Assuming you mean Nancy Reagan - wife of former usa president Ronald Reagan - her cause of death is listed as congestive heart failure.
Charles Tate Regan died on 1943-01-12.
Donald Regan died on June 10, 2003 at the age of 84.
Jamie Regan died on July 10, 2010, in Portland, Oregon, USA.
Barry Regan died on January 16, 1956, in Hollywood, California, USA.
Regan Callais died on January 22, 1988, in Orange County, California, USA.
Richard R. Nacy died in 1961.
Right Now Nancy Wake is NOT dead
Simon Regan died in 2000.
Pat Regan died in 2008.
Charles Regan died in 1921.
Con Regan died in 2007.
Ted Regan died on 1943-07-09.
Larry Regan died on 2009-03-09.
Joe Regan died on 1948-11-18.
Bill Regan died on 1968-06-11.
Kenneth M. Regan died in 1959.
John Keating Regan died in 1987.