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Ann Thorac Surg 1995;60:976-977
© 1995 The Society of Thoracic Surgeons
DR JOHN E. MAYER, JR (Boston, MA): I enjoyed this paper very much, and I thought it was exceedingly well presented. I believe the conclusions that the authors have reached on the basis of their experience are correct, and my colleagues and I would certainly agree with them that for patients with single ventricle and obstruction to systemic blood flow, the best time to relieve the intracardiac obstruction is in the newborn period. In reviewing a similar group of patients from our institution who all had single left ventricles, we drew almost identical conclusions. It is clear, we think, that an approach of bypassing the subaortic obstruction with either a pulmonary artery--aortic anastomosis or a palliative arterial switch is the approach to be taken.
In the more global sense, I think it is critical that when comparing various surgical management plans for patients with single ventricle, we look at long-term outcome, not just at whether or not the patient survived a neonatal hospitalization. As Dr Serraf has clearly pointed out, the important thing is what happens to the patients down the road, how many of them get to a Fontan procedure and how many of them survive that procedure. Much of that determination is going to depend on the quality of care and the approach during the neonatal period.
I think the last great challenge, if you will, in congenital heart surgery is managing patients with single ventricle. The results from our institution and other centers have a long way to go to reach a perfect outcome, but it is very important for us as congenital heart surgeons to focus on this particular group of patients.
The only question that occurred to me when I was reviewing the manuscript is the incidence of atrioventricular concordance. In our institutional experience, a large number of these patients have l-transposition or l-looped ventricles, implying atrioventricular discordance. I wonder if some exclusion criteria were employed or whether the patient population in France is different from that in New England.
I enjoyed the presentation very much, and I think it raises an absolutely critical issue for congenital heart surgeons. I congratulate you on your presentation and your results.
DR JOHN J. LAMBERTI (San Diego, CA): I compliment you for an excellent presentation. Your conclusions fit the data you had. However, I think there is an alternative approach.
Not every patient has critical subaortic obstruction or arch hypoplasia in infancy. My associates and I believe that it is equally important to reduce volume and pressure overloads on the ventricle. Although Dr Freedom has long said that banding increases subaortic stenosis, we believe that short-term banding is probably not harmful in patients who have minimal to mild anatomic subaortic obstruction. Our goal is to do an early bidirectional Glenn anastomosis. We believe that short-term banding controls pulmonary overperfusion. A bidirectional Glenn anastomosis and a Damus procedure done between 3 and 6 months of age converts the patient to a setting where the ventricular mass is relieved of both pressure and volume overloads.
When patients who are banded for an average of 48 months come to the Fontan operation, they are going to be in a high-risk group because of diastolic dysfunction. My suggestion is that pulmonary artery banding not be abandoned, but that a patient be unbanded before the age of 4 or 5 months under almost all circumstances and that a Damus connection be added when appropriate.
My question is, How old were the group I patients at the next stage? Were most of them 3 to 4 years of age? What impact did that have on outcome?
DR WILLIAM G. WILLIAMS (Toronto, ON, Canada): I enjoyed this presentation very much. You have identified a very important area of considerable difficulty. I have a question about the arterial switch operation. There are theoretical advantages to a switch rather than the Norwood approach. Those theoretical advantages seem to be outweighed by the difficulty of controlling pulmonary blood flow. Could you enlarge on your position regarding the present use of the arterial switch operation? Have you abandoned it for this entity?
DR SERRAF: I thank all the discussants. In regard to Dr Mayer's question, the only criterion of exclusion was the hypoplastic left heart syndrome. We wanted to include in the series all patients with so-called single-ventricle physiology, and this meant also patients with atrioventricular concordance and some types of atrioventricular canal and subaortic stenosis but a diminutive left ventricular cavity as well as patients with double-outlet right ventricle, mitral stenosis, and restrictive ventricular septal defect. Maybe that is why there are some patients with that kind of concordance.
Doctor Lamberti, we are well aware that some teams are still doing pulmonary artery banding with a very short interval of observation of what happens in the subaortic areas. We prefer to perform a radical operation at the first-stage operation when there is very severe aortic arch hypoplasia, but we still believe that the band should not be abandoned in this group of patients. In patients without hypoplasia of the transverse arch, we opt for aortic coarctation repair, pulmonary artery banding, and very close observation of the patient, and probably when the patient is 6 months of age, we perform a bidirectional Glenn operation. However, we keep in mind that the subaortic area is at risk to develop a subaortic stenosis and have a strong indication for bypassing it, namely, the presence of a 20 mm Hg gradient at rest.
Age at the second operation in group I was less than 1 year in 50% of the patients and between 2 and 3 years in the other half of the group. Maybe that is why some of the patients underwent a Fontan operation in association with a technique to alleviate the subaortic stenosis and why the other part of the group, ie, the younger patients, underwent only a bidirectional Glenn operation or a Blalock-Taussig shunt.
Doctor Williams, we strongly believe that the palliative arterial switch operation has theoretical advantages that rely on the physiology of the coronary circulation. Because the coronary arteries are relocated in the adjacent sinuses of Valsalva, there might be a more physiologic coronary flow and therefore better myocardial perfusion. Although we have no data to confirm this hypothesis, intuitively we believe that the coronary flow in a Stansel anastomosis or a Norwood operation is rather far from the basic coronary flow because it is retrograde, and therefore myocardial perfusion should be less than optimal.
In regard to balancing pulmonary and systemic circulation, when we started this series with the palliative arterial switch operation, we believed that the subaortic stenosis, which was converted to a subpulmonary stenosis, was enough to provide a sufficient flow for the pulmonary circulation. However, all of our patients at that time required a Blalock-Taussig shunt, which converted those patients with two sources of pulmonary artery blood flow; it was therefore quite difficult to obtain a good balance. At present, we still believe that if an arterial switch operation has to be performed because of a theoretical advantage for the coronary circulation, the neo--pulmonary artery valve and pathway must be closed and the pulmonary artery circulation supplied by only a single source of blood flow, namely, by a Blalock-Taussig shunt.
Finally, we have found in the pulmonary artery--aorta anastomosis, namely, the Stansel anastomosis, that when we have performed the Lamberti modification with a split in the sinuses of Valsalva, we can achieve the same type of coronary circulation as in a palliative arterial switch operation. This surgical technique is simpler than the palliative arterial switch.
Related Article
Ann. Thorac. Surg. 1995 60: 970-976.
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