Risk prediction models for contrast induced nephropathy: systematic review

Systematic review of prognostic prediction models for acute kidney injury (AKI) in general hospital populations

OBJECTIVE

Critically appraise prediction models for hospital-acquired acute kidney injury (HA-AKI) in general populations.

DESIGN

Systematic review.

DATA SOURCES

Medline, Embase and Web of Science until November 2016.

ELIGIBILITY

Studies describing development of a multivariable model for predicting HA-AKI in non-specialised adult hospital populations. Published guidance followed for data extraction reporting and appraisal.

RESULTS

14 046 references were screened. Of 53 HA-AKI prediction models, 11 met inclusion criteria (general medicine and/or surgery populations, 474 478 patient episodes) and five externally validated. The most common predictors were age (n=9 models), diabetes (5), admission serum creatinine (SCr) (5), chronic kidney disease (CKD) (4), drugs (diuretics (4) and/or ACE inhibitors/angiotensin-receptor blockers (3)), bicarbonate and heart failure (4 models each). Heterogeneity was identified for outcome definition. Deficiencies in reporting included handling of predictors, missing data and sample size. Admission SCr was frequently taken to represent baseline renal function. Most models were considered at high risk of bias. Area under the receiver operating characteristic curves to predict HA-AKI ranged 0.71-0.80 in derivation (reported in 8/11 studies), 0.66-0.80 for internal validation studies (n=7) and 0.65-0.71 in five external validations. For calibration, the Hosmer-Lemeshow test or a calibration plot was provided in 4/11 derivations, 3/11 internal and 3/5 external validations. A minority of the models allow easy bedside calculation and potential electronic automation. No impact analysis studies were found.

CONCLUSIONS

AKI prediction models may help address shortcomings in risk assessment; however, in general hospital populations, few have external validation. Similar predictors reflect an elderly demographic with chronic comorbidities. Reporting deficiencies mirrors prediction research more broadly, with handling of SCr (baseline function and use as a predictor) a concern. Future research should focus on validation, exploration of electronic linkage and impact analysis. The latter could combine a prediction model with AKI alerting to address prevention and early recognition of evolving AKI.

Development of a preprocedure nomogram for predicting contrast-induced acute kidney injury after coronary angiography or percutaneous coronary intervention

Most of the risk models for predicting contrast-induced acute kidney injury (CI-AKI) are available for postcontrast exposure prediction, thus have limited values in practice. We aimed to develop a novel nomogram based on preprocedural features for early prediction of CI-AKI in patients after coronary angiography (CAG) or percutaneous coronary intervention (PCI). A total of 245 patients were retrospectively reviewed from January 2015 to January 2017. Least absolute shrinkage and selection operator (Lasso) regression model was applied to select most strong predictors for CI-AKI. The CI-AKI risk score was calculated for each patient as a linear combination of selected predictors that were weighted by their respective coefficients. The discrimination of nomogram was assessed by C-statistic. The occurrence of CI-AKI was 13.9% (34 out of 245). We identified ten predictors including sex, diabetes mellitus, lactate dehydrogenase level, C-reactive protein, years since drinking, chronic kidney disease (CKD), stage of CKD, stroke, acute myocardial infarction, and systolic blood pressure. The CI-AKI prediction nomogram obtained good discrimination (C-statistic, 0.718, 95%CI: 0.637-0.800, p = 7.23 × 10^-5). The cutoff value of CI-AKI risk score was -1.953. Accordingly, the novel nomogram we developed is a simple and accurate tool for preprocedural prediction of CI-AKI in patients undergoing CAG or PCI.

Cost-effectiveness of Common Diagnostic Approaches for Evaluation of Asymptomatic Microscopic Hematuria

IMPORTANCE

Asymptomatic microscopic hematuria (AMH) is highly prevalent and may signal occult genitourinary (GU) malignant abnormality. Common diagnostic approaches differ in their costs and effectiveness in detecting cancer. Given the low prevalence of GU malignant abnormality among patients with AMH, it is important to quantify the cost implications of detecting cancer for each approach.

