Prevention of Contrast Media–induced Nephrotoxicity after Angiographic Procedures

Investigations of injection strategies to use heparinized normal saline instead of contrast media for intracoronary optical coherence tomography imaging

BACKGROUND

The benefits of intravascular imaging-guided percutaneous coronary interventions (PCI) are well established. Intravascular imaging guidance improves short- and long-term outcomes, especially in complex PCI. Optical coherence tomography (OCT) has a higher resolution than intravascular ultrasound. However, the usage of OCT is mainly limited by the need to use contrast for flushing injections, which increases the risk of contrast-induced acute kidney injury, especially in patients with underlying chronic kidney disease. The aim of this study was to prove that flushing techniques with normal saline instead of contrast can be used in OCT imaging and can generate high-quality images.

METHODS

This prospective single-center observational study included patients with indications for OCT-guided PCI. For OCT pullbacks, heparinized saline was injected by an automatic pump injector at different rates, and additional extension catheters for selective coronary artery engagement were used at the operator's discretion. Recordings were made using the Ilumien Optis OCT system (Abbott) and the Dragonfly (Abbott) catheter and were analyzed at 1-mm intervals by two operators. Pullbacks were categorized as having optimal, acceptable, or unacceptable imaging quality. A clinically usable run was determined if >75% of the region of interest length was described as having optimal or acceptable imaging quality.

RESULTS

A total of 32 patients were enrolled in the study; 47 different lesions were assessed before and after PCI. In total, 91.5% of runs were described as clinically suitable for use.

CONCLUSION

Heparinized saline injections for OCT imaging are effective in generating good-quality OCT images suitable for clinical use.

Contrast Media Volume to Creatinine Clearance Ratio in Predicting Nephropathy in Patients Undergoing Percutaneous Coronary Intervention: A Systematic Review and Meta-Analysis

The studies investigated the predictive value of the contrast media volume to creatinine clearance ratio (V/CrCl) for contrast-induced nephropathy (CIN) after a percutaneous coronary intervention (PCI) showed conflicting results and different cut-off values. The objective is to evaluate V/CrCl in the prediction of CIN after PCI. PubMed, Embase, and the Cochrane library were searched for eligible studies published from inception to November 2020. The optimal cut-off points of V/CrCl for predicting CIN were examined using odds ratios (ORs) and 95% confidence intervals (CIs). The random-effect model was used for analyses. Six studies (8 datasets, 16 899 patients) were included. V/CrCl was associated with CIN (OR = 2.67, 95% CI: 1.88-3.78, P < .001; I² = 79.3%, P_{heterogeneity} < .001). V/CrCl was associated with CIN in Asians (OR = 2.13, 95% CI: 1.52-2.98, P = .022; I² = 68.8%, P_{heterogeneity} < .001) and Europeans (OR = 3.87, 95% CI: 1.77-8.45, P < .001; I² = 85.1%, P_{heterogeneity} = .001). The association between V/CrCl and CIN was observed in the prospective cohort studies (OR = 2.16, 95% CI: 1.42-3.29, P = .009; I² = 78.9%, P_{heterogeneity} < .001) and retrospective cohort studies (OR = 3.31, 95% CI: 1.82-6.02, P < .001; I² = 80.6%, P_{heterogeneity} < .001). The sensitivity analysis showed the results were robust. V/CrCl is independently associated with an increased risk of CIN. V/CrCl could be considered a reliable predictor for the development of CIN in patients undergoing PCI.

Saline as an alternative to radio-contrast for optical coherence tomography guided percutaneous coronary intervention: A prospective comparison

OBJECTIVES

To do a quantitative comparison of saline and contrast Frequency domain optical coherence tomography (FD-OCT) during percutaneous coronary intervention (PCI) optimisation.

METHODS

13 pairs of OCT runs were analysed, wherein each pair consisted of a contrast run and a heparinized saline run taken in the same coronary artery at the same position. Quantitative analysis was done comparing minimal lumen area (MLA), proximal reference diameter (PRD), distal reference diameter (DRD) and percentage area stenosis (AS) at the same anatomical location. Lesion morphologies, rendered stent view and 3D reconstruction were compared for image clarity.

RESULT

The saline OCT runs resulted in comparable MLA (3.88 ± 2.59 mm² with saline run vs 3.88 ± 2.71 mm² with contrast run; p = 0.650), PRD (3.66 ± 0.52 mm with saline vs 3.65 ± 0.52 mm with contrast; p = 0.463), DRD (2.97 ± 0.22 mm with saline vs 2.99 ± 0.88 mm with contrast; p = 0.433), and AS (59.60 ± 18.62% with saline vs 59.18 ± 19.11% with contrast; p = 0.753) with respect to the contrast runs. The Bland Altman plots of the measured parameters indicate good agreement between saline and contrast OCT. Linear regression analysis indicated the absence of proportional bias All lesion morphologies (calcified, fibrotic, thin cap fibroatheroma, macrophages, cholesterol crystals and edge dissection), 3D reconstruction and rendered stent view were clearly demonstrable in the saline OCT runs.

CONCLUSIONS

Using heparinized saline as flushing media in coronary FD-OCT may result in vessel dimensions that are comparable with contrast. Heparinized saline may be used as a contrast saving alternative for FD-OCT during PCI optimization.

Study of saline optical coherence tomography-guided percutaneous coronary intervention (SOCT-PCI Study)

AIM

The aim of this study was to evaluate the feasibility of heparinised saline as flushing media for frequency-domain optical coherence tomography (FD-OCT) image acquisition during percutaneous coronary intervention (PCI) optimisation.

