Renal Artery Stenosis Flashcards
What is renal artery stenosis?
Narrowing of the renal artery lumen (>50% reduction)
What does renal artery stenosis lead to?
reduced perfusion
What does reduced perfusion lead to?
- Structural adaptations to Chronically insufficient oxygen supply leads to Ischaemic nephropathy
- Activation of renin-angiotensin system leads to Renovascular HTN
What are patho changes that occur in kidney due to underperfusion?
- atrophy of tubular cells
- fibrosis of the capillary tuft
- intra-renal arterial medial thickening.
What does activation of the renin-angiotensin system cause?
increased systemic vascular resistance and sodium retention
What are two key causes of renal artery stenosis?
- Renal artery atheroscelrosis
2. Muscular fibrodysplasia
What is renal artery athersclerosis associated with?
-Atherosclerotic plaque buildup
1. Diabetes mellitus
2. Vascular disease
3. Coronary artery
disease
4. Obesity
5. (fat calcium and immune cells)
How does muscular fibrodysplasia cause renal artery stenosis?
- Abnormal development of arterial wall
- Alternating areas of stenosis and dilation
(string of beads)
What is and example of presentation of renal artery stenosis?
severe, progressive, and/or difficult-to-control hypertension, sometimes causing end-organ damage
What is the presentation of renal artery stenosis due to fibromsuculaer dysplasia?
onset of HTN before the age of 30
What is contraindicated in bilateral renal artery stenosis what can it cause?
- contraindication for ACEi because patients require angiotensin II to maintain adequate glomerular filtration
- Can cause AKI after starting an ACEi or ARB
How else can renal artery stenosis present?
recurring flash pulmonary oedema
What bloods are done in renal artery stenosis?
- U+Es
2. Aldosterone-to-renin ratio
What bedside test is done in renal artery stenosis?
urinalysis
What imaging is done in renal artery stenosis?
- Duplex USS
* MR/CT angiography
