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Eur J Cardiothorac Surg 2004;26:S59-S61
© 2004 Elsevier Science NL
Review |
Department of Thoracic and Cardiovascular Surgery, Hannover Medical School, Carl-Neuberg-Str. 1, 30625 Hannover, Germany
* Tel.: +49 511 5326580; fax: +49 511 5325404. (Email: haverich{at}thg.mh-hannover.de).
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Abstract |
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 Top Abstract 1. Current practice2. Drivers for change3. Options for progress4. Key issuesAppendixReferences |
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Key Words: Tissue engineering • Heart valves • Myocardial replacement • Autologous repair
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1. Current practice |
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TopAbstract1. Current practice2. Drivers for change3. Options for progress4. Key issuesAppendixReferences |
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Harvesting autologous grafts is associated with a defined act of destruction and site specific complications as well as extension of operating time. Current valve implants do either require life-long anticoagulation or they are prone to premature degeneration with the need of re-replacement. Myocardial replacement, using functional tissue, has not yet reached clinical reality.
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2. Drivers for change |
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TopAbstract1. Current practice2. Drivers for change3. Options for progress4. Key issuesAppendixReferences |
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In coronary surgery, arterial, autologous grafts not harvested in toto from the patient at the time of surgery would allow for shorter operating times and the promotion of minimal invasive, percutaneous techniques.
Myocardial replacement has not become clinical reality. There is a definite need both in pediatric cardiac surgery and in adults, where replacement strategies rather than resectional therapies alone for the treatment of long-term sequelae of myocardial infarction would be highly desirable.
It is important to note that the medical device industry at present is definitely not a driver for change; the opposite appears to be true.
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3. Options for progress |
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TopAbstract1. Current practice2. Drivers for change3. Options for progress4. Key issuesAppendixReferences |
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4. Key issues |
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TopAbstract1. Current practice2. Drivers for change3. Options for progress4. Key issuesAppendixReferences |
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Appendix |
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TopAbstract1. Current practice2. Drivers for change3. Options for progress4. Key issuesAppendixReferences |
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Dr A. Kappetein (Rotterdam, Netherlands): I fully agree with you that we should restructure research. Do you have a vision how the Association could help with restructuring research?
Dr Haverich : I think the first thing is a working group that deals with biologic implants.We should exchange some ideas and visit each other and see how those people are doing, maybe with a segmental approach to the research. This is what we have actually done with Walter Weder, we look at the matrix and he looks at the chondrocytes, and then at the end we would like to put those things together for tracheal replacement. But I think we must get into it in an organized fashion, and it would not be the first society that would have a working group in this specific field, and in that working group we should include basic science, cell biology, physiology, and other disciplines. Otherwise I don't think we can get towards a more structured approach.
Dr G. Gerosa (Padova, Italy): The whole business about tissue engineering started in 1971 by Alain Carpentier, and then the group in Boston, for about 20 years have produced papers on tissue engineered valves. So how do you explain the fact that we didn't move to the clinical application so far?
Dr Haverich : Our group has done two implants now, they are two years out in children, and those two valves in the pulmonary position are doing fine. If you show those echoes to a cardiologist who doesn't know what has happened, if he looks at the leaflet he thinks it is the patient's own valve. We have been very careful. We wanted to have two-year results in those two early clinical experiences before we go on from there. The Munich group has used homografts and reseeded them with endothelial cells autologously, plus the Berlin group with 143 implants now. So I think we are in the process of getting into a very early clinical implant series.
I think the reason why those groups who started very early with these tissue engineering approaches in heart valves were not successful in terms of transferring it into the clinical arena was the fact that they were using nonbiologic matrices, and that poses a lot of problems. The degradation process of those polymers very often causes inflammation; the hydrolysis process very often ends up with a very soft remaining matrix leading to destruction. So I personally believe that the biologic matrix has a lot of advantages.
