Low INR question

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Protimenow

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On another forum, the research that showed the very limited evidence supporting an INR of 1.5 - 2.0 for On-X didn't provide long-term follow-up, and was a very limited study. If I had an On-X valve, I wouldn't bet my life on the results of this limited study. It's not a big deal to live with an INR of 2.0 to 3.0 (more difficult to keep in range between 1.5 and 2.0, or between 2.0 and 2.5 - especially because these numbers can't be considered to be 'exact,' anyway).

It's difficult to keep INR between 1.5 and 2.0, just as it's difficult to keep it between 2.0 and 2.5, or 2.5 and 3.0. That's the nature of INR testing - it's not exact, management isn't as easy as dialing up a 'dosage' wheel and locking it in. The issue with On-X isn't that it's hard to maintain 1.5 - 2.0 -- the risk is higher than the benefit of not having to maintain a slightly higher INR.

Perhaps I don't believe that 'high is good' -- I believe that 'high (2.0 - 3.0 or so) is SAFE.' There's a difference.

The reason for this group of biased ignoramuses (ignoramusi?), myself included, advocate for ranges above 2.0 - even for On-X - is that the slightly higher INR is protective and doesn't alter lifestyle or daily activities any more than a 1.5 - 2.0 does. WHY NOT BE SAFE?

A paper, May 18, 2015, from the American College of Cardiology specified a 'target' value of 2.5 for Aortic Valves, with a range of 2.0 - 3.0 (most likely because it's not possible to 'hit' and maintain INR at that target). For a mechanical Mitral valve, it's .5 higher.

Global RxPH also shows a target of 2.5, with a range of 2.0 - 3.0.

If it's possible to maintain a range of 2.0 - 2.5, as your clinic wants to do, this range will be ignoring the recommended range of 2.0 - 3.0. It will ignore the recommendation that 2.5 - 3.0 is ALSO within the recommended range. SO - we (the 'higher is better' bigots) aren't actually advocating for INR that's out of range - we're just advocating for the use of recommendations as recent as those from 2017. I'd like to see what you're quoting as the source of this recommended 'narrower' range. I don't think it really makes much of a difference, anyway.

The 'attractiveness' of a valve that may require lower INR (ON-X) is pure marketing B.S. You still have to take Warfarin (I haven't seen where one 81 mg aspirin a day is adequate), and you still have to take your INR. Where's the benefit? The other valves have decades of positive results - I'm not sure what the On-X delivers aside from slightly better design (maybe) and materials (maybe), and a still unproven ability to function at lower INR. (Perhaps the manufacturer should play up the possible advantages, and ignore the bogus claim about INR). (Perhaps, in a few years, something else will come along, and none of this would matter to patients getting new treatments).

One other thing -- the CoaguChek XS has a history of reporting .2 or so above labs. If your INR, according to a CoaguChek XS is right at 1.5, it's not impossible that your LAB results would be closer to a spot slightly UNDER 1.5. Personally, this biased 'higher is better' bigot would rather have an INR above 2 for an On-X valve than to keep it below 2. If I was convinced that 1.5 on a CoaguChek XS is safe, would a lab's 1.3 ALSO be safe?

Until long term studies confirm that it's safe for On-X recipients to maintain INRs between 1.5 and 2.0, I wouldn't want to take - or recommend - that risk.

---

Disparaging comments have been made about the clinics because some clinics deserver to be disparaged. These clinics often use outdated and, in some cases, completely inaccurate protocols. ANY anticoagulation clinic that wants you tested every month, or even less often, has a real problem keeping up with the literature. It's irresponsible to test that infrequently - unless the clinic knows that you also test weekly with your own meter. (There's abundant literature that says people who self-test weekly are in range for longer periods than clinics that test less frequently - weekly self-testing is a standard of care). I've gone to a clinic that used outdated protocols - and these protocols come from the medical 'experts' -- not the technicians at the clinic. Worse, the people in the clinic could not deviate from the protocols or make changes from the protocol's recommendations.

You won't get an argument from me to your comment that the clinics probably know more than your cardiologist or surgeon. They probably DO. But there's a medical director somewhere, and the protocols defined by that medical director may be outdated or just incorrect.

---

I haven't polled the 'majority of the medical profession involved in Warfarin therapy' as you must have, so I don't know their recommendations, but I would be surprised to see the overall recommendations for mechanical valves (other than On-X) being 2 - 2.5. My doctors have never suggested this. It's hard to keep within that narrow a range.

