Final answer:
The nurse should be most concerned about renal artery stenosis when a patient with hypertension is prescribed an ACE inhibitor due to the potential risk of acute renal failure.
Step-by-step explanation:
The nurse reviewing a patient with hypertension and prescribed an angiotensin-converting enzyme (ACE) inhibitor will be most concerned about renal artery stenosis. ACE inhibitors are known to lower blood pressure by inhibiting the conversion of angiotensin I to angiotensin II, thereby relaxing blood vessels. However, these medications can have a significant impact on kidney function. Specifically, patients with renal artery stenosis may experience a decrease in renal perfusion pressure, which can lead to acute renal failure when ACE inhibitors are used because these drugs further lower the pressure in the glomerular capillaries.