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Cactus52

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Hey guys

I’m searching for updated information on INR vs events. I’ll admit that I am terrible at reading chats and graphs and big medical words. I have a Onx valve and have been keeping my INR between 2-3 and my cardio (not my surgeon) wants me to keep it 1.5-2. From the info posted here I believe the data show 2.5-3 is the Sweet spot. But I believe that’s petty old. Any pointers in the right direction would be appreciated.
Scot
 

pellicle

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Hi

From the info posted here I believe the data show 2.5-3 is the Sweet spot.

That's what the data shows, although I'd widen that to 2.5 ~ 4

But I believe that’s petty old.
July 13, 2009
Neither the drug not the human metabolism has changed in that time. So the data remains valid.

HTH
 

tom in MO

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Your valve has been tested and approved for the lower INR range. Mine was 2-3 and now is 2-2.5 and I use the current recommended range.

Ask your cardio if there is any risk of switching to 1.5-2. Pellicle is not qualified to recommend INR ranges for any valve. In addition, he's highly biased to high ranges; he doesn't worry about catastrophic injury and excessive bleeding. He also doesn't have a big dog with sharp nails :) As an aside, usually a surgeon doesn't manage INRs so they won't be the best doctor ask.

The 2009 paper is out of date. In addition, the study was done using a genetically homogenous population, the Netherlands. Onx started out with a higher range but had a trial to lower it. I think it was after 2009.
 

mimi1968

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Your valve has been tested and approved for the lower INR range. Mine was 2-3 and now is 2-2.5 and I use the current recommended range.

Ask your cardio if there is any risk of switching to 1.5-2. Pellicle is not qualified to recommend INR ranges for any valve. In addition, he's highly biased to high ranges; he doesn't worry about catastrophic injury and excessive bleeding. He also doesn't have a big dog with sharp nails :) As an aside, usually a surgeon doesn't manage INRs so they won't be the best doctor ask.

The 2009 paper is out of date. In addition, the study was done using a genetically homogenous population, the Netherlands. Onx started out with a higher range but had a trial to lower it. I think it was after 2009.
I agree with you Tom. I got my On-X valve a month and a half ago and for the first 3 months I have to maintain my INR between 2-3 and then go down to 1.5-2. This only applies to On-X valves.
 

Chuck C

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I have a Onx valve and have been keeping my INR between 2-3 and my cardio (not my surgeon) wants me to keep it 1.5-2. From the info posted here I believe the data show 2.5-3 is the Sweet spot.

I was considering the On-X valve and the St Jude. I ultimately ended up choosing the St. Jude. However, my team made it clear to me that they do not subscribe to the lower INR for the On-x valve. The data from previous studies does not suggest lower events for this lower range. I've read the paper published for the trial which led to the FDA approval of the lower range. As my surgeon pointed out, yes there were fewer overall events, but there were more strokes with the lower range. Given the choice, one might consider whether they would rather have a bleeding event, which increase with higher INR or a stroke, which increase in frequency at the lower range.
Having read the study, one thing which jumped out at me was that for the lower INR arm of the study, the average INR was 1.9. Now, true, that is within the 1.5-2.0 range, but that is clearly at the higher end of the range. I'm not sure if they intentially targeted the higher end of the range or if it just happened that way by chance. So, if one was convinced by this study to go with the lower INR range, if you really wanted to attempt to achieve results consistent with the study, something which might be considered is targeting an INR of 1.7-2.1, which should over time average 1.9. Such a tight range is probably not realistic unless one is home testing. Which brings up another point.
Home testing was used in the trial. Anyone who is considering this range should really consider self testing. Testing at the lab, folks generally go 4 to 6 weeks between tests. From time to time we fall out of range and need to make adjustments. The idea that someone would potentially slip below the low side of a 1.5-2.0 range and not get the data leading to a correction for 4-6 weeks is really troubling.
Another point often overlooked is that those in the study were on low dose aspirin.

Anyway, these are all points to discuss with your cardiologist. Ask him how safe he thinks the low end of the 1.5-2.0 range is given that the average INR was 1.9 for this low INR group in the trial. I wonder if he actually read the study. I certainly hope he did.
 
