On- X valve is superior to outdated one like st jude and ATS

On- X is way ahead in technology
As it is made of pure carbon without silica..so it cause less thrombosis than the older technology from st jude and ATS specially.

M

Shiv said:

On- X is way ahead in technology
As it is made of pure carbon without silica..so it cause less thrombosis than the older technology from st jude and ATS specially.

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My surgeon says on- x is today what st jude was in 1990s. Leaps ahead..

Also, it has an improved Design, times are always changing, and for those that do not want to go to a hospital for another pre-planned surgery like me , it was the best option, TAVs are all possibilities, but not certainty depends on what is the environment around valve #1 and tissues around it, and size, a valve inside a valve, has limitations how many things you can put inside of it. This is "my" perspective, other people have their perspective, after all we do not live in Communist China ruled by CCP...

On- X is way ahead in technology
As it is made of pure carbon without silica..so it cause less thrombosis than the older technology from st jude and ATS specially.


OK.... time to set the record straight: Every bi-leaflet valve that was invented after the SJM was made to get around the SJM patent - so in the end its the same thing in a different flavor. That doesn't make it better. Onx touts their carbon, but we know Delrin works, titanium works, nitinol works - amongst others - so where does leave us? All current mechanical valves (and a few trusted old ones) have a reasonable in-vivo track record - so there it is. There is one feature of the SJM valve that the astute will notice from 12" away, I'll see if anyone can figure that out - but that's the reason for its consistent leaflet function and performance. To say "leaps ahead" is just plain fiction. What is not fiction is Onx's marketing - and you and your surgeon bought into it.

Thanks Nobog for your reply. I'm just looking for pure facts and no BS. Please confirm that the On-X and SJM are made of the same carbon. To your challenge question, I would say that the SJM has a larger EOA than the On-X when comparing same sizes. My surgeon also stated that the SJM has superior hemodynamics and is quicker and easier to install precisely meaning less time on the table and machines.
Regarding patents, wouldn't the SJM patent be expired by now or has it been renewed? Please continue to share great objective information. Thanks!

Hey Uni

you will note that I've pretty much said this many times over the years and in many posts.

Unicusp said:

. Please confirm that the On-X and SJM are made of the same carbon.

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they both use pyrolytic carbon ... simply read their product literature. However for your convenience:

https://www.sciencedirect.com/topics/medicine-and-dentistry/pyrolytic-carbon

Best Wishes

PS:
https://pubmed.ncbi.nlm.nih.gov/7130212/

Lastly to repost what I have posted frequently in the past:

https://en.wikipedia.org/wiki/Pyrolytic_carbon

The carbon is different - which is better? Of course Onx claims their carbon is nothing short of this miracle substance but as I mentioned, many materials, with many different surface characteristics "work". If I remember correctly I believe the Onx is solid carbon, whereas the SJM has a graphite core (yup, just like a pencil) and then carbon coated. EOA's are about the same.

Everyone tends to look at the flow numbers, EOA or pressure drop, so that makes the cuff super thin - so that give the surgeon this little tiny strip of dacron as your only "seal". Paravalvular leakage is a significant issue and a 1mm "hole" can pass a significant amount of fluid (blood) going the wrong way at any pressure.

Thankfully I am not in the need of a heart valve (nor do I have one now) but if I was on the list and it was mechanical I would want:

1. valve history / reputation
2. performance (flow and durability)
3. easy to implant
4. a nice big fluffy cuff (I would sacrifice EOA for this except for very small size valves)

I would not worry about carbon type or INR claims.

The patents have long expired, nobody wants to make a copy as that would say we are just coping the best. Although these are all bi-leaflet valves, the differences are mainly in the leaflet hinge area - and of course the one major difference I alluded to before (which is what sets the SJM apart from all the rest).

nobog said:

which is what sets the SJM apart from all the rest

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being unfamiliar with them in the flesh (so to speak) is it the opening angle? (just no or bingo, don't tell, I'm keen to guess or research this)

PS: I cheated and looked at a few online. My second guess is the amount that it extends beyond the stitching ring. (pannus guard?)

Well .... no, opening angles are similar for all bi-leaflet valves. 2nd guess, are you referring to inflow (proximal) or outflow (distal) ?

nobog said:

Well .... no, opening angles are similar for all bi-leaflet valves. 2nd guess, are you referring to inflow (proximal) or outflow (distal) ?

