Question about homographs

[jamie14512]

Hi,

Why do tissue valves tend to be used over homographs?

Kind regards,

Jamie

 

[Survived03]

One reason could be availability of homographs. Second reason could be limitations on the available size and fit to the individual. Bio’s and mechanical valves are like picking the right size shoe from a shelf of valves available (statement by my last surgeon).

 

[jamie14512]

Thank you, if a biological tissue valve and a homograph valve were both available and fit the individual. Which would last longer?

 

[tommyboy14]

Hi Jamie,

I think the answer is Homograft. At least that is what past studies used to suggest. According to those studies you could get 15-20 years. I think @pellicle has a really good reference on the durability.

However, when I asked about this option when I had my own first surgery in the UK in 2014, the surgeon said that these studies would not be applicable anymore for the following reason: Up until the 1990s, early 2000s, Homografts would be harvested from donor hearts. But then heart transplantation really took off. Complete donor hearts are like gold dust. So you would potentially end up getting a lower quality homograft then used in past studies, which is why it is unclear if those studies would still be applicable to your outcome.

But there is a new type of homograft available in the UK, a decellularized homograft. The lead hospital is in this trial is in Germany, but the Royal Brompton in the UK is participating as well. The idea is that by removing foreign cells, your own body will treat this homograft as its own and then repair it as well, making this more of a long-term solution. However, this is pretty experimental. They just published 5-year data and 6% of patients already had moderate aortic regurgitation.

http://www.arise-clinicaltrial.eu/home.html#3

Also, a different type of decellularization of homograft has been tried by the Mayo Clinic in the US in the early 2000s:
https://www.jtcvs.org/article/S0022-5223(16)30024-1/fulltext

in that study, freedom from reoperation was only 51% after 10 years. that is worse than many bio valves, even in young people.

So I would say, yes it is great that we have this new decellularized homograft approach, but there is absolutely no way of knowing if this is better or worse. This is a bit like playing the lottery. Not something one should do with one's health

 

[jamie14512]

Hi Tommy,

Thank you so much, this is really helpful, you have provided some fantastic information and links. Ill readup on these

I'm hesitant about getting a experimental valve as it may be ineffective.

 

[pellicle]

Hi
firstly its not "new and experimental" by any means, it has a long history.

Why do tissue valves tend to be used over homographs?

firstly its homograft (long ago it was called an allograft) because like a skin graft (which is usually an autograft meaning from yourself) or grafting a branch onto a tree, it is the transferring of living (called viable) tissue from one individual to another. This is entirely different from transferring a bit of dead chemically processed "leather" wrapped around a steel framework or a bit of ceramic as a prosthesis.

I had a homograft in 1992 which by then was a well established path way. The institution which did my surgery was perhaps the world leader in that speciality.

https://pubmed.ncbi.nlm.nih.gov/11380096/

Dr Obrien and Dr Stafford were my surgeons for my first OHS (a "repair" at age 10) and second OHS (homograft at age 28)

The homograft was not the cause for reoperation in 2011 it was the aneurysm. Due to this being then my third OHS I took about 5 seconds to decide that a mechanical with a pre-attached graft would be the best choice for me at #3

Thank you, if a biological tissue valve and a homograph valve were both available and fit the individual.

lots of reasons so lets just summarise them quickly:

• source of material - people need to die and donate their aortic valve ... donors need to pass a variety of tests (disease like viral infections, appropriate lifestyle of no smoking ...) and then the valves need to be excised from the donor (the person who died) in a timely fashion (a good read of a critical point here)
• tissue typing
• cryo-storage and its associated costs (if you have a finance background transfer the knowledge surrounding "cost of carry")
• supply needs to also include correct sizes
• last but not least something else may drive the reoperation need even if the donor valve did last indefinitely (which for various reasons we are still trying to understand doesn't)

to answer this question:

Which would last longer?

