Human heart valve transplantation, a 25-year-old technique, is beginning to catch on, spurred by improvements in organ procurement and storage. In recent weeks, cardiac surgeons at Fairfax and Georgetown University hospitals have used frozen human heart valves instead of pig heart valves or mechanical devices in patients whose own valves were failing.

"Human valves are the newest wrinkle on the scene," said Dr. Quentin Macmanus, the Fairfax cardiac surgeon who performed his first human valve transplant last week. Human valves, he said, are less prone to infection than other replacements and, surprisingly, are not rejected by the host's body.

Pig valves, which have been used for years, tend to deteriorate over time, he said, and while the plastic and metal replacements are more durable, they can cause blood clots, requiring patients to take blood-thinning medication.

In a recent operation, Macmanus obtained a frozen aortic valve from the Virginia Tissue Bank in Virginia Beach for use in a 50-year-old man whose valve was damaged by a bacterial infection.

The aortic valve maintains the flow of fresh, oxygenated blood from the left ventricle to the aorta, the body's largest artery.

The three-hour operation went smoothly, hospital officials said.

Richard A. Hopkins, a Norfolk heart surgeon who has used human donor valves in some 70 procedures, said the valves, first used in the early 1960s, have been more widely used in New Zealand, Australia and England. Because immunosuppression is not required, these valves are particularly useful in patients who live in areas where follow-up care and monitoring is difficult.

While the fibrous cadaver valves are "mechanically more difficult to put in," Hopkins still finds them superior to other types. He said the cadaver valves are particularly useful in children who are naturally accident prone and therefore do not do well on blood-thinning medication.

Both doctors credit improvements in organ procurement and the use of liquid nitrogen for long-term storage of donated tissue as a blessing for patients needing valve replacements.

While there are plenty of human valves available now, Macmanus is worried that the supply will be depleted soon unless the public becomes "aware that every tissue in the body can be used for somebody else," Macmanus said.