ABSTRACT
The porcine aortic valve was proposed for replacement of the aortic valve by Binet and associates1 in 1965. Originally, they implanted the valve directly in the aortic root, but this technique gave way to the popular stent-mounted porcine heterograft valve. The stent-mounted device could be easily implanted and gave reproducible results. Unfortunately, it soon became apparent that stent-mounted porcine heterografts had less than desirable haemodynamic performance, especially in small sizes. Stent-mounted porcine heterografts also showed calcification and cusp rupture, especially in young patients. David and associates2 came back to the idea of direct insertion of porcine heterografts into the aortic root. The Toronto valve was devised as a stentless valve derived from glutaraldehyde-preserved porcine aortic root with the sinus aorta removed and the exterior of the aorta covered with Dacron cloth for ease of implantation. The Medtronic Freestyle bioprosthesis was designed, tested, and approved for trial implantation in humans in 1992. While the device is similar to the Toronto SPV valve in that it is a glutaraldehyde-preserved porcine aortic root, there are some significant differences in preparation and implantation techniques. This chapter describes the initial trial experience at LDS Hospital in Salt Lake City, UT, USA.
