The Great Valve Debate

[RCB]

Let not sqabble over who has the best research, let debate the future of valve choices. I'm not going to set up a poll, because that would be just numbers, not discussion which is what we do here.

What do you think the direction of valves will take to solve the problem of people with valve problems: 1. Mech. valves like On-X and others will be found not to need warfarin. 2. Tissue valves will be made that will not ware out. 3. Tissue engineered valves will become a reality.

If you think about it, it is not an easy answer but one all of us would like to see happen yesterday. Your thoughts please.

 

[geebee]

I think someone will develop a tissue valve that will not wear out. People seem to be getting longer and longer lifespans out of tissue valves. I hope this is where the research is focused. I would love for folks to know they can avoid coumadin AND re-surgery.

 

[tobagotwo]

Valve Futures

Valve Futures

I honestly think it's a race between all three of those choices and some other dark horses out there. There is really big money out there for whoever finally gets it right. The beauty is that we don't care which company wins, as long as somebody does...

- I strongly suspect the non-warfarin (apologies to Al) mechanical is closest to becoming reality. If it doesn't quite make it this time, someone will come up with an even slicker, denser pyrolitic carbon that mimics Teflon's antistick properties with carbon's integrity.

- A new plastic compound, perhaps from the polyurethane family, may yet show up that has flexibility, longevity, and non-warfarin capabilities.

- My all-time favorite would be the Chia valve, where your own tissue is grown on a framework. This would be your own valve. If they can't make them to last in the high-pressure aortic position, then they should make them for pulmonary use in Ross Procedures, until a better all-around solution is found.

- I think tissue valve usable lifespans will max out at 25-30 years, and wind up a blind alley for permanency. For now, they can be great for those for whom they are appropriate. They may continue to be used in people over 60-65, due to availability and nonreactivity to other prescriptions older folks need to take, reasons why they are popular for older folks now.

- Percutaneous valves are on the move. I still haven't found out what they're made of, but there are several companies out there making them and into clinical trials, including Edwards. I assume that ACT is involved, as it seems unlikely tissue could be mounted on an expandable stent reliably and without harming its integrity.
These valves will continue to popularize. Insurance companies will push hard for it, as implantation costs are lower (or will be - currently these valves are incredibly expensive). Interventional cardiologists will push hard for it, because it will be a new, lucrative procedure for them. Standard cardiologists will push for it, because it is expected to be a safer procedure, particularly for the fragile elderly.
Right now, percutaneously-implanted valves are not nearly as robust as more conventionally implanted valves. However, these companies will be competing with each other to improve these products to the extent that they can enter and compete in the mainstream market. It is likely that they will eventually succeed. This is somewhat disturbing, because if it becomes cheap enough, it may well be made the standard of care, even if it is only marginally satisfactory.


Best wishes,

 

[Les]

My all-time favorite would be the Chia valve, where your own tissue is grown on a framework.

This would be my hope for the future.

 

[Randy & Robyn]

I strongly believe the final and perfect solution will inevitably be one that allows a natural valve. Progress in tissue engineering has not been as rapid and revolutionary as they had hoped. I am sure everyone remembers the incredible predictions they were making after they implanted a framework of polyester fabric populated with human cartilage cells onto the back of a mouse back in 1995. But there have been slow and steady advancements. In the not-too-distant future, perhaps ten or twenty years, I can foresee the growth of replacement tissue and entire organs becoming very commonplace.

I also predict that before this solution is realized, we will have at least another one or two new generations of evolving mechanical and tissue valves and at least a few hundred more heated debates concerning them on this forum.

Randy

 

[tobagotwo]

They actually have been able to make the chia valves for over a decade. They were arterial wall cells grown under pumped pressure on a skeleton of denucleated pig cartiledge. They seemed quite successful when implanted in lambs, and offered great hope, because they actually grew with the lambs' hearts.

Because they could grow with their host, they were first tried on children. Unfortunately, they were far less succesful in humans. The difficulty may have been partly in the mode of manufacture, the structure of the human valve, or the specialization of the human arterial wall cells. Regardless, they were a sad failure, and as i recall, the company was enjoined from manufacturing them for several years. It is likely they will have that ban lifted later this year.

Let's see if they've done any noteworthy rethinking while they were in "time out" punishment.

Best wishes,

 

[PapaHappyStar]

In the out there category -- I think one could see molecular motor based valve repairs, to rejuvenate damaged valves cell-by-cell. I think this would be the ultimate: a truly 'minimally invasive' valve repair -- hopefully in less than 50 years.

One would think we would be close to achieving nearly non thrombogenic mechanical valves -- but this wont be due to materials, they will need some changes in design. Hard, smooth valves create turbulent flow around the edges and the hinge area that damage blood cells and release chemicals in cells that promote formation of blood clots. Maybe better computer simulation is needed

The native tissue valve with the pig tissue framework is probably going to be the longest lasting as long as the cells remain viable, the surface dosent calcify and the frame remains supple -- this may be achievable as well.

Looks pretty good -- I think we may be a bit further away from having a percutaneous ( catheter based ) aortic valve replacement, though the pulmonary valve is possible even now.

 

[ar bee]

another turn

another turn

what if science develops an even better, ie differentiated understanding of blood clotting mechanism and the thing becomes manageable with a much simpler approach?

 

[tommy]

chia valves

What a hoot! Is this named after the famous chia pet that shows up on TV ads every Christmas?

I hope that both tissue valves and mechancial valves continue to improve. Neither will likely ever be perfect. People will want a choice. If the costs become hugely divergent, then the insurance companies and HMO's may only want to pay on the less expensive one.

 

[tobagotwo]

I have to come clean on this one, Tom. The name is from the Chia Pets that show up on low-budget TV ads every so often.

However, that's not the proper name for them. I started calling them that after I read articles about them some years ago. I have to admit, Ive been secretly hoping the name would stick, because it seemed so apt.

The product was from CryoLife, and was part of their Synergraft line.

It's possible the people who have worked to develop them might be outraged by the nickname, but I hope not...

Best wishes,

 

[tommy]

Bob,

It's borderline brilliant to come up with a nickname that instantly communicates the thought. I have this "visual" of a heart valve growing little green sprouts. I'm laughing my tail off. Now Chia hair replacements...................?

PS.....so far "valvathoner" has not caught on in the marathoning community.