Classification of endoleaks after endovascular aneurysm repair.

Type I (Perigraft ) : (Ia) perigraft flow occurring proximally,
(Ib) perigraft flow occurring distally, and (Ic) perigraft flow around
an iliac artery occlusion device.

 Type II(Branch):Branch arteries back-bleed because of collateral flow. These
endoleaks include (IIa) back-bleeding inferior mesenteric artery
and (IIb) back-bleeding lumbar artery.

Type III :Flow persists between the segments of a modular graft and
include (IIIa) leaks between iliac limbs or an iliac limb and main
body component and (IIIb) leaks between main body components.

Type IV(Porosity) :Flow is present through endograft material (graft porosity).

 Type V(Endotension) :(V), Persistent or recurrent pressurization of the
aortic aneurysm exists in the absence of demonstrable endoleak.

References
Eliason JL, Upchurch GR Jr. Endovascular abdominal aortic aneurysm
repair. Circulation. 2008;117:1738–1744.