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Treatment of bulboventricular foramen stenosis by ventricle-ascending aorta valved-conduit bypass
CASE REPORTS
Treatment of Bulboventricular Foramen Stenosis by Ventricle-Ascending Aorta Valved-Conduit Bypass Morrison C . Bethea, MD, and James L. Reynolds, MD Southern Baptist Hospital, New Orleans, Louisiana
An 8-year-old girl with single ventricle and l-transposition developed severe stenosis of the bulboventricular foramen. This became critical subsequent to pulmonary banding and a modified Fontan operation. Successful relief of the obstruction was achieved by placing a valved conduit between the ventricle and ascending aorta, thus bypassing the obstruction. (Ann Tlzorac Surg 1989;47:765-6)
S
urgical relief of bulboventricular foramen (BVF) stenosis is difficult. We report an alternative technique for bypassing such an obstruction. The patient, an 8-year-old girl, had a heart murmur and cardiac failure at 7 weeks of age. Cardiac catheterization at that time showed a double-inlet, single ventricle with 1-transposition. A subaortic rudimentary outflow tract chamber was connected by way of an unrestrictive BVF to the single ventricle, and an unobstructed pulmonary artery arose directly from the ventricle. Because of intractable cardiac failure, the pulmonary artery was surgically banded when the infant was 3 months of age. She improved progressively, but by 4 years of age, cyanosis appeared. One year later, repeat catheterization showed the following pressure measurements (mm Hg): main pulmonary artery, 24/14; left atrium (mean), 8; left ventricular end-diastolic, 6.5 to 10.5; BVF gradient, 10. Pulmonary resistance was 1.6 units. A modified Fontan procedure was done when the patient was 6 years old. She improved, but decongestive drugs were still necessary. A new left basilar systolic murmur then became apparent. By 8 years of age, increasing cardiac failure with ascites developed and the murmur was associated with a thrill. Recatheterization showed a gradient of 136 mm Hg across the BVF. Pressure in the ventricle was 212/9 to 14 mm Hg and the pulmonary artery A wave was 22 mm Hg. At operation, with hypothermia and cardiac arrest, considerable distortion of the pulmonary artery incident to prior banding and Fontan-type procedures was found. A pulmonary artery-ascending aorta bypass procedure seemed technically infeasible. A ventricle-ascending aorta bypass was decided on. The anterior wall of the ventricle was incised at the junction of its middle and distal thirds and a full-thickness elliptical segment of myocardium was Accepted for publication Sep 29, 1988. Address reprint requests to Dr Reynolds, Children's Heart Clinic, 2633 Napoleon Ave, Suite 1000, New Orleans, LA 70115.
0 1989 by The Society of Thoracic Surgeons
excised; the ventriculotomy was enlarged to a diameter of about 25 mm. A Dacron graft 23 mm in diameter with a No. 21 St. Jude mechanical prosthetic valve was sutured into the midportion of the conduit, the proximal end of which was anastomosed, using another running 4-0 Prolene (Ethicon, Inc, Somerville, NJ) suture, to the ascending aorta. Simultaneous aortic and ventricular pressures were equal at the end of the procedure. The patient was weaned from cardiopulmonary bypass without the need for inotropic agents. When last examined 11 months postoperatively, the patient was doing well, attending school, and gaining weight. Her preoperatively gigantic liver was no longer enlarged, and there was no edema, but decongestive drugs were still necessary to control abdominal swelling.
