Which endoleak type is described as graft fabric/connection failure?

• A. Type I – leak at the proximal/distal seal
• B. Type III – graft fabric/connection failure
• C. Type II – retrograde flow from collateral vessels
• D. Type IV – graft porosity

Answer: (B)

Endoleaks after EVAR are distinguished by how blood reenters the aneurysm sac. The category described as graft fabric or connection failure occurs when a defect in the graft material or a separation at modular connections allows blood to flow directly into the sac, bypassing the intended proximal and distal seals. This creates a high‑pressure leak because the flow comes through the actual graft structure or its junctions, not through collateral vessels. Because of the direct exposure of the aneurysm sac to systemic pressure, it often requires urgent intervention to reestablish a proper seal, typically with relining or extending the stent graft. Other endoleaks include leaks at the ends due to poor sealing, leaks from collateral vessels (retrograde flow), and leaks from graft porosity (usually early and may resolve), but the graft fabric/connection failure is specifically the defect in the graft itself or its connections.