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

Study Overview
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Brief Summary
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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.

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

Conditions
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Hypoplastic Left Heart Syndrome

Participation Criteria
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Eligibility Criteria
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Inclusion Criteria: Individuals with HLHS having undergone Stage I surgical palliation and undergoing planned Stage II palliative Glenn surgery. Individuals up to 18 months of age are eligible if written informed consent can be obtained from both parents and/or legal guardians, unless one parent is not reasonably available. Exclusion Criteria: Severe chronic diseases, extensive extra-cardiac syndromic features, or history of cancer The following complications of congenital heart disease: Any condition requiring urgent, or unplanned procedure within 15 days prior to Stage II surgical repair. Severe pulmonary hypertension (reported in the medical record as >70% systemic pressure). Other clinical concerns as documented by a site investigator that would predict (more likely to happen than not to happen) a risk of severe complications or very poor outcome during or after Stage II surgical repair.

Ages Eligible for Study
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Minimum Age: 0 Months
Maximum Age: 18 Months

Sexes Eligible for Study
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All

Accepts Healthy Volunteers
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No

Study Plan
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How is the study designed?
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Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Children with Hypoplastic Left Heart Syndrome (HLHS)<br>HLHS patients requiring Stage II Glenn surgery | |

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |

 Terms related to the study
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Keywords Provided by Centre Hospitalier Valida
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Hypoplastic Left Heart Syndrome, Stage II palliative surgery, Glenn procedure, Congenital heart defect, Congenital heart disease, Underdeveloped left ventricle