Mechanical valves cause neurological problems?

[brendamarlene]

Has anyone heard of mechanical valves causing neurological problems? I just read this posting elsewhere on the internet...

"that mechanical valves can cause neurological damage in that they tend to cause the formation of small thrombi-emboli. These very small clots travel to the brain and can cause problems with memory and other neurological deficits. "

 

[Ross]

If not anticoagulated, yes they can and in extreme cases, even if anticoagulated it's possible, but highly unlikely.

 

[AmyCe]

mechanical valves and heart problems

mechanical valves and heart problems

My grandmother had her mechanical valve for 26 years before she died of bladder cancer. She was sharp until a week before her death. She was 89. No neurological problems whatsoever.

 

[tobagotwo]

I agree with Ross, inthat the purpose of anticoagulation therapy (ACT) with Coumadin (warfarin) is to prevent that very thing from happening.

Statistics seem to bear out that warfarin is effective in preventing this. There is only a minute difference in thrombosis (blood clot) rates between mechanical and biological valves. Moreover, some of the newer mechanical valves have been improved to be even less prone to the creation of emboli.

There have been discussions of the formation of microemboli in the disturbed bloodflows created by most replacement valves, and most frequently in the mechanical valves, but the results seem to fall short of providing convincing evidence of actual damage from them, except in rare cases.

I don't recall if there was a check made against normal native valves, to see if it is something that everyone lives with. However, one would have to think that a badly calcified native valve would produce a significantly disturbed bloodflow, and consequently also likely produces microemboli before it gets replaced.

Dirk chased much information about the microembolism topic: http://www.valvereplacement.com/forums/showthread.php?t=8507

Best wishes,

 

[Buzz Lanning]

Clots

Clots

I've always had a difficult time understanding how clots form on, or around, the mechanical valve. The leaflets are always moving, plus when the valve is open, it would seem the high velocity blood flow (thru the valve) would prevent clots from forming around the valve annulus.

Anyway, it's hard for me to understand how clots can form in this type of environment, but unfortunately, they can . . .

 

[John & Joann]

The valves are a foreign body in the blood stream. The characteristics of the blood is to clot around the foreign body. Coumadin GREATLY reduces the chance of this happening. The smallest blood vessels are in the eyes. It is not unusual to have a small flick form in the small eye blood vessels. This will cause you to loose a SMALL amount of vision in the retina. Often this will be adsorbed back into the blood and the vision will return.

Joann has been there/done that many years ago. The vision did return 99.999% This occurence can be observed by dialating the eyes.

 

[Rush20]

I've always had a difficult time understanding how clots form on, or around, the mechanical valve. The leaflets are always moving, plus when the valve is open, it would seem the high velocity blood flow (thru the valve) would prevent clots from forming around the valve annulus.

Anyway, it's hard for me to understand how clots can form in this type of environment, but unfortunately, they can . . .

That's how my surgeon described it as well. He said the aortic valve is similar to a toilet with blood flow, meaning it's very unlikely any blood would actually clot on the valve due to the high rate of blood flow. However, the coumadin further decreases the odds.

...maybe he was just trying to make me feel better.

 

[tobagotwo]

With due respect to your physician's intentions...

Do not believe for a minute that it's safe to have a mechanical valve without Anticoagulation Therapy (ACT). Yes, some few people do get away with it, sometimes even for years, but the odds are poor, and the price is often tragic.

Blood clots can form because despite all the movement and bloodflow, there are eddies in the current, just as you'll find on the wildest river. In those eddies, the blood can congregate on the foreign surfaces.

That being said, with warfarin ACT, mechanical valves are fully serviceable, and have provided many untroubled years for many valvers.

Best wishes,

 

[bvdr]

The valves are a foreign body in the blood stream. The characteristics of the blood is to clot around the foreign body. Coumadin GREATLY reduces the chance of this happening. The smallest blood vessels are in the eyes. It is not unusual to have a small flick form in the small eye blood vessels. This will cause you to loose a SMALL amount of vision in the retina. Often this will be adsorbed back into the blood and the vision will return.

