INR range for AVR with On-X

[T in YVR]

Hi,
Just curious - my INR was set by my surgeon to be 2.0-3.0. I had only my aortic valve done earlier this month. It was replaced with an On-X. They have me on Coumadin + 1 low dose aspirin daily. Are most other people in the 2-3 range for just AVR? My surgeon said they would have me at 2.5-3.5 only if I had another valve done like mitral.

My GP was a bit surprised by this and said that was a relatively new development to him. Most of his other patients were 2.5-3.5. Are they giving lower INR ranges for AVR only, or does it have to do with it being an On-X valve?

Tony

 

[Ola Thoresen]

I am in the 2-3 range, and some doctors are a bit surprised by this, so I guess the normal used to be slightly higher. But I try to avoid the lower part of the range, and stay between 2.5 and 3 anyway.

 

[pellicle]

the newer pyrolytic carbon valves (such as the On-X and the ATS) have reduced anti-coagulation needs. As far as I know the aspirin is for other therapeutic benefits rather than only coagulation issues.

I guess that most of your GP's other patients have older valves....

 

[dick0236]

I believe that the lower INR range is due to materials and technology of the newer valves. I have AVR only and my docs have always had me at 2.5-3-5 due to old valve design and materials. There, seemingly, is not a significant difference, in PT(clotting time) between 2-3(21-30 seconds) and 2.5-3.5(26-34 seconds).....some doctors seem to think so. Regardless of INR range, I believe most long time valve patients prefer the mid to higher end of their range. Personally, I do not get overly concerned with any INR between 2-4, although I do make dosing changes when I approach these limits.

 

[Protimenow]

I have only an Aortic Valve, too -- a St. Jude. The 'safe' zone for the On-X is, supposedly, 2-3. According to some research that I've seen, having an INR below 2.0 significantly increases the risk of clot (and stroke).
My concern is that the methods for testing aren't exact -- that a 2.0 in one lab (or on a meter) may be as low as 1.7 or as high as 2.3, and still be considered 2.0. If you're self-testing -- and I strongly urge you to do this - and you use an InRatio or a CoaguChek XS, although the XS is usually closer to lab results than the InRatio, both meters often report somewhat higher than the labs do. (The Coag-Sense, in my experience, is often slightly lower than the lab that I use).

If you're relying on your meter's accuracy, as I did last year, and accept an INR at or near the bottom of your range, it is possible that you'll be tempting fate because your actual INR may be below 2.0. Even if I had an On-X, personally, I would still shoot for 2.5-3.5 (or, to make your doctor happy, 2.0 - 3.0 - a really tight range) in order to avoid that still dangerous sub 2.0 area. Absolute reliance on a meter's accuracy - especially at the low end of the range - may be rather unwise.

It would be better to be VERY CONFIDENT that a reported 2.0 ACTUALLY IS AT LEAST 2.0 - even with an On-X valve. At least, this is the way that I see it.

 

[chaconne]

The latest results from the On-X PROACT trial:

http://aats.org/annualmeeting/Program-Books/2013/1.cgi

seem to show that it's safe to have INR in a range of 1.5-2.0 if you have an On-X aortic valve. My INR range is 2.5-3.5 because I had a mini stroke to my eye (Amaurosis Fugax) one week after my surgery and my INR was 2.2 at the time. Normally my cardio would have me in the 2-3 range. Like others, I prefer to keep my INR above 2.5 just to be safe.

 

[DanielB]

I was originally on a 2-3 range, but the coumadin mangers at my medical group must have an odd chart as they kept running me below 2.0,. So my cardio changed it to 2.5-3.0, which works well with their management methods and, now, if my level drops, it is between 2.0 -2.5 -- all good. He also told me that 2.5-3.5 was common not too long ago and echoed the information above about how the new valves can use the lower range.

 

[big_L]

Mayo put me at 2.0 -3.0. I have the St. Jude mechanical. My local "Coumadin Clinic" would prefer to see it 2.5-3.5. They upped my warfarin a bit this week after a 2.1 INR.

 

[Bina]

There are varying opinions on INR target ranges according to specific valve brand and location. My surgeon said 2.5--3.5 for my Regent in the aortic position.
My local hospital also recommends 2.5--3.5
I'm very confident that by keeping my INR around 3.0 my bases are covered. ( I don't have a history of internal bleeds or strokes.)

 

[Protimenow]

Repeating my concern: A 2.0 on a meter may be a 1.7 or 1.8 in a lab (I know this for certain, from personal experience). A 2.0 at one lab can also be a 1.7 or 1.8 at another lab. Even if the On-X IS safe in the range of 2.0-3.0, understanding that not all 2.0s are ACTUALLY 2.0 or slightly above, to me, it still seems to make more sense to aim slightly higher (maybe 2.4 - 3.4?). The difference in lifestyle with a 2.0 and that with a 2.5 is probably non-existent -- so there really isn't much that should weigh AGAINST shooting at a 2.0 target.

