Iodixanol Versus Low-Osmolar Contrast Media for Prevention of Contrast Induced Nephropathy

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

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

Contrast removal from coronary sinus for prevention of contrast-induced nephropathy: a review

The occurrence of contrast-induced-nephropathy (CIN) is related to the amount of contrast administration. Any removal of contrast from systemic circulation before reaching the kidneys might be beneficial using a device that removes contrast from a coronary sinus (CS). This manuscript aims to review the available literature regarding contrast removal from CS during coronary angiography or intervention for the prevention of CIN.

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

BACKGROUND

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

METHODS

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

RESULTS

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

CONCLUSION

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

3D-Printed Radiopaque Bioresorbable Stents to Improve Device Visualization

Bioresorbable stents (BRS) hold great promise for the treatment of many life-threatening luminal diseases. Tracking and monitoring of stents in vivo is critical for avoiding their malposition and inadequate expansion, which often leads to complications and stent failure. However, obtaining high X-ray visibility of polymeric BRS has been challenging because of their intrinsic radiolucency. This study demonstrates the use of photopolymerization-based 3D printing technique to fabricate radiopaque BRS by incorporating iodixanol, a clinical contrast agent, into a bioresorbable citrate-based polymer ink. The successful volumetric dispersion of the iodixanol through the 3D-printing process confers strong X-ray visibility of the produced BRS. Following in vitro degradation, the 3D-printed BRS embedded in chicken muscle maintains high X-ray visibility for at least 4 weeks. Importantly, the 3D-printed radiopaque BRS demonstrates good cytocompatibility and strong mechanical competence in crimping and expansion, which is essential for minimally invasive stent deployment. In addition, it is found that higher loading concentrations of iodixanol, e.g. 10 wt.%, results in more strut fractures in stent crimping and expansion. To conclude, this study introduces a facile strategy to fabricate radiopaque BRS through the incorporation of iodixanol in the 3D printing process, which could potentially increase the clinical success of BRS.

Iso-osmolar versus low-osmolar contrast media and outcomes after percutaneous coronary intervention: Insights from the VA CART Program

OBJECTIVES

To assess whether contrast media type is associated with outcomes in veterans undergoing percutaneous coronary intervention (PCI).

BACKGROUND

There is uncertainty about the impact of iso-osmolar contrast medium (IOCM) versus low-osmolar contrast medium (LOCM) on acute kidney injury (AKI) and other major adverse renal or cardiovascular events (MARCE) after PCI. We assessed the association between contrast media type and MARCE in patients who underwent PCI within the Veterans Administration Healthcare System.

METHODS

We reviewed PCIs performed between 2009 and 2019 using data from the Veterans Affairs Clinical Assessment, Reporting, and Tracking Program. The primary endpoint was MARCE, a composite of myocardial infarction, stroke, all-cause death, AKI, and dialysis onset at 30 days.

RESULTS

The analysis cohort consisted of 50,389 patients of whom 25,555 received LOCM and 24,834 received IOCM. There was significant variation in contrast type across sites. After adjustment for comorbidities, no significant association between contrast media type and MARCE was observed in both site-unadjusted (odds ratio [OR] for IOCM: 0.99; 95% confidence interval [CI]: 0.92-1.08; p = 0.97) and site-adjusted (OR: 1.06; 95% CI: 0.95-1.18; p = 0.30) analyses. Similar results were obtained when contrast volume was imputed or the data was subset to individuals with available contrast volume.

CONCLUSION

In a large cohort of veterans undergoing PCI, we found considerable site variation in the type of contrast media used but no significant association between contrast media type and the incidence of MARCE, both before and after adjustment for the site.

Three-Dimensional Kidney-on-a-Chip Assessment of Contrast-Induced Kidney Injury: Osmolality and Viscosity

Increased viscosity of concentrated contrast media (CM) in the renal tubules can perturb renal hemodynamics and have a detrimental effect on tubular epithelial cells. However, the effects of viscosity on contrast-induced nephropathy (CIN) remain poorly understood. Conventional in vitro culture studies do not reflect the rheological properties of CM. Therefore, we investigated the effects of CM viscosity on renal tubules using a kidney-on-a-chip and two different types of CM. Renal proximal tubule epithelial cells (RPTEC) were cultured in a three-dimensional microfluidic culture platform under bidirectional fluid shear stress. We treated the RPTEC with two types of CM: low- (LOCM, iopromide) and iso-osmolar contrast media (IOCM, iodixanol). Renal tubular cell injury induced by LOCM and IOCM was examined under different iodine concentrations (50–250 mgI/mL) and shear-stress conditions. LOCM showed a significant dose-dependent cytotoxic effect, which was significantly higher than that of IOCM under static and low-to-moderate shear stress conditions. However, high shear-stress resulted in reduced cell viability in IOCM; no difference between IOCM and LOCM was found under high shear-stress conditions. The cytotoxic effects were pronounced at a mean shear stress of 1 dyn/cm2 or higher. The high viscosity of IOCM slowed the fluid flow rate and augmented fluid shear-stress. We suggest an alternative in vitro model of CIN using the three-dimensional kidney-on-a-chip. Our results indicate a vital role of viscosity-induced nephrotoxicity under high shear-stress conditions, contrary to the findings of conventional in vitro studies.

Comparative analysis of four established risk scores for predicting contrast induced acute kidney injury after primary percutaneous coronary interventions

Objectives

 This study aimed to compare Mehran Risk Score (MRS) with three well -known scoring systems namely CHA₂DS₂-VASc score, Canada Acute Coronary Syndrome Risk Score (C-ACS), and Thrombolysis in Myocardial Infarction risk index (TRI) to predict the contrast-induced acute kidney injury (CI-AKI) after primary percutaneous coronary intervention (PCI).

