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Why ACE inhibitor contraindicated in renal artery stenosis?


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September 10, 2010 12:14AM

In the presence of renal artery stenosis, the resistance in the afferent arteriole is increased. As compensation, Angiotensin II acts to constrict the efferent arteriole in order to achieve adequate profusion of the glomerulus. ACE inhibitors block the conversion of angiotensin I into angiotensin II. Without its vasoconstrictive effect, the efferent arteriole becomes dilated. This leads to a drop in GFR and may lead to renal failure.