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Recent results after repair of atrioventricular canal
Recent results after repair of atrioventricular canal Twelve patients with the complete form of persistent atrioventricular (AV) canal were operated upon at the University of Wisconsin between May, 1972, and November, 1975. The technique originally described by Rastelli and his associates was used. All 12 patients are asymptomatic and well, with no hospital or late deaths. Postoperative cardiac catheterization in 8 patients showed a return to near normal dynamics, with minimal residual mitral insufficiency. Half of these children had type A and half type C malformations; both types could be repaired without the need for valve replacement. Since 3 of these patients were less than 2 years of age, we now feel that complete repair of the AV canal can be undertaken in children between 12 and 18 months of age for optimal management.
Donald R. Kahn, M.D., Jay Levy, M.D., Nancy E. France, M.D., Kyung J. Chung, M.D., and Guillermo C. Dacumos, M.D., Madison, Wis.
\_J ntil recently, the surgical mortality rate for complete repair of atrioventricular (AV) canal was more than 60 per cent. 1-3 In the search to improve these dismal results, Castaneda and associates4 suggested, among other alternatives, a more extensive surgical procedure consisting of the replacement of the mitral valve. In 1968, a new technique5 was developed for the complete repair of AV canal that markedly improved the long-term prognosis and significantly decreased the surgical mortality rate. In this report, we describe our experience with this new technique in the complete repair of AV canal in twelve consecutive children during the past four years. Methods During the period from May, 1972, to November, 1975, 12 children ages 17 months to 15 years were operated upon for the complete repair of an AV canal. There were 7 girls and 5 boys. Three children were under the age of 2, but most were 3 to 4 years old. Most of the patients had severe symptoms of heart failure. In addition, one patient had a patent ductus arteriosus, From the Department of Surgery, Division of Thoracic and Cardiovascular Surgery, and the Department of Pediatrics, University of Wisconsin Medical Center, Madison, Wis. 53706. Received for publication Aug. 16, 1976. Accepted for publication Oct. 21, 1976. Address for reprints: Donald R. Kahn, M.D., University of Wisconsin Hospitals, Department of Surgery, 1300 University Ave., Madison, Wis. 53706.
another patient had infundibular pulmonary stenosis, and 4 patients had previous pulmonary artery banding. All patients had cardiac catheterizations. Right ventricular pressures were equal to the left ventricular pressures in 10 of the 12 patients and were significantly elevated in the other 2. Pulmonary hypertension was present in all of the patients, except in those who had previously undergone pulmonary artery banding and in the one child who had associated infundibular pulmonary stenosis. Pulmonary vascular resistance ranged from 2.6 to 10 resistance units. A left ventricular angiogram performed on all patients demonstrated the characteristic goose-neck elongation of the left ventricular outflow tract owing to mitral valve malformation and moderate-to-severe mitral insufficiency. It was not possible to determine definitely whether the AV canal was type A, B, or C from the left ventricular angiogram. Surgical technique The operation was performed through the median sternotomy incision with cardiopulmonary bypass. The procedure performed was described by Rastelli and associates5 and was carried out through a right atriotomy incision. The initial step in the repair is the approximation of the mitral components of the common leaflets with interrupted sutures. The anterior common leaflet was incised from the free margin to the annulus along mitral and tricuspid portions, regardless of whether the leaflet was undivided and unattached to the ventricular 413
The Journal of Thoracic and Cardiovascular Surgery
4 1 4 Kahn et al.