OBJECTIVE

To estimate the effectiveness, costs, and incremental cost per cancer detected (ICCD) for 4 common diagnostic approaches evaluating AMH.

DESIGN, SETTING, AND PARTICIPANTS

A decision-analytic model-based cost-effectiveness analysis using inputs from the medical literature. PubMed searches were performed to identify relevant literature for all key model inputs, each of which was derived from the clinical study with the most robust data and greatest applicability. Analysis included adult patients with AMH on routine urinalysis with subgroups of high-risk patients (males, smokers, age ≥50 years) seen in the primary care or urologic referral setting.

INTERVENTIONS

Four diagnostic approaches were evaluated relative to the reference case of no evaluation: (1) computed tomography (CT) alone; (2) cystoscopy alone; (3) CT and cystoscopy combined; and (4) renal ultrasound and cystoscopy combined.

MAIN OUTCOMES AND MEASURES

At termination of the diagnostic period, cancers detected, costs (payer perspective), and ICCD per 10 000 patients evaluated for AMH.

RESULTS

Of the 4 diagnostic approaches analyzed, CT alone was dominated by all other strategies, detecting 221 cancers at a cost of $9 300 000. Ultrasound and cystoscopy detected 245 cancers and was most cost-effective with an ICCD of $53 810. Replacing ultrasound with CT detected just 1 additional cancer at an ICCD of $6 480 484. Ultrasound and cystoscopy remained the most cost-effective approach in subgroup analysis. The model was not sensitive to any inputs within the proposed ranges. Using probabilistic sensitivity analysis, ultrasound and cystoscopy was the dominant strategy in 100% of simulations.

CONCLUSIONS AND RELEVANCE

The combination of renal ultrasound and cystoscopy is the most cost-effective among 4 diagnostic approaches for the initial evaluation of AMH. The use of ultrasound in lieu of CT as the first-line diagnostic strategy will optimize cancer detection and reduce costs associated with evaluation of AMH. Given our findings, we need to critically evaluate the appropriateness of our current clinical practices, and potentially alter our guidelines to reflect the most effective screening strategies for patients with AMH.

Prophylactic hydration to prevent contrast-induced nephropathy: much ado about nothing?

Clinical guidelines recommend prophylactic hydration to reduce the risk of contrast-induced nephropathy in high-risk patients, including those with chronic kidney disease. A recent single-center randomized trial showed no significant difference in the incidence of contrast-induced nephropathy in ambulatory patients with stage 3 chronic kidney disease who were randomized to no prophylactic hydration versus normal saline hydration. While these results may identify patients who are less likely to benefit from prophylactic hydration, nephrologists and interventionalists should carefully consider the generalizability of these results to individual patients.

Pre-Procedural Risk Score of Contrast-Induced Nephropathy in Elderly Patients Undergoing Elective Coronary Angiography

To establish a scoring model to predict the risk of contrast-induced nephropathy (CIN) in elderly patients undergoing elective coronary angiography (CAG).A total of 1286 patients aged > 65 years who had undergone elective CAG between August 2009 and February 2013 were enrolled in this study. They were randomly (3:2) assigned to a development (n = 756) or validation dataset (n = 530). Independent predictors of CIN were identified by using logistic regression and were assigned a weighted integer, which was used to establish a score model.CIN incidence in the development set was 6.3%. The risk score model contained 3 variables (with the weighted integer): age > 75 years (1.5), creatinine clearance (CrCl) < 60 mL/minute (1), and congestive heart failure (CHF) (1.5). CIN incidence was 3.1%, 9.1%, and 29.0% in the low-risk group (≤ 1), moderate risk group (1 - 3), and high-risk group (≥ 3), respectively. The risk model demonstrated good prediction value in the development (c-statistic = 0.727) and validation (c-statistic = 0.695) datasets. Compared to the non-CIN group, the CIN group had a significantly higher rate of inhospital major adverse cardiac events (P < 0.01).The risk score model with 3 variables, namely age > 75 years, CrCl < 60 mL/minute, and CHF, is a clinical prediction tool for CIN in elderly patients before elective CAG. CIN is one of the independent risk factors of major adverse cardiac events (MACE).

