Nephrotoxic effects in high-risk patients undergoing angiography

Effects of a High Dose of the Contrast Medium Iodixanol on Renal Function in Patients Following Percutaneous Coronary Intervention

Iodixanol is associated with lower rates of contrast-induced acute kidney injury (CI-AKI). However, the effects of high volumes of iodixanol on renal function after percutaneous coronary intervention (PCI) have not been fully elucidated. This study evaluates the effects of high-dose (>300 mL) iodixanol on renal function within 72 hours of PCI. We retrospectively reviewed 676 consecutive patients who received high-dose (>300 mL) iodixanol during PCI between October 2015 and December 2017 in 4 centers. Logistic regression analysis was used to identify significant independent predictors for CI-AKI. The incidence of CI-AKI was 3.5% (23/651). In patients administered 300 to 500 mL and >500 mL iodixanol, the incidence of CI-AKI was 3.9% and 1.7%, respectively. In patients with an estimated glomerular filtration rate (eGFR) <60 mL/min/1.73 m², the incidence of CI-AKI was 2.6%. In high-risk and very high-risk patients, stratified by the Mehran risk score, the incidence of CI-AKI was 3.3% and 4.3%, respectively. In patients received high-dose iodixanol (>300 mL), logistic regression analysis demonstrated that female sex, chronic kidney disease, and eGFR were independent risk factors for CI-AKI, but contrast volume was not. The administration of high (300-500 mL) and very high (>500 mL) dose of iodixanol is associated with low rates of CI-AKI.

Advances in the pathogenesis and prevention of contrast-induced nephropathy

With the increasing application of medical imaging contrast materials, contrast-induced nephropathy has become one of the leading causes of iatrogenic renal insufficiency. The underlying mechanism is associated with renal medullary hypoxia, direct toxicity of contrast agents, oxidative stress, apoptosis, immune/inflammation and epigenetic regulation in contrast-induced nephropathy. Up to date, there is no effective therapy for contrast-induced nephropathy, and thus risk predication and effective preventive strategies are keys to reduce the occurrence of contrast-induced nephropathy. It was found that the proper use of contrast medium, personalized hydration, and high-dose statins may reduce the occurrence of contrast-induced nephropathy, while antioxidants have not shown significant therapeutic benefits. Additionally, the role of remote ischemia preconditioning and vasodilators in the prevention of contrast-induced nephropathy needs further study. This review aims to discuss the incidence, pathogenesis, risk prediction, and preventive strategies for contrast-induced nephropathy.

Contrast Media-Different Types of Contrast Media, Their History, Chemical Properties, and Relative Nephrotoxicity

History of contrast dates back to the 1890s, with the invention of the radiograph. Nephrotoxicity has been a main limitation in ideal contrast media (CM). High-osmolar contrast media no longer are in clinical use due to overwhelming evidence supporting greater nephrotoxicity with these CM compared with current CM. Contrast-induced nephropathy (CIN) remains a common cause of in-hospital acute kidney injury. The choice contrast agent is determined mainly by cost and institution practice. This review focuses on the history, chemical properties, and experimental and clinical studies on the various groups of CM and their role in CIN.

Endovascular Coiling in a Patient with Chronic Kidney Disease—A Challenge for Anesthesiologist

A 41-year-old male patient, a known case of autosomal dominant polycystic kidney disease (ADPCKD), presented to our institute with right middle cerebral artery aneurysm for which balloon-assisted endovascular coiling was planned. The major comorbidities were hypertension and end-stage renal disease (ESRD) on hemodialysis, twice weekly. Endovascular coiling was performed under general anesthesia, and special precautions were taken with regard to monitoring, fluid management, use of heparin, and contrast agent. The intraoperative and postoperative course was uneventful, and the patient was discharged after 7 days. In this report, various perioperative challenges of patients with chronic renal failure during coiling are discussed along with the measures to prevent the occurrence of contrast-induced nephropathy.

Endovascular Aspiration Thrombectomy in the Management of Kidney Ischemia: A Case Report

Renal artery occlusion is a serious event that can result in significant impairment or loss of renal function, leading to dialysis dependency. The nonspecific signs and symptoms of its presentation frequently result in a delay in diagnosis, thus contributing to delay in treatment. We report the case of a 53-year old woman who suffered renal artery occlusion, in which the renal perfusion was restored after three days of ischemia, by endovascular aspiration thrombectomy.

Incidence of contrast-induced acute kidney injury (CI-AKI) in high-risk oncology patients undergoing contrast-enhanced CT with a reduced dose of the iso-osmolar iodinated contrast medium iodixanol

Objectives

To determine the incidence of post-contrast acute kidney injury (PC-AKI) and presumed contrast-induced acute kidney injury (CI-AKI) following contrast-enhanced CT (CECT) with intravenous application of a reduced dose of the iso-osmolar contrast agent iodixanol in cancer patients with chronic kidney disease.

Methods

198 oncology patients with a baseline estimated glomerular filtration rate (eGFR) <60ml/min/1.73m² undergoing a total of 237 CECTs using a reduced dose of 60ml iodixanol were retrospectively analyzed. Statistical analysis was performed for the entire cohort and subgroups. The effect of additional risk factors on the occurrence of PC-AKI was evaluated.

Results

The overall PC-AKI incidence was 6.3%. Excluding patients with concurrent medical conditions known to directly and independently impact kidney function and patients with AKI preceding the CT-scan resulted in a presumed CI-AKI incidence of 3.8%. No permanent post-contrast worsening of renal function and no AKI treatment were required. Subgroups considering baseline eGFR yielded PC-AKI incidences of 4.6% (eGFR 45-60ml/min/1.73m², n = 130), 7.4% (eGFR 30-45ml/min/1.73m², n = 95) and 16.7% (eGFR <30ml/min/1.73m², n = 12). Additional patient related risk factors did not show any significant effect on the occurrence of PC-AKI.

Conclusions

Low incidences of PC-AKI/CI-AKI suggest that a reduced dose of an iso-osmolar contrast agent is safe in high-risk oncological patients with impaired renal function.

