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

Tue Jan 22 16:43:17 EST 2008

Dear Ani,
I am in a hotel where they charge by the second for internet access. There is no way I can do justice to your questions.
Also having read your posting I am obliged to say "You will have to be more specific than that" (The quotes are because that sentence is the punchline to an old joke).
Recognise that literature articles by no means drive what happens in the field. The feed back from the field , from the beginning, was clear: "this thing is too difficult for me, my clamp times are too long, I know how to do a stented valve,
my patients are getting through surgery , why should I change?" The use of stentless valves at the height of the early favourable reports was never more than a small fraction of total bioprosthetic use. A few years after intorduction the numbers peaked, flattened and began to fall. I have added a couple of comments to your text.

-----Original Message-----
From: Ani Anyanwu <anianyanwu at hotmail.com>
To: openheart-l at lists.hsforum.com
Sent: Mon, 21 Jan 2008 11:09 pm
Subject: RE: [HSF] Access to AV groove area post bypass Bioprosthesis choice(stentless valves)

Dr Frater

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

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

) Studies from Toronto (where many of the patient-prosthesis and stentless 
roponents reside) did not show elimination of "patient prosthetic mismatch" by 
ither EOA or direct measurement of gradients in patients receiving stentless 
alves I believe I know which author's papers you are referring to. Try reading them in sequence. 
As "evidence" they are poor.

) Most major proponents of the stentless valve - most notably Dr David - now do 
ot recommend their routine use, even in the setting of a small annulus 
r David will tell you he has alternatives and I believe he has recognised that 

his original condemnation of aortic root enlargement was wrong, but don't take my second hand
quote; ask him directly.  There was also a belief that doing away with stents would improve wear 
We can discuss why this may have been wrong. Note also the absence of an anticalcificarion Rx in
most of the first models

) 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 
dwards perimount as a control and at that very time the essence of using a 
tenless valve was to avoid placing a perimount or similar (the standard at the 
ime). So at least the stentless valve - if the hypotheses were correct - should 
ave been superior to the contaprenous stented valves. Additionally, stentless 
alve was the chosen mode of AV replacement of a number of surgeons active in 
he 1970s and 1980s such as Barratt-Boyes, Ross and Yacoub but their data did 
ot show convincing (patient survival) benefit compared to then first or second 
eneration porcine valves.I realise from this that you are including homografts under
"stentless valves". They are very different physically and biologically and probably 
should not bepart of this debate.

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

) Being porcine, the results of these prosthesis may not necessarily mimic that 
f a (stented) pericardial valve.
o argument with "may" being the operative word. 
 am sure you will provide more insight into the historical evolution of these 
alves and correct any misinformation.

hanks

ni

> To: OpenHeart-L at lists.hsforum.com> Subject: Re: [HSF] Access to AV groove area 
ost bypass Bioprosthesis choice(stentless valves)> Date: Mon, 21 Jan 2008 
3:12:55 -0500> From: rwmfglycar at aol.com> CC: > > By doing away with rings and 
truts a hemodynamic improvement was achieved in small aortic roots. This 
ithout doubt resulted in less resistance across the aortic orifice than 
rovided by the contemporaneously available stented valves and this in turn 
roduced greater regression of LV hypertrophy. Since left ventricular 
ypertrophy is a risk factor for death this seemed like a good idea.> The 
ownside of the several stentless valves on the market was that many surgeons 
ound them difficult to insert. This last issue never went away and there were 
any surgeons who found them too difficult to use and more or less said there is 
ome regression of hypertrophy with stented valves and that is good enough for 
e. In the meantime the design of stented valves improved so that the difference 
n hemodynamic performance became substantially less. Sales of the stentless 
alves decreased annually until it became economically impossible to maintain 
he plant needed to continue building them.>    It is unfair to characterise the 
evelopment of stentless valves as a collusion between industry and surgeons. It 
s not a myth that left ventricular hypertrophy is not good for the patient. 
hat is why from the late 60's to the early 2000's I routinely emlarged the 
ortic root to try to get valves inserted that gave  single digit mean pressure 
rops. This goal is worthwhile. I dislike the term "patient-prosthesis mismatch" 
emantically but this does not alter the proper pathophysiologic goal needed to 
ddress left ventricular outflow obstruction.>   There are many good ideas that 
ail for economic reasons.> Bob> >      > > > -----Original Message-----> From: 
r. Roberto Battellini <battr at medizin.uni-leipzig.de>> To: OpenHeart-L at lists.hsforum.com> 
ent: Mon, 21 Jan 2008 5:20 am> Subject: AW: [HSF] Access to AV groove area post 
ypass Bioprosthesis choice> > > > Yes, but which is the reason?> ay be Bob 
nows...> oberto> -----Ursprüngliche Nachricht-----> on: openheart-l-bounces at lists.hsforum.com> 
ailto:openheart-l-bounces at lists.hsforum.com] Im Auftrag von Hgrmd at aol.com> 
sendet: Montag, 21. Januar 2008 03:18> n: OpenHeart-L at lists.hsforum.com> 
treff: Re: [HSF] Access to AV groove area post bypass Bioprosthesis choice> 
rasanna,> On the basis of one study, I certainly don't plan to cut out the > 
bvalvular apparatus with impunity. However, it's always good to keep an> pen 
ind. > well remember Tirone's lectures over 10 years ago about the virtues of > 
entless aortic valves in LV mass regression. It's my understanding that> he > 
nufacture of the Toronto valve was recently discontinued.> > al> > 
*************Start the year off right. Easy ways to stay in shape. > 
tp://body.aol.com/fitness/winter-exercise?NCID=aolcmp00300000002489> 
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