Comment In patients such as ours with the common type of single ventricle, stenosis of the BVF is a progressive, often covert, frequent (84%), and potentially lethal problem [l]. The increasing ventricular hypertrophy and fibrosis that BVF obstruction entails elevate ventricular pressures and decrease compliance. Both pulmonary banding and the modified Fontan procedure can initiate or accelerate foramen stenosis [2, 31. Foramen stenosis has been attacked directly via transoutlet chamber resection, aortotomy, or right atriotomy, but iatrogenic heart block frequently results, coronary artery and ventricular injury is possible, inadequate resection is frequent, restenosis can occur, and the mortality rate with the direct approach is very high [3-51. Bypassing the subaortic obstruction by insertion of a ventricular apex-descending thoracic aorta valved conduit has been uniformly unsuccessful (3, 61. Another approach has been to anastomose the proximal main pulmonary artery, with or without transsection, to the ascending aorta in order to bypass outlet stenosis [24, 6, 71. The distal pulmonary artery is connected either to the right atrium (Fontan) or to the aorta in some fashion (systemic-pulmonary artery shunt). Penkoske and associates [2] reported doing simultaneous arterial switch and modified Fontan procedures to bypass outflow tract obstruction. It i s evident, if only from the variety of operations suggested, that surgical palliation of subaortic outflow tract obstruction in single-ventricle hearts is problematic and difficult. The main pulmonary artery-ascending aorta diversion is apparently the most successful approach to the problem [ 3 ] . However, of 19 patients reviewed-all anatomically similar to ours and reported in the English0003-4975/89/$3.50
766
BETHEA AND REYNOLDS BYPASS O F BULBOVENTRICULAR FORAMEN STENOSlS
language medical literature since 1981-who underwent this procedure, 8 died: an operative mortality of 42% for the liest operation to date. Both Rothman and co-workers 131 and Barber and co-workers [4] relate operative success to the magnitude of the subaortic pressure gradient, and found no surgical survivors with gradients greater than 75 and 66 mm Hg, respectively. Only one patient-a surgical nonsurvivor with a gradient of about 140 mm Hg [4]-of all those reported in surgical series silice 1981 had a transforamen pressure gradient greater than our patient's 136-mm Hg gradient. The ventricleascending aorta valved-conduit bypass procedure used in our patient has several advantages. It is probably applicable to all ages beyond infancy, and subsequent to pulmonary artery banding and Fontan-type procedures. There is little chance of producing heart block. It is technically easier than dividing and anastomosing the posteriorly located pulmonary artery, especially if it was previously banded. The conduit and valve are replaceable should the need arise because of degenerative changes or patient growth. Valve conduits do, of course, entaiI the risks of maintenance, and some myocardium is sacrificed when they are placed. An allograft conduit could be used as an alternative to a synthetic prosthesis. As experience to date with operations for relief of subaortic stenosis in patients with univentricular hearts is
A n n Thor'ic Surg 1989;47:765-6
so dismal, the ventricle-ascending aorta valved-conduit bypass operation should be considered as an alternative.
References 1. Freedom RM, Benson LN, Smallhorn JF, et al. Subaortic stenosis, the univentricular heart, and banding of the pulmonary artery: an analysis of the course of 43 patients with univentricular heart palliated by pulmonary artery banding. Circulation 1986;73:75%64. 2. PenkoskP PA, Freedom RM, Williams WG, et al. Surgical palliation of subaortic stenosis in the univentricular heart. J Thorac Cardiovasc Surg 1984;87:767-81. 3. Rothman A, Lange P, Lock JE, et al. Surgical management of subaortic obstruction in single left ventricle and tricuspid atresia. J Am Coll Cardiol 1987;10:4214. 4. Barber G, Hagler DJ, Edwards WD, et al. Surgical repair of univentricular heart (double inlet left ventricle) with obstructed anterior subaortic outlet chamber. J Am Coll Cardiol 1984;4:771-8. 5. Newfield EA, Nikaidoh H. Surgical management of subaortic stenosis in patients with single ventricle and transposition of the great vessels. Circulation 1987;76(Suppl 3):29-33. 6. Jonas RA, Castaneda AR, Lange P. Single ventricle (single- or double-inlet) complicated by subaortic stenosis: surgical options in infancy. Ann Thorac Surg 1985;39:361-6. 7. Park SC, Siewers RD, Neches WH, et al. Surgical management of univentricular heart with subaortic obstruction. Ann Thorac Surg 1984;37:417-21.