A Nomogram to Predict Contrast Induced Nephropathy in Patients Undergoing Percutaneous Coronary Intervention

Contrast-induced nephropathy (CIN) is the third leading cause of hospital-acquired acute kidney injury (AKI). Emerging evidence has revealed that soluble klotho (sklotho) could be a novel biomarker for early AKI diagnosis. The aims of this study were to assess the predictive role of sklotho for CIN and to develop a prediction nomogram in patients undergoing percutaneous coronary intervention (PCI). This study is registered on Clinicaltrials.gov (NCT 02650336).Patients aged 18 years or older undergoing planned PCI were prospectively recruited between May 2014 and July 2015. CIN was defined as an increase in serum creatinine of 0.5 mg/dL within 48-72 hours after the procedure. Plasma sklotho was measured by enzyme linked immunosorbent assay (ELISA). Stratified analysis, interaction test, covariate screening, and curve fitting were performed to explore the association between sklotho and CIN. A nomogram was then developed and validated using the bootstrapped technique.A total of 192 patients aged 54.75 ± 12.19 years were selected, 32 (16.7%) of whom were diagnosed with CIN. A logistic regression model indicated significant associations between CIN and sklotho, age > 75 years, diabetes, and the Mehran risk score. Saturation effects analysis detected a two-stage change between sklotho and CIN, with the inflection point was 477.4 pg/mL. The area under the ROC curve was 0.758 and the sensitivity and specificity of this point were 90.6% and 53.9%, respectively. A nomogram was developed for the prediction of CIN and showed a bootstrapped-corrected area under the curve value of 0.913. In addition, sklotho significantly increased the predictive value of the nomogram.A strong association between sklotho and CIN was identified in patients undergoing elective PCI. A lower level of sklotho would be well correlated with CIN. The nomogram with sklotho is a useful tool to predict CIN in patients who will undergo PCI.

Agreement Between Serum Assays Performed in ED Point-of-Care and Hospital Central Laboratories

INTRODUCTION

Point-of-care (POC) testing allows for more time-sensitive diagnosis and treatment in the emergency department (ED) than sending blood samples to the hospital central laboratory (CL). However, many ED patients have blood sent to both, either out of clinical custom, or because clinicians do not trust the POC values. The objective of this study was to examine the level of agreement between POC and CL values in a large cohort of ED patients.

METHODS

In an urban, Level I ED that sees approximately 120,000 patients/year, all patients seen between March 1, 2013, and October 1, 2014, who had blood sent to POC and CL labs had levels of agreement measured between serum sodium, potassium, blood urea nitrogen (BUN), creatinine, and hematocrit. We extracted data from the hospital's clinical information system, and analyzed agreement with the use of Bland-Altman plots, defining both 95% confidence intervals (CIs) and more conservative CIs based on clinical judgment.

RESULTS

Out of 163,661 patients seen during the study period, 14,567 had blood samples sent both for POC and CL analysis. Using clinical criteria, the levels of agreement for sodium were 98.6% (within 5mg/dL), for potassium 90.7% (0.5 mmol/L), for BUN 89.0% (within 5 mg/dL), for creatinine 94.5% (within 0.3 mg/dL), for hematocrit 96.5% (within 5 g/dL).

CONCLUSION

Agreement between POC and CL values is excellent. Restricting the analysis to clinically important levels of agreement continues to show a high level of agreement. The data suggest that sending a serum sample to the hospital CL for duplicate assays is unnecessary. This may result in substantial savings and shorter ED lengths of stay.

