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PJmomrunner
Well-known member
It seems like we've been hearing about a new catheter-placed heart valve at the rate of 1+ per week for the last couple of weeks. At this rate there could be a vastly different "standard" set of choices in the not-too-distant future.
P
Phyllis
What wonderful news for our "wee" ones- only hope that it becomes the standard of care SOON!
A
Andyrdj
Getting rid of older valves
Getting rid of older valves
Can anyone add some extra info as to how feasible it might be to remove a natural valve or one planted the old way via catheter before putting one of these in?
Getting rid of older valves
Can anyone add some extra info as to how feasible it might be to remove a natural valve or one planted the old way via catheter before putting one of these in?
aussigal
Well-known member
Andyrdj said:
good point !...
surely one of our members knows the answer
As I understand it, when using this method, the old one isn't removed. It's actually mashed into the side walls, often with valvuloplasty balloons, and then the new one is expanded in its place.
Most of the catheter-placed valves are tissue valves. This one appears to be a bileaflet mechanical. Both types are placed by a modified stent that, when expanded, inserts hooks into the side walls where the sutures would normally be placed. The expanded stent also helps keep the mashed remnants of the prior valve in place.
That part does leave open the question of scar tissue long-term, or the possiblilty of rough edges or a ledge at the edge of the stent, if placement is imperfect. Ledges can allow clots by creating eddies in the bloodflow, and can be attractive promontories for apatitic (calcium) buildups. This type of valve hasn't been out long enough to have any kind of a handle on these possibilities, so these thoughts are mere speculation.
The most likely reasons that the old valve is not removed are the amount of extra time it would take (while you effectively have no valve), and the concern for detritus escaping into the bloodstream. Because of this, a carbon valve isn't currently replaceable by this method. An original valve or most tissue replacement valves could be replaced this way, including a Ross-placed valve or a homograft.
It would seem that this valve would make more sense in older children whose aortic roots have fully grown (I remember that being about age 14, but may be mistaken). Otherwise, it would need replacement as the child grows. Unless the valve can be reasonably folded back into its stent and withdrawn without doing more damage to the outer walls or releasing debris into the bloodstream, you're back to OHS to replace it later. The valve root could be expanded to accommodate an adult-sized valve, but that requires OHS, and then you'd use a superior, regular carbon (mechanical) valve, because you'd already have compromised the reason for catheter placement.
Each new catheter-placed valve touts itself as being breakthrough technology, as if the method had never been used before, although it's been around for several years. The valves themselves are still emerging technology though, and if perfected, may enahnce many of our lives a dozen or more years from now. It's to be remembered that all of the catheter-placed valves at this time are compromises between placement capability and functionality as valves. Certainly, even now they can be a blessing to those who cannot withstand OHS, and for that alone the news of each new approach to it is worth exploring.
Best wishes,
Most of the catheter-placed valves are tissue valves. This one appears to be a bileaflet mechanical. Both types are placed by a modified stent that, when expanded, inserts hooks into the side walls where the sutures would normally be placed. The expanded stent also helps keep the mashed remnants of the prior valve in place.
That part does leave open the question of scar tissue long-term, or the possiblilty of rough edges or a ledge at the edge of the stent, if placement is imperfect. Ledges can allow clots by creating eddies in the bloodflow, and can be attractive promontories for apatitic (calcium) buildups. This type of valve hasn't been out long enough to have any kind of a handle on these possibilities, so these thoughts are mere speculation.
The most likely reasons that the old valve is not removed are the amount of extra time it would take (while you effectively have no valve), and the concern for detritus escaping into the bloodstream. Because of this, a carbon valve isn't currently replaceable by this method. An original valve or most tissue replacement valves could be replaced this way, including a Ross-placed valve or a homograft.
It would seem that this valve would make more sense in older children whose aortic roots have fully grown (I remember that being about age 14, but may be mistaken). Otherwise, it would need replacement as the child grows. Unless the valve can be reasonably folded back into its stent and withdrawn without doing more damage to the outer walls or releasing debris into the bloodstream, you're back to OHS to replace it later. The valve root could be expanded to accommodate an adult-sized valve, but that requires OHS, and then you'd use a superior, regular carbon (mechanical) valve, because you'd already have compromised the reason for catheter placement.
