The likelihood of a stroke in AVR patients vs. the regular population...?

[T in YVR]

A couple days ago we had a tragic event occur in our office where I work. A woman (around age 50) had what turned out to be a fatal stoke. Found unconscious, (probably had been so for about 10 min), rushed to emergency, remained in a coma for 1 week in ICU, and very sadly passed away the other day. It obviously hit alot of people very hard and is tragic when this kind of thing happens.

It got me to thinking/reflecting (as I turn 50 this year) - *generally* speaking (since everyone is unique in their own situation), is the likelihood of a stroke actually much less in many of us - esp. those with mechanical valves - who have had AVR than it is for the general population? I mean, many of us have mechanical valves, are on warfarin and monitor our INR very regularly (I home test weekly) - and our INR range is obviously higher than the general public (2-3 or 2.5-3.5 vs. ~1.0), to help prevent clots from forming in and around our valve. But this higher INR level should reduce the likelihood of clots forming anywhere in our bodies. Right? With many people in the general public, they have no idea what their INR is, and less likelihood of knowing if a potentially fatal problem lurks unless you are very proactive about your own health, get regular blood work and check ups etc - and even that can only tell you part of the picture.

Anyways, I was just curious about people's perspectives on this....this sad event got me to thinking about life and the likelihood of strokes etc. So many variable at play I guess (smoking, diet etc), but all things being equal, I have to think that an AVR patient has some reduced risks due to the monitoring and warfarin (generally if mechanical), and even the recommended emphasis on a healthy lifestyle and diet as a result of open heart surgery/AVR.

Thxs,
Tony

 

[MethodAir]

So many variable at play I guess (smoking, diet etc), but all things being equal, I have to think that an AVR patient has some reduced risks due to the monitoring and warfarin (generally if mechanical), and even the recommended emphasis on a healthy lifestyle and diet as a result of open heart surgery/AVR.

I was thinking the same thing myself recently.

 

[Paleowoman]

There are two types of stroke though, ischaemic stroke which is the one caused by a blood clot, and haemorrhagic stroke which is caused by a weakened blood vessel bursting. Even children can get strokes, rare though. If we live our lives as healthily as possible I'm sure that helps avoid strokes, and many other illnesses. It's always very shocking when a younger person suddenly dies, makes us think of our mortaily all the more.

 

[pellicle]

Hi

... is the likelihood of a stroke actually much less in many of us - esp. those with mechanical valves - who have had AVR than it is for the general population?

To my understanding yes ... but only those of us valvers who are on AC therapy.

It will also depend which valve you're on too. I've read (and have some small experience) that the tilting disk valves (not the modern bileaflet valves) do cause clots despite AC therapy. I understood that the current views on that (now ancient technology) are that its caused to repeated damage to the components on their flow through the system and eventually trigger platelet clumps. So the cause is platelet aggregation not thrombosis as far as I understand that specific case.

From what I understand in my readings well anticoagulation monitored patients have no significant change in stroke or bleeds to the general population rates. So despite technically higher provocations well regulated AC therapy is not a substantial risk.

 

[rakesh1167]

I think it is no. We have artificial valves that could throw clots where as general population don't. This is the reason we are recommended AC therapy and they are not.
Even after AC therapy we have more than 1% chance of a stroke(including minor strokes) per year. Verified this in many research articles. If this was applicable to general population we would be having 3 million strokes per year in America and more than 10 million in India.

 

[[email protected]]

A couple days ago we had a tragic event occur in our office where I work. A woman (around age 50) had what turned out to be a fatal stoke. Found unconscious, (probably had been so for about 10 min), rushed to emergency, remained in a coma for 1 week in ICU, and very sadly passed away the other day. It obviously hit alot of people very hard and is tragic when this kind of thing happens.

It got me to thinking/reflecting (as I turn 50 this year) - *generally* speaking (since everyone is unique in their own situation), is the likelihood of a stroke actually much less in many of us - esp. those with mechanical valves - who have had AVR than it is for the general population? I mean, many of us have mechanical valves, are on warfarin and monitor our INR very regularly (I home test weekly) - and our INR range is obviously higher than the general public (2-3 or 2.5-3.5 vs. ~1.0), to help prevent clots from forming in and around our valve. But this higher INR level should reduce the likelihood of clots forming anywhere in our bodies. Right? With many people in the general public, they have no idea what their INR is, and less likelihood of knowing if a potentially fatal problem lurks unless you are very proactive about your own health, get regular blood work and check ups etc - and even that can only tell you part of the picture.

