Mesoblast Stem Cell Therapy for Patients With Single Ventricle and Borderline Left Ventricle

This is a prospective, single center, safety and feasibility, blinded, randomized trial to evaluate the use of MPCs in children with complex cardiac anatomy requiring surgical repair. Patients scheduled to undergo bidirectional Glenn (BDG) with future plans for LV recruitment, or patients with a history of BDG who are currently scheduled to undergo LV recruitment will be eligible. Twenty-four subjects will be enrolled, 12 to the MPC treatment arm and 12 to the control arm following a 1:1 randomization schema. Randomization will be stratified according to surgeon to assure random distribution of subjects by surgeon. Families, the biostatistician, all clinical staff outside the operating room, and research staff completing data analysis will be blinded to randomization assignment. The PI, operating room staff, and research staff assisting with delivery will be unblinded to the randomization assignment. Families will be made aware of their randomization assignment once all subjects have completed their study Visit 4. Those randomized to the treatment arm will receive MPCs injected directly into the LV endocardium following clinical surgical maneuvers to recruit the LV (mitral valve repair, aortic valve repair, and/or resection of endocardial fibroelastosis) or BDG. Those subjects randomized to the control arm will receive standard LV recruitment or BDG with no injection. All cardiac tissue acquired as part of a clinically indicated procedure will be collected on enrolled subjects. Most of the tissue sample will be analyzed at the time of collection (histology and H+E stain); the remainder will be banked for potential future testing.