Contrast-Induced Acute Kidney Injury-Definitions, Epidemiology, and Implications

Contrast-induced acute kidney injury (CI-AKI) is the acute onset of renal injury following exposure to iodinated contrast media. Several definitions have been used, which complicates the estimation of the epidemiological relevance of this condition and comparisons in outcome research. The incidence of CI-AKI increases as a function of patient and procedure complexity in coronary, endovascular, and structural interventions. CI-AKI is associated with a high burden of short- and long-term adverse events, and leads to increased healthcare costs. This review will provide an overview of the definitions, epidemiology, and implications of CI-AKI in patients undergoing coronary, endovascular, and structural catheter-based procedures.

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

Background:

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

Objective:

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

Methods:

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

Results:

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

Conclusion:

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

First in man: percutaneous coronary angioplasty using non-fluoroscopic electro-anatomic mapping

Reduction of radiography exposure and contrast use continue to be challenging goals for interventional cardiology. We present a case where percutaneous coronary intervention was done successfully using an electroanatomic mapping system (NavX™; Abbot Inc. USA); with near zero use of fluoroscopy or contrast agent.

Association between copeptin and contrast-induced nephropathy in patients with ST-elevation myocardial infarction

OBJECTIVE

The aim of this study was to investigate the predictive value of copeptin levels in the development of contrast-induced nephropathy (CIN).

METHODS

A total of 274 patients diagnosed with ST-elevation myocardial infarction (STEMI) and who had undergone primary percutaneous coronary intervention were included in the study. The patients were divided into two groups according to the presence (CIN+) or absence (CIN-) of CIN. These groups were compared in terms of demographic characteristics, laboratory findings and risk factors.

RESULTS

Copeptin levels (10.68±6.43 vs. 7.07±05.53 pmol/l; p<0.001) and peak creatinine (1.46±1.20 vs. 1.03±0.20 mg/dl; p=0.005) were significantly higher in the CIN+ group than in the CIN- group. Female gender was significantly more prevalent in the CIN- group compared to the CIN+ group (19% vs. 8.6%; p<0.05). Copeptin level at hospital admission (OR: 2.36, p=0.005) was found to be an independent predictor for CIN development.

CONCLUSION

Copeptin level is an independent predictor of CIN development in patients with acute STEMI that can be detected rapidly and easily. This result indicates that physicians should be aware of the possibility of CIN development in patients with high copeptin levels and preventive measures should start early.

The impact of percutaneous coronary intervention using the novel dynamic coronary roadmap system

The dynamic coronary roadmap (DCR) is a novel technology that creates a dynamic, motion-compensated, real-time overlay of the coronary arteries on a fluoroscopic image. Whether the DCR reduces contrast volume and enables safe and effective treatment was examined. A total of 146 patients undergoing percutaneous coronary intervention (PCI) from June 2017 to September 2017 in our hospital were retrospectively evaluated. Chronic total occlusion lesions, acute coronary syndrome, and hemodialysis patients were excluded. Patients were divided into the control group (PCI without DCR, 92 patients, 103 lesions) and the DCR group (38 patients, 43 lesions). The primary endpoint was contrast medium volume, and secondary endpoints were radiation dose, fluoroscopy time, and clinical success rate. There was no significant difference in the success rate (100% vs. 100%, P = 1.000) between the groups. Fluoroscopy time (16.3 ± 11.2 min. vs. 11.4 ± 5.5 min, P = 0.007) and contrast medium volume (152.1 ± 73.0 ml vs. 118.8 ± 49.7 ml, P = 0.006) were significantly lower in the DCR group than in the control group. DCR use during PCI was associated with a significant reduction in contrast volume and fluoroscopy time compared to a control group despite similar clinical, lesion, and procedural characteristics.

The Relationship Between Contrast Associated Nephropathy and Coronary Collateral Circulation in very Old Patients

Background: The aim of this study was to investigate whether there is a relationship between coronary collateral circulation (CCC) and contrast associated nephropathy (CAN) in very elderly patients. Methods: Patients aged 90 years or older with at least one major occlusion of the coronary artery proximal or mid-section were included in the study. CCC was graded according to the Rentrop classification. CAN was defined as an increase in blood creatinine value of 25% or more on the second day after coronary angiography. Results: Thirty-six patients who met the study criteria were included in the study. In the study group, CAN developed in 12 patients (CAN (+) group), 24 patients did not develop CAN (CAN (−) group). The creatinine levels before coronary angiography were 1.05 ± 0.12 in the CAN (−) group and 1.22 ± 0.14 in the CAN (+) group. Baseline creatinine values were significantly higher in the CAN (+) group (p = 0.001). The contrast agent used in the CAN (+) group was significantly higher (p = 0.001). In the CAN (+) group, nine patients (43%) had poor collateral circulation, whereas only three patients (20%) had well-developed collateral circulation. In a logistic regression analysis, the collateral class was not a risk factor for CAN, whereas contrast agent volume and basal creatinine were independent predictors of CAN. Conclusion: We found that CCC grade was not associated with the development of CAN in very old patients, but the amount of contrast agent and pre-procedure creatinine values were independent variables in the development of CAN.

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

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

Serum osmolarity as a potential predictor for contrast-induced nephropathy following elective coronary angiography

BACKGROUND AND OBJECTIVES

Contrast-induced nephropathy (CIN) is a relatively common complication following primary coronary angiography (CAG) or percutaneous coronary intervention (PCI), especially in at-risk patients. The goal of this study is to evaluate the role of pre-procedural serum osmolarity as a risk factor for CIN in patients undergoing elective CAG for stable coronary artery disease (CAD).

MATERIALS AND METHODS

A total of 356 stable CAD patients scheduled to undergo CAG or PCI were included in this two-center study. Serum osmolarity was calculated on admission. CIN was defined according to the KDIGO criteria.

RESULTS

There were 45 (12.6%) patients who developed CIN 48-72 h after CAG or PCI. CIN patients had a higher prevalence of diabetes (51.1% in those with CIN vs 24.4% in those without CIN, p < 0.001), higher serum glucose (129 mg/dL in those with CIN vs 108 mg/dL in those without CIN, p < 0.001), blood urea nitrogen (22.4 mg/dL in those with CIN vs 19.0 mg/dL in those without CIN, p = 0.01) and serum osmolarity (294.2 mOsm in those with CIN vs 290.1 mOsm in those without CIN, p < 0.001) levels, had received a higher dose of contrast (250 mL in those with CIN vs 200 mL in those without CIN, p = 0.03) but had lower hemoglobin (12.9 g/dL in those with CIN vs 13.6 g/dL in those without CIN, p = 0.04) level. In multivariate analysis, serum osmolarity [odds ratio (OR) 1.11; 95% confidence interval (CI) 1.04-1.18 for each mOsm/L increase; p = 0.001], diabetes (OR 2.43, 95% CI 1.26-4.71; p = 0.01), C-reactive protein (OR 1.04, 95% CI 1.01-1.08 for each mg/dL increase; p = 0.02) and contrast volume (OR 34.66, 95% CI 1.25-962.22 for each L increase; p = 0.04) remained as independent predictors of CIN. Serum sodium, glucose and blood urea nitrogen contributed to the excess serum osmolarity of CIN patients.

