In CKD, which condition increases the risk of AKI when using ACE inhibitors or ARBs?

• A. Bilateral renal artery stenosis
• B. Unilateral renal artery stenosis
• C. Hypotension
• D. Hypernatremia

Answer: (A)

The main concept is how ACE inhibitors and ARBs affect kidney hemodynamics when renal arteries are narrowed. In kidneys with renal artery stenosis, especially when both kidneys are affected, angiotensin II helps maintain glomerular filtration by constricting the efferent arteriole. Blocking angiotensin II with these drugs removes this compensatory constriction, lowering glomerular pressure and GFR. When both kidneys rely on this mechanism, the drop in filtration pressure can precipitate acute kidney injury. If only one kidney is stenotic, the other kidney can compensate and AKI is less likely. Hypotension or hypernatremia can occur with these drugs, but the strongest risk factor for AKI in this setting is bilateral renal artery stenosis.