Toshio Matsuhashi MD, PhD, Presenter: Nothing to Disclose

Sachiko Sato MD, Abstract Co-Author: Nothing to Disclose

Kazumasa Seiji MD, PhD, Abstract Co-Author: Nothing to Disclose

Tadashi Ishibashi MD, PhD, Abstract Co-Author: Nothing to Disclose

Takayuki Yamada MD, PhD, Abstract Co-Author: Nothing to Disclose

Shoki Takahashi MD, Abstract Co-Author: Nothing to Disclose

We developed a new microporous covered stent graft with microporous polyurethane film, in which its luminal surface was flat and its outer surface coated with FK506 to prevent neointimal hyperplasia. We evaluated its physical properties, biocompatibility and feasibility in animal (dogs) study.

Original self-expanding nitinol stent (SENDAI stent: 5∼6 mm in diameter, 20 mm long) was covered with a microporous 15 and 60 μm-thick polyurethane membrane. Micropores were formed with an excimer laser ablation. The pore size was 100 μm and the interpore distance was 250 μm. We measured its kink resistance, radial resistive force and chronic outward force. Bare stents (n=6), microporous covered stents (n=6) and microporous covered stents coated with FK506 (n=6) were implanted into external iliac arteries of adult female beagle dogs. Four weeks after stent implantation, we evaluated its angiographic and histological findings.  

The microporous covered stents showed good kink resistance, good radial resistive force and good patency after stent implantation despite its small diameter. The neointimal coverering of the stent inner wall was confirmed by animal study. Angiography four weeks after stent implantation showed no significant stent-induced stenosis in any of the stents. The intervascular lumen was covered with a new endothelial lining, and no thrombus formation or stent exposure was observed. Histological evaluation showed that the area of neointimal hyperplasia was smaller with the bare stent (4.08± 0.16㎟ ), followed by the FK506-coated covered stent  (5.49± 0.23 ㎟ ), and then the untreated covered stent (6.8± 0.39㎟ ) ; a significant difference ( p<0.05 ) between each group was observed. 

The microporous covered stents showed good kink resistance and good radial resistive force. FK506 treatment on the microporous covered stent was confirmed to be effective in inhibiting neointimal hyperplasia four weeks after stent implantation.

Microporous covered stent graft is a good prosthetic device and is reccommended in the treatment of stenotic vascular lesions and embolization of  peripheral or visceral artery aneurysm.

Matsuhashi, T, Sato, S, Seiji, K, Ishibashi, T, Yamada, T, Takahashi, S, Evaluation of Microporous Covered Stent Graft.  Radiological Society of North America 2008 Scientific Assembly and Annual Meeting, February 18 - February 20, 2008 ,Chicago IL. http://archive.rsna.org/2008/6006379.html