My piggy valve has been around for almost 30 years now, and its track record over more than 25 years of implantation here in Toronto is nicely documented in an article 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? . Unfortunately, the fulltext is still restricted (~$30), though I have a faxed copy that I've typed several excerpts from in posts here. The last several pages of the article compare their results with all the other published tissue-valve longevity results the authors could find. That section forms the basis of the cheeky "Gold Standard" claim in the title.
The Hancock II is obviously the "2nd-gen" version of Medtronic's Hancock porcine valve, but I think we make comparisons among "classmate" valves at our peril. They're all approved, and they're all way better than a failing native valve. Some seem to last longer than others on average, and any of them can last unusually long or fail early in an individual, no guarantees. Better-than-average surgeons and better-than-average centers probably get better-than-average results, on average, though the data are scanty. The age of the patient is the biggest determinant of average durability (duration of "freedom from Structural Valve Deterioration", in the biz), older patients getting much better longevity than younger ones.
It's not inconceivable that some of the newest-fangled 3rd (or even 4th?) gen valves will turn out to be less durable than earlier ones, despite the best efforts of all inolved. (I'm sure we've all had experiences like that with commercial products, or software, cars, drugs, whatever.) And you've hit on one of the central paradoxes in this important and R&D-intensive field: Everybody wants the most durable valve, but we can only get solid proof of impressive durability for a model of valve that's been in use for a long time. Meanwhile, many providers have come out with newer-fangled models. They don't have a long track record yet, but many of them have features (and vendors) that SUGGEST that they will perform better and/or last even longer. The choice (for those of us who have a choice) is not simple.
Norm - The Gold Standard article does not seem to be restricted anymore. I'm curious...did your valve decision process ever include consideration of the updated model (Mosaic)? As you say, newer models aren't necessarily better, and there have certainly been a few bad outcomes mentioned here regarding the Mosaic, not that they are statistically relevant, but it's enough to give anyone pause. So, just wondering if you went through a Hancock vs Mosaic discussion process, any worries from your surgeon about the 3rd generation changes (Mosaic) or just going with the proven veteran, so to speak?
Matt - My surgeon gave me two tissue valve options - the Edwards Magna that I have and the Medtronic Mosaic. As was said, it seems that these are the most common choices here in the US in recent times, and neither around long enough in their totality of current design to be fully "proven". Not that it much matters, but I think the Edwards Magna, approved in 2003, did not get a key treatment component - ThermaFix - until a year later. The "current" Medtronic Mosaic was approved in 2000, so a few additional years of evidence.
So, at best, only 12 years or so of evidence exists. For 70 year olds, that wouldn't necessarily be that useful, given the track record of the previous generation. But, for patients in their 30's, you know what, 10 years of evidence sounds a lot more useful. But, of course, far fewer patients go with tissue in their 30's so study documentation is tough to find. Now, my normal instinct is to completely ignore any valve longevity forecasts that are produced by the manufacturers themselves. But, in the interest of your question, and the limited time frame for these current models, here's what they have to say:
"...data released in 2003 [
http://ht.edwards.com/resourcegallery/products/heartvalves/pdfs/clinicalcommuniqueaortic.pdf ]indicate that patients 60 years and older who receive Edwards' original Carpentier-Edwards PERIMOUNT aortic valve will have a greater than 90 percent chance of not needing a new valve for 20 years. ""While we are confident in the excellent performance of our existing tissue processes, the addition of the ThermaFix process has been shown in laboratory studies to reduce calcification up to 44 percent beyond Edwards' current tissue treatment alone,"" ..."
"...The Mosaic valve was evaluated in patients who had aortic valve replacement (AVR) and mitral valve replacement (MVR), and with 12 years of follow-up, the study revealed a freedom from structural valve deterioration of 93.3 percent of AVR patients 60 years and older and in 95.3 percent of MVR patients 70 years and older. In addition, hemodynamic performance data showed stability up to 10 years, indicating durability of the Mosaic bioprosthesis over time..."
Straight off their literature, and no background on these studies, so again, bear that in mind. Now, if memory serves, you are actually hoping for valve sparing on Friday anyway, just working on Plan B here, so hope everything works out for the best!