Groin Pseudoaneurysm Management

Treatment Method Decision Guide

Imaging & Diagnosis

• Duplex US confirming PSA with characteristic to-and-fro flow (“yin-yang” sign) on color Doppler
• Measure neck dimensions (length, width) and sac dimensions
• Identify communication with CFA, SFA, or profunda femoris
• Evaluate for AV fistula component (critical — thrombin ineffective if AVF present)
• Distinguish from hematoma (no internal flow), true aneurysm, mycotic aneurysm

Patient Preparation

• Hold anticoagulation if possible (although UGTI is successful regardless of anticoagulation status)
• Labs: CBC, PT/INR, PTT if on heparin
• Pre- and post-procedural ankle-brachial indices and pulse assessment
• Local anesthesia only for thrombin injection (no sedation required)
• Informed consent: discuss risk of distal embolization, recurrence, potential need for escalation

Femoral Artery Anatomy

• Common femoral artery (CFA) — continuation of external iliac artery below inguinal ligament; most common site of catheterization and PSA formation
• Superficial femoral artery (SFA) — anterolateral continuation of CFA after bifurcation
• Profunda femoris artery — posterolateral branch of CFA; PSA can arise from any of these vessels
• PSA location relative to CFA bifurcation is critical for planning — influences neck access and compression approach

Pseudoaneurysm Characteristics

• Neck — communication between parent artery and PSA sac; narrow neck = lower embolization risk during thrombin injection; wide neck = higher risk, may need compression or balloon protection
• Sac — contained rupture of arterial wall; may be unilobed or multilobed
• To-and-fro flow — systolic inflow into sac, diastolic outflow back to artery; pathognomonic on Doppler
• “Yin-yang” sign — swirling bidirectional color flow within the sac on color Doppler

Differential Diagnosis

Hematoma: no internal flow on Doppler, no neck communication. AV fistula: continuous high-velocity turbulent flow between artery and vein, low-resistance arterial waveform. Mycotic (infected) aneurysm: true aneurysmal dilation of vessel wall with periarterial inflammation and gas; requires antibiotics and often surgical management. True aneurysm: involves all three layers of arterial wall (intima, media, adventitia); distinct from PSA where blood is contained only by extravascular tissue.

Alternative Techniques (If Thrombin Fails or Complex PSA)

• Covered stent placement: for multilobed PSA, wide-neck PSA, or thrombin injection failure. Arterial access via contralateral femoral approach; covered stent deployed across the PSA neck to exclude the sac. Moderate bleeding risk.
• US-guided compression repair (UGCR): second-line option. Compress PSA neck under US guidance until flow ceases; maintain 20–30 min. Painful; requires sedation. Lower success rate (51–73% in anticoagulated patients). Not effective for suprainguinal or post-operative PSA.
• Surgical repair: for large PSA with pending rupture, significant hematoma requiring evacuation, failed percutaneous treatment. Complication rate up to 21% (MI, death, bleeding, lymphocele, infection).

Key US Findings

• Gray-scale: hypoechoic/anechoic fluid collection adjacent to femoral artery; may see layered thrombus within sac
• Color Doppler “yin-yang” sign: swirling bidirectional color flow within the PSA sac — pathognomonic
• Spectral Doppler at neck: characteristic to-and-fro waveform — systolic inflow into sac, diastolic outflow back to artery
• Neck visualization: narrow channel connecting sac to parent artery; measure length and width

Needle Placement Landmarks

• Target needle tip at the apex (far wall) of the PSA sac, away from the neck
• Inject into the region where flow is directed away from the neck on color Doppler
• For multilobed PSA: inject the most superficial lobe first; if other lobes do not thrombose, inject each separately
• Compress the neck with the US probe during injection to prevent thrombin reflux into parent artery

Serious Complications

• Distal embolization — thrombin entering parent artery causing downstream thrombosis; rare but limb-threatening; treat with catheter-directed TPA or surgical thrombectomy
• Anaphylaxis to bovine thrombin — reported in patients with prior bovine thrombin exposure; avoid re-exposure; consider human thrombin alternative
• Nontarget arterial thrombosis — intraluminal clot propagation from PSA into femoral artery; may resolve spontaneously or require intervention

Minor Complications & Expected Outcomes

• Recurrence (5–10%) — PSA re-establishes flow after initial thrombosis; repeat UGTI or escalate
• Transient loss of distal pulse — may occur and typically returns within 24h; monitor closely
• Local infection / abscess — rare; one case report of abscess requiring I&D
• Soleal vein thrombosis — reported rarely; monitor for DVT symptoms
• Persistent hematoma — thrombosed PSA sac remains palpable; resolves over weeks

Primary References

• Krueger K, Zaehringer M, Strohe D, et al. Postcatheterization pseudoaneurysm: results of US-guided percutaneous thrombin injection in 240 patients. J Vasc Interv Radiol. 2005;16(1):57–62.
• Morgan R, Belli AM. Current treatment methods for postcatheterization pseudoaneurysms. J Vasc Interv Radiol. 2003;14(6):697–710.
• Padidar AM, Kee ST, Razavi MK. Treatment of femoral artery pseudoaneurysms using ultrasound-guided thrombin injection. Tech Vasc Interv Radiol. 2003;6(2):96–102.
• Kang SS, Labropoulos N, Mansour MA, et al. Percutaneous ultrasound guided thrombin injection: a new method for treating postcatheterization femoral pseudoaneurysms. J Vasc Surg. 1998;28:1120–1121.
• Paulson EK, Nelson RC, Mayes CE, et al. Sonographically guided thrombin injection of iatrogenic femoral pseudoaneurysms: further experience of a single institution. Am J Roentgenol. 2001;177:309–316.
• Pezzullo JA, Dupuy DE, Cronan JJ. Percutaneous injection of thrombin for the treatment of pseudoaneurysms after catheterization. Am J Roentgenol. 2000;175:1035–1040.