Which class of antihypertensive agents is contraindicated in patients with bilateral renal artery stenosis?

Angiotensin-converting enzyme (ACE) inhibitors are contraindicated in patients with bilateral renal artery stenosis due to the risk of acute renal failure. In individuals with this condition, the stenosis leads to a decreased renal blood flow on both sides. ACE inhibitors work by inhibiting the conversion of angiotensin I to angiotensin II, a peptide that constricts blood vessels and increases blood pressure. When ACE inhibitors are administered, they can cause dilation of the efferent arterioles in the kidneys, reducing glomerular filtration pressure. In patients with already compromised renal perfusion from bilateral renal artery stenosis, this further decreased pressure can result in acute kidney injury, as their kidneys are highly dependent on angiotensin II for maintaining glomerular filtration.

Other classes of antihypertensive agents, such as calcium channel blockers, thiazide diuretics, and potassium-sparing diuretics, do not have the same effect on renal blood flow and are typically considered safer alternatives for managing hypertension in patients with renal artery disease, making them more appropriate options for these patients. It's essential for clinicians to be aware of these contraindications to avoid severe complications in susceptible populations.