If you don't mind risking a stroke, pulmonary embolism, or other pleasant 'gift of the day,' set your INR as low as you want. If not, there's really no harm listening to us idiots advocating for ranges above 2.0 -- even for On-X valves.
 
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tom in MO

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The general range for mechanical valves in the aortic position is 2-3. AFAIK, the range of 2-2.5 is specific for St. Jude mechanical valves and it's well accepted. Like the range for Onyx is 1.5-2. There are general ranges and valve-specific ranges.

When it comes to a 0.5 range being hard to keep, most people can stay within a 0.5 INR most of the time but it probably requires home testing at least every 14 days. Of course, being humans, there are outliers.

Just a little thought on why one would not want to "run high" with one's INR. Many people get prostatitus, ulcers and hemorrhoids, anticoagulation does not help these conditions. There are lots of people who need NSAIDs for arthritis or orthopedic reasons. Your risk of ulcer increases while using these and the risk of a bleed is compounded by a higher than needed INR. I just got a dog bite...scabs break open and bleed more for any wound while on warfarin. Wouldn't want that infected cut that keeps breaking open to wind up as endocarditis.

Maybe its because I have studied and worked with chemicals, pharmaceuticals, toxicology and how they intersect into our lives. I have developed a philosophy to use only the drugs you need and at the minimal effective dosage for the amount of time prescribed. I've seen drugs go from being wonderful, to being damned to be wonderful again (think aspirin.) My personal feeling toward my INR is to find experts, listen, check, trust and verify, but try not to sweat the details.
 

Protimenow

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Tom, I'm sorry, but I may just have to take the gloves off.

You said that the range for a St. Jude valve is 2.0 - 2.5. I cited two different papers saying that the range is 2.0 - 3.0, with a target of 2.5. I asked you for the source that you quoted, and have seen none. And you said that this range is 'well accepted.' By who?

You also state a range of 1.5 - 2.0 for the non-existent 'Onyx' valve. Do you mean On-X? Or does this low range only apply to the Onyx?

You said that most people can stay within a 0.5 INR - but that they will have to test 'every 14 days.' Testing every 14 days can be dangerous, and research that specifies self-testing every week (not every TWO weeks) has been shown to be the best way for people taking Warfarin to keep their INRs in range. I had an issue last week, where I made up a too small dose of warfarin for a week - I caught it after only one or two days under 2.0. If I tested every two weeks, I may have had a stroke before I caught my error.

I'm assuming that you meant 'prostatitis' (itis means inflammation - itus is used for tinnitus, ringing in the ears that has nothing to do with inflammation), hemorrhoids, and ulcers. You threw in dog bites, for good measure. Maintaining an INR below 4.0 isn't going to materially affect the bleeding times for any of the things you mentioned (I don't think prostates bleed, so lower INR shouldn't make a lot of difference) -- unless the dog mistook you for hamburger, and did a lot more than puncturing the skin...if an artery was cut, INR would make little difference in the clotting times. Yes, taking warfarin will result in more bruising, but I'd rather have a bruise than a stroke.

As far as throwing around what you've worked with, Pellicle can wave credentials at you, we have doctors on this forum who take warfarin and have patients taking it, personally, I've run a Tumor Registry at a major medical center, I'm trained in Biostatistics and Epidemiology, and I was involved in a major multinational pediatric cancer research program.

I, too, believe in least effective dose - but NOT for Warfarin. Warfarin is not intended to 'cure' a condition - it's not made to improve my heart's rhythm, it's not intended to knock out an infection, It's not intended to reduce blood pressure, it's not intended to improve prostate function, it's not intended to improve thyroid function, it's not intended to (fill in your own list). Warfarin is designed for one purpose -- to reduce the ability of blood to form clots -- for people with A-Fib, this was used to reduce the risk of clots forming on chambers of the heart (it's still indicated for it, but newer drugs have mostly replaced it), in the case of people with prosthetic heart valves, it's meant to reduce or eliminate clotting on valves and related surfaces. For people with deep vein thrombosis - this can help reduce the clots and reduce further risk of clotting. It's for PREVENTION of clot formation. It's for MAINTENANCE of blood in a state that won't clot as readily as it does if unanticoagulated. In this case 'least effective dose' makes little sense -- unless you take into account that 'least effective' dose is the dose that has been well proven to prevent clots from forming. (and it's not a minimum dose - it's a safe dose)

For now, I don't think I would want to risk my life on keeping a slightly lower INR with an On-X valve (if I HAD an On-X valve).

As far as finding 'experts' -- that's good. But be sure that your 'experts' know what they're talking about and are not just parroting the 'low INR' stuff that drug reps feed them.

