The Canadian Association of Radiologists Guidelines for the Prevention of Contrast-induced Nephropathy: A Critical Appraisal

Objective

The purpose of this study is to critically appraise the Canadian Association of Radiologists (CAR) guidelines on the prevention of contrast-induced nephropathy (CIN).

Methods

The Appraisal of Guidelines Research and Evaluation (AGREE) tool is a questionnaire that consists of 23 key items organized in 6 domains (scope and purpose, stakeholder involvement, rigor of development, clarity and presentation, applicability, editorial independence). Four radiologists read the guidelines and completed the questionnaire independently. To assess the quality of the evidence, the articles listed in the bibliography were reviewed, and the following data were collected and tabulated: the type of contrast, the administration route, and the level of evidence (Centre for Evidence Based Medicine, University of Oxford).

Results

The highest score was for scope and purpose (92%), whereas the lowest scores were for rigor of development (50%) and applicability (40%). The score for the remaining domains were the following: stakeholder involvement (59%), clarity and presentation (69%), and editorial independence (63%). Although the bibliography of the CAR guidelines list 46 articles, only 33 were deemed pertinent to support the recommendations related to risk stratification or risk reduction of CIN. Only 3 articles dealt specifically with intravenous injection of iodinated contrast. Four articles dealt with ionic contrast, and, in 17 references, the contrast type was not specified. The best evidence (level 1) was in support of risk-reduction recommendations, but, in 8 of the 9 articles cited, the route of administration studied was exclusively intra-arterial.

Conclusion

It would be appropriate to revisit the topic of CIN and formulate new guidelines. A formal systematic review of the literature should be undertaken and the data extraction should specifically address contrast type and route of administration, as well as the applicability of any recommendations.

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.

Incidence of contrast-induced nephropathy in patients with multiple myeloma undergoing contrast-enhanced CT

OBJECTIVE

The purpose of this article is to evaluate the incidence of contrast-induced nephropathy (CIN) and the effects of associated risk factors in patients with multiple myeloma undergoing contrast-enhanced CT (CECT) with IV administration of nonionic iodinated contrast agent.

MATERIALS AND METHODS

This retrospective review of medical records identified patients with a diagnosis of myeloma who underwent a CECT examination of the chest, abdomen, or pelvis between January 1, 2005, and December 1, 2008. Analysis for CIN, as defined by an increase in creatinine level after the CECT examination of 25% or more, or of 0.5 mg/dL, compared with the level before the CECT examination, both within 48 hours and within 7 days, was performed. Statistical correlations between the development of CIN and creatinine level before CECT examination, patient location, type and amount of contrast agent, blood urea nitrogen-creatinine ratio, history of diabetes, hypercalcemia, Bence Jones proteinuria, β(2)-microglobulin level, albumin level, International Myeloma Staging System stage, and history of myeloma provided at the time the CT examination was ordered were calculated.

RESULTS

Forty-six patients who completed 80 unique examinations were included; their average creatinine level before CECT examination was 0.97 mg/dL. There was no significant difference in the average creatinine levels before CT examination between patients without and those with CIN. Four (5%) and 12 (15%) patients developed CIN within 48 hours and 7 days, respectively. Only serum β(2)-microglobulin level showed a statistically significant (p = 0.03) correlation with the development of CIN.

CONCLUSION

The incidence of CIN in patients with multiple myeloma with a normal creatinine level is low and correlates with β(2)-microglobulin levels. The administration of contrast agent in this patient population is safe but should be based on the potential benefit of the examination and the expected low risk of developing CIN.

Contrast medium-induced acute kidney injury: comparison of intravenous and intraarterial administration of iodinated contrast medium

PURPOSE

To compare the incidence of contrast medium-induced acute kidney injury (AKI) after intravenous (IV) administration of iodixanol for computed tomographic (CT) angiography versus intraarterial (IA) injection of iodixanol or low osmolar contrast medium (LOCM) for digital subtraction angiography (DSA) within the same population suspected of peripheral arterial occlusive disease (PAOD).

MATERIALS AND METHODS

CT angiography was performed with IV iodixanol 320 mgI/mL. After a washout period of 3-14 days, DSA was performed with IA iodixanol or LOCM. Serum creatinine was measured at baseline and 24 hours after administration. Contrast medium-induced AKI was defined by a serum creatinine increase of at least 25% versus baseline at 24 hours. Data were analyzed with χ(2) statistics.