Background

CI-AKI is a common complication after primary PCI associated with an adverse prognosis.

Methods

In this study consecutive patients of primary PCI were included. Patients with chronic kidney diseases, exposure to the contrast medium within the past 7 days, and Killip class IV at presentation were excluded. MRS along with three risk scores namely CHA₂DS₂-VASc, C-ACS, and TRI were calculated for all patients and CI-AKI was defined as either 0.5 mg/dL or 25% relative increase in post-procedure serum creatinine. The area under the curve (AUC) curve was reported.

Results

Post primary PCI CI-AKI was observed in 63 (9.1%) patients out of 691 patients. The AUC was 0.745 [0.679-0.810] for MRS, 0.725 [0.662-0.788] for CHA₂DS₂-VASc, 0.671 [0.593-0.749] for C-ACS, and 0.734 [0.674-0.795] for TRI. Sensitivity and specificity were 61.9% [48.8-73.8%] and 76.0% [72.4-79.3%] for MRS ≥ 6.5, 66.7% [53.7-78.0%] and 66.7% [62.9-70.4%] for CHA₂DS₂-VASc ≥ 2, 52.4% [39.4-65.1%] and 79.9% [76.6-83.0%] for C-ACS ≥ 1, and 87.3% [76.5-94.4%] and 49.2% [45.2-53.2%] for TRI ≥ 16 respectively.

Conclusions

The MRS has shown higher discriminating power than CHA₂DS₂-VASc, C-ACS, and TRI. However, the TRI can be of good value in clinical practice due to its simplicity and high sensitivity in detecting patients at higher risk of CI-AKI after primary PCI.

SCAI expert consensus update on best practices in the cardiac catheterization laboratory: This statement was endorsed by the American College of Cardiology (ACC), the American Heart Association (AHA), and the Heart Rhythm Society (HRS) in April 2021

The current document commissioned by the Society for Cardiovascular Angiography and Interventions (SCAI) and endorsed by the American College of Cardiology, the American Heart Association, and Heart Rhythm Society represents a comprehensive update to the 2012 and 2016 consensus documents on patient-centered best practices in the cardiac catheterization laboratory. Comprising updates to staffing and credentialing, as well as evidence-based updates to the pre-, intra-, and post-procedural logistics, clinical standards and patient flow, the document also includes an expanded section on CCL governance, administration, and approach to quality metrics. This update also acknowledges the collaboration with various specialties, including discussion of the heart team approach to management, and working with electrophysiology colleagues in particular. It is hoped that this document will be utilized by hospitals, health systems, as well as regulatory bodies involved in assuring and maintaining quality, safety, efficiency, and cost-effectiveness of patient throughput in this high volume area.

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.

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.

Anti-Apoptotic and Antioxidant Effects of 3-Epi-Iso-Seco-Tanapartholide Isolated from Artemisia Argyi Against Iodixanol-Induced Kidney Epithelial Cell Death

Iodixanol is a non-ionic iso-osmolar contrast agent, but it is a risk factor for kidney damage and increases morbidity and mortality. In this study, we investigated the effect of 9 sesquiterpenes isolated from mugwort (Artemisia argyi) in contrast agent-induced cytotoxicity in LLC-PK1 cells. Cells were exposed to nine sesquiterpene compounds for 2 h, followed by incubation with iodixanol for 3 h. Cell viability was assessed using the Ez-Cytox assay. The level of reactive oxygen species was measured using 2′,7′-dichlorodihydrofluorescein diacetate staining. Apoptotic cell death was detected using annexin V/PI staining. In addition, immunofluorescence staining and western blotting were performed using antibodies against proteins related to apoptosis, oxidative stress, and MAPK pathways. The most effective 3-epi-iso-seco-tanapartholide (compound 8) among the 9 sesquiterpene compounds protected LLC-PK1 cells from iodixanol-induced cytotoxicity, oxidative stress, and apoptotic cell death. Pretreatment with compound 8 reversed iodixanol-induced increases in the expression of JNK, ERK, p38, Bax, caspase-3, and caspase-9. It also reversed the iodixanol-induced decrease in Bcl-2 expression. Furthermore, pretreatment with compound 8 caused nuclear translocation of Nrf2 and upregulated HO-1 via the Nrf2 pathway in iodixanol-treated LLC-PK1 cells. Thus, we demonstrated here that compound 8 isolated from A. argyi has the potential to effectively prevent iodixanol-induced kidney epithelial cell death via the caspase-3/MAPK pathways and HO-1 via the Nrf2 pathway.

DDAH-2 alleviates contrast medium iopromide-induced acute kidney injury through nitric oxide synthase

BACKGROUND

Contrast medium-induced acute kidney injury (CI-AKI) is one of the most common causes of hospital-acquired acute renal failure. However, the pathogenesis of CI-AKI remains unclear. Asymmetric dimethylarginine (ADMA) is an endogenous nitric oxide synthase (NOS) inhibitor that is largely metabolised by dimethylarginine dimethylaminohydroxylase (DDAH) in humans. Two isoforms of DDAH exist, namely, DDAH-1 and DDAH-2. In the present study, we examined whether the DDAH-2/ADMA/NOS pathway is involved in the pathogenesis of CI-AKI.

METHODS AND RESULTS

Exposure to the contrast medium iopromide led to increase in creatinine and blood urea nitrogen (BUN) levels, accumulation of ADMA, increase in reactive oxygen species (ROS) generation, and an inflammatory response in mice kidney tissue. The injection of adenovirus-harbouring DDAH-2 lowered renal ADMA levels and had a reno-protective effect against contrast-medium injury by decreasing cell apoptosis, ROS, and fibrosis. By contrast, contrast medium-induced renal injury was exacerbated in heterozygous DDAH-2 knockout mice. In the in vitro study, overexpression of DDAH-2 increased the levels of nitrite and intracellular cGMP, while the DDAH-2 knockdown induced the opposite effect. These findings were also observed in the in vivo sample.

