CBS New York reported that the New York State health department were investigating her cardiac arrest a week ago, which happened after Rivers went in for an outpatient procedure. From there she was put into a medically induced coma and did not awake.

"My son and I would like to thank the doctors, nurses, and staff of Mount Sinai Hospital for the amazing care they provided for my mother," Melissa Rivers said in a statement. "Cooper and I have found ourselves humbled by the outpouring of love, support, and prayers we have received from around the world. They have been heard and appreciated."

Rivers was known for her confrontational and sometimes raunchy comedy. She was the host of Fashion Police on E! Rivers started her career as a writer and was named the first permanent guest host of the Tonight Show by Johnny Carson, when she took over his show from 1983-86. The two had a falling out when after that she signed on to host her own talk show opposite him on Fox. She made her first return to the show this March, after Jimmy Fallon became the host.