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Classification of descending necrotizing mediastinitis
1296
CORRESPONDENCE
thoracotomy), heart rate and contractility, arterial PO2 and PCO2, acid-base status, hematocrit, and systemic and respiratory resistance. Several changes occur to all these variables with mutual interference, particularly within the first few hours after the operation. It is therefore very difficult to predict the effectiveness of a pulmonary artery banding, with the band applied in an almost instantaneous fashion, with the various factors (systemic and pulmonary artery pressure, systemic oxygen saturation) followed a few minutes before chest closure. Trusler’s formula [2], utilized to determine the length of the band for the individual patient, takes into account the body weight and the underlying malformation, and is obtained by analyzing the late results after the pulmonary artery banding. The rule is still used to avoid the problem of difficult regulation because of the instantaneous changes in systemic and pulmonary pressures once the band is applied around the main pulmonary artery. To overcome these difficulties, several attempts have been made to create an adjustable pulmonary banding, to allow for external regulation during the hours or days after the surgical procedure, once all the variables have become more stable [3–5]. Laks and associates [1] mention Trusler’s formula as the general guideline, because its application determines the final adjustment of the band upon observation of the monitored variables. At this point several questions are obvious: 1. Based on what assumption can Trusler’s formula be applied to a modified pulmonary artery in which the infolding wall has been resected, as in all cases utilized by Trusler for his calculations the infolding was present? 2. Why did Dr Laks decide to abandon his technique of adjustable pulmonary artery banding [3] after years of successful clinical application? In this regard, the previously utilized technique has not been mentioned in the presently published list of references. 3. Why are Laks and associates now proposing a new technique, without mentioning the current clinical experience (number of patients, diagnosis, results)? It is generally difficult for a surgeon to move from one technique to another. This process can occur only if the new technique is supported with justified criticism of the previous technique and at least preliminary results (either experimental or clinical) with the new one. Antonio F. Corno, MD Cardiac Surgery Centre Hospitalier Universitaire Vaudois rue du Bugnon 46 1011 Lausanne, Switzerland
References 1. Laks H, Odim JN, Sadeghi AM, Allada V. The incisional pulmonary artery band. Ann Thorac Surg 1999;67:1813– 4. 2. Trusler GA, Mustard WT. A method of banding the pulmonary artery for large isolated ventricular septal defect with and without transposition of the great arteries. Ann Thorac Surg 1972;13:351–5. 3. Dajee H, Benson L, Laks H. An improved method of pulmonary artery banding. Ann Thorac Surg 1984;37:254–7. 4. Vince DJ, Culham JAG, LeBlanc JG, Taylor GP. A dilatable prosthesis for banding the pulmonary artery: initial clinical experience. J Thorac Cardiovasc Surg 1992;103:392–3. 5. Schlensak C, Sarai K, Gildein HP, Beyersdorf F. Pulmonary artery banding with a novel percutaneously, bidirectional adjustable device. Eur J Cardiothor Surg 1997;12:931–3. © 2000 by The Society of Thoracic Surgeons Published by Elsevier Science Inc
Ann Thorac Surg 2000;69:1295–1302
Classification of Descending Necrotizing Mediastinitis To the Editor: We read with great interest the recent article by Marty-Ane´ and associates [1]. Descending necrotizing mediastinitis (DNM) is a rare but fatal disease. We congratulate them on their excellent results. Recently we proposed the simple classification of the degree of diffusion of DNM based on computed tomography [2]. Type I is localized in the upper mediastinum above the tracheal bifurcation and may not always require aggressive mediastinal drainage. Type IIA extends to the lower anterior mediastinum. Type IIB extends to the anterior and lower posterior mediastinum and demands complete mediastinal drainage with debridement by thoracotomy. We think subxiphoidal mediastinal drainage or thoracoscopic operation without sternotomy may provide adequate drainage in type IIA. We completely agree with the comment of Marty-Ane´ and colleagues regarding the causes of the high mortality rate in DNM. Delayed diagnosis and inadequate drainage are fatal. We believe our classification is of use for describing the degree of DNM as well as for determining the treatment. Tsuyoshi Hasegawa, MD Shunsuke Endo, MD, PhD Yasunori Sohara, MD, PhD Department of Thoracic and Cardiovascular Surgery Jichi Medical School 3311-1 Yakushiji, Minamikawachi, Kawachi Tochigi 329-0498, Japan
References 1. Marty-Ane´ CH, Merthet JP, Alric P, Pegis JD, Rouviere P, Mary H. Management of descending mediastinitis: an aggressive treatment for an aggressive disease. Ann Thorac Surg 1999;68:212–7. 2. Endo S, Murayama F, Hasegawa T, et al. Guideline of surgical management based on diffusion of descending necrotizing mediastinitis. Jpn J Thorac Cardiovasc Surg 1999;47:14–9.