Dr Gerosa : The two valves that you mentioned that you implanted in the pulmonary position were tissue engineered valves or tissue regenerated? I mean, they were decellularized and then implanted?
Dr Haverich : Those were homografts, not xenogenic but allogenic, decellularized in a routine fashion, and repopulated with hematopoietic stem cells in vitro.
Dr J. Vaage (Oslo, Norway): I just want to congratulate you on this very interesting talk and also your great work in this field, and this is probably really into the future, and this has been what we have heard early in this session as well. I think that maybe the most constructive suggestion that has come today is your suggestion of making like a working group for this, and maybe the Society should sit down, let's say, as a basic science committee to identify which fields are important for us, because it is more than tissue engineering, it is cell transplantation and various aspects, and maybe this group should set down a strategy to develop this within our specialty, how to get funding and how to actually work for the future.
Dr Haverich : Thank you for that comment. I looked through the program of this two-day meeting and made a few remarks where I would see working groups that should start promoting various aspects: number one, getting concentrated on one specific issue, number two, getting funding for the research, number three, getting the research more organized in a fashion that not everybody is doing the same but what I titled segmented research. Number four, preparing reimbursement for those things, because this is the only way that medical industry or the device industry will hop on to those concepts, and this is very difficult.
Your suggestion does not only apply to cell biology and cell implants and tissue engineering but also for some of the other fields that we have been discussing today in terms of getting organized within the Society. Cardiology is doing that, both on a national and on a European level, in a very, very powerful way.
Dr Vaage : Can I make a comment to that? I think that if you are looking to the future and talking about the biological part and the device part, these are usually often quite separated in the minds of people. So devices and biology may not always fit together.
Dr Haverich : That is true, and this is why I said that logistics is a point of maximum discussion, because the classical device industry says, well, this is no concept. But I promise 10 years from now, 50% of all patients will receive tissue engineered heart valves and the current device industry will not be there, because there will be small laboratories all over Europe. There will be hospitals where patients get the biopsy. Material is reseeded with e.g. chondrocytes, skin cells already. Once the midterm results on tissue engineered heart valves are turning optimistic, I think this concept will fly. So the industry I think has to change their concept of providing optimal implants for the patient.
Dr F. Mohr (Leipzig, Germany): Axel (Axel Haverich), I am not an expert, but I would be interested on the left side. You were mentioning that it does work with a tissue engineered valve on the right side, which I can see, but how is the situation right now in the high pressure system?
Dr Haverich : You have certainly followed one of the implant studies in Australia. I knew that valve. When I got the first notice that there were five patients implanted I felt at that point the stability of that graft was not good enough to withstand the pressure on the left side of the heart.
There are two experimental series now underway with tissue engineered grafts. Gino (Gino Gerosa), I don't know what you are doing, but Gustav Steinhoff in Rostock has done animal experiments now, they have not been sacrificed yet, with aortic valve replacement, and the same is true for Hoerstrup in Zurich. He also has done the first implants now on the aortic side. So, we have to see.
But even if we get it for the right side and we can show that they will last forever, well, there are very, very good arguments for it, because after six months there is no foreign material left in that valve. If we have very good midterm results on the right side, I think the first shift will be to do more Ross procedures, and then in a later stage go to the left side.
Mr B. Keogh (Birmingham, UK): Axel, may I please ask what the time scale is from knowing that someone needs a heart valve to actually being able to produce one that is tissue engineered?
Dr Haverich : Four weeks.
Mr Keogh : And may I just make a separate comment with respect to the working groups. The Council have been discussing for some time now how to take forward an agenda through EACTS on promoting research, development and innovation, and I think if people have ideas on that they should be discussed now, by ‘now’ I mean at this meeting, but I don't think we should come to any decision on firmly how to structure that, and I would suggest that we take it back to the Council and also through Dietrich's (Dietrich Birnbaum) research committee, and your suggestions, and a number of people have made these suggestions, are very welcome, and I think it is just the sort of corporate thing we should be doing.
