Endovascular Treatment of Thoracic Aortic Aneurysms

Stent Grafts

There are several stent grafts commercially available and most of them are based on the same principle, with a polyester Dacron or polytetrafluoroethylene (PTFE) graft combined with a Gianturco or Gianturco-like stent of stainless steel or nitinol. The stents are either sutured to the graft or melded into the wall. The ring stents used in the abdominal aorta (Anaconda, Aorfix) are not in clinical use for the thoracic aorta except in one trial. Compared to abdominal aortic stent grafts, the ones used for the descending TAAs are simpler in that they are constructed as straight tubes without the need for complicated branches. Only the Zenith stent graft uses hooks to facilitate the anchoring, whereas the others rely on the radial force. Most stent grafts have several available sizes with respect to diameter as well as the length. Although it is currently possible to custom make a stent graft, using several commercial stent grafts in a trombone technique for the desired length is faster, and with overlapping (>5cm), these devices are durable.

Thoracic stent grafts have evolved since the turn of the century, but dramatic changes have been relatively scarce. There are currently eight CE-marked stent grafts available for treatment of thoracic aortic aneurysms in Europe: Gore TAG, Gore CTAG, Cook Zenith TX2, Medtronic Valiant Captivia, Bolton Relay, Jotec E-vita, and Lemaitre Endofit. In the United States there are fewer FDA-approved devices: Gore TAG, Zenith TX2, Talent, and Medtronic Valiant Captivia. Most design changes have been to make the delivery system smaller, with more flexibility and hydrophilic sheaths.