septum, as is true in type C, or attached to the septum by chordae, but incompletely divided, as is true in type A.8 In a similar manner, the posterior common leaflet was divided if the ventricular septal defect extended under this part of the leaflet. A single Teflon patch conforming to the shape of the ventriculo-atrial septal defect was used. The patch was joined to the right side of the ventricular septum with interrupted mattress sutures. Care was taken to place these sutures 3 to 5 mm. on the right ventricular side of the rim of the ventricular septal defect to avoid injuring the conduction system. All of these sutures were placed before lowering the patch into position and tying the sutures. In the type C variety, the mitral margin and the septal tricuspid margin of the incised anterior and posterior common leaflets are sutured onto the patch to the same plane as the normal mitral and tricuspid annulus. This is usually approximately 1 or 2 cm. above the lower rim of the patch. In AV canal type A, the anterior portion of the septal leaflet of the tricuspid valve is frequently absent, so that only the mitral side of the anterior leaflet can be attached to the patch. Apparently, tricuspid insufficiency does not result. Finally, the atrial portion of the septal defect is closed by a continuous suture, with the cephalad portion of the patch being attached to the rim of the atrial septum. The patient ductus arteriosus in the one patient was ligated. In another patient, the infundibular obstruction of the right ventricular outflow was resected through a right ventriculotomy. The pulmonary artery bands in 4 patients were excised in a circumferential manner, with a small posterior rim left. The pulmonary artery was then reanastomosed. Results Of the 12 children, 6 had type A and 6 had type C malformations. All 12 patients are asymptomatic and clinically well. There were no operative or late deaths. None of the children have had heart block. Eight of the patients have had recatheterization studies 6 months to one year postoperatively. The pulmonary artery and right ventricular pressures varied between 20 and 40 mm. Hg. In 7 patients, there was no residual shunt; one had a small residual ventricular septal defect. Pulmonary vascular resistance had returned to normal in all the patients. In a 17-month-old child, who had the highest preoperative resistance (10 resistance units), a pulmonary artery pressure of 90 mm. Hg, and a left-to-right shunt of only 1.3:1, postoperative vascular resistance dropped to 2.2 resistance units, with pulmonary artery pressures of 35 mm. Hg and no residual shunt. The left ventricular angiogram showed
either mild or no mitral insufficiency in all 8 patients. No systolic gradient was measured across the left ventricular outflow tract. There was no significant difference in the postoperative results, including the amount of mitral insufficiency, between the type A and the type C AV canal. Discussion The new technique that was used on the patients in this paper, as originally described by Rastelli, Ongley, Kirklin, and McGoon,5 has revolutionized the prognosis, both early and late, for the repair of AV canal. Before the development of the present technique, the common anterior leaflet was sutured to the ventricular septum to obliterate the ventricular communication in this area. This procedure obstructed the left ventricular outflow tract and deformed the mitral valve to such a degree as to produce more mitral insufficiency. The present technique, consisting of reattaching the valve structures to the patch at the normal anatomic position, leaves an adequate left ventricular outflow tract and allows adequate valve function. In none of the patients was a valve replacement necessary, and no patient had more than mild mitral insufficiency postoperatively. Some of these valves can be severely deformed with fenestrations and thickening, as well as the usual cleft, particularly in older children. These valves can be pieced together by closing the fenestrations and suturing the cleft to make them function adequately. With the old technique and even with the present technique, some authors have found that a type C free-floating valve is more difficult to repair adequately. We found the opposite to be true, since the valvular tissue in the type C malformation is less severely deformed and easier to repair than that in type A. It seems unnecessary to us for a valve replacement to be considered in the usual anatomic pattern of either type A or type C AV canal. Recent studies have shown that significant pulmonary vascular disease develops with AV canal after the age of 2 years.7 Our youngest patient was 17 months old and only 3 children in this series were younger than 2 years of age, but their repairs were no more difficult or complicated than in the older children. In fact, the most dramatic change in the pulmonary vascular resistance was seen in our youngest patient. It is our present policy, therefore, to plan a complete repair of the AV canal at 12 to 18 months of age in order to prevent permanent pulmonary vascular changes and to provide earlier relief of the problems related to the congestive failure.
Volume 73 Number 3 March, 1977
REFERENCES 1 Levy, M. J., Cuello, L., Tuna, N., et al.: Atrioventricularis Communis: Clinical Aspects of Surgical Treatment, Am. J. Cardiol. 14: 587, 1964. 2 Scott, L. P., Hauck, A. J., Nadas, A., et al.: Endocardial Cushion Defect: Preoperative and Postoperative Surgery, Circulation 26: 218, 1962. 3 Ellis, F. H., Jr., McGoon, D. C , and Kirklin, J. W.: Surgical Management of Persistent Common Atrioventricular Canal, Am. J. Cardiol. 6: 598, 1960. 4 Castaneda, A. R., Nicoloff, D. M., Moller, J. H., and Lucas, R. V., Jr.: Surgical Correction of Complete Atrioventricular Canal Utilizing Ball-Valve Replacement of
Repair of atrioventricular
canal
415
the Mitral Valve, J. THORAC. CARDIOVASC. SURG. 62:
926, 1971. 5 Rastelli, G. C , Ongley, P. A., Kirklin, J. W., and McGoon, D. C : Surgical Repair of the Complete Form of Persistent Common Atrioventricular Canal, J. THORAC. CARDIOVASC. SURG. 55: 299,
1968.
