Aspirin in conjunction with Warfarin

[pellicle]

Thank you very much for the scientific knowledge you offer us.
A friend of mine used to say, <<For example, while stitching technique for sutures is an art learned through practice, the knowledge of what happens at the cellular and molecular level in the tissues being stitched arises through science.>>.
and today it happened and I read it here too
https://en.wikipedia.org/wiki/Medicine

I liked the wording of that Wikipedia entry, particularly this resonated

Medicine has been practiced since prehistoric times, and for most of this time it was an art (an area of skill and knowledge)​

​

I believe I have lived through the transition from more art than science to more science than art.

 

[Protimenow]

81mg Bayer aspirin is much more expensive than other "baby" asprin, at least in our neck of the woods, so my wife buys the lowest price aspirin, as long as it's enteric coated. My wife's target INR is 2.5-3.5 for mechanical AV and MV's and takes a baby aspirin daily.

I buy the 81 mg Enteric coated aspirin at Costco for about a penny each.

ALSO - personally I DO NOT modify my target INR because I take the 81 mg Aspirin. I would rather coagulate a bit more slowly than gamble with a reduction in my INR and risk having a stroke (I know - I had one because I had a bad meter tell me that my INR was 2.6 when it was actually 1.7).

 

[pellicle]

when it was actually 1.7).

you wouldn't be the first I've heard have a stroke on that INR

 

[Protimenow]

Our meters measure prothrombin time (the time it takes for a clot to form) AND INR. To calculate the INR, the clotting time is divided by a value for the reagent used to make the test.
Vitdoc - can we use the prothrombin time as a more accurate measure of our level of anticoagulation, because this would include the effects of aspirin?

Would this, perhaps, be a better measure than a calculated INR?

 

[Protimenow]

you wouldn't be the first I've heard have a stroke on that INR

No, I wouldn't. It may have been for the best, perhaps, because I took it on myself to test a wide variety of meters, comparing results to other meters and to lab tests. In my research, I also found that some labs were making significant errors.

My initial conclusion - that the Coag-Sense was the one that I had most confidence in - has dropped. Over the last few years, the results were USUALLY below lab results (by as much as a whole point), and almost always below the CoaguChek XS when the reported INR was above 3 or so.

I use the XS for most of my tests - it IS somewhat easier to use, it is widely used with few reports of problems because of inaccuracy, and is an overwhelming standard,.

 

[Unicusp]

No, I wouldn't. It may have been for the best, perhaps, because I took it on myself to test a wide variety of meters, comparing results to other meters and to lab tests. In my research, I also found that some labs were making significant errors.

My initial conclusion - that the Coag-Sense was the one that I had most confidence in - has dropped. Over the last few years, the results were USUALLY below lab results (by as much as a whole point), and almost always below the CoaguChek XS when the reported INR was above 3 or so.

I use the XS for most of my tests - it IS somewhat easier to use, it is widely used with few reports of problems because of inaccuracy, and is an overwhelming standard,.

So, in the above you state that Labs have made errors and you've experienced significant differences in results between the two meters. How do you conclude that the reading on the XS is correct and that the reading on the Coag-Sense is inaccurate? I'm curious because I rely upon the Coag-Sense. Thanks!

 

[Unicusp]

I buy the 81 mg Enteric coated aspirin at Costco for about a penny each.

ALSO - personally I DO NOT modify my target INR because I take the 81 mg Aspirin. I would rather coagulate a bit more slowly than gamble with a reduction in my INR and risk having a stroke (I know - I had one because I had a bad meter tell me that my INR was 2.6 when it was actually 1.7).

I have not seen it at Costco lately so I buy mine at Sam's Club. .006 per tablet.

Bayer is $18.99 for 400 tablets. Crazy. 8x more expensive for the same product.

 

[carolinemc]

I buy the 81 mg Enteric coated aspirin at Costco for about a penny each.

ALSO - personally I DO NOT modify my target INR because I take the 81 mg Aspirin. I would rather coagulate a bit more slowly than gamble with a reduction in my INR and risk having a stroke (I know - I had one because I had a bad meter tell me that my INR was 2.6 when it was actually 1.7).

