Heart attack risk with unstable angina

My wife is 46 yrs old and has diabetes and takes insulin.  She had bybass surgery last year and now has a blockage in a branch off an artery that wasn't bypassed.  The decision is being made now as to what should be done because the Dr fears that it is in a bad place and might compromise the main left artery.  If he doesn't stent it, she is at risk for a heart attack because it is causing unstable angina.  She gets pressure for no reason at all now.  He said she is at maximum medicine therapy.  My  questions are why does unstable angina put you at risk for a heart attack?  Is it because of the 50% blockage?  If decision is not to stent it, what happens when that branch becomes 100% occluded by plaque (she plaques up quickly even on heavy statins)?  Should she be doing less strenuous activities?  Thanks for your advice.

[Darcy Green Conaway, MD]

Unstable angina is an "acute coronary syndrome"...this means you have a plaque (atheroclerotic disease) in the artery that is unstable and small pieces are breaking off and causing her chest pain or causing the arteries to spasm (clamp down). Sometimes allowing an artery to completely close off actually improves the symptoms. I think you should have a lengthy conversation with the cardiologist as she is very young and I would be very aggressive, as long as it is anatomically possible.Her activity should be discussed with her physician.