Imaging
In a single-center study, continuous venovenous hemofiltration before and after radiocontrast exposure reduced AKI; however, the study was flawed by the use of serum creatinine changes as part of the definition of the primary endpoint.62
As GBCAs, radiocontrast is excreted primarily by the kidneys and hemodialysis can effectively remove the agent from the serum. Thus, pharmacokinetics implies that hemodialysis may be a valuable measure to reduce RCIN. However, several studies and meta-analyses suggest there is no benefit from this modality; some even suggest it can do harm.61
Thus, there is no role for renal replacement therapy as a prophylactic therapy.
Finally, potential nephrotoxic drugs should be held prior to and after radiocontrast exposure to limit the development of AKI. Medications such as NSAIDs, aminoglycosides, diuretics (unless fluid overload), and other nephrotoxins should be avoided. Data on the benefits of withholding angiotensin-converting enzyme inhibitors and angiotensin receptor blockers prior to radiocontrast exposure are unclear; however, we recommend discontinuing these drugs until after the procedure, when kidney function is stable. Table 3 summarizes some recommendations to reduce contrast complications.
Alternative Imaging Modalities
The technological advances in the field of radiology are quite impressive. As the field evolves, more accurate, faster, and safer imaging tools are entering clinical practice at a rapid pace. We must therefore investigate these newer tools in patients with underlying kidney disease with an eye on improving safety, while also enhancing imaging accuracy. In particular, we must prioritize the development of alternative non-contrast imaging modalities in this current era of contrast complications (NSF and RCIN).
Ultrasonography should be considered first because it is widely available and the safest imaging modality. Grayscale ultrasound technology provides information about organ size and echogenicity, while Doppler ultrasound can effectively investigate blood flow in veins and arteries. Obesity is a limiting factor, and operator skill and expertise are particularly important for detecting renal artery stenosis. Microbubble contrast agents for ultrasound are useful for enhancing certain structures, especially focal liver lesions and endocardial borders.63
However, limited approval from the FDA due to rare cases of cardiovascular instability has stifled the broader use of these agents.64
1. Grobner T, Gadolinium—a specific trigger for the development of nephrogenic fibrosing dermopathy and nephrogenic systemic fibrosis?, Nephrol Dial Transplant, 2006;21:1104–8.
2. Grainger RG, Thomsen HS, Morcos SK, et al., Intravascular contrast media for radiology, CT and MRI. In: Grainger RG, Allison DJ, Diagnostic Radiology: A Textbook of Medical Imaging, 5th ed, Philadelphia: Elsevier Churchill Livingstone, 2008:31–53.
3. Sherry AD, Caravan P, Lenkinski RE, Primer on gadolinium chemistry, J Magn Reson Imaging, 2009;30:1240–8.
4. Perazella MA, How should nephrologists approach gadolinium- based contrast imaging in patients with kidney disease?, Clin J Am Soc Nephrol, 2008;3:649–51.
5. Aime S, Caravan P, Biodistribution of gadolinium-based contrast agents, including gadolinium deposition, J Magn Reson Imaging, 2009;30:1259–67.
6. Perazella MA, Rodby RA, Gadolinium use in patients with kidney disease: a cause for concern, Semin Dial, 2007;20:179–85.
7. Sieber MA, Lengsfeld P, Frenzel T, et al., Preclinical investigation to compare different gadolinium-based contrast agents regarding their propensity to release gadolinium in vivo
Recent developments have provided new options for non-GBCA MRI. Although not yet approved by the FDA as a contrast agent, ultra-small superparamagnetic iron oxide (ferumoxytol) can be used for brain and vasculature imaging.65
In addition, non-contrast magnetic resonance
angiography (MRA) techniques have been developed as GBCA alternatives. These modalities can image renal vessels and other vascular beds with high precision. Currently, time of flight imaging and arterial spin labeling have been useful for imaging cerebral vasculature, including the Circle of Willis. In addition, phase contrast angiography has been specifically applied for evaluating cerebral venous blood flow. Steady-state free precession and time-space labeling inversion pulse technology can be used for renal artery and peripheral vessel imaging.66 The diffusion-weighted non-enhanced MRI technique can accurately differentiate between different liver pathologies such as cancer, benign cysts, and hemangiomas.67
Blood oxygen level dependent (BOLD) MRI
uses deoxyhemoglobin as an endogenous contrast agent and provides assessment of intrarenal oxygenation.68
It may prove useful as a
non-invasive technique to determine the degree of non-reversible injury in CKD, identify hemodynamic relevant renal artery stenosis, and diagnose chronic allograft dysfunction in transplant recipients.69–71
Finally,
positron emission tomography can quantify renal perfusion non-invasively using radiopharmaceutical agents and has the potential for assessing renal impairment severity and responses to subsequent therapy.72
While
not yet widely available, these modalities may become viable alternatives to GBCA-based MRI/MRA in the near future.
