LOS ANGELES – Researchers are reporting a key advance in using stem cells to repair hearts damaged by heart attacks. In a study, stem cells donated by strangers proved as safe and effective as patients’ own cells for helping restore heart tissue.

The work involved just 30 patients in Miami and Baltimore, but it proves the concept that anyone’s cells can be used to treat such cases.

Doctors are excited because this suggests that stem cells could be banked for off-the-shelf use after heart attacks, just as blood is kept on hand now.