Joann has been there/done that many years ago. The vision did return 99.999% This occurrence can be observed by dilating the eyes.

I had my routine eye exam yesterday. During the exam they took photos of the inside of my eyes to examine part of the retina, get a really good look at the blood vessels as well as check for macular degeneration. No problems noted whatsoever. My blood vessels show no signs of problems despite having had hypertension for over twenty years. I doubt that I have missed more than three or four pills in all those years unless, of course, that they were ordered held for surgery or whatever.

During the exam we talked about "ocular migraines" and micro-emboli as related to valve issues. My eyes are in very good shape and no evidence that these "acephalic"migraines (new term .....used when ocular migraines are accompanied by symptoms other than in the head... such as numbness in a hand) damaged my eyes in any way.

The photos were very interesting to look at on the computer screen and he zoomed into a particular area and pointed out how to tell the difference between the veins and arteries and what he watches for in the areas they cross over each other. The photos are not covered by most insurance companies but added less than $20.00 to the entire exam.

All mechanical valves have some degree of turbulence. I know I have read that the side "jets" of turbulence are sometimes referred to as "washing jets" because they have the effect of squirting off the areas to the sides where little clots are known to grow.

Someone raised the question about diseased natural valves also creating turbulence and eddys that would also raise the risk of clots forming. That is very true. I was put on coumadin prior to my mitral valve replacement for two reasons. The first was the mitral stenosis itself created flow problems and the second was the paroxysmal atrial fib which creates it's own set of problems and increases the risk of clotting.

All mechanical valves require ACT.

 

[Dirk]

Dear Brendamarlene,

Bob already posted the link on the search I made on this topic.

For me the situation is unclear.

I started a correspondence with some neurologists who published these results. Those which first discovered the microembolies (so called HITS, high intensity transient signals) are today no more sure whether they have any clinical impact. It is clear that the HITS do exist and that they are ONLY produced by mechanical valves, where bileaflet valves produce much more than tilting disc valves if the latter ones are implanted in the right direction.
It is also clear that the HITS counts are not influenced by anticoagulation, so they also appear at patients with mechanical valves and optimal INR.
Most neurologists and heart surgeons think that - although the HITS do exist, they do not a damage to the brain.

Some few surgeons still think that these HITS only make slight damage to the brain in therms of cognitive abilities which can only be observed after a long time period.
http://www.ncbi.nlm.nih.gov/entrez/...ve&db=pubmed&dopt=Abstract&list_uids=12493511


One quesiton to you: Where did you find the following text:
(I am interested to get to that werb site)
"that mechanical valves can cause neurological damage in that they tend to cause the formation of small thrombi-emboli. These very small clots travel to the brain and can cause problems with memory and other neurological deficits. "

Greetings


Dirk
__________________

 

[Dirk]

However, one would have to think that a badly calcified native valve would produce a significantly disturbed bloodflow, and consequently also likely produces microemboli before it gets replaced.

,

Bob

I was considering that too, and I got measured my HITS rate with my extremely calcified valve. I thought, o.k, if it would show up that I already have significant HITS and I feel well with them, a mechanical valve with a probably even lower rate would be fine.
But damnn... they did not find any HIT with me.

Greetings


Dirk

 

[tobagotwo]

I had an incredibly in-depth eye exam for Lasik a couple of weeks ago, and they found no evidence of any mircoemboli in my eyes. I was also curious, due to visual migraines.

So, I guess I trash the possible-microemboli-from-calcified-native-valve theory. At the very least, we have shown that it is not a given in that situation.

Of course, now I have no excuse for doing idiotic things...

Best wishes,

 

[ar bee]

with all due respect

with all due respect

the study used 30 males only, what significance does that have, please!!! I really dont know how the editors of this journal can accept studies with such a small sample!!!

well2allofu
ar bee

 

[gijanet]

Ok..............all of this scaring the hell out of me........

