CORRESPONDENCE: LETTER TO THE EDITOR
Reply
Po-Tseng Lee, MD,
Kang-Ju Chou, MD and
Hua-Chang Fang, MD*
* Division of Nephrology, Kaohsiung Veterans General Hospital, 386 Ta-Chung 1st Road, Kaohsiung, Taiwan 813 (Email: hcfang{at}isca.vghks.gov.tw).
Many previous studies have shown renal failure is the main risk factor predicting development of contrast nephropathy. Renal failure impairs excretion of contrast medium, prolongs exposure to contrast medium, and enhances its damage. According to the pharmacokinetic characteristics of contrast medium, it can be efficiently removed from plasma by hemodialysis, even better than by a normal kidney (1). Theoretically, reduction of exposure of contrast medium by hemodialysis should prevent contrast nephropathy. Although detailed comparison between our experiment and previous studies had not been mentioned in our report (2), I would like to re-emphasize the key factor resulting in a beneficial impact of preventive dialysis in contrast nephropathy is selection of high-risk patients. Most previous studies with a negative result either included a small number of patients or were not properly randomized (3,4).
It is generally accepted that renal replacement therapy should be started when glomerular filtration rate is <15 ml/min with uremic symptoms or evidence of malnutrition. However, until now, no strict randomized controlled trial has proven that early initiation of dialysis accounts for a better survival. Despite the availability of clinical guidelines for the timing of dialysis initiation, most patients started the treatment at very low levels of glomerular filtration rate. Therefore, in addition to an uneventful post-catheterization course, shorter duration of hospitalization, and lower costs, preventive hemodialysis can prevent early entrance of an unexpected dialysis-dependent condition. According to our preliminary results of post-hospitalization follow-up, the benefit can be maintained for as long as 1 year after contrast exposure, showing a more than 2-fold 1-year cumulative dialysis-free survival (85% vs. 40%, p = 0.001). Furthermore, patients with moderate renal failure might benefit from the strategy as well as those with advanced renal failure. In this patient population, it is more difficult to appreciate its impact in short-term investigation. To justify use of preventive hemodialysis in these patients, future investigation should look into the impact of the strategy applied in diabetes patients with moderate renal failure and focus on the incidence of plasma creatinine level doubling after contrast medium exposure.
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References
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- Morcos SK, Thomsen HS, Webb JA. Contrast Media Safety Committee of the European Society of Urogenital Radiology (ESUR) Eur Radiol 2002;12:3026-3030.[Medline]
- Lee PT, Chou KJ, Liu CP, et al. Renal protection for coronary angiography in advanced renal failure patients by prophylactic hemodialysis. A randomized controlled trial. J Am Coll Cardiol 2007;50:1015-1020.[Abstract/Free Full Text]
- Vogt B, Ferrari P, Schönholzer C, et al. Prophylactic hemodialysis after radiocontrast media in patients with renal insufficiency is potentially harmful Am J Med 2001;111:692-698.[CrossRef][ISI][Medline]
- Frank H, Werner D, Lorusso V, et al. Simultaneous hemodialysis during coronary angiography fails to prevent radiocontrast-induced nephropathy in chronic renal failure Clin Nephrol 2003;60:176-182.[ISI][Medline]
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Prophylactic Use of Hemodialysis to Prevent Radiocontrast-Induced Nephropathy: The Discussion Is Open Again!
- Dominik E. Uehlinger
J. Am. Coll. Cardiol. 2008 51: 1047-1048.
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