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Cardiomyoplasty study ends
Citing too much competition from the successes of other implantable devices and a dwindling patient enrollment, Medtronic ended its cardiomyoplasty study in October.
The Minneapolis-based medical technology firm makes an experimental pacemaker used in the procedure. The technique uses one of the patient’s own latissimus dorsi muscles as a wrap for the heart. There, it is "trained" to respond to electric pacing, beating with the heart in an attempt to improve cardiac performance.
"We’ll continue to make replacement devices available to patients who need them," says Medtronic spokeswoman Jessica Stoltenberg. She says 750 CHF patients have undergone cardiomyoplasty since the procedure began trials in the early 1990s.
Stoltenberg says the program was successful, but with the rise of technologies such as left-ventricular assist devices, patient enrollment in their trials continued to decline. (See related cover story.)
"We’ve pretty much closed it down," says William Anderson, MD, attending and associate professor of cardiothoracic surgery at Deborah Heart and Lung Center in Browns Mills, NJ. "Patients are not being funneled in."
In 1994, Deborah planned to do 20 cardiomyoplasty procedures a year for three years. The clinical trial, which followed a previous one to determine feasibility, called for performing the procedure in 600 patients in 10 centers across the country.
Deborah was able, however, to recruit only two patients. One was randomized to cardiomyoplasty; the other was treated with drug therapy.
Anderson says that beside the success of other techniques, it was difficult to win support from cardiologists. There was a significant amount of morbidity involved, he says, because the patients need a "huge" incision to remove the muscle from the back so it can be wrapped around the heart and sewn in place.
The procedure usually takes six hours to complete. The electronic implant then is used to condition the wrapped muscle so it does not become fatigued and then paces it to beat with the heart.
Anderson says the modest results didn’t help sell the procedure. "Patients do improve, but it’s not a night-and-day change."
Other researchers have reported that their small sample of patients also improved, but the benefits were likely to be due to the way the muscular wrap constricted the heart to prevent some of the typical chamber remodeling and not because the muscle was electrically paced to beat. (See Circulation 1995; 91:2,314-2,318, and 1997; 96:3,665-3,671.)