Update on Valve Information

[Guest]

Last week in was at a meeting in Chicago where Dr. Robert Emery was one of the speakers. As a young surgeon he was present at the implantation of the first St. Jude valve. (You can read this and think that he is biased toward St. Jude or that he is about the most knowledgeable surgeons on the topic of artificial valves.) The following are nuggets from his talk.

The follow-up on St. Jude valves covers 34,675 patient-years.

98% of all St Jude valves are still working at 25 years. The most common reason for removal is infection. Valve failure is so rare that it should not be a factor in choosing a mechanical valve.

50% of all tissue valves have failed in 12 ? 15 years. The new ones may prove to be better but this will not be known for maybe 10 more years.

He does not recommend a tissue valve for anyone under the age of 60 except for women who wish to have children These women have to understand the increased need for a second surgery. If you get a tissue valve in the aortic position you have a 15 to 30% chance that you will need warfarin because of atrial fibrillation, increased left ventricular size, decreased ejection fraction or some condition that puts you at high risk of clotting.. If it is in the mitral position there is a 25 to 50% chance that you will need warfarin.

Over the long term, (10 years or more) clotting events in patients with mechanical and bioprosthetic valves are equal.

The On-X valve has an unusual shape that makes it difficult to seat properly. The studies that On-X cites about not needing warfarin were mostly among very young people who are less likely to clot.

He is very conservative about bridging. He rarely bridges people with aortic valves. For mitral valves,he stops warfarin 5 days before a procedure and has them hospitalized for 36 hours on a heparin drip before the procedure.

The greatest risk for hemorrhage with warfarin is within the first 3 weeks after the valve is implanted.

Aspirin may be sufficient for an aortic mechanical valve if the person has a normal ejection fraction, normal heart cavity size and is in normal sinus rhythm. .

The strongest predictor of a bad outcome is smoking.

The strongest predictor of a good outcome is that the patient can test their own INR and adjust their own doses at home.

 

[Ross]

Interesting. Seems to go pretty good with what I've been tooting my horn about in here.

 

[kbheart]

"Aspirin may be sufficient for an aortic mechanical valve if the person has a normal ejection fraction, normal heart cavity size and is in normal sinus rhythm."

Really?? Maybe I shouldn't worry about my low INR values since I'm taking aspirin, too?! Is there research supporting this claim?

 

[Ross]

Is there research supporting this claim?

Nope, just his view on the matter!

 

[Guest]

There is no good research because how would you find enough people who met all four criteria?

Anyone reading must not jump to the conclusion that aspirin alone is OK. It might be OK but only if you meet all of the criteria.

 

[Mary]

Dr. Emery sounds like a very knowlegable surgeon.
I hope Ross will make this a sticky thread in valve selection.

 

[kbheart]

There is no good research because how would you find enough people who met all four criteria?

Anyone reading must not jump to the conclusion that aspirin alone is OK. It might be OK but only if you meet all of the criteria.

That's a good point. I'm certainly not ready to stop the coumadin. Maybe Marfan's patients would be good candidates. As far as I know, I would fit the criteria.

 

[Lynlw]

Dr. Emery sounds like a very knowlegable surgeon.
I hope Ross will make this a sticky thread in valve selection.

I've had in interesting pfd on a valve selection Roundtable discussion that Dr. Emery took part it. IT IS outdated since it was from a valve selction symposium in 2001 so alot of the info is old, but I still found it interesting and learned from it there are 3 sections discussng different things that go into selcting the "right' valve for each person the 1st is about
the first of how life expectency plays a role
http://www.onevalveforlife.com/documents/1of3.pdf
the second is about anticoag

http://www.onevalveforlife.com/documents/2of3.pdf

the last is the importance of hemodynamic function
http://www.onevalveforlife.com/documents/3of3.pdf

and again this is 6 year old info, so they numbers have changed, but IMO the over all discusion and hearing each surgeons thoughts were pretty interesting, if they didn't answer all my questions, they at least helped me think of questions to ask.

 

[Karlynn]

Al - thanks so much for the report.

Lyn, thanks for the Round Table discussion. 6 years isn't all that old for medical information. I found their discussion to be very informative and still very relevant in many ways.

 

[OldNick]

Round Table Discussions

Round Table Discussions

Lyn,
Thanks for the links to the Round Table Discussions. Even though it was 6 years ago, much is still applicable. I was pleased to see that my surgeon, Dr. Michael Petracek, was a participant. He has always impressed me as one that is driven to provide the best choices and outcomes for his patients.

I was 63 at the time of my surgery, and he had no problem convincing me to go the St. Jude mechanical valve route, knowing that it required Coumadin and that it also would end my favorite pastime, flying.

 

[tobagotwo]

Please remember when reading this that the information in the lecture regarding tissue valve lifespans and percentage requiring warfarin were not taken from the 34,675 patient-year St. Jude study. We don't know the sources for those statements.