METHODS AND RESULTS

Twenty-seven patients undergoing FD-OCT-guided PCI were enrolled. Heparinised saline was injected into the coronary during FD-OCT image acquisition. A total of 118 runs were analysed for image quality and diagnostic value. FD-OCT runs were categorised as follows: good runs (GRs), clinically usable runs (CURs) and clinically not usable runs (NURs); GRs and CURs were combined as clinically effective runs (ERs). Saline FD-OCT enabled visualisation of all possible coronary lesions. Of the 118 runs analysed, 61%, 27.1%, 11.9% and 88.1% were GRs, CURs, NURs and ERs, respectively. Sixty-one percent of total runs were left coronary system (LCS) and 39% were right coronary system (RCS) runs. Among LCS runs, 55.6%, 30.6%, 13.8% and 86.2% were GRs, CURs, NURs and ERs, respectively. Among RCS runs, 69.6%, 21.7%, 8.7% and 91.3% were GRs, CURs, NURs and ERs, respectively.

CONCLUSION

This is the first study to demonstrate the technical feasibility of isolated saline FD-OCT for PCI optimisation.

A novel simple experimental model for low-osmolar contrast-induced acute kidney injury using different definitions based on the levels of serum creatinine and cystatin C

Background

It remained lack of a kind of contrast-induced acute kidney injury (CI-AKI) model which was widely used in clinical practice and comparable to CI-AKI in humans.

Methods

Fifty Sprague-Dawley rats were divided into five groups of 10 rats each: (1) sham group (normal saline [NS] + NS); (2) NS plus low osmolality contrast medium (CM15) (NS + CM15); (3) furosemide (FM) plus NS (FM + NS); (4) FM + CM10; and (5) FM + CM15.We measured the levels of serum creatinine (SCr), cystatin C (cys-C) and histopathological scores of kidney tissues.

Results

SCr level in the FM + CM15 group were significantly increased after CM exposure compared with baseline levels (32.9 ± 4.57 vs. 158.7 ± 14.48 μmol/L, p < 0.001). Minor changes were found about the SCr levels between the pre- and post-exposure CM or NS treatment in the other groups. Additionally, the cys-C levels after CM exposure were increased compared with pretreatment levels in the FM + CM15 group (0.08 ± 0.03 vs. 0.18 ± 0.05 mg/L, p < 0.001). Minor changes were noted in the FM + NS group before and after NS administration. Only rats in the FM + CM15 group developed CI-AKI with the definitions of SCr or cys-C. Comparing to the FM + NS group, the histopathological scores were significantly increased in the FM + CM15 group.

Conclusions

A simple and reliable animal model for low osmolality contrast medium-induced AKI was established, which is similar to clinical CI-AKI based on different definitions for AKI.

Contrast media use in patients with chronic kidney disease undergoing coronary angiography: A systematic review and meta-analysis of randomized trials

BACKGROUND

Patients with chronic kidney disease (CKD) undergoing coronary angiography (CA), adequate hydration and minimizing volume of contrast media (CM) are class 1b recommendations for preventing contrast induced nephropathy (CIN). Current data are insufficient to justify specific recommendations about isoosmolar vs. low-osmolar contrast media by the ACCF/AHA/SCAI guidelines.

METHODS

Randomized trials comparing IOCM to LOCM in CKD stage 3 and above patients undergoing CA, and reporting incidence of CIN (defined by a rise in creatinine of 25% from baseline) were included in the analysis. The secondary outcome of the study was the incidence of serum creatinine increase by >1mg/dl.

RESULTS

A total of 2839 patients were included in 10 trials, in which 1430 patients received IOCM and 1393 received LOCM. When compared to LOCM, IOCM was not associated with significant benefit in preventing CIN (OR=0.72, [CI: 0.50-1.04], P=0.08, I2=59%). Subgroup analysis revealed non-significant difference in incidence of CIN based on baseline use of N-acetylcystine (NAC), diabetes status, ejection fraction, and whether percutaneous coronary intervention vs coronary angiography alone was performed. The difference between IOCM and LOCM was further attenuated when restricted to studies with larger sample size (>250 patients) (OR=0.93; [CI: 0.66-1.30]) or when compared with non-ionic LOCM (OR=0.79, [CI: 0.52-1.21]).

CONCLUSION

In patients with CKD stage 3 and above undergoing coronary angiography, use of IOCM showed overall non-significant difference in incidence of CIN compared to LOCM. The difference was further attenuated when IOCM was compared with non-ionic LOCM.

Safe limits of contrast vary with hydration volume for prevention of contrast-induced nephropathy after coronary angiography among patients with a relatively low risk of contrast-induced nephropathy

BACKGROUND

Few studies have investigated the safe limits of contrast to prevent contrast-induced nephropathy (CIN) based on hydration data. We aimed to investigate the relative safe maximum contrast volume adjusted for hydration volume in a population with a relatively low risk of CIN.

METHODS AND RESULTS

The ratios of contrast volume-to-creatinine clearance (V/CrCl) and hydration volume to body weight (HV/W) were determined in patients undergoing cardiac catheterization. Receiver-operator characteristic curve analysis based on the maximum Youden index was used to identify the optimal cutoff for V/CrCl in all patients and in HV/W subgroups. Eighty-six of 3273 (2.6%) patients with mean CrCl 71.89±27.02 mL/min developed CIN. Receiver-operator characteristic curve analysis indicated that a V/CrCl ratio of 2.44 was a fair discriminator for CIN in all patients (sensitivity, 73.3%; specificity, 70.4%). After adjustment for other confounders, V/CrCl >2.44 continued to be significantly associated with CIN (adjusted odds ratio, 4.12; P<0.001) and the risk of death (adjusted hazard ratio, 2.62; P<0.001). The mean HV/W was 12.18±7.40. We divided the patients into 2 groups (HV/W ≤12 and >12 mL/kg). The best cutoff value for V/CrCl was 1.87 (sensitivity, 67.9%; specificity, 64.4%; adjusted odds ratio, 3.24; P=0.011) in the insufficient hydration subgroup (HV/W, ≤12 mL/kg; CIN, 1.32%) and 2.93 (sensitivity, 69.0%; specificity, 65.0%; adjusted odds ratio, 3.04; P=0.004) in the sufficient hydration subgroup (HV/W, >12 mL/kg; CIN, 5.00%).