Predicting AKI in emergency admissions: an external validation study of the acute kidney injury prediction score (APS)

OBJECTIVES

Hospital-acquired acute kidney injury (HA-AKI) is associated with a high risk of mortality. Prediction models or rules may identify those most at risk of HA-AKI. This study externally validated one of the few clinical prediction rules (CPRs) derived in a general medicine cohort using clinical information and data from an acute hospitals electronic system on admission: the acute kidney injury prediction score (APS).

DESIGN, SETTING AND PARTICIPANTS

External validation in a single UK non-specialist acute hospital (2013-2015, 12 554 episodes); four cohorts: adult medical and general surgical populations, with and without a known preadmission baseline serum creatinine (SCr).

METHODS

Performance assessed by discrimination using area under the receiver operating characteristic curves (AUCROC) and calibration.

RESULTS

HA-AKI incidence within 7 days (kidney disease: improving global outcomes (KDIGO) change in SCr) was 8.1% (n=409) of medical patients with known baseline SCr, 6.6% (n=141) in those without a baseline, 4.9% (n=204) in surgical patients with baseline and 4% (n=49) in those without. Across the four cohorts AUCROC were: medical with known baseline 0.65 (95% CIs 0.62 to 0.67) and no baseline 0.71 (0.67 to 0.75), surgical with baseline 0.66 (0.62 to 0.70) and no baseline 0.68 (0.58 to 0.75). For calibration, in medicine and surgical cohorts with baseline SCr, Hosmer-Lemeshow p values were non-significant, suggesting acceptable calibration. In the medical cohort, at a cut-off of five points on the APS to predict HA-AKI, positive predictive value was 16% (13-18%) and negative predictive value 94% (93-94%). Of medical patients with HA-AKI, those with an APS ≥5 had a significantly increased risk of death (28% vs 18%, OR 1.8 (95% CI 1.1 to 2.9), p=0.015).

CONCLUSIONS

On external validation the APS on admission shows moderate discrimination and acceptable calibration to predict HA-AKI and may be useful as a severity marker when HA-AKI occurs. Harnessing linked data from primary care may be one way to achieve more accurate risk prediction.

Contrast-Induced Acute Kidney Injury: An Update

Contrast-induced acute kidney injury (CI-AKI) is defined as an abrupt deterioration in renal function associated with the administration of iodinated contrast media. This type of acute kidney injury is frequently encountered as a complication of percutaneous coronary intervention (PCI) and is associated with adverse short- and long-term outcomes including mainly mortality, cardiovascular morbidity and prolongation of hospitalization. The incidence of CI-AKI after PCI ranges from 2 to 20 % according to baseline kidney function. It may also range according to the clinical setting, being higher after emergency PCI. The primary manifestation is a small decline in kidney function, occurring 1 to 3 days after the procedure. Kidney function usually returns to preexisting levels within 7 days. Incidence of acute renal failure requiring dialysis following PCI is rare (<1 %). The present article aims to review up-to-date published data concerning diagnosis, definition, epidemiology and prognosis of this novel in-hospital epidemic.

Preprocedural Prediction Model for Contrast-Induced Nephropathy Patients

Background

Several models have been developed for prediction of contrast‐induced nephropathy (CIN); however, they only contain patients receiving intra‐arterial contrast media for coronary angiographic procedures, which represent a small proportion of all contrast procedures. In addition, most of them evaluate radiological interventional procedure‐related variables. So it is necessary for us to develop a model for prediction of CIN before radiological procedures among patients administered contrast media.