You'll find in the above study something like:

For all cryopreserved valves, at 15 years, the freedom was​

⦁ 47% (0-20-year-old patients at operation),​

⦁ 85% (21-40 years), <-- you are in this cohort​

⦁ 81% (41-60 years) and​

⦁ 94% (>60 years).​

However the above is "best case" scenario from an institution which is a world level center of excellence (or was, as they've sort of gone out of it now).

Statistically there is next to no way you'd get 15 years from a tissue valve at 28 ... let alone 20. However because I prefer to advise people to minimise their exposure to repeat surgery (because you always want to have something up your sleeve) I would strongly suggest mechanical for you.

Happy to discuss this in greater detail if you wish (so PM me if you wish) but I also covered some of the points in this post:

https://www.valvereplacement.org/th...ace-my-mid-ascending-aorta.889477/post-931239

Best Wishes

 

[pellicle]

Oh, and @jamie14512

https://www.valvereplacement.org/threads/28-yrs-old-with-bav-severe-ar.889431/post-930389

and well worth a listen if you are "avoiding blood thinners"

https://www.medscape.com/viewarticle/838221

 

[pellicle]

... I think @pellicle has a really good reference on the durability.

Thanks for the @ mention

 

[jamie14512]

I'm probably going to go with mechanical but just considering:
A xenograft tissue valve seems pointless as it may only last me 5 years
If i somehow could get a homograph, given that i want to get into boxing at a semi-athlete level, would it be unlikely for a homograph to last 10 years?

 

[pellicle]

Hi

If i somehow could get a homograph, given that i want to get into boxing at a semi-athlete level,

I don't think the exersize would have anything to do with the longevity stats of a homograft, but 'semi-athlete' level of boxing is perhaps doable with even a mechanical. I would simply pay attention to head strikes (which you should anyway) and learn enough about managing your INR to be nearer 2.0 for sparring times. Such can be done simply by "learning about yourself" and either Chuck or I could help you there.

I was told quite clearly and with a deliberate pause by my surgeons to avoid professional level competitive sports; at least twice. But still I was not a shut in by any means.

I think that you need to see that some of the ambiguity of "who you are" has been revealed early and that you have the "engine management light" lit on your dash saying "you may not be athlete material" if living long is your goal.

Being super fit is not what you might think it is
https://www.aafp.org/pubs/afp/issues/2019/0115/p78.html

Most clinicians are aware of the well-established association between physical fitness and cardiac health. How many are aware, however, that high levels of physical fitness predispose patients to cardiac rhythm abnormalities? We were not until each of us experienced one of the two most common serious fitness-related cardiac arrhythmias: atrial fibrillation/flutter (Dr. Weiss) and sinus bradycardia with ventricular tachycardia requiring pacemaker insertion (Dr. Walling). ​

It actually makes you a bit more vulerable to heart issues than just regular levels of fitness. You already know you are now a bit more vulnerable to heart issues.

The following is a good primer on homograft 'harvesting' and why fewer and fewer are doing it can be inferred from that if you read it carefully
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC7853167/

would it be unlikely for a homograph to last 10 years?

its very much down to the individual and to the centers long term outcomes, read those stats again carefully; specifically the exact words "For all cryopreserved valves, at 15 years, the freedom [from reoperation] was 85% 21-40 year-old patients at operation)"

so 15% needed re-operation. We don't know why or their individual lifestyle parameters.

Don't forget that each successive OHS (even TAVI as I'm understanding it) makes you more vulnerable to the above issues (and more).

Something to read:
https://www.newsweek.com/my-turn-climbing-everest-bionic-heart-99749

HTH

 

[Dano64]

Jamie,

I had my first valve replacement surgery in 2001 with a homograft and I was very happy with my choice. Like Pellicle, I needed a 2nd surgery 21 years later due to an aneurysm. The homograft still had some life left but was replaced to avoid another OHS sooner rather than later. It was not mentioned as an option again for me in 2022. I wish it was an option as I did very well with it. Good luck to you on your decision and well-being going forward!