Transplant Renal Artery Stenosis

Imaging

• Color, power, spectral Doppler US is screening modality for transplant renal artery stenosis

• Stenosis occurs most commonly at arterial anastomosis but can occur along length of artery

• Focal elevation of peak systolic velocity (PSV) > 250-300 cm/s at stenosis with poststenotic turbulence

• Color aliasing and soft tissue vibration at area of stenosis

• Renal artery to Iliac PSV ratio > 1.8-3.5

• Secondary sign: Tardus parvus intrarenal waveforms = slow systolic upstroke and decreased peak velocity

  • Decreased acceleration index < 3 m/s² and increased acceleration time > 0.1 s in segmental arteries

  • Low resistive index (RI) < 0.5

• Catheter angiography is gold standard for diagnosis and allows treatment with angioplasty or stenting