Contrast induced nephropathy in urology

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.

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

Purpose

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

Methods

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

Results

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

Conclusions

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

Prediction of contrast induced acute kidney injury using novel biomarkers following contrast coronary angiography

BACKGROUND/INTRODUCTION

Chronic kidney disease (CKD) is a risk factor for contrast induced acute kidney injury (CI-AKI). Contrast angiography in CKD patients is a common procedure. Creatinine is a delayed marker of CI-AKI and delays diagnosis which results in significant morbidity and mortality.

AIM

Early diagnosis of CI-AKI requires validated novel biomarkers.

DESIGN

A prospective observation study of 301 consecutive CKD patients undergoing coronary angiography was performed.

METHODS

Samples for plasma neutrophil gelatinase-associated lipocalin (NGAL), serum liver fatty acid-binding protein (L-FABP), serum kidney injury marker 1, serum interleukin 18 and serum creatinine were taken at 0, 1, 2, 4, 6 and 48 h post-contrast. Urinary NGAL and urinary cystatin C were collected at 0, 6 and 48 h. Incidence of major adverse clinical events (MACE) was recorded at 1 year. CI-AKI was defined as an absolute delta rise in creatinine of ≥26.5 µmol/l or a 50% relative rise from baseline at 48 h following contrast.

RESULTS

CI-AKI occurred in 28 (9.3%) patients. Plasma NGAL was most predictive of CI-AKI at 6 h. L-FABP performed best at 4 h. A combination of Mehran score > 10, 4 h L-FABP and 6 h NGAL improved specificity to 96.7%. MACE was statistically higher at 1 year in CI-AKI patients (25.0 vs. 6.2% in non-CI-AKI patients).

DISCUSSION/CONCLUSION

Mehran risk score, 4 h serum L-FAPB and 6 h plasma NGAL performed best at early CI-AKI prediction. CI-AKI patients were four times more likely to develop MACE and had a trebling of mortality risk at 1 year.

Evaluation of the protective effect of N-acetylcysteine on contrast media nephropathy

INTRODUCTION

Intravenous contrast agents can cause acute decline in kidney function, especially in patients with risk factors.

OBJECTIVES

In this study, we aimed to examine the ameliorative effect N-acetylcysteine (NAC) to reduce the incidence of contrast nephropathy.

PATIENTS AND METHODS

This study was a prospective, randomized, double-blind clinical trial on 150 patients who underwent coronary angiography. The study was carried out on patients undergoing coronary angiography. Patients were randomly assigned into 2 groups of intervention group and control subjects. Intervention group took NAC 600 mg orally twice a day. It was administered one day before angiography and continued until the second day after angiography. Control subjects received saline only. Serum creatinine was measured before and three days after coronary angiography.

RESULTS

There was no significant difference between intervention and control groups at baseline (P > 0.05). However, there was a significant decline in creatinine level among NAC patients (P = 0.001). Saline group had significantly higher proportion of nephropathy cases than NAC patients Conclusion: We found that the consumption of NAC is useful for contrast induced nephropathy (CIN) prevention.

Contrast-induced nephropathy in patients with chronic kidney disease and peripheral arterial disease

Background

The risk for contrast-induced nephropathy (CIN) after intra-arterial application of an iodine-based contrast material is unknown for patients with chronic kidney disease (CKD) and peripheral arterial disease (PAD).

Purpose

To investigate the incidence of CIN in patients with CKD and PAD.

Material and Methods

This retrospective study was approved by the local ethics committee. One hundred and twenty patients with 128 procedures (73 with baseline eGFR in the range of 45–60 mL/min/1.73m², 55 with eGFR < 45 mL/min/1.73m²) were evaluated. All patients received intra-arterially an iodine-based low-osmolar contrast material (CM) after adequate intravenous hydration with isotonic NaCl 0.9% solution. CIN was defined as an increase in serum creatinine of more than 44 μmol/L within 4 days. The influence of patient-related risk factors (age, weight, body mass index, eGFR, serum creatinine, hypertension, diabetes mellitus, coronary heart disease, heart failure) and therapy-related risk factors (amount of CM, nephrotoxic drugs, number of CM applications) on CIN were examined.

