydration is currently the main measure to prevent contrast-induced nephropathy (CIN). We aimed to compare the preventive effect of preprocedure and postprocedure hydration on CIN in patients with coronary heart disease undergoing elective percutaneous coronary intervention (PCI).

METHODS

A retrospective study included 198 cases of postprocedure hydration and 396 cases of preprocedure hydration using propensity score matching. The incidence of CIN 48 h after PCI and adverse events within 30 days after contrast media exposure were compared between the two groups. Logistic regression analysis was used to analyse the risk factors for CIN.

RESULTS

The incidence of CIN in the postprocedure hydration group was 3.54%, while that in the preprocedure hydration group was 4.8%. There was no significant difference between the two groups (p = 0.478). Multivariate logistic regression analysis showed that diabetes mellitus, baseline BNP and cystatin C levels, and contrast agent dosage were independent risk factors for CIN. There was no significant difference in the incidence of major adverse events between the two groups (3.03% vs. 2.02%, p = 0.830).

CONCLUSIONS

Postprocedure hydration is equally effective compared to preoperative hydration in the prevention of CIN in patients with coronary heart disease undergoing elective PCI.

Terbium-doped carbon dots (Tb-CDs) as a novel contrast agent for efficient X-ray attenuation

Metal-doped carbon dots have attracted considerable attention in nanomedicine over the last decade owing to their high biocompatibility and great potential for bioimaging, photothermal therapy, and photodynamic therapy. In this study, we prepared, and for the first time, examined terbium-doped CDs (Tb-CDs) as a novel contrast agent for computed tomography. A detailed physicochemical analysis revealed that the prepared Tb-CDs have small sizes (∼2-3 nm), contain relatively high terbium concentration (∼13.3 wt%), and exhibit excellent aqueous colloidal stability. Furthermore, preliminary cell viability and CT measurements suggested that Tb-CDs exhibit negligible cytotoxicity toward L-929 cells and demonstrate high X-ray absorption performance (∼48.2 ± 3.9 HU L g^-1). Based on these findings, the prepared Tb-CDs could serve as a promising contrast agent for efficient X-ray attenuation.

Cardiac Imaging Biomarkers in Chronic Kidney Disease

Uremic cardiomyopathy (UC), the peculiar cardiac remodeling secondary to the systemic effects of renal dysfunction, is characterized by left ventricular (LV) diffuse fibrosis with hypertrophy (LVH) and stiffness and the development of heart failure and increased rates of cardiovascular mortality. Several imaging modalities can be used to obtain a non-invasive assessment of UC by different imaging biomarkers, which is the focus of the present review. Echocardiography has been largely employed in recent decades, especially for the determination of LVH by 2-dimensional imaging and diastolic dysfunction by pulsed-wave and tissue Doppler, where it retains a robust prognostic value; more recent techniques include parametric assessment of cardiac deformation by speckle tracking echocardiography and the use of 3D-imaging. Cardiac magnetic resonance (CMR) imaging allows a more accurate assessment of cardiac dimensions, including the right heart, and deformation by feature-tracking imaging; however, the most evident added value of CMR remains tissue characterization. T1 mapping demonstrated diffuse fibrosis in CKD patients, increasing with the worsening of renal disease and evident even in early stages of the disease, with few, but emerging, prognostic data. Some studies using T2 mapping highlighted the presence of subtle, diffuse myocardial edema. Finally, computed tomography, though rarely used to specifically assess UC, might provide incidental findings carrying prognostic relevance, including information on cardiac and vascular calcification. In summary, non-invasive cardiovascular imaging provides a wealth of imaging biomarkers for the characterization and risk-stratification of UC; integrating results from different imaging techniques can aid a better understanding of the physiopathology of UC and improve the clinical management of patients with CKD.

Oral Sodium Chloride in the Prevention of Contrast-Associated Acute Kidney Injury in Elderly Outpatients: The PNIC-Na Randomized Non-Inferiority Trial

OBJECTIVE

We aimed to test the non-inferiority of oral versus intravenous hydration in the incidence of contrast-associated acute kidney injury (CA-AKI) in elderly outpatients undergoing a contrast-enhanced computed tomography (CE-CT) scan.

METHODS

PNIC-Na (NCT03476460) is a phase-2, single-center, randomized, open-label, non-inferiority trial. We included outpatients undergoing a CE-CT scan, >65 years having at least one risk factor for CA-AKI, such as diabetes, heart failure, or an estimated glomerular filtration rate (eGFR) of 30-59 mL/min/1.73 m². Participants were randomized (1:1) to oral sodium-chloride capsules or intravenous hydration. The primary outcome was an increase in serum creatinine >0.3 mg/dL or a reduction in eGFR >25% within 48 h. The non-inferiority margin was set at 5%.

RESULTS

A total of 271 subjects (mean age 74 years, 66% male) were randomized, and 252 were considered for the main analysis (per-protocol). A total of 123 received oral hydration and 129 intravenous. CA-AKI occurred in 9 (3.6%) of 252 patients and 5/123 (4.1%) in the oral-hydration group vs. 4/129 (3.1%) in the intravenous-hydration group. The absolute difference between the groups was 1.0% (95% CI -4.8% to 7.0%), and the upper limit of the 95% CI exceeded the pre-established non-inferiority margin. No major safety concerns were observed.

CONCLUSION

The incidence of CA-AKI was lower than expected. Although both regimens showed similar incidences of CA-AKI, the non-inferiority was not shown.

