Which Mechanical Valve produces the lowest number of bloodclots?

Help Support ValveReplacement.org:

tommyboy14

Member
Joined
Mar 17, 2014
Messages
20
Location
London, United Kingdom
Hello,
I was recently diagnosed with BAV, am 33 and am stil thinking about the choice of Ross versus mechanical valve.

Are the different mechanical valve's (St Jude's Regents, ATS or OnX) diffferent i ntheir tendency to produce bloodclots given the same INR?

I.e. are there any studies who have actually evaluated this?
I thought that given that the OnX valve has now been approved for use with an INR of 1.5-2 in Europe, it must generate less bloodclots (thrombosis) then the others.
Is that assumption correct?
[Why else would be they be able to market this with lower INR?]


Any feedback on this would be very useful.

thank you

tommyboy
 

clay_from_nj

Well-known member
Joined
Oct 23, 2012
Messages
397
Location
Fort Lupton, Colorado, USA
Marketing hype, mostly. Just trying to stay within such a narrow range is probably very difficult. Realistically, you should take the advice of your medical professionals (surgeon, cardiologist, pharmacist).

They're not the first:
The ATS valve has excellent haemodynamic characteristics and a very low thromboembolic rate, probably related to the convex self-washing hinge mechanism. Consequently, we have reduced anticoagulant levels to INR (international normalised ratio) 1.5 to 2.0 for aortic valve patients in sinus rhythm. - Eur J Cardiothorac Surg. 1996;10(8):660-5, Valve replacement with the ATS open pivot bileaflet prosthesis.
 
Last edited:

pellicle

Professional Dingbat
Joined
Nov 4, 2012
Messages
6,162
Location
Queensland, OzTrayLeeYa
I.e. are there any studies who have actually evaluated this?
to my knowledge there are no studies which have done examination of the question you ask, however it can be inferred that all of the modern pyrolytic carbon valves are less clot producing than the older models. That said there are likely very small differences between them. I have found articles such as this:
http://www.valvereplacement.org/forums/showthread.php?42674-ON-X-Valve&p=551240#post551240

Google scholar is your best bet for digging out this sort of thing, however my advice to you is this:

If you choose a mechanical valve then stay within the theraputic range as guided by your surgeon. There is a new view in the European community to target an INR as your median (2.6) and try to stay close to that. Naturally like a planet orbiting a sun you will not be on it perfectly but orbit around it. The goal however is to be more like a planet than a comet (coming in tight but then flinging far out again).

For instance a plot of my INR from 2013 looks like this:


My mean was 2.5, Standard Deviation 0.3 which means that in by far the majority of times that I was no more than 2.2 or 2.8 (with the actual data as you see).

I measure personally weekly (with measurements more frequently if I go out of range for some reason). I had a surgery (sigh) in the beginning of 2013 which upset my "apple cart" a bit.

It is a fools erand to attempt to hover on a ultra low INR because there will be times when you drop out to very low levels and be at risk of a clot. Clots cause strokes and while you may emerge undamaged, you may not.

There is no harm in being in a range such as I've mentioned above and compared to old timer valves with an INR range much higher we're better off. Dick survived as did some others (I know of another person who has been on warfarin for over 50 years with no incidents - clearly he started younger too ;-)
 

epstns

Premium User
Joined
Dec 26, 2002
Messages
5,075
Location
Chicago area
Pellicle - Where were you when I was trying to stabilize my INR during the 3 months post-surgery? Although I have a tissue valve, I did take warfarin for 3 months after surgery as a standard procedure at the hospital I used. It took most of those 3 months to stabilize my INR, driving my visiting nurse crazy and making me feel like a pincushion.

Your analysis makes immediate sense to me, and I thank you for posting where others can see it. Since we lost our previous warfarin guru (Ross), we haven't had anyone here who took such an analytical approach to warfarin management. People can learn a lot from you.
 

pellicle

Professional Dingbat
Joined
Nov 4, 2012
Messages
6,162
Location
Queensland, OzTrayLeeYa
Steve

thanks for the kind words

Pellicle - Where were you when I was trying to stabilize my INR during the 3 months post-surgery?... It took most of those 3 months to stabilize my INR, driving my visiting nurse crazy and making me feel like a pincushion.
Actually I've noticed that there is some sort of cyclic metabolic thing happening, and if you're not armed with enough data you miss it. I guess I got this view from my signal processing daze in electronics. Basic waveform analysis requires you have enough sample points to see the underlying frequency properly



Seeing other harmnoics requires more sampling. Of course with getting vein puncture samples noone wants to test every other day (god knows I hate needles).

Right now I find weekly sampling and a 3 week moving average trendline is a very helpful indicator to know if I should steer up or steer down or "steady as she goes" with dose.

