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Nano Nano - The Valve of the Future?

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ElectLive

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Jun 26, 2011
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Atlanta, GA
I'm going to venture a guess that IF I were to conduct a poll, and ask everyone here if they were granted 3 wishes related to the future of heart valves - what they would be, that the final tally might include one or more of the following:

1. Mechanical valve that requires no ACT
2. Tissue valve that lasts forever
3. Catheter (TAVI/TAVR) installed version of either of the above

Well, what if one day, many years from now, you could actually have all three options, but distilled into a single amazing "Valve of the Future"...

My surgeon introduced me to this topic during our first pre-surgery meeting. He had spent 40 minutes or so addressing the nuts and bolts of my case, and had been rattling off inumerable risk/complication rates to the nearest decimal point like only a surgeon can. Then, all of sudden, he threw in a quick little anecdote about what he thought just might change everything for valve patients in the future. He termed it a "hybrid mechanical" valve, inserted by catheter, with a "micro mesh nano technology" of sorts that native tissue would overgrow and engage, including even the leaflets, thus eliminating the need for ACT. Now, I was a little busy at the time planning for my surgery, and quite honestly wasn't on the edge of my seat for a solution 20 - 25 years down the road. So, I never questioned him further about it and just assumed it was likely only in the concept and research stage.

Well, imagine my surprise when I recently read that this mythical valve not only exists firmly in concept, but has also gone through limited animal testing, and is even being mentioned in industry wide (ACC/AHA) literature. In the newly available ACC/AHA "Expert Consensus Document on Transcatheter Aortic Valve Replacement", this formerly nameless (at least to me) "Valve of the Future" is identified and named as a potential next-generation TAVR device by the experts of the profession:

"The PercValve (Advanced Bioprosthetic Surfaces [Palmaz Scientific]) uses nanotechnology in its elastic nitinol frame and leaflets. These leaflets are designed to allow for the growth of endothelial cells, essentially converting it to a tissue valve. Initial animal studies have shown complete endothelialization of the e-nitinol leaflets within 10 days and may eliminate the need for anticoagulation."

Now, if only there were a nano-scientist or nano-engineer with a faulty valve among us who can expand upon this? I certainly am neither, and maybe that's a good thing, because at least that allows me to dream big and think that maybe this is really the idea that will change everything, as my surgeon had said.

Now, assuming it does everything it says it will do, still time for some skepticism. I'm sure there may be reasons why this idea may not translate completely over to the human body. The name behind this PercValve also is not overtly impressive. In other words, if it were the St. Jude PercValve or the Edwards PercValve, it sure would sound a lot more promising and realistic, wouldn't it? Even if were, though, it still obviously would be a long long process (human testing, clinical trials, FDA approval, etc) so a 20 - 25 year estimate (my surgeon's guess) seems pretty fair. Hopefully, though, during that time, the still imperfect world of transcathether valve replacement will also be evolving, and a host of other issues getting worked out (lower profile devices, ability to reposition or retrieve, among others).

Anyway, the world just doesn't change overnight, so all things considered, I still think it's very promising to hear of valve concepts such as this that just might change everything, someday, for valve patients.
 

catwoman

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near Fort Worth TX
I'm not an AVer. My MV was replaced because it had become myxomatous. I would like for medical experts to find a prevention for that so that NO surgery would be required.
 

Sarah_Louise

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Sep 26, 2010
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604
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UK
Sounds good!
My friend was waiting to go in for a new procedure to replace her pulmonary valve, she tried pericutanrously but it wouldn't stay in place, so they where going to try and do a hybrid method of some sort, don't no the ins and outs of it and can't ask as she's no longer with us but would be amazing!
Love Sarah xxxx
 

Protimenow

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California
I don't think that the name of the company making the valve matters a whole lot -- some smaller companies may be doing the most innovative research. In fact, these smaller companies - possibly offshoots from medical research labs or schools - may be swallowed up by the St. Jude and other larger name companies once the valve has enough demonstrated success.

Although FDA approval CAN take a really long time, if the device has proven success in animal studies, and with human volunteers (once that phase of testing is approved), the approval can possibly be put onto a faster track for approval - especially considering what this new type of valve will be replacing (animal valves that often don't last more than 7-20 years or mechanical valves that require lifelong anticoagulation). Although I have a personal concern about this type of valve (not being a doctor or biotechnology expert), if this thing can be proven, without negative secondary effects over time, it may be fewer than 25 years before such a valve becomes available.
 

ElectLive

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Atlanta, GA
Well, I had much more mystery than fact when I started this thread last year, so wanted to add a little more info I've found here: http://www.nature.com/pr/journal/v63/n5/full/pr2008108a.html.

Thin film NiTi transcatheter heart valves.

Thin film nitinol has favorable biologic properties as well as elastic properties, which make it an ideal material for use in transcatheter heart valves. Because nitinol also has shape memory, entire heart valves (the leaflets and support structure) can be made entirely from nitinol such that they can be compressed into a catheter and delivered into the heart without using cardiopulmonary bypass and without an invasive surgical procedure.

A thin film nitinol heart valve could represent the ideal hybrid valve: it could have the biologic compatibility and nonthrombogenicity of tissue valves and the longevity of a mechanical valve (nitinol has very impressive fatigue properties). Although tissue valves are now being placed percutaneously in both the aortic and pulmonary positions, none of the currently available transcatheter valves have leaflets with shape memory, none have the longevity of a mechanical valve and all of the valves currently in trial require sheaths >18–19 Fr. Transcatheter valves which incorporate thin film nitinol would certainly have a lower profile (less than even 5 Fr), would have shape memory leaflets and would likely have very favorable fatigue properties (if designed correctly).

A team led by Julio Palmaz, M.D., Steven Bailey, M.D., and Chris Banos at ABPS has designed and has begun animal testing on a semilunar thin film NiTi heart valve. The ABPS valve incorporates leaflets made from 10 μm membranes of thin film nitinol, which is made to be very flexible by incorporation of multiple regularly spaced small fenestrations. These membranes termed “eNitinol” are sufficiently flexible to be used as leaflets in a semilunar valve design. The leaflets are designed to serve has very flexible scaffoldings for the growth of endothelial cells—this essentially converts this entirely metal valve into a tissue valve through a normal biologic response. The ABPS “eNitinol membrane PercValve” has an elegantly designed supporting scaffolding which enables it to be self expandable. The ABPS heart valve can collapse into a 10 Fr sheath, and a similar valve designed for use in the venous system can be delivered through a 4.8 Fr sheath.

I'm sure I'm well past my 1,000 words by now, but here finally is also an actual picture:



Now, one disclaimer, this article I quoted is 5 years old, probably not a good sign that there is little, if any, current news. But as I mentioned earlier, this is very likely not the valve for us, but for the next generation instead, and particularly for those with young children or grandchildren, it could certainly offer great hope...
 

Agian

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Jun 10, 2013
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Adelaide, South Australia
I don't know what you scientific types make of this. From what I understand this one is retrieveable, which seems to imply that if it wears out you can pull it out and replace it with another one (I could be wrong). Would this mean that the valve-in-valve developments become a non-issue?

Imagine that! They open you up, fix your aorta and give you a tissue valve. Ten years later they put one of these in through your groin and do a valve-in-valve procedure. The third procedure would involve going in through the groin, taking this out and sliding a newer model it. Inconvenient? Sure. It means a few visits to the cath lab over the decades. Tell me it is so.

How far away is this?

If I lived in the UK I would try and establish comms with these guys. :redface2:

I might ring them up myself.

http://www.ibme.ucl.ac.uk/transcatheter-aortic-valve-implantation-tavi/
 
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