Anyways, I was just curious about people's perspectives on this....this sad event got me to thinking about life and the likelihood of strokes etc. So many variable at play I guess (smoking, diet etc), but all things being equal, I have to think that an AVR patient has some reduced risks due to the monitoring and warfarin (generally if mechanical), and even the recommended emphasis on a healthy lifestyle and diet as a result of open heart surgery/AVR.

Thxs,
Tony

Hello, my name is alan, I will be having a on-x valve replacement June 13. I am a rnfa in surgery. I would have to agree with you. When you are in tune with your body and keeping the blood thin, I think we would be at a lesser risk of stroke.

 

[dick0236]

Logic tells me that ACT should work in helping to dissolve clots or prevent internal bleeds.........but ONLY if ACT is maintained within a prescribed range. If you "play fast and loose" with managing ACT you can, and probably will, suffer a stroke like consequence..........been there, done that . Misused warfarin will cause as many problems as it prevents.

 

[JulienDu]

According to this study : http://www.ncbi.nlm.nih.gov/pubmed/17890730 (over 1346 patients)

"The incidence of thrombo-embolic events that required hospital admission was 0.37 and 0.19% per patient year in the conventional and low-dose groups, respectively (P = 0.79)"

 

[pellicle]

Hi

I think it is no. ...Even after AC therapy we have more than 1% chance of a stroke(including minor strokes) per year. Verified this in many research articles. I.

I think your logic is sound except for the point "well regulated" AC therapy. You cite "the many research articles" and I will say that those are usually on what I would classify as poorly regulated plus are not (and they never are) restricted to valvers. They include every dippy and muddled head elderly fuddy who can barely remember what day it is let alone did you take your pill today. This is mentioned in some studies and is something that the pharmacists I've spoken with regularly lament (their elderly patients dippiness).

 

[T in YVR]

Logic tells me that ACT should work in helping to dissolve clots or prevent internal bleeds.........but ONLY if ACT is maintained within a prescribed range. If you "play fast and loose" with managing ACT you can, and probably will, suffer a stroke like consequence..........been there, done that . Misused warfarin will cause as many problems as it prevents.

I agree with you Dick. I have to believe that the likelihood of a stroke, when ACT is managed correctly and very proactively, is perhaps lower in mechanical valvers. We're running at a higher INR than would normally be the case in a healthy individual with no heart problems and no ACT....

 

[yotphix]

Any statistics on stroke probability in ACT patients will also be polluted by the inclusion of the general ACT populace, who at least one study has shown to be in range not more than 50 percent of the time. People managing their own ACT, or taking a more active role in it in cooperation with their doctors are in range well more than that. (I forget the numbers I've seen just now, but 75 or 80 per cent is what I dimly recall).
When I presented at emergency a couple of years ago with numbness in the left side of my face and tongue, they feared it was a stroke at first, but then ran a PT test, found that I was in range, and got comfortable with the idea that they were seeing a version of complex migraine. The attending physician actually said 'with you anti coagulated, and in range, a stroke is really improbable. Not that his opinion is gospel, but it does make sense.

 

[rnff2]

As a nurse and now a valve replacement patient on anticoagulants I feel that we, valve replacement patients on anticoagulants are at a higher risk for stroke. Being anticoagulated increases our risk for a hemorrhagic stroke. I also believe being well controlled and knowing your INR does help reduce this risk. Having a mechanical valve increases our risk for blood clots thus increasing our risk for ischemic strokes. Again having a well controlled INR will reduce this risk, but there is still a risk. I also believe that we are able to reduce our own risk of stroke because of the knowledge and the awareness that we have gained due to being a valver on anticoagulants. Just my personal thoughts on the subject.

 

[pellicle]

The incidence of stroke in the general population may not be as well understood as is presumed:

http://www.ncbi.nlm.nih.gov/pubmed/17030827

I'm of the view that brain bleeds are different to clots and so consider them differently (as does much of the literature). My view is that being on well managed INR can not make you more likely to have a stroke but may make you more likely for an IC bleed or at the least worsen its outcome.