RESULTS

Mean baseline serum creatinine values were comparable between CT angiography with IV contrast medium and DSA with IA contrast medium (93.3 μmol/L ± 52.92 vs 92.8 μmol/L ± 61.70). The incidence of AKI for CT angiography after IV iodixanol administration was 7.6% (20 of 264), which was not statistically different than the 8.7% incidence (22 of 253) for DSA with IA iodixanol or LOCM (P = .641). In the 143 patients who received only iodixanol for both procedures, incidences of contrast medium-induced AKI were comparable after IV (7.0%) and IA (5.6%) administration (P = .626).

CONCLUSIONS

The rates of contrast medium-induced AKI are not statistically different between IV iodixanol for CT angiography and IA iodixanol or another LOCM for DSA in the same population with suspected PAOD.

Creatinine increases after intravenous contrast administration: incidence and impact

OBJECTIVE

The incidence of creatinine increases after intravenous contrast (postcontrast creatinine increases, PCCI) is controversial, ranging from 0% to >25%. We sought to determine what factors influenced these divergent estimates of PCCI incidence. Where possible, the association of PCCI with long-term adverse outcomes was also studied.

MATERIALS AND METHODS

Both observational studies and prospective randomized trials were reviewed. Definitions of clinically significant PCCI, incidence of PCCI, and its association with baseline kidney function, the setting in which intravenous contrast was administered, and the short- and long-term consequences of PCCI were extracted.

RESULTS

Baseline renal function impairment and inpatient versus outpatient status are the major risk factors for PCCI. PCCI is possibly associated with clinically significant short- and long-term adverse events.

CONCLUSIONS

PCCI occurs despite a number of potential confounding issues. The incidence is increased as kidney function at baseline is diminished and for inpatients. There is limited data on long-term outcomes following PCCI in this setting.

[Complications due to contrast agent administration: what has been confirmed in prevention?]

Computed tomography (CT) and magnetic resonance imaging (MRI) have been evaluated by internists to be the most important medical innovations. Often, intravenous contrast agent administration is required for answering the clinical questions to CT and MRI. In this review we present an overview of the most common and most important aspects that need to be considered prior to intravenous contrast agent administration. We discuss aspects of renal impairment (contrast-induced nephropathy, nephrogenic systemic fibrosis), allergy-like reactions, hyperthyroidism, and pregnancy and breast-feeding.

Contrast-induced nephropathy after intravenous administration: fact or fiction?

Recent prospective clinical investigations in high-risk patients receiving intravenous contrast media for computed tomography (CT) suggest that the incidence and serious negative clinical outcomes are much less common than previously believed. Additional perspectives comparing random variations in serum creatinine in subjects not receiving contrast media show similar fluctuations that would equate to contrast-induced nephrotoxicity (CIN). Putative mechanisms for how CIN could cause death or other serious adverse clinical consequences have not been elucidated.

Sodium bicarbonate for prevention of contrast-induced acute kidney injury: a systematic review and meta-analysis

BACKGROUND

There have been conflicting reports on the use of intravenous administration of sodium bicarbonate for prevention of contrast-induced acute kidney injury (CI-AKI). The aim of this study was to evaluate the use of sodium bicarbonate for prevention of CI-AKI.

METHODS

This is a symptomatic review and meta-analysis of prospectively randomized studies, abstracts and manuscripts, published from 1950 to 20 February 2009.

RESULTS

Of 192 identified publications, 18 studies (n = 3055) were included. Nine studies were only published as an abstract. CI-AKI occurred in 11.6%. Six prospective studies demonstrated that intervention with sodium bicarbonate resulted in a decreased risk of CI-AKI. The aggregate result of the prospective trials also demonstrated a benefit favouring sodium bicarbonate (RR = 0.66, 95% CI = 0.45-0.95). This effect was most prominent in coronary procedures and in patients with chronic kidney disease. There was no effect on need for renal replacement therapy (RRT) and mortality. Published manuscripts demonstrated a beneficial effect, while abstracts could not. Also, funnel plot analysis suggested a publication bias. In addition, we found significant clinical and statistical heterogeneity between studies. Finally, the quality of the individual studies was limited.

CONCLUSIONS

The incidence of CI-AKI was higher than recently reported, and varied among study cohorts. We found a preventive effect of the use of sodium bicarbonate on the risk for CI-AKI, however, with borderline statistical significance. There was no effect on need for RRT or mortality. The relative low quality of the individual studies, heterogeneity and possible publication bias means that only a limited recommendation can be made in favour of the use of sodium bicarbonate.