Stent-graft design: the good, the bad and the ugly

10 years of experience with endovascular AAA repair has yielded important information regarding the relationship between stent-graft design and stent-graft performance. Commercially available systems differ in important ways. General conclusions regarding endovascular AAA repair need to be qualified by reference to a specific system, or systems. Nevertheless, one can draw conclusions regarding the observed effects of certain design features, some of which are common to several devices. For example: tapered, trackable delivery systems (< or =20 French in diameter) rarely fail to traverse tortuous iliac arteries: transmural barbs provide the most secure means of proximal attachment, column strength is of little value; proximal stent migration is becoming the primary late failure mode; modular stent-grafts are more versatile than unibody stent-grafts; fully-stented graft limbs are less prone to thrombosis than unstented graft limbs, iliac implantation and low porosity are associated with lower rates of aneurysm dilatation in the absence of endoleak (endotension); any movement between the angle of a stent and the overlying fabric will lead to graft erosion; unpolished (black) Nitinol is prone to fracture; and a long trunk/short limb combination is more stable than a short trunk/long limb combination.