OTOH - the testing that was used for these studies may have been subject to the same variance that labs/meters exhibit, so it MIGHT be safe to stay near that minimum, even if the 2.0 that is called for is closer to 1.7 or 1.8.

 

[T in YVR]

Thanks everyone.

I agree with wanting to stay on the high side of the range. I can't wait to start home testing.

One major issue I have right now with the challenge of balancing your INR - especially at first - is how the doctors make recommendations on your Warfarin dosage. The protocol right now is that I get my blood drawn 2x per week (I am 3 weeks post op), and the doctor's office calls me later in the day to tell me what to take. So far my INR has been a bit of a yo yo since the surgery (as I heard it can be) - 1.2, 1.2, 1.5 (on Heparin in the hospital during this period), 2.2, 2.4, 2.2, 3.7, 2.8, 1.9. And they have adjusted the dosage - from 7.5 mg down to 5 (when I peaked) and then now alternating 5mg with 6 mg daily. But they make these decisions in a vacuum of sorts with no knowledge of how a person's diet is starting to re-establish itself back to normal post surgery. They get an INR reading and make a recommendation. I am starting to eat salads again etc. I keep thinking they're going to be wrong and I need to take more, but for now I have done what they have told me. I get tested tomorrow and am interested to see how it is affected. I can't wait to establish a more predictable pattern.

I had 2 questions:
1. Does anyone know how long you can go slightly out of range and be ok?
2. How long does it take for foods/drinks to affect your INR? Or is it a very individual thing based on metabolism etc? I have heard alcohol can be quite quick. Not sure about anything else.

Thanks again,
Tony

 

[pellicle]

I had 2 questions:
1. Does anyone know how long you can go slightly out of range and be ok?

As far as I know its a statistical thing as well as your "system". You could go weeks you could go days without problems. Certainly its unlikely to happen in the first day being under ... there were people on the ON-X trial as I recall reading with no events a year into "no anticoagulation"

2. How long does it take for foods/drinks to affect your INR? Or is it a very individual thing based on metabolism etc? I have heard alcohol can be quite quick. Not sure about anything else.

I personally can't understand the alcohol thing. I've also tested it myself and found that a bottle of red wine in an evening with friends (yes, I drank that amount) had no effect on my INR (measured the next morning), so if the effect is zero then its probably quite quick.

Anything with Vitamin K in it will do the trick (none in wine, spirits or beer as far as I know) and indeed Vitamin K is what is used to bring you back to coagulation fast in hospitals. Vitamin K has its source in our diets from plants. Plants use it in photosynthesis, so anything green is a candidate. I understand that broccoli has the highest levels of bioavailable Vit K (although I have personally tested Chlorophyll liquids and tablets and found no effect, so its NOT chlorophyll but is used in the same chemistry that chlorophyll is involved in as a co-factor)

My wife dug out a list at one stage, my view was that's too complex to remember, so I just go based on what part of the plant I'm eating.

If its green then its got some K in it ... the darker the green then as I understand it, the more it will have.

It isn't easy being green...

also, if your computer has an internet connection a really handy site is Google. I just typed in vitamin K food sources and got some links: this is the first 2, seem good to me.
http://www.healthaliciousness.com/articles/food-sources-of-vitamin-k.php
this one surprised me:
Chili Powder, Curry, Paprika, and Cayenne
vitamin K per 100g serving, or 8.5μg (11% DV) per tablespoon.

I'm unlikely to go that path for my Vitamin K

http://www.nlm.nih.gov/medlineplus/ency/article/002407.htm

 

[dick0236]

I had 2 questions:
1. Does anyone know how long you can go slightly out of range and be ok?
2. How long does it take for foods/drinks to affect your INR? Or is it a very individual thing based on metabolism etc? I have heard alcohol can be quite quick. Not sure about anything else.

Thanks again,
Tony

My range is 2.5-3.5. Any INR under 2 concerns me and I want it up ASAP. INRs above 4 are of less concern to me and I want them down, but more slowly is OK.

I think that INR management is personal to each patient as age, activity, diet, life style, etc all will play a part in INR levels.....however, it is not rocket science and as you get more active and farther away from surgery you will find your own keys to INR management. The major key is to relax and work towards staying anywhere within your range. You will occasionally get out of range, for no apparent reason, but that normally ain't a big deal.

 

[Protimenow]

As Pellicle already said, Vitamin K is used to quickly lower INR in patients whose INRs are way too high. Our bodies metabolize the green, leafy things pretty quickly.

As far as what can happen if our INRs are way out of range -- according to some research (possibly from the pre-OnX days), if your INR drops too low, you may be at risk of a stroke in a week or so. If it's above your range, this depends on HOW HIGH the INR actually is. For some reason, my INR has been up in the 4.0 range, and I've dropped my dosage, but found that I bruise a bit more easily now than I did when my INR was in range. However, with an INR considerably higher, there's an increased risk of internal bleeding (blood in urine, for example, or even worse (brain bleeds)). This is his warfarin is used to kill rodents that aren't already resistant to the effects of warfarin -- bascally, they just bleed to death internally.