CONCLUSIONS

The V/CrCl ratio adjusted for HV/W may be a more reliable predictor of CIN and even long-term outcomes after cardiac catheterization. We also found a higher best cutoff value for V/CrCl to predict CIN in patients with a relatively sufficient hydration status, which may be beneficial during decision-making about contrast dose limits in relatively low-risk patients with different hydration statuses.

Lowering iodinated contrast concentration in infrainguinal endovascular interventions: a three-armed randomized controlled non-inferiority trial

Objectives

To determine the influence of lowering iodinated contrast concentration on confidence of interventional radiologists in diagnosing and treating lesions during endovascular interventions in patients with symptomatic peripheral arterial disease (PAD).

Methods

A randomized controlled non-inferiority trial was performed in 60 patients. Intervention was performed with contrast concentrations (in mg of iodine per mL, mgI/mL) of 300 (standard), 240, or 140 mgI/mL. Primary outcome was confidence (score 0-100 %) of radiologists in diagnosing and treating arterial lesions. Secondary outcomes were procedural iodine load and image quality (i.e. non-diagnostic, limited, diagnostic, exemplary).

Results

Median confidence scores in diagnosing lesions were 100 % (range 81-100 %) for the 300 group (n = 21), 100 % (range 82-100 %) for the 240 group (n = 19), and 100 % (range 91-100 %) for the 140 group (n = 20) (both p = 1.00 compared to the 300 group). Median scores for treating lesions in the 240 and 140 groups, 100 % (range 79-100 %, p = 0.40), and 100 % (range 63-100 %, p = 0.25), respectively, were not lower compared to the 300 group (median 100 %, range 78-100 %). Procedural iodine load was lower in the 240 (24.3 ± 7.6 g, p = 0.022) and 140 groups (17.8 ± 5.6 g, p < 0.001) compared to the 300 group (29.7 ± 6.3 g). Image quality was diagnostic for all groups.

Conclusion

Using iodine contrast of 140 mgI/mL for diagnosis and interventions in PAD patients significantly reduces administered iodine load without compromising image quality. Future use of lower iodine dose is recommended.

Key Points

• Lower iodinated contrast concentration during endovascular intervention does not decrease radiologist’s confidence.

• Image quality of standardized angiographies remains diagnostic using 140 mgI/mL iodinated contrast concentration.

• Iodine load during intervention can be decreased by >40 % when using 140 mgI/mL.

• Implementing the use of a lower iodinated contrast concentration will reduce the costs of the procedure.

Benefits and problems of transarterial therapy in patients with hepatocellular carcinoma and chronic kidney disease

PURPOSE

To evaluate the feasibility of transarterial therapy (transcatheter arterial chemoembolization and transcatheter arterial infusion) for patients with hepatocellular carcinoma and chronic kidney disease (CKD).

MATERIALS AND METHODS

The study enrolled 35 patients who received transarterial therapy. The patients were classified into a CKD group (n = 10 nondialysis chronic kidney disease [NDCKD] and n = 9 end-stage renal disease [ESRD]) or a non-CKD group (n = 16). The survival rates between the two groups were compared using two different starting points: (a) from initial diagnosis of hepatocellular carcinoma and (b) from enrollment in the study. The tolerance of transarterial therapy in patients with CKD was evaluated by comparing the incidence of major adverse events.

RESULTS

The 2-year and 5-year survival rates from initial diagnosis were 83.9% and 53.8% in the CKD group and 70.1% and 40.4% in the non-CKD group (P = .478). The corresponding 3-year survival rate from enrollment in the two groups was 25.6% and 41.2%, respectively (P = .995). The 2-year and 5-year survival rates from initial diagnosis were 70.1% and 40.4% in the non-CKD group, 90.0% and 39.4% in NDCKD patients, and 76.2% and 76.2% in ESRD patients (P = .380). The corresponding 2-year survival rates from enrollment in these groups were 54.9%, 48.0%, and 48.6% (P = .943). Severe contrast-induced nephropathy (n = 3) and late-onset death caused by cholesterol crystal embolism (n = 1) were observed in the NDCKD group.

CONCLUSIONS

Transcatheter arterial chemoembolization is feasible in patients with CKD by instituting periprocedural hemodialysis with similar 2-year and 5-year survival compared with patients without CKD.

Can selective inhibitors of cyclic guanosine monophosphate (cGMP)-specific phosphadiesterase type 5 (PDE 5) offer protection against contrast induced nephropathy?

Parenchymal hypoxia within the renal outer medulla plays an important role in the pathogenesis of contrast induced nephropathy (CIN). Nitric oxide (NO) is crucial for medullary oxygenation by enhancing regional blood flow. Augmenting the effect of NO in the renal medulla by the use of selective inhibitors of cyclic guanosine monophosphate (cGMP)-specific phosphadiesterase type 5 (PDE 5) such as sildenafil (Viagra™), vardenafil (Levitra™) or tadalafil (Cialis™) could reduce the severity of the hypoxic insult induced by the contrast medium and reduce the risk of CIN. Prophylactic administration of one of these drugs particularly the long acting one tadalafil before and after the administration of CM could offer a simple and rational approach to reduce the risk of this complication. This hypothesis deserves serious investigation to determine its clinical efficacy.

