Contrast-induced acute kidney injury: definition, epidemiology, and outcome

Feasibility of Reduced Iodine Loads for Vascular Assessment Prior to Transcatheter Aortic Valve Implantation (TAVI) Using Spectral Detector CT

Reduced iodine loads for computed tomography (CT)-based vascular assessment prior to transcatheter aortic valve implantation (TAVI) may be feasible in conjunction with a spectral detector CT scanner. This prospective single-center study considered 100 consecutive patients clinically referred for pre-TAVI CT. They were examined on a dual-layer detector CT scanner to obtain an ECG-gated cardiac scan and a non-ECG-gated aortoiliofemoral scan. Either a standard contrast media (SCM) protocol using 80 mL Iohexol 350 mgI/mL (iodine load: 28 gI) or a body-mass-index adjusted reduced contrast media (RCM) protocol using 40-70 mL Iohexol 350 mgI/mL (iodine load: 14-24.5 gI) were employed. Conventional images and virtual monoenergetic images at 40-80 keV were reconstructed. A threshold of 250 HU was set for sufficient attenuation along the arterial access pathway. A qualitative assessment used a five-point Likert scale. Sufficient attenuation in the thoracic aorta was observed for all patients in both groups using conventional images. In the abdominal, iliac, and femoral segments, sufficient attenuation was observed for the majority of patients when using virtual monoenergetic images (SCM: 96-100% of patients, RCM: 88-94%) without statistical difference between both groups. Segments with attenuation measurements below the threshold remained qualitatively assessable as well. Likert scores were 'excellent' for virtual monoenergetic images 50 keV and 55 keV in both groups (RCM: 1.2-1.4, SCM: 1.2-1.3). With diagnostic image quality maintained, it can be concluded that reduced iodine loads of 14-24.5 gI are feasible for pre-TAVI vascular assessment on a spectral detector CT scanner.

Acute and long-term renal effects after iodine contrast media-enhanced computerised tomography in the critically ill-a retrospective bi-centre cohort study

OBJECTIVES

To determine if current clinical use of iodine contrast media (ICM) for computerised tomography (CT) increases the risk of acute kidney injury (AKI) and long-term decline in renal function in patients treated in intensive care.

METHODS

A retrospective bi-centre cohort study was performed with critically ill subjects undergoing either ICM-enhanced or unenhanced CT. AKI was defined and staged based on the Kidney Disease Improve Global Outcome AKI criteria, using both creatinine and urine output criteria. Follow-up plasma creatinine was recorded three to six months after CT to assess any long-term effects of ICM on renal function.

RESULTS

In total, 611 patients were included in the final analysis, median age was 65.0 years (48.0-73.0, quartile 1-quartile 3 (IQR)) and 62.5% were male. Renal replacement therapy was used post-CT in 12.9% and 180-day mortality was 31.2%. Plasma creatinine level on day of CT was 100.0 µmol/L (66.0-166.5, IQR) for non-ICM group and 77.0 µmol/L (59.0-109.0, IQR) for the ICM group. The adjusted odds ratio for developing AKI if the patient received ICM was 1.03 (95% confidence interval 0.64-1.66, p = 0.90). No significant association between ICM and increase in plasma creatinine at long-term follow-up was found, with an adjusted effect size of 2.92 (95% confidence interval - 6.52-12.36, p = 0.543).

CONCLUSIONS

The results of this study do not indicate an increased risk of AKI or long-term decline in renal function when ICM is used for enhanced CT in patients treated at intensive care units.

CLINICAL RELEVANCE STATEMENT

Patients treated in intensive care units had no increased risk of acute kidney injury or persistent decline in renal function after contrast-enhanced CT. This information underlines the need for a proper risk-reward assessment before denying patients a contrast-enhanced CT.

KEY POINTS

• Iodine contrast media is considered a risk factor for the development of acute kidney injury. • Patients receiving iodine contrast media did not have an increased incidence of acute kidney injury or persistent decline in renal function. • A more clearly defined risk of iodine contrast media helps guide clinical decisions whether to perform contrast-enhanced CTs or not.

SGLT-2 inhibitors and prevention of contrast-induced nephropathy in patients with diabetes undergoing coronary angiography and percutaneous coronary interventions: systematic review and meta-analysis

Introduction

SGLT2 inhibitors (SGLT2Is) have demonstrated cardioprotective and nephroprotective effects in patients with and without diabetes. Recent studies suggest that SGLT2Is may reduce the risk of contrast-induced nephropathy (CIN) in patients with diabetes undergoing coronary arteriography (CAG) or percutaneous coronary interventions (PCI). However, the evidence is still inconclusive. We aimed to systematically review the evidence regarding the potential nephroprotective role of SGLT2Is in preventing CIN in this population.

Methods

We searched for studies in six databases published up to September 30, 2023, following a PECO/PICO strategy. Initially, we meta-analyzed five studies, but due to several reasons, mainly methodological concerns, we excluded one RCT. In our final meta-analysis, we included four observational studies.

Results

This meta-analysis comprised 2,572 patients with diabetes undergoing CAG or PCI, 512 patients treated with SGLT2Is, and 289 events of CIN. This is the first meta-analysis demonstrating that SGLT2Is may reduce the risk of developing CIN by up to 63% (RR 0.37; 95% CI 0.24-0.58) in patients with diabetes undergoing CAG or PCI, compared to not using SGLT2Is. Statistical heterogeneity was not significant (I2 = 0%, p = 0.91). We assessed the certainty of the evidence of this systematic review and meta-analysis, according to the GRADE criteria, as moderate.

