Current Paradigms in Complex Endovascular Aortic Aneurysm Repair (EVAR/TEVAR)

## Introduction Endovascular aneurysm repair (EVAR) and thoracic endovascular aortic repair (TEVAR) have fundamentally transformed the clinical paradigm for abdominal and thoracic aortic pathology. Once associated with substantial morbidity and prolonged intensive care stays, minimally invasive catheter-based stent-graft deployment offers patients durable exclusion of aneurysmal sacs with minimal physiological insult. ### Key Anatomical Considerations 1. **Proximal Neck Geometry**: A secure proximal seal zone requires an adequate infrarenal neck length (ideally > 15 mm), neck angulation < 60 degrees, and absence of circumferential thrombus or severe calcification. 2. **Access Vessels**: Evaluation of the common iliac, external iliac, and common femoral vessels via contrast-enhanced CT angiography (0.75 mm slice thickness) is critical to plan sheath diameter delivery (typically 14–20 French). ### Innovations in Branched and Fenestrated Devices (F/B-EVAR) For juxtarenal and pararenal aneurysms where seal cannot be achieved below the renal arteries, custom-manufactured fenestrated devices allow preservation of the celiac trunk, superior mesenteric artery (SMA), and renal arteries while achieving complete proximal exclusion. ### Endoleak Surveillance - **Type I (Seal Failure)**: Proximal (IA) or distal (IB) leak. Represents high-pressure systemic perfusion of the sac and mandates urgent re-intervention (balloon dilatation, Palmaz stenting, or cuff extension). - **Type II (Branch Retrograde)**: Retrograde flow from lumbar arteries or the inferior mesenteric artery (IMA). Managed conservatively unless sac expansion exceeds 5 mm over consecutive scans.