Risk factors for contrast-induced nephropathy

Low KeV virtual monoenergetic images for detecting low dose iodine- or alternative Gd-based IV contrast agents

Background

The recent shortage of iodine-based intravenous contrast and its cost highlight the need for limiting dose and alterative agents.

Purpose

To quantify radiodensity (Hounsfield Units, HU) improvement and potential iodine dose reduction with low keV imaging compared to conventional polyenergetic reconstructions on dual source (DSCT) and dual layer (DLCT) CT and to assess potential utility of non-iodine gadolinium-alternatives with low keV imaging.

Materials and methods

This phantom study used dilutions of three commercially-available contrast agents scanned by DSCT and DLCT. Conventional polyenergetic and virtual monoenergetic images (VMI) were reconstructed of each of five dilutions at five keV levels. HU and signal-to-noise ratios were compared among iodine- and gadolinium-based contrast agents.

Results

Iodine- and gadolinium-based contrast agent HU increased inversely to keV for the same dilution in both scanners. At the lowest keV setting (40 keV), iodine-based contrast agent HU in VMIs with DLCT and DSCT were approximately 300 % and 400 % of conventional, respectively. Gd-based contrast agent HU in VMIs at low keV were similar to or better than conventional iodine HU. Comparing the dual energy CTs, although HU from iodine and gadolinium-based contrast agents for conventional polyenergetic reconstructions was similar, HU in VMIs of DSCT were right shifted compared to DLCT by ∼10 keV lower.

Conclusion

Depending on CT scanner type, 1/3 to 1/4 dose of iodinated contrast at 40 keV provides HU similar to full dose conventional acquisition, suggesting 1/3-1/4 dose may be adequate clinically at 40 keV. Depending on the Gd-based contrast and CT type, Gd-based contrast at 40 keV provides similar or greater HU compared to conventional acquisitions with iodinated contrast, suggesting Gd-based contrast at 40 keV may serve as an alternative to iodinated contrast. HU on VMI images is scanner dependent, suggesting scanner-dependent protocol optimization and potentially monoenergy HU calibration between scanners is needed.

Association of random glucose to albumin ratio with post-contrast acute kidney injury and clinical outcomes in patients with ST-elevation myocardial infarction

Purpose

Both glucose and albumin are associated with chronic inflammation, which plays a vital role in post-contrast acute kidney injury (PC-AKI). To explore the relationship between random glucose to albumin ratio (RAR) and the incidence of PC-AKI after percutaneous coronary intervention (PCI) in patients with ST-elevation myocardial infarction (STEMI).

Patients and methods

STEMI patients who underwent PCI were consecutively enrolled from January, 01, 2010 to February, 28, 2020. All patients were categorized into T1, T2, and T3 groups, respectively, based on RAR value (RAR < 3.377; 3.377 ≤ RAR ≤ 4.579; RAR > 4.579). The primary outcome was the incidence of PC-AKI, and the incidence of major adverse clinical events (MACE) was the second endpoint. The association between RAR and PC-AKI was assessed by multivariable logistic regression analysis.

Results

A total of 2,924 patients with STEMI undergoing PCI were finally included. The incidence of PC-AKI increased with the increasing tertile of RAR (3.2% vs 4.8% vs 10.6%, P<0.001). Multivariable regression analysis demonstrated that RAR (as a continuous variable) was associated with the incidence of PC-AKI (adjusted odds ratio (OR) =1.10, 95% confidence interval (CI) =1.04 - 1.16, P<0.001) and in-hospital MACE (OR=1.07, 95% CI=1.02 - 1.14, P=0.012); RAR, as a categorical variable, was significantly associated with PC-AKI (T3 vs. T1, OR=1.70, 95% CI=1.08 - 2.67, P=0.021) and in-hospital MACE (T3 vs. T1, OR=1.63, 95% CI=1.02 - 2.60, P=0.041) in multivariable regression analyses. Receiver operating characteristic curve analysis showed that RAR exhibited a predictive value for PC-AKI (area under the curve (AUC)=0.666, 95% CI=0.625 - 0.708), and in-hospital MACE (AUC= 0.662, 95% CI =0.619 - 0.706).

Conclusions

The high value of RAR was significantly associated with the increasing risk of PC-AKI and in-hospital MACE after PCI in STEMI patients, and RAR offers a good predictive value for those outcomes.

Prevalence of contrast-induced nephropathy after primary percutaneous coronary intervention at a tertiary referral hospital

Objective

This study aimed to quantify the incidence of Contrast-induced nephropathy (CIN) in patients undergoing primary percutaneous coronary intervention (PPCI) due to acute ST-elevation myocardial infarction (STEMI).

Methods

From April 2019 to March 2022, a prospective, observational study enrolled 213 consecutive STEMI patients referred to a tertiary hospital for PPCI. Participants were divided into tow groups based on the presence or absence of contrast-induced nephropathy. The chi-square test (χ2) and Student's t-test evaluated the data, with logistic regression identifying CIN's independent predictors.

