Why do mechanical valves favor bllod clot formation?

[Midpack]

Hi!

Do you know why mechanical heart valves are prone to blood clot formation? Is it because the material is artificial and not biological? But, if that is the case, there are many other cases where artificial devices are implanted on the human body and anticoagulation is not necessary. For instance, to take a close cardiologic example, almost everyone having their mitral valve repaired have an artificial ring implanted (to give better support to the repaired valve). Why are not clots forming on this ring too? After all, this ring is as "strange" to the body as a mechanical valve...

Merry Christmas!

 

[Adrienne]

I think that the reason is that when the parts are NOT moving, they are eventually covered up by our own endothelial cells. Even people who have a MV repair have to take Coumadin the first few months (until the parts are covered). When talking about a valve, it's different because it moves all the time.

 

[pellicle]

Hi

Do you know why mechanical heart valves are prone to blood clot formation? Is it because the material is artificial and not biological?

as I understand it it is related to the platelets attaching to the surface. As well opening and closing 'jet' velocities can trigger platelet activation too. Actually this point is something which I recall advantaged ATS and On-X (however slightly) over St Jude.

Have a read of this document and look at some of the pictures

http://media.corporate-ir.net/media_files/irol/64/64106/ATS_Forcefield.pdf

quite interesting.

But, if that is the case, there are many other cases where artificial devices are implanted on the human body and anticoagulation is not necessary.

again, as I understand it, they are covered in materials by the body, not unlike what forms as pannus growth that eventually blocks valves. I think it is called epithelialization.