Why do tissue valves last longer in older patients?

[JaneBerm]

Does anyone know why tissue valves last longer in older (65+) patients? Is it because of their physiology or because they are generally less active then younger folks?

 

[Duff Man]

Pretty sure the answer is both, although I don't think they know for certain. There's people that will know alot more about the subject that I hope post for ya soon.

 

[Ross]

Older folks don't calcify valves nearly like younger people.

 

[KristyW]

Does anyone know why tissue valves last longer in older (65+) patients? Is it because of their physiology or because they are generally less active then younger folks?

Duff and Ross are both right...it also has something to do with our immune systems and cell regeneration. Younger people with tissue valves have immune systems that recognize a "foreign" tissue valve. Their bodies produce cells that attach to the tissue valve and calcify. This causes the valves to wear out sooner. For some reason the older we get, the less we produce those calcifying cells, and the tissue valves last longer.

 

[Leah]

I have no sources to cite - but (in advance of my surgery) when I asked more than one highly-regarded surgeon whether remaining very active after AVR with a tissue valve would cause the valve to fail faster, I was told no. It has been expressed to me as "metabolic" or as a function of the immune system. These may be the same thing. I wasn't motivated to delve into the biological details; my primary concern was whether, as a healthy, aerobically active 57-year-old, I would burn through a tissue valve faster than an "older" 57-year-old. I was satisfied that, while no one could predict the time my porcine valve would last, it was a reasonable choice and not more risky because of my state of good health and activity.

 

[Jkm7]

Both my surgeon and cardio have encouraged me to continue my walking and active lifestyle with my bovine valve.

Swimming, golf. brisk walking...... all are fine with them.

 

[marilyn]

For ross

For ross

I have a porcine valve and it is small. Does that have anything to do with the length of time it last? Also, does building blockage in the arteries have any affect on the valve.

 

[Arthur]

Yes, you are right. But the calcium turnover is faster in young adults.
Before 30 years old, the failure rate at 5 years is quite high...

 

[Isfahan]

I asked our surgeon about this in regard to my young (2 year old) son. He said that the rate of calcium dumping is much higher in younger people (extremely high in young children) as this relates to healthy bone growth. I gather the body dumps calcium on structures to build bones? As we age our bones (and rate of calcification of valves) decreases. I have no idea how it works!

 

[tobagotwo]

It's good to try the Search/Advanced Search function on the blue bar near the top of the page. A great deal of writing has been offered on a lot of subjects. It certainly doesn't mean these topics have already been definitively explained, but there's lots of information and opinions on the site's files for whomever is interested. Following is a reprise of a recent post on a closely similar topic:

Some thoughts on calcium...

There has never been a link proven between calcium intake and valve calcification, although it has been studied. It's so unproven that tissue valve companies aren't allowed to discuss reduction of calcium by the patient in relation to the longevity of their valves, or even to discourage the taking of calcium supplements.

The use of calcium supplements doesn't really seem to affect the speed or likelihood of valve calcifications. We all know people who are dairy fiends and who take calcium supplements who have no calcification issues at all throughout their lives. Especially for women, reduction of calcium can lead to bone loss and other issues that overshadow any imagined benefit from the apparenty logical (but also apparently faulty) assumption that it [calcium supplements] might affect valve deposits.

The mineral present on valves is called apatite. It's largely made up of calcium and a mix of other minerals, such as phosphorus and magnesium, and is the same mineral from which bones and teeth are formed. Different concentrations of the trace minerals give it slightly different properties, which turn out to be useful for different bodily purposes. The functions in the body that create the different types of boney materials are probably involved in the creation of valvular apatite deposits, or at least in predisposing the elements of the deposits to coalesce on the valve surface.

Despite numerous attempts to link them, valve "calcification" isn't formed like or associated with the common types of hardened, "calcified" arteries (a form of arteriosclerosis). Nor is it associated with or physically similar to the types of plaques (atheromas) found in atherosclerosis (the most common cause of strokes, and the reason you watch your cholesterol and CRP), although some similar calcification may occur at the base of older plaques over time.

In fact, many valve patients (particularly bicuspid) are found to have otherwise very clean arteries. That doesn't mean that they are mutually exclusive. It just means that one doesn't imply the other, and further diminishes the likelihood of linking them for treatment purposes. Attempts to control valvular deposits with anticholesterol medications (statins) that help to control fatty, atheromic deposits in arteries have been stunning failures, even further separating the two.

The triggers of growth of apatite on a valve seem to be surface chemicals on the valve that are associated with damaged tissue, and to which calcium and other minerals in the blood are attracted. The type of apatite formed is similar to disorganized bone material, and is not unlike the protective boney layer sometimes found coating foreign items trapped inside the body.

The speed of valve apatite growth seems to relate strongly to age, and is comparable to the speed at which normal bone grows and repairs as it relates to the person's age. Once the process has begun, young people tend to calcify their valves (or tissue replacement valves) quite rapidly. As they age and their ability to grow and repair their bones decreases, so does the speed at which their valves or replacement tissue valves will calcify. A bovine valve that may last only five years in a 20-to-30-year-old patient has an average lifespan of over twenty years in those of retirement age.

While age is a generic factor, it's partly because of its effect on the following: people's individual rates of calcium metabolism, the concentrations of bondable minerals in their blood, metabolic inclination (or susceptibility) to transition minerals into bone, and general chemical reactivity (whether it be irritability/inflammation or immune response, which are both sides of the same coin).

The role of the immune system is not understood, but there are some small amounts of immune system markers that tend to appear at the site of apatitic valve calcifications. Whether these are what enable the valve's surface chemicals to attract minerals from the blood or if they are simply there because they are ubiquitous within the body is uncertain.

The upshot is that it most seems to do with the way you metabolize calcium and the general chemical reactivity of your body's immune system. It's how your body is set up to use the calcium, not how much of it is available.

Best wishes,

 

[Cozycat]

Tobagotwo, just happened on your post about calcification of tissue valve in older people. Something was guiding me, because it had so much info I was searching to find. I will have an aortic valve replacement in the next few weeks and have been going back and forth about tissue versus mechanical. Since I am 67 and have done alot of reading on this site, I'm leaning toward a bovine valve and you certainly made parts of the decision process clearer. Will see the surgeon next week and know he will have much to say and discuss, but I now feel more competent about what I need to know. Since I belong to Kaiser I will be going to their cardiac center in LA for the surgery but had my cath done there last week and was happy with the attention and service given me. Anyway, I thank you for your post!

Cozycat - and I think you are what you believe.