Renal Artert Stenosis Flashcards
Define Renal Artery Stenosis?
Stenosis of the renal artery
What is the aetiology of Renal Artery Stenosis?
Atherosclerosis (older patients) FIbromuscular Dysplasia (younger patients)
What is Atherosclerosis in relation to Renal Artery Stenosis?
Widespread aortic disease involving the renal artery ostia
What is the aetiology of Fibromuscular Dysplasia in relation to Renal Artery Stenosis?
May be associated with collagen disorders, neurofibromatosis and Takayasu’s arteritis
May be associated with micro-aneurysms in the mid and distal renal arteries (resembling a string of beads on angiography)
What is the Pathophysiology of Renal Artery Stenosis?
Renal hypoperfusion (due to the stenosis) stimulates the renin-angiotensin system leading to increased angiotensin II and increased aldosterone
This leads to increased BP
The high BP leads to fibrosis, glomerulosclerosis and renal failure
What is the epidemiology of Renal Artery Stenosis?
Prevalence of unknown
Accounts for 1-5% of all hypertension
Fibromuscular dysplasia occurs mainly in women with hypertension < 45 yrs
What are the presenting symptoms of Renal Artery Stenosis?
History of hypertension in < 50 yrs
Hypertension refractory to treatment
Accelerated hypertension and renal deterioration on starting ACE inhibitors
History of flash pulmonary oedema
ACE INHIBITORS ARE BAD IN RENAL ARTERY STENOSIS
What are the signs of Renal Artery Stenosis?
Hypertension
Signs of renal failure in advanced bilateral disease
Renal Artery Bruits
What investigations do we do for Renal Artery Stenosis?
Non-invasive
CT angiogram or MR angiography
Digital Subtraction Angiography
Renal Scintigraphy
What are the Non-Invasive investigations for Renal Artery Stenosis?
Duplex US
US measurement of kidney size
Why do we do CT angiography or MR angiography for Renal Artery Stenosis?
Risk of contrast nephrotoxicity
What is the GOLD STANDARD Investigation for Renal Artery Stenosis?
Digital Subtraction Angiography
What is Renal Scintigraphy for Renal Artery Stenosis?
Uses radio-agent that is either excreted by glomerular filtration or by the tubules
Addition of an ACE inhibitor causes delayed clearance by the affected kidney (may not be useful in bilateral renal artery stenosis)