Methods and Results

A total of 8800 patients undergoing contrast administration were randomly assigned in a 4:1 ratio to development and validation data sets. CIN was defined as an increase of 25% and/or 0.5 mg/dL in serum creatinine within 72 hours above the baseline value. Preprocedural clinical variables were used to develop the prediction model from the training data set by the machine learning method of random forest, and 5‐fold cross‐validation was used to evaluate the prediction accuracies of the model. Finally we tested this model in the validation data set. The incidence of CIN was 13.38%. We built a prediction model with 13 preprocedural variables selected from 83 variables. The model obtained an area under the receiver‐operating characteristic (ROC) curve (AUC) of 0.907 and gave prediction accuracy of 80.8%, sensitivity of 82.7%, specificity of 78.8%, and Matthews correlation coefficient of 61.5%. For the first time, 3 new factors are included in the model: the decreased sodium concentration, the INR value, and the preprocedural glucose level.

Conclusions

The newly established model shows excellent predictive ability of CIN development and thereby provides preventative measures for CIN.

Risk Prediction Models for Contrast-Induced Acute Kidney Injury Accompanying Cardiac Catheterization: Systematic Review and Meta-analysis

BACKGROUND

Identification of patients at risk of contrast-induced acute kidney injury (CI-AKI) is valuable for targeted prevention strategies accompanying cardiac catheterization.

METHODS

We searched MedLine and EMBASE for articles that developed or validated a clinical prediction model for CI-AKI or dialysis after angiography or percutaneous coronary intervention. Random effects meta-analysis was used to pool c-statistics of models. Heterogeneity was explored using stratified analyses and meta-regression.

RESULTS

We identified 75 articles describing 74 models predicting CI-AKI, 10 predicting CI-AKI and dialysis, and 1 predicting dialysis. Sixty-three developed a new risk model whereas 20 articles reported external validation of previously developed models. Thirty models included sufficient information to obtain individual patient risk estimates; 9 using only preprocedure variables whereas 21 included preprocedural and postprocedure variables. There was heterogeneity in the discrimination of CI-AKI prediction models (median [total range] in c-statistic 0.78 [0.57-0.95]; I² = 95.8%, Cochran Q-statistic P < 0.001). However, there was no difference in the discrimination of models using only preprocedure variables compared with models that included postprocedural variables (P = 0.868). Models predicting dialysis had good discrimination without heterogeneity (median [total range] c-statistic: 0.88 [0.87-0.89]; I² = 0.0%, Cochran Q-statistic P = 0.981). Seven prediction models were externally validated; however, 2 of these models showed heterogeneous discriminative performance and 2 others lacked information on calibration in external cohorts.

CONCLUSIONS

Three published models were identified that produced generalizable risk estimates for predicting CI-AKI. Further research is needed to evaluate the effect of their implementation in clinical care.

A New Preprocedure Risk Score for Predicting Contrast-Induced Acute Kidney Injury

BACKGROUND

Most of the risk models for predicting contrast-induced acute kidney injury (CI-AKI) are available for only postcontrast exposure prediction; however, prediction before the procedure is more valuable in practice. This study aimed to develop a risk scoring system based on preprocedural characteristics for early prediction of CI-AKI in patients after coronary angiography or percutaneous coronary intervention (PCI).

METHODS

We prospectively recruited 1777 consecutive patients who were randomized in an approximate 3:2 ratio to create a development data set (n = 1076) and a validation data set (n = 701). A risk score model based on preprocedural risk factors was developed using stepwise logistic regression. Validation was performed by bootstrap and split-sample methods.

RESULTS

The occurrence of CI-AKI was 5.97% (106 of 1777), 5.95% (64 of 1076), and 5.99% (42 of 701) in the overall, developmental, and validation data sets, respectively. The risk score was developed with 5 prognostic factors (age, serum creatinine levels, N-terminal pro b-type natriuretic peptide levels, high-sensitivity C-reactive protein, and primary PCI), ranged from 0-36, and was well calibrated (Hosmer-Lemeshow χ² = 4.162; P = 0.842). Good discrimination was obtained both in the developmental and validation data sets (C-statistic, 0.809 and 0.798, respectively). The risk score was highly and positively associated with CI-AKI (P for trend < 0.001) in-hospital and long-term outcomes.

