Wallgraft endoprosthesis: initial canine evaluation

This study evaluated the in vivo deployment and the healing characteristics of a self-expanding endoluminal graft [Wallgraft (WG) Endoprosthesis] in a canine (n = 22) aorta. The WG consisted of a 10 or 12 mm x 7.5 cm Wallstents (Schneider, Inc.) covered with polyethylene terephthalate (Dacron) graft material. Twenty-two WGs were deployed using fluoroscopic guidance. Devices were oversized approximately 10 per cent. Intravascular ultrasound (IVUS) was repeated, and balloon expansion along the length of the WG was performed to assure maximum expansion. WGs were evaluated with IVUS, angiography, and histology at 14 (n = 4), 30 (n = 4), 90 (n = 4), 180 (n = 5), and 365 (n = 5) days. Predeployment aortic diameters were 9.9 +/- 1 mm. Mid-WG diameters were 9.0 +/- 0.8 mm before balloon dilation and 9.2 +/- 0.5 mm after dilation with 8- (n = 1), 10- (n = 16), and 12- (n = 5) mm balloons. Twenty-two of 23 devices were deployed accurately with good apposition and aortic flow after deployment. On explant, all of the covered grafts were widely patent on IVUS and angiogram. Four explants demonstrated gaps (due to WG taper) between the proximal or distal ends of the graft on IVUS. The device length (9.1 + 0.5 cm) did not change significantly after deployment. Histologically at 6 months and 1 year the lumens were cell-lined. Scanning electron micrography demonstrated endothelial-like cells. This study demonstrates the ability of a WG to be accurately deployed and maintain excellent patency. Balloon expansion after deployment did not significantly increase the diameter. Clinical evaluation of this device is in progress.