On- X valve is superior to outdated one like st jude and ATS

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nobog

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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)
The main difference that separates the SJM valve with all the other bi-leaflet valves is the "pivot guards". That my friends is why the SJM leaflets open fully, every pulse, at any mounting angle, at any pressure.

After the SJM valve came out everyone else said "we can do that to" and they sat down with their CAD machines and started with a tube, however just because you have 2 leaflets hung in an orifice doesn't make them function perfectly. So ... I will leave it at that - the catch 22 is I have proof but cannot disclose it - I prefer not to get sued, everyone has their favorite (Ford vs Chevy) so take your pick and be happy with your decision.
 

pellicle

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For those interested (knowing this is hard to find:

The ATS open pivot hinge system:
which you can see does not have a "tag" on the side of the leaflet but has a notch in it, which captures it on the lump you can see on the inner valve cylinder wall.

that "tag" on the side can fracture, I believe there are about two in the literature. Given the vast quantity of them in use I consider that safer than flying, which is safer than driving, which is safer than crossing the street looking at your phone (you know you've done that).

The St Jude

The On-X (I couldn't find videos) still seems to have a tag on the hinge that holds the leaflet in place and governs opening and closing.

1612733670745.png


they all look pretty similar to me, just variations on a theme. This is (probably) the current crop of themes.

1612733738422.png
 
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Unicusp

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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?".
Regarding laminar flow, this picture is from the SJM literature. Ahh, the battle between the Marketing Depts.....

1612795938423.png
 

Unicusp

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And here are the Pivot Guards mentioned earlier.....interesting design differences

1612796149531.png
 

drivetopless

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I think the point here is technology evolves to our benefit over time And aren’t we blessed to have more that 1 great valve option.

The skill and preference of the surgeon is also a factor. I would want a surgeon who is comfortable and skilled with SJM type to do that over an on-x install.

I have a 10 year old on-x, by the way. It was still relatively unheard of at the time. I interviewed three surgeons ... only 1 recommended the on-x at the time. He also was the only one with experience using it. So I went with him Hoping for positive news on anti-coagulation therapy in the future. At the time I was really concerned about long term use of warfarin....now, 10 years later...warfarin is no big deal and I definitely overthought it And worried unnecessarily.

I’m glad I Have an on-x. But I would have been okay with SJM In the hands of a skilled surgeon. both Are great options.
 

Protimenow

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'Hoping for positive news on anticoagulation therapy'?

I'm concerned that the 'positive news' would be a new medication that does, basically, what warfarin does - prevents clots from forming on the valve structures. Perhaps it'll somehow zap those little clots so they don't do any damage.

But, while the patent on such a miracle is in effect, I would expect this 'miracle' to cost a few hundred times what warfarin currently costs. ($8-10 a DAY for this new stuff, versus a dime or two a day for Warfarin).

Sure, there will be many people who will go this route - especially if insurance pays for most of the medication. We may all be tired of preparing our daily doses, watching what we eat and drink (to a point), and testing - but there will probably be a market for warfarin for quite a while.

There may not be 'positive' news for some time. An executive at the company that made the ProTime meter told me, a decade or more ago, that they were expecting a medication that would make testing unnecessary 'in the next five years.' We're still waiting.

If this stuff costs as much as the current anticoagulants for A-Fib, I'll continue waiting...
 

Mister_James

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I do believe this forum has On-X paid trolls that have to once in a while make claims of the superiority of On-x valves or lower INR requirement.
SJM is the current standard. Anything else is a come upper. Now maybe in a few years we will have a new standard but that is time and science not wishful publicity
 

Woodcutter

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I rather liked this picture . . .. found it attention getting! Don't know what specific valve it is but it shows the fundamental turbulent flow issue with bileaflet valves that plenty of researchers and engineers continue to work to minimize . . .ideally eliminate. This was in a publication discussing some work by the Cardiovascular Engineering Group at the ARTORG Center for Biomedical Engineering Research at the University of Bern (that's a mouthful!). They have quite a bit of their research readily accessible on their public site.

What I like about this is that it illustrates visually what a basic design objective is: minimize/eliminate that churning (turbulence) that takes place when you put something (i.e. leaflets of a mechanical valve) in the flowstream.

That turbulence is (probably) why we mechanical valvers get to take our drugs.
1612827431107.png
 

pellicle

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My ATS valve is awesome. That's what matters to me :). The FDA did a comparator study? Usually they approve a drug or device but make no statements on superiority. Valve choice is a personal matter.
missed this ... I've got an ATS too ... can't say its quiet, can't say it makes any significant difference to me. I was initially tilting (get it) towards On-X but my surgeon had a preference for ATS ... as its really WELL out of my domain of actual knowledge I just abdicated to him.
 

pellicle

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yes,
I rather liked this picture . . .. found it attention getting! Don't know what specific valve it is but it shows the fundamental turbulent flow issue with bileaflet valves that plenty of researchers and engineers continue to work to minimize . . .ideally eliminate. This was in a publication discussing some work by the Cardiovascular Engineering Group at the ARTORG Center for Biomedical Engineering Research at the University of Bern (that's a mouthful!). They have quite a bit of their research readily accessible on their public site.

What I like about this is that it illustrates visually what a basic design objective is: minimize/eliminate that churning (turbulence) that takes place when you put something (i.e. leaflets of a mechanical valve) in the flowstream.

That turbulence is (probably) why we mechanical valvers get to take our drugs.View attachment 887531
spot on ... its related to the pressures which happen at opening and closing; just like when you put your finger over a slowly running hose there is a brief high speed jet. This jet is not what the body was designed for (the native valve does not do this) and depending on intensity triggers thrombosis, something that I've mentioned here on this site a number of times in the past, but not for about the last 10 years because its "B52 Stratofortress" (so far overhead you can't even see it) for 99% of readers.