I get a generic brand that is just fine for me. It is 81 mg and does not harm my INR.

 

[Protimenow]

So, in the above you state that Labs have made errors and you've experienced significant differences in results between the two meters. How do you conclude that the reading on the XS is correct and that the reading on the Coag-Sense is inaccurate? I'm curious because I rely upon the Coag-Sense. Thanks!

Years ago, I was convinced that the Coag-Sense was the most accurate. Its results seemed to be closer to the lab results than the CoaguChek XS. In many cases, I found the lab results to be close to an average of the results of the two meters.

I haven't done a lot of comparison testing in the last year or so, and the correlation with the labs was irregular - sometimes the Coag-Sense was closer, other times the CoaguChek XS was.

You asked how I determined which meter was correct - and I have to say that I don't know that either meter is 'correct.'

I'm leaning towards the XS for accuracy for a number of reasons:

Millions of people are using the XS (which in itself doesn't mean that it's necessarily right), but if there were significant errors near to 2.0, we would probably be seeing a number of strokes resulting from the meters overstating values. This hasn't occurred.

For self testing and at many (most?) INR clinics that use meters, the XS seems to be a standard (although I haven't done any extensive research to see if this is true). Again, complications that can be related to inaccurate results haven't been reported (or haven't been enough to get the attention of the FDA).

In my case, having an INR, as reported by my XSs (I have a few) is sometimes in the low 2s, there have been no bad events - although I still prefer to keep my INR in the 2.5-3.5 range.

I feel safe using the XS technology, a claim that I may have hesitated to make a few years ago.

 

[thomas999]

I just had my annual cardiologist appointment, and if I realized aspirin might be a good addition, I would have asked him about it. What would be the opinions in here to take the liberty and take aspirin without a cardiologist recommendation?

 

[Unicusp]

I just had my annual cardiologist appointment, and if I realized aspirin might be a good addition, I would have asked him about it. What would be the opinions in here to take the liberty and take aspirin without a cardiologist recommendation?

I don't know your age, but to me it's common knowledge that for one in his/her mid 50's or above, it is considered good practice to take. One 81mg enteric coated aspirin daily as a preventative measure. Of course if you are considered to be of normal health with no underlying conditions. I don't consider a mechanical valve to be in this category, just anatomical defect that's been corrected.
Or you can pay your Cardiologist a couple hundred $ for the same advice. Have not met one that did not agree.

 

[carolinemc]

I just had my annual cardiologist appointment, and if I realized aspirin might be a good addition, I would have asked him about it. What would be the opinions in here to take the liberty and take aspirin without a cardiologist recommendation?

Most cardio's will advise the use of aspirin. I was on the regiment at first 5 years, then was told to drop it. Got back on it back in 2018, due to a eye stroke. Been on it since. I am fine with it, and I have a St. Jude's aortic valve and on warfarin.

 

[dick0236]

I just had my annual cardiologist appointment, and if I realized aspirin might be a good addition, I would have asked him about it. What would be the opinions in here to take the liberty and take aspirin without a cardiologist recommendation?

I would ask my cardiologist before I started "baby aspirin" therapy.

 

[tom in MO]

I just had my annual cardiologist appointment, and if I realized aspirin might be a good addition, I would have asked him about it. What would be the opinions in here to take the liberty and take aspirin without a cardiologist recommendation?

If you are on warfarin, don't take aspirin unless it's part of your treatment therapy. My cardio says to call his nurse whenever I start a new medication.

 

[Protimenow]

I've been taking 81 mg enteric coated aspirin for years. I don't think it's enough to have much effect on my coagulation.

My cardiologist knows about this and hasn't said a word.

Also - FWIW - if you think you've had a stroke taking two Aspirin right away is supposed to help reduce the damage (but you STILL need to get to an E.R. ASAP).

 

[Unicusp]

Ironic, I was just reviewing my post surgical notes and findings from my surgery at the Cleveland Clinic (2 yr anniversary yesterday) and came upon this guidance regarding aspirin: - "Aspirin therapy: If you have undergone an coronary artery bypass surgery (CABG), ascending or thoracic aorta replacement, aortic valve replacement, aortic valve repair, or mitral valve repair: you should take Aspirin 81mg (one baby aspirin) daily lifelong."

