Branched hybrid prosthesis: in vivo experimental study

Introduction: The development of a new generation of hybrid prostheses is a way to improve the results of surgical treatment of combined lesions of the aortic arch and descending aorta. Objective: The study was aimed to evaluate the biocompatibility of the new branched hybrid stent graft. Methods: The developed hybrid stent graft consisted of two parts including the vascular part and the stent graft part, which were supplemented with a stented branch for reconstruction of the left subclavian artery. To assess the biological compatibility, a stent graft was implanted in the descending thoracic aorta in 25 large pigs. The results were assessed by surgical mortality, postoperative complications, selective aortic angiography and histological examination after 6 month follow up period. Results: Implantation of a hybrid stent graft was successful in all cases, without complications. In the early period, 3 animals died. The causes of animal death were respiratory failure caused by lung barotrauma, intraoperative bleeding and sudden cardiac death. The remaining pigs survived until the end of the follow up period without complications and were subsequently withdrawn from the experiment. The duration of perfusion by carotid-femoral bypass surgery was 55 [50; 60] minutes. The volume of blood sweating through the vascular part of the prosthesis was 2.28 ± 0.23 ml/cm2/min; the blood loss for the first hour through drain tube was approximately 70.2 ± 8.9 ml. In 6 months after surgery the aortic angiography showed that the main body and branches of the hybrid stent graft were completely passable. No migration, deformation or endolics were observed. The analysis of histological sections showed the presence of a confluent layer of neointima continuously and evenly distributed throughout the luminal surface of the conduits, including lateral branchlets and anastomoses. The neointima was hyperplasized and represented by layers of unidirectional fibroblast cells, its luminal surface was covered with a layer of endotheliocytes. Conclusion: These results demonstrate the technical feasibility and safety of using a new hybrid stent graft with an additional stented branch.