The relationship between hyperuricemia and the risk of contrast-induced acute kidney injury after percutaneous coronary intervention in patients with relatively normal serum creatinine

OBJECTIVES

Hyperuricemia is a risk factor for contrast-induced acute kidney injury in patients with chronic kidney disease. This study evaluated the value of hyperuricemia for predicting the risk of contrast-induced acute kidney injury in patients with relatively normal serum creatinine who were undergoing percutaneous coronary interventions.

METHODS AND RESULTS

A total of 788 patients with relatively normal baseline serum creatinine (<1.5 mg/dL) undergoing percutaneous coronary intervention were prospectively enrolled and divided into a hyperuricemic group (n = 211) and a normouricemic group (n = 577). Hyperuricemia is defined as a serum uric acid level>7 mg/ dL in males and >6 mg/dL in females. The incidence of contrast-induced acute kidney injury was significantly higher in the hyperuricemic group than in the normouricemic group (8.1% vs. 1.4%, p<0.001). In-hospital mortality and the need for renal replacement therapy were significantly higher in the hyperuricemic group. According to a multivariate analysis (adjusting for potential confounding factors) the odds ratio for contrast-induced acute kidney injury in the hyperuricemic group was 5.38 (95% confidence interval, 1.99-14.58; p = 0.001) compared with the normouricemic group. The other risk factors for contrast-induced acute kidney injury included age >75 years, emergent percutaneous coronary intervention, diuretic usage and the need for an intra-aortic balloon pump.

CONCLUSION

Hyperuricemia was significantly associated with the risk of contrast-induced acute kidney injury in patients with relatively normal serum creatinine after percutaneous coronary interventions. This observation will help to generate hypotheses for further prospective trials examining the effect of uric acid-lowering therapies for preventing contrast-induced acute kidney injury.

Radiographic assessment of splenic injury without contrast: is contrast truly needed?

INTRODUCTION

Computed tomography (CT) has become an essential tool in the assessment of the stable trauma patient. Intravenous (i.v.) contrast is commonly relied upon to provide superior image quality, particularly for solid-organ injury. However, a substantial proportion of injured patients have contraindications to i.v. contrast. Little information exists concerning the repercussions of CT imaging without i.v. contrast, specifically for splenic injury.

METHODS

We performed a retrospective analysis using data from our trauma registry and chart review as part of a quality improvement project at our institution. All patients with splenic injury, during a 3-year period (2008-2010), where a CT of the abdomen without i.v. contrast (DRY) early during their admission were selected. All splenic injuries had to have been verified with abdominal CT imaging with i.v. contrast (CONTRAST) or via intraoperative findings. DRY images were independently read by a single, blinded, radiologist and assessed for parenchymal injury or "suspicious" splenic injury findings and compared with CONTRAST imaging results or intraoperative findings.

RESULTS

During the time period of the study, 319 patients had documented splenic injury with 44 (14%) patients undergoing DRY imaging, which was also verified by CONTRAST imaging or operative findings. Splenic parenchymal injury was only visualized in 38% of patients DRY patients. "Suspicious" splenic injury radiographic findings were common. When these less-specific findings for splenic injury were incorporated in the radiographic assessment, DRY imaging had more than 93% sensitivity for detecting splenic injury.

CONCLUSION

DRY imaging is increasingly being performed after injury and has a low sensitivity in detecting splenic parenchymal injury. However, less-specific radiographic findings suspicious for splenic injury in combination provide high sensitivity for the detection of splenic injury. These results suggest CONTRAST imaging is preferred to detect splenic injury; however, in those patients who have contraindications to i.v. contrast, DRY imagining may be able to select those who require close monitoring or intervention.

Contrast medium volume to creatinine clearance ratio: a predictor of contrast-induced nephropathy in the first 72 hours following percutaneous coronary intervention

OBJECTIVES

To investigate the predictive value of the contrast media volume to creatinine clearance (V/CrCl) ratio for the risk of contrast-induced nephropathy (CIN) (i.e., within 48-72 hr) and to determine a relatively safe V/CrCl cut-off value to avoid CIN in patients following percutaneous coronary intervention (PCI).

BACKGROUND

The V/CrCl ratio is a pharmacokinetic risk factor for an early abnormal increase in serum creatinine (i.e., within 24 hr) after PCI.

METHODS

V/CrCl ratios were obtained from 1,140 consecutive consenting patients after unselective PCI. Receiver-operator characteristic (ROC) curves were used to identify the optimal sensitivity for the observed range of V/CrCl. The predictive value of V/CrCl for the risk of CIN was assessed using multivariate logistic regression.

RESULTS

Fifty-five (4.8%) patients out of 1,140 developed CIN. There was a significant association between higher V/CrCl ratio values and risk of CIN in the overall population: 1.4%, 1.4%, 5.7%, and 10.9% for quartile 1 (Q1) of the V/CrCl value (<1.56, n = 283), Q2 (1.56-2.27, n = 289), Q3 (2.28-3.42, n = 282), and Q4 (>3.42, n = 285) of contrast, respectively (P < 0.001). ROC curve analysis indicated that a V/CrCl ratio of 2.62 was a fair discriminator for CIN (C-statistic 0.73). After adjusting for other known predictors of CIN, V/CrCl ratios > 2.62 remained significantly associated with CIN (odds ratio: 2.20; 95% confidence interval: 1.00-4.81, P < 0.05).

