Former US Secretary of State Henry Kissinger is recovering from heart surgery at a New York City hospital.

Doctors at New York-Presbyterian Hospital replaced an aortic valve in his heart on Tuesday. Kissinger, 91, is resting comfortably, according to a statement released by the hospital.

The Nobel Peace Prize winner has experienced previous heart trouble, according to CNN, including a triple coronary bypass in 1982 and an angioplasty in 2005.

Kissinger, a Holocaust refugee from his native Germany, served as national security adviser and secretary of state under Presidents Richard Nixon and Gerald Ford. He has remained a prominent voice on US foreign policy, particularly within the Republican Party, since leaving public office.