A 68-year-old man with hypertension and type 2 diabetes mellitus undergoes coronary angiography for evaluation of unstable angina. Two days later, he develops decreased urine output and swelling in his legs. Laboratory testing shows a creatinine level of 2.4 mg/dL. Prior to the procedure, creatinine was 1.2 mg/dL. Urinalysis shows muddy brown casts with mild proteinuria. There is no hematuria. The patient’s medications include aspirin, metformin, lisinopril, and atorvastatin. Which of the following preoperative interventions would most likely have prevented this complication?
A. Administration of 0.9% isotonic saline
B. Administration of N-acetylcysteine
C. Discontinuation of the metformin
D. Discontinuation of the salicylate
E. Use of lower contrast dose
