FDA reports malfunction of Calif.-made heart valve Agency encourages review of patient risk

March 13, 1992|By Gina Kolata | Gina Kolata,New York Times News Service

A heart valve that has been implanted through open-heart surgery in more than 20,000 Americans has such a high rate of sudden deadly failure that recipients should talk to their doctors about having them replaced, the Food and Drug Administration said yesterday.

The device, the Bjork Shiley Concavo-Convex heart valve, is made by Shiley Inc. of Irvine, Calif., a subsidiary of Pfize Inc.

Shiley said in a statment that the data cited by the government were from a single study and that it was surprised that the FDA would publicize them before meeting with the company. The company also said it was unclear what the risks of valve replacement were.

The FDA said patients and their doctors should weigh the relative risks of valve failure against those of open heart surgery in deciding whether to replace the valve. But it was not immediately clear how many patients would choose to replace the valves. Overall, the mortality rates for open heart surgery are about 5 percent, but for frail patients the risk can be much higher.

A number of other companies make valves that could replace the Shiley device. The valves cost about $4,000 each, excluding the doctors' fees and hospital costs.

The valves, no longer sold in the United States, were marketed in several sizes worldwide. The FDA said the new data, from a large study in the Netherlands, suggest that the overall failure rate for the size sold in the United States is 0.8 percent a year for patients under the age of 50 with a cumulative failure rate of 6.2 percent over eight years. This size, which operates with a 60-degree opening, had an overall cumulative failure rate of 4.2 percent over eight years.

"Heart surgeons are going to be busy," said Dr. Cecil Vaughn, a Phoenix heart surgeon who has already removed valves from three patients. "It's a very desperate situation."

Dr. Vaughn said the valves fail without warning and seemingly at hTC random, regardless of how long they had functioned successfully.

According to the company, the valve has failed in about 500 patients worldwide, killing at least two-thirds of them.

"Unfortunately, there is no way to test the valve while it is in a patient to find out if there is a potential defect," Dr. Vaughn said. The Dutch researchers studied all 2,303 patients in the Netherlands who had received a Shiley valve. The failure rates they discerned were five times higher than earlier FDA estimates.

The FDA said it had asked Shiley to notify all valve recipients of the risk of fracture and to send letters to doctors enclosing copies of the new study and discussing valve replacement.

In a statement yesterday, Dr. David A. Kessler, commissioner of the drug agency, said it had "an obligation to see that doctors and patients are notified so that they can consider the new information in deciding on a course of action."

Dr. Alan Andersen, director of the Office of Science and Technology at the drug agency, said Shiley valves that operated with smaller openings did not have an excess failure risk.

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