Endoleak classification

SVS reporting standardsCTAEVAR

Persistent flow in the aneurysm sac outside the stent graft after EVAR/TEVAR. Types I and III are high pressure and need prompt treatment.

Type	Source	Imaging clue
Ia / Ib	Inadequate seal at proximal (Ia) or distal (Ib) attachment site. Ic: iliac occluder	Contrast contiguous with graft end; arterial phase
II	Retrograde flow from branch vessels (IMA, lumbar arteries)	Peripheral sac contrast near IMA/lumbar origin; often delayed phase only
III	Graft failure: junctional separation (IIIa) or fabric tear (IIIb)	Contrast adjacent to graft body or overlap zone
IV	Graft porosity, within 30 days of placement	Diffuse blush on completion angiogram
V	Endotension: sac expansion without visible leak	Enlarging sac, no contrast on any phase

Triple-phase CTA (non-contrast, arterial, delayed) separates endoleak from calcification and catches slow type II leaks. Sac growth >5 mm warrants investigation.

Sources

Chaikof EL, Blankensteijn JD, Harris PL, et al. Reporting standards for endovascular aortic aneurysm repair. J Vasc Surg. 2002;35:1048–1060.PubMed ↗

Radessential summarizes published classification systems for practicing radiologists. Summaries are condensed; confirm details against the cited source before relying on them for patient care.