The narrowing of one or both renal arteries, which reduces blood flow to the kidneys and can lead to ↑High BP and kidney dysfunction.

• primarily large vessel disease, vsHypertensive nephropathy (affect small vessels too)

Management

ARB (-sartan) ( NOT ACEi, Bilateral RAS = Contra-indication to ACEi)

• Angiotensin II act on the efferent arteriole to maintain filtration pressure when BP is low.
• In this case, both kidneys have severely reduced blood flow. The kidneys are highly dependent on angiotensin II to maintain filtration pressure.
  • ACEi removes that compensation → dramatic fall in GFR → AKI.
  • However, ARB still allows Angiotensin II to be made, so ARB can be used