CONCLUSIONS

The novel risk score model we developed is a simple and accurate tool for early/preprocedural prediction of CI-AKI in patients undergoing coronary angiography or PCI. This tool allows assessment of the risk of CI-AKI before contrast exposure, allowing for timely initiation of appropriate preventive measures.

Prediction Models and Their External Validation Studies for Mortality of Patients with Acute Kidney Injury: A Systematic Review

OBJECTIVES

To systematically review AKI outcome prediction models and their external validation studies, to describe the discrepancy of reported accuracy between the results of internal and external validations, and to identify variables frequently included in the prediction models.

METHODS

We searched the MEDLINE and Web of Science electronic databases (until January 2016). Studies were eligible if they derived a model to predict mortality of AKI patients or externally validated at least one of the prediction models, and presented area under the receiver-operator characteristic curves (AUROC) to assess model discrimination. Studies were excluded if they described only results of logistic regression without reporting a scoring system, or if a prediction model was generated from a specific cohort.

RESULTS

A total of 2204 potentially relevant articles were found and screened, of which 12 articles reporting original prediction models for hospital mortality in AKI patients and nine articles assessing external validation were selected. Among the 21 studies for AKI prediction models and their external validation, 12 were single-center (57%), and only three included more than 1,000 patients (14%). The definition of AKI was not uniform and none used recently published consensus criteria for AKI. Although good performance was reported in their internal validation, most of the prediction models had poor discrimination with an AUROC below 0.7 in the external validation studies. There were 10 common non-renal variables that were reported in more than three prediction models: mechanical ventilation, age, gender, hypotension, liver failure, oliguria, sepsis/septic shock, low albumin, consciousness and low platelet count.

CONCLUSIONS

Information in this systematic review should be useful for future prediction model derivation by providing potential candidate predictors, and for future external validation by listing up the published prediction models.

Perioperative Cardiovascular Evaluation for Orthotopic Liver Transplantation

Patients with advanced liver disease have a high prevalence of cardiovascular risk factors, but many of them are asymptomatic. Cardiovascular risk stratification prior to liver transplant can be done by dobutamine stress echocardiography, stress myocardial perfusion imaging, cardiac computer tomography, and coronary angiography, but there are no clear recommendations regarding what method should be used and who should be screened. Because of this and because of inherent risk profile in this population, the variations in practice are significant. Careful screening and rigorous management of cardiovascular risk factors are important to ensure optimal cardiovascular outcomes in the immediate post-transplantation period and in the long term as well.

Crucial Roles of Systemic and Tissue Lipid Peroxidation Levels and Anti-Oxidant Defences Following Contrast Agent Application

Background

One of the most important side effects of contrast pharmaceutical agents, which are used very common in routine radiology practice, is contrast induced nephropathy. Even ischemia, oxidative stress and osmolality related cytotoxic effects are considered, the molecular mechanisms underlying this pathology have not been identified completely yet.

Objectives

The aim of the current study was to reveal the role of oxidative stress and antioxidant enzymatic defence mechanisms in the aetiopathogenesis of contrast-induced nephropathy. We also studied possible alleviating effects of N-acetylcysteine (NAC), a potent antioxidant, to obtain extra information regarding the molecular mechanisms underlying this pathology.

Materials and Methods

This is an clinical-experimental study, This study was conducted of Istanbul/Turkey between September 15, 2012 and April 15, 2013. Three groups of male rats were randomly set up as a control group (C), a 100 mg/kg intraperitoneal NAC + 7 mL/kg contrast agent group (N + CIN) and a 7 mL/kg intraperitoneal contrast agent group (CIN). They were placed in individual metabolic cages 48 hours after agent administration to obtain 24-hour urine samples. Renal function tests (albumin, urea, creatinine, total protein) were conducted, oxidative stress parameters (Cu, Zn superoxide dismutase activity - Cu, Zn-SOD; advanced oxidation protein products - AOPP; protein carbonyls - PCO; total thiol groups - T-SH; and lipid hydroperoxides -LHP) were measured and tissues were analysed histopathologically.

