Tenet Tangles With California Blue Cross

Tenet has since downplayed the Blue Cross survey.

"BCC's sample size represents roughly 1.2% of the total [coronary artery bypass graft] patient population during the review period," Stone argued.

More Study

But earlier on Monday, Blue Cross told TheStreet.com that its sample was in fact significant. The company said it reviewed 52 -- or between 17% and 26% -- of the heart bypasses performed on Blue Cross patients at the two Tenet hospitals over the past several years.

Kamil admitted that the sample may not seem particularly large for the two busy cardiac centers overall. But, he added, "it was a huge sample of our patients."

With its reviewers and methodology already in place, Kamil said, Blue Cross is now ready to study other Tenet facilities.

"Any further reviews would he shorter ... hopefully six to eight weeks," he said.