Results

Results: In this study, the incidence of contrast-induced nephropathy was observed at 13.1% (N = 28). Several factors were more prevalent among patients exhibiting contrast-induced nephropathy. These factors encompassed: radial access for coronary angiography over the femoral method (P = 0.021), elevated contrast volume (P = 0.003), smoking (P = 0.009), diabetes (P = 0.04), heart failure (P = 0.049), a history of coronary artery bypass graft (P = 0.006), diminished left ventricular ejection fraction indicating systolic dysfunction (P = 0.012), cardiogenic shock (P = 0.046), increased BUN at the time of admission (P = 0.043), decreased initial GFR (P = 0.004), and prior consumption of medications such as aspirin (P = 0.002), diuretics (P = 0.046), beta blockers (P = 0.04), angiotensin-converting enzyme inhibitors (P = 0.033), angiotensin receptor blockers (P = 0.02). Other relevant conditions included anemia (P = 0.012), leukocytosis (P = 0.011), hypercholesterolemia (P = 0.034), and reduced HDL levels (P = 0.004).Through logistic regression, key predictors for the onset of contrast-induced nephropathy were determined, which included heart failure (OR: 5.52; 95% CI: 1.08-28.24), radial access (OR: 12.71; 95% CI: 1.45-110.9), hypercholesterolemia (OR: 1.02; 95% CI: 1.004-1.04), increased BUN upon admission (OR: 1.11; 95% CI: 1.006-1.24), and leukocytosis (OR: 2.03; 95% CI: 1.18-3.49).

Conclusions

While heart failure, radial access, hypercholesterolemia, elevated BUN at admission, and leukocytosis significantly influenced renal filtration deterioration post-PPCI, it's evident that CIN is multifactorial. Further studies are crucial to elucidate the underlying factors.

Investigating the Prevalence of Contrast-associated Nephropathy and the Related Risk Factors in Patients Undergoing Elective Angioplasty

Objective

Contrast-associated nephropathy (CAN) is a sudden decrease in kidney function following contrast media administration. Considering the importance of CAN in the patient's outcome and the high prevalence of this complication in cardiac catheterizing centers, this study was designed to investigate the prevalence and the related risk factors of CAN in patients undergoing angioplasty in Chamran Heart Hospital, Isfahan, Iran, from January 2022 to June 2022.

Methods

The inclusion criteria were adult patients above 18 admitted for elective percutaneous coronary intervention (PCI). Patient demographic information, underlying diseases and medications, dehydration state, type and amount of contrast media, and serum levels of blood urea nitrogen (BUN) and serum creatinine (SrCr) at 24 and 72 h after contrast injection were all recorded.

Findings

Out of 340, 128 patients developed CAN after PCI, giving an incidence of 37.64%. Adjusted analysis showed a significant relation between age over 65, the amount of contrast media administered, and the use of furosemide with the incidence of CAN. However, adjusted logistic regression analysis failed to show any significant relationship between the risk of CAN and the hydration status of the patients at 24 and 48 h after receiving contrast media as diagnosed by BUN/SrCr >20.

Conclusion

The prevalence of CAN in this study was higher than in other studies since this high-risk population was under risk factors such as arterial injection of contrast material and a higher amount of contrast material administration. In addition, advanced age, volume of contrast material, and previous or concurrent furosemide administration were associated with an increased risk of CAN.

Low Tube Voltage Chest Computed Tomography With Enhancement Using Low-Concentration Iodinated Contrast Media: Comparison of 240 mg/mL Versus 300 mg/mL Iodinated Contrast Media

Purpose: To evaluate the image quality of low voltage chest computed tomography with enhancement (CECT) using low-concentration-iodine contrast media (LCCM). Method: From 9 December to 19 December 2019, three different protocols were used for 263 patients undergoing chest CECT. Chest CECT was done using routine (300 mgI/ml contrast media with 100 kVp) protocol (group 1), LCCM (240 mgI/ml contrast media)-100 kVp protocol (group 2) and LCCM-80 kVp protocol (group 3) in 91, 97 and 75 patients, respectively. The overall diagnostic acceptability, anatomical depiction, noise and contrast-related artifacts were assessed. Additionally, the mean attenuation, signal-to-noise ratio (SNR), contrast-to-noise ratio (CNR) and figure of merit (FOM) in the aorta and the main pulmonary trunk were measured. Results: The overall diagnostic acceptability scores were not significantly different between groups 1 and 2 (P = .261); group 3 demonstrated significantly lower overall diagnostic acceptability score compared with group 1 (P = .011) or group 2 (P < .001). However, in CECT with iterative reconstruction (IR), the overall diagnostic acceptability scores did not show significant difference among 3 groups. Group 3 showed significantly lower effective radiation dose compared with group 1 (2.33 vs 1.22 mSv, P < .001) or group 2 (2.28 vs .22 mSv, P < .001). Conclusions: In 100 kVp chest CECT, the image quality of using 240 mg/mL iodinated contrast media is comparable to that using 300 mg/mL iodine contrast media, regardless of application of IR; with IR, chest CECT using 80 kVp and 240 mg/mL iodinated contrast media results in acceptable image quality and lower radiation dose.

NT-proBNP as a Predictive Biomarker for Contrast-Induced Nephropathy in ACS Patients Undergoing Coronary Angiogram – An Observational Study

Objectives:

1. To assess the value of baseline NTproBNP at admission and to determine the levels of serum creatinine at 48 hours and 72 hours after procedure for evidence of contrast-induced nephropathy (CIN) for patients undergoing CAG. 2. To evaluate the relationship between the values of NTproBNP and evidence of CIN.

Materials and Methods:

This is an observational study performed between June 2021-November 2021 at Nizams Institute of Medical Sciences in 75 patients diagnosed with ACS. we assessed the role of nt pro bnp as a predictive biomarker for diagnosis of contrast induced nephropathy in patients of ACS undergoing coronary angiography. Serum creatinine is repeated at 48 h post procedure and compared to baseline.

