A 58-year-old man with a 50-pack-year smoking history and COPD presents with a 6-week history of a pulsatile abdominal mass and progressive back pain. On examination, a tender, expansile mass is palpated above the umbilicus. CT angiography reveals a 5.5 cm infrarenal abdominal aortic aneurysm (AAA) with no evidence of rupture. The patient is haemodynamically stable. Which of the following is the most appropriate management?

Explanation

## Management of Unruptured Infrarenal AAA ### Clinical Context This patient presents with an **unruptured, symptomatic infrarenal AAA of 5.5 cm**. The presence of back pain suggests the aneurysm is expanding or causing local inflammation, which is an indication for intervention regardless of size. ### Key Decision Points **Key Point:** AAAs ≥5.5 cm have a high risk of rupture (approximately 10% per year) and warrant intervention. Symptomatic AAAs (pain, tenderness) require urgent repair even if <5.5 cm. **Key Point:** The choice between open repair (OR) and EVAR depends on anatomical suitability and patient fitness. EVAR is now the preferred first-line approach for suitable anatomy due to lower perioperative morbidity and mortality. ### Why EVAR is Preferred Here 1. **Anatomical suitability:** Infrarenal AAA is ideal for EVAR (requires adequate proximal neck length and iliac access) 2. **Lower perioperative risk:** EVAR has 30-day mortality of 1–2% vs. 4–6% for open repair in fit patients 3. **Faster recovery:** Shorter hospital stay, earlier mobilization 4. **Risk stratification:** The patient's age (58) and COPD history make minimally invasive approach preferable 5. **Durability:** Long-term outcomes are now well-established; endoleak rates are manageable with surveillance ### Treatment Algorithm ```mermaid flowchart TD A[Unruptured AAA ≥5.5 cm or symptomatic]:::outcome --> B{Anatomically suitable for EVAR?}:::decision B -->|Yes| C[Risk stratify patient]:::action B -->|No| D[Open surgical repair]:::action C --> E{Fit for intervention?}:::decision E -->|Yes| F[EVAR]:::action E -->|No| G[Conservative management with surveillance]:::action F --> H[Lifelong imaging surveillance for endoleak]:::action D --> I[Perioperative optimization, then OR]:::action ``` ### Surveillance After EVAR - **CT angiography:** 1 month, 6 months, then annually - **Duplex ultrasound:** Alternative for follow-up if renal function preserved - **Endoleak detection:** Type I (seal failure) and Type III (modular separation) require re-intervention; Type II (branch vessel backfill) often managed conservatively **High-Yield:** EVAR is now the standard of care for infrarenal AAA in anatomically suitable patients, regardless of age, due to superior perioperative outcomes and acceptable long-term durability. **Clinical Pearl:** Back pain in an AAA patient is a red flag for expansion or impending rupture—it mandates urgent intervention, not observation.