CONCLUSIONS

Our findings provide the first evidence that the DDAH-2/ADMA/NOS pathway is involved in the pathogenesis of CI-AKI and that the protective effect of DDAH-2 probably arises from the modulation of NOS activity, oxidative stress, and the inflammatory process.

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.

Neutrophil Gelatinase-Associated Lipocalin for the Early Prediction of Acute Kidney Injury in ST-Segment Elevation Myocardial Infarction Patients Treated with Primary Percutaneous Coronary Intervention

INTRODUCTION AND OBJECTIVE

Neutrophil gelatinase-associated lipocalin (NGAL), a glycoprotein released by renal tubular cells, can be used as a marker of early tubular damage. We evaluated plasma NGAL level utilization for the identification of acute kidney injury (AKI) among ST-elevation myocardial infarction (STEMI) patients undergoing primary coronary intervention (PCI).

METHODS

131 STEMI patients treated with PCI were prospectively included. Plasma NGAL levels were drawn prior to PCI (0 h) and 24 h afterwards. AKI was defined per KDIGO criteria of serum creatinine increase. Receiver-operating characteristic (ROC) methods were used to identify optimal sensitivity and specificity for the observed NGAL range.

RESULTS

Overall AKI incidence was 14%. NGAL levels were significantly higher for patients with AKI at both 0 h (164 ± 42 vs. 95 ± 30; p < 0.001) and 24 h (142 ± 41 vs. 93 ± 36; p < 0.001). Per ROC curve analysis, an optimal cutoff value of NGAL (>120 ng/mL) predicted AKI with 80% sensitivity and specificity (AUC 0.881, 95%, CI 0.801-0.961, p < 0.001). In a multivariate logistic regression model, NGAL levels were independently associated with AKI at 0 h (OR 1.044, 95% CI 1.013-1.076; p = 0.005) and 24 h (OR 1.018, 95% CI 1.001-1.036; p = 0.04).

CONCLUSIONS

Elevated NGAL levels, suggesting renal tubular damage, are independently associated with AKI in STEMI patients undergoing primary PCI.

The optimal monoenergetic spectral image level of coronary computed tomography (CT) angiography on a dual-layer spectral detector CT with half-dose contrast media

Background

To investigate the optimal monoenergetic level of spectral reconstructions in coronary computed tomography angiography (coronary CTA) on a dual-layer spectral detector computed tomography (SDCT) with half-dose contrast media.

Methods

Two hundred patients with suspected coronary artery disease (CAD) were enrolled in this prospective coronary CTA study and randomly divided into a routine-dose contrast media group and a half-dose contrast media group (each n=100). Coronary CTA was performed using SDCT with prospective electrocardiogram (ECG)-gated mode. A tube voltage of 120 kVp was used, along with an automated tube current modulation. A dose of iodixanol 270 mgI/mL of 0.8 and 0.4 mL/kg was administered to the routine and half-dose groups, respectively. For the routine-dose group, 120 kVp polychromatic images with a model-based iterative reconstruction (IMR) (Group A) were reconstructed. For the half-dose group, three monoenergetic levels of images were reconstructed (Group B, 45 keV; Group C, 50 keV; and Group D, 55 keV). Objective indicators [mean CT values; noise; signal-to-noise ratio (SNR); and contrast-to-noise ratio (CNR)] and subjective indicators (contrast, sharpness, subjective noise, and acceptability) in each group were compared.

Results

There were no significant differences in demographics or radiation dose (1.83±0.51 vs. 1.80±0.53 mSv, P=0.78) between the routine- and half-dose groups. The average iodine loads were 15.33±2.26 and 7.48±1.14 g, respectively. Mean CT values, SNR, CNR, and subjective contrast in Group C were higher than those in Group A (P<0.05), and there were no significant differences in other indicators between Group C and Group A (P>0.05). The objective and subjective noise in Group B were worse than those in Group A (P<0.05). The contrast, sharpness, and acceptability of Group D were all worse than those of Group A (P<0.05).

Conclusions

Compared to routine polychromatic images, 50 keV monoenergetic images can provide equivalent or improved coronary image quality in coronary CTA performed on SDCT with half the amount of contrast media.

Post-contrast acute kidney injury in a hospitalized population: short-, mid-, and long-term outcome and risk factors for adverse events

Objectives

To investigate the prognosis including major adverse kidney events within 30 days (MAKE30) and 90-day and 1-year adverse outcome in hospitalized patients with post-contrast acute kidney injury (PC-AKI) to identify high-risk factors.

Methods

This retrospective observational study included 288 PC-AKI patients selected from 277,898 patients admitted to hospitals from January 2015 to December 2015. PC-AKI was defined according to the 2018 guideline of European Society of Urogenital Radiology. Multivariable Cox regression and logistic regression analyses were used to analyze main outcome and risk factors.

Results

PC-AKI patients with AKI stage ≥ 2 had much higher incidence of MAKE30 than those with AKI stage 1 (RR = 7.027, 95% CI 4.918–10.039). Persistent renal dysfunction, heart failure, central nervous system failure, baseline eGFR < 60 mL/min/1.73 m², oliguria or anuria, blood urea nitrogen ≥ 7.14 mmol/L, respiratory failure, and shock were independent risk factors of 90-day or 1-year adverse prognosis (p < 0.05). Compared with transient renal dysfunction, PC-AKI patients with persistent renal dysfunction had a higher all-cause mortality rate (RR = 3.768, 95% CI 1.612–8.810; RR = 4.106, 95% CI 1.765–9.551) as well as combined endpoints of death, chronic kidney disease, or end-stage renal disease (OR = 3.685, 95% CI 1.628–8.340; OR = 5.209, 95% CI 1.730–15.681) within 90 days or 1 year.

