Fewer clogged arteries may need stent treatment

A new study gives fresh evidence that many people with clogged heart arteries are being overtreated with stents, and that a simple blood-flow test might help prevent unnecessary care.

Fewer deaths, heart attacks and repeat procedures occurred when doctors implanted fewer of these tiny artery props, using the blood-flow test to decide when they were truly needed, the study found.

Results were published in Thursday's New England Journal of Medicine.

Several reports in recent years have suggested that stents and artery-opening angioplasty procedures were being overused in non-emergency cases, often without giving medicine alone a chance to work.

Concern about stent complications also has made doctors more cautious about elective angioplasty.

"It's really raised a lot of question about when is it appropriate," said Dr. Robert Harrington, director of the Duke Clinical Research Institute, who had no role in the new study.

The finding that blood-flow testing may help guide these decisions "adds another parameter for us to consider," he said.

Non-emergency cases

The test has been around for some years but is used in only about 10 per cent of angioplasties now, several heart specialists said.

More than one million angioplasties are done in the United States each year, and about half are the type in this study — non-emergency cases involving people with narrowings in two or more major heart arteries.

The study was done in the United States and Europe, and involved 1,005 people who were having chest pain because of reduced blood flow to the heart or were recovering from a mild heart attack. All were scheduled to have angioplasty based on the usual test — an X-ray called an angiogram, in which a dye is injected so doctors can see artery narrowings.

Half of the study participants had their narrowed areas treated with angioplasty and stents, as indicated by angiograms alone.

The rest were given a blood-flow test. Doctors place a wire in the artery and measure pressure in front of and beyond the narrowing. This tells whether the narrowing is keeping a big amount of blood from getting through to the heart.

More accurate stent placements

In this group, only narrowings that significantly impeded blood flow were treated with angioplasties and stents.

Results: people given the blood-flow test received, on average, roughly two stents versus roughly three for the others.

A year later, only 13 per cent of them had died, suffered a heart attack or needed further artery treatment, versus 18 per cent of those treated on the basis of angiograms alone. Rates of chest pain at one year were similar.

With the blood-flow test, "we were able to more accurately or more judiciously place stents," and decide which arteries to skip, said Dr. William Fearon, a Stanford University cardiologist who helped lead the study.

Between five and 10 per cent of those given the blood-flow test were able to skip angioplasty and stents altogether, and were prescribed medicines instead, he said.

The study was mostly paid for by Radi Medical Systems Inc., a Swedish company that makes the wire used in the blood-flow test and was recently acquired by St. Jude Medical of St. Paul, Minn.

Several study leaders have consulted or been paid speakers for Radi or various stent makers.

The Radi wire, with a sensor that does the pressure measurement, costs about $750 US versus $100 US for an ordinary angioplasty wire. But it likely saves money by avoiding pricier stents, which cost $2,000 US and up, and possibly some cardiac stress tests, which cost $1,000 US or more, Fearon and other heart specialists said.

A second study should quickly be done to see if the benefit can be confirmed, justifying routine use of the blood-flow test, said Dr. Stephen Ellis, a Cleveland Clinic cardiologist who wrote an editorial accompanying the study.

"If validated, the results really should improve medical care," he said.

A second company — Volcano Corp. in Rancho Cordova, Calif. — also makes a blood-flow testing wire.