“Twenty-four hour sodium chloride 0.9% 1ml/kg/h is the regimen of choice whenever maximal protection is desired and logistics permits as it was superior to 7-hour sodium bicarbonate,” Dr. Christian Mueller from University Hospital Basel, Switzerland, noted in an email to Reuters Health.
The study also found that a short-term sodium bicarbonate regimen (20 minutes IV plus once orally) had similar efficacy as 7-hour sodium bicarbonate. This novel regimen “seems to be an attractive alternative for all other patients, including those undergoing outpatient procedures,” Dr. Mueller said.
Twenty-four volume supplementation with sodium chloride 0.9% is “uniformly accepted” and used in clinical practice for prevention of CIN, the study team notes in a report online January 19 in the European Heart Journal.
Despite this, however, the best way to prevent CIN remains uncertain. Some recent studies have hinted that volume supplementation with sodium bicarbonate may work better. (See Reuters Health report Apr. 7, 2011; Sodium bicarbonate helps prevent contrast-induced nephropathy and Oct. 13, 2009: Bicarbonate use cuts risk of contrast nephropathy during PCI).
In a randomized, open-label, controlled three-center study, Dr. Mueller’s team compared three intravenous volume supplementation regimens for CIN prevention: sodium chloride 0.9% 1 mL/kg/h for at least 12 hours before and after the procedure; sodium bicarbonate (166 mEq/L) 3 mL/kg for 1 hour before and 1 mL/kg/h for 6 hour after the procedure; sodium bicarbonate (166 mEq/L) 3 mL/kg over 20 minutes before the procedure plus sodium bicarbonate orally (500 mg per 10 kg).
Participants included 258 consecutive patients with renal insufficiency, defined as acute serum creatinine level above the upper limit of normal or estimated glomerular filtration rate (eGFR) less than 60 mL/min/1.73 m².
Exclusion criteria were age younger than 18 years, pre-existing dialysis, allergy to radiographic contrast, pregnancy, severe heart failure (NYHA functional class III and IV), N-acetylcysteine within 24 hours before contrast, and clinical condition requiring continuous fluid therapy.
All three regimens were safe and well tolerated, even in patients with New York Heart Association (NYHA) class I or II heart failure. “In some patients with heart failure it may be necessary to reduce the infusion rate,” Dr. Mueller said.
The 24-hour sodium chloride regimen was superior to the 7-hour sodium bicarbonate regimen. The maximum change in eGFR within 48 hours (the primary endpoint) was significantly greater with the 7-hour sodium bicarbonate regimen compared with the 24-hour sodium chloride regimen; the mean difference was -3.9 mL/min/1.73 m²; p=0.009).
The short-term sodium bicarbonate regimen was on par with the 7-hour regimen for the primary end point; the maximum change in eGFR within 48 hours was similar in these two groups. The mean difference was 1.3 mL/min/1.73 m²; p=0.39.
The incidence of CIN was significantly lower in the 24-hour sodium chloride arm than in the 7-hour sodium bicarbonate arm (1% vs 9%; p=0.002) and similar in the 7-hour sodium bicarbonate and short-term sodium bicarbonate arm (10%; p=0.9).
The fact that the incidence of CIN was “quite low” overall, attests to the effectiveness of volume supplementation for CIN prevention, the researchers say. “Our data provide a clear and simple message to clinicians: CIN can effectively and safely (be) prevented using volume supplementation,” Dr. Mueller told Reuters Health.
The researchers think their findings have “major clinical implications and will help to
individualize treatment decisions in the prevention of CIN.”
“If maximal protection is required and it is feasible to initiate the infusion 12 h before contrast, a 24 h sodium chloride 0.9% regimen should be used,” they advise. “In all other patients, short-term sodium bicarbonate may be the regimen of choice as it is very easy to apply, even to outpatient procedures, and seems to have similar efficacy to the 7 h sodium bicarbonate regimen.”
The multicenter design of the study and a population representing real-life hospitalized patients with renal insufficiency undergoing a contrast procedure are two strengths of the study. The fact the regimens were compared without the interference of N-acetylcysteine, a known confounder of eGFR, is a third strength.
The fact that the study was not powered to evaluate the impact of the regimens on hard clinical outcomes such as renal replacement therapy and re-admission are two limitations to the study. The study also did not include patients with NYHA class III or IV, so no conclusions can be drawn on the most effective preventive regimen in these patients.
Euro Heart J. 2012. Published online January 19, 2012.