Conclusions

PC-AKI is not always a transient, benign creatininopathy, but can result in adverse outcome. AKI stage is independently correlated to MAKE30 and persistent renal dysfunction may exaggerate the risk of long-term adverse events.

Key Points

• PC-AKI can result in adverse outcome such as persistent renal dysfunction, dialysis, chronic kidney disease (CKD), end-stage renal disease (ESRD), or death.

• AKI stage is independently correlated to MAKE30.

• Persistent renal dysfunction may exaggerate the risk of long-term adverse events.

Electronic supplementary material

The online version of this article (10.1007/s00330-020-06690-3) contains supplementary material, which is available to authorized users.

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.

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.

Routine iso-osmolar contrast media use and acute kidney injury following percutaneous coronary intervention for ST elevation myocardial infarction

BACKGROUND

Temporal changes in contrast-induced acute kidney injury (CI-AKI) incidence following primary percutaneous coronary intervention (PPCI) are poorly defined. Additionally, the benefits of iso-osmolar contrast media (IOCM) compared to low osmolar CM (LOCM) are uncertain.

METHODS

Using data from a regional PPCI service, temporal changes in baseline risk and annual incidence of CI-AKI were studied. A CM protocol change occurred in 2013 allowing a comparison of the incidence of CI-AKI between LOCM (2012-13) and IOCM (2013-15).

RESULTS

Between 2012 and 2015, 208 of 1310 patients experienced CI-AKI (15.9%). The Mehran AKI risk score did not change during the study period although there was an increase in the incidence of CI-AKI in later study years (P<0.001 for trend) when IOCM was used. Factors independently associated with CI-AKI were IOCM use (OR=1.96, [95% CI: 1.39-2.75]), age per year (OR=1.02, 95% CI: 1.01-1.04), baseline creatinine per µmol/L (OR=1.006, 95% CI: 1.003-1.01) and contrast volume per milliliter (OR=1.002, 95% CI: 1.001-1.004). The baseline characteristics of patients treated using IOCM (N.=783) vs. LOCM (N.=527) were similar (Mehran Score 6.6 vs. 6.9, P=0.173) but CI-AKI occurred more frequently with IOCM compared to LOCM (19.2% vs. 11.2%, P<0.001). Use of IOCM was independently associated with CI-AKI (OR=1.98, 95% CI: 1.339-2.774, P<0.001) with consistency across all sub-groups of age, gender, baseline creatinine, contrast volume, shock and diabetes. The adjusted in-hospital mortality was increased with IOCM compared to LOCM (OR=3.03, 95% CI: 1.313-6.994, P=0.009).

CONCLUSIONS

IOCM use was observed to be associated with an increased occurrence of CI-AKI, and an increase in in-hospital mortality after primary PCI.

Comparison between rosuvastatin and atorvastatin for the prevention of contrast-induced nephropathy in patients with STEMI undergoing primary percutaneous coronary intervention

Introduction: There is some controversy over the efficacy of statins for the prevention of contrastinduced nephropathy (CIN). There have also been reports on varying efficacies of different statins. Hence, in this study the efficacy of atorvastatin and rosuvastatin for the prevention of CIN was assessed.

Methods: This single-blind randomized clinical trial was performed on 495 random patients with myocardial infarction with ST-segment elevation undergoing primary percutaneous coronary intervention (PCI) in a training referral hospital in 2015. Patients were randomly assigned to receive either atorvastatin 80 mg at admission and daily or rosuvastatin 40 mg at admission and daily. CIN was defined based on serum creatinine elevation after 48 hours from the PCI.

Results: The incidence of CIN was observed in 63 patients (21.4%) After 48 hours from primary PCI. Of those, 17% (n = 50) were grade 1 CIN, while 4.4% (n = 13) were grade 2 CIN. There was no significant difference between rosuvastatin group compared with atorvastatin group, regarding the CIN grading (P = 0.14).

Conclusion: Our results indicate that atorvastatin and rosuvastatin have similar efficacy for the prevention of CIN.

Iodixanol versus iopromide in patients with renal insufficiency undergoing coronary angiography with or without PCI

BACKGROUND

The use of contrast agents during coronary angiography can result in contrast-induced nephropathy (CIN), particularly in patients with renal dysfunction. On the contrary, different contrast agents can induce different degree of changes in cardiac function. The objective of our meta-analysis was to compare the clinical safety of iso-osmolar contrast medium iodixanol to low-osmolar contrast medium iopromide in patients with renal insufficiency undergoing coronary angiography with or without percutaneous coronary intervention (PCI).

METHODS

We searched Medline, Embase, Cochrane Library, and reference lists to identify randomized controlled trials that compared iodixanol to iopromide with the incidence of CIN as an endpoint in renal impaired patients undergoing coronary angiography. Outcome measures were the incidence of CIN, absolute peak serum creatinine (Scr) increase from baseline and a composite of cardiovascular adverse events.

RESULTS

A total of 8 trials with 3532 patients were pooled; 1759 patients received iodixanol and 1773 patients received iopromide. There was no significant difference in the incidence of CIN (summary odds ratio [OR] 0.50, 95% confidence interval [CI] 0.19-1.35, P = .17) and peak Scr increase (mean difference -0.01 mg/dL, 95% CI -0.08 to 0.05, P = .69) when iodixanol was compared with iopromide. But iodixanol was associated with a statistically significant reduction in cardiovascular adverse events when compared with iopromide (OR 0.47, 95% CI 0.30-0.73, P = .0009).