Results:

Spearman’s correlation test was used to assess the correlation between NT-proBNP values and ejection fraction on the 2D echo. The rho value (-0.69) was suggestive of a strong negative correlation. P value & lt; 0.001 making it statistically significant. Simple linear regression analysis was used to predict the NT-proBNP levels by ejection fraction percentage among study patients, it showed that, for every 1% decrease in ejection fraction, the NT-proBNP levels will significantly increase by 102.90 pg/mL at P and lt; 0.001. Wilcoxon Signed Rank test was used to compare the baseline serum creatinine values with 48/72 h serum creatinine values after undergoing angiography with contrast, incidence of acute kidney injury (AKI) as shown by the resulting P value was and lt; 0.001, thus statistically significant. The ROC curve analysis to establish the association between NT-proBNP as a marker for incidence of AKI (CIN) shows shows that, NT-proBNP cut off and gt;1670 pg/mL has a sensitivity of 81.82% and specifity of 98.44% and is statistically significant with P value and lt; 0.001.

Conclusion:

It was observed that NT-proBNP >1670 pg/mL prior to the procedure, was significantly associated with the risk of development of contrast induced nephropathy. Measurement of serum NT-proBNP pre procedure aids in identifying at risk population for developing CIN.

Prevention and Management of AKI in ACS Patients Undergoing Invasive Treatments

PURPOSE OF REVIEW

Management of patients presenting with acute coronary syndrome (ACS) includes invasive procedures that may increase the risk of acute kidney injury (AKI). AKI adversely affects the outcomes of such procedures and complicates the management of ACS. We have summarized several strategies for the prevention and management of AKI in this critical patient group including in the pre-procedural, intraprocedural, and post-procedural settings.

RECENT FINDINGS

Definitive prevention and management strategies for AKI in patients presenting with ACS requiring invasive management can be confounded by the variation in data outcomes. Pre-procedural hydration with normal saline when accounting for time to catheterization, radial artery access, contrast stewardship, and close monitoring of renal function after catheterization should be implemented.

Serum Level of Complement C1q is Associated with Contrast-Associated Acute Kidney Injury in Patients Undergoing Emergency Percutaneous Coronary Intervention

Background

As an inflammatory factor, complement C1q is related to the prevalence and progression of atherosclerosis; however, in patients undergoing emergency percutaneous coronary intervention (PCI), it is unclear whether C1q is related to the prevalence of contrast-associated acute kidney injury (CA-AKI).

Methods

From November 2018 to March 2021, 1182 patients who underwent emergency PCI were continuously recruited. Patients were divided into CA-AKI group (n = 234) and non-CA-AKI group (n = 948). CA-AKI was defined as an increase in serum creatinine from the baseline level (≥25% or ≥0.5 mg/dL) 48–72 hours after contrast exposure. All subjects were tested for serum C1q levels when they were admitted to the hospital.

Results

Among the 1182 patients undergoing emergency PCI, 234 patients (19.80%) developed CA-AKI. The level of preoperative serum complement C1q in the CA-AKI group was significantly higher than that in the non-CA-AKI group. Logistic regression and restricted cubic spline analyses showed that the incidence of CA-AKI was positively associated with the serum C1q level pre-PCI. Univariate and multivariate logistic regression analyses showed that C1q was an independent predictor of whether CA-AKI occurred after emergency PCI. The area under the curve (AUC) of the C1q was 0.703 [95% confidence interval (CI) 0.667–0.739] in patients receiving emergency PCI. CA-AKI model included the following three predictors: C1q, eGFR, and IABP use. The AUC of forecast probability was 0.718 [95% CI 0.682–0.754].

Conclusion

In patients receiving emergency PCI procedure, a high C1q level before PCI is associated with the increased risk of CA-AKI.

Imaging Modalities for Evaluation of Intestinal Obstruction

It is essential for the colon and rectal surgeon to understand the evaluation and management of patients with both small and large bowel obstructions. Computed tomography is usually the most appropriate and accurate diagnostic imaging modality for most suspected bowel obstructions. Additional commonly used imaging modalities include plain radiographs and contrast imaging/fluoroscopy, while less commonly utilized imaging modalities include ultrasonography and magnetic resonance imaging. Regardless of the imaging modality used, interpretation of imaging should involve a systematic, methodological approach to ensure diagnostic accuracy.

Magnitude and associated factors of contrast induced nephropathy among patients undergoing coronary angiography and interventions at a cardiac referral hospital in Tanzania - a cross-sectional study

Introduction

contrast media are increasingly used in diagnostic and interventional procedures but are also known causes of acute kidney injury - a condition known as contrast induced nephropathy (CIN). We aimed to determine the magnitude and associated factors of CIN among patients undergoing coronary angiography and percutaneous coronary intervention at a cardiac referral hospital in Tanzania.

Methods

all adult patients undergoing elective coronary angiography and percutaneous coronary intervention at Jakaya Kikwete Cardiac Institute were consecutively enrolled between August 2017 and January 2018, if they fulfilled the inclusion criteria. Pre-procedure, 24- and 72-hours' post procedure serum creatinine was measured. CIN was defined as increase of ≥25% or absolute increase of ≥44μmol/L of serum creatinine within 72 hours following exposure to contrast media. Data analysis were done using SPSS Version 20. P-value of <0.05 was considered statistically significant.