Potential therapeutic effects of Chinese meteria medica in mitigating drug-induced acute kidney injury

Drug-induced acute kidney injury (DI-AKI) is one of the leading causes of kidney injury, is associated with high mortality and morbidity, and limits the clinical use of certain therapeutic or diagnostic agents, such as antineoplastic drugs, antibiotics, immunosuppressants, non-steroidal anti-inflammatory drugs, and contrast media. In recent years, numerous studies have shown that many Chinese meteria medica, metabolites derived from botanical drugs, and Chinese medicinal formulas confer protective effects against DI-AKI by targeting a variety of cellular or molecular mechanisms, such as oxidative stress, inflammatory, cell necrosis, apoptosis, and autophagy. This review summarizes the research status of common DI-AKI with Chinese meteria medica interventions, including cisplatin, gentamicin, contrast agents, methotrexate, and acetaminophen. At the same time, this review introduces the metabolites with application prospects represented by ginseng saponins, tetramethylpyrazine, panax notoginseng saponins, and curcumin. Overall, this review provides a reference for the development of promising nephroprotectants.

A Synopsis of Current Theories on Drug-Induced Nephrotoxicity

The overriding goal of the treatment of patients is its effectiveness and safety. However, all medications currently being used also exert some adverse pharmaceutical reactions, which may be regarded as an unintended but inevitable cost of pharmacotherapy. The kidney, as the main organ that eliminates xenobiotics, is an organ especially predisposed and vulnerable to the toxic effects of drugs and their metabolites during their excretion from the body. Moreover, some drugs (e.g., aminoglycosides, cyclosporin A, cisplatin, amphotericin B, and others) have a "preferential" nephrotoxicity potential, and their use is associated with an increased risk of kidney damage. Drug nephrotoxicity is, therefore, both a significant problem and a complication of pharmacotherapy. It should be noted that, currently, there is no generally recognized definition of drug-induced nephrotoxicity and no clear criteria for its diagnosis. This review briefly describes the epidemiology and diagnosis of drug-induced nephrotoxicity and characterizes its pathomechanisms, including immunological and inflammatory disturbances, altered kidney blood flow, tubulointerstitial injury, increased lithogenesis-crystal nephropathy, rhabdomyolysis, and thrombotic microangiopathy. The study also lists the basic drugs with nephrotoxicity potential and provides a short overview of the preventive methods for reducing the risk of drug-related kidney damage developing.

CT renal arteriography as a novel imaging guidance for the percutaneous ablation of small renal tumors

PURPOSE

To report procedural data and outcomes of a novel image guidance technique, CT renal arteriography (CTRA), performed to target and ablate small intraparenchymal renal tumors.

MATERIALS AND METHODS

We retrospectively analyzed data of 2 patients undergoing CTRA-guided ablation for 3 renal intraparenchymal tumors, from February to March 2023. We previously evaluated tumor visibility with US/CEUS, and in all cases conspicuity was poor, whereas contrast-enhanced CT (CECT) clearly depicted all hypervascular nodules. Our primary endpoint was CTRA-guidance feasibility for renal ablation, defined as the precise probe deployment inside the target tumor. The secondary endpoint was CTRA-guided ablation technical success, intended as the inclusion of the whole tumor inside the necrotic volume, with 5 mm safety margins. RENAL scores, complications, procedural time, dose length product (DLP), serum creatinine variation and hospital stay length were also recorded.

RESULTS

A confident deployment of the probe tip inside the nodule was accomplished in all 3 cases, with a 100% of correct targeting. We observed immediate technical success after all 3 ablations. The 3 nodules had a RENAL score <7 points, and we encountered no complications due to line placement or ablation. The average time from preablative to postablative CTRA was 54 min (50-58min), with a DLP of 3632mGy*cm (2807-4458mGy*cm). Serum creatinine didn't show a significant variation after the procedures; both patients were hospitalized for 2 days.

CONCLUSION

Preliminary data showed that CTRA-guidance might provide unique advantages over conventional CECT-guidance to assist the ablation of small renal intraparenchymal tumor not visualized on US/CEUS.

Contrast-induced acute kidney injury and its contemporary prevention

The complexity and application range of interventional and diagnostic procedures using contrast media (CM) have recently increased. This allows more patients to undergo procedures that involve CM administration. However, the intrinsic CM toxicity leads to the risk of contrast-induced acute kidney injury (CI-AKI). At present, effective therapy of CI-AKI is rather limited. Effective prevention of CI-AKI therefore becomes crucially important. This review presents an in-depth discussion of CI-AKI incidence, pathogenesis, risk prediction, current preventive strategies, and novel treatment possibilities. The review also discusses the difference between CI-AKI incidence following intraarterial and intravenous CM administration. Factors contributing to the development of CI-AKI are considered in conjunction with the mechanism of acute kidney damage. The need for ultimate risk estimation and the prediction of CI-AKI is stressed. Possibilities of CI-AKI prevention is evaluated within the spectrum of existing preventive measures aimed at reducing kidney injury. In particular, the review discusses intravenous hydration regimes and pre-treatment with statins and N-acetylcysteine. The review further focuses on emerging alternative imaging technologies, alternative intravascular diagnostic and interventional procedures, and new methods for intravenous hydration guidance; it discusses the applicability of those techniques in complex procedures and their feasibility in current practise. We put emphasis on contemporary interventional cardiology imaging methods, with a brief discussion of CI-AKI in non-vascular and non-cardiologic imaging and interventional studies.

