Tricuspid atresia with transposition of the great vessels

Single ventricle (single- or double-inlet) complicated by subaortic stenosis: surgical options in infancy

Intracardiac obstruction to the systemic circulation can develop in patients with many forms of congenital heart disease. When transposition of the great arteries accompanies tricuspid atresia, narrowing of the ventricular septal defect (VSD) leads to subaortic stenosis. In a similar fashion, a restrictive bulboventricular foramen compromises systemic arterial outflow in patients who have single left ventricle with subaortic outflow chamber. The same effect can be seen in VSD closure in mitral atresia with normally related great vessels. Although some forms of single ventricle can be treated by ventricular septation, the modified Fontan procedure can be more generally applied to this entity. Pulmonary vascular resistance must be low, however, which excludes the application of the Fontan principle in infants. While pulmonary artery banding may protect the lungs from the development of excessive pulmonary vascular resistance, it may also accelerate the development of subaortic obstruction. We have successfully applied the Norwood operation, as described for hypoplastic left heart syndrome, to palliate subaortic stenosis due to restrictive VSD in 3 infants with single ventricle or atrioventricular valve atresia. Consideration should be given to a primary Norwood procedure in infants with single ventricle in whom subaortic stenosis is likely to develop. Patients who do receive pulmonary artery bands should be followed closely for the development of subaortic stenosis and should undergo an early, physiologically corrective operation if it occurs.

Surgical repair of univentricular heart (double inlet left ventricle) with obstructed anterior subaortic outlet chamber

The results of operation in all patients with univentricular heart and an obstructed anterior subaortic outlet chamber who were operated on utilizing extracorporeal circulation at the Mayo Clinic from 1973 through 1983 were reviewed. Ten of the 18 patients died during the immediate postoperative period and there was one late death. Factors significantly related to operative and immediate postoperative mortality were age at operation, cardiothoracic ratio on X-ray examination, degree of ST depression on electrocardiogram and pressure gradient across the outlet foramen at catheterization. Autopsy in eight cases revealed significant hypertrophy of ventricular myocardium and a small outlet foramen that was considered stenotic relative to either body surface area or aortic root area. The ventricular myocardium showed histologic changes of chronic ischemia that predated the surgical procedure.

Further observations on the spontaneous closure of physiologically advantageous ventricular septal defects in tricuspid atresia: surgical implications

Clinical, angiographic, and pathological findings in 40 consecutive patients with tricuspid atresia were reviewed. In 14 patients, there was evidence of closure of the ventricular septal defect (VSD); it was complete in 8 and partial in the other 6. Eleven of these VSD closures occurred in type I patients (without transposition of the great arteries) and 3 in type II patients (with transposition). Progressive cyanosis, along with increasing polycythemia or the disappearance of a previously heard murmur, or both, was observed in all patients. The incidence of closure of VSD in this lesion was 42%. Progressive muscular "encroachment" of the margins of the VSD with subsequent fibrosis and covering by endocardial proliferation is thought to be the most likely mechanism of closure. For initial palliation of this defect, a Blalock-Taussig shunt--preferably on the left side--is recommended in preference to a Glenn anastomosis, because the latter may leave the left pulmonary circuit without blood supply if the VSD closes. If further palliation is required prior to a Fontan procedure, a Blalock-Taussig shunt on the right side, Glenn anastomosis, or enlargement of the VSD may be performed. In type II patients, a large and nonrestrictive VSD is essential for survival following a Fontan operation. Therefore, the size of the VSD should be evaluated prior to and at the time of surgical correction. If the VSD is small in type II patients, complete bypass of the defect and right ventricle by a pulmonary artery-ascending aorta shunt or by a left ventricle-descending aorta conduit should be performed.

Systemic hypoperfusion in a neonate with tricuspid atresia and transposition of the great arteries. Similarity to the hypoplastic left heart syndrome

Infants with the hypoplastic left heart syndrome present a reproducible appearance that terminates in irreversible shock during the neonatal period. There is disagreement over the exact cause of this appearance. This case involves a newborn infant with tricuspid atresia and transposition of the great arteries, and with the clinical appearance and course usually reserved for neonates with the hypoplastic left heart syndrome. Accurate diagnosis is crucial in all such infants to correctly distinguish those with a hopeless outcome from those amenable to palliative cardiovascular surgery. This case supports the contention that ductal closure alone is not the principal cause of death in infants with hypoplastic left heart syndrome.