Results

in total, 210 (94.6%) out of 222 patients seen during the study period fulfilled the inclusion criteria and were enrolled. Their mean (SD) age was 61.3 (10.9) years and 64.3% were men. Hypertension, diabetes, smoking and alcohol consumption was present in 86.7%, 37.7%, 12.4% and 37.6% respectively. The incidence of CIN was 19% within 72 hours post procedure. On multivariate logistic regression analysis, independent factors for developing CIN were history of heart failure (aOR=7.34), central obesity (aOR=3.12), triple vessel disease (aOR=10.14) and post procedure stay of ≥3 days (aOR=4.1), all p<0.05.

Conclusion

the incidence of CIN found in this population is high (19%) and is associated with heart failure, obesity, multi-vessel disease and longer post-procedure hospital stay.

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

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

Imaging in chronic pancreatitis: State of the art review

Chronic pancreatitis (CP) is an important gastrointestinal cause of morbidity worldwide. It can severely impair the quality of life besides life-threatening acute and long-term complications. Pain and pancreatic exocrine insufficiency (leading to malnutrition) impact the quality of life. Acute complications include pseudocysts, pancreatic ascites, and vascular complications. Long-term complications are diabetes mellitus and pancreatic cancer. Early diagnosis of CP is crucial to alter the natural course of the disease. However, majority of the cases are diagnosed in the advanced stage. The role of various imaging techniques in the diagnosis of CP is discussed in this review.

Inferior vena cava assessment can predict contrast-induced nephropathy in patients undergoing cardiac catheterization: A single-center prospective study

BACKGROUND

Contrast-induced nephropathy (CIN) following cardiac catheterization remains a considerable clinic challenge. Volume status is very important in the development of CIN. It can be assessed noninvasively by measuring inferior vena cava (IVC) diameters. The aim of this study was to assess whether IVC can be used for prediction of CIN in patient undergoing cardiac catheterization.

METHODS

A total of 269 patients undergoing cardiac catheterization were prospectively enrolled in this study. IVC inspiratory and expiratory diameters were measured by transthoracic echocardiography. Caval index was calculated as the percentage decrease in the IVC diameter during respiration. CIN was defined as a ≥0.5 mg/dL and/or a ≥25% increase in serum creatinine within 72 hour post-procedure.

RESULTS

Contrast-induced nephropathy developed in 46 (17.1%) patients after cardiac catheterization. Caval index was significantly higher in patients with CIN than in patients without CIN (47% [40-64] vs 35% [26-50], P < 0.001). In addition, the used contrast volume (145 [90-217] vs 70 [60-100], P < 0.001) and the frequency of percutaneous coronary intervention (50% vs 17.9%, P < 0.001) were significantly higher in patients with CIN than in patients without CIN. In receiver operating characteristic (ROC) curve analysis, caval index ≥ 41% predicted CIN with a specificity of 69% and sensitivity of 72%. Multivariate analysis indicated that caval index ≥ 41% was an independent predictor of post-procedural CIN development (OR: 3.367, 95% CI: 1.574-7.203, P = 0.002).

CONCLUSIONS

Caval index, a simple and noninvasive echocardiographic marker, is an independent predictor of post-procedural CIN development in patients undergoing cardiac catheterization.

Contrast-induced Nephropathy Following Percutaneous Coronary Intervention at a Tertiary Cardiac Center in Nepal

Background

Contrast-induced nephropathy (CIN) is one of the leading causes of morbidity and mortality including increased financial burden in high risk patients undergoing percutaneous coronary intervention (PCI).

Methods

This is an observational prospective study. We aimed to study the incidence of CIN in Nepalese populations and compare the outcome to international reprinted values with coronary artery disease (CAD) undergoing PCI. All consecutive patients with CAD undergoing PCI between February 2010 and July 2010 were enrolled in the study.

Results

One hundred fifty-two patients were enrolled in the study during six months period. Twenty (13.20%) patients developed CIN following PCI. Out of them 70% were diabetics and 30% were non-diabetics. Mean age of patients was 58.5 ± 23 years; male:female ratio was 2.7:1. Mean contrast volume injected was 160.3  ±  78.3  mL. Diabetic patients 21.8% (14/64) had significant CIN compared to non-diabetic patients 6.8% (6/88) following PCI (<0.01).

Conclusions

CIN is a common complication following PCI especially in diabetics. Despite the use of iodinated material we had similar incidence of CIN comparing the incidence of CIN among various radiocontrast compounds used to visualize vessels. None of the patients received hemodialysis as compared to available studies and there was no observed mortality.

Contrast Media-Induced Nephropathy in Patients with Unruptured Cerebral Aneurysm After Coiling Endovascular Treatment

BACKGROUND

The endovascular coiling procedure to treat cerebral aneurysms using contrast media has become more popular. However, studies of the incidence of, and risk factors for, contrast media-induced nephropathy (CIN) after coiling procedures have been limited. Thus, we evaluated the incidence and risk factors for CIN in patients who had undergone cerebral aneurysmal coiling procedures.

METHODS

We retrospectively reviewed the electric medical records of 380 patients who had undergone cerebral aneurysmal coiling treatment under general anesthesia. CIN was defined as an absolute increase in serum creatinine (≥0.5 mg/dL) or a relative increase (≥25%) in the baseline serum creatinine value at 48-72 hours after exposure to a contrast agent.

RESULTS

Elective cerebral aneurysmal coiling procedures were performed in 230 patients. Of the 230 patients, CIN developed in 13 (5.6%). The presence of diabetes mellitus (30.8% vs. 9.7%; P = 0.040) and patient age >75 years (30.8% vs. 6.5%; P = 0.012) were risk factors for CIN.