Conclusion

SGLT2Is significantly reduce the risk of CIN by up to 63% in patients with diabetes undergoing CAG or PCI. Clinical trials are needed; several are already underway, which could confirm our findings and investigate other unresolved issues, such as the optimal dose, type, and duration of SGLT2 inhibitor therapy to prevent CIN.

Systematic Review

PROSPERO, identifier CRD42023412892.

Renal venous density in the arterial phase of contrast-enhanced CT predicts prognosis in septic shock

OBJECTIVE

To evaluate a series of vascular parameters derived from abdominal dual-phase contrast-enhanced CT as predictors of 14-day mortality and AKI within 7 days in septic shock.

METHODS

144 patients with septic shock and 60 negative cases were included. The vascular parameters from CT were measured and calculated, including aortic density in arterial (Dena-A) and venous phase (Dena-V), renal vein density in arterial (Denrv-A) and venous phase (Denrv-V), and renal vein-to-aortic density ratio in arterial (DenRrv/a-A) and venous phase (DenRrv/a-V). The parameters were compared between patients and controls, and between patients with different clinical outcomes, and assessed for predictive value of 14-day mortality and AKI within 7 days.

RESULTS

Patients with septic shock presented significantly lower Denrv-A (p < 0.001) and DenRrv/a-A (p = 0.002) levels than the controls. In the septic shock group, patients who died had significantly lower Denrv-A (p = 0.001) and lower DenRrv/a-A (p < 0.001) than those who survived. Patients who developed AKI had significantly lower Denrv-A (p < 0.001) and DenRrv/a-A (p = 0.011) than those who did not. Multivariate analysis suggested DenRrv/a-A as an independent predictor of 14-day mortality (OR 0.012; 95% confidence interval [CI]:0.002,0.086; p < 0.001) and Denrv-A as an independent predictor of AKI (OR 0.989;95% CI:0.982,0.997; p = 0.006).

CONCLUSION

In septic shock, significant decreases in Denrv-A and DenRrv/a-A were associated with the onset of AKI and predicted higher 14-day mortality.

ADVANCES IN KNOWLEDGE

The renal vein density and renal vein-aortic density ratio in arterial phase of dual-phase contrast-enhanced CT may serve as good predictors of AKI and mortality in septic shock.

Simultaneous stabilization of actin cytoskeleton in multiple nephron-specific cells protects the kidney from diverse injury

Chronic kidney diseases and acute kidney injury are mechanistically distinct kidney diseases. While chronic kidney diseases are associated with podocyte injury, acute kidney injury affects renal tubular epithelial cells. Despite these differences, a cardinal feature of both acute and chronic kidney diseases is dysregulated actin cytoskeleton. We have shown that pharmacological activation of GTPase dynamin ameliorates podocyte injury in murine models of chronic kidney diseases by promoting actin polymerization. Here we establish dynamin's role in modulating stiffness and polarity of renal tubular epithelial cells by crosslinking actin filaments into branched networks. Activation of dynamin's crosslinking capability by a small molecule agonist stabilizes the actomyosin cortex of the apical membrane against injury, which in turn preserves renal function in various murine models of acute kidney injury. Notably, a dynamin agonist simultaneously attenuates podocyte and tubular injury in the genetic murine model of Alport syndrome. Our study provides evidence for the feasibility and highlights the benefits of novel holistic nephron-protective therapies.

Cardamomin protects from diabetes-induced kidney damage through modulating PI3K/AKT and JAK/STAT signaling pathways in rats

BACKGROUND

Diabetic nephropathy is one of the common complications of diabetes mellitus, which seriously affects the life quality and health of patients. In this study, we aimed to investigate the function of cardamonin (CAD) in diabetes-induced kidney damage in rats.

METHODS

The normal rat kidney tubular epithelial cells (NRK-52E) were pre-treated with different doses of CAD and then stimulated with methylglyoxal (MGO). Streptozotocin (STZ) induced diabetes rat model were received different doses of CAD treatment. MTT, EdU, Transwell, and flow cytometry was used to detect cell viability, proliferation, migration, and apoptosis. Western blot analysis was used to detect the expression of apoptosis related proteins, advanced glycation end-products (AGEs), receptor for AGEs (RAGE), epithelial mesenchymal transition (EMT) related proteins, phosphatidylinositol 3-kinase/protein kinase B (PI3K/AKT) pathway related proteins, and janus kinas/signal transducer and activator of transcription 3 (JAK/STAT3) related proteins. ELISA assay was used to detect the levels of tumor necrosis factor-α (TNF-α), interleukin-6 (IL-6), and interleukin-1β (IL-1β). The levels of malondialdehyde (MDA), glutathione (GSH), and superoxide dismutase (SOD) were detected using commercial kit. Hematoxylin and eosin staining was used to assess pathological changes in rat kidney.

RESULTS

Compared with control group, MGO reduced cell viability and proliferation, enhanced migration and apoptosis of NRK-52E cells, while CAD inhibited these effects induced by MGO in NRK-52E cells. Moreover, CAD increased Bcl-2 expression and decreased the expression of Bax and cleaved caspase-3 in MGO-treated NRK-52E cells. Compared with control group, MGO increased the AGEs formation, the expression of RAGE and p-p65, the levels of TNF-α, IL-6, IL-1β, MDA in NRK-52E cells and reduced the levels of GSH and SOD, while treatment of CAD dose-dependently prevented these results. In addition, CAD attenuated MGO-induced EMT of MGO-treated NRK-52E cells. Mechanically, we identified that CAD repressed PI3K/AKT and JAK/STAT3 signaling in NRK-52E cells. Importantly, the kidney injury of diabetes rats was attenuated by CAD. Besides, STZ-induced inflammatory response, oxidative stress, and phosphorylation levels of PI3K, AKT, JAK2, and STAT3 were reduced by CAD in the rats.