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Looks like the SJM is intentionally at 85% opening vs the On-X at 90%. Why did SJM choose 85%?
The SJM has an overall lower implant height. To your other comment, would you then choose the bigger Flex cuff for a better seal?

pellicle said:

Hey Uni

you will note that I've pretty much said this many times over the years and in many posts.



they both use pyrolytic carbon ... simply read their product literature. However for your convenience:

https://www.sciencedirect.com/topics/medicine-and-dentistry/pyrolytic-carbon

Bileaflet valves have two semicircular pyrolytic carbon discs attached to the valve ring by two small midline hinges. St. Jude Medical, CarboMedics, Advancing the Standard ATS bileaflet and the On-X are the prototypes of this group​

Best Wishes

PS:
https://pubmed.ncbi.nlm.nih.gov/7130212/

To assess abrasive wear of mechanical valve prostheses containing pyrolytic carbon components... All carbon occluders had undetectable wear. ... This study suggests that clinically important abrasive wear will not be a late complication of cardiac valve replacement with pyrolytic carbon prostheses.​

Lastly to repost what I have posted frequently in the past:

https://en.wikipedia.org/wiki/Pyrolytic_carbon

Pyrolytic carbon is man-made and is not thought to be found in nature ...It is used nonreinforced for missile nose cones and ablative (boiloff-cooled) rocket motors. Prosthetic heart valves. Radial head prosthesis.​

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Pellicle - you are definitely the Data King! Thanks!

Unicusp said:

Pellicle - you are definitely the Data King!

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Oops

nobog said:

Well .... no, opening angles are similar for all bi-leaflet valves. 2nd guess, are you referring to inflow (proximal) or outflow (distal) ?

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It appears to be a bit longer both ends.
A picture from my blog (couldn't quickly find it in their literature)

Unicusp said:

Pellicle - you are definitely the Data King! Thanks!

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No. He is god.

jlcsn2015 said:

Also, it has an improved Design, times are always changing, and for those that do not want to go to a hospital for another pre-planned surgery like me , it was the best option, TAVs are all possibilities, but not certainty depends on what is the environment around valve #1 and tissues around it, and size, a valve inside a valve, has limitations how many things you can put inside of it. This is "my" perspective, other people have their perspective, after all we do not live in Communist China ruled by CCP...

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Yes agree..On-x is better than other options. US FDA agree with it..doesn't matter if some people don't agree here..they are not God..yes its democracy no hitlership.

I do not have any opinion on On-X vs SJM. (My mitral valve is an SJM.) My technical experience is with fluid mechanics/hydraulics and as with most engineers have dealt with a myriad of materials. I have no concern with the silica content and do not believe it an appreciable factor in mechanical valve induced thrombosis. The research that I have read has found no differences from about a 3% to a 13% silica content.

Where I do agree with the On-X literature is with regards to laminar flow. This is very important as it is generally thought that turbulent flow is the root cause of platelet, cell, etc. damage that leads to the formation of clots. Interestingly, even after decades of research, the fundamental root cause of mechanical valve thrombosis is not unequivocally nailed down. The body is rather complicated! However, turbulent flow - where molecules/cells/components are bouncing around randomly and with a lot of energy - is generally thought to be the cause; rather than the specific surface conditions on benign materials like pyrolitic carbon.

I am intentionally trying to not be technical. Laminar flow is smooth . . . like a calm quiet stream. Turbulent flow is that stream churning around and getting frothy like when it hits a rock. That is the rub with mechanical valves. Currently, they all stick some structure in that stream. Very difficult to avoid turbulence when you stick something in the stream . . ..and then have it move around every heartbeat! Biologic valves do not have that structure in the middle of the stream.

There is (still) current work taking place to reduce the turbulence in mechanical heart valves so it is possible there are technical improvements yet to come even in this rather proven technology.

I will share a random memory that popped into my mind when I saw the On-X literature showing a surface scan of the "pure" vs "silica" carbons. The "pure" picture was smoother which implies it is more conducive to laminar flow. But physics is not always simple. My recollection was a fluid mechanics professor asking the class: , " so, if we are all in agreement that smoother is better, why do golf balls have dimples?".

Anyway, except marketing, the recent conclusions are:

"The three bileaflet mechanical aortic prostheses
(On-X, Bicarbon, and ATS) provide satisfactory early hemodynamics,
which are comparable between the three valve types and among
different valve sizes.".
Early Hemodynamic Profile after Aortic Valve Replacement — A Comparison between Three Mechanical Valves

https://cdn.publisher.gn1.link/bjcvs.org/pdf/0102-7638-rbccv-2020-0273.pdf

But then whoever reads your echos etc will write up that your valve is tri-leaflet and has calcified. Even though you have an On-x valve now (made up of inert carbon which cannot calcify) and that replaced your old bicuspid valve in the first place....don't get me started....

Shiv said:

Yes agree..On-x is better than other options. US FDA agree with it..doesn't matter if some people don't agree here..they are not God..yes its democracy no hitlership.

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Prove it.