Italian doctors have discovered one of the first heart prostheses, implanted almost 50 years ago by Christiaan Barnard, who performed the world’s first human-to-human heart transplant, during surgery on a 60-year-old woman.

The prosthesis, an artificial mitral valve, is almost 50 years old, according to doctors at San Giovanni di Dio e Ruggi d’Aragona hospital, in Salerno. Upon discovering it, the doctors said there was no record of an older valve having been found.

In 1964, when the woman was five, doctors diagnosed a serious mitral valve anomaly. Five years later, in 1969, family members suggested she travel to South Africa, where at Groote Schuur hospital, in Cape Town, a skilled surgeon could save her life.

The surgeon was Prof Christiaan Barnard, who, two years earlier, had led a surgical team which performed the first human-to-human heart transplant. The operation captured public imagination around the world, and Barnard, an outspoken opponent of South Africa’s apartheid system, became one of the best-known people in the world.

The valve implanted by Barnard in the woman was “still perfectly functional and in excellent condition”, surgeons in Salerno said, who were thrilled with their discovery, which they described as being almost “archaeological” in significance.

“There is no record of any other valve that has lasted fifty years,” the doctors said in a statement published on the hospital’s website.

The woman’s operation was a success and she was discharged from the hospital a few days later.

Although Louis Washkansky, the first heart transplant patient, survived for only 18 days, the second, Philip Blaiberg, lived an active life for 19 months. Four of Barnard’s first 10 patients lived for more than a year, two surviving longer than 10 years, with one surviving into his 24th year.