The use of a valved conduit in the aortic position removes the ability to use the top-contender tissue valves, either porcine or bovine. The valved conduit is a special assembly made in a different way, in which the valve is incorporated into a prefashioned tube.
This is difficult enough that Medtronics doesn't certify their VCs for aortic replacement. They have a different assembly, the Freestyle, which includes portions of the descending aorta and uses the new technologies. However, Ted requires replacement of part of his ascending aorta now, so that would not fill the entire need. The other surgical option for tissue is to piece things together (valve and Dacron) during the surgery, which is done fairly often in the US.
I will not be here during Ted's surgery, but I want you to know that on Tuesday the 10th, I will take the time to ensure that he is in my thoughts, and you as well, Cindy.
Very best wishes,