CONCLUSION

A V/CrCl ratio > 2.62 was a significant and independent predictor of CIN after PCI in unselected patients.

Contrast induced nephropathy: updated ESUR Contrast Media Safety Committee guidelines

PURPOSE

The Contrast Media Safety Committee (CMSC) of the European Society of Urogenital Radiology (ESUR) has updated its 1999 guidelines on contrast medium-induced nephropathy (CIN).

AREAS COVERED

Topics reviewed include the definition of CIN, the choice of contrast medium, the prophylactic measures used to reduce the incidence of CIN, and the management of patients receiving metformin. Key Points • Definition, risk factors and prevention of contrast medium induced nephropathy are reviewed. • CIN risk is lower with intravenous than intra-arterial iodinated contrast medium. • eGFR of 45 ml/min/1.73 m (2) is CIN risk threshold for intravenous contrast medium. • Hydration with either saline or sodium bicarbonate reduces CIN incidence. • Patients with eGFR ≥ 60 ml/min/1.73 m (2) receiving contrast medium can continue metformin normally.

[Renal failure: diagnostic work-up]

The purpose of this article is to review the diagnostic work-up of renal failure, acute or chronic. The role of the radiologist is to exclude the presence of a curable etiology such as urinary tract obstruction or vascular thrombosis. Renal ultrasound with Doppler imaging is the imaging modality of choice for this indication, and the use of a contrast agent is useful to evaluate renal perfusion. Non-contrast CT remains valuable for the diagnosis of some urinary tract pathologies. Finally, MRI is the most comprehensive imaging modality for the evaluation of the urinary tract, but performed as a second line modality mainly for practical reasons but also due to the non-negligible risk of nephrogenic systemic fibrosis secondary to the intravenous administration of gadolinium based contrast agent.

The contrast medium volume to estimated glomerular filtration rate ratio as a predictor of contrast-induced nephropathy after primary percutaneous coronary intervention

BACKGROUND

Contrast-induced nephropathy (CIN) is a serious complication in percutaneous coronary intervention (PCI) patients, which may be related to the contrast dose used during cardiac catheterization.

METHODS

We prospectively investigated 277 consecutive consenting patients with acute ST-segment elevation myocardial infarction (STEMI) who were given primary PCI, and we calculated their ratio of volume of contrast media to estimated glomerular filtration rate (V/eGFR). Receiver-operator characteristic methods were used to identify the optimal sensitivity for the observed range of V/eGFR for CIN (i.e., within 48-72 h). The predictive value of V/eGFR for the risk of CIN was assessed using multivariable logistic regression.

RESULTS

Twenty-five (9%) patients developed CIN. The baseline mean and median V/eGFR values were significantly greater among patients with CIN (mean 3.22 ± 1.53, median 2.97, and interquartile range 1.90-4.17) than among those without CIN (mean 1.80 ± 1.00, median 1.52, and interquartile range 1.12-2.21, P < 0.001). The receiver-operator characteristic curve analysis indicated that a V/eGFR ratio of 2.39 was a fair discriminator for CIN (C statistic 0.81). After adjusting for other known predictors of CIN, a V/eGFR ratio ≥ 2.39 remained significantly associated with CIN (odds ratio 4.24, 95% confidence interval 1.23-14.66, P < 0.05).

CONCLUSION

A V/eGFR ratio ≥ 2.39 was a significant and independent predictor of CIN after primary PCI in patients with STEMI.

Electromagnetic navigation for thoracic aortic stent-graft deployment: a pilot study in swine

PURPOSE

To determine the feasibility of electromagnetic tracking as a method to augment conventional imaging guidance for the safe delivery, precise positioning, and accurate deployment of thoracic aortic endografts.

MATERIALS AND METHODS

Custom guide wires were fabricated, and the delivery catheters for thoracic aortic endoprostheses were retrofitted with integrated electromagnetic coil sensors to enable real-time endovascular tracking. Preprocedure thoracic computed tomographic (CT) angiograms were obtained after the placement of fiducial skin patches on the chest wall of three anesthetized swine, enabling automatic registration. The stent-graft deployment location target near the subclavian artery was selected on the preprocedure CT angiogram. Two steps were analyzed: advancing a tracked glidewire to the aortic arch and positioning the tracked stent-graft assembly by using electromagnetic guidance alone. Multiple CT scans were obtained to evaluate the accuracy of the electromagnetic tracking system by measuring the target registration error, which compared the actual position of the tracked devices to the displayed "virtual" electromagnetic-tracked position. Postdeployment CT angiography and necropsy helped confirm stent-graft position and subclavian artery patency.

RESULTS

A stent-graft was successfully delivered and deployed in each of the three animals by using real-time electromagnetic tracking alone. The mean fiducial registration error with autoregistration was 1.5 mm. Sixteen comparative scans were obtained to determine the target registration error, which was 4.3 mm +/- 0.97 (range, 3.0-6.0 mm) for the glidewire sensor coil. The mean target registration error for the stent-graft delivery catheter sensor coil was 2.6 mm +/- 0.7 (range, 1.9-3.8 mm). The mean deployment error for the stent-graft, defined as deployment deviation from the target, was 2.6 mm +/- 3.0.

CONCLUSIONS

Delivery and deployment of customized thoracic stent-grafts with use of electromagnetic tracking alone is feasible and accurate in swine. Combining endovascular electromagnetic tracking with conventional fluoroscopy may further improve accuracy and be a more realistic multimodality approach.

CT and radiation-related cancer risk-time for a paradigm shift?