When it's your life on the line, you SHOULD sweat the details. Make sure that your INR is at a safe level. Don't take chances on the still not fully proven theory that a lower INR is safe for a particular valve. SWEAT the details.

Please.
 
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Keithl

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I test twice a week and I swing usually in a .7 range between 2.3 and 3.0, but most readings are 2.3-2.7. I have been on a very consistent dose, but recently bumped up another .625 as I was bumping along 2.1-2.3 and I am targeting 2.6 - 3.0.

I would never go 14 days and I actually like twice a week because I can see trends vs. diet and other impactful changes.
 

pellicle

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I would never go 14 days and I actually like twice a week because I can see trends vs. diet and other impactful changes.
interestingly if you read the methodology of the PROACT trial for the On-X they tested weekly, so myself I think its difficult to make a sound case for 14 days between testing ... especially if running on the "edge" 1.5 to 2.0 ... but I think it was well phrased above:
If you don't mind risking a stroke, pulmonary embolism, or other pleasant 'gift of the day,' set your INR as low as you want. If not, there's really no harm listening to us idiots advocating for ranges above 2.0 -- even for On-X valves.
 

pellicle

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...
When it's your life on the line, you SHOULD sweat the details. Make sure that your INR is at a safe level. Don't take chances on the still not fully proven theory that a lower INR is safe for a particular valve. SWEAT the details.
I think you summed it well earlier: If you don't mind risking a stroke, pulmonary embolism, or other pleasant 'gift of the day,' set your INR as low as you want. If not, there's really no harm listening to us idiots advocating for ranges above 2.0 -- even for On-X valves.

I mean its not like we've seen posts here saying there were long term problems:
https://www.valvereplacement.org/threads/failure-of-onx-valve-and-problems-with-lowering-inr.878615/

I guess that's just one of those ones that's rare and you can chalk it up to "it won't happen to me" because ...
 

pellicle

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AFAIK, the range of 2-2.5 is specific for St. Jude mechanical valves and it's well accepted.
Before Protime asked, I wasn't going to bother with asking you, but can you supply any reference on how well accepted this is? For everythinng I know is Target = 2.5 or Range is 2.0 ~ 3.0 ...
For instance
https://www.acc.org/latest-in-cardiology/articles/2015/05/18/09/58/anticoagulation-for-valvular-heart-disease

No mention of supporting lower or tighter ranges in there ... I personally don't mind what you do (heck you can go off it if you wish, that's been demonstrated to be ok for periods too) but if you are going to write something in a public forum I would ask that you provide some basis for your assertion (particularly when unorthodox).

Thanks
 
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dick0236

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Since the INR procedure started (I've been on it from the beginning) my INR range has been 2.5-3.5 with no bleeding.....or clotting problems. Prior to the adoption of INR my PT was maintained at "1.5 X normal PT (12 sec.)", about 18 seconds (I think).......that's equivalent to an INR of about 1.7(I think) and I had my one, and only, stroke after going without warfarin for a few days. Prior to INR AC management was, more or less, done by the seat of the pants theory.

I would drive myself "nuts" if I tried to maintain a .5 INR spread........I need the full 1.0 spread from 2.5-3.5........and I use it all. :p
 

Protimenow

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It's rather amazing that the cardiologists, cardiac surgeons, anticoagulation clinics could be manipulated into thinking that a 1.5 - 2.0 is okay with the On-X -- or with ANY prosthetic valve. The underlying 'research' is too sketchy to be relied on, there's no long-term tracking of survival rates for patients with INRs maintained that low, there are decades of positive survival rates for the other mechanical valves maintained at INRs of 2 and above. There's a long history of users of St. Jude valves maintaining INRs from 3.0 - 4.0 without catastrophic bleeds.

Instead of free meals, free golf tournaments, high pressure drug reps, a few boxes of ballpoint pens, writing tablets, and maybe wall clocks that carry a brand's logo, these 'professionals' should apply a bit of scientific rigor before digging their spoons into the bags of manure that are being pushed at them.

(And, again, as we've seen on this forum, there are patients trusting enough to believe whatever they're told. 'Hey, this doctor is a professional. He MUST know what he's doing' WRONG)
 

tom in MO

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The St. Jude 2-2-5 range I read about. It was before my surgery and my cardiologist said the new range was real. I asked my surgeon who originally told me 2-3 and he said follow the cardio's treatment plan. At my last appointment with the surgeon he said that he too had recently read it was 2-2.5. I've been through two cardios so far and have had two coagulation doctors and they all say 2-2.5. My cardio says my model of mechanical valve is proven and that I can go very low for short periods of time for surgeries or procedures and I have. It's worked for 7+ years for me.

