More than 300 patients in Baltimore-area hospitals received a model of an artificial heart valve that the federal Food and Drug Administration says may have a five times higher risk of failure than previously thought.
At least 16 people with the device had contacted area hospitals yesterday, one day after the FDA recommended that they talk to their surgeons about having the valves replaced.
Dr. Joseph McLaughlin, chief of thoracic and cardiovascular surgery at the University of Maryland Medical Center, said his institution implanted about 300 of the large Bjork-Shiley Concavo-Convex heart valves, manufactured by Pfizer Inc., in the 1970s and early 1980s.
A surgeon at St. Joseph Hospital in Towson reported that "a handful" of the devices were implanted there. A spokesman for Johns Hopkins Hospital, the only other hospital to perform heart surgery in this area in the early 1980s, said the devices were never used there.
Pfizer Inc. sold 82,000 of the valves worldwide between 1978 and 1986, when it took them off the market in response to safety concerns. Some physicians found that two tiny metal struts that serve as a hinge on the device sometimes fractured and disabled the valve.
Only the durability of Pfizer's large Bjork-Shiley Concavo-Convex
heart valve is in question. Other Pfizer valves and those manufactured by others are not affected.
So far, the FDA has received 350 reports of valve failure worldwide, resulting in 222 deaths. A consumer group reports that there have been at least 1,000 valve failures resulting in 667 deaths.
Until its action Thursday, the FDA had taken the position that patients who already had the valves should leave them in place. The risk of open heart surgery to replace them, FDA officials had said, was greater than the risk of the valve's fracture.
But at the urging of the Public Citizen Health Research Group in Washington, an arm of Ralph Nader's consumer organization, the FDA reviewed a study conducted in the Netherlands of 2,303 patients with the heart valve.
The study found that the cumulative fracture rate over eight years was 4.2 percent for all patients -- and 6.3 percent among patients un
der age 50.
Dr. McLaughlin said yesterday that he was not yet convinced that the device was unsafe based on "one paper out of Holland, which we don't know all the details of yet." He noted that previous studies in this country showed a much lower fracture rate.
"I don't think people should panic at this point in time," he said. "Most of these valves have done very, very well."
Dr. Garth R. McDonald, a surgeon at St. Joseph Hospital, said people with the affected heart valves should give the question of whether to have them replaced "some very deliberate thought."
"That would be a very intelligent thing to do, rather than take the ap
proach that 'I've got to get my valves replaced tomorrow,' " he said.
Dr. McLaughlin said only one large Bjork Shiley Concavo-Convex valve implanted in a University of Maryland patient has fractured so far.
That device failed soon after it was implanted in 1981 or 1982. But the patient survived and later had
successful open heart surgery to implant a new valve. He has since died of unrelated causes.
But Dr. McLaughlin noted that no one has found a way to build a heart valve that lasts forever. "These are mechanical things," he said. "Every mechanical thing has a certain tendency to break down. . . . None of the valves so far is perfect."