NEW YORK (CBSNewYork)Joan Rivers died after suffering a “predictable complication of medical therapy,” the New York City Medical Examiner’s office said Thursday.

The ME said Rivers’ cause of death was “anoxic encephalopathy due to hypoxic arrest during laryngoscopy and upper gastrointestinal endoscopy with propofol sedation for evaluation of voice changes and gastroesophageal reflux disease.”

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That means she suffered brain damage due to a lack of oxygen.

Photos: Joan Rivers Through The Years | Celebrity Deaths

Rivers, 81, went into cardiac arrest at Yorkville Endoscopy this August following a minor, elective vocal cord procedure. Her doctor reportedly performed and unscheduled biopsy during the procedure.

The comedian’s vocal cords seized, a condition called laryngospasm, and cut off her air supply, according to reports.

Rivers died at Mount Sinai Hospital a week later.

The clinic has since been placed under investigation by the New York State health department.

Medical malpractice attorney Steven Harris, who is not involved in the case, says it doesn’t necessarily mean negligence.

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“We know what the cause of death is and we know that happens sometimes when the doctors do everything right. But it doesn’t negate a lawsuit because this is just one doctor’s interpretation of the medical records,” he told WCBS 880’s Jim Smith.

Harris says more information woul dbe needed to know everything going on in the room that day, but that even the most routine procedures have no gaurantees.

“Every time you have surgery, you’re taking another risk,” he said.

Stars, family and friends attended Rivers’ Upper East Side funeral Sept. 7 at Temple Emanu-El.

Howard Stern delivered the eulogy, Broadway singer-actress Audra McDonald sang “Smile” and bagpipers played “New York, New York.”

The lights on the Great White Way were dimmed for Rivers two days later.

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