The use of CT in the US has been increasing exponentially over the past decade. The greatest increases in CT use have been in pediatric diagnosis and adult screening. Unfortunately, there is little cognizance among health-care providers (or their patients) about the relative latent cancer risks associated with repetitive exposure to ionizing radiation. Given the exposure of a relatively high proportion of the population to these tests, it is incumbent on health-care providers to have an improved understanding of these risks and discuss them accordingly with their patients. The risks and benefits of these tests should be carefully analyzed and radiation exposure risk assessment should be conducted as part of the selection of diagnostic and screening tests. Appropriate discussion between physicians and patients of the risks associated with radiographic studies is warranted to inform patients of the longitudinal risks of subsequent testing.

Prevention of contrast-induced nephropathy: an overview

Many unknowns remain concerning how best to reduce a patient's risk of contrast-induced nephropathy (CIN). Many interventions have been proposed, but few have gone unchallenged, and new questions have arisen from analysis of serum creatinine variations in patients who have not been exposed to radiographic iodinated contrast media (RICM). Use of alternate imaging tests that do not use RICM is the most direct way to avoid CIN. Hydration remains the bulwark of intervention when RICM must be administered. The administration of N-acetylcysteine is a popular pharmacologic prophylaxis against CIN but its efficacy is unclear. Hemodialysis has not been effective, but hemofiltration has shown good results in limited series.

Sodium bicarbonate plus isotonic saline versus saline for prevention of contrast-induced nephropathy in patients undergoing coronary angiography: a randomized controlled trial

BACKGROUND

There is controversy about the prophylactic measures proposed for the prevention of contrast-induced nephropathy (CIN). We aim to compare the efficacy of the combination of sodium bicarbonate and isotonic saline and that of isotonic saline alone in preventing CIN.

STUDY DESIGN

Randomized double-blind controlled trial.

SETTING & PARTICIPANTS

265 consecutive patients 18 years or older with a serum creatinine level of 1.5 mg/dL or greater undergoing elective coronary angiography from August 2007 to June 2008 in Tehran Heart Center, Tehran, Iran.

INTERVENTION

Study participants were randomly assigned to receive either 75 mL of 8.4% sodium bicarbonate added to 1 L of isotonic saline (n = 135) or isotonic saline alone (n = 130) as a bolus of 3 mL/kg for 1 hour before contrast injection, followed by an infusion of 1 mL/kg/h for 6 hours after the procedure.

OUTCOMES & MEASUREMENTS

The primary end point was an absolute (>or=0.5 mg/dL) or relative (>or=25%) increase in serum creatinine level 48 hours after the procedure (CIN).

RESULTS

There were no significant differences between the bicarbonate and saline groups regarding baseline demographic and biochemical characteristics, including baseline serum creatinine level (1.63 +/- 0.32 [SD] versus 1.66 +/- 0.50 mg/dL), baseline glomerular filtration rate (46.4 +/- 12 versus 45.4 +/- 12 mL/min/1.73 m(2)), and baseline urine pH (5.42 +/- 0.6 versus 5.46 +/- 0.8). Nine patients (7.4%) receiving sodium bicarbonate developed CIN as opposed to 7 patients (5.9%) in the saline group, which was not statistically different (odds ratio, 1.26; 95% confidence interval, 0.45 to 3.50; P = 0.6).

LIMITATIONS

The trial did not follow up participants to assess need for dialysis and mortality rate.

CONCLUSION

The combination therapy of sodium bicarbonate plus saline does not offer additional benefits over hydration with saline alone in the prevention of CIN.

[Anesthesia in interventional neuroradiology]

Interventional neuroradiology procedures have become increasingly complex, requiring planning and coordination. Key roles are played by the anesthesiologist and the radiologist, as well as by technicians and nurses. This review aims to analyze the anesthesiologist's part in managing these procedures, from the start of the intervention through the immediate postoperative period. First concerns are to assure patient safety during transfer, maintain the airway, keep the patient immobile and hemodynamically stable, and manage anticoagulant and antiplatelet treatments. Rapid awakening must also be assured so that the patient's neurologic status can be assessed in situ. The anesthesiologist should treat any neurologic complications that develop and that might lead to emergency situations during the procedures.

Negligible effect of non-ionic radiocontrast medium exposure on microalbuminuria in patients undergoing coronary angiography

Contrast-induced nephropathy (CIN) remains one of the most common hospital-acquired acute renal deterioration in patients undergoing angiographic procedure. Transient and massive non-selective proteinuria of glomerular origin was previously reported in patients with stable renal function shortly after ionic radiocontrast medium (RCM) exposure. Since non-ionic RCM is mostly used nowadays for coronary angiographic procedures, the effects of non-ionic RCM exposure on microalbuminuria might be worthy to be clarified. By measuring urine albumin-creatinine-ratio, we found that exposure to non-ionic, low osmolar RCM has almost negligible effect on either the presence or the levels of microalbuminuria in patients who underwent coronary angiography using ordinary dose. The findings of neutral effect of non-ionic RCM on microalbuminuria in our study might offer another rationale in an effort to prevent CIN. Further large-scaled clinical trials in delineating the effects on microalbuminuria after non-ionic RCM exposure were warranted, particularly in those with pre-existing renal insufficiency, to clarify the clinical implications of our study results.

Contrast-induced nephropathy: are there differences between low osmolar and iso-osmolar iodinated contrast media?

It is acknowledged that high osmolar contrast media are more nephrotoxic than low (LOCM) or iso-osmolar contrast media (IOCM). However, it remains contentious whether the IOCM are less nephrotoxic in comparison with LOCM. This article reviews published clinical studies that investigated this issue and demonstrates there are no conclusive data to indicate that there is a definite difference in renal tolerance between LOCM and IOCM. All these agents are potentially nephrotoxic in patients with advanced renal impairment. In these patients the smallest possible dose of IOCM or LOCM should be used in addition to adequate hydration to minimize the risk of contrast nephropathy.

