Pediatric Renal Artery Stenosis

  • Etiology:
    — In infants – thromboembolism related to umbilical artery catheterization
    — In older children – fibromuscular dysplasia and Takayasu arteritis
  • Imaging US: US of abdominal aorta and depiction of renal size and architecture useful to exclude aortic narrowing, global nephropathy, focal scarring, or tumor
  • US Spectral Doppler: Precise role of Doppler imaging unclear
    — Detect elevated flow velocity across stenotic lumen but no widely accepted pediatric US Doppler diagnostic criteria: renal artery velocity greater than 180 centimeters / second, renal artery to abdominal aorta velocity ratio greater than 3.5:1
    — Depicts tardus and or parvus waveforms in vessels distal to arterial stenosis
    — Localization of accessory renal artery stenosis or branch vessel stenosis is challenging and this is often where stenosis is
  • DDX:
  • Complications: Causes 5-10% of childhood hypertension
  • Treatment: Angioplasty
  • Clinical: Children with drug-resistent hypertension

Radiology Cases of Renal Artery Stenosis

Radiology Cases of Bilateral Renal Artery Stenosis Due to Midaortic Syndrome in Neurofibromatosis Type 1

CT angiogram and spectral doppler US of bilateral renal artery stenosis in a patient with neurofibromatosis Type 1
3D reconstruction of a CT angiogram with contrast of the chest and abdomen (left) shows diffuse moderate narrowing of the mid aorta and marked narrowing of the origins of the renal arteries bilaterally. Spectral doppler US of the renal arteries (right) shows parvus tardis waveforms within them bilaterally.
US and angiogram of bilateral renal artery stenosis due to midaortic syndrome in a patient with Neurofibromatosis Type I
Spectral doppler US of the kidneys (above) shows tardus parvus waveforms in the renal arteries bilaterally. AP image from an abdominal angiogram (below) shows bilateral stenosis of the renal arteries at their origins and progressive narrowing of the mid abdominal aorta centered near the renal artery origins with sparing of the aortic bifurcation.

Radiology Cases of Bilateral Renal Artery Stenosis Due to Midaortic Syndrome

CT of midaortic syndrome and bilateral renal artery stenosis
3D CT angiogram with contrast of the abdomen shows diffuse narrowing of the mid abdominal aorta and marked narrowing of the origins of the bilateral renal arteries.