N-acetylcysteine (NAC), sodium bicarbonate no help in preventing contrast nephropathy
N-acetylcysteine (NAC) and sodium bicarbonate are commonly provided to patients undergoing angiographic procedures with intravenous contrast. Small randomized trials had suggested NAC or bicarbonate or both could prevent kidney injury from so-called contrast nephropathy.
That practice has no benefit, based on results of a large randomized trial showing neither NAC nor bicarb improved outcomes after contrast angiography.
No matter which pre-treatment the 5,177 patients received -- sodium bicarbonate infusion, 0.9% sodium chloride infusion, five days oral NAC, or placebo -- all arms had the same rates of adverse outcomes. About 4.5% in each group experienced death, renal replacement therapy, persistent kidney injury at 90 days. The trial was stopped early for futility. Results were reported at the American Heart Association meeting and also in the New England Journal of Medicine.
With a large proportion of older patients with diabetes, severe chronic kidney disease (GFR 15-45 mL/min), and a high rate of recurrent hospitalizations, mostly in the U.S., PRESERVE’s findings appear applicable to real-world practice in the United States. The participants were mostly men.
Urinary alkalinization (via bicarbonate) and scavenging of reactive oxygen species (via NAC) are believed by many physicians to prevent injury to renal tubular epithelial cells resulting from iodinated contrast. Despite the appealing theoretical basis, PRESERVE effectively proves any such effects of bicarbonate or NAC are not clinically meaningful.