 

[Protimenow]

Interesting advice from the Cleveland Clinic.

I've been taking 81 mg daily for years.

I had a bad fall two days ago, and a lot of muscle pain in my leg. I've taken 325 mg aspirin a couple times, and don't worry much about effects on my platelets. I'm not overusing it, and I skip the 81 mg aspirin.

I was told by a Rheumatologist that Ketoprofen - an NSAID - doesn't have much effect on platelets. I'll be trying that today. Ketoprofen might be an option when you need an NSAID and can't really take any other NSAID. I haven't looked into this, and don't know how minimal the effect is, but it might be an option.

 

[pellicle]

Cleveland Clinic (2 yr anniversary yesterday) and came upon this guidance regarding aspirin: - "Aspirin therapy: If you have undergone an coronary artery bypass surgery (CABG), ascending or thoracic aorta replacement, aortic valve replacement, aortic valve repair, or mitral valve repair: you should take Aspirin 81mg (one baby aspirin) daily lifelong."

I can see that as being beneficial. After all platelets are exactly part of thrombosis. I'm not going to advise you to stop, but what I did was ask my surgeon at about the 3 month mark about it and he said that the data showed it was not clear one way or another. He also said I could do what I wanted on that. So I stopped taking it.

Some 5 or so years later I experienced what I considered as being TIA's and so I wondered and decided to try re-taking aspirin but on a bit of a different regime. I take it every second day. Since I started taking it I haven't had those events. I went off it for a while and they came back so I have stuck with it since then.

If you have a mech valve then thrombogenesis from platelet activation (*caused by pressure jets on valve opening and closing) is cumulative and eventually (platelets have a half life is about 9 days ) a platelet is activated.

BTW this is not conjectural (as our favourite "citation free" arse clown here likes to suggest {Hi from Australia Tom}), from:

Comparison of the Hemodynamic and Thrombogenic Performance of Two Bileaflet Mechanical Heart Valves Using a CFD/FSI Model

Platelet stress accumulation during forward flow indicated that no platelets​

experienced a stress accumulation higher than 35 dyne's/cm2, the threshold for platelet activation (Hellums criterion). However, during the regurgitation flow phase, 0.81% of the platelets in the SJM valve experienced a stress accumulation higher than 35 dynes/cm2, compared with 0.63% for the ATS valve...​

DOI: 10.1115/1.2746378

So I guess experiment is your best way to find out.

HTH

 

[chebag]

I'm a 31 year-old with a On-X valve, a history of endocarditis (I say a history, but I've just had it once), and a target INR range of 1.5-2 (I know, I know).

I'm very active, and the cardiologist absolutely insists on the baby aspirin daily. I think if I didn't take the aspirin the INR range of 1.5-2 would probably be untenable, but what do I know. Valve is about 18 months old at this point, never had any TIAs or anything.

 

[Protimenow]

If I recall correctly, On-X promoted their valve, saying that those with the valve can have INR as low as 1.5 as long as they also take aspirin.

Personally, I wouldn't bet my life on that claim - I would have a target of 2.5 or so, just to stay safe.

On-X seems to imply that something terrible happens to people with INRs above 2.0 or so. Many doctors believe it.

I think that most, if not all, of the mechanical valvers here (with a few notable, argumentative, know it all dissenters) maintain INRs with targets around 2.5. Some On-X users are comfortable with the slightly higher INRs.

For us non On-X users, who maintain higher INRs (above 2.0), anticoagulation imposes very few limits on our activities or lives. Personally, I am MUCH more comfortable with an INR that's a bit on the high side than I am with one that 'tickles' 2.0. I had a TIA about a decade ago because I trusted a meter that was telling me my INR was 2.6 - in the hospital, it was 1.7.

Although I'm trusting my CoaguChek meters with my life, I STILL don't want my INR to be below 2.1 or 2.2.

I realize that the argument that On-X needs an INR of 1.5, plus 81 mg aspirin, if it was me, I wouldn't bet my life on it.