U.S. Cautious on Heart Valve Implant Tester

A device may be able to identify mechanical heart valves in danger of failing, a study showed Wednesday, but the government wants more tests before it is approved.

In the study published in the American Journal of Cardiology, developers of the Valve-Tracker Two said their computerized device may offer a way to detect recipients of Bjork-Shiley heart valves that are at high risk of failure.

About 86,000 people were implanted with the Bjork-Shiley “convexo-concave” heart valve, which was voluntarily withdrawn from the market in 1986--five years after the first reports of life-threatening valve fractures surfaced.

At least 50,000 people worldwide still have the valves in their chests, including about 20,000 in the United States. At least 250 people have died of fractured valves, although consumer groups estimate the toll may be as high as 750 because not all the deaths have been reported to officials.

The valve was manufactured by Irvine-based Shiley Inc., a subsidiary of Pfizer Inc. of New York.

Currently, no methods are available to doctors to test valve recipients to see if their valves have a closure pattern that Pfizer engineers say causes the devices to fail.

The Food and Drug Administration has refused to approve a request by Gerald Kien, of Barrington, Ill., developer of the Valve-Tracker Two, to market his device for screening patients with potentially defective Bjork-Shiley valves, FDA spokeswoman Susan Cruzan said.

The agency wanted Kien to conduct further tests on patients to prove that the device, which uses a sensitive microphone to record the valve’s sound pattern, is an accurate predictor of valve failure.