CONCLUSIONS

Our study has demonstrated that the incidence of CIN in patients undergoing elective cerebral aneurysmal coiling procedures is ∼6.0%. We also identified underlying diabetes mellitus and advanced age (≥75 years) as potential risk factors.

Prognostic Value of Improved Kidney Function After Transcatheter Aortic Valve Implantation for Aortic Stenosis

Transcatheter aortic valve implantation (TAVI) is associated with acute kidney injury (AKI), but can also improve the kidney function (IKF). We assessed the effects of kidney function changes in relation to baseline kidney function on 2-year clinical outcomes after TAVI. In total, 639 consecutive patients with aortic stenosis who underwent TAVI were stratified into 3 groups according to the ratio of serum creatinine post- to pre-TAVI: IKF (≤0.80; n = 95 [15%]), stable kidney function (0.80 to 1.5; n = 477 [75%]), and AKI (≥1.5; n = 67 [10%]). Different AKI risk scores were compared using receiving-operator characteristics. Median follow-up was 24 (8 to 44) months. At 3 months, the increase in estimated glomerular filtration rate in the IKF group remained, and the decreased estimated glomerular filtration rate in the AKI group recovered. Compared with a stable kidney function, AKI showed a higher 2-year mortality rate (adjusted hazard ratio [HR] 3.69, 95% confidence interval [CI] 2.43 to 5.62) and IKF a lower mortality rate (adjusted hazard ratio 0.53, 95% CI 0.30 to 0.93). AKI also predicted major and life-threatening bleeding (adjusted odds ratio 2.94, 95% CI 1.27 to 6.78). Independent predictors of AKI were chronic kidney disease and pulmonary hypertension. Independent predictors of IKF were female gender, a preserved kidney function, absence of atrial fibrillation, and hemoglobin level. Established AKI risk scores performed moderately and did not differentiate between AKI and IKF. In conclusion, AKI is transient and is independently associated with a higher mortality rate, whereas IKF is sustained and is associated with a lower mortality rate. These effects are independent of baseline kidney function. Further studies are warranted to investigate the role of IKF and generate a dedicated prediction model.

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.

Expression of neutrophil gelatinase-associated lipocalin in low osmolar contrast-induced nephropathy in rats and the effect of N-acetylcysteine

Serum creatinine (Scr), which is a conventional indicator of contrast-induced nephropathy (CIN), is unable to reflect the damage of kidney promptly. The present study aimed to investigate the value of neutrophil gelatinase-associated lipocalin (NGAL) in kidney and serum of CIN rats to observe whether NGAL can be used as a superior indicator of CIN. Furthermore, N-acetylcysteine (NAC) was used to assess its effect on CIN. A total of 120 adult male Sprague Dawley rats were randomly divided into four groups (n=30/group): CIN rats (CIN), normal rats treated with NAC (NAC), CIN rats treated with NAC (NAC+CIN) and the control group (CON). Serum Scr and NGAL values were measured at 2, 12, 24, 48 and 72 h following the procedure. Immunohistochemistry and western blot analysis were used to detect NGAL within the kidney tissue. Hematoxylin and eosin staining were used to access the renal injury score. Oxidative stress within the kidney was analyzed via malondialdehyde (MDA) and superoxide dismutase (SOD). The level of NGAL in the serum and tissue of the CIN group increased significantly 2 h after the procedure (P<0.05). However, the Scr value did not exhibit a significantly change until 48 h later. Based on the renal injury scores, NAC reduced the kidney damage caused by the contrast. NAC treatment was associated with a decrease in SOD levels and an increase in MDA. These findings suggested that NGAL was a superior indicator of CIN than Scr, as NGAL was able to detect kidney damage much earlier. Furthermore, NAC treatment inhibited oxidative stress, thus protecting against CIN.

Impact of low hemoglobin on the development of contrast-induced nephropathy: A retrospective cohort study

An increase in the use of iodinated contrast media, such as iohexol, iodixanol, iopamidol and iopromide, occasionally causes contrast-induced nephropathy (CIN) in patients undergoing coronary angiography (CAG) and/or percutaneous coronary intervention (PCI). The present study aimed to assess the effects of low levels of hemoglobin on the development of CIN in patients with normal renal function following CAG/PCI. A total of 841 consecutive patients undergoing CAG/PCI were divided into two groups: Patients with low levels of hemoglobin (male, <120 g/l; female, <110 g/l; n=156) and normal levels of hemoglobin (male, 120-160 g/l; female, 110-150 g/l; n=685). Multiple logistic regression analysis was performed to identify risk factors for CIN, which developed in 14.7% of patients with low levels of hemoglobin (relative risk, 3.07) and 5% of patients with normal levels of hemoglobin (P<0.01). Independent risk factors for developing CIN in patients with low levels of hemoglobin were a contrast media volume ≥200 ml, diuretic usage, low levels of hemoglobin and diabetes mellitus. For the patients with normal hemoglobin levels, the independent risk factors for developing CIN were a contrast media volume ≥200 ml and diuretic usage. The change in serum creatinine in patients with low levels of hemoglobin was significantly greater compared with patients with normal levels of hemoglobin (7.35±22.60 vs. 1.40±12.00; P<0.01). A similar incidence of developing CIN was observed when patients were administered each type of contrast media: Iohexol, iodixanol, iopamidol and iopromide. The optimal cut-off point at which the serum hemoglobin concentration resulted in a high probability of developing CIN was determined as 111.5 g/l in females and 115.5 g/l in males. In conclusion, low levels of hemoglobin were observed to be an independent risk factor for developing CIN. Patients with reduced hemoglobin levels should, therefore, be closely monitored prior to, and during, the administration of iodinated contrast media.

