Experimental evaluation of the long-term function and durability of various prostheses is required after total excision and subcoronary replacement of the aortic valve. Only short periods of survival have been reported after total replacement of the aortic valve in the dog.1,12,27,28,37 Previous experiments in this laboratory demonstrated that the Holstein-Friesian calf could withstand well the extensive surgical procedure necessary for aortic valve replacement and indicated that prolonged survival following these procedures was possible.23,24
The present study was undertaken to test three types of aortic valve prostheses which were inserted in the subcoronary position in 61 calves.
The 61 calves used in this study had a mean age of 23.3 days and a mean weight of 44.6 kg at the time of operation. They were divided into three groups according to the type of prosthesis employed for aortic valve replacement: group 1, 18 calves, bicuspid prostheses constructed of