6 Rastelli, G. C , Kirklin, J. W., and Titus, J. L.: Anatomic Observations of Complete Form of Persistent Common Atrioventricular Valves, Mayo Clin. Proc. 41: 296, 1966. 7 Newfeld, E. A., Sher, M., Paul, M. H., et al.: Pulmonary Vascular Disease in Complete Atrioventricular Canal (Abstr.), Am. J. Cardiol. 37: 159, 1976.
Donald R. Kahn, M.D., Jay Levy, M.D., Nancy E. France, M.D., Kyung J. Chung, M.D., and Guillermo C. Dacumos, M.D., Madison, Wis.
\_J ntil recently, the surgical mortality rate for complete repair of atrioventricular (AV) canal was more than 60 per cent. 1-3 In the search to improve these dismal results, Castaneda and associates4 suggested, among other alternatives, a more extensive surgical procedure consisting of the replacement of the mitral valve. In 1968, a new technique5 was developed for the complete repair of AV canal that markedly improved the long-term prognosis and significantly decreased the surgical mortality rate. In this report, we describe our experience with this new technique in the complete repair of AV canal in twelve consecutive children during the past four years. Methods During the period from May, 1972, to November, 1975, 12 children ages 17 months to 15 years were operated upon for the complete repair of an AV canal. There were 7 girls and 5 boys. Three children were under the age of 2, but most were 3 to 4 years old. Most of the patients had severe symptoms of heart failure. In addition, one patient had a patent ductus arteriosus, From the Department of Surgery, Division of Thoracic and Cardiovascular Surgery, and the Department of Pediatrics, University of Wisconsin Medical Center, Madison, Wis. 53706. Received for publication Aug. 16, 1976. Accepted for publication Oct. 21, 1976. Address for reprints: Donald R. Kahn, M.D., University of Wisconsin Hospitals, Department of Surgery, 1300 University Ave., Madison, Wis. 53706.
another patient had infundibular pulmonary stenosis, and 4 patients had previous pulmonary artery banding. All patients had cardiac catheterizations. Right ventricular pressures were equal to the left ventricular pressures in 10 of the 12 patients and were significantly elevated in the other 2. Pulmonary hypertension was present in all of the patients, except in those who had previously undergone pulmonary artery banding and in the one child who had associated infundibular pulmonary stenosis. Pulmonary vascular resistance ranged from 2.6 to 10 resistance units. A left ventricular angiogram performed on all patients demonstrated the characteristic goose-neck elongation of the left ventricular outflow tract owing to mitral valve malformation and moderate-to-severe mitral insufficiency. It was not possible to determine definitely whether the AV canal was type A, B, or C from the left ventricular angiogram. Surgical technique The operation was performed through the median sternotomy incision with cardiopulmonary bypass. The procedure performed was described by Rastelli and associates5 and was carried out through a right atriotomy incision. The initial step in the repair is the approximation of the mitral components of the common leaflets with interrupted sutures. The anterior common leaflet was incised from the free margin to the annulus along mitral and tricuspid portions, regardless of whether the leaflet was undivided and unattached to the ventricular 413
The Journal of Thoracic and Cardiovascular Surgery
4 1 4 Kahn et al.
septum, as is true in type C, or attached to the septum by chordae, but incompletely divided, as is true in type A.8 In a similar manner, the posterior common leaflet was divided if the ventricular septal defect extended under this part of the leaflet. A single Teflon patch conforming to the shape of the ventriculo-atrial septal defect was used. The patch was joined to the right side of the ventricular septum with interrupted mattress sutures. Care was taken to place these sutures 3 to 5 mm. on the right ventricular side of the rim of the ventricular septal defect to avoid injuring the conduction system. All of these sutures were placed before lowering the patch into position and tying the sutures. In the type C variety, the mitral margin and the septal tricuspid margin of the incised anterior and posterior common leaflets are sutured onto the patch to the same plane as the normal mitral and tricuspid annulus. This is usually approximately 1 or 2 cm. above the lower rim of the patch. In AV canal type A, the anterior portion of the septal leaflet of the tricuspid valve is frequently absent, so that only the mitral side of the anterior leaflet can be attached to the patch. Apparently, tricuspid insufficiency does not result. Finally, the atrial portion of the septal defect is closed by a continuous suture, with the cephalad portion of the patch being attached to the rim of the atrial septum. The patient ductus arteriosus in the one patient was ligated. In another patient, the infundibular