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pellicle

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Chuck

Such a tight range is probably not realistic unless one is home testing. Which brings up another point.
Home testing was used in the trial.

agreed, and a point I often mention.

I find it interesting when members here say not to listen to another member and only listen to their doctor and then go on to provide their own advice too (including why surgeons wouldn't know) while not citing a single source of data. Seems like a contradiction (or is it hypocrisy 🤔)
 

Superman

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Beyond FDA concession (I mean approval) , Warfarin = scary / bad, and On-X marketing, has your cardio given you any updated info including studies, charts, and big medical words that would support, to your comfort level, that 1.5 - 2.0 is somehow better than 2.0 - 3.0 with fewer negative events? Feel free to challenge your provider. Surely they aren’t just following the marketing narrative. They are a Doctor after all.

Remember that the FDA is a consumer protection entity. They are not a medical group. They simply allow things that are deemed safe enough. They don’t endorse things as the best choice for patients. And it’s a litigation protections for providers (you probably won’t lose a lawsuit because it’s FDA approved).
 
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Chuck C

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Remember that the FDA is a consumer protection entity. They are not a medical group. They simply allow things that are deemed safe enough. They don’t endorse things as the best choice for patients. And it’s a litigation protections for providers (y

This is a very good point and one that is often lost. They agreed to allow the lower range for On-X. It does not amount to the FDA advocating this range over a higher range and it does not amount to the FDA claiming it is safer; only an approval which was justified because those reviewing the trail at the FDA felt that the results were reasonable enough to be approved. It should be kept in mind also that the controls were tight for INR management using frequent home testing in addition to aspirin in the study. Given how much was at stake for the manufacturer, you can bet that they had the A-team warfarin management folks in place giving dosing guidance following the feedback from the home testing.

Some data which I wish they would have published was how often the trial participants were out of range. Every large study I've seen indicates that patients are out of range often, typically 50% to 70% of the time. Those of us who home test and are diligent about not missing doses know that we achieve much better results than this. A trial is going to have closely monitored INR and such a trial with home testing, one would expect, is going to have participants who are probably in range with much more frequency than the general population.

In other words, I'm in range about 95% of the time with home testing. From forum comments I know that others who home test get similar results. I would expect, under trial conditions, that their results would have been similar to this. And it appears, from the average INR of 1.9 in the low INR arm of the study, that the guidance erred on the high side of the range. Can this data then be appropriately applied to the general population who might be in range 50%-70% of the time? Even if the range was approved as "reasonable", why would anyone assume that this will be better given the data that the range of 2.0-3.0 INR has so few events?
 

Chuck C

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Frankly, for me, I would find a 0.5 window stressful. I don’t care where it sat. I’d take 1.5 - 2.5 or 2.0 - 3.0 or 2.5 - 3.5 over a 1/2 point window.

True. Historically ranges have had a 1.0 window. So, in the studies that find 50-70% of the people out of range, that is with a 1.0 target window. With a narrower target of 0.5, the % of times that people are out of range is going to go up, statistically. Not much of an issue going out of range to the high side, as they then enter the range associated with the lower events historically. I suspect they knew this, and probably why the average INR was 1.9- I don't think that was accidental. The concern is being out of range on the low side of 1.5.
 
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Lynn

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According to my surgeon, the On-x trials included a low dose aspirin. As I am allergic to aspirin my surgeon suggested I keep my INR over 2. I knew this when selecting my valve and went On-x anyway as my surgeon has installed hundreds and I wanted him to work with what he knows. I did receive a letter from On-x just last month informing me that the valve is approved for the lower range, but given my situation I disregarded it.

I think this illustrates the need to look at your own situation-other health issues, home testing (as some have said)and lifestyle.

I also agree that aiming for and INR that provides a ”margin of error” makes sense. Your INR will vary, so what I ask myself is am I at risk if I am .5 lower? Am I at risk if I am .5 higher? That‘s why I shoot for 2.5. I don’t want the risk of beiing below 2. And if I am at 3, that doesn’t seem to pose much risk.

Lastly, I have a question regarding this push towards lower INR. Other than a very slight lower risk of bleeding when you cut your finger, are there other health benefits? Has anyone seen any studies on the long term impacts to health on say an INR of 1.5 vs 3?.
 

