A Prospective Study of Patients With Hypoplastic Left Heart Syndrome (HLHS) Following Stage II Surgical Palliation

Hypoplastic left heart syndrome (HLHS) is a severe form of congenital heart disease that consists of multiple obstructions to flow through the left heart and aorta, as well as hypoplasia of the left ventricle. Most patients require a three-stage surgical protocol starting within days of birth. Stage I of this process is the Norwood reconstruction (within the first few days of life), Stage II (usually required within 3-8 months) involves creation of a direct connection between the patient's superior vena cava and the pulmonary arterial confluence (bidirectional Glenn anastomosis), and the last stage is creation of a Fontan circulation (typically within the first 2-4 years). This "single ventricle" approach requires the right ventricle to perform as the only circulatory pump for the entire body. Our long-term goal is to develop regenerative strategies to strengthen and augment the right ventricular muscle of the single-ventricle heart following surgical palliation in HLHS patients. To determine the safety and feasibility of a cell-based therapeutic intervention at the Stage II surgery, we aim to document the natural history of post-surgical care in HLHS patients having undergone standard of care with protocol specific follow-up over the course of a 6-month period. This prospective study will document the natural history in patients with HLHS after planned Stage II surgical palliation with a focus on cardiovascular parameters within 6 months following surgery in 10 patients.