Current status of investigational devices for EVAR: similarities and differences.

Improvements in the design of endovascular grafts are based on lessons learned from difficulties encountered with prior-generation devices. The most common difficulties in device design relate to how the device is delivered and how it can safely and durably fix the aneurysm. This concept is especially true in patients with difficult anatomy. Difficult anatomy, such as small, calcified, tortuous access vessels and short angulated sealing zones, continue to challenge engineers. Currently, the US Food and Drug Administration has approved eight endovascular devices for the treatment of aortic aneurysms: five for abdominal aortic aneurysms and three for thoracic aortic aneurysms. Compared to the first-generation devices approved in 1999, current devices have smaller and more flexible delivery systems. The devices themselves are more flexible and have better fixation than prior-generation devices. This article will focus on the next generation of devices that are not yet approved, but currently under investigation in the United States.