One in eight U.S. patients who have non-emergency stenting procedures to clear blocked arteries in the heart are likely to see more harm than good from the procedure, researchers said Tuesday.

The findings stoke concern about overuse of the invasive treatment, which costs the nation some $12 billion a year and offers few benefits over drug therapy unless the patient has suffered a heart attack.

“More than half of the inappropriate cases were in patients who didn’t have any symptoms at all,” said Dr. Paul Chan, whose results appear in the Journal of the American Medical Association.

“If they are not benefiting, that’s a problem,” Chan, a cardiologist at Saint Luke’s Health System in Kansas City, Missouri, told Reuters Health.

Each year in the U.S., about 600,000 stents - small metal mesh tubes - are inserted into ailing hearts to prop open blocked arteries, according to the new report.

While they are live-saving for patients with heart attacks and for some patients with severe chest pain even at rest, stents are no better than drugs at preventing new heart attacks or death in patients with stable heart disease.

Apart from a hefty price tag of about $20,000, the stenting procedure carries risks of complications like major bleeding or tears. And after leaving the hospital, people need to take clot-buster medications, which also increase the chance of bleeding.

Chan and his colleagues used data from more than 1,000 hospitals across the country. They checked that data against guidelines developed by several medical groups in 2009 to judge whether the hospitals’ stent use was appropriate or not - that is, whether the benefits were likely to outweigh the harms.

Of about half a million stenting procedures, about 71 percent were done during emergencies such as heart attacks.

Nearly 99 percent of those were deemed appropriate, although the researchers had to exclude more than 100,000 cases that didn’t include sufficient information.

“In the acute setting, we are doing a very good job,” Chan told Reuters Health.

But when patients had stents inserted for less-pressing reasons, the picture was not as pretty.

Almost 55,000 of those procedures, or 38 percent, were of uncertain benefit and 16,838, or 12 percent, were inappropriate. That’s consistent with earlier research suggesting doctors in the U.S. are quicker than others to use stents in patients with stable heart disease.

In just over half of the inappropriate cases, the patients didn’t have any symptoms of heart disease at all, and Chan speculated that a doctor might have sent them to get a stent based on screening results.

That makes little sense, however, because the only proven benefit of stents over drugs in stable heart disease is pain relief.

The researchers also found a lot of variation between hospitals. In one quarter of them, less than six percent of stenting cases were inappropriate, whereas in another quarter of the hospitals, more than 16 percent of stenting procedures were unwarranted.

“This represents an opportunity for those hospital to look at how they perform” stenting, said Dr. William B. Borden, of the Weill Cornell Medical Center in New York, who was not involved in the new work.

However, he said, not all of the cases deemed inappropriate will necessarily do more harm than good. It’s possible, for instance, that a patient might have had a lot of pain even with all the guideline-recommended drugs - beta-blockers and calcium-channel blockers, among others - and would have been a candidate for stenting.

But another expert, Dr. William Boden of Kaleida Health in Buffalo, New York, said the number of inappropriate cases might actually be an underestimate.

Twelve percent “is a low estimate,” he told Reuters Health by email, “because it uses a liberal (American College of Cardiology) definition of what is ‘appropriate.’”

SOURCE:  Journal of the American Medical Association, July 5, 2011.