Endovascular stent graft repair for thoracic aortic aneurysms: the history and the present in Japan.

Stent-grafts for endovascular repair of thoracic aortic aneurysms have been commercially available for more than ten years in the West, whereas, in Japan, a manufactured stent-graft was not approved for the use until March 2008. Nevertheless, endovascular thoracic intervention began to be performed in Japan in the early 1990s, with homemade devices used in most cases. Many researchers have continued to develop their homemade devices. We have participated in joint design and assessment efforts with a stent-graft manufacturer, focusing primarily on fenestrated stent-grafts used in repairs at the distal arch, a site especially prone to aneurysm. In March 2008, TAG (W.L. Gore & Associates, Inc., Flagstaff, Arizona, USA) was approved as a stent graft for the thoracic area first in Japan, which was major turning point in treatment for thoracic aortic aneurysms. Subsequently, TALENT (Medtronic, Inc., Minneapolis, Minnesota, USA) was approved in May 2009, and TX2 (COOK MEDICAL Inc., Bloomington, Indiana, USA) in March 2011. Valiant as an improved version of TALENT was approved in November 2011, and TX2 Proform as an improved version of TX2 began to be supplied in October 2012. These stent grafts are excellent devices that showed good results in Western countries, and marked effectiveness can be expected by making the most of the characteristics of each device. A clinical trial in Japan on Najuta (tentative name) (Kawasumi Labo., Inc., Tokyo, Japan) as a line-up of fenestrated stent grafts that can be applied to distal arch aneurysms showing a high incidence, and allow maintenance of blood flow to the arch vessel was initiated. This trial was completed, and Najuta has just been approved in January of 2013 in Japan, and further development is expected. In the U.S., great efforts have recently been made to develop and manufacture excellent stent grafts for thoracic aneurysms, and rapid progress has been achieved. In particular, in the area of the aortic arch, in which we often experience aneurysmal change, but there are no commercially available devices which are urgently needed. Companies are competing keenly to develop devices. To our knowledge, more than 4 manufacturers are involved in the development of functionally new stent grafts in this area. The introduction of branched stent grafts may not be faraway.