CONCLUSION

Serum osmolarity is a cheap and widely available marker that can reliably predict CIN after CAG or PCI. Future research should focus on determining a clinically optimal cutoff for serum osmolarity that would warrant preventive interventions. Furthermore, later research may investigate the role of serum osmolarity not only as a risk factor but also as a pathogenetic mechanism underlying CIN.

Effects of Changes in Analytic Variables and Contrast Material on Measurement of Computed Tomography Glomerular Filtration Rates in Healthy Candidates

PURPOSE

This study aimed to prospectively assess the effects of changes in analytic variables and contrast material (CM) osmolality when measuring glomerular filtration rate using computed tomography (CT-GFR).

METHODS

One hundred healthy participants were included in this analysis. Glomerular filtration rate was measured by technetium-99m diethylene-triamine-penta-acetic acid (Tc-DTPA), and each participant underwent CT-GFR with iodinated CM (iohexol 240 or iobitridol 400) following a crossover study design. Dynamic renal CT scanning was performed. Patlak plot analysis was used to calculate GFR, selecting either the renal cortex or the whole kidney as the region of interest. The renal cortex was analyzed just before time of the second cortical attenuation peak. The whole kidney was analyzed 60, 80, 100, and 120 seconds after the appearance of CM. Automated GFR calculations were performed using perfusion software at 2 noise reduction levels (medium and strong). The CT-GFRs were compared with GFR measured by Tc-DTPA.

RESULTS

There was no significant difference in CT-GFR with iohexol 240 versus iobitridol 400. The CT-GFR at the renal cortex, for the whole kidney 60 seconds after appearance of CM and calculated by perfusion software with medium noise reduction, did not differ significantly from GFR measured by Tc-DTPA. Whole-kidney CT-GFR at ≥80 seconds after CM appearance and CT-GFR calculated using perfusion CT software with strong noise reduction were lower when compared with GFR measured by Tc-DTPA.

CONCLUSION

Results from CT-GFR were most accurate when the kidney cortex was selected as the region of interest or when using 60-second time point for whole-kidney assessment, regardless of CM osmolarity.

Contrast Induced Nephropathy and 2-Year Outcomes of Iso-Osmolar Compared with Low-Osmolar Contrast Media after Elective Percutaneous Coronary Intervention

Background and Objectives

This study investigated the relative incidence of contrast induced nephropathy (CIN) and long-term outcomes between iso-osmolar contrast media (IOCM) and low-osmolar contrast media (LOCM) undergoing elective percutaneous coronary intervention (PCI).

Methods

A total of 9,431 patients receiving elective PCI were enrolled in the cohort. The patients were divided into IOCM group and LOCM group. Propensity score matching (PSM) was applied to minimize the selection bias between groups.

Results

The multivariate analysis showed that the use of IOCM compared with LOCM did not affect the CIN incidence (odds ratio [OR], 0.912; 95% confidence interval [CI], 0.576–1.446; p=0.696). After PSM, the incidence of CIN was 1.5% and 4.0% in IOCM group (n=979) and LOCM group (n=979), respectively, p=0.001. IOCM significantly reduced the incidence of CIN compared with LOCM (OR, 0.393; 95% CI, 0.214–0.722; p=0.003). After 2 years of follow-up, the all-cause mortality was higher in IOCM group than LOCM group (2.1% vs. 0.9%, p<0.001). Cox regression analysis showed IOCM was not independent risk factor of 2-years all-cause mortality (OR, 0.849; 95% CI, 0.510–1.412; p=0.528). After PSM, the difference of all-cause death between groups disappeared (1.7% vs. 1.9%, p=0.739). Cox regression analysis showed that the use of IOCM compared with LOCM did not affect the incidence of 2-year all-cause mortality (OR, 1.037; 95% CI, 0.534–2.014; p=0.915).

Conclusions

Compared with LOCM, IOCM significantly reduced the incidence of CIN after elective PCI, but had no significant effect on 2-year all-cause mortality.

Radiocontrast Toxicity

Intravenous and intraarterial contrast media are invaluable tools in the diagnosis of anatomic lesions. However, they have been associated with deleterious renal events, ranging from acute kidney injury (iodinated contrast) to nephrogenic systemic fibrosis (gadolinium-containing agents). Contrast-associated acute kidney injury has a wide incidence, likely due to differences in populations studied, with incidence likely overstated due to comorbid conditions at the time of contrast exposure. Pathophysiology includes hemodynamic and direct toxic effects. Preventative strategies include intravenous saline administration, higher urine pH, and statin administration. Importantly, because of fears of contrast-associated acute kidney injury, practitioners may be selecting only the healthiest patients for contrast exposure. Gadolinium-based contrast agents may cause their toxicity through being unbound from their ligand, and certain preparations may be less harmful than others.

Contrast-Induced Kidney Nephropathy in Thoracic Endovascular Aortic Repair: A 2-Year Retrospective Study in 470 Patients

We identified changes in renal function in patients who underwent thoracic endovascular aortic repair (TEVAR) and the factors that may influence renal function. Information on 470 consecutive patients was collected. Kidney function and contrast volume were recorded. Unpaired t test, Spearman correlation, and logistic regression were used for statistical analysis. A Kaplan-Meier curve helped clarify our follow-up findings. Mean contrast volume was 90.5 ± 21.2 mL. The change in serum creatinine was significantly correlated with (1) preexisting renal pathology (P = .033) and (2) aortic dissection (AD) involving the renal arteries (P = .019). The change in serum urea nitrogen (ΔBUN) was only significantly correlated with AD involving the renal arteries (P = .0348). Contrast volume (P = .036, odds ratio = 1.010, 95% confidence interval: 1.001-1.019) was a risk factor for contrast-induced nephropathy (CIN) after TEVAR. Survival rates and renal failure rates among no CIN, CIN, and CIN-acute kidney injury groups at longest 27 months follow-up were significantly different. Creatinine and BUN were generally elevated post-TEVAR. Contrast-induced nephropathy post-TEVAR may correlate with renal comorbidities and renal artery involvement. Contrast volume is risk factor for CIN after TEVAR. More attention needs to be paid to patient renal function during follow-up.

