Comparison of scar size reduction in (A) SCIPIO, (B) CADUCEUS, and (C) POSEIDON trials. A, SCIPIO Trial 1‐year follow‐up shows infarct size reduction at 4 and 12 months after CSC therapy. B, CADUCEUS trial showed decreases in scar mass and increases in viable mass on MRI in patients treated with CDCs but not controls. C, Myocardial infarct (MI) size reduction shown in POSEIDON trial. Panel A reproduced with permission from Chugh et al, Circulation, 20124; panel B from Makkar et al, Lancet, 20125; and panel C from Hare et al, JAMA, 2012.1 CADUCEUS indicates Cardiosphere‐Derived aUtologous stem Cells to reverse ventricUlar dySfunction; CDC, cardiosphere‐derived cell; CSCs, cardiac stem cells; EED, early enhancement defect; MRI, magnetic resonance imaging; MSCs, mesenchymal stem cells; POSEIDON, PercutaneOus StEm Cell Injection Delivery Effects On Neomyogenesis; SCIPIO, Stem Cell Infusion in Patients with Ischemic cardiomyopathy.