Its a moot point though because we're on AC therapy for good reasons and we don't really have the choice to go off.

Then from the GELIA study:

Conclusions: The intention-to-treat analysis of the results of the German Experience With Low Intensity Anticoagulation study leads to the unexpected result that despite a sophisticated reporting system, the incidence of moderate and severe TE and bleeding complications was comparably low in all INR strata and more or less within the so-called background incidence reported for an age-related “normal” population. This study supports reexamination of the intensity of anticoagulation in patients with the SJM valve.

which is the study I was thinking of when I wrote the above:

...From what I understand in my readings well anticoagulation monitored patients have no significant change in stroke or bleeds to the general population rates. So despite technically higher provocations well regulated AC therapy is not a substantial risk.

Lastly from Recommendations for the management of patients after heart valve surgery

Recommendations
It should be recognized that TE after valve surgery is multifactoral both in its aetiology and in its origin.9
Although many TE events will have originated from thrombus or a vegetation on a prosthesis or as a
result of the abnormal flow conditions created by a prosthesis, many others will have arisen from other
sources as a result of other pathogenetic mechanisms and be part of the background incidence of
stroke and TIA in the general population. This underlines the importance of thorough investigation of each
episode of TE, rather than simply increasing the target INR or adding an antiplatelet agent.

 

[Paleowoman]

I'm of the view that brain bleeds are different to clots and so consider them differently (as does much of the literature).

They are different but they are both called "stroke": "haemorrhagic stroke" and "ischaemic stroke" but they are both referred to as "stroke" which is unfortunate as they each have a different cause. "Ischaemic stroke" is the clot stroke and "haemorrhagic stroke" is the brain bleeding stroke.

 

[rnff2]

I agree that brain bleeds and clots are very different and really fairly opposite when it comes to the cause and the treatment. It's the injury they cause to the brain itself and long term treatment of that brain injury that makes them somewhat the same.
Interesting, now that I think more about it.

 

[T in YVR]

When I made the original post, I wasn't very clear, but I was referring mainly to Ischemic strokes (clots)...I would expect internal bleeding / haemorrhagic would certainly be higher or pose greater risk in AC patients.

 

[pellicle]

Hi

When I made the original post, I wasn't very clear, but I was referring mainly to Ischemic strokes (clots)....

so I guess that you'd feel more comfortable now.

A quick point, as far as I know its actually not correct that being on warfarin dissolves clots. As far as I know they are broken down by the body using such therapy. Tissue Plasminogen Activator on the other hand does actively break clots and (as I mentioned in a recent post to a fellow in NZ) is the gold standard (not just ramping up AC therapy.

http://www.strokeassociation.org/STR...p#.Vxv0K3F9600

tPA, the Gold Standard The only FDA approved treatment for ischemic strokes is tissue plasminogen activator (tPA, also known as IV rtPA, given through an IV in the arm). tPA works by dissolving the clot and improving blood flow to the part of the brain being deprived of blood flow. If administered within 3 hours(and up to 4.5 hours in certain eligible patients), tPA may improve the chances of recovering from a stroke. A significant number of stroke victims don’t get to the hospital in time for tPA treatment; this is why it’s so important to identify a stroke immediately.

as I always say its dangerous to keep using simplifications such as "blood thinners" because AC therapy in no way acts to thin the blood or like a pain thinner as a solvent. People die because of "shortcuts of speech" like this and you find some poor bastard has had their INR whacked up to 5 to "dissolve a clot"

 

[T in YVR]

Hi

A quick point, as far as I know its actually not correct that being on warfarin dissolves clots. "

I was thinking that being on warfarin played a role in helping to reduce the likelihood of clots forming vs. dissolving them.
T

 

[pellicle]

I was thinking that being on warfarin played a role in helping to reduce the likelihood of clots forming vs. dissolving them.
T

that is what I assumed and that is why I answered yes in my first post ... you will recall that you initially asked "...is the likelihood of a stroke actually much less in many of us - esp. those with mechanical valves - who have had AVR than it is for the general population?"

to which I replied YES. I suspected you thought I was saying the opposite when you replied to Dick.

And I put in the extra information about disolving them because of other things said (not anything you said).