Primary diagnosis of pulmonary embolism with unenhanced MRI for patients not eligible for CTPA: Clinical outcome

Purpose

To follow up the clinical outcome of patients with suspected pulmonary embolism (PE), in those only imaged using unenhanced, free-breathing magnetic resonance imaging (MRI).

Methods and materials

Fifty-seven patients aged 29-99 years (mean 70, SD 18) that could not undergo Computed Tomography Pulmonary Angiography (CTPA) were offered alternative imaging diagnostics in parallel with ongoing methodological studies validating MRI vs CTPA. Contraindications included renal failure (n = 44), severe iodine contrast allergy (n = 10), pregnancy (n = 2) and radioactive iodine therapy (n = 1). The unenhanced MRI protocol was based on free-breathing, steady-state free precession with no cardiac or respiratory gating. Retrospective review of the electronic medical record (EMR) was made of 0-12 months post-imaging and was collected during 2012-2018.

Results

All 57 MRIs were of diagnostic quality and 12 pulmonary embolisms were diagnosed. Of the 57 patients, 44 were already on, or had started anticoagulation therapy due to clinical suspicion of PE. Four of the patients were put on anticoagulation after the positive MRI and 13 were taken off anticoagulation after a negative MRI report. Other diagnoses reported (considering dyspnea) were pleural effusion (n = 24), consolidation (n = 12) and pericardial effusion (n = 2). One patient had a deep vein thrombosis (DVT) within three months of our negative MRI result and then had a stroke within one year. Another patient suffered a stroke within three months of being diagnosed (by MRI) with PE and given anticoagulation as treatment.

Conclusions

Our method supported or altered clinical decision-making and treatment in this cohort. A diagnostic tool for PE without intravenous contrast agent or radiation is of great benefit for certain patients.

Acute kidney injury after platinum-based transcatheter arterial chemoembolization and transarterial infusion chemotherapy in patients with hepatocellular carcinoma

Backgrounds

The incidence of acute kidney injury and the association between acute kidney injury and prognosis have been reported about transcatheter arterial chemoembolization using anthracycline. However, the incidence of acute kidney injury after platinum-based transarterial chemoembolization or transarterial infusion chemotherapy remains unclear. The aim of this study was to investigate association between acute kidney injury after platinum-based transcatheter arterial chemoembolization/transarterial infusion chemotherapy and prognosis in patients with hepatocellular carcinoma.

Methods

We retrospectively analysed 270 sessions in 129 patients who underwent platinum-based transcatheter arterial chemoembolization/transarterial infusion chemotherapy. Acute kidney injury was diagnosed according to the criteria established by the International Club of Ascites. The incidence of acute kidney injury, risk factors for serum creatinine elevation and association between acute kidney injury and prognosis were assessed.

Results

Fifteen cases of acute kidney injury (5.6%, 15/270) developed in 14 patients (10.8%, 14/129). Ascites (coefficient: 0.059, P = 0.006), low estimated glomerular filtration rate (coefficient: −0.008, P = 0.029), diabetes (coefficient: 0.072, P &lt; 0.001) and high albumin–bilirubin grade (albumin–bilirubin grade 2: coefficient: 0.053, P = 0.004; and albumin–bilirubin grade 3: coefficient: 0.103, P &lt; 0.001) were significantly associated with an elevation in serum creatinine levels after transcatheter arterial chemoembolization/transarterial infusion chemotherapy. The development of acute kidney injury was associated with poor prognosis (hazard ratio: 3.18, 95%CI: 1.411–7.171, P = 0.005). Patients with acute kidney injury had a significantly lower survival rate than patients without acute kidney injury (log-rank test; P = 0.034).

Conclusions

The incidence of acute kidney injury after platinum-based transcatheter arterial chemoembolization/transarterial infusion chemotherapy was consistent with that after transcatheter arterial chemoembolization using anthracycline, and the development of acute kidney injury was associated with poor prognosis. Ascites, diabetes, low estimated glomerular filtration rate and high albumin–bilirubin grade were risk factors for serum creatinine elevation after platinum-based transcatheter arterial chemoembolization/transarterial infusion chemotherapy.

Radiological iodinated contrast-induced nephropathy

The use of iodinated contrast media can cause renal toxicity. Whether contrast media are exclusively responsible for kidney damage is currently the subject of debate, given that in most cases, other potential causes of the renal failure are present. With current low-osmolar and iso-osmolar contrast media, the incidence rate of contrast-induced nephropathy is estimated to be <1% in the low-risk population but can increase to 37% in patients who are administered contrast by an intra-arterial administration and/or who have renal failure with an estimated glomerular filtration rate (eGFR) <30mL/min/1.73m². To minimize the risk of renal toxicity, the recommendation is to administer the least amount of contrast possible and ensure appropriate volume expansion by infusing 0.9% saline solution.

Changes in Estimated Glomerular Filtration after Balloon Pulmonary Angioplasty for Chronic Thromboembolic Pulmonary Hypertension

BACKGROUND

Balloon pulmonary angioplasty (BPA) is a novel treatment option for inoperable or persistent chronic thromboembolic pulmonary hypertension (CTEPH). Little is known about renal function in CTEPH patients undergoing BPA.

OBJECTIVES

The aim of this study was to assess the frequency of contrast-induced acute kidney injury (CI-AKI) in patients with CTEPH undergoing BPA and to evaluate the relationship between hemodynamic and renal function.

METHODS

A total of 41 CTEPH patients were included and 250 consecutive BPA sessions were analyzed for frequency of CI-AKI. The serum creatinine (SC) concentration was measured and the glomerular filtration rate (GFR) was estimated using the Modification of Diet in Renal Disease equation before and 72 h after each BPA procedure. CI-AKI was defined as an increase of 25% or 0.5 mg/dL in SC from the baseline value within 48-72 h of contrast administration. SC and GFR were assessed before and after 3-6 months of completing the BPA treatment and correlated with hemodynamic parameters.

