Surprises in Store

Severe Aortoiliac Occlusion Discovered in a 45-Year-Old's First Arterial Duplex Exam

Case:

• A 45-year-old female patient is referred for arterial duplex ultrasound of the lower extremity.

• Her physician ordered the ultrasound due to numerous risk factors for peripheral arterial disease (PAD).

Right and Left Lower Extremity Examination:

The B-mode image and color Doppler of the right common femoral artery appeared unremarkable. Surprisingly, however, the spectral Doppler tracing was monophasic. There must be either a proximal stenosis or proximal or distal occlusion, no? Unexpectedly, no occlusion in the right lower extremity was found! What about the contralateral side? As we  are moving on with the left lower extremity at the inguinal region at the level of the common femoral artery, the lumen again appeared unremarkable. The color flow Doppler showed laminar flow, just like the right lower extremity. Are you curious about what the spectral Doppler will display on the left side? – Again, a monophasic waveform was depicted with PW Doppler!

Right common femoral artery:

Left common femoral artery:

Given the finding of bilateral monophasic spectral Doppler waveforms, what would you do next?

A) I will stop my exam here and refer the patient to angiography for a complete workup of the proximal arteries that can not be evaluated with ultrasound.

B) I assess the arteries more distal, especially the popliteal and deep femoral arteries bilaterally.

C) I will continue my scan proximally, scanning the iliac arteries and the aorta.

Solution & explanation below

The correct answer is:

C) I will continue my scan proximally, scanning the iliac arteries and the aorta.

We can suspect aortoiliac stenosis or occlusion at this point since the waveform at the common femoral artery level was monophasic bilaterally. In the next step, we will investigate the more proximal vessels, continuing our exam in the abdomen area. Here, finally, the source of the pathology was found:

As you can see in the B-mode imaging, a calcified plaque in her distal aorta extending into her bilateral common iliac arteries was found. To confirm the suspicion of aortoiliac occlusive disease, the patient was asked if she was having any hip pain when walking -  Yes, she does have hip pain.

Also, take note of the poststenotic aliasing in color flow Doppler, which again confirms the presence of plaque formations.

A stenotic and post-stenotic spectral Doppler tracing was obtained to assess the stenosis's severity. Look at the waveform and peak systolic velocity in the following loops!

Slightly distal to the bifurcation in the right common iliac artery, a Peak systolic velocity of over 500 cm/s was recorded, indicating a severe stenosis.

Of course, in the same way, the left common iliac artery was assessed with spectral Doppler. It showed monophasicity and increased peak systolic velocities, however not as significant as on the right.

Conclusion:

• Diagnosis of aortoiliac occlusive disease.
• Dense plaque formations in the distal aorta and at the entrance into the bilateral common iliac arteries, depicted in B-mode imaging and confirmed with color Doppler, show turbulent flow and aliasing.
• High-grade stenosis of the distal aorta, including the bilateral common iliac arteries, with the right common iliac artery more severely stenosed ( 500 m/s peak systolic velocity ) than the left common iliac artery.

Start learning now:

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