The press here reports on the positive results of a recent small trial of the introduction of stem cells during bypass surgery for heart attack survivors. Stem cell therapies have over the past decade demonstrated highly variable outcomes in patients, and the methodology of delivery has been shown to be very important. A fair amount of the work accomplished in this field over the past fifteen years has involved trying to determine why seemingly similar approaches to the use of stem cells in regenerative medicine can produce both very successful and marginal outcomes. This therapy, for example, isn't all that different from others that have failed to move the needle in heart regeneration.
People suffering from heart disease have been offered hope by a new study that suggests damaged tissue could be regenerated through a stem cell treatment injected into the heart during surgery. The small-scale study followed 11 patients who during bypass surgery had stem cells injected into their hearts near the site of tissue scars caused by heart attacks. One of the trial's most dramatic results was a 40% reduction in the size of scarred tissue. Such scarring occurs during a cardiac event such as a heart attack, and can increase the chances of further heart failure. The scarring was previously thought to be permanent and irreversible.
At the time of treatment, the patients were suffering heart failure and had a very high (70%) annual mortality rate. But 36 months after receiving the stem cell treatment all are still alive, and none have suffered a further cardiac event such as a heart attack or stroke, or had any readmissions for cardiac-related reasons. Twenty-four months after participants were injected with the stem cell treatment there was a 30% improvement in heart function, 40% reduction in scar size, and 70% improvement in quality of life, as judged by the Minnesota living with heart failure (MLHF) score. "It's an early study and it's difficult to make large-scale predictions based on small studies. But even in a small study you don't expect to see results this dramatic. These are 11 patients who were in advanced heart failure, they had had a heart attack in the past, multiple heart attacks in many cases. The life expectancy for these patients is less than two years, we're excited and honoured that these patients are still alive." The next study will include a control group who undergo bypass but do not receive stem cell treatment, to measure exactly what impact the treatment has.