So -- in brief - it's safest to stay in range. From my perspective, I still prefer to stay within 2.5-3.5. Being slightly out of range shouldn't be dangerous, but should be corrected sooner rather than later, but major dosage changes can cause other issues. (If your doctor is making 50% dosage changes, there may be real problems getting the INR into range -- smaller changes should make it easier to find te ACTUAL result of your current dosing, and not run into the changes that large modifications can create).

 

[tom in MO]

I take warfarin and baby aspirin. My aortic valve, St. Jude, is managed at 2-2.5. I was told it used to be 2-3, but has been adjusted. I think it's due to more data and the use of the baby aspirin. My cardio and coumadin clinic say that if my INR drops under 2, it's not a big deal. The valve I have is quite stable. To raise it, they use a single dose. If it stays low next time, they do a big dose and a little increase for the week. My dose does vary by day though (e.g. MWFS 5 mg, TThS 4 mg).

It took about 2 months for my INR to settle down. I was usually low too. I've been out of range low for up to three weeks with no problem and no worry on my doctor, nurse or cardio's part.

Per your team, they don't care about your diet, that's good. They are dosing you not your diet. Your diet will change in the future as well (e.g. you get sick, lettuce comes in season, etc.) and your INR will be adjusted. It's OK and normal.

 

[Protimenow]

If your St. Jude valve is recent, perhaps you're at less risk of clotting. For myself, trusting my meter's accuracy, and staying above 2.0 (according to the meter), I had a stroke. There aren't many (if any) negatives associated with maintaining an INR somewhat higher than 2.0, and there is STILL risk if you fall below that (perhaps if your valve is older than, say 10 years or so), so, for me, a 2.5-3.5 is still the optimal -- especially because many meters give higher than actual results.

FWIW--there was a period during my post-op times when my monitoring was very infrequent. I have no idea what my INR was. It's possible that my INR was below 2.0 for extended periods, too. I have no clue. It may be that 99% of the time, with an INR below 2.0, you're totally safe. It's that 1% of the time when you're below 2.0 that can kill you. Personally, I prefer to test weekly and to maintain my INR between 2.5 and 3.5 -- regardless what doctors are now saying. I know that, for me, trusting a 2.0 (or, in some cases as high as 2.6) on my meters created a situation that caused me to throw a clot.

 

[tom in MO]

My St. Jude is a recent implant but of a well-established model.

Per my cardio, the range changed from valve model introduction (2-3 IIRC) to the current recommendation of 2-2.5 based upon historical data and possibly the use of low-dose asprin. My surgeon, cardio and coumadin clinic doctor were all asked by me to weigh in on the range 2-2.5 and they all agreed it was appropriate but a new range. In addition, they all have stated low INR excursions are not a danger for my valve type in the aortic position and not to sweat an INR less than 2. ALthough not directly stated, they implied that being less than 2 is a bigger problem for other mechanical valves and in other valve locations.

 

[chalee94]

I take warfarin and baby aspirin. My aortic valve, St. Jude, is managed at 2-2.5.

i got an on-x 2 months ago and am targeted for the same range. (and am on the same warfarin and baby aspirin regimen.)

i've gotten a 1.8 reading a few times as i've been adjusting to the warfarin but this board is making me more comfortable with aiming around 2.5.

(i definitely like the idea of getting my own home tester but i've been told it'll take over a year...)

 

[Agian]

For myself, trusting my meter's accuracy, and staying above 2.0 (according to the meter), I had a stroke.

Was it later verified that you were actually below 2, despite what your meter said? I think your point is very important.

 

[Protimenow]

Yes. Immediately after the stroke symptoms, I took two aspirin (because I suspected that I may have had a stroke), and tested my blood with my 'trusted' meter. The INR was 2.6. My blood draw in the hospital the next day was 1.7. The following day, it was 1.8. I didn't do anything between the time that I got a 2.6 and the time that the hospital tested my blood that would have caused the INR to drop...if anything, I would have wanted it to be a bit higher.

The meter that I was using -- and trusting -- was an InRatio. It's been replaced with an InRatio 2, but even though I have probably 60 or more strips for it, I'm not using it for testing (although there's a formula that can be applied to its results that can be more predictive of actual lab results). Instead, my primary meter is a Coag-Sense, and I often also test with a CoaguChek XS. The Coag-Sense usually reports somewhat lower than the labs (which means that a 2.0 on this meter may be more like a 2.1 - 2.5 in a lab test, and puts me where I want to be), and the CoaguChek XS is usually slightly higher than the labs. The labs usually come out somewhere midway between the two.

Yes -- the labs DID verify that, contrary to what my meter was telling me, my INR WAS below 2.0.