From this paper:

BILEAFLET VALVE The most commonly used bileaflet valve, the St. Jude Medical
(SJM) mechanical valve, has two semicircular leaflets that divide the area available
for forward flow into three regions: two lateral orifices and a central orifice. The
major part of the forward flow emerges from the two lateral orifices. A triple jet
pattern, shown in Figure 5, characterizes the forward flow (38). The lateral and
central orifice jets reach maximum velocities of 2.2 m/s and 2 m/s, respectively,
along the centerline plane 8 mm downstream of the valve at peak systole.


fig1.jpg


fig2.jpg


CAVITATION IN MECHANICAL HEART VALVES
Cavitation is the rapid formation and collapse of vapor-filled bubbles caused by a transient reduction in local pressure below the liquid vapor pressure (44).​
...​
Cavitation occurs on the inflow side of the mitral valve occluder surface at​
the instant when the occluder impacts the housing. The cavitation duration includes​
bubble incipience, development, and collapse. Its magnitude is on the order​
of a few hundred microseconds. The bubble collapse produces unique pressure​
characteristics, such as high-pressure oscillation, which is often used to detect​
cavitation (47, 48). Cavitation is more involved with local fluid dynamics and is​
therefore structure dependent. There are several factors that influence cavitation in​
MHVs:eek:ccluder closing velocity (49, 50), ventricular loading rate (51, 52), squeeze​
flow (53, 54), valve mounting (55), and occluder material properties (56, 57).​
...​
Recent evidence shows that the squeeze jets contribute more to cavitation than any other factor. During the formation of these jets, the fluid trapped between the occluder and housing is squeezed out of the gap during valve closure to form a high-speed jet. This jet mixes with fluid outside the​
gap and forms a strong shear layer in which vortices are so intense that pressure in the cores is low enough to lead to cavitation. These jets can be subdivided into squeeze jets and transvalvular jets (59), which can both cause jet vortex cavitation in the valve. This theory is supported by cavitation damage observed in the housing ring close to the leaflet contact site. Computational fluid dynamics has been utilized to show that the squeeze jet velocity can be as high as 14 m/s (53).​
(my bold)

So yes, to say there's a lot in this is somewhat of an understatement (and why I have zero time for partisan my valve vs your valve arguments).
 
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Keithl

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I am no DR or medical expert and just like anything else there are improvements made to designs. Do I think the St. Jude is outdated, no. Do I think the On-X is a bit better, yes. If I did not have a choice would I be fine with a St. Jude, yes. To me the subtle improvements we easy decision as well as the supposed lower INR target. That said my cardio and I both agree the 1.5-2 is too risky an difficult to maintain so I use 2-3 as my range with daily 81mg aspirin and I stay around 2.5-3.0 most of the time which statistics show is the safest (least events) range.
 

tom in MO

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Shiv is not the housewife indicated in Shiv's profile. Per another thread, he's actually a man without valve disease. He now claims his wife has the problem not Shiv.
 
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I am no DR or medical expert and just like anything else there are improvements made to designs. Do I think the St. Jude is outdated, no. Do I think the On-X is a bit better, yes. If I did not have a choice would I be fine with a St. Jude, yes. To me the subtle improvements we easy decision as well as the supposed lower INR target. That said my cardio and I both agree the 1.5-2 is too risky an difficult to maintain so I use 2-3 as my range with daily 81mg aspirin and I stay around 2.5-3.0 most of the time which statistics show is the safest (least events) range.
Hi

Regarding your diet do you eat everyday vitamin k? Or is it just like you eat vitamin k whenever but you just don’t go over a certain amount whenever you eat it
 

Keithl

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Messages
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Hi

Regarding your diet do you eat everyday vitamin k? Or is it just like you eat vitamin k whenever but you just don’t go over a certain amount whenever you eat it

I am a very predictable person, I eat the same thing most days of the week, Salad for dinner M-Th, some meat on Friday and Sat/Sun vary. My breakfast and lunch are also very predictable most of the time. My vitamin K intake is generally consistent. I also have found after all the reading I have been doing that I don't worry too much as my INR is fairly consistent and I am fine if I over shoot a bit rather than under shoot. Lately I have been hovering around 2.9-3.1 and just stick with my plan vs. to keep fidgeting with doses. Also whie most INR clinics will suggest you take your dose every night I take mine every morning, as my morning schedule is far more predictable than my night schedule. I can't think of a time I missed any morning pills, but on rare occasion forget evening meds.
 

cldlhd

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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?".
I'm no engineer and I don't have a mechanical valve but I thought that the reason for the platelet damage with a mechanical valve also has to do with them not closing gradually like a biological valve?
 
Joined
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Messages
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I am a very predictable person, I eat the same thing most days of the week, Salad for dinner M-Th, some meat on Friday and Sat/Sun vary. My breakfast and lunch are also very predictable most of the time. My vitamin K intake is generally consistent. I also have found after all the reading I have been doing that I don't worry too much as my INR is fairly consistent and I am fine if I over shoot a bit rather than under shoot. Lately I have been hovering around 2.9-3.1 and just stick with my plan vs. to keep fidgeting with doses. Also whie most INR clinics will suggest you take your dose every night I take mine every morning, as my morning schedule is far more predictable than my night schedule. I can't think of a time I missed any morning pills, but on rare occasion forget evening meds.
I can’t see myself eating salad for supper lol but we can eat chicken and things for supper like maybe one night il have chicken another night maybe a cheese sandwich and fast food do we need to cut that out. Sorry I’m fairly new to this I’m 4 weeks into my recovery so it’s a bit hard letting go some of the things
 
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