Abdominal and Visceral Vascular Testing
Abdominal and Visceral Vascular Testing
This domain covers duplex evaluation of the abdominal aorta, renal arteries, mesenteric arteries, and visceral and transplant vasculature.
Core rules
- Perform renal artery duplex fasting. A renal artery PSV ≥180-200 cm/s and renal-aortic ratio ≥3.5 suggest ≥60% stenosis. Measure at the origin and avoid angle >60°; bowel gas and depth often limit the examination.
- For mesenteric ischemia, SMA PSV ≥275 cm/s suggests ≥70% stenosis; celiac PSV ≥200 cm/s suggests stenosis. Median arcuate ligament compression typically produces celiac narrowing that worsens in expiration and improves in inspiration.
- Abdominal aortic aneurysm is an infrarenal diameter ≥3.0 cm. Surveillance intervals depend on size; endoleak after endovascular repair appears as flow outside the stent graft but within the sac.
- Transplant renal artery stenosis may show elevated PSV, tardus-parvus distal waveform, and resistive index changes; interpret with clinical function.
Worked example
A renal artery PSV is 250 cm/s and the aorta PSV is 40 cm/s, giving a ratio of 6.25. This exceeds both PSV and ratio thresholds and supports hemodynamically significant renal artery stenosis. Confirm the sample is at the stenosis, not in a tortuous segment, and check the distal waveform.
Traps
Do not diagnose stenosis from color aliasing alone. A normal PSV does not exclude distal or accessory renal disease. Respiration changes mesenteric velocities; aortic aneurysm size must be measured outer wall to outer wall, not from color.