Structural failures in abdominal aortic aneurysm stentgrafts: Threat to durability and challenge to technology

A variety of structural defects or failures have appeared in the majority of commercially developed stentgrafts for endoluminal abdominal aortic aneurysm (AAA) repair. Some have resulted in device withdrawal; others have been dealt with by device modification. Newer devices have been designed to avoid some of these failure modes but, because many have not become apparent until as late as 2 years, these corrective measures will require long-term follow-up to establish device durability. Typically, routine surveillance has missed these problems or discovered them late and, when fully investigated, most structural problems have been more prevalent than initially suspected and/or increased with time. However, analyses documenting the full extent and clinical consequences of these structural failures have not been openly reported. This lack of information, and the nature of the structural failures themselves, have undermined confidence in the durability of endovascular aneurysm repair (EVAR), mandated indefinite periodic surveillance, and further increased its costs. Prospects for controlling the described failure modes in the future are good in terms of most device- and operator-specific causes, but aneurysm-specific causes may be more difficult to overcome. Until durability is established by improved technology and long-term follow-up, a more conservative application of EVAR has been suggested, with its use limited primarily to patients with large AAAs (>5.5 cm diameter), favorable anatomy for EVAR, and associated comorbidities that significantly increase the patient's risk for open repair as well as decrease their longevity outlook. The history of these structural failures and the corrective measures taken, as well as their current impact on EVAR are presented in this article.