On-X low INR target

[Al3x]

A case study has been published on the 1.5 - 2 INR range for the on-x valve. It supports the caution many of us have over that lower target.

https://www.cureus.com/articles/286...rrent-thromboembolic-strokes-a-case-report#!/

 

[Chuck C]

"The target INR was increased from 1.5-2 to 2-2.5, and oral aspirin was added."

The 1.5-2.0 INR range is only supposed to be used with aspirin. If his cardiologist had him at 1.5-2.0, he should have had him on aspirin. Apparently aspirin was only added after the event, when the INR was also shifted up. It seems that cardiologists sometimes forget this very important detail.

Also, his INR was at 1.4 when he had the first stroke. This is the problem with the low INR range of 1.5-2.0. It is risky enough in that range, but the risk goes up much higher when below the 1.5 point. Those in the PROACT trial did home testing and had tightly controlled INR with an average INR of 1.89, near the high end of the range. Most people don't self test. The average person gets tested every 4-6 weeks at the lab, unlike those in the study. People do go out of range from time to time. With a range of 1.5 to 2.0, you are already in a high risk zone for strokes and there is not any margin with the risk of falling out of range into a very high stroke risk zone, below 1.5. Now, add to this that you might not find out you have gone out of range for 4 to 6 weeks and it could spell tragedy. We all go out of range from time to time. The idea of potentially being below an INR of 1.5 for weeks should be very concerning. I see major issues with the low range, but if a cardiologist is going to put his patient on such a low range, it seems weekly self testing or weekly lab testing would be the way to go, so that correction can be made before too much time passes if the patient falls below range.

We keep hearing more and more stories of those on On-x whose cardiologist moves their target INR range to well above 2.0. Events have a way of influencing these decisions.

 

[3mm]

We keep hearing more and more stories of those on On-x whose cardiologist moves their target INR range to well above 2.0. Events have a way of influencing these decisions.

Chuck C - I know you carefully manage your INR before boxing. Do you see (or feel) a difference in bruising as your INR varies between 2.0 and, say, 3.0?

I have seen a lancet poke for an INR test take a minute longer to stop bleeding when my INR is around 3.0, versus when my INR is around 2.0.

 

[Chuck C]

Chuck C - I know you carefully manage your INR before boxing. Do you see (or feel) a difference in bruising as your INR varies between 2.0 and, say, 3.0?

I have seen a lancet poke for an INR test take a minute longer to stop bleeding when my INR is around 3.0, versus when my INR is around 2.0.

I have not noticed any difference in bruising. Although, I've never bruised much, even on warfarin.

 

[Protimenow]

INR test results should not be considered to be 'accurate.' IIRC, it was the WHO (World Health Organization) (or some other standards body) that concluded that test results +/- 20% of actual (and who knows WHAT actual INR is?), the result should be considered accurate. This is because INR isn't an exact number like, for example, blood sugar. Although INRs taken on more than one CoaguchekXS, for example, may be identical or very close to each other, lab tests on the same blood draw could vary by a few percent.

The point here is that if a person aims for a target of 1.5 - and has 1.5 as a result - if you apply the 20%, this means that the actual INR could be as low as 1.2 -- obviously a dangerous value, whether or not you take aspirin. Aiming at 2.0, the lowest value will probably be 1.6 - although this is too low as far as I'm concerned (and I'm only speaking for myself here).

A person's life will be no different with an INR around 2.5, but the danger of stroke would be reduced.

FWIW - I use automatic, one use lancing devices - 29 gauge, with a pre-set depth. I don't press the device very hard into the skin. I've had no problems with excessive bleeding when using these lancets. (A paper towel pressed against the lanced finger stops the bleeding quickly - usually less than a minute, sometimes a bit longer.

I wonder if you may be setting the depth of the cut too deep or are pressing the lancing device too firmly against your finger. An finger incised for an INR should stop bleeding fairly quickly - especially with the help of a kleenex or paper towel pressed lightly against it.

I've been self testing and self managing for only 15 years, have worked with a lot of lancing devices, and haven't really run into trouble getting the incision to stop bleeding.

 

[pellicle]

A case study has been published on the 1.5 - 2 INR range for the on-x valve. It supports the caution many of us have over that lower target.

Much has bee written here cautioning the validity of the On-X lower INR protocol over a longer period (more than 5 years). Stuff like this article

36-year-old male, the background of On-X AO replacement but no other risk factors, developed thromboembolic stroke twice while on Warfarin, first with INR 1.4, second with INR 2.4. .... The INR range was increased to 2.5-3.5, and aspirin and statin were added.

Aspirin was also required during the certification of the lower INR. The article makes it clear that the broader body of evidence remains applicable and that the On-X is not magical but marketing.