Improving Outcomes in Ventricular Tachycardia Ablation Using Imaging to Identify Arrhythmic Substrates

Ventricular tachycardia (VT) ablation is limited by modest acute and long-term success rates, in part due to the challenges in accurately identifying the arrhythmogenic substrate. The combination of multimodality imaging along with information from electroanatomic mapping allows for a more comprehensive assessment of the arrhythmogenic substrate which facilitates VT ablation, and the use of preprocedural imaging has been shown to improve long-term ablation outcomes. Beyond regional recognition of the arrhythmogenic substrate, advanced imaging techniques can be used to create tailored ablation strategies preprocedurally. This review will focus on how imaging can be used to guide ablation planning and execution with a focus on clinical applications aimed at improving the outcome of VT ablation procedures.

Synthetic Post-Contrast Imaging through Artificial Intelligence: Clinical Applications of Virtual and Augmented Contrast Media

Contrast media are widely diffused in biomedical imaging, due to their relevance in the diagnosis of numerous disorders. However, the risk of adverse reactions, the concern of potential damage to sensitive organs, and the recently described brain deposition of gadolinium salts, limit the use of contrast media in clinical practice. In recent years, the application of artificial intelligence (AI) techniques to biomedical imaging has led to the development of 'virtual' and 'augmented' contrasts. The idea behind these applications is to generate synthetic post-contrast images through AI computational modeling starting from the information available on other images acquired during the same scan. In these AI models, non-contrast images (virtual contrast) or low-dose post-contrast images (augmented contrast) are used as input data to generate synthetic post-contrast images, which are often undistinguishable from the native ones. In this review, we discuss the most recent advances of AI applications to biomedical imaging relative to synthetic contrast media.

Contrast-Induced Acute Kidney Injury: Evidence in Support of Its Existence and a Review of Its Pathogenesis and Management

The role of contrast-induced nephropathy (CIN) remains controversial. Many experts contend that CIN does not exist or is extremely rare. The diagnosis was previously made too frequently and inappropriately in the presence of coexisting and confounding comorbidities and risk factors making it difficult to singularly isolate the etiologic role of intravenous contrast media in acute kidney injury (AKI). It is probable that many patients were denied important diagnostic information from radiocontrast studies for fear of CIN. Recently, a new terminology for CIN was introduced, and the term CIN was replaced by two interrelated new terms: one is contrast-associated acute kidney injury (CA-AKI), and the second one is contrast-induced acute kidney injury (CI-AKI). CA-AKI occurs in association with risk factors or comorbidities, therefore, it is a correlative diagnosis. On the other hand, CI-AKI is a subtype of CA-AKI that results directly from iodinated contrast media. In this review, we present evidence from various studies that argue against CI-AKI and also those that suggest its existence but with much lower frequency. We will also provide the current status of the pathophysiology and management of CA-AKI/CI-AKI.

Advances in cerebral perfusion imaging techniques in acute ischemic stroke

The application of cerebral perfusion imaging has demonstrated significant assessment benefits and an ability to establish an appropriate triage of patients with acute ischemic stroke (AIS) and large artery occlusion (LAO) in the extended time window. Computed tomography perfusion (CTP) and magnetic resonance imaging (MRI) are routinely used to determine the ischemic core, as well as the tissue at risk, to aid in therapeutic decision-making. However, the time required to transport patients to imaging extends the door-to-reperfusion time. C-arm cone-beam CT (CBCT) is a novel tomography technology that combines 2D radiography and 3D CT imaging based on the digital subtraction angiography platform. In comparison with CT or MRI perfusion techniques, CBCT combined with catheterized angiogram or therapy can serve as a "one-stop-shop" for the diagnosis and treatment of AIS, and greatly reduce the door to reperfusion time. Here, we review the current evidence on the efficacy and theoretical basis of CBCT, as well as other perfusion techniques, with the purpose to assist clinicians to establish an effective and repaid workflow for patients with AIS and LAO in clinical practice.

Artificial intelligence in oncologic imaging

Radiology is integral to cancer care. Compared to molecular assays, imaging has its advantages. Imaging as a noninvasive tool can assess the entirety of tumor unbiased by sampling error and is routinely acquired at multiple time points in oncological practice. Imaging data can be digitally post-processed for quantitative assessment. The ever-increasing application of Artificial intelligence (AI) to clinical imaging is challenging radiology to become a discipline with competence in data science, which plays an important role in modern oncology. Beyond streamlining certain clinical tasks, the power of AI lies in its ability to reveal previously undetected or even imperceptible radiographic patterns that may be difficult to ascertain by the human sensory system. Here, we provide a narrative review of the emerging AI applications relevant to the oncological imaging spectrum and elaborate on emerging paradigms and opportunities. We envision that these technical advances will change radiology in the coming years, leading to the optimization of imaging acquisition and discovery of clinically relevant biomarkers for cancer diagnosis, staging, and treatment monitoring. Together, they pave the road for future clinical translation in precision oncology.

Association Between Contrast Volume-to-Creatinine Clearance Ratio and the Risk of Perioperative Myocardial Infarction After Elective Percutaneous Coronary Intervention

Although the use of iodinated contrast for percutaneous coronary intervention (PCI) has known toxicity issues, the association between the contrast volume-to-creatinine clearance (V/CrCl) ratio and perioperative myocardial infarction (PMI) is unclear. The present study is aimed to investigate the predictive value of V/CrCl ratio on the incidence of PMI, and to determine a relatively safe contrast media V/CrCl ratio cut-off value to prevent PMI undergoing elective PCI. The V/CrCl ratio were obtained from 5970 patients undergoing elective PCI for single-vessel lesions. Cardiac troponin I (cTnI) were measured at baseline, 8, 16, and 24 hours after PCI. PMI was defined as postprocedural > 5 × upper limit of normal. Receiver operating characteristic (ROC) curves were performed to identify the optimal sensitivity for the V/CrCl range. Multivariate regression model were used to assess the association between V/CrCl ratios and PMI. Eight hundred and ninety-seven patients (15.0%) developed PMI. There was a significant association between higher V/CrCl ratio and the development of PMI (P < 0.001 for the trend). ROC curve analysis indicated that V/CrCl ratio of 2.05 was a discriminator for PMI (area under the curve = 0.674). After adjusting for other potential risk factors, V/CrCl ratio > 2.05 remained significant associated with PMI (odds ratio, 1.921; 95% confidence interval, 1.311-2.815; P = 0.001). The finding of this study suggests the importance of minimizing the contrast media dose to avoid PMI development. Use of a contrast media dose based on renal function with a V/CrCl value < 2.05 might be valuable in preventing PMI.

