Nine days after femoral artery catheterization, a compressible 1.5 cm mass that enlarges to about 3 cm and refills after pressure—what does this indicate?

Femoral Artery Pseudoaneurysm

This clinical presentation—a compressible, pulsatile mass appearing 9 days post-catheterization that enlarges to 3 cm, decreases with pressure, then refills—is diagnostic of a femoral artery pseudoaneurysm requiring immediate duplex ultrasound confirmation and definitive treatment given its size ≥2.0 cm. 1, 2

Diagnostic Confirmation

The described physical findings are pathognomonic for pseudoaneurysm:

• Compressibility with refilling indicates a pulsatile hematoma communicating with the femoral artery through a defect in the arterial wall 1
• The "to-and-fro" behavior (decreasing to 2 cm with pressure, then re-expanding to 3 cm) reflects the characteristic flow pattern through the pseudoaneurysm neck 3
• Physical examination alone misses >60% of pseudoaneurysms, so duplex ultrasound must be performed immediately to confirm diagnosis, measure size precisely, and document the characteristic "to-and-fro" Doppler waveform 2, 4

Critical Risk Assessment at 9 Days Post-Procedure

At this timepoint with a 3 cm lesion, you face substantial risks:

• All untreated pseudoaneurysms inevitably enlarge, increasing rupture risk as they expand 2
• Rupture with active hemorrhage, skin erosion, or expansion into adjacent soft tissue creates an unstable situation demanding emergency surgical repair 1, 2
• Venous compression can cause deep vein thrombosis; arterial compression may produce limb ischemia 2
• Nerve compression produces neuropathy 2
• Distal thromboembolism from mural thrombus within the cavity can occur, though exact incidence is uncertain 2

Treatment Algorithm for 3 cm Pseudoaneurysm

For this ≥2.0 cm pseudoaneurysm, aggressive treatment is mandatory—observation is not appropriate. 1, 2

First-Line Definitive Treatment

Ultrasound-guided thrombin injection is the preferred initial therapy:

• Achieves approximately 93% technical success even in patients on antithrombotic therapy 2
• Requires injection of 100-3000 international units of thrombin 5
• Distal thromboembolism occurs in <2% of cases 2, 5
• Can be performed despite continuation of low-dose aspirin (75-100 mg daily), which does not impede pseudoaneurysm thrombosis 2

Alternative Minimally Invasive Option

Ultrasound-guided compression therapy yields 75-90% success for accessible pseudoaneurysms:

• Requires prolonged compression (average 104 minutes in one series) 6
• Higher recurrence rate in patients receiving anticoagulation 3
• Associated with patient discomfort and 3.6% complication rate 3
• Less effective than thrombin injection for larger lesions 2

Surgical Repair Indications

Proceed directly to open surgical repair if:

• Thrombin injection or compression therapy fails or the pseudoaneurysm recurs 1, 2
• Any signs of rupture, active bleeding, or skin erosion are present 1, 2
• Venous thrombosis or painful neuropathy from compression develops 2, 5
• The patient has symptomatic expansion, severe pain, or a rapidly enlarging mass 5

Management While on Antiplatelet Therapy

Do not discontinue aspirin in patients with recent cardiac catheterization:

• ACC/AHA Class I, Level A recommendation mandates continuing low-dose aspirin (75-100 mg daily) after cardiac procedures to prevent major adverse cardiovascular events and stent thrombosis 2
• Continuing aspirin does not impede spontaneous thrombosis of small pseudoaneurysms and does not reduce thrombin injection efficacy (94% success rate maintained) 2

Post-Treatment Monitoring

After successful thrombin injection or compression:

• Confirm closure with duplex ultrasound at 24 hours 7
• Mandatory follow-up ultrasound at 1 month to verify persistent thrombosis 1, 2
• If pseudoaneurysm persists at 2 months despite initial treatment, proceed to surgical repair 2, 5

Common Pitfalls to Avoid

• Never rely on physical examination alone—imaging is obligatory whenever pseudoaneurysm is suspected, as clinical assessment misses the majority of cases 2, 4
• Do not observe a 3 cm pseudoaneurysm—conservative management is appropriate only for asymptomatic lesions <2.0 cm, and even those require strict activity restriction and monthly ultrasound surveillance 1, 2
• Do not delay treatment if any compressive symptoms, pain, expanding mass, or skin changes develop—these mandate urgent intervention 2, 5
• Pseudoaneurysms are easily confused with simple hematomas or abscesses on clinical examination, underscoring the absolute need for duplex ultrasound confirmation 2, 5