[HSF] Access to AV groove area post bypass Bioprosthesis choice(stentless valves)

Tue Jan 22 04:09:16 EST 2008

Dr Frater

I do not think the technical limitations of implantation was mainly responsible for the mixed or inadequate  results seen with stentless valves but suspect their are many others. Obviously this is not a field I know much about so I am sure you will clarify further and correct (my) misconceptions. The reasons I use 'myth' to describe stentless valves is:

1) How would one explain why the majority of randomized trials of stented vs stenless did not show a difference in LV mass regression or survival? These trials were by invariably undertaken by enthusiasts of the stentless technique who were by definition skilled in the technique and should have achieved the best possible results with stentless valves.

2) Studies from Toronto (where many of the patient-prosthesis and stentless proponents reside) did not show elimination of "patient prosthetic mismatch" by either EOA or direct measurement of gradients in patients receiving stentless valves

3) Most major proponents of the stentless valve - most notably Dr David - now do not recommend their routine use, even in the setting of a small annulus

4) Can advances in stented technology really be the reason why stentless valves 'failed'? Most of the papers on stented vs stenless valves used the carpentier edwards perimount as a control and at that very time the essence of using a stenless valve was to avoid placing a perimount or similar (the standard at the time). So at least the stentless valve - if the hypotheses were correct - should have been superior to the contaprenous stented valves. Additionally, stentless valve was the chosen mode of AV replacement of a number of surgeons active in the 1970s and 1980s such as Barratt-Boyes, Ross and Yacoub but their data did not show convincing (patient survival) benefit compared to then first or second generation porcine valves.

5) The later realization that the long term survival *may* be poorer with the stentless valve because of difficulty in reoperation (and potentially mortality at reoperation) and a seemingly higher early failure rate.

6) Being porcine, the results of these prosthesis may not necessarily mimic that of a (stented) pericardial valve.

I am sure you will provide more insight into the historical evolution of these valves and correct any misinformation.

Thanks

Ani

> To: OpenHeart-L at lists.hsforum.com> Subject: Re: [HSF] Access to AV groove area post bypass Bioprosthesis choice(stentless valves)> Date: Mon, 21 Jan 2008 13:12:55 -0500> From: rwmfglycar at aol.com> CC: > > By doing away with rings and struts a hemodynamic improvement was achieved in small aortic roots. This without doubt resulted in less resistance across the aortic orifice than provided by the contemporaneously available stented valves and this in turn produced greater regression of LV hypertrophy. Since left ventricular hypertrophy is a risk factor for death this seemed like a good idea.> The downside of the several stentless valves on the market was that many surgeons found them difficult to insert. This last issue never went away and there were many surgeons who found them too difficult to use and more or less said there is some regression of hypertrophy with stented valves and that is good enough for me. In the meantime the design of stented valves improved so that the difference in hemodynamic performance became substantially less. Sales of the stentless valves decreased annually until it became economically impossible to maintain the plant needed to continue building them.>    It is unfair to characterise the development of stentless valves as a collusion between industry and surgeons. It is not a myth that left ventricular hypertrophy is not good for the patient. That is why from the late 60's to the early 2000's I routinely emlarged the aortic root to try to get valves inserted that gave  single digit mean pressure drops. This goal is worthwhile. I dislike the term "patient-prosthesis mismatch" semantically but this does not alter the proper pathophysiologic goal needed to address left ventricular outflow obstruction.>   There are many good ideas that fail for economic reasons.> Bob> >      > > > -----Original Message-----> From: Dr. Roberto Battellini <battr at medizin.uni-leipzig.de>> To: OpenHeart-L at lists.hsforum.com> Sent: Mon, 21 Jan 2008 5:20 am> Subject: AW: [HSF] Access to AV groove area post bypass Bioprosthesis choice> > > > Yes, but which is the reason?> ay be Bob knows...> oberto> -----Ursprüngliche Nachricht-----> on: openheart-l-bounces at lists.hsforum.com> mailto:openheart-l-bounces at lists.hsforum.com] Im Auftrag von Hgrmd at aol.com> esendet: Montag, 21. Januar 2008 03:18> n: OpenHeart-L at lists.hsforum.com> etreff: Re: [HSF] Access to AV groove area post bypass Bioprosthesis choice> Prasanna,> On the basis of one study, I certainly don't plan to cut out the > ubvalvular apparatus with impunity. However, it's always good to keep an> pen mind. > well remember Tirone's lectures over 10 years ago about the virtues of > tentless aortic valves in LV mass regression. It's my understanding that> he > anufacture of the Toronto valve was recently discontinued.> > al> > **************Start the year off right. Easy ways to stay in shape. > ttp://body.aol.com/fitness/winter-exercise?NCID=aolcmp00300000002489> ______________________________________________> penHeart-L mailing list> Send postings to:> OpenHeart-L at lists.hsforum.com> To UNSUBSCRIBE, to CHANGE email address, or to view archives:> ttp://mmp.cjp.com/mailman/listinfo/openheart-l> All messages transmitted by the OpenHeart-L are subject to the policies and > isclaimers posted at:> ttp://www.hsforum.com/listdisclaim> ----------------------------------------> _______________________________________________> penHeart-L mailing list> Send postings to:> OpenHeart-L at lists.hsforum.com> To UNSUBSCRIBE, to CHANGE email address, or to view archives:> ttp://mmp.cjp.com/mailman/listinfo/openheart-l> All messages transmitted by the OpenHeart-L are subject to the policies and > isclaimers posted at:> ttp://www.hsforum.com/listdisclaim> ----------------------------------------> > > ________________________________________________________________________> More new features than ever. Check out the new AOL Mail ! - http://webmail.aol.com> _______________________________________________> OpenHeart-L mailing list> > Send postings to:> OpenHeart-L at lists.hsforum.com> > To UNSUBSCRIBE, to CHANGE email address, or to view archives:> http://mmp.cjp.com/mailman/listinfo/openheart-l> > All messages transmitted by the OpenHeart-L are subject to the policies and > disclaimers posted at:> http://www.hsforum.com/listdisclaim> -----------------------------------------
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