Perhaps only an IT / Electronics sort of Engineer with a biochem degree as a starter would love this .. :-D
 

ElectLive

Well-known member
Joined
Jun 26, 2011
Messages
631
Location
Atlanta, GA
I thought that given that the OnX valve has now been approved for use with an INR of 1.5-2 in Europe, it must generate less bloodclots (thrombosis) then the others.
Is that assumption correct?
[Why else would be they be able to market this with lower INR?]
The On-X PROACT trial has generated a lot of valuable data, but internally focused only. There is no sound reason to automatically assume it is better than the others based on PROACT alone. Could it be? Sure. Has it been proven? No. Beyond some of the slightly "hidden" aspects of PROACT (such as the actual impact of reduced INR on TIA's and stroke) that are not all publicized, the trial itself has been conducted under absolutely best case circumstances: very tight clinical control and review, above average home INR monitoring frequency, etc. Not only have other valve manufacturers not done a comparable trial at INR 1.5-2.0...I'm pretty sure such a comprehensive and thorough trial has never been undertaken at any INR for any valve manufacturer.

I started a thread not too long ago on the marketing aspect of On-X's European approval milestone that might also be of interest to you: http://www.valvereplacement.org/forums/showthread.php?42468-On-X-CE-mark-and-%28unfortunately%29-1-5. I was very opinionated about the ethics of their new marketing campaign, so as a potential customer right now, I'd encourage you to ignore that part :wink2: and focus instead on the numbers. There is a link (to another forum thread) embedded in one of my posts there that will lead to two very thorough data packages that On-X produced at different stages of the trial. It covers patient make-up, protocol, event summaries, relationship of event to INR levels, etc...very informative.

Marketing is one thing...sound data often quite another. I think it's very fair to say that On-X has proven they have a very sound and safe valve that will allow some amount of flexibility to reduce target INRs as a means to avoid bleeding events, beyond what is traditionally done. I absolutely do not believe they have proven that someone targeting INR 1.5-2.0 will be no more susceptible (compared to self or other) to TIA's and stroke, though.
 

Lynlw

VR.org Supporter
Joined
Jul 15, 2005
Messages
6,541
Location
NJ
Hello,
I was recently diagnosed with BAV, am 33 and am stil thinking about the choice of Ross versus mechanical valve.

Are the different mechanical valve's (St Jude's Regents, ATS or OnX) diffferent i ntheir tendency to produce bloodclots given the same INR?

I.e. are there any studies who have actually evaluated this?
I thought that given that the OnX valve has now been approved for use with an INR of 1.5-2 in Europe, it must generate less bloodclots (thrombosis) then the others.
Is that assumption correct?
[Why else would be they be able to market this with lower INR?]


Any feedback on this would be very useful.

thank you

tommyboy


I personally believe the most used mech valves today, are pretty close, as far as the chances of clots, so need anticoagulation that increases your chance of bleeds, or if one was clearly better everyone would use that. so far they don't. Luckily most people are very happy with THEIR valve and believe theirs is the best mech or best tissue and for them it is.

I think the only way to get a small idea of "which" valve clots the least, and it of course wont be exact, is read several studies on the individual valves, but there isnt much info..like what their INR were at time of "events' or what other problems did the patient have or who home tested etc. or even the patients age, since it is pretty well known the people who do worse on Coumadin are the elderly, (which most studies classify elderly as 60 and up ish) for several reasons, beside the increased chances of other medical problems, they are often, -NOT always a little frailer, bones are often weaker, skin thinner, tend to fall from standing, more than younger people ..... So it would help to know the ages who had the clots or bleeds and who didnt, of course since everyone who chooses a mechanical valve does it hoping to live a very long happy life w/ less risks of a REDO so, the majority of people with mechanical valves placed when they are young, will one day be "elderly on Coumadin"

. You could go to pubmed and type in the different valves and see what comes up some MAY compare various valves, but you have to pay attention to the year of the study and which valve they are talking about for the companies like SJM and Edwards, who have been making valves a long time and made several different valves. Also the most current information most likely will be hard to find any good information about, since the trials and studies, are still going on and they havent been written up yet. The best way to learn the most up to date information on the trials and studies going on is the various articles or webcasts available from the different doctors conferences, Cardiology, Heart surgeon valve from the US and everywhere else.

But when you read the different studies, you have to pay attention to what they say or dont say, depending on who is running the trials, for example there is a On-x study from early 2000s showing how well they did in poorly anticoagulated patients in South Africa. http://www.ncbi.nlm.nih.gov/pubmed/16480016 where 40% were either not anticoagulated or were unsatisfactorily anticoagulated., I'm Not sure what unsatifactory was, maybe a few low INRs? anyway so 60% were satisfactorily anticoagulated.
This study was one of the main reasons they were able to start the low INR trials.

BUT 2 years previously the same author (with a couple others) from the same hospital did a study on 3 valves, with about 500 patients, http://www.ncbi.nlm.nih.gov/pubmed/15383051 "A comparison of mechanical valve performance in a poorly anticoagulated community".Carbomedics, Medtronic Hall and On-X , that showed "There were no significant differences in the performance of the three valves in the aortic position. In the mitral position the linearized rate of valve thrombosis was significantly higher in the Carbomedics group (p = 0.002)"

But what "I" personally found interesting, was of the 3 valves, the percentage of patients who were NOT "adequately anticoagulated" was much higher for the Carbomedics and Medtronic hall ( both about 60%) than the ON-X (about 40%)
the Carbomedics group 140 valves were implanted in 126 patients (aortic 30, mitral 82, and aortic and mitral 14), 39% were adequately anticoagulated, Medtronic Hall series 224 valves were implanted in 198 patients (aortic 50, mitral 122, and aortic and mitral 26), 39% were adequately anticoagulated On-X series 252 valves were implanted in 200 patients (aortic 44, mitral 104, and aortic and mitral 52), 58% were adequately anticoagulated. Follow-up was 94% complete for a total of 2217 patient-years.
Would that make a difference? I don't know for sure, but My GUESS would be it might have shown better results for the first 2 and slightly worse for the ON-X if they were equally or more closely anticoagulated the same percentage of time..

