Garcia Sabrido examined Castro in Havana late last year and is a consultant to the Cuban leader's medical team.
The head of surgery at Madrid's Gregorio Maranon hospital, Sabrido said the outlook for any patient of Castro's age who had undergone complications after surgery, was very serious.
"For a patient of his age, who has had complications after an operation, it's always going to be a general prognosis," Garcia Sabrido said, when asked if Castro was in a "very serious condition", as reported by El Pais.
|"[Castro] is one of those men who will never die. He will always live on." |
Hugo Chavez, president of Venezuela
The newspaper had said that the Cuban president is suffering from diverticulitis, an inflammation of the colon that can lead to serious infection if the contents from the intestine leak into the abdomen.
Citing two unidentified sources at the Madrid hospital, El Pais said Castro had undergone three unsuccessful operations including one in which his entire large intestine removed.
Chavez says Castro will 'never die'
On Wednesday, Hugo Chavez, the Venezuelan president, said that the Spanish newspaper reports were specualtion but admitted that Castro's situation has been "delicate" recently.
Chavez said he spoken with the Cuban leader by telephone earlier this month but had been asked to keep it secret so that others did not become jealous.
"About 10 days ago, he called me and we spoke for about half an hour," Chavez said.
Castro "is one of those men who will never die. He will always live on," he added.
The 80-year-old Castro has not been seen in public since he had intestinal surgery in July.