Long-term outcomes of valve replacement with modern prostheses in young adults.

[Dustin]

2005 Mar;27(3):425-33; discussion 433. Epub 2004 Dec 30.

Long-term outcomes of valve replacement with modern prostheses in young adults.

Ruel M, Kulik A, Lam BK, Rubens FD, Hendry PJ, Masters RG, Bedard P, Mesana TG.

Division of Cardiac Surgery, University of Ottawa Heart Institute, 40 Ruskin Street, Suite 3403, Ottawa, Ontario, Canada K1Y 4W7. [email protected]

OBJECTIVES: To examine the multiple impacts of valve replacement on the lives of young adults. METHODS: Patients (N=500) between age 18 and 50 who had aortic valve replacement (AVR) and/or mitral valve replacement (MVR) with contemporary prostheses were followed annually. Events, functional status, and quality of life were examined with regression models. RESULTS: Median follow-up was 7.1+/-5.3 years (maximum 26.7 years). Five, 10, and 15-year survival was 92.7+/-1.7, 88.3+/-2.4 and 80.1+/-4.7% after AVR, and 93.1+/-2.3, 79.5+/-4.3 and 71.5+/-5.4% after MVR, respectively. Survival decreased with concomitant coronary disease (hazard ratio (HR): 4.5) and preoperative LV grade (HR: 2.0/grade increase) in AVR patients, and with atrial fibrillation (HR: 5.5), coronary disease (HR: 5.7), preoperative left atrial diameter (HR: 3.0/cm increase) and NYHA class (HR: 2.1/class increase) in MVR patients. Despite reoperation, late survival was equivalent between bioprostheses and mechanical valves in both implant positions. The ten-year cumulative incidence of embolic stroke was 6.3+/-2.4% for mechanical AVR patients, 6.4+/-2.9% for bioprosthetic AVR patients, 12.7+/-3.9% for mechanical MVR patients, and 3.1+/-3.1% for bioprosthetic MVR patients. Atrial fibrillation (HR: 2.8) and smoking (HR: 4.0) were risk factors for stroke in MVR patients. In AVR patients, SF-12 physical scores, freedom from recurrent heart failure, and freedom from disability were significantly higher in bioprosthetic than mechanical valve patients. Career or income limitations were more often subjectively linked to a mechanical prosthesis in both implant positions. CONCLUSIONS: Late outcomes of modern prosthetic valves in young adults remain suboptimal. Bioprostheses deserve consideration in the aortic position, as mechanical valves are associated with lower physical capacity, a higher prevalence of disability, and poorer disease perception. Early surgical referral and atrial fibrillation surgery may improve survival after MVR.

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As has been argued by many, this paper reinforces the idea that long-term survival rates are the same for both valve types. What is striking, however, is that the risk of embolic stroke in the aortic position is the same for both valve types in this study.

 

[Andyrdj]

Very Interesting

Very Interesting

I'd heard the survival stats before, but wasn't aware of the stroke risk similarity.

It would be interesting to compare this risk with that of the general population. It mentioned A/Fib in MVR (I know of the higher risk in mitral position) and smoking as risk factors for strokes. But is this not also true of the Aortic position? I'd be surprised if it made no difference, I seem to remember that smoking is generally a stroke risk for the population overall.

Perhaps a contributor to the bioprosthetic stroke risk is bits falling off the valves? I know in porcine valves tears do occur, and this is supposedly one of the strengths of bovine pericardial valves - less tearing.

Or is it large calcium deposits falling off into the blood?

I wonder if I have a bioprosthetic aortic valve and no warfarin I can temper my stroke risk with e.g. aspirin, or herbal stuff (gingko biloba?).

 

[Dustin]

It would be interesting to compare this risk with that of the general population. It mentioned A/Fib in MVR (I know of the higher risk in mitral position) and smoking as risk factors for strokes. But is this not also true of the Aortic position? I'd be surprised if it made no difference, I seem to remember that smoking is generally a stroke risk for the population overall.

I've read that smoking (nicotine) tends to narrow the blood vessels in the brain, thereby increasing the risk of blood clots and thus stroke.

Perhaps a contributor to the bioprosthetic stroke risk is bits falling off the valves? I know in porcine valves tears do occur, and this is supposedly one of the strengths of bovine pericardial valves - less tearing.

Or is it large calcium deposits falling off into the blood?

I have no idea, though it sounds plausible that the aortic position could be more "violent" than the mitral position, causing vegetation to break free from the tissue leaflets. Having said that, new tissue treatment techniques sported by the Magna for example could reduce vegetation growth, so the above results may turn out to be conservative.

 

[Andyrdj]

Statins seem to help

Statins seem to help

see this article...
http://news.bbc.co.uk/2/hi/health/3533625.stm

 

[MarkU]

Events, functional status, and quality of life were examined with regression models.