Conclusion
NSF and RCIN are associated with significant consequences, but excessive concern for these outcomes in patients with kidney disease should not cause us to forgo a rational approach to imaging. When weighing the risks and benefits of using contrast-based technologies in the setting of decreased kidney function, one should be mindful of the key principles provided by the available literature. Clinicians must first identify patients at high risk of developing complications. Non-contrast techniques should be the initial consideration in these patients. If no suitable alternative is available, and the risk:benefit ratio falls in favor of using gadolinium-based or radiocontrast agents, then appropriate prophylactic measures should be implemented prior to exposure. Simply accepting underdiagnosis or misdiagnosis of potentially serious diseases in patients with kidney disease is not permissible. n
and to trigger nephrogenic systemic fibrosis-like lesions, Eur Radiol, 2008;18:2164–73.
8. Pietsch H, Lengsfeld P, Steger-Hartmann T, et al., Impact of renal impairment on long-term retention of gadolinium in the rodent skin following the administration of gadolinium-based contrast agents, Invest Radiol, 2009;44:226–33.
9. High WA, Ayers RA, Chandler J, et al., Gadolinium is detectable within the tissue of patients with nephrogenic systemic fibrosis, J Am Acad Dermatol, 2007;56:21–6.
10. White GW, Gibby WA, Tweedle MF, Comparison of Gd(DTPA- BMA) (Omniscan) versus Gd(HP-DO3A) (ProHance) relative to gadolinium retention in human bone tissue by inductively coupled plasma mass spectroscopy, Invest Radiol, 2006;41:272–8.
11. Cowper SE, Robin HS, Steinberg SM, et al., Scleromyxoedema- like cutaneous diseases in renal-dialysis patients, Lancet, 2000;356:1000–1.
12. Cowper SE, Su LD, Bhawan J, et al., Nephrogenic fibrosing dermopathy, Am J Dermatopathol, 2001;23:383–93.
13. Mayr M, Burkhalter F, Bongartz G, Nephrogenic systemic fibrosis: clinical spectrum of disease, J Magn Reson Imaging, 2009;30:1289–97.
14. Cowper SE, Bucala R, Leboit PE, Nephrogenic fibrosing dermopathy/nephrogenic systemic fibrosis—setting the record straight, Semin Arthritis Rheum, 2006;35:208–10.
15. Prince MR, Zhang HL, Prowda JC, et al., Nephrogenic systemic fibrosis and its impact on abdominal imaging, Radiographics, 2009;29:1565–74.
16. Prince MR, Zhang HL, Roditi GH, et al., Risk factors for NSF: a literature review, J Magn Reson Imaging, 2009;30:1298–308.
17. Prince MR, Zhang H, Morris M, et al., Incidence of nephrogenic systemic fibrosis at two large medical centers, Radiology, 2008;248:807–16.
18. Boyd AS, Zic JA, Abraham JL, Gadolinium deposition in nephrogenic fibrosing dermopathy, J Am Acad Dermatol, 2007;56:27–30.
19. Schroeder JA, Weingart C, Coras B, et al., Ultrastructural evidence of dermal gadolinium deposits in a patient with nephrogenic systemic fibrosis and end-stage renal disease, Clin J Am Soc Nephrol, 2008;3:968–75.
20. Evans CH, Drouven BJ, The promotion of collagen polymerization by lanthanide and calcium ions, Biochem J, 1983;213:751–8.
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