Results

Compared with the control group, groups CIN and N + CIN had significantly higher urea and LHP levels (P < 0.05 and P < 0.001, respectively) and significantly lower Cu, Zn-SOD activity and creatinine clearance (P < 0.05). There was no statistically significant difference between the groups in PCO or AOPP levels despite differences in descriptive statistics.

Conclusions

Contrast-agent-induced nephropathic changes are more closely related to the magnitude of lipid peroxidation than protein oxidation.

Monochromatic Spectral Computed Tomography with Low Iodine Concentration Contrast Medium in a Rabbit VX2 Liver Model:: Investigation of Image Quality and Detection Rate

RATIONALE AND OBJECTIVES

This study aimed to validate the feasibility of using virtual monochromatic spectral computed tomography (CT) with isotonic low iodine concentration contrast medium for VX2 hepatic tumors.

MATERIALS AND METHODS

Sixty New Zealand white rabbits with implanted VX2 hepatic tumors underwent two-phase contrast-enhanced spectral CT imaging on the 14th day after tumor implantation. They were randomly divided into groups A, B, and C, with 20 rabbits each (group A: 270 mg I/mL, monochromatic spectral images; group B: 370 mg I/mL, conventional 120 kVp images, 100% filtered back projection [FBP]; group C: 270 mg I/mL, conventional 120 kVp images, 100% FBP). Group A was further divided into two subgroups (subgroup A1: 100% FBP; subgroup A2: 50% FBP + 50% adaptive statistical iterative reconstruction). Objective evaluation (signal-to-noise ratio [SNR], contrast-to-noise ratio [CNR], and image noise), subjective rating score (image noise score, anatomical details score, overall image quality score, and lesion conspicuity score), CT dose index volume, and dose length product were compared between groups during two-phase contrast enhancement. The detection rates of the four groups were calculated as percentages.

RESULTS

Image noise (SNR and CNR) among the four groups was statistically significant (P <0.05). The image noise in group A2 was lower than in group A1, but higher than that in groups B and C (P <0.05). SNR and CNR in group A2 were the highest, followed by group A1, and group C was the lowest (P <0.05 for all). The image noise score of group A2 was higher than that of the other three groups. In terms of the anatomic details score, the overall image quality score, and the lesion conspicuity score, the images of group A2 were superior to that of groups A1 and C. For hepatic tumor diameters more than or equal to 1.0 cm and less than 3.0 cm, group A achieved a higher detection rate than groups B and C. The CT dose index volume, dose length product, and effective dose in group A were significantly lower than that in groups B and C (P <0.05). On average, group A reduced the effective radiation dose by 27.2% compared to group B, whereas group B reduced the effective radiation dose by 28% compared to group C. Group A reduced the iodine load by 22.86% compared to group B.

CONCLUSIONS

The use of monochromatic images combined with 50% adaptive statistical iterative reconstruction with an isotonic low concentration contrast medium of 270 mg I/mL can optimize image quality, reduce image noise, increase detection rate for small tumors, and decrease radiation dose and iodine load in hepatic tumor CT examinations.

Impact of Iodinated Contrast on Renal Function and Hemodynamics in Rats with Chronic Hyperglycemia and Chronic Kidney Disease

