Why both Warfarin AND aspirin?

[Critter]

This is a quote from UpToDate. A source that I use everyday that I depend on to give me evidence based recommendations.

VKA plus aspirin better than VKA alone — Support for the addition of antiplatelet therapy to VKA therapy rather than anticoagulation alone in patients with mechanical valves comes from randomized trials. These results were summarized by two meta-analyses that each found that combined antiplatelet and anticoagulant therapy reduced the risk of mortality as well as the risk of thromboembolism as compared with anticoagulant therapy alone [2,20,21]. The latter of these found moderate-quality evidence that combined therapy versus anticoagulation alone significantly reduced the mortality rate (odds ratio [OR] 0.57, 95% CI 0.42-0.78) [2,20]. In addition, the analysis found high-quality evidence of significantly reduced thromboembolism (OR 0.43, 95% CI 0.32-0.59) and moderate-quality evidence of increased risk of major hemorrhage (OR 1.58, 95% CI 1.14-2.18) with combined therapy versus anticoagulant only therapy.

 

[vitdoc]

Like everything else there are trade offs. There might be a mildly reduced thromboembolism rate if antiplatelet agents are added to warfarin therapy.
It is not however a huge improvement certainly not 40%. On the downside that possible modest effect comes at a cost of increased bleeding.
The rate of thromboembolism is pretty low with warfarin especially if one tests and stays in the proper range. So aspirin is not typically routinely recommended as an additional therapy to standard warfarin treatment.
If however one goes to an INR of 1.5 as mentioned with the ON-X valve then maybe aspirin has a greater significance.
Remember many of the old warfarin trials and most of the recent trials were on people mostly not self testing.

 

[user 16827]

moderate-quality evidence of increased risk of major hemorrhage (OR 1.58, 95% CI 1.14-2.18) with combined therapy versus anticoagulant only therapy.

This is the reason one size does not fit all.

As @vitdoc correctly points out its a 'trade off' depending on the person's own situation.

 

[Critter]

Well for me; your mileage may vary, the addition of 81mg asa to my 1mg of warfarin is working great. Everyone is an individual lab experiment with their own nuances. So

 

[Critter]

That’s what’s recommended by my valve manufacturer and my physicians agree with it.

 

[cldlhd]

There are and the literature is not unanimously supporting it. I call it as a case by case thing. Why do you even need to involve a doctor? In Australia it's a supermarket purchase.

That's how I started taking it

 

[pellicle]

I don’t. I just need, as the title of the post makes clear, to know * why * we are often on both

I believe I covered the why in my first answer. I just asked a question (which you answered) based on your further discussion.

 

[catwoman]

Hi Catwoman.
in that this was your cardiologist’s reasoning, did both of your parents also have prosthetic valves? Was he comparing apples to apples?

Neither of my parents had any VR jobs. My dad died 1 month short of 87, my mother was 89 when she died. Neither took aspirin. My dad had right branch bundle block.

 

[ATHENS1964]

 

[carolinemc]

Neither of my parents had any VR jobs. My dad died 1 month short of 87, my mother was 89 when she died. Neither took aspirin. My dad had right branch bundle block.

So sorry for your losses. And many years ago they never did recommend the use of aspirin. Only in the last 30 to 40 years have they recommended and only at the discretion of the cardio.

 

[carolinemc]

View attachment 888128

And the source of this information, I would like to know and when.