Comedian Joan Rivers died of `` therapeutic complications '' during a procedure to evaluate her `` voice changes '' and stomach reflux , the New York medical examiner said Thursday . `` The classification of a death as a therapeutic complication means that the death resulted from a predictable complication of medical therapy , '' the report said . Rivers , 81 , died September 4 , a week after an appointment at Manhattan 's Yorkville Endoscopy clinic . The medical examiner 's investigation ruled that the cause of death was `` anoxic encephalopathy due to hypoxic arrest , '' a medical description of brain damage caused by a lack of oxygen . The arrest happened `` during laryngoscopy and upper gastrointestinal endoscopy with propofol sedation for evaluation of voice changes and gastroesophageal reflux disease , '' the medical examiner 's officer said . The complication in this case was laryngospasm -- a spasm of the vocal cords that makes it difficult to breathe , pathologist and surgeon Bill Lloyd told CNN . The situation was compounded when Rivers went into cardiac arrest . `` She stopped breathing and her heart went into arrhythmia because there was n't sufficient oxygen to maintain the heart muscle , '' said Lloyd , who was not involved in Rivers ' autopsy . `` The pump , the heart itself , was unable to move fresh oxygenated blood upstream to the brain . '' At first , Lloyd said , Rivers was unable to bring oxygen into her body due to the vocal cord spasm . After a couple of minutes , her heart started to beat irregularly or completely stopped . Finally , her heart stopped delivering fresh oxygenated blood to her brain , which shut down , according to Lloyd . `` The unanswered question is why they did not do a combat ( tracheotomy ) ? '' he asked . `` You 've seen in the James Bond movies . You take a ballpoint pen and puncture the thyroid cartilage and create an emergency airway for her . Of course , they would do it with sterile instruments . ... And , after minute two , did anybody say , We need to start doing some CPR for her ? '' The initial report did not name the doctor or doctors who performed the procedures . Melissa Rivers posted this on Twitter on Friday afternoon : `` In response to NYC 's Medical examiner 's report , we continue to be saddened by our tragic loss . No further comment at this time . '' Timeline emerges in Joan Rivers ' death . What happened ? Several clinic workers told investigators that the August 28 appointment began with Rivers ' personal throat doctor , Dr. Gwen Korovin , performing a laryngoscopy , which involves using a device to view a patient 's vocal folds , a source close to the investigation told CNN last month . Gastroenterologist Dr. Lawrence Cohen , who was the medical director of the clinic until resigning after Rivers ' death , then performed an endoscopy intended to diagnose why she was suffering a sore throat and hoarseness , the source said . Cohen detected something of concern , the source said . Korovin then began a second laryngoscopy to again view River 's vocal cords , the source said . It was at that time that her vocal cords began to swell , leading to a cutoff of oxygen to her lungs and ultimately to cardiac arrest , according to the source . Korovin was authorized only to observe Cohen , who performed the procedure , since she was not certified by Yorkville Endoscopy clinic , as required by New York health law , the source said . Investigators have found no prior consent form signed by Rivers authorizing a procedure by Korovin , the source said . It was unclear if Rivers had given verbal consent to the biopsy before being sedated . But Korovin denied `` performing an unauthorized procedure '' before the comedian suffered cardiac arrest , a source close to the doctor told CNN last month . Paramedics rushed Rivers from the clinic to New York 's Mount Sinai Hospital a mile away , where she was kept on life support until she died a week later . E ! 's 'Fashion Police ' to continue without Joan Rivers . Doctor to the stars . Korovin is well known for helping an impressive list of celebrities with voice trouble . The list of famous patients who have sung her praises include actors Hugh Jackman and Nathan Lane and singers Celine Dion , Lady Gaga and Ariana Grande . The walls of Korovin 's Manhattan medical office are covered with autographed photos , including from operatic tenor Luciano Pavarotti , Broadway star Barbara Cook and actress-singer Julie Andrews . `` I 've always been fascinated by the human voice and music , '' Korovin , 55 , is quoted telling the New York Daily News in a profile story last year . Korovin 's lawyer sent a statement to CNN last month in response to reports that questioned whether her actions played any role in Rivers ' death . `` Gwen S. Korovin , M.D . is a highly experienced , board certified otolaryngologist . She maintains privileges at one of the city 's most prestigious hospitals . She is respected and admired by her peers in the medical community and she is revered by her patients . `` As a matter of personal and professional policy , Dr. Korovin does not publicly discuss her patients or their care and treatment . Further , Dr. Korovin is prohibited by state and federal confidentiality laws from discussing her care and treatment of any particular patient . ''
Joan Rivers ' death `` resulted from a predictable complication of medical therapy , '' report says . It was `` during laryngoscopy and ... endoscopy with propofol sedation '' The initial report did not name the doctor or doctors . Rivers , 81 , died a week after an appointment at Yorkville Endoscopy clinic .