Iodinated contrast (IC) is clinically used in diagnostic and interventional procedures, but its use can result in contrast-induced acute kidney injury (CI-AKI). Chronic kidney disease (CKD) and chronic hyperglycemia (CH) are important predisposing factors to CI-AKI. The aim of this study was to investigate the impact of iodinated contrast on the renal function and hemodynamics in rats with chronic hyperglycemia and chronic kidney disease. A total of 30 rats were divided into six groups; Sham: control of chronic renal disease; Citrate: control of chronic hyperglycemia (CH); Nx5/6: rats with 5/6 nephrectomy; Chronic Hyperglycemia: rats receiving Streptozotocin 65 mg/kg; Nx5/6 + IC: rats Nx5/6 received 6 mL/kg of IC; CH + IC: Chronic hyperglycemia rats receiving 6 mL/kg of IC. Renal function (inulin clearance; urinary neutrophil gelatinase-associated lipocalin, NGAL) and hemodynamics (arterial blood pressure; renal blood flow; renal vascular resistance) were evaluated. Iodinated contrast significantly increased urinary NGAL and reduced inulin clearance, while the hemodynamics parameters showed changes in arterial blood pressure, renal blood flow, and renal vascular resistance in both CKD and CH groups. The results suggest that the iodinated contrast in risk factors models has important impact on renal function and hemodynamics. NGAL was confirmed to play a role of highlight in diagnosis of CI-AKI.

Preventive effect of oral nicorandil on contrast-induced nephropathy in patients with renal insufficiency undergoing elective cardiac catheterization

This study aims to investigate the preventive effect of oral nicorandil on contrast-induced nephropathy (CIN) in patients with renal insufficiency undergoing elective cardiac catheterization. A total of 240 patients with an estimated glomerular filtration rate (eGFR) of 60 mL/min or less, who were undergoing elective cardiac catheterization, were randomly assigned to nicorandil group (n = 120, 10 mg nicorandil, three times daily from 2 days before to 3 days after procedure) or control group (n = 120, matching placebo as the same method). The primary endpoint was the incidence of CIN defined as 25 % increase in serum creatinine (SCr) from baseline or 44 μmol/L (0.5 mg/dL) increase in absolute value within 72 h after exposure to contrast medium. The secondary endpoints were: (1) the changes of SCr, Cystatin-C (Cys-C) and eGFR within 72 h; (2) major adverse events (MACE) occurring within 30 days. Baseline characteristics of the patients in the two groups were similar. The incidence of CIN was significantly lower in nicorandil group compared with control group (6.67 vs. 17.5 %, P = 0.017). Compared with the control group, nicorandil group tended to have a lower SCr and Cys-C levels as well as a higher eGFR at 48 h after the procedure (all P < 0.05). There was no difference about the incidence of MACE within 30 days between nicorandil group and control group (4.16 vs. 5.83 %, P = 0.767). Multivariate logistic analysis showed that nicorandil was an independent protective factor against CIN (OR = 0.260, 95 % CI = 0.1-0.676, P = 0.006). Therefore, we concluded that oral nicorandil was associated with a decline in the incidence of CIN in patients with renal insufficiency undergoing elective cardiac catheterization.

Impact of deteriorated calcium-phosphate homeostasis on amputation-free survival after endovascular revascularization in patients with critical limb ischemia on hemodialysis

Patients on hemodialysis (HD) have abnormalities of calcium-phosphate (CaP) homeostasis and high CaP product contributes to atherosclerosis pathogenesis and adverse events. Patients on HD with critical limb ischemia (CLI) are at risk for major amputation and death because of advanced systemic atherosclerotic disease. The aim of this study was to evaluate the relationship between CaP product and amputation-free survival (AFS) in CLI after endovascular treatment (EVT). We retrospectively analyzed 221 CLI patients on HD. In Kaplan–Meier analysis, AFS was significantly lower in patients with CaP product ⩾55 mg2/dL2 compared to those with CaP product <55 mg2/dL2 (54.3% vs 78.5%, p = 0.002). However, neither serum phosphate nor calcium levels were individually associated with AFS. In multivariate analysis, CaP product ⩾55 mg2/dL2 was an independent predictor for AFS in CLI patients on HD (hazard ratio, 3.03; 95% confidence interval, 1.78–5.15; p-value <0.001). We concluded abnormal CaP homeostasis was associated with lower AFS after EVT in CLI patients on HD, and can serve for their risk stratification.