Risk of Dementia after Exposure to Contrast Media: A Nationwide, Population-Based Cohort Study

Contrast-medium-associated kidney injury is caused by the infusion of contrast media. Small vessel disease is significantly associated with various diseases, including simultaneous conditions of the kidney and brain, which are highly vulnerable to similar vascular damage and microvascular pathologies. Data to investigate the adverse effect of contrast media on the brain remain extremely lacking. In this study, 11,332,616 NHI enrollees were selected and divided into two groups, exposed and not exposed to a contrast medium during the observation period, from which 1,461,684 pairs were selected for analyses through matching in terms of age, sex, comorbidities, and frequency of outpatient visits during the previous year. In total, 1,461,684 patients exposed to a contrast medium and 1,461,684 controls not exposed to one were enrolled. In multivariable Cox proportional hazard models, patients exposed to a contrast medium had an overall 2.09-fold higher risk of dementia. In multivariable-stratified analyses, the risk of Alzheimer’s disease was remarkably high in younger patients without any underlying comorbidity. This study is the first to discover that exposure to contrast media is significantly associated with the risk of dementia. A four-fold increased risk of vascular dementia was observed after exposure to a contrast medium. Further studies on the influence of exposure to contrast media on the brain are warranted.

Radiographic Contrast Media and the Kidney

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

Biocompatible carbonized iodine-doped dots for contrast-enhanced CT imaging

Background

Computed tomography (CT) imaging has been widely used for the diagnosis and surveillance of diseases. Although CT is attracting attention due to its reasonable price, short scan time, and excellent diagnostic ability, there are severe drawbacks of conventional CT contrast agents, such as low sensitivity, serious toxicity, and complicated synthesis process. Herein, we describe iodine-doped carbon dots (IDC) for enhancing the abilities of CT contrast agents.

Method

IDC was synthesized by one-pot hydrothermal synthesis for 4 h at 180 ℃ and analysis of its structure and size distribution with UV–Vis, XPS, FT-IR, NMR, TEM, and DLS. Furthermore, the CT values of IDC were calculated and compared with those of conventional CT contrast agents (Iohexol), and the in vitro and in vivo toxicities of IDC were determined to prove their safety.

Results

IDC showed improved CT contrast enhancement compared to iohexol. The biocompatibility of the IDC was verified via cytotoxicity tests, hemolysis assays, chemical analysis, and histological analysis. The osmotic pressure of IDC was lower than that of iohexol, resulting in no dilution-induced contrast decrease in plasma.

Conclusion

Based on these results, the remarkable CT contrast enhancement and biocompatibility of IDC can be used as an effective CT contrast agent for the diagnosis of various diseases compared with conventional CT contrast agents.

Supplementary Information

The online version contains supplementary material available at 10.1186/s40824-022-00277-3.

A convenient online desalination tube coupled with mass spectrometry for the direct detection of iodinated contrast media in untreated human spent hemodialysates

Background

Mass spectrometry (MS) analysis using direct infusion of biological fluids is often problematic due to high salts/buffers. Iodinated contrast media (ICM) are frequently used for diagnostic imaging purposes, sometimes inducing acute kidney injury (AKI) in patients with reduced kidney function. Therefore, detection of ICM in spent hemodialysates is important for AKI patients who require urgent continuous hemodiafiltration (CHDF) because it allows noninvasive assessment of the patient’s treatment. In this study, we used a novel desalination tube before MS to inject the sample directly and detect ICM.

Methods

Firstly, spent hemodialysates of one patient were injected directly into the electrospray ionization (ESI) source equipped with a quadrupole time-of-flight mass spectrometer (Q-TOF MS) coupled to an online desalination tube for the detection of ICM and other metabolites. Thereafter, spent hemodialysates of two patients were injected directly into the ESI source equipped with a triple quadrupole mass spectrometer (TQ-MS) connected to that online desalination tube to confirm the detection of ICM.

Results

We detected iohexol (an ICM) from untreated spent hemodialysates of the patient-administered iohexol for computed tomography using Q-TOF MS. Using MRM profile analysis, we have confirmed the detection of ICM in the untreated spent hemodialysates of the patients administered for coronary angiography before starting CHDF. Using the desalination tube, we observed approximately 178 times higher signal intensity and 8 times improved signal-to-noise ratio for ioversol (an ICM) compared to data obtained without the desalination tube. This system was capable of tracking the changes of ioversol in spent hemodialysates of AKI patients by measuring spent hemodialysates.

Conclusion

The online desalination tube coupled with MS showed the capability of detecting iohexol and ioversol in spent hemodialysates without additional sample preparation or chromatographic separation. This approach also demonstrated the capacity to monitor the ioversol changes in patients’ spent hemodialysates.