CONCLUSION

CAD protects from diabetes-induced kidney damage through modulating PI3K/AKT and JAK/STAT signaling pathways in rats.

Effect of interferon regulatory factor 2 on inflammatory response and oxidative stress in lipopolysaccharide-induced acute kidney injury

Interferon regulatory factor (IRF) 2 plays an important role in lipopolysaccharide (LPS)-induced acute kidney injury (AKI). In this study, we explored the effects of IRF2 on apoptosis, inflammation, and oxidative stress in AKI C57BL/6 male mouse model and HEK293 cells following LPS treatment. To determine the effect of IRF2, short hairpin RNAs in mice and small interfering RNAs in cells were used to knockdown IRF2 expression. IRF2 expression, apoptosis, and severity of inflammatory and oxidative stress in mice and cells were measured. IRF2 levels were upregulated in LPS-treated mice and cells. IRF2 knockdown suppressed the levels of creatinine, blood urea nitrogen, and kidney injury molecule 1 and decreased the renal injury score in mice. Furthermore, IRF2 knockdown inhibited apoptosis and decreased the levels of inflammatory, reactive oxygen species (ROS), and malondialdehyde (MDA), but increased superoxide dismutase (SOD) levels in mice and cells. Furthermore, we found that the Janus kinase (JAK)/ signal transducer and activator of transcription pathway activated by LPS was inhibited by knockdown of IRF2, and enhanced by IRF2 overexpression. IRF2 overexpression increased cell apoptosis, inflammation, and ROS and MDA levels, and decreased SOD levels. However, the effect of IRF2 overexpression was reversed by the JAK inhibitor tofacitinib. Knockdown of IRF2 reduced LPS-induced renal tissue injury in vivo and in vitro through anti-inflammatory and antioxidant stress effects.

Metabolomic Study on Iohexol-Induced Nephrotoxicity in Rats Based on NMR and LC-MS Analyses

Iohexol, the raw material of nonionic X-ray computed tomography (X-CT) contrast medium, is usually injected into the vein before CT angiography diagnosis. It is used for angiography, urography, and lymphography. With the advantages of low contrast density and good tolerance, it is currently one of the most popular contrast media. However, the renal toxicity of iohexol seriously affects its safety use. Therefore, it is of great importance to identify new potential diagnostic biomarkers and therapeutic targets in the process of contrast medium-induced acute kidney injury (CI-AKI) in order to safely use iohexol in clinical practice. In this study, in order to understand the metabolic mechanism of CI-AKI, ultra-high-performance liquid chromatography/quadrupole-Orbitrap-mass spectrometry and ¹H NMR-based metabolomic techniques were utilized to study the metabolic spectra of kidney, plasma, and urine from CI-AKI rats, and a total of 30 metabolites that were closely related to kidney injury were screened out, which were mainly related to 9 metabolic pathways. The results further indicated that iohexol might intensify kidney dysfunction in vivo by disrupting the metabolic pathways in the body, especially through blocking energy metabolism, amino acid metabolism, and promoting inflammatory reactions.

Therapeutic role of Azadirachta indica leaves ethanolic extract against diabetic nephropathy in rats neonatally induced by streptozotocin

Diabetic nephropathy (DN) is manifested by chronic loss of renal function due to damage of glomeruli and renal tubules. Therefore, this study is mainly designed to evaluate the therapeutic role of Azadiracta indica (neem) leaves extract as a novel approach for treatment of DN in rats neonatally induced by streptozotocin (STZ). For this study, 40 offspring were selected after parturition and categorized into four groups (n = 10). Group1: control group, group 2: neem leaves extract supplemented group, group 3: diabetic group that injected with a single dose of STZ and group 4: diabetic group treated with neem extract. The results revealed deleterious histological and ultrstructural changes in the renal tissues of diabetic rats. Such changes included atrophied glomeruli, dilated renal cortical tubules and scattered hemorrhage spots, thickening of glomerular basement membrane, expansion of mesangial matrix and pyknotic podocyte. Additionally, the proximal convoluted tubule and distal tubule showed cytoplasmic vacuolation, vacuolated mitochondria, scattered lipid droplets, lost microvilli and disrupted basal lamina and basal infoldings. Moreover, significant decreased levels of serum antioxidants (SOD&CAT) and significant increased levels of serum MDA, urea and creatinine were noticed in diabetic rats. Neem leaves extract successfully alleviated the histological and ultrastructural as well as biochemical changes induced by diabetes.

Acute Kidney Injury After CT in Emergency Patients with Chronic Kidney Disease: A Propensity Score-matched Analysis

INTRODUCTION

Acute kidney injury (AKI) after intravenous contrast administration for computed tomography (CT) occurs infrequently, but certain patients may be susceptible. This study evaluated AKI incidence among emergency department (ED) patients with pre-existing chronic kidney disease (CKD) undergoing CT exams.

METHODS

This retrospective cohort study in an integrated healthcare system included ED patients previously diagnosed with CKD stages 3-5 (estimated glomerular filtration rate <60 milliliters per minute per 1.73 meters squared over at least three months), undergoing CT exams with or without intravenous contrast, from January 1, 2013-December 31, 2017. We excluded patients with CT prior to (30 days) or following (14 days) index CT and missing serum creatinine (sCr) measurements. We applied propensity score matching, and then multivariable regression adjustment for post-CT ED disposition and ED diagnosis, to calculate adjusted risk of AKI. Secondary patient-centered outcomes included 30-day mortality, end-stage renal disease (ESRD) diagnosis, and dialysis initiation.