CONCLUSIONS

Analysis of pooled data from 8 randomized controlled trials of iodixanol against iopromide in patients with renal insufficiency undergoing coronary angiography with or without PCI showed that iodixanol nonsignificantly reduced the incidence of CIN, but was associated with a significantly reduced risk of cardiovascular adverse events when compared with iopromide.

Contrast-induced nephropathy in patients with diabetes mellitus between iso- and low-osmolar contrast media: A meta-analysis of full-text prospective, randomized controlled trials

Purpose

This study was conducted to compare iso-osmolar contrast medium, iodixanol, with low-osmolar contrast media (LOCM) for assessing contrast-induced nephropathy (CIN) incidence, exclusively in the diabetic population.

Method

A systematic search was conducted for full-text, prospective, randomized controlled trials (RCTs). The primary outcome was incidence of CIN. Medline, Cochrane Central Register of Controlled Trials, and other sources were searched until May 31, 2017.

Results

Twelve RCTs finally met the search criteria. Iodixanol did not significantly reduce the risk of CIN (risk ratio [RR]: 0.72, 95% confidence interval (CI): [0.49, 1.04], p = 0.08). However, there was significantly reduced risk of CIN when iodixanol was compared to a LOCM agent iohexol (RR: 0.32, 95% CI [0.12, 0.89]). There were no differences between iodixanol and the other non-iohexol LOCM (RR: 0.92, 95% CI [0.68, 1.25]).

Conclusion

In diabetic populations, iodixanol is not associated with a significant reduction of CIN risk. Iodixanol is associated with a reduced risk of CIN compared with iohexol, whereas no significant difference between iodixanol and other LOCM could be found.

The feasibility of low-concentration contrast and low tube voltage in computed tomography perfusion imaging: an animal study

Aim: To investigate the feasibility of low-concentration contrast (270 mg/ml) together with low tube voltage (80 kV) and adaptive iterative dose reduction (AIDR)-3D reconstruction in liver computed tomography (CT) perfusion imaging.

Method: A total of 15 healthy New Zealand rabbits received two CT scans each. The first scan (control) was acquired at 100 kV and 100 mA with iopromide (370 mg/ml), while the second scan (experimental) was acquired at 80 kV and 100 mA with iodixanol (270 mg/ml) 24 h after the first scan. The obtained images were reconstructed with filtered back projection (FBP) and AIDR-3D in the control and experimental groups respectively. The perfusion parameters (hepatic artery perfusion [HAP], portal vein perfusion [PVP], hepatic perfusion index [HPI], and total liver perfusion [TLP]) and image quality (image quality score, average CT value of abdomen aorta, signal-to-noise ratio [SNR], contrast-to-noise ratio [CNR], and figure of merit [FOM]) were compared using a paired t-test or Mann–Whitney U test between the two groups, when appropriate. The effective radiation dose and iodine intake were also recorded and compared.

Results: With the exception of the FOM criteria, the image quality and perfusion parameters were not significantly different between the two groups. The effective radiation dose and iodine intake were 38.79% and 27.03% lower respectively, in the experimental group.

Conclusion: Low-concentration contrast (iodixanol, 270 mg/ml) together with low tube voltage (80 kV) and AIDR-3D reconstruction help to reduce radiation dose and iodine intake without compromising perfusion parameters and image quality in liver CT perfusion imaging.

Post-contrast acute kidney injury - Part 1: Definition, clinical features, incidence, role of contrast medium and risk factors : Recommendations for updated ESUR Contrast Medium Safety Committee guidelines

Purpose

The Contrast Media Safety Committee (CMSC) of the European Society of Urogenital Radiology (ESUR) has updated its 2011 guidelines on the prevention of post-contrast acute kidney injury (PC-AKI). The results of the literature review and the recommendations based on it, which were used to prepare the new guidelines, are presented in two papers.

Areas covered in part 1

Topics reviewed include the terminology used, the best way to measure eGFR, the definition of PC-AKI, and the risk factors for PC-AKI, including whether the risk with intravenous and intra-arterial contrast medium differs.

Key Points

• PC-AKI is the preferred term for renal function deterioration after contrast medium.

• PC-AKI has many possible causes.

• The risk of AKI caused by intravascular contrast medium has been overstated.

• Important patient risk factors for PC-AKI are CKD and dehydration.

Is Intravenous Administration of Iodixanol Associated with Increased Risk of Acute Kidney Injury, Dialysis, or Mortality? A Propensity Score-adjusted Study

Purpose To compare the rates of acute kidney injury (AKI), emergent dialysis, and short-term mortality between patients who underwent intravenous administration of the iso-osmolar contrast material (IOCM) iodixanol 320 and patients who underwent a noncontrast computed tomography (CT) examination. Materials and Methods Study design and implementation were overseen by an institutional review board and conformed to HIPAA guidelines on patient data integrity. All patients who underwent an iodixanol-enhanced (IOCM group) or a noncontrast (noncontrast group) CT examination from January 2003 to December 2014 were identified. Patients were subdivided into subgroups of those with stage 1-2 chronic kidney disease (CKD) (estimated glomerular filtration rate [eGFR], ≥ 60 mL/min/1.73 m²), those with stage 3 CKD (eGFR, 30-59 mL/min/1.73 m²), and those with stage 4-5 CKD (eGFR < 30 mL/min/1.73 m²) and separately underwent propensity score stratification and matching. Rates of AKI, emergent dialysis, and mortality were compared between IOCM and noncontrast groups. Additional analyses incorporating intravenous fluid administration, including additional CT studies at other sites within a single institution, and a paired analysis of patients who underwent both IOCM and noncontrast CT studies during the study time frame, were also performed. Results A total of 5758 patients (1538 with stage 1-2 CKD, 2899 with stage 3 CKD, and 1321 with stage 4-5 CKD) were included in the study. After propensity score adjustment, rates of AKI, dialysis, and mortality were not significantly higher in the IOCM group compared with the noncontrast group for all CKD subgroups (AKI odds ratios [ORs], 0.74-0.91, P = .16-0.69; dialysis ORs, 0.74-2.00, P = .42-.76; mortality ORs, 0.98-1.24, P = .39-.88). Sensitivity analyses yielded similar results. Conclusion Among patients at the highest perceived risk of postcontrast AKI, intravenous administration of iodixanol for contrast material enhanced CT was not an independent risk factor for AKI, dialysis, or mortality. ^© RSNA, 2017 Online supplemental material is available for this article.

