What is the recommended management for a femoral‑groin pseudo‑aneurysm less than 2 cm in diameter that presents 7 days after catheterisation?

Management of Groin Pseudoaneurysm <2cm at 7 Days Post-Catheterization

For an asymptomatic pseudoaneurysm <2cm presenting 7 days after catheterization, conservative management with strict activity restriction and mandatory ultrasound surveillance at 1 month is appropriate, as approximately 61% of small pseudoaneurysms resolve spontaneously within 7-52 days. 1

Immediate Assessment Requirements

• Confirm the diagnosis with duplex ultrasound immediately, as physical examination alone misses more than 60% of pseudoaneurysms and cannot reliably distinguish them from simple hematomas or abscesses. 1
• Look for the characteristic "to-and-fro" Doppler flow pattern that confirms arterial communication with the pseudoaneurysm cavity. 1
• Measure the exact diameter—the <2cm threshold is critical for determining whether conservative management is safe. 1

Exclude Absolute Indications for Immediate Intervention

Before considering observation, rule out any of the following, which mandate immediate surgical repair regardless of size:

• Active bleeding or rupture 1
• Skin erosion overlying the pseudoaneurysm (signals impending rupture) 1
• Compressive symptoms: venous thrombosis, painful neuropathy, or limb ischemia 1
• Expanding or painful mass 1
• Rapid overnight enlargement 1

Conservative Management Protocol for Asymptomatic <2cm Lesions

Activity Restrictions

• Strict bed rest or minimal ambulation initially, with no heavy lifting, straining, or vigorous activity for 1-2 months during observation. 1
• Weekly clinical assessments combined with ultrasound examinations until complete thrombosis is documented. 1

Anticoagulation Considerations

• Continuing low-dose aspirin (75-100mg daily) does not impede spontaneous thrombosis of small pseudoaneurysms and should not be stopped, particularly in patients with recent coronary stenting or acute coronary syndrome. 1
• However, the spontaneous resolution rate falls markedly when full anticoagulation (warfarin, therapeutic heparin) is required; in these patients, a more aggressive treatment approach is recommended. 1

Mandatory Surveillance Schedule

• Duplex ultrasound at 1 month is obligatory for all conservatively managed lesions. 1
• If the pseudoaneurysm persists at 2 months, proceed to definitive treatment (ultrasound-guided thrombin injection or surgical repair) regardless of size. 1

When to Escalate to Definitive Treatment

First-Line Definitive Therapy: Ultrasound-Guided Thrombin Injection

• If the lesion persists at 2 months, ultrasound-guided thrombin injection achieves approximately 93-94% technical success even in patients on antithrombotic medications. 2, 1
• Administer 100-1000 international units of thrombin directly into the pseudoaneurysm cavity under real-time ultrasound guidance. 2, 1
• Distal arterial thromboembolism occurs in <2% of cases, making this approach safer than prolonged observation of a persistent lesion. 2, 1
• Approximately 5% of pseudoaneurysms recur after initial injection, but recurrent lesions can be safely re-treated with repeat thrombin injection. 2, 1

Alternative: Ultrasound-Guided Compression Therapy

• Achieves 75-90% success for accessible pseudoaneurysms, though it requires longer compression times (20-100 minutes) and may be more painful than thrombin injection. 2, 1, 3
• Success rates are lower for large pseudoaneurysms and in patients on excessive anticoagulation. 3

Surgical Repair Indications

• Failure or recurrence after minimally invasive attempts (thrombin injection or compression). 1
• Development of any symptomatic complications during observation. 1
• Pseudoaneurysm ≥2.0cm at initial presentation (observation is inappropriate for lesions at or above this threshold). 1

Critical Pitfalls to Avoid

• Do not rely on physical examination alone—imaging is mandatory whenever pseudoaneurysm is suspected, as clinical assessment is unreliable. 1
• Do not adopt a "watch-and-wait" approach for lesions ≥2.0cm—conservative management is reserved exclusively for asymptomatic lesions <2.0cm. 1
• Do not skip the 1-month ultrasound follow-up—failure to document resolution or progression creates risk of undetected enlargement and rupture. 1
• Do not stop aspirin in patients with recent coronary intervention—low-dose aspirin does not prevent pseudoaneurysm thrombosis and is essential for cardiovascular protection. 1

Summary Algorithm for <2cm Pseudoaneurysm at 7 Days

1. Confirm diagnosis with duplex ultrasound (measure size, assess for complications). 1
2. If symptomatic or ≥2.0cm → proceed directly to thrombin injection or surgical repair. 1
3. If asymptomatic and <2.0cm → conservative management:
   • Strict activity restriction for 1-2 months 1
   • Continue aspirin if indicated for cardiovascular protection 1
   • Weekly clinical and ultrasound monitoring 1
   • Mandatory ultrasound at 1 month 1
   • If persistent at 2 months → thrombin injection or surgery 1