DyeVert Contrast Reduction System Use in Patients Undergoing Coronary and/or Peripheral Angiography: A Systematic Literature Review and Meta-Analysis

Background

Contrast-associated acute kidney injury (CA-AKI) is an important adverse effect associated with injecting iodinated intra-arterial contrast media (CM) during coronary angiography. The DyeVert™ Contrast Reduction System is a medical device intended to reduce the intra-arterial CM volume (CMV) administered. The aim of this study was to assess DyeVert System clinical effectiveness and safety by implementing a systematic review and meta-analysis of existing evidence.

Methods

Systematic electronic literature searches were conducted in MEDLINE, Embase, the Cochrane Database of Systematic Reviews, ClinicalTrials.gov, and the International Clinical Trials Registry Platform database. Relevant data were extracted from included studies and meta-analyses were performed to synthesize evidence across studies.

Results

The review included 17 eligible studies involving 1,731 DyeVert System cases and 1,387 control cases (without the use of DyeVert). Meta-analyses demonstrated use of the DyeVert System reduced CMV delivered to the patient by 39.27% (95% CI, 36.10-42.48%, P < 0.001), reduced CMV/baseline renal function ratios (Hedges's g, -0.56; 95% CI, -0.70 to -0.42, P < 0.001) and percentage of cases exceeding the maximum CMV threshold (risk difference -0.31, 95% CI, -0.48 to -0.13, P < 0.001) while maintaining adequate image quality in 98% of cases. DyeVert System cases demonstrated lower CA-AKI incidence vs. controls (absolute risk reduction 5.00% (95% CI, 0.40-9.80%; P = 0.03), relative risk 0.60 (95% CI, 0.40-0.90; P = 0.01) with a pooled estimate of the number needed to treat with the DyeVert System to avoid 1 CA-AKI event of 20.

Conclusion

DyeVert System use significantly reduces CMV delivered to the patient, CMV/baseline renal function ratios, and CA-AKI incidence while maintaining image quality. Accordingly, the device may serve as an adjunctive, procedure-based strategy to prevent CA-AKI. Future multi-center studies are needed to further assess effects of minimizing CMV on endpoints such as CA-AKI prevention, incidence of adverse cardiac and renal events, and health care costs.

Mechanism of Abelmoschus manihot L. in the Treatment of Contrast-Induced Nephropathy on the Basis of Network Pharmacology Analysis

Background

Contrast-induced nephropathy (CIN) is increasingly seen in patients receiving contrast medium. Abelmoschus manihot (L.) Medik. (Malvaceae) and its preparations are widely used and effective in the treatment of various chronic kidney diseases and CIN in China. It is supposed to be an important adjuvant therapy for CIN.

Methods

PubMed and CNKI were searched for the main compounds of A. manihot L. The Swiss target prediction platform, OMIM, GeneCards, DisGeNET, and DrugBank databases were mined for information relevant to the prediction of targets that A. manihot L. in the treatment of CIN. Subsequently, STRING database was applied for the construction of the PPI protein interaction network, meanwhile, the core targets were screened. DAVID database was used to perform the GO function and Kegg signal pathway enrichment analysis. AutoDockTools and PYMOAL were used for molecular docking. Vitro experiments were used to verify the effect of TFA, the main active component of A. manihot L., in the intervention of iopromide-induced cells injury.

Results

A total of 17 chemical components and 133 potential targets in A. manihot L. were obtained. The top 15 proteins with higher degree value were selected from the PPI network model, AKT1, PIK3R1, EGFR, SRC,AR, APP, TNF, GAPDH, MMP9, and PTPN1, etc. may be core targets. The enrichment analysis indicated that A. manihot L. was involved in the regulation of PI3K/AKT signaling pathway, FoxO signaling pathway, VEGF signaling pathway, HIF-1, TNF signaling pathway, melanoma, hepatitis B, and other signaling pathways which were mainly associated with the regulation of transcription and apoptosis, protein phosphorylation, inflammatory response, aging, and cell proliferation. Molecular docking indicated that the key components and core targets had a good binding ability. The vitro experiments illustrated that TFA reduces iopromide induced renal tubular cell injury and apoptosis, which may be related to regulating the phosphorylation of AKT.

Conclusion

The study preliminarily revealed the multi-component, multi-target, and multi-pathway synergistic effects of A. manihot L. on CIN, which provide theoretical reference and basis for the study of the pharmacological mechanism of A. manihot L. in the treatment of CIN.

Wellens’ Syndrome from COVID-19 Infection Assessed by Enhanced Transthoracic Coronary Echo Doppler: A Case Report

Wellens’ syndrome (WS) is a preinfarction state caused by a sub-occlusion of the proximal left anterior descending coronary artery (LAD). In this case report, for the first time, we describe how this syndrome can be caused by COVID-19 infection and, most importantly, that it can be assessed bedside by enhanced transthoracic coronary echo Doppler (E-Doppler TTE). This seasoned technique allows blood flow Doppler to be recorded in the coronaries and at the stenosis site but has never been tested in an acute setting. Two weeks after clinical recovery from bronchitis allegedly caused by COVID-19 infection on the basis of epidemiologic criteria (no swab performed during the acute phase but only during recovery, at which time it was negative), our patient developed typical angina for the first time, mainly during effort but also at rest. He was admitted to our tertiary center, where pharyngeal swabs tested positive for COVID-19. A typical EKG finding supporting WS prompted an assessment of the left main coronary artery (LMCA) and the whole LAD blood flow velocity by E-Doppler TTE. Localized high velocity (transtenotic velocity) (100 cm/s) was recorded in the proximal LAD, with the reference velocity being 20 cm/s. This indicated severe stenosis with 90% area narrowing according to the continuity equation, as confirmed by coronary angiography. During follow-up after successful stenting, E-Doppler TTE showed a decrease in the transtenotic acceleration, confirming stent patency and a normal coronary flow reserve (3.2) and illustrating a normal microcirculatory function. Conclusion: COVID infection can trigger a coronary syndrome like WS. E-Doppler TTE, an ionizing radiation-free method, allows safe and rapid bedside management of the syndrome. This new strategy can be pivotal in distinguishing true WS from pseudo-WS. In cases of pseudo-WS, coronary angiography can be avoided. If E-Doppler TTE confirms the stenosis and PCI (percutaneous coronary intervention) is performed, the same method can allow assessment over time of the precise residual stenosis after stenting and verify the microvasculature status by evaluating coronary flow reserve.