Contrast-induced acute kidney injury: A review of practical points

Contrast-induced acute kidney injury (CI-AKI) is one of the most common causes of AKI in clinical practice. CI-AKI has been found to be strongly associated with morbidity and mortality of the patients. Furthermore, CI-AKI may not be always reversible and it may be associated with the development of chronic kidney disease. Pathophysiology of CI-AKI is not exactly understood and there is no consensus on the preventive strategies. CI-AKI is an active research area thus clinicians should be updated periodically about this topic. In this review, we aimed to discuss the indications of contrast-enhanced imaging, types of contrast media and their impact on nephrotoxicity, major pathophysiological mechanisms, risk factors and preventive strategies of CI-AKI and alternative non-contrast-enhanced imaging methods.

The effect of aspirated barium sulfate, iodixanol, and diatrizoic acid on survival and lung injury in a lagomorph model

OBJECTIVES/HYPOTHESIS

Contrast agents are an integral component of the video fluoroscopic swallow study. Agents commonly used include barium sulfate (E-Z Paque), iodixanol (Visipaque), and diatrizoic acid (Gastrografin). Barium is water insoluble, whereas iodixanol and diatrizoic acid are water-soluble iodine-based agents. The detrimental effect of these agents on the lungs has not been systematically evaluated. Our aim was to evaluate and compare the effects of aspirated barium, iodixanol, and diatrizoic acid on pulmonary injury in a lagomorph model.

STUDY DESIGN

Animal model.

METHODS

Twenty adult male New Zealand White rabbits were divided into four groups (n = 5). Group 1 received 3 mL of barium sulfate injected into the trachea for 3 consecutive days. Group 2 received 3 mL of iodixanol injected into the trachea for 3 consecutive days. Group 3 received 3 mL of diatrizoic acid injected into the trachea for 3 consecutive days. A control group received 3 mL of air injected into the trachea under an identical protocol. All animals were euthanized on day 4, and the lung and trachea were harvested for blinded histopathologic analysis. The primary outcome measure was survival. The secondary endpoint was a blinded, histologic grading system of lung injury.

RESULTS

Two animals in the barium group, one in the diatrizoic acid group, and 0 animals in the iodixanol and control groups died. The overall lung injury score for the barium (60.60 ± 6.34) and iodixanol groups (52.30 ± 3.11) were significantly higher (worse) than the diatrizoic acid (49.60 ± 7.64) and control groups (37.80 ± 3.56) (P < .05). Diatrizoic acid produced the least amount of lung injury.

CONCLUSIONS

The data suggest that 3 mL of aspirated barium sulfate (E-Z Paque) over 3 consecutive days causes more severe lung injury in a lagomorph model than 3 mL of aspirated iodixanol (Visipaque) and diatrizoic acid (Gastrografin). Diatrizoic acid caused the least histologic evidence of lung injury.

LEVEL OF EVIDENCE

NA Laryngoscope, 127:E148-E152, 2017.

3-Hydroxy-3-methylglutaryl-CoA reductase enzyme inhibitors for prevention of contrast-induced nephropathy: a meta-analysis of prospective randomized controlled studies

Contrast-induced nephropathy (CIN) is a possible complication of interventional procedures that require administration of an iodinated contrast. Previous observational and small prospective randomized trials suggested that 3-hydroxy-3-methylglutaryl-CoA reductase enzyme inhibitors may reduce the incidence of CIN. We performed a meta-analysis of the effect of statins on CIN including prospective randomized, controlled trials of statin therapy. We conducted an EMBASE and MEDLINE search for studies in which patients were randomized to treatment with a statin plus standard treatment (or placebo) versus standard treatment (or placebo). We included studies that provided data on creatinine clearance, and incidence of CIN before the initiation of the treatment and at the end of the follow-up period. We identified 9 prospective randomized studies of high-dose statin treatment compared with placebo treatment for CIN prevention with 2504 controls and 2480 patients that received statins. A significant reduction in CIN was observed when pharmacologic intervention with statins was used (odds ratio, 0.45; 95% confidence interval, 0.34-0.58; P < 0.0001). In this meta-analysis of prospective controlled studies, we found a statistically significant reduction of CIN incidence in patients pretreated with high-dose statins before the procedure.

Effect of Angiotensin-Converting Enzyme Inhibitors in Contrast-Induced Nephropathy: A Meta-Analysis

AIMS

The purpose of this study was to evaluate the effect of angiotensin-converting enzyme inhibitors (ACEIs) on contrast-induced nephropathy (CIN) in patients undergoing coronary angiography or percutaneous coronary intervention (PCI).

METHODS

We searched the Medline, Embase, Cochrane Library, China National Knowledge Infrastructure, Chongqing VIP database and Wanfang database up to December 2014. Pooled risk ratios (RRs) or weighted mean difference (WMD) with their 95% CIs for the CIN incidence, serum creatinine (SCr), estimated glomerular filtration rate (eGFR) and blood urea nitrogen (BUN) of the patients were collected and calculated using the software Review Manager 5.2.