RESULTS

Among 103,573 eligible ED patients undergoing CT, propensity score matching yielded 5,589 pairs. Adjusted risk ratio (ARR) for AKI was higher overall for contrast-enhanced CT (1.60; 95% confidence interval [CI], 1.43-1.79). However, secondary outcomes were infrequent: 19/5,589 non-contrast vs 40/5,589 contrast patients with new dialysis initiation at 30 days (adjusted risk 0.3% vs 0.7%; adjusted risk reduction 0.4%; 95% CI, 0.1%-0.7%).

CONCLUSION

In ED patients with chronic kidney disease undergoing CT, intravenous contrast was associated with higher overall adjusted risk of AKI, but patient-centered secondary outcomes were rare. The clinical significance of transient kidney injury after CT is unclear, although patients with advanced chronic kidney disease appear to have elevated risk.

Cardiorenal syndrome: Multi-organ dysfunction involving the heart, kidney and vasculature

Cardiorenal syndrome (CRS) is a multi-organ disease, encompassing heart, kidney and vascular system dysfunction. CRS is a worldwide problem, with high morbidity, mortality, and inflicts a significant burden on the health care system. The pathophysiology is complex, involving interactions between neurohormones, inflammatory processes, oxidative stress and metabolic derangements. Therapies remain inadequate, mainly comprising symptomatic care with minimal prospect of full recovery. Challenges include limiting the contradictory effects of multi-organ targeted drug prescriptions and continuous monitoring of volume overload. Novel strategies such as multi-organ transplantation and innovative dialysis modalities have been considered but lack evidence in the CRS context. The adjunct use of pharmaceuticals targeting alternative pathways showing positive results in preclinical models also warrants further validation in the clinic. In recent years, studies have identified the involvement of gut dysbiosis, uraemic toxin accumulation, sphingolipid imbalance and other unconventional contributors, which has encouraged a shift in the paradigm of CRS therapy.

Prediction Efficiency of Postoperative Acute Kidney Injury in Acute Stanford Type A Aortic Dissection Patients with Renal Resistive Index and Semiquantitative Color Doppler

Objectives

This study is aimed to evaluate the efficiency in early prediction of postoperative persistent acute kidney injury (PAKI) after surgery in acute Stanford type A aortic dissection (AAAD) patients by using Doppler renal resistive index (RRI) and semiquantitative color (SQC) Doppler grade, respectively.

Methods

84 AAAD patients received Sun's surgical management, and 67 patients were enrolled. RRI and SQC Doppler grade were evaluated by ultrasonography, respectively, at 6 hours after surgery. Serum creatinine (sCr) was recorded before operation and at 24 hours, 48 hours, and 72 hours after operation. AKI grade was evaluated according to the classifications of the Acute Kidney Injury Network (AKIN). PAKI is defined as persistent oliguria and/or sCr elevation after 3 days. RRI and SQC Doppler grade were compared, respectively, between the PAKI and non-PAKI groups. Potential predictors were first tested by univariate logistic regression analysis, and a multivariate model was identified to determine the independent predictive ability of RRI and SQC Doppler grade for the PAKI. Receiver operating characteristic (ROC) analysis was performed to compare the diagnostic accuracy between RRI and SQC Doppler grade in early prediction of PAKI by using AKIN classifications as the reference standard.

Results

Of a total of 67 patients enrolled during the study period, 21 (31.3%) patients suffered from PAKI and 8 (11.9%) patients required dialysis. There are significant differences in RRI (0.80 ± 0.09 vs. 0.70 ± 0.05, P=0.002) and SQC Doppler grade (x²=12.193, P=0.007) between the 2 groups with and without PAKI. Univariate analysis showed that RRI, SQC Doppler grade, length of stay in ICU, time of CPB, and length of stay in hospital were significant predictors of PAKI. RRI and the SQC Doppler grade remained independent predictors of PAKI. Area under the curve (AUC) of RRI was 0.855 (95% CI, 0.74–0.96) with cutoff value 0.725 (sensitivity 90.9% and specificity 71.1%), AUC of SQC Doppler grade was 0.642 (95% CI, 0.49–0.79) with cutoff value grade 2 (sensitivity 50% and specificity 73.3%).

Conclusion

Both postoperative RRI and SQC Doppler grade are independent predictors for PAKI after surgery in AAAD patients. Both postoperative RRI and SQC Doppler grade can be obtained rapidly by bedside ultrasound, which is a good tool for early prediction for postoperative PAKI.

Ethyl Vanillin Protects against Kidney Injury in Diabetic Nephropathy by Inhibiting Oxidative Stress and Apoptosis

Diabetes-induced oxidative stress and apoptosis is regarded as a critical role in the pathogenesis of diabetic nephropathy (DN). Treating diabetes-induced kidney damage and renal dysfunction has been thought a promising therapeutic option to attenuate the development and progression of DN. In this study, we investigated the renoprotective effect of ethyl vanillin (EVA), an active analogue of vanillin isolated from vanilla beans, on streptozotocin- (STZ-) induced rat renal injury model and high glucose-induced NRK-52E cell model. The EVA treatment could strongly improve the deterioration of renal function and kidney cell apoptosis in vivo and in vitro. Moreover, treating with EVA significantly decreased the level of MDA and reactive oxygen species (ROS) and stabilized antioxidant enzyme system in response to oxidative stress by enhancing the activity of superoxide dismutase (SOD), catalase (CAT), and glutathione peroxidase (GSH-Px) in vivo and in vitro. Furthermore, EVA also markedly suppressed cleaved caspase-3, Bax, and nuclear transcription factor erythroid 2-related factor (Nrf2) expression in STZ-induced rats. Therefore, these results of our investigation provided that EVA might protect against kidney injury in DN by inhibiting oxidative stress and cell apoptosis.