obstruction of the right ventricular outflow was resected through a right ventriculotomy. The pulmonary artery bands in 4 patients were excised in a circumferential manner, with a small posterior rim left. The pulmonary artery was then reanastomosed. Results Of the 12 children, 6 had type A and 6 had type C malformations. All 12 patients are asymptomatic and clinically well. There were no operative or late deaths. None of the children have had heart block. Eight of the patients have had recatheterization studies 6 months to one year postoperatively. The pulmonary artery and right ventricular pressures varied between 20 and 40 mm. Hg. In 7 patients, there was no residual shunt; one had a small residual ventricular septal defect. Pulmonary vascular resistance had returned to normal in all the patients. In a 17-month-old child, who had the highest preoperative resistance (10 resistance units), a pulmonary artery pressure of 90 mm. Hg, and a left-to-right shunt of only 1.3:1, postoperative vascular resistance dropped to 2.2 resistance units, with pulmonary artery pressures of 35 mm. Hg and no residual shunt. The left ventricular angiogram showed
either mild or no mitral insufficiency in all 8 patients. No systolic gradient was measured across the left ventricular outflow tract. There was no significant difference in the postoperative results, including the amount of mitral insufficiency, between the type A and the type C AV canal. Discussion The new technique that was used on the patients in this paper, as originally described by Rastelli, Ongley, Kirklin, and McGoon,5 has revolutionized the prognosis, both early and late, for the repair of AV canal. Before the development of the present technique, the common anterior leaflet was sutured to the ventricular septum to obliterate the ventricular communication in this area. This procedure obstructed the left ventricular outflow tract and deformed the mitral valve to such a degree as to produce more mitral insufficiency. The present technique, consisting of reattaching the valve structures to the patch at the normal anatomic position, leaves an adequate left ventricular outflow tract and allows adequate valve function. In none of the patients was a valve replacement necessary, and no patient had more than mild mitral insufficiency postoperatively. Some of these valves can be severely deformed with fenestrations and thickening, as well as the usual cleft, particularly in older children. These valves can be pieced together by closing the fenestrations and suturing the cleft to make them function adequately. With the old technique and even with the present technique, some authors have found that a type C free-floating valve is more difficult to repair adequately. We found the opposite to be true, since the valvular tissue in the type C malformation is less severely deformed and easier to repair than that in type A. It seems unnecessary to us for a valve replacement to be considered in the usual anatomic pattern of either type A or type C AV canal. Recent studies have shown that significant pulmonary vascular disease develops with AV canal after the age of 2 years.7 Our youngest patient was 17 months old and only 3 children in this series were younger than 2 years of age, but their repairs were no more difficult or complicated than in the older children. In fact, the most dramatic change in the pulmonary vascular resistance was seen in our youngest patient. It is our present policy, therefore, to plan a complete repair of the AV canal at 12 to 18 months of age in order to prevent permanent pulmonary vascular changes and to provide earlier relief of the problems related to the congestive failure.
Volume 73 Number 3 March, 1977
REFERENCES 1 Levy, M. J., Cuello, L., Tuna, N., et al.: Atrioventricularis Communis: Clinical Aspects of Surgical Treatment, Am. J. Cardiol. 14: 587, 1964. 2 Scott, L. P., Hauck, A. J., Nadas, A., et al.: Endocardial Cushion Defect: Preoperative and Postoperative Surgery, Circulation 26: 218, 1962. 3 Ellis, F. H., Jr., McGoon, D. C , and Kirklin, J. W.: Surgical Management of Persistent Common Atrioventricular Canal, Am. J. Cardiol. 6: 598, 1960. 4 Castaneda, A. R., Nicoloff, D. M., Moller, J. H., and Lucas, R. V., Jr.: Surgical Correction of Complete Atrioventricular Canal Utilizing Ball-Valve Replacement of
Repair of atrioventricular
canal
415
the Mitral Valve, J. THORAC. CARDIOVASC. SURG. 62:
926, 1971. 5 Rastelli, G. C , Ongley, P. A., Kirklin, J. W., and McGoon, D. C : Surgical Repair of the Complete Form of Persistent Common Atrioventricular Canal, J. THORAC. CARDIOVASC. SURG. 55: 299,
1968.
6 Rastelli, G. C , Kirklin, J. W., and Titus, J. L.: Anatomic Observations of Complete Form of Persistent Common Atrioventricular Valves, Mayo Clin. Proc. 41: 296, 1966. 7 Newfeld, E. A., Sher, M., Paul, M. H., et al.: Pulmonary Vascular Disease in Complete Atrioventricular Canal (Abstr.), Am. J. Cardiol. 37: 159, 1976.