Its removal can help some patients overcome rejection problems.

The operation is well established; there are no rejection problems and only size matters when matching a suitable valve to the patient's heart.

By now, I was told, the fever had abated and rejection problems were all in the past.

At a news conference, the surgeons acknowledged their fears of an insurmountable rejection problem.

There could even be some minor rejection problems.

Today, after the rejection problem was solved, it is a common operation in Brazil, performed on thousands of patients every year.

You're saying the previous host kept the symbiont despite ongoing rejection problems?

Such replacement organs do not present rejection problems for the recipient.

Their first subjects had rejection problems, or the biochips failed to take, et cetera.

Although this simplifies the surgery, it does not overcome the rejection problem.