Patients with ischemic heart disease, a serious condition that occurs when the heart's arteries become clogged with cholesterol plaque, may have new options if they have exhausted traditional cardiovascular therapies. A clinical trial at the Massachusetts General Hospital (MGH) Heart Center is using patients' own stem cells to improve circulation in hearts damaged by inadequate blood flow, by promoting the growth of new, microscopic blood vessels.
The clinical trial, called the Autologous Cellular Therapy CD34-Chronic Myocardial Ischemia (ACT34-CMI) trial, is aimed at patients who continue to experience severe chest pain and have failed conventional therapies with medication, angioplasty and stenting, and bypass surgery.
Douglas Drachman, MD, an interventional cardiologist at the MGH Heart Center and the lead investigator along with Kenneth Rosenfield, MD, describes the stem cell therapy as a very promising technique that may encourage growth of new blood vessels on the heart, thereby improving blood flow to the vital heart muscle. Better circulation allows more blood and oxygen to reach the heart, reducing chest pain, also known as angina.
"Stem cell therapy in the ACT-34 CMI trial could offer an important new opportunity for patients who otherwise might have no options - patients who have lifestyle-altering or disabling angina," says Drachman. "This is a new type of therapy that may offer the possibility of real benefit when all conventional treatments - with medication, angioplasty and stenting, and bypass surgery - have failed or are no longer an option."
During this trial, each patient's natural production of stem cells is enhanced through a series of injections of growth factors. The stem cells are then harvested from the bloodstream through a technique called apheresis. Using "NOGA" mapping - a sophisticated catheter-based imaging system that allows physicians to construct and navigate through a three-dimensional image of the heart - the research team determines the exact location in the heart's muscle where improved blood flow is most needed. The catheter system is then used to inject the cells directly into the heart muscle at these sites, with the hope that the cells will stimulate the growth of new blood vessels.
Massachusetts General Hospital is the only site in New England participating in the multi-center ACT-34 CMI trial. Drachman and his colleagues are actively engaged in bringing several other stem cell trials to Mass General in the following year in an effort to improve treatments not only for patients with ischemic heart disease, but also for patients with a variety of other conditions ranging from advanced congestive heart failure to critically reduced circulation in the legs.
Ischemic heart disease, also called coronary artery disease or coronary heart disease, is a leading health problem in the United States. According to Circulation, the journal of the American Heart Association, coronary heart disease caused one out of every five deaths in the United States in 2004. In 2008, it is estimated that 770,000 Americans will have a new coronary attack and about 430,000 will have a recurrent attack.
When the coronary arteries leading to the heart become blocked due to build-up cholesterol plaque and blood clots, the blood flow and oxygen supply to the heart muscle is impaired. The resulting ischemic heart disease is a major cause of severe chest pain, heart attacks, and sudden death.
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