EL, what's the source for your "Perimount valve (2003 data claimed around 90% odds of 20 year lifespan for 60 year old and up)"? That sounds longer than the numbers in the study that was referenced in Tyrone David's 2010 "Gold Standard" article.
You know, Edwards seems to use the same trusted source and credit for nearly all of their valve data numbers: "Data on file at Edwards Lifesciences." :rolleyes2:
Whenever I read that citation, I picture a nondescript building bunkered into a hillside with no windows, a single door, multiple security checkpoints, and no means of reproduction allowed. It turns out, though, to Edwards credit, they are more forward with their information than their published citations imply. In fact, only a few days ago, I spoke with someone at Edwards who is supposed to be sending me interim results of ThermaFix valves.
Meanwhile, specific to your question, my point is that Edwards cites (similar to above) 20 year results for the Perimount in nearly every document they publish, but they oddly never publish the actual data. If I recall, Tyrone David even commented on this in his article. But, those 60 year old, 90% numbers are seen very often in their press releases, as was the case when ThermaFix was launched:
http://www.edwards.com/newsroom/Pages/nr20040202.aspx
So, I used the word "claimed" above purposefully, as I did with even more skepticism in the somewhat parallel thread:
http://www.valvereplacement.org/forums/showthread.php?39460-Longevity-of-Tissue-Valves&p=511433&highlight=#post511433
Back to the data, though, when there is a will, there is a way, and I do believe I have found at least a portion of the 20 year data here:
http://ht.edwards.com/resourcegallery/products/heartvalves/pdfs/clinicalcommuniqueaortic.pdf You may want to immediately save to your computer in case someone realizes this information is out there for the general public and immediately removes.
I've never done a side by side comparison with Tyrone David's Hancock numbers, but would welcome any volunteers (hint, hint). I know you've shown a predilection in the past for valve data analysis, Norm, so will look forward to any comments you may have. At a certain stage, I just sort of surrender to the inconclusiveness and/or irrelevance of it all, but perhaps that is more my own laziness on the topic than a data problem!