Laparascopic aortic reinforcement and endovascular graft replacement

Abstract

Purpose. The purpose of this study is to evaluate the feasibility of using an external aortic wrap in conjunction with an endovascular graft and to examine the histological response. Methods. Six female pigs, 56–84 kg, underwent laparoscopic retroperitoneal placement of homemade aortic wraps made of Dacron fabric and specially designed straps just below the renal arteries. One week later, stents (one 12 mm × 4 cm Wallstent, two 308 Palmaz stents) were inserted into the infrarenal aorta for preliminary experiments in three pigs, and stent-grafts (13 mm × 5 cm Viabahn) were placed in three pigs. The stents and stent-grafts were aligned with the proximal edge of the aortic wrap, and the balloon was expanded. One animal was prematurely sacrificed. The pigs were followed for 1 to 3 weeks in stent models and for 4 weeks in stent-graft models. The animals were then sacrificed, and abdominal aortas were harvested for histological examination. Results. Technical success was achieved in all animals without complications. One animal was prematurely sacrificed due to cerebral edema secondary to anesthesia. Laparoscopic operative time was 2:42 ± 0:47, and 0:43 ± 0:15 for stent placement. Gross examination of the samples revealed fibrosis external to the device at 1- and 3-week time-points; by 3 weeks the wrap was partially incorporated into the adventitia. Stents and stent-grafts were well incorporated into the intima and no migration was observed. Histological examination of all samples revealed a foreign-body response. Sections taken from beneath the device edges revealed necrosis localized to the muscularis and adventitial aortic junction; however, sections taken from beneath the device body showed no signs of necrosis and the vasa vasorum of the aortic wall was intact. Conclusions. Coordinate laparoscopic external aortic wrapping and stent-grafting is feasible in a porcine model. Aortic wall necrosis was limited. This adjunct to endovascular graft repair of abdominal aortic aneurysms may enhance eligibility for patients with large aortic neck and prevent proximal type 1 endoleak.