Evaluation of microalbuminuria after non-ionic radiocontrast medium exposure in patients undergoing coronary angiography

Transient and massive glomerular proteinuria, previously reported as one of the nephrotoxic reactions after ionic radiocontrast medium (RCM) exposure, is rarely observed in patients since the introduction of non-ionic RCM. However, whether the very low-range microalbuminuria might be encountered after non-ionic RCM exposure remains unknown. In this study we sought to investigate the effects of non-ionic RCM (Ultravist 370) exposure on the presence of microalbuminuria, defined as urine albumin-to-creatinine ratio (UACR) >30 mg/g, by a turbidmetric method in total of 64 patients (17 female, mean age 58+/-12 years) undergoing coronary angiography. The results showed that after non-ionic RCM (mean volume 103+/-57 ml) exposure, no significant differences were found in urinary albumin concentration or UACR; however, urinary creatinine was significantly reduced from 116+/-62 to 69+/-43 mg/dl (p<0.001). Changes in the presence of microalbuminuria before and after procedure were also not significant (p=0.891, McNemar test). In conclusion, non-ionic RCM exposure during CAG had negligible effect on the excretion of urinary albumin even within the detection range of microalbuminuria.

Iosimenol, a new non-ionic dimeric contrast medium, does not induce immunoreactivity in the popliteal lymph node assay

Animal studies in mice were conducted to determine the potential immunoreactivity of the new non-ionic dimeric contrast medium (CM) iosimenol using the PLNA and flow cytometric analyses. Comparative studies were performed with iodixanol. The known immune-reactive substance strepozotocin (STZ) and vehicle injections served as positive and negative controls, respectively. Our experiments did not show any immunological effect of iosimenol, concluding that the new CM iosimenol may be beneficial for use in high-risk patients.

Side-branched AAA stent graft insertion using navigation technology: a phantom study

OBJECTIVE

To evaluate the feasibility of a side-branched stent graft inserted in an artificial abdominal aortic aneurysm (AAA), using navigation technology, and to compare procedure duration and dose of radiation with control trials.

METHODS

A custom-made stent graft was inserted into an artificial AAA using navigation technology in combination with fluoroscopy. The navigation technology was based on three-dimensional visualization of computed tomography data and electromagnetic tracking of microposition sensors. The stent graft had integrated position sensors in side branch and introducer and was guided into proper position with the aid of three-dimensional images. Control trials were performed with fluoroscopy alone.

RESULTS

It was feasible to insert a side-branched stent graft using three-dimensional navigation technology. The navigation-guided trials had a significantly lower X-ray load (p < 0.001), but showed no difference in the duration of the procedures (p = 0.34) as compared with controls.

CONCLUSIONS

Inserting a side-branched stent graft in an artificial AAA using navigation technology is feasible. Side-branched stent grafts and navigation systems may become useful in the endovascular treatment of complicated aortic aneurysms.

Severe methotrexate toxicity precipitated by intravenous radiographic contrast

Methotrexate (MTX), a widely used anticancer agent, and intravenous iodinated contrast used for radiographic studies can both cause acute renal failure. Their combined exposure may place patients at higher risk for renal failure. This report describes 2 pediatric patients with MTX toxicity precipitated by the use of intravenous radiographic contrast. One patient recovered with leucovorin rescue therapy, whereas the second patient responded to carboxypeptidase-G2. Both patients suffered MTX-related toxicities including myelosuppression and mucositis, but recovered full renal function and tolerated further high-dose MTX therapy. These cases suggest that intravenous iodinated contrast should be avoided in patients receiving high-dose MTX.

Aortic root catheter-directed coronary CT angiography in swine: coronary enhancement with minimum volume of iodinated contrast material

OBJECTIVE

The purpose of this study was to evaluate the minimum amount of contrast material for coronary imaging with aortic root catheter-directed enhancement and 64-MDCT angiography (MDCTA).

MATERIALS AND METHODS

A 64-MDCT scanner was used after animal institutional review board approval to study four swine (40-60 kg). Heart rate reduction to 65 beats per minute was achieved with atenolol by mouth and i.v. Cardizem. Common femoral artery access was obtained with a 5-French micropuncture kit and sonographic guidance. A diffusiontip (640 side holes), 5-French pigtail catheter was positioned in the aortic root on the CT table with a retrofitted C-arm fluoroscopy unit and connected to an arterial power injector. Aortic root MDCTA (retrospective ECG gating; collimation, 0.6 mm; tube rotation time, 0.33 second; scanning time, 10-12 seconds; tube voltage, 120 kVp; effective mAs, 850 mAs; pitch, 0.2; field of view, 109-123 mm; slice thickness and increment, 0.6 and 0.3 mm) was begun 1 second after the injection of 100 mL of various Visipaque (iodixanol) concentrations (10%, 20%, 30%, 40%) at 10 mL/s. Coronary mean and peak densities, 3D maximum intensity projections, and 4D projections were obtained.