Results

CIN developed in 0% (0/73) of procedures in patients with PAD and an eGFR in the range of 45–60 mL/min/1.73m² and in 10.9% (6/55) of procedures in patients with an eGFR <45 mL/min/1.73m². No risk factor significantly influenced the development of CIN, although baseline serum creatinine (P = 0.06) and baseline eGFR (P = 0.10) showed a considerable dependency.

Conclusion

Patients with an eGFR in the range of 45–60 mL/min/1.73m² and PAD seem not at risk for CIN after intra-arterial CM application and adequate hydration. Whereas, an eGFR < 45 mL/min/1.73m² correlated with a risk of 10.9% for a CIN.

Contrast-induced nephropathy: pathophysiology and preventive strategies

Contrast-induced nephropathy is the third most common cause of hospital-acquired renal failure, after decreased renal perfusion and nephrotoxic medications. Identification of patients at risk and implementation of preventive strategies can decrease the incidence of this nephropathy. Prevention strategies focus on counteracting vasoconstriction, enhancing blood flow through the nephron, and providing protection against injury by oxygen free radicals. Knowledge of the adverse effects associated with infusion of contrast media, identification of patients at risk for contrast-induced nephropathy, and application of evidence-based prevention strategies allow nurses to assist in the prevention of contrast-induced nephropathy.

Comparing the Renal Safety of Isoosmolar Versus Low-Osmolar Contrast Medium by Renal Biomarkers N-Acetyl-β-d-Glucosaminidase and Endothelin

Iodixanol and iopamidol are commonly used contrast agents in coronary angiography. We evaluated the nephrotoxic effects of both contrast media in relation to renal biomarkers. A total of 38 low-risk patients who underwent coronary angiography were enrolled. Patients were randomized to receive either low-osmolar nonionic monomer or isoosmolar nonionic dimer contrast medium. N-Acetyl-β-d-glucosaminidase (NAG), endothelin, blood urea nitrogen, and urine and serum creatinine (SCr) levels were measured before  the procedure (T0), at 6 hours (T6), and at 1 year after the procedure. Plasma endothelin, urine NAG/creatinine, and SCr were higher; accordingly, the urine creatinine values were lower in both the groups when comparing T0 versus T6. The groups were similar with each other when comparing T0 and T6 values. Both the contrast agents may be safely used at a low volume for coronary angiography in low-risk patients. Endothelin and NAG are sensitive to acute renal changes in function. There is a need for further prospective investigations with more patients.

The usefulness of rapid point-of-care creatinine testing for the prevention of contrast-induced nephropathy in the emergency department

BACKGROUND

Renal dysfunction is the most important factor to consider when predicting a patient's risk of developing contrast-induced nephropathy (CIN). Measurement of creatinine (Cr) via rapid point-of-care blood urea nitrogen/creatinine testing (POCT-BUN/Cr) to determine CIN risk could potentially reduce the time required to achieve an accurate diagnosis and to initiate and complete treatment in the emergency department (ED). The aim of our study was to compare the results of POCT-BUN/Cr and reference laboratory tests for BUN and serum Cr.

MATERIALS AND METHODS

A retrospective analysis of suspected stroke patients who presented between November 2009 and November 2010, and had BUN and Cr levels measured by POCT-BUN/Cr, and the reference laboratory tests performed with the blood sample which was transferred to the central laboratory by an air-shoot system. Two assays were conducted on the whole blood (POCT) and serum (reference) by trained technicians. The time interval from arrival at the ED to reporting of the results was assessed for both assays via a computerised physician order entry system.

RESULTS

The mean standard deviation (SD) interval from arrival at the ED to reporting of the results was 11.4 (4.9) min for POCT-BUN/Cr and 46.8 (38.5) min for the serum reference laboratory tests (p<0.001). Intra-class correlation coefficient (ICC) analysis demonstrated a high level of agreement (the consistency agreement) between POCT and the serum reference tests for both BUN (ICC=0.914) and Cr (ICC=0.980).

CONCLUSIONS

This study suggests that POCT-BUN/Cr results correlate well with those of serum reference tests in terms of BUN and Cr levels and, in turn, predicting CIN. POCT-BUN/Cr is easily performed with a rapid turnaround time, suggesting its use in the ED may have substantial clinical benefit.