Incidence and risk of dialysis therapy within 30 days after contrast enhanced computed tomography in patients coded with chronic kidney disease: a nation-wide, population-based study

Background

Patients with chronic kidney disease (CKD) are considered at risk of contrast-induced acute kidney injury and possible subsequent need for dialysis therapy. Computed tomography (CT) is the most commonly performed examination requiring intravenous iodinated contrast media (ICM) injection. The actual risk of dialysis in CKD patients undergoing CT with ICM remains controversial. Furthermore, it is also uncertain whether these at-risk patients can be identified by means of administrative data. Our study is conducted in order to determine the incidence and risk of dialysis within 30 days after undergoing contrast enhanced CT in CKD coded patients.

Methods

This longitudinal, nation-wide, populated-based study is carried out by analyzing the Taiwan National Health Insurance Research Database retrospectively. Patients coded under the diagnosis of CKD who underwent CT are identified within randomly selected one million subjects of the database. From January 2012 to December 2013, 487 patients had undergone CT with ICM. A total of 924 patients who underwent CT without ICM are selected as the control group. Patients with advanced CKD or intensive care unit (ICU) admissions are assigned to the subgroups for analysis. The primary outcome is measured by dialysis events within 30 days after undergoing CT scans. The cumulative incidence is assessed by the Kaplan–Meier method and log-rank test. The risk of 30-day dialysis relative to the control group is analyzed by the Cox proportional hazards model after adjusting for age, sex, and baseline comorbidities.

Results

The numbers and percentages of dialysis events within 30 days after undergoing CT scans are 20 (4.1%) in the CT with ICM group and 66 (7.1%) in the CT without ICM group (p = 0.03). However, the adjusted hazard ratio (aHR) for 30-day dialysis was 0.84 (95% CI [0.46–1.54], p = 0.57), which is statistically non-significant. In both advanced CKD and ICU admission subgroups, there are also no significant differences in 30-day dialysis risks with the aHR of 1.12 (95% CI [0.38–3.33], p = 0.83) and 0.95 (95% CI [0.44–2.05], p = 0.90), respectively.

Conclusions

Within 30 days of receiving contrast-enhanced CT scans, 4.1% of CKD coded patients required dialysis, which appear to be lower compared with subjects who received non-contrast CT scans. However, no statistically significant difference is observed after adjustments are made for other baseline conditions. Thereby, the application of administrative data to identify patients with CKD cannot be viewed as a risk factor for the necessity to undergo dialysis within 30 days of receiving contrast-enhanced CT scans.

Is the risk of contrast-induced nephropathy a real contraindication to perform intravenous contrast enhanced Computed Tomography for non-traumatic acute abdomen in Emergency Surgery Department?

BACKGROUND

Contrast enhanced Computed Tomography (CCT) is the most used imaging test to investigate acute abdominal clinical conditions, because of its high sensitivity and specificity. It is mandatory to make a correct and prompt diagnosis when life threatening abdominal diseases as mesenteric ischemia are suspected. Contrast medium administration was linked to acute renal failure, therefore radiologist often prefer to perform CCT without contrast in patients needing to undergo the exam with increased serum creatinine.  The aim of the review was to focus on the incidence of contrast induced nephropathy in patients presenting non-traumatic acute abdominal clinical conditions, who underwent CCT with intravenous contrast agent administration in emergency setting.

MATERIALS AND METHODS

The systematic review protocol was guided by the Preferred Reporting Items for Systematic Reviews and Meta-analyses Protocol (PRISMA-P). Quality of the evidence will be evaluated using the Grading of Recommendations Assessment, Development and Evaluation (GRADE) methodology.

RESULTS

The strongest currently available evidence on the incidence of post-contrast acute kidney injury (AKI) following intravenous contrast agent administration consists in a meta-analysis of observational studies. Data extracted from meta-analyses demonstrate that, compared with non-contrast CT, CCT was not significantly associated with AKI. Moreover, the risk of AKI (RR=0.79; 95% confidence interval [CI]: 0.62, 1.02; P=.07), death (RR=0.95; 95% CI: 0.55, 1.67; P=.87), and dialysis (RR=0.88; 95% CI: 0.23, 3.43; P=.85) is similar, compared with the risk of AKI in the non-contrast medium group. Furthermore, intravenous low-osmolality iodinated contrast material is a nephrotoxic risk factor, but not in patients with a stable SCr level less than 1.5 mg/dL, therefore many factors other than contrast material could affect PC-AKI rates.

DISCUSSION AND CONCLUSIONS

The benefits of diagnostic information gained from contrast enhanced TC in assessing AA are fundamental in some clinical scenarios. The risk of contrast induced nephropathy (CIN) is negligible in patients with normal renal function but the incidence appears to rise to as high as 25% in patients with pre-existing renal impairment or in the presence of risk factors such as diabetes, advanced age, vascular disease and use of certain concurrent medications. The incidence of CIN/AKI after intravenous contrast administration is very low in general population. Radiologists and referring physicians should be familiar with the risk factors for renal disease, CIN and preventing measures.

Nicorandil for the prevention of contrast-induced nephropathy: A meta-analysis of randomized controlled trials

INTRODUCTION

Nicorandil has been suggested as a preventative strategy against the incidence of contrast-induced nephropathy (CIN). However, results of relevant randomized controlled trials (RCTs) were inconsistent.

