Renal Artery stenosis

RENAL ARTERY STENOSIS

Definition

• Narrowing or complete stenosis of renal artery.
• It can affect one or both arteries.

What Happens due to stenosis

• Stenosis of renal artery renal ischemia
• Release of renin, angiotensin and then aldosterone all these substances cause vasoconstriction & raise the BP

ETIOLOGY OF R.A.S.

• 1) ATHEROSCLEROSIS:

  • 85% of RAS cases. More in elderly
  • Patient usually has atherosclerosis in other vessels also ( C.A.D. & PVD)

• 2) FIBROMUSCULAR DYSPLASIA:

  • Thickening of the renal artery wall
  • 10% -15% of cases. (females, young ppl)

WHEN TO SUSPECT

• 1. BP not controlled even with 3 medicines
• 2. Occurrence of “ flash pulmonary edema” w/out any cardiac disease
• 3. Abdominal bruit on auscultation
• 4. Affected kidney is smaller than the other
• 5. HTN in a young person
• 6. Severe worsening of serum creatinine after starting ACE or ARB

IMAGING FOR R.A.S.

• Doppler u/s :
• Initial test * Non-invasive
• 2. MRA/CT: (magnetic resonance angiogram)
• More clear images * done if u/s doppler not clear * MRA is also non-invasive like Doppler
• 3. Angiogram:z
• Gold standard, but invasive
• Not the first step test
• Done if noninvasive tests are inconclusive.

Angiogram showing renal art. stenosis

ANGIOGRAM

“String of beads” appearance of renal artery in fibromuscular dysplasia

TREATMENT OF R.A.S.

1. ***Atherosclerotic RAS: ***

• BP control w/ meds. * No ACEI & ARB
• Treatment to lower the cholesterol ( because it is due to atherosclerosis)
• Usually, no surgery or angioplasty ( done only if severe stenosis)

2. Fibromuscular Dysplasia:

• Dilation of the stenosis by angioplasty wth. or without stent