A pilot study involving seven patients found the treatment can repair heart tissue damaged after the initial attack.
Ten years after their treatment, six out of seven patients had near normal heart function. Before the study, three of them had such severe heart failure they were being considered for transplants.
The one patient who did not respond had suffered his heart attack eight years before receiving therapy. The others were treated within 24 weeks.
Experts from the biotech company CellProthera, which developed the treatment, says the results highlight that timing is key for success.
Professor Philippe Henon, who created the technique, said the graft should be carried out between one and six months after a heart attack.
If it is done too early, the damaged tissue is too soft to accept the cells, and if it is too late, the tissue becomes too hard and calcified.
Professor Philippe Henon, Chairman and Chief Scientific Officer, CellProthera
The pilot study is part of an early phase clinical trial that is being carried out at sites in the UK and France, including the British Heart Foundation Centre for Cardiovascular Science at the University of Edinburgh.
The therapy involves taking a blood sample from patients – around half the amount taken in a usual blood donation - and isolating specific stem cells called CD34+ cells.
These cells are injected directly into the patient’s heart. There they have the potential to repair damaged cardiac muscle and the small blood vessels that supply it.
The procedure is less invasive than other stem cell therapies that have been tested in the past. These have involved harvesting the cells from bone marrow.
This is a potentially life-changing therapy for a significant number of patients with heart failure after a heart attack.
Professor David Newby, BHF Centre for Cardiovascular Science, University of Edinburgh
Around a quarter of people who survive a major heart attack are left with heart failure as a result of damage to cardiac tissue.
The researchers are now recruiting 44 people with with heart failure to take part in the ongoing clinical trial.
Source: University of Edinburgh