Each new catheter-placed valve touts itself as being breakthrough technology, as if the method had never been used before, although it's been around for several years. The valves themselves are still emerging technology though, and if perfected, may enahnce many of our lives a dozen or more years from now. It's to be remembered that all of the catheter-placed valves at this time are compromises between placement capability and functionality as valves. Certainly, even now they can be a blessing to those who cannot withstand OHS, and for that alone the news of each new approach to it is worth exploring.
Best wishes,
Can this cathetered valve be easily removed for replacement, or is it a one way ticket? I guess that tissue overgrowth, calcification, or what have you may render the valve impossible to remove by means of catherisation. OHS is likely to be required when you need replacement. No?
A
Andyrdj
About what I expected
About what I expected
tobagotwo has confirmed what I know, and sadly the current major obstacle with this is likely to be detritus going into the bloodstream, causing strokes etc.
Plus, I wonder what will happen if anything goes wrong? Emergency chest opening kit to the fore?
About what I expected
tobagotwo has confirmed what I know, and sadly the current major obstacle with this is likely to be detritus going into the bloodstream, causing strokes etc.
Plus, I wonder what will happen if anything goes wrong? Emergency chest opening kit to the fore?
Imho
Imho
Getting the valve in place by means of a catheter and having it work is still in the research phase, but doable. Soon the problem becomes how practicable is this for the majority of valve pts. Would a person who is a candidate for a repair choose a catheter valve or go for a tradition OHS? Obviously, a pt. with a mech. valve could not utilize a catheter placed valve, but since the newest mech. valve don’t wear out there would be no reason for its use in a mech. valve pt. In the rare case where a mech. valve would need replacing, it would have to be done the traditional way. The bigger obstacle to overcome, is how to redo a catheter implanted valve, with another catheter implanted valve. Since there is no long term data on how these compressed valves last, this will be of major importance in determining the effectiveness of this solution. This is of particular concern When working with a small child’s heart, because of the small diameter of the valve opening. Once that small diameter catheter valve is placed, it will not grow as normal valve would. As the rest of the heart grows normally, by definition a catheter implanted valve would become stenotic.
As far as the “Rotorooter” method of explanting an existing valve much like a TURP procedure, that is a long way off because of the problem already pinpointed. However,
several stent manufactures are working on filters that open up like umbrellas, with the point of the umbrella pointing downstream in the blood flow. They have met with mixed results. The most difficult being how do you work in a small space, while at the same time “fishing” around all the catheter lines necessary to get a specific job done.
Let us not forget that although catheter procedures are safer then OHS, they still carry a risk of death, as we all know when we had to sign the consent form!
As to Andyrdj question about what to they do if a particle gets in to the bloodstream (every doctors worst dream) – they just wait to see where it end up and how much damage it does. It can do nothing, but it can cause death.
I would caution everybody concerning the next “Greatest discovery” not to bank anything
till it is proven in clinical trials. I, as well as members like Al Lodwick, Marty, Joanne, Nancy and Joe
Geebee and others who have been “around the block”, can’t even begin to count on both
hands the number of PR releases we have read that promised to next great fix and then was never heard from again. PR releases are designed to get people and institutions money, plain and simple. Real scientists get the word out by releasing their data in professional journals, not PR Releases- so be very skeptical of them!
[What ever did happen to COLD FUSION anyway?]
I have been hearing that tissue engineered valves were just ten years away since my 3rd valve surgery in 1982- glad I didn’t hold my breath waiting on that on one!
Imho
Getting the valve in place by means of a catheter and having it work is still in the research phase, but doable. Soon the problem becomes how practicable is this for the majority of valve pts. Would a person who is a candidate for a repair choose a catheter valve or go for a tradition OHS? Obviously, a pt. with a mech. valve could not utilize a catheter placed valve, but since the newest mech. valve don’t wear out there would be no reason for its use in a mech. valve pt. In the rare case where a mech. valve would need replacing, it would have to be done the traditional way. The bigger obstacle to overcome, is how to redo a catheter implanted valve, with another catheter implanted valve. Since there is no long term data on how these compressed valves last, this will be of major importance in determining the effectiveness of this solution. This is of particular concern When working with a small child’s heart, because of the small diameter of the valve opening. Once that small diameter catheter valve is placed, it will not grow as normal valve would. As the rest of the heart grows normally, by definition a catheter implanted valve would become stenotic.
