CONTRAST NEPHROPATHY

IV radiocontrast agents can induce nephropathy

Thought to be due to a direct toxic effect on tubular epithelial cells

Primary risk factor is pre-existing renal failure

Preventive approaches:

  1. Adequate hydration may reduce risk
  2. Hemofiltration
    1. Hemofiltration (1 liter/h fluid replacement) starting 4-8h before contrast administration and continuing 18-24h after completion of procedure, c/w isotonic saline hydration, was ass'd with sig. lower in-hospital mortality (2% vs. 14%), 1y mortality (10% vs. 30%), sig. lower frequency of (increase of serum Cr > 25% over baseline) (5% vs. 50%) and sig. less frequent need for temporary renal-replacement therapy (hemodialysis of hemofiltration) (3% vs. 25%) in a randomized study of 114 pts with chronic renal failure (serum Cr > 2.0mg/dL) undergoing coronary angiography (NEJM 349:1333, 2003--abst)
  3. Oral N-acetylcysteine
    1. In a randomized trial in 83 pts with serum Cr > 1.2mg/dL or CrCl < 50mL/min underoing elective CT w/IV contrast, N-acetylcysteine 600mg PO BID on the days before and after the procedure, c/w placebo, was ass'd with sig. lower incidence of > 0.4mg/dL increase in serum Cr at 48h (2% vs. 21%); no sig. adverse effects observed (NEJM 343:180, 2000--JW)
    2. In a randomized trial in 200 pts with serum Cr > 1.2mg/dL or CrCl < 60mL/min undergoing elective coronary angiography, randomized to N-acetylcysteine 600mg PO BID vs. placebo on the day before and of the procedure (along with 1cc/kg bwt/hrx12h before Px, hr after Px), N-acetylcysteine was ass'd with sig. reduced incidence of > 25% increase in serum Cr at 48h (4% vs. 12%); mean increase in CrCl at 48h c/w baseline was sig. greater in N-acetylcysteine group.  Mean hospital stay sig. shorter w/acetylcysteine (0.9 vs. 2.0d) (JAMA 289:553, 2003--JW)
    3. In a meta-analysis of 7 RCTs of acetylcysteine vs. placebo for prevention of contrast nephropathy, acetylcysteine was ass'd with RR 0.44 for nephropathy (Lancet 362:598, 2003--AFP)
  4. Fenoldopam (click on link for pharmacologic information)
    1. 315 pts (mean age 70yo, 49% w/DM) with CrCl < 60mL/min underoing coronary angiography randomized to fenoldopam (target dose 0.1ug/kg/min) starting 1h before and continued until 12h after catheterization vs. placebo; about half of both groups received N-acetylcysteine.  No sig. diff. in incidence of increase in serum Cr > 25% from 24-96h after completion of administration or 30d incidence of death, dialysis, MI, or rehospitalization ("CONTRAST" study--JAMA 290:2284, 2003--JW)