Clinic that treated Joan Rivers denies latest media reports surrounding the comedian's death

New York - The New York clinic where comedian Joan Rivers stopped breathing a week before her death denied on Wednesday ever administering general anaesthesia or conducting a vocal cords biopsy that has been alleged in media reports as contributing to her demise.

It was the first time the Yorkville Endoscopy clinic issued a statement since 28 August, when Rivers was rushed to a nearby hospital from the centre with cardiac arrest. She died at age 81 on 4 September.

New York's Daily News newspaper reported on Wednesday that an unplanned vocal cord biopsy at the clinic had left the Brooklyn-born comedian unable to breathe.

Rivers' doctor, who said he was an ear, nose and throat specialist, asked if he could use the clinic's instruments when another doctor said he had noticed something on Rivers' vocal cords, and Rivers' physician was given the go-ahead, a medical source told the newspaper.

"A biopsy like that should only be done in hospital," the newspaper quoted the unnamed medical source as saying. "If she had been in a hospital when it happened, she might have been OK."

In its statement, the clinic did not mention Rivers by name.

"A biopsy of the vocal cords has never been performed at Yorkville Endoscopy," it said. "General anaesthesia has never been administered."

The cause of Rivers' death is still unknown pending further tests, according to the Office of Chief Medical Examiner.

The clinic did not respond to a telephone request for further information.

The State Health Department is investigating the clinic. It is reviewing documents and medical records and interviewing staff and physicians at the clinic in Manhattan's Yorkville neighbourhood, which opened in February 2013.

The clinic said its board-certified anaesthesiologists use light to moderate sedation and monitor the patient continuously using state-of-the-art equipment.

"Yorkville Endoscopy has strict policies in place for the criteria of who gets treated in this centre versus in a hospital," it said, adding it also has all the airway equipment needed for emergency intubation.

The clinic said it has performed more than 18 000 procedures.