Former US vice president Dick Cheney was in hospital Sunday, recovering after a long-awaited and "lifesaving" heart transplant from an unknown donor to whom he will "be forever grateful."
Cheney, 71, a central figure in the "war on terror" launched by the United States in the wake of the September 11 terror attacks and who remains a prominent figure in the Republican Party, has a long history of heart trouble.
He had been on a list for the transplant for more than 20 months, said a statement from his spokeswoman Kara Ahern.
Cheney, who served under president George W. Bush, "is recovering in the intensive care unit of Inova Fairfax Hospital in Falls Church, Virginia, after undergoing heart transplant surgery on Saturday," the statement said.
"Although the former vice president and his family do not know the identity of the donor, they will be forever grateful for this lifesaving gift," it added, without giving further details on his condition.
Cheney has suffered several major health scares.
He suffered his first heart attack in 1978 at the age of 37 and underwent quadruple bypass surgery in 1988. He has since had two artery-clearing angioplasties and in 2001 was fitted with a pacemaker.
In a 2011 interview with NBC News, he said a special pump implanted in his heart the previous year was "a miracle of modern technology" that had kept him alive but was a "temporary measure."
In a statement, Republican presidential candidate Newt Gingrich wished Cheney and his family all the best.
"He has been a colleague and friend for many years, and we are glad that the surgery went well," Gingrich said. In a long political career Cheney served in Congress, the White House and as defense secretary, but gained real prominence while vice president.
He was a driving force behind Bush's foreign policy after September 11 when three civilian jetliners were hijacked and flown into the World Trade Center, the Pentagon, and of a fourth that plummeted into a field in Pennsylvania.