BIG POPS

Written by: Dr. Ellen Chow

Edited by: Dr. Joann Hsu

Case Presentation


An 84 y/o M with history of HTN, HLD, and PAD was sent to the ED by his primary care physician. He had an outpatient ultrasound yesterday for a month-long history of bilateral lower extremity pain that was worse on the right side with swelling. The pain was not associated with walking or rest. Denies chest pain, shortness of breath, syncope, or history of blood clots ever. Not on anticoagulation.

Bedside ultrasound showed:

The left popliteal artery shows an aneurysm with blood flow. A blood clot is visualized, obstructing part of the artery.

Here is the same view with color doppler, further showing the arterial flow within this aneurysm.

The right popliteal artery also has an aneurysm, with some preserved arterial flow.

Here is the same right popliteal aneurysm shown with color doppler to highlight the preserved flow.

Popliteal Artery POCUS

  1. Popliteal arteries are usually visualized during a DVT ultrasound study, using a linear probe

  2. Position the patient so that they are in slight (approximately 120 degrees) knee flexion so that you can easily fit and manipulate the probe in the popliteal fossa

  3. The popliteal vein is usually above the popliteal artery (“Pop on top”) when performing a DVT study distally. As you scan distally down the leg, you will eventually see the trifurcation of the popliteal vein above into the peroneal, posterior tibial, and anterior tibial veins. The popliteal artery will have some small branches to perfuse the anterior knee, but will eventually bifurcate into the anterior and posterior artery. 

Popliteal Artery Aneurysms

  • They are the most common true peripheral artery aneurysm

  • About 40% of pts with popliteal artery aneurysms will have a concurrent AAA

  • About 40% of pts will be asymptomatic

  • Symptoms vary but include claudication, acute ischemia, mass effect

  • Rupture is rare (5-18%)

  • Aneurysms > 2 cm are at higher risk for VTE and/or acute ischemic events

  • Management:

    • Assess other vessels given association with other large vessel aneurysms

    • Surgical intervention if the patient is symptomatic or if the aneurysm is > 2 cm

    • Antiplatelet therapy is usually started by vascular surgery for cardiac disease risk reduction

    • If the patient is presenting with acute limb ischemia, emergently consult vascular surgery and start a heparin drip for anticoagulation

    • Otherwise, patients should be given vascular surgery follow up

Case Conclusion

The patient received a radiology-performed ultrasound of the bilateral lower extremities which confirmed bilateral popliteal aneurysms, 3.7 cm on the right and 2.1 cm on the left. There were no visualized DVTs. Fortunately, the patient had a CT of the abdomen and pelvis in the ED from one week ago for an unrelated complaint that showed just a mildly dilated distal abdominal aorta of 2.6 cm with tortuous, ectatic iliac arteries with the right common iliac artery measuring 1.9 cm and the left common iliac artery measuring 1.4 cm. Given that he had perfused and neurovascularly intact legs, the patient was eventually discharged from the ED with a vascular surgery follow-up appointment scheduled for the next week. 

Happy scanning!!

References

Reed, Amy B., and John F. Eidt. "Popliteal artery aneurysm." U: Mills JL, Eidt JF, Collins KA, eds. UpToDate. Waltham (MA): UpToDate Inc (2018). 

“Ultrasound Assessment of Abdominal Aortic Aneurysms.” Medscape, reference.medscape.com/features/slideshow/ultrasound.

The Use of Point-of-Care Ultrasound (POCUS) in the Diagnosis of Deep Vein Thrombosis - Scientific Figure on ResearchGate. Available from: https://www.researchgate.net/figure/The-three-types-of-transducers-used-in-point-of-care-ultrasound-POCUS-The-linear_fig1_354242273 [accessed 12 May, 2024]

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