Abdominal aortic aneurysm occurs when the diameter of the infrarenal aorta reaches 3.0 cm (Fig 1).
The risk of rupture is related with aneurysm size: approximately 5% per year for 5 cm diameter aneurysm and increases to 10% per year for 6 cm aneurysm and to 25% per year for aneurysm 7 cm or larger [1].
Endovascular aortic aneurysm repair was introduced in 1991 and has since been used widely in patients with aortic aneurysm to prevent aneurysm enlargement and rupture [1,
2].
A covered stent is anchored to the proximal and distal ends of the non aneurysmal portions of the artery [2] (Fig 2).
Endovascular repair,
compared to conventional open surgery,
is associated with lower short- term rates of death [1,3] and shorter stays in intensive care units and hospitalization [1,
4].
Fig. 2: Stent-graft. (Up)(A) AneuRx® device (Medtronic Inc, Santa Rosa, CA). This graft is a modular bifurcated stent graft composed of a nitinol exoskeleton and polyester lining.(B) The Gore Excluder® (WL Gore & Associates Inc, Newark, DE). It is also a modular bifurcated device, with a nitinol exoskeleton and a polytetrafluoroethylene graft.(C) The Powerlink® system (Endologix Inc, Irvine, CA). This graft is a unibody device made of polytetrafluoroethylene and a cobalt chromium alloy endoskeleton.(D) The Zenith® device (Cook Inc, Bloomington, IN). It is a modular bifurcated graft with a stainless steel exoskeleton.(Down) Aorto-uni-iliac stent-graft Zenith, Cook.
References: (Up) Donald T Baril, Tikva S Jacobs and Michael L Marin. (2007) Advances in endovascular repair of abdominal aortic aneurysms. Nature Clinical Practice Cardiovascular Medicine 4, 206-213 doi:10.1038
The most common complications of the technique are the endoleaks,
which occur in up to 45-50% of patients [4,
5,
6].
After placing the stent-graft,
if the diameter of aneurysm decreases,
the treatment is considered successful.
If the size of sac enlarges,
an endoleak should be investigated.
Endoleaks are classified into five different types and it is important to understand the etiology of the leak and determining the need for therapeutic approach.