I believe it is a setteled issue regarding long term memory loss
due to a by-pass. There has been a study and
over the next four years, there were no significant differences in memory or other mental functions between the heart patients who had bypass, those who took medications, and those who had off-pump surgery.
At four years, however, all three groups of heart patients scored significantly worse on tests of memory, decision-making, and visuospatial relations than the heart-healthy people.