RESULTS

The SC concentration and GFR did not change significantly within 72 h after BPA (+1%, p = 0.921, and +4%, p = 0.112, respectively). CI-AKI was noted in 2 cases (0.8%). Significant improvement was noted in GFR (75.4 ± 21.2 vs. 80.9 ± 22.4 mL/min/1.73 m2; p = 0.012) in addition to improvement in right atrial pressure (RAP; 9.1 ± 4.1 to 5.0 ± 2.2 mm Hg; p < 0.001), mean pulmonary artery pressure (49.1 ± 10.7 to 29.8 ± 8.3 mm Hg; p < 0.001), cardiac index (CI; 2.42 ± 0.6 to 2.70 ± 0.6 L/min/m2; p = 0.004), and pulmonary vascular resistance (9.42 ± 3.6 to 4.4 ± 2.3 Wood units; p < 0.001). In a subpopulation of 12 patients with impaired renal function at baseline, the relative increase in GFR was significantly correlated with relative improvement in CI (r = 0.060; p = 0.037), RAP (r = -0.587; p = 0.044), and mixed venous saturation (r = 0.069; p = 0.012).

CONCLUSIONS

Hemodynamically effective BPA procedures improve renal function in patients with CTEPH with a minimal risk of CI-AKI in the course of treatment.

Investigating the Possible Protective Role of Direct Intra-arterial Administration of Mannitol and N-Acetylcysteine and Per Os Administration of Simvastatin Against Contrast-Induced Nephropathy: An Experimental Study in a Rabbit Model

PURPOSE

Contrast-induced nephropathy (CIN) is one of the leading causes of hospital-acquired acute kidney injury due to the use of iodinated contrast media in various interventional procedures like endovascular aneurysm repair. Its pathophysiology remains mostly unclear. The purpose of the present study was to comparatively study the possible protective role of direct intra-arterial administration of mannitol and acetylcysteine and per os administration of simvastatin in a histopathological level.

MATERIALS AND METHODS

In the present study, we administered iopromide directly in the infrarenal aorta of 24 New Zealand white rabbits after laparotomy. Animals were divided in four groups of six: G1 received iopromide with no protection, G2 iopromide with mannitol, G3 iopromide with acetylcysteine, and G4 iopromide with simvastatin. Renal function blood parameters were assessed prior to the administration, and in 48 h; histopathological evaluation of the kidneys was performed.

RESULTS

CIN was evident only in the no protection group G1. Moreover, G1 demonstrated significantly more severe lesions than groups G2, G3, and G4 regarding histopathological findings in glomeruli, vacuolization of tubular epithelial cells, tubular proteinaceous casts, and tubular necrosis. According to our results, intra-arterial administration of mannitol seems to be effective in protection against tubular necrosis.

CONCLUSION

In general, all three agents demonstrated a protective role in preventing the development of CIN, although it seems that there are various pathways that remain to be investigated further.

Global Vascular Guidelines on the Management of Chronic Limb-Threatening Ischemia

GUIDELINE SUMMARY

Chronic limb-threatening ischemia (CLTI) is associated with mortality, amputation, and impaired quality of life. These Global Vascular Guidelines (GVG) are focused on definition, evaluation, and management of CLTI with the goals of improving evidence-based care and highlighting critical research needs. The term CLTI is preferred over critical limb ischemia, as the latter implies threshold values of impaired perfusion rather than a continuum. CLTI is a clinical syndrome defined by the presence of peripheral artery disease (PAD) in combination with rest pain, gangrene, or a lower limb ulceration >2 weeks duration. Venous, traumatic, embolic, and nonatherosclerotic etiologies are excluded. All patients with suspected CLTI should be referred urgently to a vascular specialist. Accurately staging the severity of limb threat is fundamental, and the Society for Vascular Surgery Threatened Limb Classification system, based on grading of Wounds, Ischemia, and foot Infection (WIfI) is endorsed. Objective hemodynamic testing, including toe pressures as the preferred measure, is required to assess CLTI. Evidence-based revascularization (EBR) hinges on three independent axes: Patient risk, Limb severity, and ANatomic complexity (PLAN). Average-risk and high-risk patients are defined by estimated procedural and 2-year all-cause mortality. The GVG proposes a new Global Anatomic Staging System (GLASS), which involves defining a preferred target artery path (TAP) and then estimating limb-based patency (LBP), resulting in three stages of complexity for intervention. The optimal revascularization strategy is also influenced by the availability of autogenous vein for open bypass surgery. Recommendations for EBR are based on best available data, pending level 1 evidence from ongoing trials. Vein bypass may be preferred for average-risk patients with advanced limb threat and high complexity disease, while those with less complex anatomy, intermediate severity limb threat, or high patient risk may be favored for endovascular intervention. All patients with CLTI should be afforded best medical therapy including the use of antithrombotic, lipid-lowering, antihypertensive, and glycemic control agents, as well as counseling on smoking cessation, diet, exercise, and preventive foot care. Following EBR, long-term limb surveillance is advised. The effectiveness of nonrevascularization therapies (eg, spinal stimulation, pneumatic compression, prostanoids, and hyperbaric oxygen) has not been established. Regenerative medicine approaches (eg, cell, gene therapies) for CLTI should be restricted to rigorously conducted randomizsed clinical trials. The GVG promotes standardization of study designs and end points for clinical trials in CLTI. The importance of multidisciplinary teams and centers of excellence for amputation prevention is stressed as a key health system initiative.

Comparative effect of iso-osmolar versus low-osmolar contrast media on the incidence of contrast-induced acute kidney injury in diabetic patients: a systematic review and meta-analysis

BACKGROUND

Contrast-induced acute kidney injury (CI-AKI) is a major adverse effect caused by intravascular administration of iodinated contrast medium. Whether there is a difference in CI-AKI incidence between iso-osmolar (IOCM) and low-osmolar contrast media (LOCM) among diabetic patients is controversial.

METHODS

Randomized controlled trials comparing the nephrotoxic effects between IOCM and LOCM in diabetic patients with or without CKD (eGFR< 60 ml/min/1.73 m2) were included in the analysis. The incidence of CI-AKI was defined as an initial increase in serum creatinine (SCr) concentration of at least 0.5 mg/dl or a rise in creatinine of 25% from baseline.