RESULTS

A total of 12 separate studies including 1,868 patients (1,011 ACEI cases and 857 controls) were considered in the meta-analysis. The overall RR of the incident CIN in the ACEI group vs. the control group was 0.95 (95% CI 0.57-1.58), and the total WMDs of the x0394;SCr, x0394;eGFR and x0394;BUN were -0.01 (95% CI -0.04 to 0.02), 5.71 (95% CI -0.66 to 12.09) and 0.78 (95% CI -0.16 to 1.73), respectively. Besides, the RR of CIN incidence in the captopril group vs. the control group was 0.72 (95% CI 0.25-2.05, p = 0.54), and the pooled WMD of the x0394;SCr was -0.13 (95% CI -0.21 to -0.06, p < 0.01).

CONCLUSION

This meta-analysis suggests that ACEIs administration has no significant influence in the CIN of patients undergoing coronary angiography or PCI; however, captopril might have the potential to prevent CIN.

Renal Safety of Iodinated Contrast Media Depending on Their Osmolarity - Current Outlooks

Iodinated contrast media (ICM) are commonly administered pharmaceutical agents. Most often they are used intravenously and intraarterially. Although iodinated contrast agents are relatively safe and widely used, adverse events occur and questions remain about their use, safety, and interactions. The most important adverse effects of contrast media include hypersensitivity reactions, thyroid dysfunction, and contrast-induced nephropathy. Radiologists must be aware of the risk factors for reactions to contrast media. Nonionic iodinated contrast agents can be divided into monomeric, low-osmolar, and dimeric, iso-osmolar classes. The osmotic characteristics of contrast media have been a significant focus in many investigations of contrast-induced nephropathy.

Coronary Computed Tomographic Angiography at Low Concentration of Contrast Agent and Low Tube Voltage in Patients with Obesity:: A Feasibility Study

RATIONALE AND OBJECTIVES

Using lower tube voltage can reduce the exposure to radiation and the dose of contrast agent. However, lower tube voltage is often linked to more noise and poor image quality, which create a need for more effective technology to resolve this problem. To explore the feasibility of coronary computed tomographic angiography (CCTA) in patients with obesity at low tube voltage (100 kV) and low contrast agent concentration (270 mg/mL) using iterative reconstruction.

MATERIALS AND METHODS

A total of 48 patients with body mass index greater than 30 kg/m(2) were included and randomly divided into two groups. Group A received a traditional protocol (iopromide 370 mg/mL + 120 kV); group B received a protocol with low tube voltage (100 kV), low contrast agent concentration (270 mg/mL), and iterative reconstruction. The effective dose (ED), average attenuation values, signal-to-noise ratio (SNR), contrast-to-noise ratio (CNR), the figure of merit (FOM), image quality scores, and the total iodine intake were compared.

RESULTS

No significant differences in average CT attenuations, SNR, CNR, and subjective scores were noticed between the two groups (P > 0.05), whereas the FOM of group B was significantly higher than that of group A. Effective radiation dose, total iodine, and iodine injection rate in group B were lower than those of group A (P <0.01).

CONCLUSIONS

In patients with obesity, isotonic contrast agent with low iodine concentration and low-dose CCTA were feasible. Substantial reduction in radiation dose and the iodine intake could be achieved without compromising the image quality.

[Contrast-induced nephropathy: An update]

Contrast-induced nephropathy (CIN) is common in hospitalized patients. Its occurrence is associated with an increased hospitalization stay and cost, morbidity and mortality. Thus, preventives strategies remain a major issue. Patients that are referred for cardiac catheterization are among the most vulnerable to develop CIN due to their comorbidities. Moreover, in some cases, such preventives measures cannot be introduced due to emergent clinical settings. After a summary regarding the properties of iodinated contrast medium, the aim of this work was to review the definition, pathophysiology, diagnosis and preventive strategies related to CIN.

Preventing Contrast-induced Renal Failure: A Guide

Contrast-induced acute kidney injury (CI-AKI) is characterised by a rapid deterioration of renal function within a few days of parenteral administration of contrast media (CM) in the absence of alternative causes. CI-AKI is the most common form of iatrogenic kidney dysfunction with an estimated prevalence of 12 % in patients undergoing percutaneous coronary intervention. Although usually self-resolving, in patients with pre-existing chronic kidney disease (CKD) or concomitant risk factors for renal damage, CI-AKI is associated with increased short-and long-term morbidity and mortality. Therefore, risk stratification based on clinical and peri-procedural characteristics is crucial in selecting patients at risk of CI-AKI who would benefit the most from implementation of preventive measures.

A Comparison of Nephrotoxicity of Contrast Medium in Elderly Patients who Underwent Renal or Peripheral Arterial Vascular Intervention

OBJECTIVE

To compare the nephrotoxicity of iodixanol in elderly patients who underwent a renal artery intervention (RAI) with those who underwent an other peripheral vascular intervention (OPI).

METHODS

Three hundred fifty-four consecutive patients (>60 years old) received iodixanol during RAI (n=150) or OPI (n=204). The level of serum creatinine (SCr) was measured at the baseline, 24 hours, 48 hours, 72 hours and 1 month after intervention.

RESULTS

Within 72 hours after the intervention, the adjusted mean of the peak SCr increase was 11.22 umol/L 〔95% confidence interval (CI): 9.21-13.24〕 in the RAI group and 12.40 umol/L (95%CI: 10.7-14.09) in the OPI group. The difference in the peak SCr increase was -1.17 umol/L (95%CI: -3.94-1.60; p=0.406). Contrast-induced nephropathy occurred in 26 patients (17.3%) of the RAI group and in 27 patients (13.2%) of the OPI group (p=0.286). Patients who underwent an RAI showed no increased risk for contrast-induced nephropathy in comparison with patients who underwent an OPI 〔adjusted odds ratio (OR)=1.108; 95%CI: 0.540-2.273; p=0.780〕.

