PROPOSAL OF A WORKING LEFT-HEART MODEL WITH A HETEROTOPIC TRANSPLANTATION TECHNIQUE IN RATS

Background: A heterotopically transplanted rat heart model described b y Ono and Lindsey in 1969 has been widely used as a fundamental animal model of heart transplantation. However this ''nonworking'' model is greatly different from the orthotopic heart in view of left ventricula r work, in which the experimental results obtained may not always refl ect the clinical setting with an orthotopic transplanted ''working'' h eart. We herein propose a new ''working'' left heart model in rats usi ng a heterotopic abdominal transplantation technique by modifying the method of Ono and Lindsey. Methods: First, a donor heart graft and a r ecipient were prepared in the conventional fashion. Second, the donor heart was tailored by the ligation of main pulmonary artery and the re moval of tricuspid valve and interatrial septum. Third, the ascending aorta and right atrium of the donor heart were anastomosed to the infr arenal abdominal aorta and to the inferior vena cava of the recipient, respectively. Consequently, the left atrium and ventricle of heart gr aft were loaded with the blood from the right atrium through the inter atrial communication. Results: This surgical procedure required an ave rage of 58 minutes and had negligible operative risk. The donor left v entricle produced a systolic blood pressure almost equal to the recipi ent's aortic pressure and maintained vigorous beat. Conclusions: This model is easily reproducible and would be useful for various studies o n heart transplantation.