The Pathophysiology and the Management of Radiocontrast-Induced Nephropathy

Contrast-induced nephropathy (CIN) is an impairment of renal function that occurs after the administration of an iodinated contrast medium (CM). Kidney dysfunction in CIN is considered transient and reversible in most cases. However, it is the third most common cause of hospital-acquired acute kidney injury and is associated with increased morbidity and mortality, especially in high-risk patients. Diagnostic and interventional procedures that require intravascular CM are being used with increasing frequency, especially among the elderly, who can be particularly susceptible to CIN due to multiple comorbidities. Therefore, identifying the exact mechanisms of CIN and its associated risk factors is crucial not only to provide optimal preventive management for at-risk patients, but also to increase the feasibility of diagnostic and interventional procedure that use CM. CM induces kidney injury by impairing renal hemodynamics and increasing the generation of reactive oxygen species, in addition to direct cytotoxicity. Periprocedural hydration is the most widely accepted preventive strategy to date. Here, we review the latest research results on the pathophysiology and management of CIN.

Enhanced external counterpulsation: A new method to alleviate contrast-induced acute kidney injury

BACKGROUND

Contrast-induced acute kidney injury (CI-AKI) is a common complication after exposure to contrast media. Renal ischaemia occurs in the initial stage of CI-AKI, however, there are very few effective measures to improve renal perfusion.

METHODS

A total of 114 patients with an estimated glomerular filtration rate (eGFR) of 60-89 ml/min/1.73m² were randomly assigned to two groups: enhanced external counterpulsation (EECP) group (N = 57) and control group (N = 57). Two hours after contrast exposure, EECP group received EECP treatment for 1 h while no intervention was performed control group. The primary outcome was the incidence of serum cystatin C concentration to 10% above the baseline concentration at 24 h after contrast administration. The secondary outcomes were the incidence of CI-AKI (defined as an increase in serum creatinine concentration to ≥0.5 mg/dl or by 25% compare to the baseline after contrast exposure), contrast clearance and adverse clinical events.

RESULTS

The primary outcome was observed in 26 patients (6 EECP and 20 control; 11% vs. 35%; P = 0.002). CI-AKI occurred in four patients (0 EECP and 4 control; 0% vs. 7%; P = 0.042). The clearance rate of iopromide in the initial 3 h was significantly different between EECP and control group (59.92 ± 8.84 vs 46.80 ± 9.26 ml/min/1.73 m²; P < 0.001). No adverse clinical events were observed in this study.

CONCLUSIONS

This study demonstrates that EECP increases the contrast clearance and may have an effect in reducing the risk of CI-AKI. The study has been registered in Chinese Clinical Trial Registry (ChiCTR 2,000,039,190).

Exploring the relationship between post-contrast acute kidney injury and different baseline creatinine standards: A retrospective cohort study

OBJECTIVE

According to previous studies, the incidence of post-contrast acute kidney injury(PC-AKI) in diabetic is far higher than that in the general population. Therefore, we explored the relationship between the incidence of PC-AKI and different baseline serum creatinine (SCr) levels, and determined the relationship between PC-AKI and different types of contrast media (CMs), different doses of CM, and different examination methods in this specific population.

MATERIALS AND METHODS

Patients with diabetes in whom CM was used between 2010 and 2020 at our institution were included. Participants were identified according to the following three schemes: Scheme 1 (n=5911), SCr was detected before and within 72 h after using CM; Scheme 2 (n=2385), SCr was detected within 24 h before and within 24-72 h after using CM; and Scheme 3 (n=81), SCr was detected within 24 h before and within 0-24, 24-48, and 48-72 h after using CM. The incidence of PC-AKI with different types of CM, incidence of PC-AKI on digital subtraction angiography (DSA) and enhanced computed tomography (CT), proportion of PC-AKI with different doses of CM, and baseline SCr at different stages of PC-AKI were compared. Multivariate logistic regression analysis was used to explore risk factors for PC-AKI.

RESULTS

A total of 29,081 patients were included in this study. The incidence of PC-AKI in Scheme 3 (22.22%) was higher than those in Schemes 1 (6.19%) and 2 (7.71%). The incidence of PC-AKI on DSA was higher than that on enhanced CT (8.30% vs. 5.80%; P<0.05). The incidence of PC-AKI in the increased-dose CM group was higher than that in the non-increased-dose CM group (7.9% vs. 5.7%; P<0.01). Moreover, there were differences in baseline SCr values at different stages of PC-AKI (P<0.01). Multivariate logistic regression analysis showed that hypertension, chronic kidney disease, heart failure, peripheral vascular disease, metformin, diuretics, and CM dose were risk factors for PC-AKI.

CONCLUSION

The incidence of PC-AKI increased significantly with increasing time requirement and frequency of SCr detection. Moreover, before using CM, we should control the blood pressure and heart failure, stop using metformin and diuretics, and use CMs at the minimum dose to avoid PC-AKI.