Ok..............all of this scaring the hell out of me........

As many of you know, Katie is having a mechanical valve "installed" as well as undergoing the extracardiac fontan in the very near future. A tissue valve is NOT an option for us due to the valve's location and Katie's complex combination of defects. Her surgeon prefers the carbomedics valve. I have tried reading some of the old threads and checked out some of the links, but I have to confess that "It is Greek to me." A little knowledge is a dangerous thing, and all of this talk is turning me into a basketcase again. I know that someone mentioned that these things could only be observed over a long period of time................well, we are looking at a lifetime here...........hopefully, thirty, forty, fifty years or so. Am I subjecting my daughter to a lifetime of visual disturbances, migraines, etc.? NOt much choice, I know, but does anyone know the effect that these HITS - or even coumadin, for that matter - have over an extended period of time on a still developing brain and body?

I know we really have no choice, but if there is a mechanical valve that shows fewer HITS incidents (logic?) and has a proven track record, then that is the one I want for Katie. If someone has time (yeah, I know, I know - fat chance!) to put all of this in simple English for me while we still have some time to play with, then I would be forever in your debt (might as well be generous here - I owe everyone else on God's green earth! ). Any overall general conclusions would be fine, if there are any. Any help or insight would be welcomed, too - just please put it in simple terms for me. Thanks as always. Janet

 

[Dirk]

Gijanet,

as I mentioned before, the relevance of HITS is unclear.

My understanding of the situation is that if you have a mechanical valve, there is a risk for the production of thromboses, which could get into the brain and induce vision problems and possbly much worse things like a stroke. If the anticoagulation is well maintained at the target INR, it has been shown that the risk for these problems is comparable to the risk of a healthy person. To obtain these good results it is recommended to use home testing for INR. In Germany, were I live, home testing is regarded to be mandatory for a mechanical valve.

The HITS are no thromboses. They are small gas bubbles generated at the valve leaflets during operation. Most surgeons and neurologists think that these bubbles are so small that they cannot damage the brain. However, few believe that there is a certain risk to effect cognitive function over a long time period.
It has to be taken into consideration, too, that any heart surgery itself generates a huge amount of these HITS. They are produced in the heart lung machine. Some assume that the cognitive deficits some persons experience after heart surgery might be due to the exposure by HITS during the operation.

For somebody to decide on the type of valve, it is not easy to take everything into consideration: First, at his surgery he will be exposed to a huge amount of HITS with some possible effects. If he got a mechanical valve, he will be exposed during the rest of his life with a low but constant rate with HITS generated by the valve. If he got a biological valve, there will be no HITS produced by that valve. However, he is facing at least a second surgery which will expose him a second time with a huge amount of HITS.

So if you consider the total amount of HITS travelling in your brain during your lifespan for both options, the decision is not easy. If you believe on possebly harm by HITS you will not defenitly know what would be the best strategy to minimise the HITS risks.

I know about one study which compares different valve types. In this study the ATS valve was that with the lowest amount of HITS. The other valve brands , St. Jude and Carbomedics, produced much more HITS. I can get into my files and search for the paper if you want me to do that.
The most less HITS produces the Medtronic Hall tilting disc valve (see the link I posted in the earlier reply within this thread). But this one might have other disadvantages (much more noisy).

Greetings

Dirk

 

[gijanet]

Dirk, thank you!

Dirk, thank you!

I appreciate your time and response. I have read the majority of the posts in this thread, as well as your last one, three or four times, and it is starting to make sense to me. Not ready to teach a class, by any means, but at least it is starting to look like English.

I have to confess that, just because I am starting to understand some of this, it doesn't make coming to a decision any easier. I have yet to pull up all of the links that you have researched and Twobagatwo (sp?) referenced. As I do so, I am sure that I will have more questions and hope that you will be around to pose them to.

THanks for all of your help. Hugs. Janet