BERLIN, November 23 (RIA Novosti) - Former Soviet President Mikhail Gorbachev is receiving post-surgery treatment at a Munich clinic where an artery operation was performed on him Wednesday to prevent a stroke.

"The 75-year-old patient, admitted to the clinic with pre-stroke symptoms Sunday, had a surgical operation on his right internal carotid artery," said a source from the Ludwig Maximilian University's Grosshadern neurological hospital.

"A detailed X-ray examination, carried out by inserting a contrasting device into the brain vessels, confirmed that the condition was quite serious, with the vital artery narrowed 80% by a cholesterol plaque. Such cases demand immediate surgical intervention," he said.

The carotid arteries are responsible for carrying oxygenated blood to the brain. Cholesterol plaques may narrow or clog the arteries, reducing blood flow, which may lead to a stroke.

Citing an official statement by the Grosshadern clinic's head, Professor Klaus Peter, the source said: "The operation was a success, and the patient is feeling relatively well now."

Gorbachev's daughter, Irina, a doctor by training, is staying at her father's bedside, he said.

The former Soviet leader, world-renowned for his efforts to reshape East-West relations, lost his wife, Raisa, to leukemia in 1999.