<edit>

In AVR patients, SF-12 physical scores, freedom from recurrent heart failure, and freedom from disability were significantly higher in bioprosthetic than mechanical valve patients. Career or income limitations were more often subjectively linked to a mechanical prosthesis in both implant positions.

CONCLUSIONS: Late outcomes of modern prosthetic valves in young adults remain suboptimal. Bioprostheses deserve consideration in the aortic position, as mechanical valves are associated with lower physical capacity, a higher prevalence of disability, and poorer disease perception. --

I'd like to see the data that backs up these conclusions. I find it hard to believe that I'm so far out on the edge of the bell curve statistically. I have vastly improved cardiac function with my mechanical valve, to the point where my left ventricular hypertrophy reversed itself within 12 months of my AVR. I exercise very strenuously and my resting heart rate has dropped from the mid 60's to low 40's. I have no other indicators of cardiovascular disease- to quote my cardiologist, I have "monster arteries", large and unclogged.

My quality of life is just fine, thank you. If anything I am guilty of trying to cram too much stuff into my life. Oh, and I changed jobs after my surgery to a higher-paying and more satisfying career.

So, am I just extremely lucky or are these conclusions about mech valvers BS?

 

[Andyrdj]

well...

well...

Two statements

"In AVR patients, SF-12 physical scores, freedom from recurrent heart failure, and freedom from disability were significantly higher in bioprosthetic than mechanical valve patients"
and
"Bioprostheses deserve consideration in the aortic position, as mechanical valves are associated with lower physical capacity, a higher prevalence of disability, and poorer disease perception"

Notice that every negative here is comparitive

This could easily mean, for example, disability in 10% of mech patients compared to 6% of bio patients. Or 35% and 30%, or other such numbers.

Nowhere does it say "problems with majority of mech patients" - just "higher risk". Your own experience is not at all inconsistent with this study.

There is no damning assault on the mech valve being stated here - merely a cautious leaning towards bio valves.


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[tobagotwo]

There is a somewhat outrageous and unsupported (at least in this article) claim that "mechanical valves are associated with lower physical capacity, a higher prevalence of disability, and poorer disease perception." If that were generally so, it might well be due to doctors themselves, much more than the valves. We've all seen the intense caution and limitations that most cardiologists attempt to impose on their warfarin patients. That can easily lead to a less physical lifestyle and a less robust patient. Professional education might affect that result very positively.

Mark didn't listen to those insurance-pleasing limitations. And it didn't happen to him. Many others on this site as well. The aortic pressures from current mechanical valves are at least as low as those from tissue valves, and usually lower. So, where's the physical reason for that lower physical rating? There really doesn't seem to be one. So would the valve be the culprit, or would it more likely be the physicians' overcautious attitude?

Stroke statistics from carbon (mechanical) users should also be taken with a grain of salt. My personal belief is that the stroke relationship to carbon valves correlates very highly with the efficacy of the coumadin therapy. I believe there are a lot of poorly-trained professionals currently involved in warfarin therapy, and particularly a great deal of professional ignorance about bridging therapy for procedures. I believe that as home testing increases, the stroke rate will decrease. The rest will have to be a result of education, and of patients learning to question their doctor's decisions about going off of Coumadin unnecessarily for procedures.

The real danger isn't Coumadin: it's the ignorance surrounding it.

The point of the above is not that the numbers are wrong, but that you can improve your personal "number" by avoiding the more obvious pitfalls. Statistics aren't inescapable unless you take no action to overcome them where the opportunity presents itself.

The true fascination in these statistical voyages can be in trying to determine the causations for the numbers. The study's about valves, right? Or is it? What's really being measured? What other, surrounding factors, besides whether a valve has a natural or industrial parentage, were really involved in creating the conditions that caused those percentages? When we look at the numbers that stick out, how can we change our viewpoint to see what the likely factors could be, and whether they're controllable?

As far as the study itself, the stroke numbers for tissue valvers are on the high side. Were the ages comparative? Many studies don't work to match ages between groups of carbon and tissue users. Taken at random, the average age of the tissue user population is quite a bit older than that of the carbon users. Carbon is traditionally used in younger people, and is far more frequent in them. Tissue is traditionally used in retirees. As such, a comparison of stroke percentage may more reflect the comparative ages of the two groups than anything else. In all studies that I have seen, age has the number one correlation with stroke potential. That frequently is a cause of skewed stroke statistics.

While I may have a specific beef with the elevated stroke numbers for tissue users, and a possible cheap shot taken at carbon valves, I agree in general that the long-term survival rates are quite similar. It's not surprising, and it does dovetail with other studies from the past.

In my opinion, these results should not deter someone from choosing either valve type.

Best wishes,

 

[OldManEmu]

Physical capacity

Physical capacity

Even though I don't have a mechanical valve from my own research I am inclined to agree with MarkU. A modern mechanical valve has such good fluid dynamics that unless you are an elite level athlete it will not impair your physical performance. As for left ventricular remodelling there is little to differentiate between modern mechanical and tissue valves. Other issues should determine your choice other than these.