A 70-year-old obese man underwent cardiac catheterization for coronary stenting. He received dual antiplatelet therapy with the use of glycoprotein inhibitors during the intervention. He presented a week later to his cardiologist with increasing painful groin swelling. He underwent a duplex examination of the groin that demonstrated a pseudoaneurysm (PSA) measuring approximately 4 cm with a long narrow neck and a “Yin-Yang” or “to-and-fro” sign (Figure 34-1A). Doppler evaluation of the neck of the aneurysm demonstrated arterial waveforms (Figure 34-1B).

He was treated with percutaneous ultrasound-guided thrombin injection (UGTI) into PSA sac that led to resolution of his symptoms with occlusion of flow into aneurysm sac (Figure 34-1C).

A true aneurysm of the arterial system involves all the three layers of an artery while PSAs do not involve all the three layers. It is simply a pulsatile hematoma with active extravasation of blood around the arterial wall. The hematoma may tamponade the bleeding artery allowing a spontaneous closure of the PSA sac. Alternatively, it may form a well-organized fibrous capsule with persistent flow maintained at the center of the sac via a neck communicating with the arterial lumen.¹ A PSA may expand, rupture, lead to distal embolization, or cause arterial compression with resultant ischemia.

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  Femoral artery PSAs are the most common complication resulting after percutaneous procedures.

  
  
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  The incidence has been reported between 0.5% and 9% of all interventional procedures.²

  
  
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  Other causes include various surgical interventions as well as blunt and penetrating trauma.^{3,4, and 5}

There is a steadily increasing frequency of PSAs due to increased number of percutaneous interventions.¹

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  Factors that increase the likelihood for a PSA include

  
  
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  Large sheath size

  
  
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  Interventional procedures compared to diagnostic evaluation that require large caliber sheath access

  
  
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  Poor technique (low or high femoral artery puncture)

  
  
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  Obesity and significantly calcific arteries

  
  
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  Need for anticoagulation

  
  
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  Female gender

  
  
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  Chronic renal failure requiring hemodialysis^{6,7, and 8}

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  Symptoms: Painful pulsatile mass is the common presentation. Continued expansion may lead to ecchymosis, cutaneous ischemia, and skin necrosis. Expansion may lead to compression of surrounding femoral nerve, weakness of hip flexion, swelling due to femoral vein compression. Distal embolization and acute limb ischemia are rare but not uncommon. Rupture can lead to cardiovascular collapse and death. Patients can have a large retroperitoneal bleed without any swelling in the groin due to high femoral arterial puncture.

  
  
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  Signs: Physical examination may elicit tenderness, a thrill or a pulsatile mass. Additionally, a bruit may also be auscultated if there is a coexistent arteriovenous fistula. Peripheral pulses should be assessed and ankle-brachial indices (ABIs) obtained to ensure that there is no distal embolization.