Sestak said in the letter that he put the Philadelphia center's director, Richard Citron, on notice "that failure to identify any other reports reflecting poorly on the VA would represent a breach of faith and trust with our veterans, their families and the American public."
The congressman said he warned Citron and another top VA official last fall, after the Trib disclosed another highly critical report on the nursing home, which is part of the Philadelphia VA complex.
Citron could not be reached for comment.
VA officials say deficiencies cited in the two reports were corrected by hiring staff and installing monitoring equipment.
The report on the thoracic-surgical unit included statements from a surgical resident, who told inspectors the care provided in the unit was so bad that a patient who died on a toilet was not discovered until after his body was cold.
In his letter, Sestak noted the inspection reports came during the time when dozens of veterans diagnosed with prostate cancer were treated with improper radiation doses.
He said the problems indicate the need for "urgent action to change the way the VA handles inspections." He said the VA declined to make key staff available for interviews during a 2007 review.
Sestak's letter urged Shinseki to support a bill the congressman filed that would mandate making inspection reports for VA facilities public.
"This latest report paints a stark picture of problems with thoracic-surgery patients in June 2007," Sestak wrote. He said that "not once in my many visits to the PVAMC was this inspection report mentioned."
Sestak is seeking to unseat U.S. Sen. Arlen Specter, D-Philadelphia, in the May 18 primary.
"The conditions reported at the Philadelphia VA Medical Center in 2007 are extremely troubling," Specter said, but noted that VA officials said they have taken steps to correct deficiencies. He said he met recently with Shinseki "to review the entire VA program."
"I continue to be concerned about veterans' care generally," Specter said.