AIMS

We performed a meta-analysis of RCTs to evaluate the preventive efficacy of periprocedural treatment of nicorandil against the incidence of CIN.

METHODS

Relevant RCTs were identified via search of PubMed, Embase, and Cochrane's Library databases. Results were pooled using a random-effect model. Subgroup analyses were performed to evaluate the potential influence of administering routes on the efficacy of nicorandil against CIN incidence.

RESULTS

Four RCTs with 709 patients were included. Treatment of nicorandil significantly reduced the incidence of CIN as compared with controls (risk ration [RR]: 0.38, 95% confidence interval [CI]: 0.19 ~ 0.74, P = .005) with moderate heterogeneity (I²  = 33%). Results of subsequent subgroup analysis showed that nicorandil significantly reduced the risk of CIN if orally administered (RR: 0.32, P < .001), but did not if intravenously administered (RR: 0.47, I²  = 68%). Moreover, treatment with nicorandil was associated with significantly less increment of SCr (weight mean difference [WMD]: -3.98%, P < .001) and a tendency of less increment of cystatin C (WMD: -3.86%, P = .08) after 48-hour contrast exposure as compared with controls.

CONCLUSIONS

Periprocedural treatment with nicorandil may be preventative against the incidence of CIN in patients undergoing contrast exposure. The influence of periprocedural nicorandil on clinical outcome in these patients deserves further investigation.

Could Vitamin E Prevent Contrast-Induced Acute Kidney Injury? A Systematic Review and Meta-Analysis

Several clinical studies have proposed a protective role for vitamin E (α-tocopherol) against contrast-induced acute kidney injury (CIAKI). The aim of study was to assess the effects of vitamin E for the prevention of CIAKI. A systematic review and meta-analysis was conducted using MEDLINE, EMBASE, and the Cochrane Central Register of Controlled Trials. Randomized controlled trials (RCTs) reporting the effects of vitamin E on CIAKI development and measurements of renal function were included. Four trials including 623 participants were analyzed in the meta-analysis. All participants received intravenous hydration in addition to vitamin E or placebo. The incidence of the vitamin E group (5.8%) was lower than that of the control group (15.4%). Compared with the control, vitamin E significantly reduced the risk ratio (RR) of CIAKI by 62% (0.38; 95% confidence interval [CI], 0.22, 0.63; P < 0.010). In addition, vitamin E reduced serum creatinine (SCr) increase after contrast administration (standardized mean difference [SMD], -0.27; 95% CI, -0.49, -0.06; P = 0.010). However, changes in glomerular filtration rate (GFR) after contrast administration were not significantly different between vitamin E and the control group (SMD, 0.21; 95% CI, -0.01, 0.43; P = 0.060). Heterogeneity within the available trials was not observed. Our meta-analysis provides evidence that vitamin E plus hydration significantly reduced the risk of CIAKI in patients with renal impairment compared with hydration alone.

State-of-the-Art Pulmonary CT Angiography for Acute Pulmonary Embolism

OBJECTIVE

Pulmonary CT angiography (CTA) is the imaging modality of choice in suspected acute pulmonary embolism (PE). Current pulmonary CTA techniques involve ever lower doses of contrast medium and radiation along with advanced postprocessing applications to enhance image quality, diagnostic accuracy, and provide added value in patient management. The objective of this article is to summarize these current developments and discuss the appropriate use of state-of-the-art pulmonary CTA.

CONCLUSION

Pulmonary CTA is well established as a fast and reliable means of excluding or diagnosing PE. Continued developments in CT system hardware and postprocessing techniques will allow incremental reductions in radiation and contrast material requirements while improving image quality. Advances in risk stratification and prognostication from pulmonary CTA examinations should further refine its clinical value while minimizing the potential harm from overutilization and overdiagnosis.

Cystatin C as a predictor factor in patients with renal cell carcinoma treated by everolimus

BACKGROUND

We evaluated the influence of serum cystatin C (CysC) with respect to other glomerular filtration rate (GFR) markers on the treatment effect of everolimus in a phase II study in patients with metastatic renal cell carcinoma (mRCC).

MATERIALS AND METHODS

Outcomes were from the study's primary analysis. GFR was calculated according to CKD-EPI-sCr equation, CKD-EPI-CysC equation and CKD-EPI-sCr-CysC equation, Modification of Diet in Renal Disease (MDRD) equation and Cockcroft-Gault (CG) equation, serum levels of creatinine (sCr) and CysC before the treatment.

RESULTS

We observed in 56 patients analysed patients high correlation (R Spearman from ±0.69 to ±1.00; P < 0.0001) between CysC level and GFR markers: sCr, CKD-EPI-sCr, CKD-EPI-CysC, CKD-EPI-sCr-CysC, MDRD, GFR (CG) before everolimus therapy. We observed that the adverse independent predictors for everolimus therapy were increased CysC level [HR: 2.85 (95 % CI 1.34-6.05), P = 0.0065], histologic grade G1/2 [HR: 3.38 (95 % CI 1.59-7.20), P = 0.0016] and increased LDH level [HR: 5.59 (95 % CI 2.52-12.40), P < 0.0001]. Worse OS was seen in multivariate analysis in patients with increased cystatin C level before treatment [HR: 2.60 (1.03-2.60), P = 0.0428], increased corrected calcium level [HR: 2.78 (95 % CI 1.03-7.54), P = 0.0441] and increased LDH level before treatment [HR: 2.34 (95 % CI 1.11-4.97), P = 0.0262].

