What are the guidelines for using Intravenous (IV) contrast agents in patients with Acute Kidney Injury (AKI)?

From the Guidelines

Intravenous contrast agents should be used cautiously in patients with acute kidney injury (AKI), with careful evaluation of the risks and benefits, and implementation of preventive measures to minimize the risk of contrast-induced nephropathy (CIN). For patients with established AKI, it is generally recommended to delay contrast studies until kidney function improves, if clinically feasible. When contrast administration is deemed necessary despite AKI, several preventive measures should be implemented.

• Adequate hydration is crucial, typically with isotonic saline (0.9% NaCl) at 1-1.5 mL/kg/hour for 6-12 hours before and after contrast exposure, as recommended by 1 and 1.
• The lowest possible dose of contrast should be used, preferably iso-osmolar or low-osmolar contrast agents like iodixanol (Visipaque) or iohexol (Omnipaque), rather than high-osmolar agents, as suggested by 1 and 1.
• Nephrotoxic medications such as NSAIDs, aminoglycosides, and ACE inhibitors should be temporarily discontinued 24-48 hours before contrast administration if possible.
• N-acetylcysteine (600-1200 mg orally twice daily, day before and day of procedure) is not recommended for routine use in preventing contrast-induced AKI, as its efficacy is uncertain and it may not provide significant benefit, as indicated by 1 and 1.
• Serum creatinine should be monitored 24-72 hours after contrast exposure to assess for worsening kidney function. These precautions are important because contrast agents can cause renal vasoconstriction and direct tubular toxicity, potentially exacerbating existing kidney injury. The most recent and highest quality study, 1, suggests that the benefits of N-acetylcysteine in preventing contrast-induced AKI are uncertain and may not be significant, and therefore, it should not be used as a routine preventive measure.

From the FDA Drug Label

Contrast-Induced Acute Kidney Injury Advise the patient concerning appropriate hydration to decrease the risk of contrast-induced acute kidney injury [see Warnings and Precautions (5.3)].

The guidelines for using Intravenous (IV) contrast agents in patients with Acute Kidney Injury (AKI) include advising the patient on appropriate hydration to decrease the risk of contrast-induced acute kidney injury 2.

• Key points:
  • Hydration is crucial to reduce the risk of contrast-induced AKI.
  • Patients should be advised to report any signs or symptoms of hypersensitivity reactions during the procedure and to seek immediate medical attention for any signs or symptoms experienced after discharge.
• Main consideration: The use of IV contrast agents in patients with AKI requires careful consideration of the potential risks and benefits, and patients should be closely monitored for signs of contrast-induced nephropathy 2.

From the Research

Guidelines for Using IV Contrast Agents in Patients with AKI

The use of intravenous (IV) contrast agents in patients with acute kidney injury (AKI) requires careful consideration of the potential risks and benefits. Several studies have investigated the guidelines for using IV contrast agents in these patients.

• Risk Factors: Patients with preexisting chronic kidney disease, diabetes mellitus, old age, high volume of contrast agent, congestive heart failure, hypotension, anemia, use of nephrotoxic drug, and volume depletion are at increased risk of developing contrast-induced AKI (CI-AKI) 3, 4, 5.
• Prevention Strategies: Intravascular volume expansion with either isotonic saline or sodium bicarbonate solutions has been shown to be effective in preventing CI-AKI 3, 4, 6. The use of low-osmolar contrast agents and limiting the contrast volume to the minimum necessary are also recommended 4, 7.
• Maximum Allowable Contrast Dose (MACD): The MACD is an important modifiable risk factor for CI-AKI, and several studies have demonstrated that exceeding the MACD is associated with a higher incidence of CI-AKI 7.
• Other Measures: Other measures that may help prevent CI-AKI include the adoption of the transradial approach, the use of automated contrast injectors and small catheters to limit contrast volume, and the use of staged procedures 7.

Recommendations

Based on the available evidence, the following recommendations can be made:

• Identify high-risk patients and consider alternative imaging procedures that do not involve the administration of iodinated contrast 4, 5.
• Use intravascular volume expansion with either isotonic saline or sodium bicarbonate solutions to prevent CI-AKI 3, 4, 6.
• Limit the contrast volume to the minimum necessary and use low-osmolar contrast agents 4, 7.
• Calculate the MACD and contrast volume to eGFR ratio prior to a planned cardiovascular procedure to minimize contrast volume and prevent CI-AKI 7.