FDA Presses Heart Valve Maker on Breakage : * Medicine: Shiley is asked to inform doctors, patients of a greater risk of failure than previously supposed.
The Food and Drug Administration said Thursday that it has asked Shiley Inc. to inform doctors and patients that some of its heart valves are more likely to break than was previously thought.
The risk may be great enough, the FDA now says, that some patients may want to undergo risky open-heart surgery to replace the artificial valves. A heart valve fracture is often fatal.
The new information on which the FDA is basing its action comes from a Dutch study of 2,303 patients published in February by the respected British medical journal the Lancet. The results have been widely reported by many newspapers, including The Times.
By asking Shiley to tell patients about the study, the FDA in effect has endorsed it, moving faster than it has in the past in the Shiley case.
Shiley has previously quibbled with the Dutch study over minor points but has not disputed its major findings.
Shiley issued a formal response on Thursday criticizing the FDA for choosing “to publicize the matter before a meeting could be held.” The Irvine-based company reiterated its position that the Dutch study is an important single study but should not be singled out as definitive.
Roger Sachs, president of the Shiley Heart Valve Research Center, said in the statement that “most clinical reports” indicate that the risk of death from open-heart surgery to replace a heart valve “is generally higher than the risk of death from valve fracture.”
Advocacy groups have accused the FDA of dragging its feet in getting Shiley to take its heart valves off the market and in persuading the company to tell recipients that their valves might fracture.
It has long been known that some of Shiley’s heart valves break; the FDA has reports of 350 fractures among the 82,000 valves implanted in people worldwide. The valves were taken off the market in 1986, but not before several hundred reported deaths and hundreds of lawsuits against Shiley.
What this new study purports to show is that the risk of fracture for some of the larger sizes of the Bjork-Shiley heart valve is as much as five times greater than had been thought.
According to the study, the risk also depends on the age of the patient--the younger the recipient, the greater the danger of a fracture. Another risk factor is the position of the valve in the heart.
For people under 50 with larger valves, the rate of fracture could be as much as 0.8% a year, the FDA said, using its own estimates based on the Dutch study.
That means, the agency said, that some people may now want to reconsider replacing their heart valves. Those people may have previously ruled out replacement surgery because the danger of open-heart surgery had been thought to be greater than the risk of the valve breaking.
“When a critical device such as a heart valve is found to have a problem that could result in death or serious injury, FDA has 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,” FDA Commissioner David A. Kessler said.
