J Thorac Cardiovasc Surg 2007;134:1405
© 2007 The American Association for Thoracic Surgery
Surgery for Congenital Heart Disease |
Discussion
Dr Brian L. Reemtsen
(Los Angeles, Calif). I’d first like to congratulate the authors on an excellent presentation on a difficult subject. I have 3 questions in regard to your presentation. First, at our institution we have retrospectively reviewed all the patients that have undergone diaphragm plication after cardiac surgery, and we have observed that all patients have some return of function at 1 year. Did you notice any return of function in these affected diaphragms? At what time intervals, if any, did you look at the diaphragms? Do you think that this improved function could lead to better splanchnic hemodynamics?
Dr Hsia. As far as your question about interval diaphragmatic interrogation is concerned, a recent article from The Netherlands reports 4 (29%) of 14 patients who had previous diaphragm plication have return of appropriate diaphragmatic movement during follow-up.1
For this study, we enrolled patients with previous diaphragm plication, but without return of normal diaphragm function. Those with return of function noted from ultrasound interrogation were excluded from this study. For the 19 biventricular and Fontan patients studied with previous diaphragm plication, their affected diaphragm remained either immobile or fixated in place with no paradoxical motion under ultrasonographic interrogation.
Dr Reemtsen. My second question relates to the first one. In your manuscript you did not describe what method you used for plication. Could you briefly go through that and tell us whether you think that has any impact on possible return of function or splanchnic blood flow?
Dr Hsai. All diaphragm plications used a linear imbrication technique. This is also referred to as the accordion or central pleating method as described by Shoemaker and associates.2 Therefore, I cannot speculate whether different techniques of diaphragmatic plication can lead to differential return of diaphragmatic function or variably affect splanchnic venous flow dynamics.
Dr Reemtsen. Finally, you related that the patients with diaphragm paralysis have impaired splanchnic hemodynamics stemming from altered respiratory mechanics. You made the corollary that this may, in fact, lead to poor Fontan hemodynamics. My question is, did these 9 patients have poor Fontans with high pressures and increased incidence of ascites and protein-losing enteropathy?
Dr Hsia. This is a very good question. We believe the basis of this study’s significance is that our data shed light on a previously unknown consequence of phrenic nerve injury and diaphragm paralysis: that despite surgical plication, the flow dynamics is suboptimal. Because these suboptimal characteristics are similar to those seen in patients with failing Fontan circulation, those with a plicated diaphragm may be predisposed for earlier failure and thus benefit from a higher level of surveillance and clinical follow-up.
When this physiologic study was performed 6 years ago, none of the 9 Fontan patients had documented protein-losing enteropathy or elevated pressures. However, 1 was in NYHA class II and 3 were in class III. One patient in class III, or failing Fontan state, has since died. Unfortunately, we do not have information whether this patient had protein-losing enteropaathy or other gastrointestinal problems. All 19 of the patients who were in NYHA class I after the Fontan operation, with normal diaphragms, remain in class I since conclusion of the study.
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References
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- van Onna IE, Metz R, Jekel L, Woolley SR, van de Wal HJ. Post cardiac surgery phrenic nerve palsy: value of plication and potential for recovery. Eur J Cardiothorac Surg 1998;14:179-184.[Abstract/Free Full Text]
- Shoemaker R, Palmer G, Brown JW, King H. Aggressive treatment of acquired phrenic nerve paralysis in infants and small children. Ann Thorac Surg 1981;32:250-259.[Medline]
Related Article
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Subdiaphragmatic venous hemodynamics in patients with biventricular and Fontan circulation after diaphragm plication
- Tain-Yen Hsia, Sachin Khambadkone, Scott M. Bradley, and Marc R. de Leval
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