Lynn

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Further to my last post, I should say that my INR doesn’t very much for whatever reason (genetics, lifestyle) So giving myself a margin of error of.5 seems to work. (I have only been out of range once in a year when I had a stomach bug). If you are someone who sees wider and more variable readings in your INR I would take that into account.
 

Superman

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Lastly, I have a question regarding this push towards lower INR. Other than a very slight lower risk of bleeding when you cut your finger, are there other health benefits? Has anyone seen any studies on the long term impacts to health on say an INR of 1.5 vs 3?.

I’ve targeted 2.5 - 3.5 for over 31 years now. So far no issues other than grey hair, I didn’t need reading glasses when I started, and I’ve had five kids since going on Warfarin. I’m also about 30 lbs heavier than when I started taking Warfarin at 17. Everything else seems fine though. Blood work and blood pressure has always been normal.
 
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vitdoc

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Being in the health care industry I have seen much over the last forty years concerning FDA approval and hype from drug/device manufacturers. I was unimpressed with the ON-X data. They concocted a statistic which added bleeding with stoke type issues into a single statistic. So if you don't mind the stroke side of things but are more worried about bleeding than by all means go for a low INR. Personally I am not a big stroke fan. Once something like this gets out and is approved the fine details of what went into the approval are lost in the mist of history. So surgeons get bombarded by detail people about how great their drug/device is and how crummy the other guy's product is. So it is very easy to get swayed by all the bullshit thrown at you. As everyone has said also it is really tough to guarantee that one doesn't go much below 1.5 if the goal is 1.5-2.0. So personally I go for 2.5-3 with my St. Jude. And I would do the same with the ON X if I had one.

The other thing I find amusing is the idea that medical people have all the answers. No one takes a course in using warfarin. Probably in pharmacology is is discussed in a single lecture. Then physicians if they are curious and care about details will read papers when they come out about warfarin and it's use in valve disease. After that they are influenced by what they have done in the past, where they trained, personal bias and the stuff they get fed from the drug/device manufacturers. So ask detailed questions about the use of warfarin from the cardiologists when you are contemplating going for a 1.5-2 INR.
See if you think the answers are founded on good information not just FDA approval.
 

pellicle

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tatistic which added bleeding with stoke type issues into a single statistic. So if you don't mind the stroke side of things but are more worried about bleeding than by all means go for a low INR
a phrase I learned here is: "Its easier to replace blood cells than brain cells"

something I've learned in life is that quite a many folks make more use of blood cells than they appear to of brain cells ...

I find that in so many aspects of understanding people and how they react to the world, Carl Jung is insightful
1649886118660.png


Like you I would seek to avoid a stroke (and also perhaps obstructive thrombosis).

Its unfortunate that a member experienced this (btw, to the casual reader the problem wasn't with the valve it was with the protocol_, and it makes me wonder how many more there are out there:


but you should definitely seek the opinion of your doctor, they know more than some random person on the internet (who's grand child may have dismantled and reassembled their Coaguchek rendering it randomly inaccurate).

Best Wishes
 

pellicle

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Good thing I’m mostly Dutch. 😁
well, don't hold too much faith in that, not only is The Netherlands subject to a lot of migration it would appear it always was


you may not be as homogenous as you thought.



I love science, but I know I'm not a scientist.
 

tom in MO

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Chuck



agreed, and a point I often mention.

I find it interesting when members here say not to listen to another member and only listen to their doctor and then go on to provide their own advice too (including why surgeons wouldn't know) while not citing a single source of data. Seems like a contradiction (or is it hypocrisy 🤔)

Citing a 2009 study in a homogenous population for the range of a different modern valve is claptrap. In science, one study is not a fact and a homogeneous population makes one study less relevant.

I did not say to only listen to your doctor, but to ask these questions of the physician who says 1.5 is safe. That’s just common sense.

What I would also ask my cardio is whether or not the meter he was prescribing was accurate down to 1.2 since the low end of his prescibed range is 1.5. I have no trouble maintaining a 2-2.5 range for ~10 years but some meters might not be designed for a lower range.
 
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