RESULTS

A total of 2190 patients were included, among whom 1122 patients received IOCM and 1068 received LOCM. When compared to LOCM, IOCM had no significant benefit in preventing CI-AKI (OR = 1.66, [CI: 0.97-2.84], P = 0.06, I2 = 54%). However, the difference between IOCM and LOCM was found when CI-AKI was defined as an absolute SCr increase (≥0.5 mg/dl) rather than a relative SCr increase (≥25%). Further analysis showed that LOCM resulted in more adverse events.

CONCLUSIONS

Whether there is a difference of CI-AKI incidence between IOCM and LOCM in diabetic patients was related to the selected diagnostic criteria. The incidence of adverse events was significantly lower with IOCM when compared with LOCM. Therefore, we suggest that IOCM may be used in diabetic and CKD (eGFR< 60 ml/min/1.73 m2) patients.

Global vascular guidelines on the management of chronic limb-threatening ischemia

Chronic limb-threatening ischemia (CLTI) is associated with mortality, amputation, and impaired quality of life. These Global Vascular Guidelines (GVG) are focused on definition, evaluation, and management of CLTI with the goals of improving evidence-based care and highlighting critical research needs. The term CLTI is preferred over critical limb ischemia, as the latter implies threshold values of impaired perfusion rather than a continuum. CLTI is a clinical syndrome defined by the presence of peripheral artery disease (PAD) in combination with rest pain, gangrene, or a lower limb ulceration >2 weeks duration. Venous, traumatic, embolic, and nonatherosclerotic etiologies are excluded. All patients with suspected CLTI should be referred urgently to a vascular specialist. Accurately staging the severity of limb threat is fundamental, and the Society for Vascular Surgery Threatened Limb Classification system, based on grading of Wounds, Ischemia, and foot Infection (WIfI) is endorsed. Objective hemodynamic testing, including toe pressures as the preferred measure, is required to assess CLTI. Evidence-based revascularization (EBR) hinges on three independent axes: Patient risk, Limb severity, and ANatomic complexity (PLAN). Average-risk and high-risk patients are defined by estimated procedural and 2-year all-cause mortality. The GVG proposes a new Global Anatomic Staging System (GLASS), which involves defining a preferred target artery path (TAP) and then estimating limb-based patency (LBP), resulting in three stages of complexity for intervention. The optimal revascularization strategy is also influenced by the availability of autogenous vein for open bypass surgery. Recommendations for EBR are based on best available data, pending level 1 evidence from ongoing trials. Vein bypass may be preferred for average-risk patients with advanced limb threat and high complexity disease, while those with less complex anatomy, intermediate severity limb threat, or high patient risk may be favored for endovascular intervention. All patients with CLTI should be afforded best medical therapy including the use of antithrombotic, lipid-lowering, antihypertensive, and glycemic control agents, as well as counseling on smoking cessation, diet, exercise, and preventive foot care. Following EBR, long-term limb surveillance is advised. The effectiveness of nonrevascularization therapies (eg, spinal stimulation, pneumatic compression, prostanoids, and hyperbaric oxygen) has not been established. Regenerative medicine approaches (eg, cell, gene therapies) for CLTI should be restricted to rigorously conducted randomizsed clinical trials. The GVG promotes standardization of study designs and end points for clinical trials in CLTI. The importance of multidisciplinary teams and centers of excellence for amputation prevention is stressed as a key health system initiative.

Acute effects of Iodixanol on renal function after intra-arterial administration in patients with end-stage kidney disease

BACKGROUND

Contrast-induced acute kidney injury (CI-AKI), a potentially life-threatening complication of iodinated contrast media in patients with impaired renal function, has attracted increasing attention in recent years. There is overwhelming evidence that the most important pre-disposing factor for a contrast-medium induced nephropathy is the pre-existence of a renal impairment.

METHODS

The registry was performed as a part of a quality management project in the Dresden-Friedrichstadt heart catheter laboratory. In compliance with the Declaration of Helsinki/Somerset West, 9,026 patients were included between 2010 and 2015. 100 patients of these were participants in a chronic dialysis program. All patients were dialyzed on the day before angiography. In all patients a coronary angiography, in 28 patients a stent implantation and in 12 patients a surgical reconstruction had to be performed. Prior to the intervention and one, two and three days thereafter the serum creatinine was measured.

RESULTS

Up to the third day after application of the iodinated contrast medium no significant changes of the serum creatinine (baseline value: 423.3±42.6μmol/l) occurred (ANOVA for repeated measures: p = 0.507). On average, a slight decrease of the serum creatinine was found.All patients remained in their routine dialysis-program. 18 out of 100 died during the next three months after the procedure.

CONCLUSION

The study revealed that the coronary angiography using Iodixanol as iodinated contrast medium did not result in an increase of serum creatinine, which was drastically elevated in these patients before application of the iodinated contrast medium.

Immediate and delayed hypersensitivity after intra-arterial injection of iodinated contrast media: a prospective study in patients with coronary angiography

OBJECTIVES

While hypersensitivity reactions (HSR) to intravenously administered iodinated contrast media (ICM) have been well studied, not much is known about HSR to intra-arterially administered ICM.

METHODS

A prospective observational study was performed to evaluate coronary angiography (CAG)-induced ICM hypersensitivity in patients who underwent CAG using ICM including ioversol, a low-osmolar non-ionic monomer, and iodixanol, an iso-osmolar non-ionic dimer. The HSR were investigated through in-patient monitoring after CAG and telephone interview after discharge.

RESULTS

A total of 714 patients were enrolled during the observation period, of whom 26 (3.6%) showed immediate HSR and 108 (15.1%) showed delayed HSR. With regard to severity, proportion of immediate HSR grades 1, 2, and 3 was 57.7%, 38.5%, and 3.8%, respectively, whereas that of delayed HSR grades 1, 2, and 3 was 85.2%, 13.9%, and 0.9%, respectively. Multivariate analysis revealed that previous intra-arterial exposure to ICM was an independent risk factor for immediate HSR (odds ratio (OR) 2.92, 95% confidence interval (CI) 1.22-6.96; p = 0.015). Iodixanol was a significant risk factor for delayed HSR (OR 1.61, 95% CI 1.07-2.43; p = 0.024) and correlated with a higher incidence of delayed HSR within 24-h post-ICM administration compared to ioversol.

