A 60-year-old diabetic woman develops angina and will need a coronary angiogram for evaluation of coronary artery disease. She has a creatinine of 2.2. Which of the following is the most effective in reducing the risk of contrast-induced nephropathy?

Contrast agents harm the kidney by causing the production of oxygen radicals and by causing vasoconstriction, both of which can lead to acute kidney injury. Patients with underlying kidney disease at baseline, those with diabetes, congestive heart failure, multiple myeloma, and dehydration are at greatest risk of this complication. Pre-hydration with IV normal saline or bicarbonate has been proven to decrease the risk of contrast nephropathy. V-acetylcysteine is also used by some clinicians for prevention, though studies have not been as convincing as those using saline or bicarbonate. Mannitol, dopamine, and prophylactic hemodialysis have been studied and found ineffective in preventing contrast nephropathy. Indomethacin would cause further vasoconstriction and is contraindicated in patients with renal insufficiency.