It’s been over a month since Joan Rivers died. At the time, all we knew was that Rivers was under anesthesia, having what was described as a “routine throat procedure”, later elaborated as examining “voice changes” and stomach reflux that the actress had been experiencing.

We were told that, during the procedure, Rivers went into cardiac arrest, stopped breathing, and was transported from the Yorkville Endoscopy clinic where she was having the procedure to Mount Sinai Hospital.

Reports from there were conflicting. Some said she was recovering. Others said she was “resting peacefully”. We later learned that she was in a medically-induced coma from which she never awoke.

Rivers was 81 years old. The day after she died, a routine examination was begun to determine the exact cause of her death, and to find out if the clinic where she was having the procedure was in any way responsible.

That investigation has now been completed. The medical examiner’s report said that Rivers’ death was due to “therapeutic complications”.

“The classification of a death as a therapeutic complication means that the death resulted from a predictable complication of medical therapy,” the report explained. Rivers complication occurred “during laryngoscopy and upper gastrointestinal endoscopy with propofol sedation for evaluation of voice changes and gastroesophageal reflux disease.”

What happened is described as a “laryngospasm”, a spasm of the vocal cords. She began having difficulty breathing, which limited the supply of oxygen to her heart. That then resulted in an arrhythmia, then eventually cardiac arrest. With no supply of oxygen-rich blood to her brain, Rivers began to die.

The investigation further revealed some other regulatory problems at the practice where Rivers had her procedure. These could result in the business losing its accreditation for Medicare patients, but it has until January, 2015, to correct those. There is no news about whether there is any direct connection between those regulation issues and Rivers’ death.

The center issued a statement about those issues.

“The Center has been working collaboratively with appropriate government regulatory agencies to ensure complete compliance with all regulations. The Center remains open and will continue to collaborate with all accreditation and government regulatory agencies to ensure quality care.”

After the report was released, Melissa Rivers posted this to Twitter:

In response to NYC's Medical examiner's report, we continue to be saddened by our tragic loss. No further comment at this time.

— Melissa Rivers (@MelRivers) October 16, 2014