CONCLUSION

Increased serum CysC level in contrast to other studied GFR markers had predictive significance in patients with mRCC.

Prospectively ECG-triggered high-pitch 80 kVp coronary computed tomography angiography with 30 mL of 270 mg I/mL contrast material and iterative reconstruction

BACKGROUND

The smallest diagnostically appropriate amount of contrast medium should be used in coronary computed tomography angiography (CCTA).

PURPOSE

To investigate the feasibility of prospectively ECG-triggered high-pitch CCTA using 30 mL of 270 mg I/mL contrast material, 80 kVp, and iterative reconstruction (IR).

MATERIAL AND METHODS

Eighty-two consecutive patients underwent CCTA with a prospectively ECG-triggered high-pitch protocol. Forty-three patients were examined at 100 kVp with filtered back projection after 60 mL of 370 mg I/mL contrast material was administered. Another 39 patients were examined at 80 kVp with IR after 30 mL of 270 mg I/mL contrast material was administered. Subjective and objective image quality was evaluated for each patient. Radiation doses were estimated and compared.

RESULTS

Mean attenuation, noise and signal-to-noise ratio in 80 kVp group were significantly lower than in 100 kVp group (all P < 0.05), while there was no significant difference in contrast-to-noise ratio (CNR), although a trend towards a lower CNR in 80 kVp group was observed (P = 0.099). The subjective image quality between the two groups was not significantly different (P = 0.905). The effective dose and iodine load in 80 kVp group were reduced by 54% and 64%, respectively, when compared with 100 kVp group.

CONCLUSION

Prospectively ECG-triggered high-pitch CCTA at 80 kVp with 30 mL of 270 mg I/mL contrast material and IR is feasible for patients with BMI less than 25 kg/m(2) and reduces radiation dose and iodine load when compared with the standard CCTA protocol.

Contrast-induced nephropathy in CT: incidence, risk factors and strategies for prevention

In the past, a high percentage of hospital-acquired renal failure was attributed to contrast media. That position is now very controversial. Recently, doubts have been raised regarding the real relationship between acute kidney injury and intravenous contrast media administration. Similarly, statements about specific methods of preventing contrast-inducing nephropathy have been challenged. This review article addresses the controversies of incidence, causation, and prevention in an attempt to help the practicing radiologist adopt methods for their own department.

KEY POINTS

• The reported CIN incidence ranges from 2-12 % following contrast-enhanced CT. • Studies without a non-contrast CT control group may overestimate CIN incidence. • Development and application of a comprehensive CIN prevention strategy is recommended.

Sedation or general anesthesia for transcatheter aortic valve implantation (TAVI)

Transfemoral transcatheter aortic valve implantation (TAVI) is nowadays a routine therapy for elderly patients with severe aortic stenosis (AS) and high perioperative risk. With growing experience, further development of the devices, and the expansion to "intermediate-risk" patients, there is increasing interest in performing this procedure under conscious sedation (TAVI-S) rather than the previously favoured approach of general anesthesia (TAVI-GA). The proposed benefits of TAVI-S include; reduced procedure time, shorter intensive care unit (ICU) length of stay, reduced need for intraprocedural vasopressor support, and the potential to perform the procedure without the direct presence of an anesthetist for cost-saving reasons. To date, no randomized trial data exists. We reviewed 13 non-randomized studies/registries reporting data from 6,718 patients undergoing TAVI (3,227 performed under sedation). Patient selection, study methods, and endpoints have differed considerably between published studies. Reported rates of in-hospital and longer-term mortality are similar for both groups. Up to 17% of patients undergoing TAVI-S require conversion to general anesthesia during the procedure, primarily due to vascular complications, and urgent intubation is frequently associated with hemodynamic instability. Procedure related factors, including hypotension, may compound preexisting age-specific renal impairment and enhance the risk of acute kidney injury. Hypotonia of the hypopharyngeal muscles in elderly patients, intraprocedural hypercarbia, and certain anesthetic drugs, may increase the aspiration risk in sedated patients. General anesthesia and conscious sedation have both been used successfully to treat patients with severe AS undergoing TAVI with similar reported short and long-term mortality outcomes. The authors believe that the significant incidence of complications and unplanned conversion to general anesthesia during TAVI-S mandates the start-to-finish presence of an experienced cardiac anesthetist in order to optimize patient outcomes. Good quality randomized data is needed to determine the optimal anesthetic regimen for patients undergoing TAVI.

Image quality, radiation dose, and diagnostic accuracy of prospectively ECG-triggered high-pitch coronary CT angiography at 70 kVp in a clinical setting: comparison with invasive coronary angiography

PURPOSE

To investigate image quality, radiation dose, and diagnostic performance of prospectively ECG-triggered high-pitch coronary CT angiography (CCTA) at 70 kVp compared to invasive coronary angiography (ICA) as reference standard.

MATERIALS AND METHODS

Forty-three patients underwent prospectively ECG-triggered high-pitch CCTA at 70 kVp using 30 cc (11 g iodine) contrast medium and ICA. Subjective and objective image quality was evaluated for each CCTA study. CCTA performance for diagnosing ≥50% stenosis was assessed. Results were stratified according to heart rate (HR), body mass index (BMI), Agatston score, and image quality.

RESULTS

At CCTA, 94.3% (500/530) of coronary segments were of diagnostic quality. Using ICA as reference standard, sensitivity and accuracy were 100% and 93.0% on a per-patient basis. Per-vessel and per-segment performances were 92.2% and 89.5%; 79.5% and 88.3%, respectively. No differences were found in diagnostic accuracy between different HR, BMI, and calcification subgroups (all P > 0.05) on a per-patient basis. However, low image quality reduced diagnostic accuracy on a per-patient, per-vessel and per-segment basis (all P < 0.05). The mean effective radiation dose was 0.2 ± 0.0 mSv.

