Korean J Thorac Cardiovasc Surg.
2007 Jan;40(1):1-7.
Histologic Changes of the Immunologically Untreated Xenogenic Valved Conduit
- Affiliations
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- 1Department of Thoracic and Cardiovascular Surgery, Samsung Medical Center, College of Medicine, Sungkyunkwan University, Korea.
- 2Department Pathology, Seoul National University College of Medicine, Korea.
- 3Department of Thoracic and Cardiovascular Surgery, Seoul National University Hospital, Korea. wongon@plaza.snu.ac.kr
Abstract
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BACKGROUND: It has been shown that the endothelium of cardiac valves and adjacent great vessels have a reduced immune reaction compared to other vessels. We investigated the clinical feasibility of using immunologically untreated xenogenic valves, in a pig-to-goat pulmonary valve conduit implantation model.
MATERIAL AND METHOD: Porcine pulmonary valve conduits were prepared without specific immunologic treatment and implanted into the right ventricular outflow tract of goats while undergoing cardiopulmonary bypass. Two goats each were assigned to the following observation time intervals: one day, one week, three months, six months and twelve months. Echocardiographic examinations were performed prior to sacrifice of the goat to evaluate pulmonary valve function. After the xenograft specimens were retrieved, histological changes were evaluated microscopically.
RESULT: Ten of the twelve animals survived the predetermined observation time intervals. Aneurysmal dilatations, of the anterior wall of the implanted pulmonary artery, were observed at each of three and twelve month-survival animals. A variable degree of pulmonary valve regurgitation was observed on echocardiography. However, valve stenosis, thrombotic occlusion and vegetation were not seen. Microscopically, the nuclei of the donor tissue disappeared as a result of pyknosis and karyolysis; however the three components of the implanted xenografts (the pulmonary artery, the valve and the infundibulum) were gradually replaced by host cells over time, while maintaining their structural integrity.
CONCLUSION
Immunologically untreated xenogenic pulmonary valve conduits were replaced by host cells with few observed clinical problems in a pig to goat pulmonary valve implantation model. Therefore, they might be an alternative bioprosthesis option.