http://www.nydailynews.com/new-york...tor-id-nyc-physician-report-article-1.1943127 ENID ALVAREZ/NEW YORK DAILY NEWSDr. Gwen Korovin could not be reached for comment Wednesday after a report revealed she was the doctor who performed a biopsy on Joan Rivers' vocal cords. The so-called “patron saint of Broadway singers and actors” was laying low Wednesday after she was unmasked by a web site as the mystery doctor who was working on Joan Rivers when she went into her death spiral. Dr. Gwen Korovin was outed by TMZ.com, which cited “multiple sources” to identify her as the doctor who accompanied the doomed comedienne to an Upper East Side clinic. Korovin, who was canonized by Patti Lupone and is Broadway’s best known ear, nose and throat doctor, was Rivers’ personal doctor and was not authorized to practice medicine at Yorkville Endoscopy. Before the story broke, Korovin fled her E. 77th St. office and could not be reached for comment at her West Village home. A spokewoman for the clinic would not confirm the TMZ.com report. “As per HIPAA laws, we do not identify patients or their physicians,” said Marcia Horowitz. J. COUNTESS/WIREIMAGEJoan Rivers died in early September after she was placed in an induced coma following respiratory and cardiac arrest. Nor was there any comment to the TMZ report from Rivers' daughter, Melissa Rivers, or spokeswoman Judy Katz. Either way, it is a potentially devastating career blow for Korovin, whose celebrity patients have included everyone from Nathan Lane, Hugh Jackman, and Kristin Chenoweth to Julie Andrews, Mick Jagger and the late Luciano Pavarotti. After winning a Grammy in 1999, Celine Dion thanked Korovin for saving her voice. Even before Korovin was named, there were suspicions that she had been with Rivers after CNN reported that an ear, nose and throat doctor has snapped a selfie with Rivers while the “Fashion Police” host was under anesthesia. Rivers, 81, was brought on Aug. 28 to the private clinic on E. 93rd St. for a endoscopy after complaining about being hoarse, sources said. She died eight days later. ANTHONY DELMUNDO/NEW YORK DAILY NEWSYorkville Endoscopy is where Joan Rivers' heart stopped Aug. 28. The Daily News reported a short time later that Rivers had brought along a personal doctor who insisted on performing “a biopsy of the vocal cords” after one of the clinic’s doctors found “something”wrong. That caused Rivers’ larynx to tighten up, cutting off air supply and causing her to go into respiratory and cardiac arrest, sources told The News. The Brooklyn-born Rivers died Sept. 4 after the machines that were keeping her alive were turned off. Her death is now being investigated by the state Health Department and the city medical examiner. Yorkville Endoscopy has not confirmed that Rivers was ever a patient and insists a vocal cord biopsy has never been done at the facility.