Regurgitation on a narrowing tissue valve???

[Debrinha GT]

I've seen so many threads where people have written about mitral valve regurgitation with or without symptoms, but up to now I had never stopped to think of how it really starts?? I mean, what actually causes a valve to start leaking? I've had three mitral valve replacements so far and all of them tissue. The last one was changed ten years ago but it has been slowly narrowing for two now. It's a Pericardium bovine bioprosthetic cardioprothesis valve No 29. Does the number of a valve have anything to do with when a person will need surgery again? I'm definitely going to need it once it gets to about 1,00cm2 and the last echo I got last October showed that it was then opening to 2,00cm2, maximum GRAD=14mmhg and medium GRAD=06mmhg. I went to see the cardio again last week and had an EKG. He said I'm doing ok and there's no trace of regurgitation. I'm going to fly from Brazil to New Zealand at the end of April and the cardio said I'm fit to go. Ten years ago my husband and I had tickets to go to Scotland to visit his family and just over a month before the trip I was taken by surprise by the news that I could no longer go on a plane because there had been a sudden rupture on my valve which was nearly 16 years old at the time and it was a dura-mater valve. So, here is the typical case of "Once bitten, twice shy". I've read that one of the reasons they stopped making them was exactly that. My surgeon told me just over a year ago that it's highly unlikely for it to happen again now and I should still have a couple of years left with this one.
Well, sorry my post was so long, but when I ask a question, I like to give you as much information as possible to help you with the answer. Any comments would be appreciated!??????? Thanks in advance!!!!
Débora

 

[tobagotwo]

Mitral Regurgitation

Mitral Regurgitation

Leakage from the mitral valve is referred to as mitral regurgitation (MR for short), mitral insufficiency, or even mitral incompetence. The most common cause for a mitral valve to start leaking is the same as for an aortic valve: calcium deposits start to build up on the valve's edges, which keep the valve from closing tightly. Another shared cause can be erosion of the valve leaflets from endocarditis.

However, the architecture of the mitral valve allows some other causations that the aortic valve doesn't have. When the left atrium pumps blood into the ventricle through the mitral valve, the pressure easily pushes the valve open from the atrium side. When the atrial squeeze stops and the ventricle begins to squeeze, the valve is pushed rudely shut by the pressure in the ventricle.

The action that brings the mitral valve leaflets together when they close involves chordae, which operate essentially like the cords on a multi-canopied parachute. The chordae may thicken and shorten, often unevenly, due to rheumatic fever, endocarditis, or from the repetitive strain of anchoring a prolapsed valve. This can cause them to hold the "parachute canopies" (valve leaflets) back from closing together properly. Individual chordae can also stretch or break from the increased strain on them, allowing the leaflets to wobble as they close or allowing part of a leaflet to flail open in the backflow current caused by the leak it creates.

The chordae are attached to the pappilary muscle, which provides both some cushioning stretch and a secure tether point. Damage to this muscle through infection or infarction (heart attack) can cause the chordae to be loose and the valve to close imperfectly and to bow back (prolapse) into the atrium side under pressure.

The valve leaflets themselves can also thicken from these infections, so they increase strain on the chordae and don't fit together snugly at closing.

As things progress from any of these mitral regurgitation scenarios, the extra pressure on the chordae causes more thickening, stretching, or breakage, which exacerbates the situation over time.

Here are a pair of links to a site that has some good information about mitral regurgitation, and some video with Drs. Carpentier (of the Carpentier-Edwards Permount Magna) and Cosgrove (of the Cleveland Clinic) among others.

http://www.echoincontext.com/learn_anat.asp
http://www.echoincontext.com/2000_video.asp

Best wishes,

 

[Debrinha GT]

Helpful as usual! Thanks BobH!!!!!!!!!!!!!!!!!!

Helpful as usual! Thanks BobH!!!!!!!!!!!!!!!!!!

Thank you very much Bob for your detailed explanation. Although I wasn't really able to understand absolutely everything, I got the gist. Now, you've read a lot about my situation and the results of my echo. Can you tell me where I fit in? How long do you think I might still have left until the next replacement? Any additional comment to what you've already explained will be welcome!! If possible, more especifically about my case. I also wonder if there's any way of knowing how much scar tissue I have and how they remove it once they get in there!?? Thank you again and by the way, I still haven't thanked you for telling MarkRose about me. We've become great firends and are now planning to meet when she comes back from New York. I phoned her the other night and she'll be back in Brazil on the 16th.
Débora