Experimental evaluation of a hybrid thoracic aortic prosthesis in a pig model

 Relevance. The frozen elephant trunk technique is recognized as a safe and effective method of surgical treatment for aneurysms and dissections of the thoracic aorta. The hybrid prostheses, available on the territory of the Russian Federation, are foreign-made, characterized by a high price, and, accordingly, unpopular. Due to unavailability of domestic hybrid prostheses in the home market, the development of domestic prosthesis is the key  point to further progress in aortic surgery in the Russian Federation.

Aim. The aim of the study was to evaluate the implantation characteristics of prototype hybrid thoracic aorta prosthesis in the pig model and the transformation of the prosthesis in the postoperative period.

Material and Methods. The hybrid prosthesis consists of two parts including the vascular part and a stent graft. The prosthesis is made of Dacron and Z-shaped nitinol wire stents. A Landrace pig aged six months with body weight of 120 kg underwent open reconstruction of the descending aorta through the left-sided lateral thoracotomy, under conditions of extracorporeal bypass with a roller pump from the left subclavian artery to the descending aorta. The animal was removed from the experiment after six months as planned. The macro- and microscopic evaluation of the removed implant was performed.

Results. The technical success of implantation of hybrid stent graft prototype was confirmed. Macroscopy of the stent graft, removed after six months, demonstrated a complete coverage of the neointimal inner surface of the synthetic prosthesis. The lumen of the product was patent. Histological examination revealed the neointima presented as a structured connective tissue without signs of inflammation. The luminal surface was lined with a single layer of evenly spaced endotheliocytes. The thickness of the neointima in the vascular part was significantly greater than in the stent-graft part (p = 0.0121).

Conclusion. The study demonstrated the technical feasibility of implantation of the prototype hybrid prosthesis developed by Angioline Research LLC. The effectiveness of sealing impregnation was confirmed by the absence of active signs of bleeding during the perioperative and early postoperative stages. The prosthesis demonstrated satisfactory bio- and  hemocompatibility.  

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