A simple fabric device that looks like fishnet hose but acts like support stockings helped weak hearts pump more efficiently and even shrink back to a more normal size, researchers reported at an American Heart Association (search) conference.

The device is targeted at people with heart failure, which happens when a weak or damaged heart can't pump as forcefully as it should.

The heart enlarges, fluid backs up into the lungs, and people get more and more short of breath and tired, often making many trips to the hospital until their hearts eventually give out.

About 5 million Americans have this condition and more than a million have the type that might be helped by the new stocking-like device.

The mesh stocking is still experimental but its maker, Acorn Cardiovascular Inc. (search) of St. Paul, Minn., already has approval to sell it in Europe and will seek the same from the federal Food and Drug Administration early next year.

The company-sponsored study included 300 patients at 28 hospitals in the United States and one in Canada.

One part involved 193 people having surgery to fix a leaky heart valve, a common problem in heart failure patients. Doctors gave 102 standard surgery and the other 91, surgery plus the heart stocking.

The second part of the study involved 107 people who did not need valve surgery. Fifty were given standard treatment drugs — ACE inhibitors, beta blockers (search) and water pills — and the other 57 got drugs plus surgery to install the stocking.

After an average of two years, 38 percent of the stocking group had improved compared with 27 percent of the others, according to a rating system including survival and other factors. About 37 percent with the stocking got worse compared to 45 percent of the others.

Only 19 stocking recipients needed a transplant, a mechanical heart pump or other major heart operation, but 33 in the other group did.

"We think this stabilizes the disease process" by relieving the pressure on the heart and giving it support so it can rest between beats, Mann said.

Researchers also measured changes in the heart's shape and size and found dramatic differences with the stocking around the organ.

"These big hearts, with this device, became small hearts," and went from a basketball shape to the more natural football shape that lets them beat as they should, Mann said.

The stocking actually changes the size of the cells making up the heart, said Dr. Spencer Kubo, Acorn's medical director.

"If this was just taking a size 8 person and putting them in a size 4 dress, you'd say 'Of course you've made the heart smaller,'" said Kubo. "The mass of the heart is reduced. This is not just a scrunching effect, a corset effect."

The device did not help people avoid hospital stays, but doctors hope it will with longer use. They also hope to develop a way to install it through "keyhole" surgery rather than a big cut in the chest. Company officials would not say what the device is expected to cost.

In other news at the conference:

— A landmark, federally funded study found that ACE inhibitors did no good for people with clogged arteries who already were receiving state-of-the-art care. Such drugs are the gold standard for people with heart failure and artery deposits, and millions more people have been prescribed them in the belief of wider benefits.

But a study of more than 8,000 patients led by Dr. Marc Pfeffer of Brigham and Women's Hospital (search) in Boston found no difference in heart attacks or other measures for those given the drugs versus dummy pills.

"We're already at a floor, we believe. It's hard to show further improvements," he said.

— A pilot project to aggressively manage heart failure by having a nurse individually oversee patients' medications, diets, exercise and other habits failed to save money by reducing hospitalizations and other health care expenses — the key thing it was intended to do.

The study of more than 1,000 people led by the University of Texas Health Sciences Center is expected to shape federal policy on paying for so-called disease management programs for Medicare and Medicaid recipients.