CONCLUSION

The nephrotoxic effect of iodixanol in elderly patients who underwent RAI or OPI was comparable.

Contrast Media Injector Technology - Renal Safety During Coronarography

Aim:

This study sought to assess whether the volume and osmolarity of contrast media (CM) influences the occurrence of contrast induced nephropathy (CIN) following coronarography procedure. CIN can be defined as an increase in the serum concentration of creatinine greater than a 25% from baseline during the period of 12 to 48 hours after the administration of radiocontrast media.

Material and methods:

We examined 100 patients without diabetes with serum creatinine concentration from 45 mmol/l to 141 mmol/l and 100 patients with diabetes with serum creatinine concentration from 46 mmol/l to 161 mmol/l who underwent coronary angiography. During procedure they received iso-osmolar contrast medium, Visipaque 320 (iodixanol-320), for group without diabetes from 40 to 340 ml and for group with diabetes from 49 to 310 ml.

Results:

CIN occurred in 27 (13,5%) of the 200 study patients. There was a trend toward higher prevalence of CIN (16% vs.11%, p = 0.086) in the diabetic group compared with the non-diabetic group. Patient with diabetes received less contrast media, they are younger but number patients with CIN are higher.

Conclusion:

Increasing contrast media dose is associated with the occurrence of CIN following coronarography. But, another risk factors like diabetes mellitus, old age, male sex and preexisting kidney disease have influence of developing CIN after coronarography.

Renal-related adverse effects of intravenous contrast media in computed tomography

Renal-related adverse effects of intravascular contrast media (CM) include contrast-induced nephropathy in computed tomography and angiography. While large retrospective studies have been published, the exact pathogenesis of this condition is still unknown. We review the main international guidelines, including the American College of Radiology white paper and the guidelines of European Society of Urogenital Radiology, Royal College of Radiologists and Canadian Association of Radiologists, as well as their references, regarding this subject. We present a simplified, concise approach to renal-related adverse effects of CM, taking into consideration the basis for each recommendation in these published guidelines. This will allow the reader to better understand the rationale behind appropriate patient preparation for cross-sectional imaging.

Contrast-associated AKI in the critically ill: relevant or irrelevant?

PURPOSE OF REVIEW

Iodinated contrast media are frequently administered in ICU patients. Recent studies challenge the relevance of contrast media toxicity in ICU patients and relate occurrence of acute kidney injury to baseline characteristics and severity of illness.

RECENT FINDINGS

Various findings in studies with kidney biomarkers indicate the causal relationship between contrast media exposure and kidney damage. Contrast media exposure not only causes direct tubular damage and renal hypoperfusion but also initiates the formation of reactive oxygen species in its turn causing tissue damage. The route of administration determines the incidence of contrast-induced acute kidney injury with a higher incidence when contrast media are administered by intra-arterial route versus intravenous route. The impact of contrast-associated acute kidney injury on hospital length of stay, the need for renal replacement therapy and survival remains a matter of debate because of discrepancies between observational versus case-matched studies and limitations of the individual studies.

SUMMARY

There are diverse pathophysiologic mechanisms explaining the causal relationship between the administration of contrast media and the development of acute kidney injury. Some studies challenge the relevance of contrast media toxicity in ICU patients. However, limitations of the available studies in ICU patients preclude firm conclusions. A precautionary approach in the administration of contrast media is justified.

Contrast media controversies in 2015: imaging patients with renal impairment or risk of contrast reaction

OBJECTIVE

The incidence and significance of complications related to intravascular contrast material administration have become increasingly controversial. This review will highlight current thinking regarding the imaging of patients with renal impairment and those at risk for an allergiclike contrast reaction.

CONCLUSION

The risk of contrast-induced acute kidney injury remains uncertain for patients with an estimated glomerular filtration rate (GFR) less than 45 mL/min/1.73 m(2), but if there is a risk, it is greatest in those with estimated GFR less than 30 mL/min/1.73 m(2). In this population, low-risk gadolinium-based contrast agents appear to have a large safety margin. Corticosteroid prophylaxis remains the standard of care in the United States for patients identified to be at high risk of a contrast reaction, but it has an incomplete mitigating effect on contrast reaction rates and the number needed to treat is large.

American Thyroid Association statement on preoperative imaging for thyroid cancer surgery

BACKGROUND

The success of surgery for thyroid cancer hinges on thorough and accurate preoperative imaging, which enables complete clearance of the primary tumor and affected lymph node compartments. This working group was charged by the Surgical Affairs Committee of the American Thyroid Association to examine the available literature and to review the most appropriate imaging studies for the planning of initial and revision surgery for thyroid cancer.

SUMMARY

Ultrasound remains the most important imaging modality in the evaluation of thyroid cancer, and should be used routinely to assess both the primary tumor and all associated cervical lymph node basins preoperatively. Positive lymph nodes may be distinguished from normal nodes based upon size, shape, echogenicity, hypervascularity, loss of hilar architecture, and the presence of calcifications. Ultrasound-guided fine-needle aspiration of suspicious lymph nodes may be useful in guiding the extent of surgery. Cross-sectional imaging (computed tomography with contrast or magnetic resonance imaging) may be considered in select circumstances to better characterize tumor invasion and bulky, inferiorly located, or posteriorly located lymph nodes, or when ultrasound expertise is not available. The above recommendations are applicable to both initial and revision surgery. Functional imaging with positron emission tomography (PET) or PET-CT may be helpful in cases of recurrent cancer with positive tumor markers and negative anatomic imaging.