Summary and recommendations.

It has been estimated that up to 7,000 patients with Björk-Shiley Delrin (BSD) heart valves may be alive as of January 1996, the range of implant durations being from 15 to 27 years. The clinical question was whether these BSD valves could be expected to continue to function satisfactorily or if prophylactic replacement might be warranted. The data presented in this supplement suggest that clinically important regurgitation due to wear of the Delrin disc may occur in some BSD valves years after implantation. Normally functioning valves, however, show more regurgitation than Björk-Shiley Radiopaque Spherical disc valves. Some regurgitation does not therefore necessarily indicate dysfunction of BSD valves. There were only two reported cases of inlet strut fracture. However, there are no reports of catastrophic failure associated with fracture of the Delrin disc. Engineering studies showed no reason to suspect an increased rate of failure of the Delrin disc due to fracture or fatigue. All of the data suggested that the BSD valve will continue to provide years of continuing service. Disc wear, if it occurred, was at a rate which allowed adequate time for diagnosis and non-emergency treatment. The data showed no reason to remove BSD valves prophylactically. Patients should be treated on an individual basis, according to the function of their own valve or valves.