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Ann Thorac Surg 1995;60:282-283
© 1995 The Society of Thoracic Surgeons
DR CARLOS BLANCHE (Los Angeles, CA): I congratulate Dr Bittner on this most elegant animal study. This is not a new technique for orthotoptic heart transplantation, however, as it was described by Cass and Brock in England in 1959 and in the United States by Webb in the same year. It was introduced into clinical practice by Professor Gilles Dreyfus in 1991. Since October 1991 we have used this new complete atrioventricular technique for all our orthotopic heart transplantations, and to date we have performed 80 such transplantations.
We have seen significant hemodynamic improvement in our patients postoperatively, including a decreased incidence of mitral and tricuspid regurgitation, and we have basically eliminated the need for pacemaker implantation in the posttransplantation period.
There is a disadvantage to this alternative technique, however, and that is that it takes longer to perform. In our experience the ischemic time is prolonged by an average of 21 minutes. I agree with Dr Bittner that this is a more physiologic approach because there is no distortion of the atrium and it preserves the geometric configuration and anatomic size of the right and left atria.
DR BITTNER: Thank you, Dr Blanche. This technique actually was described in 1953 by Neptune, and also Drs Lower and Shumway have been very well aware of this technique. At that time, unfortunately, they did not proceed with extensive study of orthotopic transplantation because of the prolonged bypass times you just mentioned you have encountered in your patients. Sewing the anastomoses in a different order like the one I described might reduce the ischemic time. You can shorten the total ischemic time by doing the superior vena cava anastomosis last upon the release of the cross-clamp, but with the modern techniques and with the advances in cardiac graft preservation, a slightly prolonged ischemic time is tolerable. I congratulate you that you have been so aggressive in applying this technique, which was introduced into clinical use by the very innovative Carpentier group in France.
DR NORMAN A. SILVERMAN (Detroit, MI): In 1994 and 1995 we have started to do a lot of heart transplantations with second, third, and fourth sternotomies. It seems to me that this technique would involve a little more difficult digging out of the fragile venous structures and doing individual anastomoses. We are kind of lucky to find the heart and chisel it away and leave something to sew to. Do you want to comment on that?
DR BITTNER:
I have been struck by the fact that this new technique has been introduced into clinical practice without going through the experimental laboratory, and at this time I would not say that new is always better. It is very easy to do these studies in a canine model; you only hurt your budget but not so much the patient. In patients especially, you get a little bit nervous if you see a very short stump of inferior vena cava and you then are forced to anastomose that to the remaining inferior vena cava of the donor heart. It is challenging. But, as Dr Blanche taught us, it is possible and has been possible already in 80 patients.
DR STEVEN F. BOLLING (Ann Arbor, MI): I enjoyed your paper very much. I have two questions. Because this is an acute study, do you think that the differences in the return of normal sinus rhythm would stand up in the long term? We see many patients in whom the standard technique has been used come off bypass, not in normal sinus rhythm; almost all of them regain long-term normal sinus rhythm.
Second, do you have Doppler echocardiographic quantitation of atrioventricular valve regurgitation? Is some of this effect due to differences in tricuspid valve regurgitation?
DR BITTNER: Thank you, Dr Bolling. The next step in our laboratory is certainly to perform long-term studies, and we have to wait for the recurrence of sinus node recovery. I assume I insert at various times in the sinus node area. In addition meticulous care was taken not to do too many manipulations in the sinoatrial junction.
Further studies will certainly include color-flow Doppler echocardiography. We used only a very old 5-MHz probe, and I am not good at echocardiography, but at least I was able to get wall thickness and left ventricular volume. This is important for us to rule out an increase in wall thickness resulting from edema, which might alter our functional assessment.
DR GILLES D. DREYFUS (Paris, France): I congratulate you on this paper. I did publish in 1991 in The Annals of Thoracic Surgery a description of the technique you described and the experience in the first 7 patients. Since then we have done more than 50 such procedures, and I confirm Dr Blanche's observation that this technique is perfectly feasible.
I think it is very difficult to prove the hemodynamic superiority of one technique over another because by doing experimental work you elude all the problems resulting from recipient status, such as pulmonary vascular resistances, ischemic time, and weight mismatch between donor and recipient. I think it is more a morphologic technique, as you avoid valvular regurgitation, bulging sutures of the atria, and aneurysmal movements of the recipient's atria, which you encounter with the standard technique.
Another problem that has been well shown by Angermann in a previous publication describing the use of transesophageal echocardiography is that you do not have these bulging suture lines, which are the source of some emboli. Because thrombus formation in the suture line has recently been noted in many transplant recipients who have undergone transesophageal echocardiography, this is also another advantage of the technique.
Concerning the sinus rhythm, we have not had any patients requiring pacemakers as a result of this technique. I think that the ability to keep patients in sinus rhythm which this technique makes possible is probably more important than the hemodynamic benefits, which still remain to be demonstrated.
DR VERDI J. DiSESA (Philadelphia, PA): A technique that mainly modifies how you handle the atrium seems to affect the function of the right ventricle. Do you have any speculation as to why that might be?
Second, how do you do this technique when the donor also supplies two lungs and pieces of atrium?
DR BITTNER: The second question is, fortunately, easier to answer. I think if multiple organs are being harvested and the lungs are going to different transplant centers, you can make the preliminary venous Carrel patches a little bit larger in the mediastinum of the recipient; you gain tissue there. It is doable. One might also consider combining a standard left atrioplasty with separate superior and inferior venae cavae anastomoses on the right side.
My colleague, Dr Kendell, from Papworth Hospital, did a prospective, randomized study of this new technique. He also did not find any hemodynamic advantages in the short term, but what he really confirmed was that this technique is feasible even when organs are going to various centers.
As to the first question, what is the contribution of atrial function, or especially atrial systole, to the overall improvement in the hemodynamics; it is difficult to assess in the short term immediately after the termination of bypass. Long-term experiments with this technique and functional evaluation lasting longer after the termination of cardiopulmonary bypass would be required to get a clear answer to that. We measured hemodynamic function with regard to the contribution of atrial systole, and we did not find a significant increase in cardiac output, although there was a trend toward improvement.
DR DiSESA: But my question was really directed to the load-independent indices of right ventricular function. I do not want to prolong the discussion forever, but I think that that remains an open question.
Related Article
Ann. Thorac. Surg. 1995 60: 275-282.
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