CONCLUSION

The incidence rate of immediate and delayed HSR in intra-arterially administered ICM was 3.6% and 15.1%, respectively. Previous exposure to intra-arterially administered contrast media was a significant risk factor for immediate HSR. Compared to ioversol, iodixanol was associated with relatively earlier and more frequent delayed HSR.

KEY POINTS

• In this prospective study, the incidence of immediate and delayed hypersensitivity in intra-arterial injection of contrast media during coronary angiography was 3.6% and 15.1%, respectively. • Delayed hypersensitivity reactions were more common but less severe than immediate hypersensitivity reactions during coronary angiography. • Previous exposure to ICM via intra-arterial route was a significant risk factor for immediate hypersensitivity to intra-arterial contrast medium.

Bi-DTPA as a high-performance CT contrast agent for in vivo imaging

Clinically used iodinated computer tomography (CT) contrast agents suffer from low sensitivity, and the emerging lanthanide-chelates and CT imaging nanoagents raise great safety concerns. The fusion of high sensitivity and good biocompatibility is highly desired for the development of CT contrast agents. Herein, we propose a facile and green one-pot synthesis strategy for the fabrication of a small molecular CT contrast agent, Bi-diethylene triamine pentaacetate acid (DTPA) complex, for high-performance CT and spectral CT imaging. The Bi-DTPA exhibits yield of near 100%, outstanding water solubility, favorable biocompatibility, large-scale production capability, and superior X-ray attenuation ability, and is successfully applied in high-quality in vivo kidney imaging and gastrointestinal tract CT imaging and appealing spectral CT imaging. The proposed contrast agent can be rapidly excreted from body, avoiding the potential side effects caused by the long-term retention in vivo. Furthermore, our design shows great potential in developing diverse multifunctional contrast agents via chemical modification. The proposed Bi-DTPA with unique superiorities shows a bright prospect in clinic CT imaging, especially spectral CT imaging, and lays down a new way for the design of high-performance CT contrast agents with great clinical transformation potential.

Prevention of contrast-induced nephropathy by adequate hydration combined with isosorbide dinitrate for patients with renal insufficiency and congestive heart failure

BACKGROUND

Adequate hydration remains the mainstay of contrast-induced nephropathy prevention, and nitrates could reduce cardiac preload.

HYPOTHESIS

This study aimed to explore the adequate hydration with nitrates for patients with chronic kidney disease (CKD) and congestive heart failure (CHF) to reduce the risk of contrast-induced nephropathy (CIN) and at the same time avoid the acute heart failure.

METHODS

Three hundred and ninty-four consecutive patients with CKD and CHF undergoing coronary procedures were randomized to either adequate hydration with nitrates (n = 196) or to routine hydration (control group; n = 198). The adequate hydration group received continuous intravenous infusion of isosorbide dinitrate combined with intravenous infusion of isotonic saline at a rate of 1.5 mL/kg/h during perioperative period. The definition of CIN was a 25% or 0.5 mg/dL rise in serum creatinine over baseline. This trial is registered with www.clinicaltrials.gov, number NCT02718521.

RESULTS

Baseline characteristics were well-matched between the two groups. CIN occurred less frequently in adequate hydration group than the control group (12.8% vs 21.2%; P = 0.018). The incidence of acute heart failure did not differ between the two groups (8 [4.08%] vs 6[3.03%]; P = 0.599). Cumulative major adverse events (death, myocardial infarction, stoke, hospitalization for acute heart failure) during the 90-day follow-up were lower in the adequate hydration with nitrates group (P = 0.002).

CONCLUSIONS

Adequate hydration with nitrates can safely and effectively reduce the risk of CIN in patients with CKD and CHF.

[Management of renal failure in old patients undergoing percutaneous cardiac interventions]

The elderly benefit from the advances of the interventional cardiology, especially for coronary artery disease and aortic valve stenosis. The prevalence of comorbidities is high in old population, but the benefit-risk balance remains often positive. Chronic kidney disease is frequent and amplifies the risks of contrast-induced nephropathy and acute kidney injury with an impact on clinical course and outcomes, and additional costs. Preventive strategies recognized as efficient to limit renal adverse events must be applied. Future approach may involve research in vulnerable old patients undergoing cardiac interventions.

Contrast enhancement efficacy of iodinated contrast media: Effect of molecular structure on contrast enhancement

Purpose

To investigate the contrast enhancement in DSA images based on the X-ray absorption characteristics of iodinated contrast media.

Methods

We have derived a new formula of predicting the pixel value ratio of two different contrast media and designate it as "Contrast Enhancement Ratio (CER)". In order to evaluate the accuracy of CER, we have evaluated the relationship between CER and pixel value ratio for all combinations of eleven iodinated contrast media. The non-ionic iodinated contrast media, iopamidol, iomeprol, iopromide, ioversol, iohexol, and iodixanol, were evaluated in this study. Each contrast medium was filled in the simulated blood vessel in our constructed anthropomorphic phantom, and DSA images were obtained using an angiographic imaging system. To evaluate the contrast enhancement of the contrast medium, the mean pixel value was calculated from all pixel values in the vascular image.

Results

CER was indicated to agree well with the pixel value ratio of two different contrast medium solutions and showed a good accuracy. CER was also shown to have a good linear relation to the pixel value ratio when the iodine concentration was constant. This means that the molecular structure of the contrast media affects contrast enhancement efficacy. Furthermore, in evaluation of contrast enhancement of iodinated contrast media by using the weight factor (that is a key factor in CER) ratio, Iodixanol, and iopamidol, and iomeprol have the same ability of contrast enhancement in DSA images, and iohexol shows the lowest ability.

Conclusions

We have derived a new formula (CER) of predicting the pixel value ratio of two different contrast medium solutions, and shown that CER agreed well with the pixel value ratio for blood vessel filled with eleven contrast media.

Inflammatory milieu in contrast-induced nephropathy: a prospective single-center study

Background

Acute kidney injury (AKI) caused by contrast exposure is a common problem, which may cause a significant increase in patients in-hospital stay and therefore the cost of treatment. This study was conducted to evaluate the role of inflammation, inflammatory markers in predicting contrast induced nephropathy (CIN). This is a prospective study that was carried out in a major tertiary referral hospital in Jordan.