More About Obstructive Lesions of the Right Aortic Arch To the Editor: I read with interest the recent articles about obstructive lesions of the right aortic arch [1, 2]. Both articles did not review a rare and unique combination of anomalies—namely tetralogy of Fallot with coarctation of the aorta [3]. One article even explained, according to the flow-related development of the great arteries, why hypoplasia of the aortic isthmus is unlikely to develop in the presence of decreased or absent right-sided outflow tract [1]. However, seven such cases were reported by 1995, of which six had a right aortic arch. The two recent articles reviewed together 22 cases of right aortic arch with coarctation and situs solitus. Failure to include six published cases (21% of the total published experience) resulted in the lack of discussion of the possible pathogenetic mechanisms and the surgical implications of this particular combination. As demonstrated in our report [3], neither fetal hydrodynamic conditions nor ductal closure could explain the formation of coarctation in this rare association of anomalies. We proposed that external compression of the right-sided aorta during fetal life, by a retroaortic 0003-4975/00/$20.00
CORRESPONDENCE
thoracotomy), heart rate and contractility, arterial PO2 and PCO2, acid-base status, hematocrit, and systemic and respiratory resistance. Several changes occur to all these variables with mutual interference, particularly within the first few hours after the operation. It is therefore very difficult to predict the effectiveness of a pulmonary artery banding, with the band applied in an almost instantaneous fashion, with the various factors (systemic and pulmonary artery pressure, systemic oxygen saturation) followed a few minutes before chest closure. Trusler’s formula [2], utilized to determine the length of the band for the individual patient, takes into account the body weight and the underlying malformation, and is obtained by analyzing the late results after the pulmonary artery banding. The rule is still used to avoid the problem of difficult regulation because of the instantaneous changes in systemic and pulmonary pressures once the band is applied around the main pulmonary artery. To overcome these difficulties, several attempts have been made to create an adjustable pulmonary banding, to allow for external regulation during the hours or days after the surgical procedure, once all the variables have become more stable [3–5]. Laks and associates [1] mention Trusler’s formula as the general guideline, because its application determines the final adjustment of the band upon observation of the monitored variables. At this point several questions are obvious: 1. Based on what assumption can Trusler’s formula be applied to a modified pulmonary artery in which the infolding wall has been resected, as in all cases utilized by Trusler for his calculations the infolding was present? 2. Why did Dr Laks decide to abandon his technique of adjustable pulmonary artery banding [3] after years of successful clinical application? In this regard, the previously utilized technique has not been mentioned in the presently published list of references. 3. Why are Laks and associates now proposing a new technique, without mentioning the current clinical experience (number of patients, diagnosis, results)? It is generally difficult for a surgeon to move from one technique to another. This process can occur only if the new technique is supported with justified criticism of the previous technique and at least preliminary results (either experimental or clinical) with the new one. Antonio F. Corno, MD Cardiac Surgery Centre Hospitalier Universitaire Vaudois rue du Bugnon 46 1011 Lausanne, Switzerland
