ebjlady2, you may want to look at the study (or at least the Abstract) entitled "Hancock II Bioprosthesis for Aortic Valve Replacement: The Gold Standard of Bioprosthetic Valves Durability?" by Tirone E. David, MD, Susan Armstrong, MS, Manjula Maganti, MS, in Ann Thorac Surg 2010;90:775-781, abstract at ats.ctsnetjournals.org/cgi/content/abstract/90/3/775? .
In it, a top heart-surgery team shows remarkably good long-term results from the Hancock II "piggy" valve, especially in us over-60's. I think you'd have a reasonable chance of hitting your statistical life expectancy with the same valve, though there are never any guarantees in any of this. The only other tissue valve I know that has published durability results almost that long-term and almost that good, is the CE Perimount (mostly the older model, because I think the Magna is too new to have long-term results). The comparison between the two is discussed in great detail in the last few pages of the "Gold Standard" article -- which unfortunately is only available online for $$, maybe $30.
There are newer and "fancier" valves out there, and they MAY end up lasting even longer -- the ATF (?) valve made from a horse pericardium seems impressive to me, but quite new -- but for pure proven durability, the Hancock II does seem like the "Gold Standard". So if you really want to avoid ACT and ALSO have a good chance of avoiding the need for a re-op, it might be a good shot. Of course, there's also a reasonable chance that one of the two cath-implanted valves now being used in Europe and/or Japan and/or tested in the US will become a mainstream option by the time you need a re-do, if you ever do.