Follow the data

 

[pellicle]

WHO (World Health Organization) (or some other standards body) that concluded that test results +/- 20% of actual

Can you please provide a reference for this assertion?

If you've going to cite the WHO (or some other standards body) then cite them

I found this

https://www.ncbi.nlm.nih.gov/books/NBK507707/

The INR value from POCT is considered acceptable if it does not exceed plus or minus 0.5 INR units by the reference laboratory INR value.​

which is not a standard but something like a guideline. This does suggest that 20% is "acceptable", but nowhere in that does it say that WHO (or some other body) has said that. Conflating an idea with an organisation is a weak ploy to "substantiate" the value of what you have claimed (and I'm being polite here).

On the subject of "reference laboratory" its important to note that same book has this statement in it with reference to the handling of samples:

It is recommended by the Clinical and Laboratory Standard Institutes (2017) that the blood specimens for INR/PT testing in the laboratory setting should be collected from venous blood and it is directly obtained into a tube with a light blue top. The tube contains an anticoagulant. The acceptable anticoagulant is the concentration of sodium citrate 3.2%. The tubes must be filled to within 90% of the full collection volume. The tube should be then inverted a few times, gently and as soon as possible, for proper mixing with the anticoagulant. The total time between sample collection and testing should not exceed 24 hours.​

That whole collection procedure is important ... each and every part. If anything is not done right you won't be getting reliable results no matter how accurate (or inaccurate) the Lab getting the sample is.

I stand by my Coaguchek in my own testing its been no more than 0.2 INR units away from lab.

 

[Protimenow]

Pellicle: I'll have to look for it. If you'll refer to my comments, before mentioning the 20% figure, I said IIRC (if I recall correctly). Perhaps I didn't recall it correctly.

When I get a chance, I'll look for it.

My point here, though - and you stand by your XS to be +/- .2 is that people who come up with a result of 1.5 may be almost as likely to have an INR of 1.3 as they are of having an INR of 1.7, according to your statement. I can't see many people taking comfort at the possibility of having an INR of 1.3 - even if the meter says 1.5.

(FWIW - I have more than one XS. I occasionally test, using same strips and chip, using my XS and my XS pro and, although the time to clot may be slightly different between machines (by tenths of a second), INR readings are usually the same - or within .1 of each other.

 

[pellicle]

My point here, though - and you stand by your XS to be +/- .2 is that people who come up with a result of 1.5 may be almost as likely to have an INR of 1.3 as they are of having an INR of 1.7, according to your statement. I can't see many people taking comfort at the possibility of having an INR of 1.3 - even if the meter says 1.5.

everything you say here is exactly why I say "do not hover on the lower limit of the range" I say "always aim for the center of the target". This is why we now see "Target = 2.5" given and "range of 2 ~ 3" is old school.

even experienced shooters get outliers with good equipment (no this isn't mine)

You'll also note that I said for me ... I ... because I want to emphasise the following "this is only for me, you need to test and see for yourself"

Also, as one who has said they worked an editor of science oriented magazine I hold you to a higher standard than "just anyone".

 

[Protimenow]

These magazines were computer technology - not hard science. This was a while ago - I still try to maintain standards, but some of what I say comes from things that I read a while ago - I can't always easily find (or cite) these source articles.

Agreed - 2.5 is a good target even for On-X valves.

 

[Habana58]

got the OnX in nov-2015 and for about 2 years used the 1.5 -2.0 with 81 mg aspirin, it was stressful for me at the end because as others have said here, sometimes you will be below 1.5; so i ended up testing every 4 days and decided to move to 2 - 3 and NO daily aspirin; i do take 1 aspirin once a week; most of the time i am somewhere between 2.3 and 2.6, today it was 2.2 no big deal it is above 2 so all good, but with the 1.5 -2 i did on a couple of occasions dropped below 1.5 and that is the problem unless you test every 3 days but that unless there is a special need for it like an op or procedure it is too much hassle and adds up $$ cost, other than that very happy choosing a mech over tissue the dilemma of "when is going to fail" is out of my concerns, and my surgeon who is #2 in the country "only" uses OnX due to its 90 degrees flip design, not saying here that a rabbit is better than a turtle, is not the point nor like that kind of trends here at times, one of my friends has a ball in cage for 41 years , go tell her that valve StCowPig is better than hers she will laugh at it because the point is not what is the latest model, but the fact that what you got works, of course talking mechs , the tissues are great if you love hospitals.

