Which combination is most effective for reducing the risk of contrast-induced nephropathy?

• A. Adequate hydration and using low- or iso-osmolar contrast media.
• B. Prophylactic diuretics only.
• C. Prehydration with high-osmolar contrast media.
• D. No specific preventive measures are recommended.

Answer: (A)

The main idea is that protecting the kidneys from contrast hinges on two actions: keeping the kidneys well-perfused and reducing the toxic effects of the contrast itself. Adequate hydration of the patient with isotonic fluids helps maintain intravascular volume, improves renal blood flow, and dilutes the contrast as it passes through the kidneys, all of which reduce tubular injury and medullary hypoxia. At the same time, using low- or iso-osmolar contrast media lowers the osmotic and direct tubular toxicity compared with high-osmolar agents, further reducing the risk of injury. Together, these strategies provide the strongest protection against contrast-induced nephropathy. Prophylactic diuretics can worsen dehydration and do not reliably prevent CIN. Prehydration with high-osmolar contrast would increase risk rather than decrease it. No preventive measures would miss the opportunity to reduce risk.