Esophageal replacement by allogenic aorta in a porcine model

Abstract

Esophageal replacement is a challenging problem requiring complex reconstruction. In response to the recent success of tracheal replacement by fresh allogenic aorta in humans, we assessed in a pig model the feasibility of circumferential segmental esophageal replacement by a fresh aortic allograft. A 4-cm long aortic allograft was interposed after a circumferential 2-cm long resection of the cervical esophagus in 18 minipigs. Anastomoses were protected temporarily by self-expanding polyester-silicone stents (Polyflex; Boston Scientific, Montigny-le-Bretonneux, France). No immunosuppression was given. When stenosis occurred after stent removal or migration, a new stent was inserted. After clinical and endoscopic evaluation, pigs were killed sequentially at 1, 3, 6 and 12 months for analysis. Mortality during the first month was 33%. Four animals died from stent migration during the entire follow-up. Maintenance of a lumen through the graft area by a stent was necessary for 6 months, in order to avoid stenosis occurrence. After the sixth postoperative month, esophageal lumen remained patent until the twelfth month, allowing an apparently normal feeding and weight gain. Gradual contraction of the graft area was observed with time. Sequential histologic analysis showed an inflammatory reaction that decreased with time and a progressive epithelialization of the graft area which became similar to native esophageal epithelium. After 12 months, islets of smooth muscle organized as fascicules or in bundles were visible within the fibrotic tissue. Short esophageal replacement by fresh aortic allograft, under the cover of a temporary maintenance of the lumen of the graft area by an esophageal stent, allows the restitution of a patent esophageal lumen and nutritional autonomy.