 

[pellicle]

Hi

... your post seems to indicate what I'd expect. I have an ATS valve and do about the same.

so i ended up testing every 4 days and decided to move to 2 - 3 and NO daily aspirin; i do take 1 aspirin once a week;

on the above however I found that as I aged (I'm 60 now) I returned to Aspirin as I was having occasional "little warnings" of a TIA which went away with 150mg of Aspirin every second day. I feel that this is actually better than 75mg daily because it gives my body some time to generate a small number of fresh platelets in the time outside the half hour half life of aspirin window.

Best Wishes

ps:

and my surgeon who is #2 in the country "only" uses OnX due to its 90 degrees flip design

you should suggest he review this paper:

https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4559772/

which shows actual measurements like this:

valve	CT Measurement	Manufacturers' Value	P
On-X (n = 10)	79.0 ± 2.1	90	< 0.001

 

[Protimenow]

A few things:

You probably don't have to test 'every 3 days' -- many (most?) of us do weekly testing, and it's working out well for us.

The INR testers DON'T detect the results that aspirin has on the platelets. It probably doesn't matter AT ALL, in terms of testing with a meter, how much aspirin you take (although the amount of aspirin CAN become an issue if you take too much, or if it burns your stomach.

I'm not sure about the $$$ cost in an emergency because your INR is too high. Doctors seem to know how to work around too much anticoagulation, and if a procedure can be delayed, Vitamin K should reverse the effects of warfarin within a day or so.

As for aspirin -- I've been taking 81 mg daily - I may do like Pellicle, and take a larger dose every other day (for me, 2 81mg every other day). I'm not taking it for anticoagulation reasons: a presentation that Pellicle linked a few months ago suggested that aspirin has an anti-cancer effect.

Pellicle - I'm fitting a lot of things in here -- my reference to the +/- 20% for INR was in an ISO document. I'm locked out, so I can't find the specific document that I cited.

 

[vitdoc]

A case study has been published on the 1.5 - 2 INR range for the on-x valve. It supports the caution many of us have over that lower target.

https://www.cureus.com/articles/286...rrent-thromboembolic-strokes-a-case-report#!/

I love the way this report starts: "Although the On-X aortic valve (AO) is considered less thrombogenic compared to its counterparts, we present a case where recurrent thromboembolic ischemic stroke occurred"
I am not aware of any head to head comparison of valves that show the above assertion is true. The On-X company had the guts to do the low INR study which has been mentioned was a rather unimpressive study. So by the fact that the company did the study the valve is now being touted as "less thrombogentic". The company got what it wanted. You can bet that many physicians will buy into this and will recommend the valve over alternatives.
Great marketing.

 

[pellicle]

You can bet that many physicians will buy into this and will recommend the valve over alternatives.
Great marketing.

It's sad really, that such educated folks don't apply critical thinking.

 

[Chuck C]

I am not aware of any head to head comparison of valves that show the above assertion is true.

There was a head to head study comparing On-x to St Jude. Much larger study than the PROACT trial. They were found to be equal in terms of TE events and mortality. The idea of On-x being less thrombogenic is marketing fluff, but it has been a highly successful campaign, based on market share gained with the claim.

In the linked study, they were not only equal, but the TE events were low for both valves. It should be noted, however, this good result was obtained with a target of 2.2 to 2.8 INR for the aortic valve and 2.5 to 3.5 for mitral.

"The target anticoagulation level for both prostheses was: for aortic position prostheses international normalized ratio (INR) between 2.2 and 2.8, and for mitral position prostheses INR between 2.5 and 3.5"

"The overall freedom evaluation showed no differences at 5 years between the prostheses for thromboembolism or for valve thrombosis. There were also no differences in mortality."

https://www.jtcvsopen.org/article/S...ions,Developing more than Western populations.

 

[Habana58]

No daily 81 mg aspirin for me, just once a week, and OnX yes, no doubts is an improvement over St Jude, but that does not make St Jude less, is just an older design, again, my friend has a Ball in Cage for 41 years and the girl still going and going, so what each got was what was available at the time; some loved Studebakers in the 50s and then something else in the 60s, not that any of those was really good compared to a 2000 Audi

 

[pellicle]

my friend has a Ball in Cage for 41 years and the girl still going and going

@dick0236 too, around 60 years in his case

 

[Habana58]

Just forgot to mention earlier, yes asa does not influence INR level, but it does increase risk of bleeding, that is why i only take it once a week, not looking for controversy, we all have different bodies and they operate in different manners under specific personal conditions.

 

[Chuck C]

No daily 81 mg aspirin for me, just once a week, and OnX yes

But, when you were at INR of 1.5 to 2.0 you were on aspirin. The FDA has approved the 1.5 to 2.0 range for On-x, but only with low dose daily aspirin. Now that you have INR range of 2.0 to 3.0, the guidelines do not call for daily aspirin, and it is more of a gray area at that point- differs cardiologist to cardiologist and patient to patient.