Enxertos valvares aórticos homólogos: estudo experimental em c？es

the aim of this research was to develop an experimental model, with dogs, to study homologous aortic valve grafts. a group of twenty randomly selected dogs was divided into two subgroups of tem, being group i the donor group and group ii the recipient group. the surgical approach to the animals of group i was through a median thoracotomy through which the heart was explanted. the homograft aortic valve was trimmed and prepared. the technical procedures are described step by step. all the dogs from group ii had a median laparotomy performed and the homograft was immediately implanted in the abdominal aorta below the emergence of both renal arteries. the median weight of group i dogs was 5.5 ± 1.7 kg and 11.9 ± 2.3 kg for group ii. the abdominal aorta's diameter was 8.8 ± 1.2 mm and the one of the homograft valve was 11.8 ± 1.4 mm. the only problem during surgery was the injury of the lymphatic ducts in four cases, with no consequences after its ligation. the mean period of occlusion was 37.6 ± 13.3 minutes. one animal died ten days after surgery due to inferior mesenteric infarction; a second one was sacrificed 14 days after surgery due to a serious infection of the surgical wound; a third animal escaped from the bioterium 25 days after surgery. all the remaining dogs were submitted to a new laparotomy after 30 days. the abdominal cavity was analyzed for adhesions and grafts' haematoma and the aortic pressures proximal and distally to the graft registered (mean gradient was 2.5 mm/hg). the cusps and the graft were satisfactory, except in two cases, due to partial fixation of one of the cusps; thrombi appeared on all the other two sinuses of valsalva. concluding it was felt that this experimental model is compatible, for future studies, of aortic valve homologous grafts.