Effects of iodinated contrast agents on renal oxygenation level determined by blood oxygenation level dependent magnetic resonance imaging in rabbit models of type 1 and type 2 diabetic nephropathy

Background

To evaluate the effects of contrast agents containing increasing concentrations of iodine on the renal oxygenation level determined by blood oxygenation level dependent (BOLD) magnetic resonance imaging (MRI) in a rabbit model of diabetic nephropathy.

Methods

BOLD-MRI was performed using saline or iodinated (I) contrast agents (200, 240, 300, 350 and 400 mg I/mL) at 1, 24, 48, and 72 h after experimentally inducing type 2 diabetic nephropathy in rabbits. Differences in renal oxygenation levels between type 1 and type 2 diabetic nephropathy were also assessed by BOLD-MRI after injecting 400 mg I/mL of contrast agent.

Results

Contrast agents increased the R2* values of the renal cortex, outer medulla, and inner medulla to the maximum levels at 24 h. The R2* values then decreased to their lowest levels at 72 h. The R2* was highest following injection of 400 mg I/mL, especially in the outer medulla. The R2* values were not significantly different between types 1 and 2 diabetic nephropathy.

Conclusions

Iodinated contrast agents had the greatest influence on renal outer medulla oxygenation level at 24 h in type 2 diabetic nephropathy, with the greatest effects observed at the 400 mg I/mL dose level. There were no differences in BOLD-MRI values between type 1 and type 2 diabetic nephropathy after administering the contrast agent at 400 mg I/mL.

Geriatric chest imaging: when and how to image the elderly lung, age-related changes, and common pathologies

Even in a global perspective, societies are getting older. We think that diagnostic lung imaging of older patients requires special knowledge. Imaging strategies have to be adjusted to the needs of frail patients, for example, immobility, impossibility for long breath holds, renal insufficiency, or poor peripheral venous access. Beside conventional radiography, modern multislice computed tomography is the method of choice in lung imaging. It is especially important to separate the process of ageing from the disease itself. Pathologies with a special relevance for the elderly patient are discussed in detail: pneumonia, aspiration pneumonia, congestive heart failure, chronic obstructive pulmonary disease, the problem of overlapping heart failure and chronic obstructive pulmonary disease, pulmonary drug toxicity, incidental pulmonary embolism pulmonary nodules, and thoracic trauma.

Incidence and Main Determinants of Contrast-Induced Nephropathy following Coronary Angiography or Subsequent Balloon Angioplasty

BACKGROUND/AIMS

Patient assessment by imaging studies using contrast media is currently replacing open procedures, especially in high-risk patients. However, the use of such contrast media might result in acute events and injuries after the procedure. In the present study, we first determined the incidence of contrast-induced nephropathy (CIN) in a sample of Iranian patients who candidated for coronary angiography and/or angioplasty, and then assessed major risk factors predicting the appearance of CIN following these procedures.

METHODS

Two hundred and fifty consecutive, eligible patients scheduled for coronary angiography and/or angioplasty at the Afshar Hospital in Yazd between January 2009 and August 2010 were considered for enrollment. Renal function was measured at baseline and 48 h after the intervention, and CIN was defined by an increase in creatinine of >0.5 mg/dl or 25% of the initial value. The predictive role of potential risk factors was determined in a multivariate model adjusted for comorbidities, preexisting renal impairment, and angiographic data.

RESULTS

CIN following coronary angiography or angioplasty appeared in 12.8% of the cases. A myocardial infarction before the procedure (OR = 2.121, p = 0.036) and a prior history of hypertension (OR = 2.789, p = 0.025) predicted the appearance of acute renal failure following angiography or subsequent angioplasty. A low estimated glomerular filtration rate at baseline slightly predicted CIN after these interventions.

CONCLUSION

Transient acute renal dysfunction occurred in 12.8% of the patients within 48 h after angiography or subsequent angioplasty and could be predicted by a myocardial infarction before the procedure or by a prior history of systolic hypertension.

Aged rats are susceptible to nephrotoxicity induced by iodinated contrast media

OBJECTIVE

The objective of this study is to evaluate the effect and mechanism of aging on iodinated-contrast-media-induced nephropathy in male rats.

METHODS

Twenty-four healthy male rats were initially divided into 12-month-old and 24-month-old age groups (adult and older age groups, respectively; n = 12/group); subsequently, each age group was randomly divided into saline control (NS) and contrast media (CM) groups (n = 6/group). CM (76% diatrizoate, 10 mL/kg b.w.) was given through the caudal vein. Urinary creatinine (Ucr) and serum creatinine (Scr) were detected by an automatic biochemical analyzer. The activities of renal malondialdehyde (MDA), superoxide dismutase (SOD), angiotensin-converting enzyme (ACE), angiotensin II (Ang II), and reduced form of nicotinamide adenine dinucleotide phosphate oxidase (NADPH oxidase) were determined by spectrophotometric assays with commercially available kits according to the manufacturers' protocols. Renal histological changes were observed by hematoxylin and eosin staining and scored semiquantitatively.