CONCLUSION

Our presented protocol results in an effective radiation dose of 0.2 mSv and high diagnostic accuracy for stenosis detection in a selected, non-obese population.

KEY POINTS

Prospectively ECG-triggered high-pitch CCTA at 70 kVp is feasible. This protocol has a high diagnostic accuracy for stenosis detection. The mean effective radiation dose was 0.2 ± 0.0 mSv. Only 30 cc of contrast material is used in this protocol. Low image quality reduced diagnostic accuracy of CCTA.

Automated contrast medium monitoring system for computed tomography--Intra-institutional audit

The aim of this study was to analyze the usage and the data recorded by a RIS-PACS-connected contrast medium (CM) monitoring system (Certegra(®), Bayer Healthcare, Leverkusen, Germany) over 19 months of CT activity. The system used was connected to two dual syringe power injectors (each associated with a 16-row and a high definition 64-row multidetector CT scanner, respectively), allowing to manage contrast medium injection parameters and to send and retrieve CT study-related information via RIS/PACS for any scheduled contrast-enhanced CT examination. The system can handle up to 64 variables and can be accessed via touchscreen by CT operators as well as via a web interface by registered users with three different hierarchy levels. Data related to CM injection parameters (i.e. iodine concentration, volume and flow rate of CM, iodine delivery rate and iodine dose, CM injection pressure, and volume and flow rate of saline), patient weight and height, and type of CT study over a testing period spanning from 1 June 2013 to 10 January 2015 were retrieved from the system. Technical alerts occurred for each injection event (such as system disarm due to technical failure, disarm due to operator's stop, incomplete filling of patient data fields, or excessively high injection pressure), as well as interoperability issues related to data sending and receiving to/from the RIS/PACS were also recorded. During the testing period, the CM monitoring system generated a total of 8609 reports, of which 7629 relative to successful injection events (88.6%). 331 alerts were generated, of which 40 resulted in injection interruption and 291 in CM flow rate limitation due to excessively high injection pressure (>325 psi). Average CM volume and flow rate were 93.73 ± 17.58 mL and 3.53 ± 0.89 mL/s, and contrast injection pressure ranged between 5 and 167 psi. A statistically significant correlation was found between iodine concentration and peak IDR (rs=0.2744, p<0.0001), as well as between iodine concentration and iodine dose (rs=0.3862, p<0.0001) for all CT studies. Automated contrast management systems can provide a full report of contrast use with the possibility to systematically compare different contrast injection protocols, minimize errors, and optimize organ-specific contrast enhancement for any given patient and clinical application. This can be useful to improve and harmonize the quality and consistency of contrast CT procedures within the same radiological department and across the hospital, as well as to monitor potential adverse events and overall costs.

[Contrast-induced acute kidney injury after primary percutaneous coronary interventions: Prevalence, predictive factors, and outcomes]

AIM

To study the incidence, severity, predictive factors, and prognostic value of contrast-induced acute kidney injury (CIAKI) in patients with ST-segment elevation acute coronary syndrome (STSEACS), who have undergone primary percutaneous coronary intervention (PCI).

SUBJECTS AND METHODS

The 2012 KDIGO criteria were used to estimate the incidence of CIAKI in 216 patients (mean age, 64 ± 13 years) admitted to Moscow City Clinical Hospital Sixty-Four and underwent primary PCI for STSEACS (hypertension in 90%, prior myocardial infarction in 27%, chronic kidney disease in 7%, type 2 diabetes mellitus in 21%). Logistic regression analysis was performed to identify predictive factors for CIAKI; following 12 months, its prognosis was assessed by phone.

RESULTS

Forty-three (20%) patients were diagnosed with Stages I (81%) and II (19%) CIAKI. The patients with CIAKI were older; they had higher baseline serum creatinine levels, a higher volume of contrast agent, a higher ratio of contrast medium volume to glomerular filtration rate, and lower left ventricular ejection fraction. Independent predictive factors for CIAKI were identified; these were chronic kidney disease, multivascular injury in the coronary bed, hospital therapy with loop diuretics, nephrotoxic antibiotics, or mineralocorticoid receptor antagonists.

CONCLUSION

The development of CIAKI is associated with poor outcomes, such as higher 30-day mortality and more frequent cardiovascular disease readmissions.

Prevention of contrast-induced nephropathy through a knowledge of its pathogenesis and risk factors

Contrast-induced nephropathy (CIN) is an iatrogenic acute renal failure (ARF) occurring after the intravascular injection of iodinated radiographic contrast media. During the past several years, in many patients undergoing computed tomography, iodinated contrast media have not been used for the fear of ARF, thereby compromising the diagnostic procedure. But recent studies have demonstrated that CIN is rarely occurring in patients with normal renal function and that preexisting chronic renal failure and/or diabetes mellitus represent(s) predisposing condition(s) for its occurrence. After the description of CIN and its epidemiology and pathophysiology, underlying the important role played by dehydration and salt depletion, precautions for prevention of CIN are listed, suggested, and discussed. Maximum priority has to be given to adequate hydration and volume expansion prior to radiographic procedures. Other important precautions include the need for monitoring renal function before, during, and after contrast media injection, discontinuation of potentially nephrotoxic drugs, use of either iodixanol or iopamidol at the lowest dosage possible, and administration of antioxidants. A long list of references is provided that will enable readers a deep evaluation of the topic.