RESULTS

The mean pooled coronary attenuation values (H +/- SD) for the right (RCA), left anterior descending (LAD), and left circumflex (LCx) coronary arteries at various concentrations (10%, 20%, 30%, 40%) were as follows: 10% (RCA [232.6 +/- 64.0], LAD [180.4 +/- 45.1], and LCx [176.6 +/- 56.2]); 20% (RCA [383.0 +/- 98.7], LAD [324.3 +/- 60.1], and LCx [331.8 +/- 105.5]); 30% (RCA [441.8 +/- 137.6], LAD [401.3 +/- 125.8], and LCx [418.5 +/- 173.0]); and 40% (RCA [717.3 +/- 377.7], LAD [573.3 +/- 233.3], and LCx [584.8 +/- 189.0]). Coronary imaging with aortic root MDCTA was feasible at all concentrations, and the attenuation values were statistically significantly greater than 250 H at 20%, 30%, and 40% (p < 0.05). The attenuation values with aortic root MDCTA using one fifth of the volume of contrast material are comparable to those currently achieved both clinically and experimentally with peripheral i.v. MDCTA.

CONCLUSION

Aortic root MDCTA can depict the coronary arteries with as little as 20 mL of contrast material. This may provide an alternative means of coronary evaluation in patients with renal insufficiency.

Contrast Medium Administration in the Elderly Patient: Is Advancing Age an Independent Risk Factor for Contrast Nephropathy after Angiographic Procedures?

Contrast medium-induced nephropathy (CMIN) is the third leading cause of hospital-acquired acute renal dysfunction. Even if the number of patients over 75 years of age undergoing diagnostic and/or interventional procedures and requiring administration of contrast medium (CM) is growing constantly, at present there is no definitive consensus regarding the role of advancing age and related morphologic or functional renal changes as an independent risk factor for CMIN. The authors review the evidence from recent medical literature on the definition, pathophysiology, and clinical presentation of CMIN as well as therapeutic approaches to its prophylaxis. Attention is focused on advancing age as a preexisting physiologic condition that is, per se, able to predispose the patient to CM-induced renal impairment, assuming that every elderly patient is potentially at risk for CMIN.

Tratamento endovascular do aneurisma da aorta abdominal em paciente com insuficiência renal crônica

A insuficiência renal crônica não-dialítica é uma contra-indicação relativa ao tratamento endovascular dos aneurismas da aorta abdominal. O uso de contrastes alternativos, como o gadolínio, além de fornecer imagens de baixa qualidade, está relacionado à nefrotoxicidade. Relatamos um caso de tratamento endovascular de aneurisma da aorta abdominal guiado por eco-Doppler colorido. Um paciente masculino de 82 anos, com aneurisma da aorta abdominal de 55 mm de diâmetro e clearance de creatinina de 17 ml/min, recebeu implante de endoprótese aórtica modular bifurcada, utilizando este método de imagem associado à radioscopia. Não foi empregado contraste iodado. O resultado imediato e os controles de 1 e 6 meses revelam completa exclusão do aneurisma. A função renal permanece inalterada. Concluímos que o implante de endoprótese guiado por eco-Doppler colorido em pacientes com insuficiência renal crônica não terminal e com anatomia favorável é um método factível e seguro.

Adverse Events after Unenhanced and Monomeric and Dimeric Contrast-enhanced CT: A Prospective Randomized Controlled Trial

PURPOSE

To prospectively evaluate adverse events (AEs) in patients who underwent nonionic monomeric or dimeric contrast media-enhanced computed tomography (CT) and to compare these effects with AEs in patients who underwent unenhanced CT.

MATERIALS AND METHODS

Local ethics committee approval and written informed consent were obtained. Patients were randomly assigned to the dimeric group, monomeric group, or concurrent control group. Acute (occurring during or within 1 hour after contrast agent injection) and delayed (occurring between 1 hour and 7 days after contrast agent injection) AEs were evaluated and categorized (mild, not requiring treatment; moderate, self-limiting AE requiring simple treatment; severe, AE requiring extensive treatment or endangering life). The two-sided Fisher exact test and the Mann-Whitney U and Wilcoxon signed rank tests were used for statistical analysis.

RESULTS

A total of 895 patients were recruited. Acute AEs were noted significantly (P < .05) more often in the monomeric group (44.8% [133 of 297 patients]) than in the dimeric (23.7% [71 of 300 patients]) or control (9.4% [28 of 298 patients]) groups. Two moderate acute AEs were noted in one patient in each contrast agent group; all other acute AEs were mild. There was no significant difference in the overall incidence of delayed AEs between the dimeric and monomeric groups (53.1% [139 of 262 patients] vs 50.8% [131 of 258 patients]). Delayed cutaneous AEs were noted significantly (P < .05) more often in the dimeric group. A total 16 AEs (2.0%) were moderate; no AE was severe.

CONCLUSION

The dimeric contrast agent caused fewer acute AEs than the monomeric contrast agent; however, the dimeric and monomeric agents caused a similar overall number of delayed AEs. Delayed cutaneous symptoms were noted more often with the dimeric contrast agent. Both contrast agents were safe in that no severe AEs and only a few moderate AEs were observed.

Contrast-medium-induced nephropathy: is there a new consensus? A review of published guidelines

The interest in contrast-medium-induced nephropathy has increased considerably during the last few years. Various guidelines regarding identifying patients at risk and measures to reduce the incidence of this complication have been proposed. The aim of this review was to analyse whether there is some consistency amongst these guidelines. A Medline search for the keyword "contrast medium induced nephropathy" during the period from the beginning of 2003 through the end of September 2005 was carried out. Only papers in English were reviewed. Thirteen guidelines were identified. Inconsistency was observed regarding advise on the prophylactic use of drugs and the isoosmolar dimer to reduce the incidence of contrast-medium-induced nephropathy. Consistency was found in relation to the importance of hydration, cessation of intake of nephrotoxic drugs and administration of the lowest possible dose of contrast medium. No new consensus has been observed in comparison to the European Society for Urogenital Radiology (ESUR) guidelines, which were published in 1999.