Treatment of Bulboventricular Foramen Stenosis by Ventricle-Ascending Aorta Valved-Conduit Bypass Morrison C . Bethea, MD, and James L. Reynolds, MD Southern Baptist Hospital, New Orleans, Louisiana
An 8-year-old girl with single ventricle and l-transposition developed severe stenosis of the bulboventricular foramen. This became critical subsequent to pulmonary banding and a modified Fontan operation. Successful relief of the obstruction was achieved by placing a valved conduit between the ventricle and ascending aorta, thus bypassing the obstruction. (Ann Tlzorac Surg 1989;47:765-6)
S
urgical relief of bulboventricular foramen (BVF) stenosis is difficult. We report an alternative technique for bypassing such an obstruction. The patient, an 8-year-old girl, had a heart murmur and cardiac failure at 7 weeks of age. Cardiac catheterization at that time showed a double-inlet, single ventricle with 1-transposition. A subaortic rudimentary outflow tract chamber was connected by way of an unrestrictive BVF to the single ventricle, and an unobstructed pulmonary artery arose directly from the ventricle. Because of intractable cardiac failure, the pulmonary artery was surgically banded when the infant was 3 months of age. She improved progressively, but by 4 years of age, cyanosis appeared. One year later, repeat catheterization showed the following pressure measurements (mm Hg): main pulmonary artery, 24/14; left atrium (mean), 8; left ventricular end-diastolic, 6.5 to 10.5; BVF gradient, 10. Pulmonary resistance was 1.6 units. A modified Fontan procedure was done when the patient was 6 years old. She improved, but decongestive drugs were still necessary. A new left basilar systolic murmur then became apparent. By 8 years of age, increasing cardiac failure with ascites developed and the murmur was associated with a thrill. Recatheterization showed a gradient of 136 mm Hg across the BVF. Pressure in the ventricle was 212/9 to 14 mm Hg and the pulmonary artery A wave was 22 mm Hg. At operation, with hypothermia and cardiac arrest, considerable distortion of the pulmonary artery incident to prior banding and Fontan-type procedures was found. A pulmonary artery-ascending aorta bypass procedure seemed technically infeasible. A ventricle-ascending aorta bypass was decided on. The anterior wall of the ventricle was incised at the junction of its middle and distal thirds and a full-thickness elliptical segment of myocardium was Accepted for publication Sep 29, 1988. Address reprint requests to Dr Reynolds, Children's Heart Clinic, 2633 Napoleon Ave, Suite 1000, New Orleans, LA 70115.
0 1989 by The Society of Thoracic Surgeons
excised; the ventriculotomy was enlarged to a diameter of about 25 mm. A Dacron graft 23 mm in diameter with a No. 21 St. Jude mechanical prosthetic valve was sutured into the midportion of the conduit, the proximal end of which was anastomosed, using another running 4-0 Prolene (Ethicon, Inc, Somerville, NJ) suture, to the ascending aorta. Simultaneous aortic and ventricular pressures were equal at the end of the procedure. The patient was weaned from cardiopulmonary bypass without the need for inotropic agents. When last examined 11 months postoperatively, the patient was doing well, attending school, and gaining weight. Her preoperatively gigantic liver was no longer enlarged, and there was no edema, but decongestive drugs were still necessary to control abdominal swelling.
