Cardiac stem cells may one day be an effective treatment for heart failure caused by muscle scarring after a myocardial infarction, according to late-breaking clinical trial results presented at the American Heart Association's Scientific Sessions 2012.

In the Effect of Cardiac Stem Cells In Patients with Ischemic CardiOmyopathy (SCIPIO) trial, heart function and quality of life improved in 20 people treated with their own cardiac stem cells (CSCs).

"This is exciting," said Roberto Bolli, M.D., lead author of the trial, chief of Cardiovascular Medicine and director of the Institute of Molecular Cardiology at the University of Louisville in Kentucky. "The effect of these cells has continued for up to two years, and has gotten stronger. There was also a major reduction in heart scarring."

In 33 patients with heart failure who had undergone coronary artery bypass surgery, researchers removed a tiny piece of heart tissue and isolated heart stem cells called c-kit CSCs. Researchers then grew additional cells to infuse into 20 volunteers assigned to treatment.

Among outcomes found two years after treatment:

• The 13 untreated control patients had no meaningful improvement in their hearts' pumping ability, contraction of the damaged wall of the heart or quality of life at 1 year.
• The LVEF on the 20 treated patients increased from 29.0± 1.7% before CSC infusion to 36.0 ± 2.5% 4 months later (P <0.001) and continued to increase 8.1 percent at one year and, for the eight patients who were followed longer, 12.9 percent at two years.
• Contracting ability of the scarred part of the heart in treated patients improved 7.6 percent at four months, 7 percent at one year and 18.4 percent at two years.
• Heart muscle scarring in nine treated patients who underwent cardiac magnetic resonance reduced significantly, from 34.9 grams before CSCs to 21.6 grams at four months and 18.7 grams at one year. Viable heart muscle increased by 11.6 grams at four months and 31.5 grams at one year.
• Quality of life, measured using an inverse scoring system, improved in the treatment group from 44.1 before CSCs to 25.1 at four months, 19.9 at one year and 22.8 at two years.

"We have not seen any deaths among the patients, or any adverse effects that can be ascribed to the stem cells," Bolli said.

Larger, multi-center studies are needed to confirm the findings, Bolli said.

The Jewish Hospital, University of Louisville, and the National Institutes of Health funded the study. Co-authors' names are on the abstract.