In this study, patients with chronic ischemic cardiomyopathy and EF <50% on optimal medical therapy were randomized to autologous culture expanded mesenchymal cells (=22), autologous bone marrow mononuclear cells (n=22) or placebo vehicle (n=21) delivered by transendocardial stem cell injection (TESI). There were no serious adverse events among any patients undergoing a TESI procedure. Rates of major adverse cardiovascular events did not vary between groups. A possible signal of improved quality of life was observed following treatment with either of the cell types.  At one year, a repeated measures model demonstrated the Minnesota Living with Heart Failure score had improved following treatment with mesenchymal (-6.3; 95% CI -15.0 to 2.4, P=.02) or bone marrow cells (-8.2; 95% CI -17.4 to 0.97, P=.005) but not in the placebo group (0.4; 95% CI -9.45 to 10.25, P=.38). Only mesenchymal cells decreased scar size as a percentage of the LV mass (-18.9%; 95% CI  -30.4 to -7.4, P=.004).

Conclusion

Transendocardial injection of both mesenchymal and bone marrow cells for ischemic cardiomyopathy was safe in this small initial trial.  Signals of quality of life improvement with these therapies are encouraging.  However, this enthusiasm must be tempered against a change in quality of life scores that is at the low end of clinical significance and the performance of multiple comparisons in the study analysis.

Summarized by Steven M. Bradley and Supriya Shore

• Heldman AW, DiFede DL, Fishman JE, et al. Transendocardial mesenchymal stem cells and mononuclear bone marrow cells for ischemic cardiomyopathy: the TAC-HFT randomized trial. JAMA. 2014;311(1):62-73.