New developments in the treatment of hypoplastic left heart syndrome

Hypoplastic left heart syndrome (HLHS) was once a uniformly fatal disease, accounting the majority of neonatal deaths due to congenital heart defects. Twenty-five years of advances in the surgical and medical management of this disease have resulted in dramatic improvements in survival for these children. The goal for patients with HLHS should be survival of near 100% with a good quality of life. The advances described in this manuscript detail some of the new techniques used in the surgical and medical management. For infants undergoing staged reconstruction, the Norwood procedure is performed in the newborn period, followed by a hemi-Fontan operation at 6 months of age, and a modified Fontan operation at 1 to 2 years of age. A significant recent modification of the Norwood procedure is the placement of a right ventricle to pulmonary artery (RV-PA) conduit instead of a systemic artery to pulmonary shunt (modified Blalock-Taussig or BT shunt) as the source of pulmonary blood flow. Our recent experience with this modification demonstrated an incremental increase in survival, improved postoperative stability, and decreased inter-stage mortality. At catheterization, significant differences in hemodynamic parameters were present that were consistent with improved coronary blood flow, decreased volume load to the single right ventricle, and improved pulmonary artery growth in those patients with the RV-PA conduit. The 3rd stage in the surgical treatment of HLHS is the modified Fontan operation or cavo-pulmonary anastamosis. A new approach for Fontan completion is the placement of a stent covered with a thin layer of Goretex from the inferior vena cava to the hemi-Fontan baffle. This can be performed in the catheterization laboratory, with a decrease in post-procedure pleural effusions, lower mortality, and a shorter length of stay. The future of treatment for HLHS may eventually involve a single open-heart procedure with initial and final interventions being performed in the catheterization laboratory. Some cardiac centers perform transplantation for management of HLHS. Survival following transplantation has improved as advances in the pre- and post-operative management continue, along with new options for immunosuppression. Treatment for HLHS continues to evolve, as ongoing work has resulted in improved short and long-term survival. The future for children with this disease is encouraging as evidenced by the remarkable achievements made to date and the current worldwide interest and study of HLHS.