And indeed, I also welcome your comment that other organizations are doing that, in particular, the European Society of Cardiology, and some of this research here, they already have groups addressing it, and there may even be room, if people feel it appropriate, for us to join forces in some areas.
Dr Haverich : Can I just reinforce that even more? I happened to be in Breslau, Poland, at the time where the working group, I repeat, the working group of the European Society of Cardiology on heart failure had its annual meeting. There were 2500 participants. When they first started six years ago, there were like 20 people. And they are discussing getting their own journal, they have their own guidelines and so on. And this is what I meant, we have to also be politically a bit more active in those fields where we find that there is a future for our Society. I think we need to develop political activities as well.
Dr L. Bockeria (Moscow, Russia): The American College of Surgeons also have a very good program for that. So maybe we have to study the experience they have and follow them.
Mr Keogh : May I just ask people whether they feel that working together with the cardiologists is appropriate? You have used an example of one of their working groups. Another very good one that started with only about 12 people was their working group on heart failure, which is now, as you say, hundreds of people and has its own journal. Do people feel that it is an appropriate way forward to work with our cardiological colleagues in some of these areas?
Dr Haverich : If I may comment, I think we should separate the issues for the various fields we are talking about. In some fields it may be very appropriate to immediately start working with them together, in other fields we might get our own ideas on paper and structure it first.
Dr T. Gardner (Philadelphia, Pennsylvania): The American Heart Association is an interesting professional organization, and is very devoted to supporting research and education. There is a Surgery Council, and that arrangement works very well in an association which is predominantly comprised of cardiologists and cardiac basic scientists. Surgeons do, in fact, participate fully in the activities of the American Heart. I will be serving as chair of their program committee for the next two years, which is a good indication that they integrate non-cardiologists if surgeons are there and actively participating.
Someone remarked earlier this morning we surgeons have not participated in many important professional ventures, perhaps because we have allowed ourselves to get so busy with our clinical practices and in our own fairly narrow areas. I would encourage you to think along those lines. The European Society of Cardiology is quite a strong organization and it would do well to have more surgeon participation.
Dr Haverich : Marko (Marko Turina) has been chairman of the working group of cardiac surgery within the European Society of Cardiology. Others here in the room have also been active. But usually during the meeting of the ESC there may be, at the most, five surgeons there simultaneously. They come in, go out, but they are not really interested. Nobody actually has taken some action in concentrating the work force on cardiac surgery within that cardiologic society.
Dr M. Turina (Zurich, Switzerland): I can say that my experience with The European Society of Cardiology was that there was never really true interest to integrate us. There have been several offers for a joint meeting of the EACTS with the European Society of Cardiology. At that time the EACTS council was against this idea, because we represent such a small minority in the total number of participants, so that we would just disappear in this huge meeting. That is probably the reason why the cardiac surgeons do not attend the meeting of the ESC, and therefore we don't have much to say in the ESC.
Dr Kappetein : How I envision this is with the working groups, you can have a working group, for example, on atrial fibrillation, aortic stents, biotechnology, left ventricular geometry. During the annual meeting you could have certain working groups on these subjects and everybody who is interested can go to a meetingroom and sit together and discuss how to direct research in a special field? There are many surgeons who want to perform research but their patient population is too small or they do not have enough reseources. You can also have industry the industry involved. So if you organize this on the Saturday afternoon during the annual meeting, you can also have the industry involved because there are already there for the techno college meeting. They could join the working group, and we could see how we can work together, and how to get funding. But I think that it's not a question, if we want to do it, we have to do it, at least if we want to give a new spirit to our Society and to our profession.
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Footnotes |
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Presented at the EACTS Symposium for the Future of Cardiac Surgery, Frankfurt, Germany, July 1–2, 2004. |
References |
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TopAbstract1. Current practice2. Drivers for change3. Options for progress4. Key issuesAppendixReferences |
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