The final cause of death for comedian and host Joan Rivers was determined Thursday by the New York City Office of Chief Medical told FOX411 on Thursday. Rivers died on Sept. 4 at the age of 81 after suffering a "predictable complication" during a medical procedure on her throat.

This complication led to a loss of oxygen that caused brain damage, the cause of death statement reported.

"The classification of a death as a therapeutic complication means that the death resulted from a predictable complication of medical therapy," the Office of Chief Medical Examiner's statement said. It continued to say that when Rivers visited Yorkville Endoscopy on Aug. 28 for a laryngoscopy and an upper gastrointestinal endoscopy, she was placed under sedation using propofol to examine changes in her voice.

It was during the New York City clinic's procedure that Rivers went into cardiac arrest and was taken to Mount Sinai Hospital. She was put on life support and died several days later.

The Department of Health in New York launched an investigation into the Yorkville clinic after Rivers' passing. Dr. Lawrence Cohen, Yorkville Endoscopy's medical director, soon left the practice after the star died.

Rivers' only daughter and television partner Melissa Rivers said the family had no comment on the ruling.

"We continue to be saddened by our tragic loss and grateful for the enormous outpouring of love and support from around the world," she said in a recent statement.

Rivers' career was long-lasting and very successful. The comedian worked as a TV talk show host, fashion critic, stage, film and television actress, author and sold a popular line of jewelry. In her book, Rivers even touched on how dying due to natural causes was a boring way to go.

"It's the grand finale, act three the eleven o'clock number -- make it count," she wrote. "If you're going to die, die interesting! Is there anything worse than a boring death? I think not."