A 52-year-old male presents with a pulsatile swelling in the femoral triangle. On examination, a continuous 'to-and-fro' murmur is heard. Which is the most common cause of this clinical presentation?

Explanation

## Femoral Triangle Pseudoaneurysm ### Clinical Presentation **Key Point:** A pulsatile swelling in the femoral triangle with a continuous 'to-and-fro' murmur is pathognomonic for a **femoral artery pseudoaneurysm**. ### What is a Pseudoaneurysm? A pseudoaneurysm (false aneurysm) is a collection of blood outside the arterial wall, contained by surrounding tissues rather than by the arterial wall itself. It communicates with the artery via a defect in the arterial wall. ### Most Common Cause: Arterial Puncture **High-Yield:** Femoral artery pseudoaneurysm is the **most common complication of femoral artery puncture** for: - Cardiac catheterization - Coronary angiography - Percutaneous vascular interventions - Femoral artery cannulation ### Mechanism of 'To-and-Fro' Murmur ```mermaid flowchart LR A[Systole: Blood flows<br/>from artery into<br/>pseudoaneurysm sac]:::action --> B[Creates systolic murmur] C[Diastole: Blood flows<br/>back from sac<br/>into artery]:::action --> D[Creates diastolic murmur] B --> E[Combined = 'To-and-Fro'<br/>Continuous Murmur]:::outcome D --> E ``` ### Diagnostic Features | Feature | Pseudoaneurysm | True Aneurysm | Thrombosis | | --- | --- | --- | --- | | Pulsatile swelling | Yes | Yes | No | | To-and-fro murmur | **Yes (pathognomonic)** | No | No | | Ultrasound finding | Yin-yang sign | Fusiform/saccular | Echogenic thrombus | | Cause | Puncture/trauma | Degenerative/inflammatory | Stasis/hypercoagulability | ### Clinical Pearl **Mnemonic — PAVE:** Pseudoaneurysm After Vascular Entry. This is the most common complication of femoral artery access, occurring in 0.5–2% of procedures. ### Incidence Risk Factors - **Procedure-related:** Multiple puncture attempts, large sheath size (>7 Fr), prolonged catheterization - **Patient-related:** Anticoagulation, obesity, female gender, advanced age - **Timing:** Usually presents within days to weeks post-procedure ### Management 1. **Ultrasound-guided compression** — First-line (success rate 80–90%) 2. **Thrombin injection** — If compression fails 3. **Surgical repair** — If conservative measures fail or sac enlarging [cite:Standring Anatomy 42e Ch 77; Harrison 21e Ch 297]