BUT as far as the
are there any studies who have actually evaluated this?
I thought that given that the OnX valve has now been approved for use with an INR of 1.5-2 in Europe, it must generate less bloodclots (thrombosis) then the others.
Is that assumption correct?
[Why else would be they be able to market this with lower INR?
I guess it is all relative, but there was an interesting thread on what the PROACT trials (so far) showed and didnt show http://www.valvereplacement.org/forums/showthread.php?42468-On-X-CE-mark-and-(unfortunately)-1-5&highlight=PROACT ON-X claims there were the same amount of total events which is true, BUT the lower INR had more clots and higher (normal) INR people had more bleeds.

The High risk group (started w/ 435 total) after the first 3 months when everyone was on 2-3, about 60 people were removed, for various reasons, from not getting a ON-X valve, to death (8) adverse Event (10) or patient stopped,....during that 3 months. so the remaining 375 were broken down 185 in lower inr 1.5-2 and 190 Control 2-3 INR and followed for about 4 years at the time the intermediate results were reported, a mean of about 2 1/2 years. which is important to remember when reading how many people have major bleeds, clots strokes, in that time frame. When you see that of the 190 patients in the control 13 had major bleeds compared to 8 of 185 test patients had major bleeds, or in the lower INR there were 4 CVA (stroke) and 5 TIA compared to only 1 CVA and 2 TIAs in the controls normal 2.0-3 INR group. Whic IMO looks alot like the old saying, more clots but less bleeds at lower INR and higher bleeds but less clots at the higher INR.
Of course this doesnt count the events that happened in the first 3 months, before they were randomized into the 2 groups.


As far as target range for INRs, many people who are given a range, try to stay in the middle of the range feeling that is the "safest" (NOT safe) or the sweet spots where you lower the chance of clots but dont raise the chance of bleed, altho some people rather stay at the lower end or higher end. which is probably why some reccomend a single number as the target., it was rather common a few years ago here for many of the members to prefer to stay at the higher end, w/ the saying they feared clots strokes , more than bleeds, and "you can replace blood cells but not brain cells" . Altho many doctors prefered lower end since the main bleed they worry about is internal bleeds and hemorrhagic stroke, which is usually more devastating than strokes caused by a clot.

FWIW the reason I said "safest' and not safe, was even w/ home testing and the newest best valves, people STILL have problems w/ clots or major bleeds, being in range lessens them, but their still are at least 1-2% of people having bleeds or clots each year, like the PROACT results show.

ps You asked about Homograft earlier, some of the reasons they arent used much any more, is for the last couple generations of tissue valves, they were lasting as long or longer than Homografts, plus they are harder to get since people have to donate them when they die, also the initial surgery or REDO is a little more complicated than other tissue valves http://my.clevelandclinic.org/heart/disorders/valve/youngvalve.aspx discusses the various valves
 
Last edited:

Jamey T

VR.org Supporter
Joined
Oct 12, 2012
Messages
76
Location
South Dakota
Well, my surgeon used a St. Judes, and I found him to be very (almost overly) conservative. But he has an excellent success rate. The nurses also said he was conservative, leaving drain tubes in an extra day, etc. With the reading I have done, I like what I see about the OnyX, but I do trust his opinion. He also put my INR in a range of 2.5-3.5, and my local clinic keeps trying to change to 2.0-3.0 so I fit in the box they are used to.
No real help here, but for what my surgeon chose, there must be a reason. Maybe he just trusted them. Talk to the person that is going to work with it, and get their opinion.
 

tom in MO

Well-known member
Joined
Jan 17, 2012
Messages
999
Location
MO USA
Per your question: Are the different mechanical valve's (St Jude's Regents, ATS or OnX) diffferent i ntheir tendency to produce bloodclots given the same INR? I.e. are there any studies who have actually evaluated this?

The two parts of the question don't really fit the way trials are run. First INR for a valve is a range not a set point. Every valve needs to be evaluated as to the best INR range for its operation. This does not mean that they are compared in the same study.

Not sure if there are specific studies that compare valves. My St.Jude has been around for awhile. It initially had a range of 2-3, which was changed about 2 years ago to 2-2.5. This was based upon research, but probably not comparison to another valve. My cardiologist says my St. Jude is robust and not to worry if I go less than 2 and neither does my clinic. Unlike OnX this information is not publicized by St. Jude. My surgeon knew about the change, I told my cardiologist who agreed, but my clinic didn't know about it. They verified it and agreed to the new range of 2-2.5.
 

Latest posts

Top