Stroke Risk With Various Types Of Valves

[Guest]

The Annals of Thoracic Surgery (2004;78:77-83) has an article about the risks of stroke after valve replacement. The study was done by Ruel et al in Canada. They studied 3,189 adults with various types of valves for a total of 20,096 patient-years. This is a big study over a long period of time so the results should be pretty valid. Here are the stroke rates and some other bits of information.

Site Type Stroke Rate
Aortic Bioprosthetic 1.3% per year
Aortic Mechanical 1.4% per year
Mitral Bioprosthetic 1.3% per year
Mitral Mechanical 2.3% per year

Those who had two valves were not at greater risk for stroke.

Taking aspirin or dipyridamole in addition to warfarin did not lower the stroke risk.

It does not appear that they were able to include information about whether the people kept their INR in range or not. Presumably this is everybody lumped together. Some would have tight control of the INRs, some probably skipped considerable doses of warfarin and there were even times when people were off warfarin. This is a look at real-people in the real-world averages.

 

[tobagotwo]

Very interesting study, and thank you for sharing it. You bring fascinating reading to the site all the time.

To add to what you were saying about lumping things in, it's also noteworthy that age ranges are not separated, and that it doesn't separate by other information, like how many also had bypass issues.

Still fascinating. I wonder what the rates for "normals" would be in comparison, if we were able to deduce a general age range?

 

[catwoman]

A question

A question

Al:

Any thoughts on why the risk is greater with a mechanical mitral valve than with a mechanical aortic valve?

 

[Karlynn]

Al:

Any thoughts on why the risk is greater with a mechanical mitral valve than with a mechanical aortic valve?

Because we mitral valvers try harder!

 

[tobagotwo]

I don't know (maybe Al does) what the average age is for valvers, but I would suspect that it is up there enough that a good percentage of the strokes shown may not be statistically associable with the valve. Maybe a quarter, or a half, or three quarters could be more age-associated than valve-associated. The age distribution might be relatively equivalent between types, but there would be an addition factor in the numbers from age-related statistics.

What I'm saying is that the numbers you see there probably do not accurately reflect your own risk, but are more interesting in terms of their comparisons to each other as relative risks (minus a constant for age bias).

Also, do the criteria for stroke also include hemorrhages in the brain, or is that unclear from the study notes?


Thank you,

 

[Guest]

The blood is more sluggish at the mitral valve, so the risk of clotting is higher.

I think that the study only looked at clot-type strokes.

 

[tommy]

So Al, how does exercise change the risk.

When I'm pumping 150+ BPM for several hours, I guess my risk of stroke is pretty small. But what about the resting rate of ~50 while I'm sleeping?

 

[Guest]

That is why you take warfarin.

 

[Harpoon]

But ummm.... What about us folks with artificial tricuspid valves???


Don't we count for anything?


It would be interesting to see a comprehensive study on all kinds of valve replacements and such, though at some point a lot of the individual circumstances can get to a point where a "comprehensive" (and valid) study can't be done.


How many folks out there have mitral valves in the tricuspid position (like mine?) How many of those have associated heart conditions that go beyond what you would see in someone with an incompetent valve (or even CHD's which inherently predate the artificial valve?)

Anyways, I guess it doesn't really matter. Majority rules eh?


I'll just sit here and piddle away as possibly one of only a handful or so of folks with simple TGV, a mustard, and an artificial tricuspid at 30 y/r with no other (current) complications short of intermittent bouts of pure insanity....


I'll shut up now.