Joseph,

Once the immediate post-op period has passed, bypass surgery does not cause easy bruising or bleeding.  However, medications used after surgery can sometimes cause these problems.  These medications include aspirin, plavix, and coumadin.  If these symptoms become a problem, and there seems to be excessive bruising or bleeding, your Uncle's physician should be made aware, so that he can check what meds he is taking, their doses, and possibly run some tests to monitor the activity of these medication.  Of these medications, coumadin (warfarin) needs to be monitored on a regular basis, as too much can cause bleeding internally, as well as on the skin.

Hope this has been helpful.

Martin Cane, M.D.