Shiley Testimony Centers on Statistical Safety : Lawsuit: Professor says the heart valve is 99.9% safe. But he concedes that data from only 45% of recipients was available.

A medical statistician testified Thursday that the controversial Shiley heart valve is 99.9% safe, but under cross-examination he conceded that his findings were based on limited data.

Johns Hopkins University professor Ronald Brookmeyer told jurors that recipients of the Bjork-Shiley Convexo-Concave Heart Valve face only a narrow chance of malfunction. His numbers were calculated, however, using information from only 45% of the valve’s recipients.

“What I did was analyze the data I was sent” by the valve’s manufacturer, Shiley Inc., Brookmeyer said.

Shiley’s quest to document statistically the device’s safety is a key element in the case. San Diego County resident Ruth Barillas, 54, a valve recipient, is suing the Irvine-based company in Orange County Superior Court for the anguish she says she has suffered since learning that some of the quarter-sized devices have failed.

Shiley critics say that 900 of the valve’s 86,000 recipients have died because of a structural weakness that sometimes causes one of the device’s minute supporting struts to snap.

Barillas’ attorneys hope to convince jurors that the company misled federal officials and the medical community by downplaying hazards of the valve, which was discontinued in 1986.

Brookmeyer said the primary information source for his one-year study of the valve’s performance came from “implant cards” filled out by doctors and mailed to Shiley. When those cards were not returned, which happened more often than not, information such as patient age, gender and implant date was unavailable.

Though Barillas’ attorney, Kenneth S. Kasdan, referred to Brookmeyer’s technique as “guesstimating,” the statistician testified that the underreporting was balanced by carefully inflating certain numbers to compensate for blanks.

Also testifying Thursday was David Link, an official of the U.S. Food and Drug Administration. He told jurors that his agency and a panel of independent doctors and researchers carefully reviewed the device before it was marketed in 1979.

Link, director of the FDA’s Bureau of Medical Devices, said Shiley provided all requested information during the government’s review of the heart valve, including study of the strut failure already noted in experimental implants. He testified that the device was deemed “reasonably safe and effective.”