Coronary Artery Disease USMLE Step 1 Practice Question
A 70-year-old man with a history of myocardial infarction 2 years ago and stage 3b chronic kidney disease (serum creatinine 2.8 mg/dL, eGFR 22 mL/min/1.73m²) presents with 3 months of exertional substernal chest pain. Vital signs are BP 148/82 mmHg, HR 88 bpm, RR 16, SpO₂ 98% on room air. Stress testing demonstrates inducible ischemia in the left anterior descending distribution. Coronary angiography with percutaneous coronary intervention is planned. Current medications include metoprolol, lisinopril, and metformin. Which of the following is the most effective intervention to reduce the risk of contrast-induced acute kidney injury during this procedure?
Answer choices
- AHigh-dose loop diuretics before and after the procedure to maintain urine output >200 mL/hour
- BMannitol infusion during the procedure combined with N-acetylcysteine
- CIsotonic saline hydration perioperatively and discontinuation of metformin for 48 hours after the procedureCorrect answer
- DLow-osmolar contrast medium with acetazolamide to alkalinize urine and prevent tubular obstruction
- ESodium bicarbonate hydration with N-acetylcysteine, and holding ACE inhibitor on the day of procedure
- FHigh-osmolar contrast medium to reduce fluid overload risk in chronic kidney disease
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