RESULTS

In diatrizoate-injected aged rats, Scr, the activities of ACE, Ang II, MDA, and NADPH oxidase in renal tissues were significantly increased (p < 0.01). The histologic scores were higher in the aged animals with CM treatment than those of control or adult rats (p < 0.01). There was an increasing trend but no significant statistical difference in renal ACE, Ang II, MDA, and NADPH oxidase or histologic scores in adult CM-injected rats compared with control animals (p > 0.05).

CONCLUSIONS

Older age is an aggravating factor of iodinated-contrast-media-induced nephropathy in male rats. Oxidative stress and the renin-angiotensin system (RAS) may play an important role in nephrotoxicity induced by iodinated contrast media, especially in aged male rats.

How to reduce nephropathy following contrast-enhanced CT: a lesson in policy implementation

In excess of 50 contrast-enhanced computed tomography (CT) examinations are typically undertaken in our tertiary hospital NHS Trust each weekday, approximately 13,000 each year. In the Department of Radiology alone, we inject more than 1300 l of iodinated contrast medium per annum. There is a real need to devise a policy to anticipate contrast medium-induced nephropathy (CIN) and minimize its effects, without disrupting the high-intensity CT service. Having written a comprehensive yet pragmatic policy to reduce the incidence of this iatrogenic condition, it seemed sensible to share it with the wider radiology community and share the experience and lessons learnt in engaging all the stakeholders, ushering in the change with as little fuss as possible. The ramifications on primary and secondary care had to be anticipated, resource implications managed, and staff trained. This review is therefore presented in four sections: framing the problem, assessing its size and nature; a succeeding section on the available guidelines and their uptake; the policy itself to reduce CIN in CT is presented in the third section; and crucially, a description of the policy introduction process in the last section.

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.

Is angiotensin-converting enzyme inhibitor a contraindication for contrast-induced nephropathy prophylaxis? A review about its paradox

Contrast-induced nephropathy (CIN) is reported to be the third leading cause of acute renal failure. The role of angiotensin-converting enzyme (ACE) inhibitors in CIN is controversial. Some studies pointed out that it was effective in the prevention of CIN, while some concluded that it was associated with increased risk of CIN, especially for patients with preexisting renal impairment. Nevertheless, it is a common practice in many centers to prescribe ACE inhibitors before coronary angiography. The most likely mechanisms leading to CIN are medullary hypoxia due to decreased renal blood flow (RBF) secondary to renal artery vasoconstriction and direct tubular toxicity by contrast medium (CM). Furthermore, experimental data suggest that an activated renin-angiotensin-aldosterone system, increased endothelin-1, and reactive oxygen species play a role in the pathogenesis of CIN and these can be inhibited by using ACE inhibitors. In this context, we review the medical literatures and discuss the pathogenesis, the role of renin-angiotensin-aldosterone system on the development of CIN and ACE inhibitors' effect on CIN.

Comparison of risk factors for contrast-induced acute kidney injury between patients with and without diabetes

Although it is well known that diabetics are at a higher risk of contrast-induced acute kidney injury (CI-AKI) than nondiabetic patients, the reason for this discrepancy is not well known. Thus, in this study, we compared the predisposing factors for CI-AKI between patients with and without diabetes. We prospectively studied 290 consecutive in-hospital patients including 88 diabetics undergoing coronary angiography or a percutaneous coronary intervention in Kowsar hospital, and we compared risk factors for CI-AKI between diabetic and nondiabetic patients. CI-AKI was defined as RIFLE criteria within 48 hours after contrast exposure. The incidence of CR-AKI was significantly higher in diabetic patients compared with nondiabetics (P<0.05). The incidence of CI-AKI was significantly higher in patients with diabetes and left-ventricular ejection fraction ≤40%, hypercholesterolemia, serum creatinine ≥1.1 mg/dL, estimated glomerular filtration rate (eGFR) <90 mL/min, Contrast volume ≥80 (mL), maximum safe contrast volume factor of 1.5, and dehydration, while in nondiabetics, a significantly higher incidence of CR-AKI was observed in those with serum creatinine ≥1.1 mg/dL (P=0.02) and/or eGFR<60 mL/min (P=0.01). Multiple logistic regression analysis showed hyperchlosteremia to be the strongest predictor of AKI (P=0.01, B:14.5) in diabetics, followed by eGFR<90 (P=0.05, B:12.4) but, in nondiabetics, only eGFR<60 predicted the occurrence of CI-AKI (P=0.04, B:2.3). It seems that the predisposing factors to CI-AKI differ in diabetics and nondiabetics. In patients with diabetes, hypercholesterolemia is the strongest predictor of CI-AKI, followed by eGFR and diabetics are at risk for CI-AKI in the early stage of chronic kidney disease (stage 2), accounting for the higher incidence of CI-AKI in them.

Advanced imaging of chronic pancreatitis

Chronic pancreatitis is characterized by continuing inflammation, destruction, and irreversible morphological changes in the pancreatic parenchyma and ductal anatomy. These changes lead to chronic pain and/or loss of function. Although these definitions are simple, the clinical diagnosis of chronic pancreatitis remains difficult to make, especially for early disease. Routine imaging modalities such as transabdominal ultrasound and standard CT scans are insensitive for depicting early disease, and detect only advanced chronic pancreatitis. Advances in imaging modalities including CT, MRI with gadolinium contrast enhancement, MRI with magnetic resonance cholangiopancreatography (MRI/MRCP), MRI/MRCP with secretin-stimulation (S-MRCP), endoscopic retrograde cholangiopancreatography (ERCP), and endoscopic ultrasound (EUS) allow earlier diagnosis of chronic pancreatitis. This article reviews the recognized findings, advantages, and disadvantages of the various imaging modalities in the management of chronic pancreatitis, specifically CT, MRI with or without MRCP and/or S-MRCP, ERCP, and EUS.

