Eden Prairie company Acist Medical Systems announced study results Wednesday showing its machines can accurately measure the severity of a blood vessel blockage to determine if a stent is needed.

The company presented the results Wednesday at the EuroPCR interventional cardiology conference in Paris.

Acist sponsored the prospective, observational study of its devices in 169 coronary artery disease patients at 11 hospitals worldwide, including Mercy Hospital in Coon Rapids and the University of Minnesota Medical Center in Minneapolis. All the patients had a diagnostic technique called fractional flow reserve (FFR) performed to see if they had a blocked coronary artery that could trigger problems like a heart attack.

The study found that Acist's thin optical FFR device called the Navvus MicroCatheter, when inserted in the coronary artery, provides nearly the same level of accuracy as other FFR devices that are more complicated for the doctor to use, according to the data presentation.

Acist, which is wholly owned by Italy-based Bracco Group, competes with major medical device companies like Abbott Laboratories and Boston Scientific in an FFR market said to be worth roughly $2 billion a year. Medtronic struck a "co-promotion" agreement with Acist in 2014 to jointly distribute Acist's rapid FFR system, including the Navvus MicroCatheter and the RXi Rapid Exchange console that it plugs into.

The growth of the FFR market is tied to concerns about the wide use of heart stents, which are also sold by Medtronic, Abbott and Boston Scientific.

FFR became popular after studies found doctors were implanting more stents than were needed, often based on X-ray images called angiograms that were less precise than they seemed. FFR measures actual blood flow on both sides of a suspected blockage to see how much blood is making it through.

The device is particularly useful in patients with complex coronary artery disease who have multiple potential blocks in their cardiac anatomy that could be responsible for reduced blood flow. The device can be quickly deployed to directly investigate which blotches on the angiogram are causing reduced flow, and which are not, avoiding unneeded stent procedures in some cases.

Several types of FFR devices are on the market today.

The Acist study compared its microcatheter FFR device with another version known as a "pressure wire" because of a question in the medical community about whether the microcatheter's slightly larger profile in the artery can influence blood flow, and therefore affect the device's readings, according to the presentation Wednesday from study co-investigator and California cardiologist Dr. Matthew Price.

"The FFR data showed that microcatheter technology offered consistent and modestly lower FFR measurements when compared to a pressure wire," said a company statement released Wednesday. "In nearly all of the cases [97 percent], the differences in FFR measurements did not impact clinical decisionmaking."

Joe Carlson • 612-673-4779