Cerebral Venous Thrombosis: A Challenging Diagnosis; A New Nonenhanced Computed Tomography Standardized Semi-Quantitative Method

Cerebral venous sinus thrombosis (CVST) on non-contrast CT (NCCT) is often challenging to detect. We retrospectively selected 41 children and 36 adults with confirmed CVST and two age-matched control groups with comparable initial symptoms. We evaluated NCCT placing four small circular ROIs in standardized regions of the cerebral dural venous system. The mean and maximum HU values were considered from each ROI, and the relative percentage variations were calculated (mean % variation and maximum % variation). We compared the highest measured value to the remaining three HU values through an ad-hoc formula based on the assumption that the thrombosed sinus has higher attenuation compared with the healthy sinuses. Percentage variations were employed to reflect how the attenuation of the thrombosed sinus deviates from the unaffected counterparts. The attenuation of the affected sinus was increased in patients with CVST, and consequently both the mean % and maximum % variations were increased. A mean % variation value of 12.97 and a maximum % variation value of 10.14 were found to be useful to distinguish patients with CVST from healthy subjects, with high sensitivity and specificity. Increased densitometric values were present in the site of venous thrombosis. A systematic, blind evaluation of the brain venous system can assist radiologists in identifying patients who need or do not need further imaging.

Cellular and molecular pathways underlying the nephrotoxicity of gadolinium

Mounting evidence on the short- and long-term adverse effects associated with gadolinium [Gd (III)]-based contrast agents used in magnetic resonance imaging have emerged in the past three decades. Safety issues arise from the release of Gd (III) from chelates and its deposition in tissues, which is exacerbated in patients with renal disease, since the kidney is the major excretion organ of most of these agents. This study aimed at unveiling the cellular and molecular mechanisms of nephrotoxicity of Gd (III), using an in vitro model of human proximal tubular cells (HK-2 cell line). Cell viability declined in a concentration- and time-dependent manner after exposure to GdCl3·6H2O. The estimated inhibitory concentrations (ICs) eliciting 1 to 50% of cell death, after 24 h of exposure, ranged from 3.4 to 340.5 µM. At toxic concentrations, exposure to Gd (III) led to disruption of the oxidative status, mitochondrial dysfunction, cell death by apoptosis, switching to necrosis at higher levels, and autophagic activation. Disturbance of the lipid metabolism was already observed at low-toxicity ICs, with accumulation of lipid droplets, and upregulation of genes related to both lipogenesis and lipolysis. Gd (III)-exposure, even at the subtoxic IC01, increased the expression of modulators of various signaling pathways involved in the development and progression of renal disease, including inflammation, hypoxia and fibrosis. Our results give new insights into the mechanisms underlying the nephrotoxic potential of Gd (III) and highlight the need to further clarify the risks versus benefits of the Gd (III)-based contrast agents currently in use.

Folic Acid Attenuates Contrast-Induced Nephropathy in Patients With Hyperhomocysteinemia Undergoing Coronary Catheterization: A Randomized Controlled Trial

Background: Hyperhomocysteinemia is a risk factor for contrast-induced nephropathy. Folic acid can attenuate such nephropathies in rats. The protective effect of folic acid against contrast-induced nephropathy has not been studied in humans. We aimed to investigate the effect of folic acid on the incidence of contrast-induced nephropathy (CIN) after coronary catheterization in patients with hyperhomocysteinemia.

Methods: This was a single-center, prospective, double-blind, randomized controlled trial (ClinicalTrials.gov, NCT02444013). In total, 412 patients (mean age: 65 ± 12 years, 268 male) with plasma homocysteine ≥15 μM, who underwent coronary arteriography (CAG) or percutaneous coronary intervention (PCI) from May 2015 to August 2018, were enrolled. Patients were randomly assigned to two groups: a treatment group (n = 203), taking 5 mg of folic acid (orally, three times/day) immediately after enrollment and for 72 h after operation, and a control group (n = 209), taking placebo. Contrast-induced nephropathy was defined as an increase in serum creatinine of >25% or 44 μM within 48 or 72 h after contrast medium administration.

Results: In total, 50 (12%) patients developed CIN after 48 h after catheterization, including 16 (8%) in the treatment group and 34 (16%) in the control group (P = 0.009). Meanwhile, 53 (13%) patients developed CIN after 72 h of CAG/PCI, including 18 (9%) in the treatment group and 35 (17%) in the control group (P = 0.017). The incidence of contrast-induced nephropathy in the treatment group was lower than that in the control group (P = 0.017). Logistic regression analysis confirmed that administration of folic acid was a protective factor against contrast-induced nephropathy (RD = 0.0788, 95%CI: 0.0105–0.1469, P = 0.019). We found no serious adverse events associated with folic acid. No death or hemodialysis occurred in either group.

Conclusions: Perioperative administration of folic acid attenuates the incidence of contrast-induced nephropathy after coronary catheterization in patients with hyperhomocysteinemia.

Clinical Trial Registration:ClinicalTrials.gov, identifier [NCT02444013].

Oral hydration as a safe prophylactic measure to prevent post-contrast acute kidney injury in oncologic patients with chronic kidney disease (IIIb) referred for contrast-enhanced computed tomography: subanalysis of the oncological group of the NICIR study

BACKGROUND

T he objective of this study is to evaluate oral hydration compared to intravenous (i.v.) hydration in the prevention of post-contrast acute kidney injury (PC-AKI) in the oncologic subgroup of patients with stage IIIb chronic kidney disease (CKD) included in the NICIR study referred for elective contrast-enhanced computed tomography (CE-CT).