When it comes to testing frequency, the minimum is 1-month. That's for blood draw patients. That information comes from people who only test once a month not any literature. That's just for warfarin-eaters, not valve specific. There's a lot of people who take warfarin for other reasons. I occasionally meet people who complain about their elderly relatives and warfarin therapy. I try to steer them to home testing. Sometimes they know but haven't made the effort to pay attention or ask. For some people, getting a blood test for your INR can be a chore or an obstacle especially when you are old and don't like traffic.

The two-week testing frequency is common and is what my health care team suggests. However, my insurance company allows for weekly testing, that's the maximum. My coagulation clinic prescribes the maximum so you have a steady supply and can test more often when things go out of whack. Even when the INR goes out of whack, given the lag time of a change in INR vs. change in warfarin dose (or salad binging) testing more frequently than 5-7 days is a wasted strip. The very few times I've been out of my 2-2.5 range by a lot, they asked me to test in 5-days (low) and 7-days (high.)

Believe what you want, I don't see a need to search the internet to support everything in rebuttal. There is knowledge outside of Google.
 

Astro

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The American Heart Association recommends (2017),

“For bileaflet tilting disc valves in the aortic position, the target INR is 2.5 (with a range of plus or minus 0.5)”

“For valves in the mitral position, older mechanical aortic prosthesis, or mechanical AVR with additional risk factors for thromboembolism, the target INR is 3.0”

To me, either 2.0 - 2.5 or 2.0 - 3.0 is reasonable. I doubt there would be trials comparing these two ranges as targets for INR control. Clinicians tend not to follow guidelines religiously. This can be viewed as dangerous variation or as reasonable variation considering the ambiguity of the literature and the differences between patients. It makes sense for anyone who has had a thrombotic problem to run a higher INR and people who have bleeding problems to run lower.

Personally I found the PROACT trial less than convincing that 1.5 - 2.0 is safe for the long term for On-X. However, this trial tells me that there is no reason to panic (for example, get a low molecular weight heparin injection) if INR temporarily drops between 1.5 - 2.0.

I don’t see a huge difference between modern bileaflet pyrolytic carbon valves so I think that it is reasonable to extend the 1.5 - 2.0 don’t panic principle to all the modern valves.

Good luck with your personal INR control.
 

pellicle

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However, this trial tells me that there is no reason to panic (for example, get a low molecular weight heparin injection) if INR temporarily drops between 1.5 - 2.0.

I don’t see a huge difference between modern bileaflet pyrolytic carbon valves so I think that it is reasonable to extend the 1.5 - 2.0 don’t panic principle to all the modern valves.
this is the position I adopt too ... and fed into (along with other evidence) my approach here:
http://cjeastwd.blogspot.com/2017/12/perioperative-management-of-inr.html
 

Protimenow

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According to a study by the Duke University Clinic, a clot can form on a mechanical valve, if INR is below 2.0, in about 10 days. I'm looking for the original of this study - it's hiding in one of these forums.

Although it may not be common that a person's INR would crash below 2.0 for no apparent reason, personally, I wouldn't want to risk the possibility of maintaining my INR (without knowing it) below 2.0 for any extended period of time.

Hell, if your INR is stable, why waste ANY strips, or test at all? I ran for more years than I care to admit, without testing - and had no negative episodes. I was careless and stupid.

I had a TIA when I WAS testing and managing my INR, because the meter told me 2.6, and the hospital said 1.7.

I don't think that weekly testing is a waste of a strip -- even if it only confirms that my INR has remained in range. I'd rather waste a strip a week than have another TIA.

And, as I've noted before, a low INR for a few days doesn't worry me - my normal dose of warfarin brought my INR back into range in three days - without Lovenox.

Still, Tom, regardless of what your unreferenced sources say, I'm still trying to keep my INR above 2.0 - preferably around 2.5 - as the published sources that I've cited, and Astro quoted - give as recommendations.
 

jlcsn2015

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I have an AV-Onx, and the PROACT study, gives the peace of mind that in case INR drops below 2, it should be fine, but i am always around 2.2 , the only additions is that On-X tells u to take 1 ASA 81 mg a day, which is no big deal, And as per those concerned about Warfarin, , i can only say that i have met many people 67+ that had NO heart surgery and are on Warfarin for other reasons...., so "for me", knowing my valve will out last me, and that i am already on warfarin is a bonus, "at my age", As per testing, in Spring-Summer i go to the LAB every 10 days, Fall-Winter i use Coagucheck, Canada weather related.
 
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