An extra step before surgery can reduce the number of stents implanted in patients with coronary artery disease, save on associated health-care costs and improve health afterward.

Stents that prop open narrowed arteries and release medicine are widely used, but expensive.

Concerns also are growing about postsurgery complications. Traditionally, doctors rely on X-rays to show them where to position stents. But in people who have abnormalities in multiple arteries it can be hard to decide where and how many stents to put in. And X-rays often lead to under- or overestimation of the problem.

A new study published in The New England Journal of Medicine shows that taking certain blood flow measurements in addition to X-rays while placing stents could lower the rate of events such as heart attack and death, without making surgery longer.

In just over a thousand- patients from twenty medical centers in the United States and Europe, doctors used X-rays to identify artery areas that needed stents. Roughly half of those patients were assigned to get stents based on that assessment. The other half were assigned to get stents only if a certain blood-flow measurement was twenty percent below normal.

Simply put, patients who had the extra step got fewer stents. After a year, eighteen percent of those who had only an X-ray had a heart attack, needed a bypass or repeat stent procedure, or died, compared with thirteen percent who had the additional blood-flow test.

Apparently, sometimes it pays to go with the flow.