INR - How low should you go?

[Chuck C]

I was curious on this as well as I recieved my ON-X back in June 2024. My surgeron gave me the 1.5-2 range in my consult but when I asked my Cardiologist he said I would be in the 2-3 range for life. When I inquired about the "marketed" range the surgeon gave me he said it was just that, marketing.

That is what my surgeon told me as well. In my pre-surgical consult, I was deciding between On-x and St Jude mechanical. He said he preferred the St Jude due to its long history and because it was less bulky- showed me a sample of each valve. He said the choice was mine and he's be happy to go with either valve. But, he said that if we go with the On-x, he will not have me on the low INR range, as that was just marketing. He said that he and his colleagues have major issues with the PROACT Trial, the small trial which was used to get approval for the lower INR range for On-x, and that it was dangerous to have INR that low. I ultimately went with St Jude.

I believe On-x is also a very good valve, but we have seen several members have clots at the lower INR range. If one reads the Proact Trial, this would be expected. Many more clots in the lower INR range, but because it was such a small sample size, it did not reach statistical significance. This allows them to say "no differences in the rates of TE and thrombosis events", which is not an accurate statement. There was a big difference, just not reaching a P value to achieve statistical significance. As @pellicle noted above TE and thrombosis was 2.96%/pt-yr in the test group versus 1.85%/pt-yr in the standard group, p = 0.178. This represents 60% more TE and thrombosis in the study group, verses the standard INR control group. This should have been a big red flag.

This low P value was almost certainly due to the small number of individuals in the study. Some might call this statistical slight of hand. Even though it did not have enough participants to reach statistical significance, the much higher rate of TE and thrombosis in the study suggests that there may be a major problem there which should have warranted further study, with more participants, before this low INR range was approved. Somehow Cryolife prevailed in getting the FDA to approve the low range without further study. Very questionable.

Other issues with the Proact Trial:

-The participants self tested. This has shown to reduce events drastically, by about 50%. Yet the low INR protocal was approved without requiring self testing. How was this overlooked?

-The low INR range was 1.5 to 2.0, but it would appear that they targeted closer to 2.0 for the study. The average INR for the low INR study group was 1.89. If the desire is to stay in a range consistent with the study, it probably should be more like 1.7 to 2.2 for patients to target. But, keep in mind, even at the 1.89 average INR range, they still had 60% more TE and Thrombosis events. So, I think that my surgeon had it right when he cautioned about the low INR range.

 

[Protimenow]

Yes, just marketing -- but marketing that could put people at potential risk of bad outcomes.

Somehow, I feel that my comments about not following the On-X guidelines was vindicated.

I'm also encouraged to know that there are SOME surgeons out there who actually read, and understand, studies related to their patients.

 

[pellicle]

Somehow, I feel that my comments about not following the On-X guidelines was vindicated

That's why I replied

 

[Protimenow]

Thanks

 

[Chuck C]

Thanks

No problem.

 

[pellicle]

Thanks

no problem

 

[Chuck C]

I'm also encouraged to know that there are SOME surgeons out there who actually read, and understand, studies related to their patients.

Yes. Some do. I'd like to say that most do, but sometimes it seems that most don't. I hope that is just an impression and not the reality. I'm fortunate that my cardiologist and surgeon stay up on the medical literature.

 

[Protimenow]

The impression that some have reported is that the physicians get an hour or two (maybe?) training in INR management, in Med School, and stop there.

From there, I suspect, they learn all they need to know from the device reps - like, for example, an INR of 1.5 - 2.0, plus 81 mg aspirin, is just fine for the ON-X valve, and it's extremely dangerous if, got forbid, an INR strays between 2 and 3.

I might be wrong. But, then again, I might be right.

(They probably leave dosing decisions to nurses in the office, to pharmacists at anticoagulation clinics, or to 30 year old dosing protocols).

 

[pellicle]

I'd like to say that most do, but sometimes it seems that most don't.

I feel the same way, but then I remind myself that on forums like this we have psychology similar to investment strategies and the identification of sources for bias. Here we often are exposed to the bad outcomes of surgery (people need to complain therefore something has gone wrong enough that they feel the need to be asking about that).

I think this biases our views. I hope this ...

 

[Protimenow]

I'm not sure how many negative results we get, and most of this is pretty positive.

We don't hear about the really bad results -- dead people aren't prone to complaining a lot.

 

[pellicle]

I'm not sure how many negative results we get, and most of this is pretty positive.

Enough from my perspective...

 

[carolinemc]

Yes. Some do. I'd like to say that most do, but sometimes it seems that most don't. I hope that is just an impression and not the reality. I'm fortunate that my cardiologist and surgeon stay up on the medical literature.

And I go to a teaching medical center. So, they are always on top of what the numbers should be.

 

[Mister_James]

Some questions should be on a pile of ridiculous questions - yes I said it. You can tell us you have maintained your On-X INR at 1.0 for 5 years and still going with a baby Aspirin once a month...SO WHAT?

Do whatever pleases you. Experiment...How low can you go? As low as you want and for as long as you can. How about that?

My neighbor has this huge cut out of DJT on his porch with a huge MAGA flag and every time we meet, he is explaining why he supports the man...and that he is not racist, or sexist...likes everyone...NO, NO...don't explain yourself to me. DO YOU.

 

[Protimenow]

When I was an undergrad at UCLA, Student Health was one of the benefits.

After seeing probably dozens of doctors by then (from childhood) and a LOT of doctors and students at UCLA Student Health Service, it took one student to hear (or be concerned about) my aortic murmur. None of the MDs caught it - or, maybe, didn't care enough to question it.

So - not all teaching medical centers are really on top of things -- in my case, it took a student with what I guess must have been a trained ear -- to catch my murmur.

Teaching hospitals might provide better care, but I'm not all that certain that they do, in many cases.

(OTOH - if you're at the hospital with a known medical condition, you might get better care because the students/doctors already know the protocols for handling your case.)