Contrast-induced nephropathy prevention strategy

This topic will discuss the prevention of contrast-induced nephropathy.
Abdelwahab Ward, BS Pharm, PharmD

Overview ã…¡ Risk factors for contrast-induced nephropathy include creatinine clearance less than 60 mL/min (stages 3–5 chronic kidney disease), diabetes mellitus (with renal insufficiency), hypertension, chronic heart failure, cirrhosis, nephrosis, age over 75 years, cholesterol emboli syndrome, and multiple myeloma.

Additional risk factors include hypovolemia, intraprocedural volume depletion, use of large volumes of contrast, and intra-aortic balloon pump. Urine albumin/creatinine ratio greater than 30 and proteinuria also contribute to risk. Concurrent use of nephrotoxins, such as aminoglycosides, polymixins, amphotericin B, foscarnet, cyclosporine, tacrolimus, and NSAIDs, as well as other medications like angiotensin-converting enzyme inhibitors, angiotensin receptor blockers, and diuretics, further increases risk. Intra-arterial contrast administration may present a higher risk than the intravenous route.

Prevention strategies

The first preventative strategy is to address any reversible risk factors. Start saline hydration to ensure euvolemia and good urine output. Use if there are no contraindications to volume expansion. Hold diuretics the day before and of the procedure. Isotonic saline preferred over 0.45 % saline, start 2 hr (up to 12 hr in high-risk patients) before procedure (1 mL/kg/hr) and continue for at least 6 hr after the procedure. Target urine output around 150 mL/hr.

  • Sodium bicarbonate found to be more effective than isotonic saline hydration; some clinicians have questioned this trial’s methodology.
    • Sodium bicarbonate 3 amps in 1 L D5W, start by 3 mL/kg/hr for 1 hr before contrast then 1 mL/kg/hr for 6 hr after the procedure.
  • Choice of contrast agent. Use nonionic and either low or iso-osmolar products (e.g., iodixanol 'Visipaque'). Use the least amount of volume to complete the procedure.
    • A total volume that is > 5 mL/kg divided by the patient’s serum creatinine in mg/dL is associated with increased risk of nephropathy.
    • Avoid studies that are closely spaced.
    • Optimal time not well delineated; prudent to wait a few days between studies when possible.

Pharmacotherapy

N-acetylcysteine (NAC) 600 mg enterally every 12 hr (24 hr before and 24 hr after the procedure). For emergent procedures, 1 g of NAC administered 1 h before and 4 hr after the procedure may have some value.

  • Intravenous: 150 mg/kg in 500 mL D5W over 30 min before the procedure, followed by 50 mg/kg in 500 mL D5W over 4 hr following the procedure.

Limited if any value based on the available literature:

  • Forced diuresis with either a loop diuretic or mannitol.
  • Renal dose dopamine.
  • Aminophylline/theophylline (adenosine receptor antagonists).
  • Calcium-channel blockers.
  • Fenoldopam.
  • Hemodialysis or hemofiltration.

References

Abdelwahab Ward, BS Pharm, PharmD