References 1. Laks H, Odim JN, Sadeghi AM, Allada V. The incisional pulmonary artery band. Ann Thorac Surg 1999;67:1813– 4. 2. Trusler GA, Mustard WT. A method of banding the pulmonary artery for large isolated ventricular septal defect with and without transposition of the great arteries. Ann Thorac Surg 1972;13:351–5. 3. Dajee H, Benson L, Laks H. An improved method of pulmonary artery banding. Ann Thorac Surg 1984;37:254–7. 4. Vince DJ, Culham JAG, LeBlanc JG, Taylor GP. A dilatable prosthesis for banding the pulmonary artery: initial clinical experience. J Thorac Cardiovasc Surg 1992;103:392–3. 5. Schlensak C, Sarai K, Gildein HP, Beyersdorf F. Pulmonary artery banding with a novel percutaneously, bidirectional adjustable device. Eur J Cardiothor Surg 1997;12:931–3. © 2000 by The Society of Thoracic Surgeons Published by Elsevier Science Inc
Ann Thorac Surg 2000;69:1295–1302
Classification of Descending Necrotizing Mediastinitis To the Editor: We read with great interest the recent article by Marty-Ane´ and associates [1]. Descending necrotizing mediastinitis (DNM) is a rare but fatal disease. We congratulate them on their excellent results. Recently we proposed the simple classification of the degree of diffusion of DNM based on computed tomography [2]. Type I is localized in the upper mediastinum above the tracheal bifurcation and may not always require aggressive mediastinal drainage. Type IIA extends to the lower anterior mediastinum. Type IIB extends to the anterior and lower posterior mediastinum and demands complete mediastinal drainage with debridement by thoracotomy. We think subxiphoidal mediastinal drainage or thoracoscopic operation without sternotomy may provide adequate drainage in type IIA. We completely agree with the comment of Marty-Ane´ and colleagues regarding the causes of the high mortality rate in DNM. Delayed diagnosis and inadequate drainage are fatal. We believe our classification is of use for describing the degree of DNM as well as for determining the treatment. Tsuyoshi Hasegawa, MD Shunsuke Endo, MD, PhD Yasunori Sohara, MD, PhD Department of Thoracic and Cardiovascular Surgery Jichi Medical School 3311-1 Yakushiji, Minamikawachi, Kawachi Tochigi 329-0498, Japan
References 1. Marty-Ane´ CH, Merthet JP, Alric P, Pegis JD, Rouviere P, Mary H. Management of descending mediastinitis: an aggressive treatment for an aggressive disease. Ann Thorac Surg 1999;68:212–7. 2. Endo S, Murayama F, Hasegawa T, et al. Guideline of surgical management based on diffusion of descending necrotizing mediastinitis. Jpn J Thorac Cardiovasc Surg 1999;47:14–9.
More About Obstructive Lesions of the Right Aortic Arch To the Editor: I read with interest the recent articles about obstructive lesions of the right aortic arch [1, 2]. Both articles did not review a rare and unique combination of anomalies—namely tetralogy of Fallot with coarctation of the aorta [3]. One article even explained, according to the flow-related development of the great arteries, why hypoplasia of the aortic isthmus is unlikely to develop in the presence of decreased or absent right-sided outflow tract [1]. However, seven such cases were reported by 1995, of which six had a right aortic arch. The two recent articles reviewed together 22 cases of right aortic arch with coarctation and situs solitus. Failure to include six published cases (21% of the total published experience) resulted in the lack of discussion of the possible pathogenetic mechanisms and the surgical implications of this particular combination. As demonstrated in our report [3], neither fetal hydrodynamic conditions nor ductal closure could explain the formation of coarctation in this rare association of anomalies. We proposed that external compression of the right-sided aorta during fetal life, by a retroaortic 0003-4975/00/$20.00