IN January 1983, my wife Jean underwent heart surgery at the Brompton Hospital in London, to replace her failing mitral valve with a mechanical one. So the 25th anniversary

IN January 1983, my wife Jean underwent heart surgery at the Brompton Hospital in London, to replace her failing mitral valve with a mechanical one. So the 25th anniversary of this operation is coming up. This quarter century may be some sort of record, perhaps a 'Google' expert could tell me.I do know it is a tribute to the skill and dedication of the heart team, to the reliability of the American valve manufacturer's product, which has now operated over 900 million times, and to the excellent after-care given by Weston Hospital since we moved to the area in 1984. My family and I thank them all.PETER DALLOSSO - Brent Street, Brent Knoll