Periprocedural hemoglobin drop and contrast-induced nephropathy in percutaneous coronary intervention patients

Background and Objectives

The development of contrast-induced nephropathy (CIN) is associated with an increased risk of death and late cardiovascular events after percutaneous coronary intervention (PCI). The relationship between CIN and hemoglobin drop has been controversial. The aim of this study was to evaluate the clinical usefulness of periprocedural hemoglobin drop as a nontraditional risk factor for CIN.

Subjects and Methods

Five-hundred thirty-seven patients who underwent PCI were divided into 2 groups: Group I (486 patients: patients who did not develop CIN) and Group II (51 patients: patients who developed CIN). All patients were administered iodixanol as contrast media during coronary angiography. CIN is defined as a rise in serum creatinine of ≥25% or ≥0.5 mg/dL above the baseline value within 48 hours after contrast administration.

Results

Baseline clinical and cardiovascular risk factors were not significantly different between the two groups, except for low abdominal circumference (Group I : Group II=87.9±9.0 cm : 81.2±15.1 cm, p=0.024), body weight (Group I : Group II=63.5±10.6 kg : 59.7±9.2 kg, p=0.008), body mass index (BMI) (Group I : Group II=24.4±3.4 kg/m² : 23.4±2.8 kg/m², p=0.032), pre-PCI hemoglobin (Group I : Group II=13.2±2.0 g/dL : 12.3±2.0 g/dL, p=0.003), and post-PCI hemoglobin (Group I : Group II=12.4±1.9 g/dL : 11.5±1.8 g/dL, p=0.001). Multiple logistic regression analysis showed that a periprocedural drop in hemoglobin (>1 g/dL) was an independent predictor of CIN, like other known risk factors.

Conclusion

A periprocedural drop in hemoglobin of more than 1 g/dL is another important independent predictor for CIN, even in patients administered the lowest nephrotoxic contrast agent, iodixanol, during PCI.

Contrast-induced nephropathy in patients with type 2 diabetes during coronary angiography: risk-factors and prognostic value

AIMS

To determine risk factors, prognostic, value prevention of development of contrast-induced nephropathy (CIN) after percutaneous coronary intervention (PCI) in patients with type 2 diabetes mellitus (T2DM).

MATERIALS AND METHODS

We have retrospectively analyzed the incidence of CIN developed after PCI in 151 patients T2DM and 50 patients without diabetes. All patients were subjected to thorough clinical examination (including serum creatinine level before and 48 hours after intervention).

RESULTS

CIN developed more frequently after PCI in patients with T2DM than in patients of the same age without diabetes at the same baseline renal function, volume of contrast media and hydration status. The risk of developing CIN in patients with T2DM is associated with: heart failure, anemia, volume of contrast media, diuretics use in the peri-procedure period, multiple coronary artery disease, need of interventional procedures. TIDM patients with CIN had faster decline of renal function, more often developed cardiovascular diseases and had lower 24 month survival rate.

CONCLUSIONS

High risk of CIN development and its prognostic significance in patients with T2DM determine the necessity of individually evaluated risks for preventive measures during contrast media interventions.

Renal vascular imaging: ultrasound and other modalities

Sonographic evaluation of the genitourinary system is a fast, safe, and effective means to detect renal disease. In conjunction with other modalities, Doppler can depict a variety of abnormalities. However, optimization of Doppler techniques and a solid understanding of Doppler threshold criteria are critical for success, whether in the native or transplanted kidney.

Conflicting and new risk factors for contrast induced nephropathy

PURPOSE

Iodinated contrast medium is commonly used in diagnostic or interventional procedures in uroradiology. Procedures requiring the intravascular administration of iodinated contrast medium are becoming a great source of an iatrogenic disease known as contrast induced nephropathy. Identifying patients at high risk is the first step to minimize the overall risk of contrast induced nephropathy. This review describes conflicting and new risk factors for contrast induced nephropathy.

MATERIALS AND METHODS

A MEDLINE/PubMed search from 1966 to 2006 was performed. All articles related to the use of contrast medium and the risk factors for contrast induced nephropathy were reviewed.

RESULTS

The classic risk factors for contrast induced nephropathy are preexisting renal failure, diabetes mellitus, advanced age, nephrotoxic agent administration, hypovolemia, use of a large amount of contrast medium or an ionic hyperosmolar contrast medium and congestive heart failure. Metabolic syndrome, prediabetes and hyperuricemia have been identified as new risk factors for contrast induced nephropathy. The use of angiotensin-converting enzyme inhibitors and angiotensin II receptor blockers, renal transplantation, diabetes mellitus with normal renal function, low osmolar contrast medium in patients at high risk for contrast induced nephropathy, multiple myeloma, female gender and cirrhosis have been classified as conflicting risk factors for contrast induced nephropathy.

CONCLUSIONS

Patients at risk for contrast induced nephropathy should be identified before urological procedures requiring contrast administration. In addition to the classic risk factors for contrast induced nephropathy, determining the metabolic syndrome, hyperuricemia and prediabetes as well as the use of angiotensin-converting enzyme inhibitors and angiotensin II receptor blockers before performing procedures using contrast medium seems to be a useful guide to assess the risk of contrast induced nephropathy.