While I'm not indicating at all that Dr. Emory is attempting to mislead, he clearly has a bent. He was, I take it, involved in the study? I note (only from the post) the point made about the clotting risk of mechanical vs. tissue evening out over time, but not about the bleeding risk expanding on the mechanical side over time. As far as "50% of all tissue valves have failed in 12 – 15 years," taking the lifespan of all tissue valves from the beginning of record keeping (although I doubt such a definitive compilation exists) does not produce any valid data. If all brands and types of mechanical valves were lumped together from their inception, the figure would not be 98% at 25 years either.

This isn't intended as a rebuttal to the post, as much as a little leveling of the field.

Best wishes,

 

[Kathleen]

Minneapolis Heart Institute and the cardiac surgeons at Abbott Northwestern Hospital are the group I have been with these last 28 years. Wonderful cardiologists and surgeons. Very interesting articles.
Kathleen

 

[Guest]

As a consultant I'm sure that Dr. Emery had access to St. Jude's records. Remember that he was presenting this to physicians, nurse practitioners etc who were qualified to challenge him on his facts. There were some questions but no challenges to the integrity of the data. He did disclose his conflicts of interest at the start of the presentation.

 

[juliek]

Thank you for posting all this information. I am in the waiting room and this has been extremely helpful!!

 

[twinmaker]

Thanks for sharing this, Al. As a recipient of a St. Jude mechanical mitral valve before it was approved by the FDA (almost 26 years ago), I was told by my surgeon that this valve should last the rest of my life. I had literally turned 29 two days before my surgery. We had our children after my valve repair in 1974, so pregnancy wasn't an issue to have to consider with having to take Coumadin with this new valve. I raised three children, and did everything I wanted to do. I still do what I want. I know there are other things that can cause a valve to fail, but my valve itself is doing great! I'm thankful that my surgeon introduced me to this valve and that I signed all that paperwork to have it implanted before it was approved. LINDA

 

[lance]

Very interesting and informative ...................

Very interesting and informative ...................

This very knowledgeable doctor certainly supports the use of mechanical valves over the shorter life expectancy of tissue valves.

The field would be level if there was a method of determing the number of mechanical valve recipients receiving accurate and timely ACT therapy compared to mechanical valve recipients not receiving accurate and timely ACT therapy.

In other words how many patients on ACT would suffer harm, from whatever source, because of the presence of warfarin in their blood.

 

[starfish11040]

Dr. Emory says:

"The On-X valve has an unusual shape that makes it difficult to seat properly. The studies that On-X cites about not needing warfarin were mostly among very young people who are less likely to clot."

I assume MCRI could produce surgeons experienced with implanting On-x valves who do not have a serious problem seating the valve. And I would be very curious about how MCRI would respond to Emery's claim about it's clotting studies.

"Aspirin may be sufficient for an aortic mechanical valve if the person has a normal ejection fraction, normal heart cavity size and is in normal sinus rhythm."

Has anyone heard of this? I don't know of anyone with a mech valve who has been told that aspirin is sufficient.

 

[ALCapshaw2]

Bob H (Tobagotwo) wrote:

"While I'm not indicating at all that Dr. Emory is attempting to mislead, he clearly has a bent. He was, I take it, involved in the study? I note (only from the post) the point made about the clotting risk of mechanical vs. tissue evening out over time, but not about the bleeding risk expanding on the mechanical side over time."

Bob - In your last statement above, are you suggesting that the Coumadin Risk is CUMULATIVE?

Does this mean that you did not see (or agree) with the post from one of our members (sorry, Pumphead effect, I forgot his name) which pointed out that a Cumulative Risk would mean that at some point in time, the risk would EXCEED 100% per year which we know is NOT possible (and does NOT occur).

He went on to calculate the True Risk vs time using a basic statistical model 'assuming' constant risk per year. Note that he Teaches Statistics at Notre Dame University (if I remember correctly).

'AL Capshaw'

 

[tobagotwo]

No, Al. It's not cumulative at all, to my knowledge. The nature of risk is like flipping a coin. While we know that somehow, over time, the chance of heads is 50%, the chances of heads or tails begin brand new again for each flip of the coin, no matter how many times tails has come up in a row. Or in this case, they begin anew for each new day/year/whatever timespan of your choice. They don't add up to become a certainty.

What I meant is that the nature of the risk evolves over time. As you age, the risk of stroke levels off, and slowly reduces, as those who are going to have that problem usually seem to develop it earlier in the game. At the same time, your blood vessels are becoming more fragile with age, and the risk of intracranial and gastric bleeding slowly increases, for which warfarin use presents a somewhat greater liability.

It's not that your overall risk increases, but that you effectively trade the type of risk over time (meaning, "as you progress beyond retirement age").

Best wishes,

 

[ALCapshaw2]

Thanks for clarifying your statement Bob.
I understand and agree. I expect others
will benefit from the added detail as well.

'AL Capshaw'