Sodium Bicarbonate Versus Saline for the Prevention of Contrast-Induced Nephropathy - Sodium Bicarbonate Versus Saline for the Prevention of Contrast-Induced Nephropathy
Prior studies seem to indicate that sodium bicarbonate infusion is beneficial in the reduction of contrast-induced nephropathy (CIN), compared with isotonic saline, in patients with chronic kidney disease (CKD) undergoing coronary angiography or intervention. The current study aimed to study a larger population of patients with CKD for a longer duration of time, to determine if there was a true difference between sodium bicarbonate and isotonic saline in the prevention of CIN in patients with CKD.
There will be no difference between sodium bicarbonate and isotonic saline in the prevention of CIN in patients with CKD.
Patients Screened: 1,226
Patients Enrolled: 502
NYHA Class: III/IV: 7.5%
Mean Follow Up: 10 days (30 days for patients with CIN)
Mean Patient Age: 74 years
Mean Ejection Fraction: 47%
- Preangiographic estimated creatinine clearance ≤60 ml/min
- Planned angiography or percutaneous coronary intervention
- Administration of contrast medium within the past 10 days
- End-stage renal disease
Development of CIN, defined as an absolute increase of at least 0.5 mg/dl over baseline serum creatinine within 5 days after the administration of the contrast medium
- Development of CIN, defined as a relative increase of ≥25% over baseline serum creatinine within 5 days after contrast agent administration
- Adverse clinical events, including in-hospital death, acute pulmonary edema, need for dialysis, or hemofiltration
Patients assigned to isotonic saline received 1 ml/kg/h 0.9% sodium chloride for 12 hours before and after the procedure. Patients in the sodium bicarbonate group (154 mEq/L in dextrose and water) received 3 ml/kg for 1 hour before contrast injection, followed by an infusion of 1 ml/kg/h for 6 hours after the procedure. Hydration rate was reduced to 0.5 ml/kg/h in both arms for patients with ejection fraction <40% or New York Heart Association functional class III-IV.
Medications included 600 mg of N-acetylcysteine (NAC) twice daily from the day before to the day after the procedure. All patients received iodixanol, a nonionic iso-osmolar contrast medium.
A total of 502 patients were randomized, 252 to the isotonic saline group, and 250 to the sodium bicarbonate group. The baseline characteristics were fairly well matched between the two groups. The mean baseline creatinine was 1.21 mg/dl, with a mean basal creatinine clearance of 37.5 ml/min; about 15% of patients had an estimated creatinine clearance <30 ml/min. About 39% of patients were on angiotensin-converting enzyme inhibitors, and 31.5% were on diuretics. The mean contrast medium administered was about 175 ml (range 120-230 ml); about 67.5% of patients received at least 140 ml of dye.
In both groups, the baseline creatinine rose significantly from baseline, but the mean absolute increase was not different between the patients who received isotonic saline or sodium bicarbonate (0.14 mg/dl vs. 0.15 mg/dl, p = 0.78). There was no difference in serum creatinine between the two groups at day 1, 2, 3, or 5, or in the peak creatinine postprocedure (1.34 mg/dl vs. 1.37 mg/dl, p = 0.59). The primary endpoint of CIN occurred in 11.5% in the saline group compared with 10% in the sodium bicarbonate group (p = 0.6); this was true when the analysis was restricted to the first 48 hours only (15.1% vs. 10%, p = 0.09). In patients who did develop CIN, there was no difference between the two groups in terms of the serum creatinine at all time points studied, including days 1, 2, 3, 5, 10, and 30 postangiography.
Patients with high risk factors including diabetes, and estimated creatinine clearance <30 ml/min, were more likely to develop CIN in both groups. There was no difference between the two groups in the incidence of death (1.2% vs. 1.6%, p = 0.99), and six of the seven patients who died developed CIN, suggesting a high mortality rate in patients who develop CIN.
The results of this large randomized trial of patients with CKD who are at high risk for developing CIN demonstrate that there is no difference between sodium bicarbonate and isotonic saline in the prevention of CIN. The results of this trial are contrary to prior published trials on this topic, which have demonstrated a significant benefit with sodium bicarbonate infusion in patients with CKD undergoing coronary angiography and/or intervention. The incidence of CIN in patients receiving sodium bicarbonate infusion in these trials was around 1.8-2%, as compared to the current trial, where the incidence of CIN in these patients was 10%.
Although the current trial did follow-up patients for a longer duration compared with the other trials, when CIN incidence at 48 hours was studied, it was still about 10% with sodium bicarbonate infusion. One possible explanation for the difference is the high amount of contrast medium used in this study (mean = 175 ml; 67.5% with ≥140 ml of dye) compared with the other studies, which used about 130 ml of dye on average. In addition to the use of prophylactic agents, such as NAC and hydration, one of the cornerstones for CIN prevention remains the minimization of the amount of dye used.
Another limitation of the current study is that data relating to the effects of bicarbonate on urine and blood pH were not available.
Further studies are needed to clarify the role of sodium bicarbonate infusion versus isotonic saline in the prevention of CIN in patients with CKD undergoing coronary angiography or intervention. The results of the current trial indicate that when large dye loads are anticipated, there may be no difference between the two treatment strategies in the prevention of CIN.
Maioli M, Toso A, Leoncini M, et al. Sodium bicarbonate versus saline for the prevention of contrast-induced nephropathy in patients with renal dysfunction undergoing coronary angiography or intervention. J Am Coll Cardiol 2008;52:599-604.
Keywords: Follow-Up Studies, Water, Diuretics, Risk Factors, Sodium Bicarbonate, Creatinine, Percutaneous Coronary Intervention, Glucose, Contrast Media, Sodium Chloride, Kidney Diseases, Bicarbonates, Coronary Angiography, Diabetes Mellitus, Renal Insufficiency, Chronic
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