Comment In patients such as ours with the common type of single ventricle, stenosis of the BVF is a progressive, often covert, frequent (84%), and potentially lethal problem [l]. The increasing ventricular hypertrophy and fibrosis that BVF obstruction entails elevate ventricular pressures and decrease compliance. Both pulmonary banding and the modified Fontan procedure can initiate or accelerate foramen stenosis [2, 31. Foramen stenosis has been attacked directly via transoutlet chamber resection, aortotomy, or right atriotomy, but iatrogenic heart block frequently results, coronary artery and ventricular injury is possible, inadequate resection is frequent, restenosis can occur, and the mortality rate with the direct approach is very high [3-51. Bypassing the subaortic obstruction by insertion of a ventricular apex-descending thoracic aorta valved conduit has been uniformly unsuccessful (3, 61. Another approach has been to anastomose the proximal main pulmonary artery, with or without transsection, to the ascending aorta in order to bypass outlet stenosis [24, 6, 71. The distal pulmonary artery is connected either to the right atrium (Fontan) or to the aorta in some fashion (systemic-pulmonary artery shunt). Penkoske and associates [2] reported doing simultaneous arterial switch and modified Fontan procedures to bypass outflow tract obstruction. It i s evident, if only from the variety of operations suggested, that surgical palliation of subaortic outflow tract obstruction in single-ventricle hearts is problematic and difficult. The main pulmonary artery-ascending aorta diversion is apparently the most successful approach to the problem [ 3 ] . However, of 19 patients reviewed-all anatomically similar to ours and reported in the English0003-4975/89/$3.50
766
BETHEA AND REYNOLDS BYPASS O F BULBOVENTRICULAR FORAMEN STENOSlS
language medical literature since 1981-who underwent this procedure, 8 died: an operative mortality of 42% for the liest operation to date. Both Rothman and co-workers 131 and Barber and co-workers [4] relate operative success to the magnitude of the subaortic pressure gradient, and found no surgical survivors with gradients greater than 75 and 66 mm Hg, respectively. Only one patient-a surgical nonsurvivor with a gradient of about 140 mm Hg [4]-of all those reported in surgical series silice 1981 had a transforamen pressure gradient greater than our patient's 136-mm Hg gradient. The ventricleascending aorta valved-conduit bypass procedure used in our patient has several advantages. It is probably applicable to all ages beyond infancy, and subsequent to pulmonary artery banding and Fontan-type procedures. There is little chance of producing heart block. It is technically easier than dividing and anastomosing the posteriorly located pulmonary artery, especially if it was previously banded. The conduit and valve are replaceable should the need arise because of degenerative changes or patient growth. Valve conduits do, of course, entaiI the risks of maintenance, and some myocardium is sacrificed when they are placed. An allograft conduit could be used as an alternative to a synthetic prosthesis. As experience to date with operations for relief of subaortic stenosis in patients with univentricular hearts is
A n n Thor'ic Surg 1989;47:765-6
so dismal, the ventricle-ascending aorta valved-conduit bypass operation should be considered as an alternative.
References 1. Freedom RM, Benson LN, Smallhorn JF, et al. Subaortic stenosis, the univentricular heart, and banding of the pulmonary artery: an analysis of the course of 43 patients with univentricular heart palliated by pulmonary artery banding. Circulation 1986;73:75%64. 2. PenkoskP PA, Freedom RM, Williams WG, et al. Surgical palliation of subaortic stenosis in the univentricular heart. J Thorac Cardiovasc Surg 1984;87:767-81. 3. Rothman A, Lange P, Lock JE, et al. Surgical management of subaortic obstruction in single left ventricle and tricuspid atresia. J Am Coll Cardiol 1987;10:4214. 4. Barber G, Hagler DJ, Edwards WD, et al. Surgical repair of univentricular heart (double inlet left ventricle) with obstructed anterior subaortic outlet chamber. J Am Coll Cardiol 1984;4:771-8. 5. Newfield EA, Nikaidoh H. Surgical management of subaortic stenosis in patients with single ventricle and transposition of the great vessels. Circulation 1987;76(Suppl 3):29-33. 6. Jonas RA, Castaneda AR, Lange P. Single ventricle (single- or double-inlet) complicated by subaortic stenosis: surgical options in infancy. Ann Thorac Surg 1985;39:361-6. 7. Park SC, Siewers RD, Neches WH, et al. Surgical management of univentricular heart with subaortic obstruction. Ann Thorac Surg 1984;37:417-21.