Methods

Clinical data, blood and urine samples were collected from all patients admitted to the cardiology unit. All patients who agreed to participate in the study had creatinine level analysis 48-72 hours after the procedure. The CIN was defined as an increase in serum creatinine by 25% or 44 μmol/L from the baseline within 48-72 hours after the contrast administration. Patients with stage 4, 5 renal failure, patients on dialysis, and patients with recent intravenous contrast use, active infection or cancer were excluded from the study.

Results

Of the total 202 patients, 30 (14.8%) developed CIN. The incidence rate was 21.1% among females and 12.4% among males. In the multivariate analysis, beside eGFR, diuretics, and alkaline phosphatase, IL-33 was significantly associated with CIN, while the other cytokines did not to show this an association.

Conclusion

Serum level of IL-33 was a significant predictor for development of CIN. Good clinical judgment and high serum levels of IL-33 may stratify patients into low and high risk for CIN.

Effects of Iodixanol on Respiratory Functions during Coronary Angiography and the Role of Body Composition

Purpose

The purposes of this study are to assess the acute effects of iodixanol, an iso-osmolar contrast media, on pulmonary functions and to evaluate the body composition in order to find out its role in causing this deterioration.

Methods

35 male and 25 female patients undergoing diagnostic coronary angiography (CA) were enrolled in the study. Before CA, all patients' body compositions were evaluated by measuring their body mass indexes (BMIs) and waist-to-hip ratios (WHRs). Total body waters (TBWs), fat masses (FMs), fat-free masses (FFMs), and basal metabolism rates (BMRs) were measured via bioimpedance analysis. The CA was performed via radial artery route using iodixanol in every patient. The pulmonary function tests of these patients were performed before, during, and 2 hours after the CA. FEV1∆, FEF_25–75%∆, and FVC∆ parameters were calculated by subtracting the measured baseline value from the measurement after the CA.

Results

Angiography caused significant reduction in forced expiratory volume in 1 sec (FEV1, from 94.17 ± 18.83 to 84.45 ± 18.31, p < 0.0001), forced vital capacity (FVC, from 96.57 ± 15.82 to 88.31 ± 17.96, p < 0.0001), and forced expiratory flow at 25–75% (FEF_25–75% from 82.54 ± 24.26 to 72.11 ± 25.41, p=0.001) and remained lower after 2 h after CA in male patients, respectively. FEV1 values were 103.40 ± 17.79 to 94.96 ± 17.063 (p=0.004); FVC values were 107.20 ± 19.03 to 99.08 ± 20.56 (p=0.009); and FEF_25–75% values were 83.92 ± 24.30 to 73.24 ± 20.45 (p=0.005) before and after CA and remained lower after 2 h after CA in female patients, respectively. FEV1/FVC ratio remained unchanged. FEF_25–75%∆ was statistically correlated with FFM, TBW, and WHR (p < 0.05; r=−0.344, r=−0.347, and r=0.357, resp.), and FVC∆ was correlated with WHR in male patients (p=0.018, r=397).

Conclusions

Our data suggested that diagnostic CA using iodixanol, an iso-osmolar contrast media, leads significant impairment in respiratory functions. Due to the persistence of these reductions even 2 hours after CA, ventilatory functions should be considered especially in patients whose body compositions or hydration levels are not within the desired physiological range.

Acute kidney injury complicating nephrotic syndrome of minimal change disease

Minimal change disease accounts for 70% to 90% of cases of nephrotic syndrome in children. It also causes nephrotic syndrome in adults, including patients older than age 60. Renal function is altered moderately in approximately 20% to 30% of patients because foot-process fusion impairs filtration of water and solutes. The glomerular filtration rate is reduced by approximately 20% to 30% and returns to baseline with remission of proteinuria. Over the past 50 years, a number of publications have reported cases of acute kidney injury occurring in approximately one-fifth to one-third of adult cases in the absence of prior or concomitant renal disease. Clinical attributes point to a male predominance, age >50, massive proteinuria, severe hypoalbuminemia, a background of hypertension and vascular lesions on kidney biopsy, along with ischemic tubular necrosis. Acute kidney injury may require dialysis for weeks or months until remission of proteinuria allows resolution of oliguria. In some cases, renal function does not recover. An effect of endothelin-1-induced vasoconstriction at the onset of proteinuria has been proposed to explain tubular cell ischemic necrosis. The main factors causing acute kidney injury in patients with minimal change disease are diuretic-induced hypovolemia and nephrotoxic agents. Acute kidney injury is uncommon in children in the absence of intercurrent complications. Infection, nephrotoxic medication, and steroid resistance represent the main risk factors. In all patients, the goal of supportive therapy is essentially to buy time until glucocorticoids obtain remission of proteinuria, which allows resolution of renal failure.

The Role of Noncontrast CT in the Evaluation of Surgical Abdomen Patients

Acute surgical abdomen is commonly encountered in the ED and CT is widely used as an informative diagnostic tool to evaluate potential surgical indications. However, the adverse effects of contrast material used in CTscanning have been documented. We sought to delineate the role of noncontrast CT in the evaluation of patients with acute surgical abdomen. Between August 2015 and December 2015, patients with nontraumatic surgical abdomen who underwent preoperative CT were enrolled in the current study. The patients for whom the CT results permitted surgical decision-making were the focus of this study. The disease entities included acute appendicitis, acute cholecystitis, hollow organ perforation, mechanical bowel obstruction, intra-abdominal abscess that could not be drained percutaneously, and ischemic bowel disease. The results of contrast-enhanced and noncontrast CT were compared and analyzed. The surgical conditions identifiable by noncontrast CT were recorded. In total, 227 patients were enrolled in the study. In 90.7 per cent of patients overall, the findings indicating the need for surgical treatment were visualized on both the noncontrast and contrast-enhanced images (acute appendicitis: 89.3%, acute cholecystitis: 89.7%, hollow organ perforation: 97.4%, bowel obstruction: 100%, intra-abdominal abscess: 100%, and ischemic bowel disease: 55.6%). Noncontrast CT provides benefit for critical decision-making. Body mass index may affect the accuracy of noncontrast imaging in the evaluation of patients with surgical abdomen. In some specific situations, contrast enhancement remains necessary.