Letter by Wetzels Regarding Article, “Renal Insufficiency Following Contrast Media Administration Trial (REMEDIAL): A Randomized Comparison of 3 Preventive Strategies”
To the Editor:
In a recent issue of Circulation, results of the REMEDIAL trial were presented.1 The authors concluded that sodium bicarbonate was superior to normal saline for the prevention of contrast agent–induced nephrotoxicity. These data are very interesting and may change current practice. Several questions arise upon critical review of the article.
First, the study was double-blinded, and the authors do not provide detailed information. Were patients who were randomized to sodium bicarbonate sham-infused in the period before contrast injection? How were differences in the infusion rates between the study groups handled?
Second, if we make calculations with the advised hydration schedules for an average 75-kg patient, the typical saline regimen should have consisted of 1800 mL of saline, and the sodium bicarbonate schedule should have been 675 mL of sodium bicarbonate, which is a difference of 1125 mL. The total volumes are reported as 1562 and 1081 mL, respectively, a difference of 481 mL. The authors should provide an explanation; did patients randomized to sodium bicarbonate receive additional saline?
Third, Table 2 of the article indicates that there were no significant differences in 24-hour urine volume. This again suggests that supplementary hydration was used in the sodium bicarbonate group. Fluid retention in the saline group may be an alternative explanation. Are there data on differences in changes in body weight throughout the study?
We feel that more detailed information is needed to fully appreciate the findings of the REMEDIAL trial. In view of the similarities in urine output, it is unclear whether similar results will be obtained if patients are treated with sodium bicarbonate immediately before a contrast procedure without prior hydration.
Briguori C, Airoldi F, D’Andrea D, Bonizzoni E, Morici N, Focaccio A, Michev I, Montorfano M, Carlino M, Cosgrave J, Ricciardelli B, Colombo A. Renal insufficiency following contrast media administration trial (REMEDIAL): a randomized comparison of 3 preventive strategies. Circulation. 2007; 115: 1211–1217.