Advances In Science

artificial heart recipient Robert Tools. AP

Measured by headline size, the top medical stories of the year were the anthrax scare, the stem cell controversy and the artificial heart. But some doctors say a less heralded breakthrough may be the biggest news of all, for it will soon improve treatment for hundreds of thousands of Americans with heart disease.

The development is a surprising improvement in the way doctors do angioplasties, one that promises to keep these routine procedures from going bad so they can be done in more people who need them.

In almost every area of medicine -- cancer, diabetes, infectious diseases and more --scientists are making impressive strides, using a molecule-by-molecule understanding of disease to design drugs and devices that tackle the illnesses at their roots.

The latest innovation in treating heart disease shows how this basic understanding pays off. It grows from an intimate knowledge of how smooth muscle cells pile up inside blood vessels in the response to the well-intentioned injury of an angioplasty. Every year, cardiologists perform about half a million of these in the United States and double that worldwide, threading balloons into clogged heart arteries to restore blood flow.

Often, though, the freshly opened arteries fill in again with scar-like growth, a complication that has bedeviled angioplasty since its invention in 1977. Doctors have tried lasers, cutting tools, radiation, even gene therapy, to improve results. In the mid-1990s, they began leaving behind tiny mesh tubes called stents to prop open the arteries.

Some of these help, but nothing solved the problem completely. The arteries still narrow up again about 20 percent of the time.

This history of failure helps explain why doctors are so astonished by what they heard in September at a European cardiology meeting: Testing showed a new kind of stent, coated with growth-stopping medicine, is totally effective. Not a single artery closed up after angioplasty.

"It was too good to believe," says Dr. John LaSala of Barnes-Jewish Hospital in St. Louis. "Nothing in medicine works 100 percent of the time."

And yet, as far as doctors can tell, this one nearly does. Reports on three other companies' stents, similar but coated with different drugs, soon followed. In all, about 700 patients have been studied. The results are remarkably consistent with almost no failures.

"It's an enormous breakthrough," says Dr. David Faxon of the University of Chicago, president of the American Heart Association. "This is the Holy Grail for interventional cardiology."

If no complications emerge, the stents could be on the market next year. Faxon says they could increase angioplasties by 20 percent to 30 percent, because doctors will use them in arteries considered too risky before. These include buildups in especially tiny vessels, ones that are long or diffusely clogged and bad arteries in diabetics.

The new stents were overshadowed by a more dramatic development in cardiology he first artificial heart since the Jarvik-7 in the 1980s. By the end of November, doctors at four hospitals had installed Abiomed's self-contained, fully implanted heart in six men. One did not survive the operation. But the other five came through, although one later suffered a serious stroke.

Nevertheless, the heart itself appeared to work flawlessly, and doctors said it offers a chance of survival for terminally ill people with congestive heart failure who do not qualify for transplanted hearts, which are in short supply.

In cancer research, the biggest news of the year was Gleevec, a new drug effective against an unusual digestive cancer called gastrointestinal stromal tumors. It is also being tested in lung, prostate and brain cancer.

Standard chemotherapy goes after all fast-dividing cells and kills them indiscriminately. But Gleevec follows the new approach to drug design. It is aimed specifically at a protein unique to cancer, blocking it without harming other parts of the body.

"The importance of it is far more than the drug itself," says Dr. Harmon Eyre, research director of the American Cancer Society. "It really is a proof of principle."

Some of the biggest news of the year involved developments that may be years away from practical use but lay the groundwork for future breakthroughs. In February, scientists published their first examination of nearly all the human genetic code. The next task will be learning what all these genes do. The answers will likely hold clues for treating many diseases.

Another field in its infancy is the study of stem cells, the primordial mother cells that give rise to all the body parts. Scientists believe these cells could be used to replace or fix failing organs.

Growing these cells, however, requires the death of a human embryo. In August, President Bush said his administration will pay for this research but limit funding to work on self-perpetuating colonies of stem cells that already existed, not new ones.

For the first time in decades, doctors had to deal with anthrax, spread now through the mail by terrorists. Although five died, modern antibiotics and hospital care often proved effective against the dangerous inhaled form of the disease. The affair also left a mystery: How did two older women in Manhattan and rural Connecticut catch the bacteria?

Another development in infectious disease, however, is likely to affect far more people. In November, the Food and Drug Administration approved the sale of Xigris, the first drug ever for bloodstream bacterial infections, which kill 225,000 people in the United States annually. The drug works by curbing inflammation and clotting, the out-of-control processes that make these infections so dangerous.

For doctors treating diabetes, a major development was proof at last of what many have long suspected: Exercise and weight loss can lower the risk. A study found that walking and losing 15 pounds helped people at high risk to cut heir chance of getting the disease in half.

"This is a major advance," says Dr. Christopher Saudek of Johns Hopkins University, president of the American Diabetes Association. "It had never been proven that a diet and exercise program can have enough effect over a four-year period to actually reduce the risk of new diabetes."

For those who already have the disease, researchers made progress toward developing sensors that continuously measure glucose levels in the bloodstream. Researchers hope eventually to tie this to an implanted insulin pump that will release the hormone in precise response to the body's needs, just as the pancreas does.



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  • CBSNews.com staff CBSNews.com staff

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