Study design and rationale for ELPIS: A phase I/IIb randomized pilot study of allogeneic human mesenchymal stem cell injection in patients with hypoplastic left heart syndrome.

Despite advances in surgical technique and postoperative care, long-term survival of children born with hypoplastic left heart syndrome (HLHS) remains limited, with cardiac transplantation as the only alternative for patients with failing single ventricle circulations. Maintenance of systemic right ventricular function is crucial for long-term survival, and interventions that improve ventricular function and avoid or defer transplantation in patients with HLHS are urgently needed. We hypothesize that the young myocardium of the HLHS patient is responsive to the biological cues delivered by bone marrow-derived mesenchymal stem cells (MSCs) to improve and preserve right ventricle function.