What are the anatomic criteria for the Gore Excluder (Endovascular Aortic Aneurysm Repair device) and Gore Conformable (Endovascular Aortic Aneurysm Repair device) AAA (Abdominal Aortic Aneurysm) endoprostheses?

Anatomic Criteria for Gore Excluder and Gore Conformable AAA Endoprostheses

The Gore Excluder Conformable AAA Endoprosthesis is approved for proximal aortic neck angles ≤90° with ≥15 mm neck length OR angles ≤60° with ≥10 mm neck length, representing a significant expansion beyond conventional EVAR criteria which typically require neck angles <60° and lengths >15 mm. 1

Standard Gore Excluder (C3) Anatomic Requirements

Proximal Neck Criteria

• Neck length: ≥10-15 mm required for adequate proximal seal 2
• Neck diameter: <30 mm maximum to provide adequate proximal graft seal 2
• Neck angulation: <60° is the traditional IFU threshold, though real-world practice shows deployment at higher angles 3
• Thrombus/calcification: <90% circumferential coverage of the proximal neck diameter is preferred, as greater burden increases risk of type I endoleak and migration 2

Distal Landing Zone

• Location: Within one or both common iliac arteries 2
• Access vessels: Adequate iliac artery diameter and tortuosity to accommodate delivery system 2

Gore Excluder Conformable AAA Endoprosthesis - Expanded Criteria

Key Anatomic Advantages

The Conformable device specifically addresses hostile neck anatomy that excludes >50% of patients from conventional EVAR 2:

Proximal Neck Specifications:

• Severe angulation option 1: Neck angles ≤90° with ≥15 mm neck length 1
• Severe angulation option 2: Neck angles ≤60° with ≥10 mm neck length (shorter neck tolerance) 1
• Real-world deployment: Successfully used in necks with mean angulation of 83° and mean length of 2.1 cm 4
• Clinical series data: Demonstrated technical success in necks with 70-90° angulation 4, 5

Unique Device Features Enabling Expanded Anatomy

• Repositionability: Allows precise deployment adjustment, critical in hostile anatomy 6, 1
• Conformability: Adapts to severe angulation without compromising seal 6, 1
• Optional angulation control: First device offering active control system for severe neck angles 6, 5

Critical Technical Considerations

Oversizing Strategy

• Standard practice: Mean graft oversize of 23.5 ± 9.6% used in angulated necks >60° 3
• Important caveat: Degree of oversizing was NOT a predictor of type IA endoleak in angulated anatomy 3
• Neck length and angle: Neither parameter predicted type IA endoleak when proper technique employed 3

Deployment Technique for Conformable Device

When deploying in severe angulation (≥70°):

• Aggressive initial positioning: Start deployment over the level of renal arteries due to risk of distal migration on external curvature 5
• Through-and-through access: Routine axillary-femoral approach recommended 5
• Renal artery protection: Preventive cannulation of lower renal artery if short neck (<15 mm) present 5
• Redeployment expectation: Necessary in most cases to achieve precise positioning 5

Common Pitfalls and How to Avoid Them

Patient Selection Errors

• Pitfall: Using conventional EVAR devices outside IFU in severely angulated necks without recognizing increased failure risk 2
• Solution: Long-term studies demonstrate that stent grafts used outside anatomic criteria tested in pivotal trials have increased risk of aneurysm sac enlargement 2

Measurement Technique

• Pitfall: Measuring aortic diameter in axial plane rather than perpendicular to vessel centerline, overestimating diameter in tortuous anatomy 2
• Solution: Use 3-D multiplanar reformatted images measuring perpendicular to aortic centerline 2
• Measurement variability: Inner-to-inner measurements can be 3-6 mm smaller than outer-to-outer 2

Imaging Requirements

• Preoperative planning: CT angiography is generally preferred when AAA reaches intervention threshold to confirm diameters and detail anatomy 2, 7
• Inadequate assessment: Relying on angiography alone for AAA size assessment is inappropriate 7

Early Outcomes Data

Conformable Device Performance

• Technical success: 100% in initial clinical series 1
• 30-day endoleak rates: Type Ib and type II endoleaks observed, with type Ib requiring reintervention 1
• Mid-term follow-up: No type IA endoleak or migration at median 5.2 months in severe angulation cases 5
• Mortality: No AAA-related mortality in early series 1

Surveillance Requirements

• Post-EVAR imaging: Recommended at 1 month and 12 months, then yearly with CT/MR and duplex ultrasound 2
• Rationale: Higher complication and reintervention rates compared to open repair necessitate lifelong monitoring 2