'Unbelievable': Heart stents fail to ease chest pain

A procedure used to relieve chest pain in hundreds of thousands of heart patients each year is useless for many of them, researchers reported on Wednesday.

Their study focused on the insertion of stents, tiny wire cages, to open blocked arteries. The devices are lifesaving when used to open arteries in patients in the throes of a heart attack.

But they are most often used in patients who have a blocked artery and chest pain that occurs, for example, walking up a hill or going up stairs. Sometimes patients get stents when they have no pain at all, just blockages.

Heart disease is still the leading killer of Americans — 790,000 people have heart attacks each year — and stenting is a mainstay treatment in virtually every hospital. More than 500,000 heart patients worldwide have stents inserted each year to relieve chest pain, according to the researchers. Other estimates are far higher.

Several companies — including Boston Scientific, Medtronic and Abbott Laboratories — sell the devices, and inserting them costs from $11,000 to $41,000 at hospitals in the United States.

The new study, published in the Lancet, stunned leading cardiologists by countering decades of clinical experience. The findings raise questions about whether stents should be used so often — or at all — to treat chest pain.

“It’s a very humbling study for someone who puts in stents,” said Dr. Brahmajee K. Nallamothu, IHPI member and interventional cardiologist at U-M.

Dr. William E. Boden, a cardiologist and professor of medicine at Boston University School of Medicine, called the results “unbelievable.”

Dr. David Maron, a cardiologist at Stanford University, praised the new study as “very well conducted” but said that it left some questions unanswered. The participants had a profound blockage but only in one artery, he noted, and they were assessed after just six weeks.

“All cardiology guidelines should be revised,” Dr. David L. Brown of Washington University School of Medicine and Dr. Rita F. Redberg of the University of California, San Francisco, wrote in an editorial published with the new study.

Clinical guidelines in the United States say stenting is appropriate for patients with a blocked artery and chest pain who have tried optimal medical therapy, meaning medications like those given to the study patients.

But those guidelines were based on studies in which patients simply said they felt better after having stents inserted.

Stents came into wide use in the 1990s and became the treatment of choice because they were less invasive than bypass surgery. But there have long been questions about their effectiveness.

A large, federally funded study with Dr. Maron as a co-principal investigator, which does not have an untreated control group, is now underway to determine whether medications can be just as effective as stenting or coronary bypass in preventing heart attacks.

In 2007, another large study led by Dr. Boden — also without an untreated control group — found stents did not prevent heart attacks or deaths from heart disease.

The explanation, researchers said, was that atherosclerosis is a diffuse disease. A few arteries might be blocked today, and then reopened with stents. But tomorrow a blockage might arise in another artery and cause a heart attack.

The idea that stenting relieves chest pain is so ingrained that some experts said they expect most doctors will continue with stenting, reasoning that the new research is just one study.