As far as the “Rotorooter” method of explanting an existing valve much like a TURP procedure, that is a long way off because of the problem already pinpointed. However,
several stent manufactures are working on filters that open up like umbrellas, with the point of the umbrella pointing downstream in the blood flow. They have met with mixed results. The most difficult being how do you work in a small space, while at the same time “fishing” around all the catheter lines necessary to get a specific job done.
Let us not forget that although catheter procedures are safer then OHS, they still carry a risk of death, as we all know when we had to sign the consent form!
As to Andyrdj question about what to they do if a particle gets in to the bloodstream (every doctors worst dream) – they just wait to see where it end up and how much damage it does. It can do nothing, but it can cause death.
I would caution everybody concerning the next “Greatest discovery” not to bank anything
till it is proven in clinical trials. I, as well as members like Al Lodwick, Marty, Joanne, Nancy and Joe
Geebee and others who have been “around the block”, can’t even begin to count on both
hands the number of PR releases we have read that promised to next great fix and then was never heard from again. PR releases are designed to get people and institutions money, plain and simple. Real scientists get the word out by releasing their data in professional journals, not PR Releases- so be very skeptical of them!
[What ever did happen to COLD FUSION anyway?]
I have been hearing that tissue engineered valves were just ten years away since my 3rd valve surgery in 1982- glad I didn’t hold my breath waiting on that on one!
Nancy
Well-known member
Regarding jumping right into surgery with any new technology, let us never forget Synergraft valves, Silzone valves and some of the Bjork-Shiley valves. We have some members here who have had experiences with some of the above, and some sad experiences.
Theory is one thing, but actually getting things to work in living human beings is quite another.
Theory is one thing, but actually getting things to work in living human beings is quite another.
A
Andyrdj
A bit of related (good) news
A bit of related (good) news
I cna't find the link, but there has been a bit of news recently regarding tissue engineering.
Engineered valves up to now have typically involved growing the patient's own cells onto a scaffold, implanting it, and relying on diffusion of oxygen from surrounding cells (or perhaps the actual bloodstream?) to give the valve the oxygen it needs to survive.
This is ok for smaller structures, but a large complex organ like the heart needs blood vessels and capillaries throughout its tissues. To grow a complete new heart, researchers need to be able to grow these blood networks within the tissue.
I read somewhere that someone had discovered how to do this, and immediately my thoughts were that this might improve our ability to grow new tissue valves permeated with capillaries, and perhaps sections of aortic root for replacement?
Is there anyone who can add further info? Would love to find which research groups/hospitals are in trial stage for their tissue engineered valves.
A bit of related (good) news
I cna't find the link, but there has been a bit of news recently regarding tissue engineering.
Engineered valves up to now have typically involved growing the patient's own cells onto a scaffold, implanting it, and relying on diffusion of oxygen from surrounding cells (or perhaps the actual bloodstream?) to give the valve the oxygen it needs to survive.
This is ok for smaller structures, but a large complex organ like the heart needs blood vessels and capillaries throughout its tissues. To grow a complete new heart, researchers need to be able to grow these blood networks within the tissue.
I read somewhere that someone had discovered how to do this, and immediately my thoughts were that this might improve our ability to grow new tissue valves permeated with capillaries, and perhaps sections of aortic root for replacement?
Is there anyone who can add further info? Would love to find which research groups/hospitals are in trial stage for their tissue engineered valves.
Nancy
Well-known member
Wouldn't they have to keep blood moving through those capillaries to keep them viable? How would that be done while the heart was growing--some kind of little pump?? And how about maintaining the blood supply?
Would the heart be grown outside the body until it gets big enough? Or does it incubate in the person's body somewhere until it gets big enough?
What a complicated study!
Would the heart be grown outside the body until it gets big enough? Or does it incubate in the person's body somewhere until it gets big enough?
What a complicated study!
A
Andyrdj
Hmmm
Hmmm
Interesting point. Perhaps they immerse the growing tissue in super oxygenated blood?
One thing's for sure, though - the same problems were overcome by each and every one of us in the womb!
Hmmm
Interesting point. Perhaps they immerse the growing tissue in super oxygenated blood?
One thing's for sure, though - the same problems were overcome by each and every one of us in the womb!