MATERIAL AND METHODS

We performed a retrospective subanalysis of the oncological subgroup (174/228 patients, 74%) from a continuous prospective database of patients included in the recently published non-inferiority NICIR study. Patients received prophylaxis against PC-AKI with either oral hydration (500 mL of water 2 h before and 2000 mL during the 24 h after CE-CT) or i.v. hydration (sodium bicarbonate (166 mmol/L) 3 mL/kg/h starting 1 h before and 1 mL/kg/h during the first hour after CE-CT). The primary outcome was to compare the proportion of PC-AKI in the first 48 to 72 h after CE-CT in the two hydration groups. Secondary outcomes were to compare persistent PC-AKI, the need for haemodialysis, and the occurrence of adverse events related to prophylaxis in each group.

RESULTS

Of 174 patients included in the subanalysis, 82 received oral hydration and 92 received i.v. hydration. There were no significant differences in clinical characteristics or risk factors between the two study arms. Overall the PC-AKI rate was 4.6% (8/174 patients), being 3.7% in the oral hydration arm (3/82 patients) and 5.4% (5/92 patients) in the i.v. hydration arm. The persistent PC-AKI rate was 1.2% (1/82 patients) in the oral hydration arm and 3.3% (3/92 patients) in the i.v. hydration arm. No patient required dialysis during the first month after CE-CT or had adverse effects related to the hydration regime.

CONCLUSION

In oncological patients with stage IIIb CKD referred for elective CE-CT, the rate of PC-AKI in those receiving oral hydration did not significantly differ from that of patients receiving i.v. hydration.

Assessment of 3D Lumbosacral Vascular Anatomy for OLIF51 by Non-Enhanced MRI and CT Medical Image Fusion Technique

Study design: Prospective study. Objective: Medical image fusion can provide information from multiple modalities in a single image. The present study aimed to determine whether three-dimensional (3D) lumbosacral vascular anatomy could be adequately portrayed using a non-enhanced CT–MRI medical image fusion technique. Summary of Background Data: Lateral lumbar interbody fusion has gained popularity for the surgical treatment of adult spinal deformity (ASD). Oblique lumbar interbody fusion at L5–S1 (OLIF51) is receiving considerable attention as a method of creating good L5–S1 lordosis. Access in OLIF51 requires evaluation of the vascular anatomy in the lumbosacral region. Conventional imaging modalities need a contrast medium to describe the vascular anatomy. Methods: Participants comprised 15 patients with ASD or degenerative lumbar disease who underwent corrective surgery at our hospital between January 2020 and June 2021. A 3D vascular image with bony structures was obtained by fusing results from MRI and CT. We processed the merged image and measured the distance between left and right common iliac arteries and veins at two levels: the lower end of the L5 vertebral body (Window A) and the upper end of the S1 vertebral body (Window B). Results: The mean sizes of Window A and Window B were 29.7 ± 10.7 mm and 36.9 ± 10.3 mm, respectively. The mean distance from the bifurcation to the lower end of the L5 vertebra was 23.7 ± 10.9 mm. Coronal deviation of the bifurcation was, from center to left, 12.6 ± 12.3 mm, and the distance from the center of the L5 vertebral body to the bifurcation was 0.79 ± 7.3 mm. Only one case showed a median sacral vein (6.7%). Clinically, we performed OLIF51 in 12 of the 15 cases (80%). Conclusion: Evaluating 3D lumbosacral vascular anatomy using a non-enhanced MRI and CT medical image fusion technique is very useful for OLIF51, particularly for patients in whom the use of contrast medium is contraindicated.

Risk factors of continuous renal replacement therapy following total aortic arch replacement under moderate hypothermia

BACKGROUND

Stanford type A aortic dissection (TAAD) has a sudden onset and high mortality, and emergency total aortic arch replacement (TAAR) is the main treatment option for TAAD. The mortality rate of patients with postoperative acute kidney injury (AKI) combined with continuous renal replacement therapy (CRRT) is remarkable higher than that of patients without AKI. However, incidence of AKI and risk factors for CRRT following TAAR isn't entirely understood.

METHODS

From October 2018 to March 2021, all patients with Stanford type A dissection who underwent total arch replacement surgery under MHCA were enrolled. According to whether CRRT treatment was performed, participants were divided into a CRRT group (n=49) and control group (n=72). Both groups incorporated the brain protection strategy of moderate hypothermia, and the left common carotid artery and the innominate artery were perfused anteriorly. Relevant medical data was collected.

RESULTS

Age, gender, and a history of smoking and drinking were not significantly different between the 2 groups (P>0.1). There were statistical differences between the 2 groups in aortic sinus diameter and Bentall procedure (P≤0.05). Univariate analysis revealed that fresh frozen plasma was a protective factor (P<0.05) and the intraoperative transfusion volume of red blood cells, platelets, fresh frozen plasma, autologous blood used for intraoperative bleeding, aortic sinus diameter, and Bentall procedure were risk factors (P<0.1). Multivariate analysis showed that the Bentall procedure and intraoperative bleeding were risk factors for CRRT (P<0.05), and the aortic sinus diameter and intraoperative transfusion score were also risk factors for CRRT (P<0.05). Receiver operating characteristic (ROC) analysis demonstrated that the model of aortic sinus diameter and intraoperative transfusion score had more significantly different discriminatory powers.

CONCLUSIONS

The Bentall procedure, intraoperative bleeding, aortic sinus diameter, and intraoperative transfusion score were risk factors for postoperative CRRT. The model of aortic sinus diameter and intraoperative transfusion score had more significantly different discriminatory powers.